Methods and compositions for producing ovarian support cell co-culture

Abstract

Featured are methods and compositions for the in vitro maturation of oocytes. In particular, the disclosure features methods and compositions related to engineering a plurality of ovarian support cells (OSCs) for promoting the maturation of an oocyte in a medium. Such methods and compositions are particularly useful for assisted reproduction technology (ART) procedures.

Description

[0001] METHODS AND COMPOSITIONS FOR PRODUCING OVARIAN SUPPORT CELL CO-CULTURE

[0002] TECHNICAL FIELD

[0003] This disclosure relates to the fields of in vitro oocyte maturation and assisted reproductive technology (ART).

[0004] BACKGROUND

[0005] One in ten women struggle with infertility, requiring assisted reproductive technology (ART), such as in vitro fertilization (IVF). Challenges remain with maintaining oocyte health in culture, resulting in low oocyte quality and subsequently poor embryo quality. Furthermore, oocytes that are developmentally immature are traditionally discarded, constricting the available oocyte pool for IVF. In vitro maturation (IVM) holds the promise to mature oocytes in vitro after egg extraction, allowing for utilization of all retrieved eggs. Current methods for IVM are inefficient, using follicle-stimulating hormone (FSH) spike-in to the culture media, showing 5-40% maturation of immature eggs. Even worse, this method results in many unhealthy eggs, with an embryo viability rate under 17%, far lower than for standard IVF. Thus, there remains a need in the field for promoting oocyte maturation for a female subject undergoing an ART procedure.

[0006] SUMMARY OF THE INVENTION

[0007] In one aspect, the disclosure features an ex vivo composition that includes one or more ovarian support cells (OSCs) and one or more diluents or excipients. In some embodiments, the composition promotes the maturation of one or more oocytes.

[0008] In some embodiments, the one or more OSCs include one or more granulosa cells. In some embodiments, the one or more OSCs express FOXL2, AMHR2, CD82, or any combination thereof. In some embodiments, the one or more OSCs express one or more genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB. In some embodiments, the one or more OSCs express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46. In some embodiments the one or more OSCs express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3. In some embodiments, the one or more OSCs express one or more genes selected from FGF2, TGFB1 , and BMP7. In some embodiments, the one or more OSCs express one or more genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4. In some embodiments, the one or more OSCs express one or more genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2. In some embodiments, the one or more OSCs express genes selected from CDH2 and NOTCH2. In some embodiments, the one or more OSCs do not exhibit significant expression of RARRES2. In some embodiments, the one or more OSCs express one or more genes selected from IGF2BP1 , IGF2BP2, and IGF2BP3. In some embodiments, the one or more OSCs further express one or more genes selected from TGFB1 and TGFB2. In some embodiments, the one or more OSCs express one or more genes selected from STRA6, ERBB4, RARRES2, and EGFR. In some embodiments, the one or more OSCs express the gene BMP7. In some embodiments, the one or more OSCs express one or more genes selected from VEGFA and VEGFB. In some embodiments, the one or more OSCs further express the gene PDGFA.

[0009] In some embodiments, the one or more OSCs express NR2F2. In some embodiments, the one or more OSCs include ovarian stroma cells. In some embodiments, the one or more OSCs include granulosa cells and ovarian stroma cells.

[0010] In some embodiments, the one or more OSCs include more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.

[0011] In some embodiments, the one or more OSCs are obtained by differentiation of a population of iPSCs. In some embodiments, the iPSCs are human iPSCs (hiPSCs). In some embodiments, the hiPSCs express or overexpress transcription factor RUNX2. In some embodiments, the hiPSCs express or overexpress transcription factor NR5A1 . In some embodiments, the hiPSCs express or overexpress transcription factor GATA4. In some embodiments, the hiPSCs express or overexpress transcription factor FOXL2.

[0012] In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and NR5A1 . In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors GATA4 and FOXL2.

[0013] In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, GATA4, and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 , GATA4, and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , GATA4, and FOXL2.

[0014] In some embodiments, the transcription factor expression or overexpression is induced by way of a doxycycline-responsive transcription regulatory element, such as a doxycycline-responsive promoter or enhancer.

[0015] In some embodiments, the hiPSCs are contacted with a Wnt / p-catenin pathway activator. In some embodiments, the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof.

[0016] In some embodiments, at least one of the one or more OSCs are encapsulated. In some embodiments, the one or more OSCs are encapsulated in alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly-D-Lactone, or any mixture thereof. In some embodiments, the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof. In some embodiments, the one or more OSCs are encapsulated in laminin, such as laminin-521 . In some embodiments, the one or more OSCs are encapsulated in vitronectin. In some embodiments, the one or more OSCs have reduced expression, or undetectable expression, of one or more genes associated with pluripotency relative to an unmodified iPSC. In some embodiments, the one or more genes associated with pluripotency include NANOG. In some embodiments, the one or more genes associated with pluripotency include POU5F1 .

[0017] In some embodiments, at least one of the one or more OSCs produce one or more growth factors. In some embodiments, the one or more growth factors include insulin-like growth factor (IGF), stem cell factor (SCF), epidermal growth factor (EGF), leukemia inhibitory factor (LIF), vascular endothelial growth factor (VEGF), bone morphogenetic proteins (BMPs), C-type natriuretic peptide (CNP), or any combination thereof. In some embodiments, at least a portion of the one or more growth factors is secreted.

[0018] In some embodiments, the one or more of the OSCs produce one or more steroids. In some embodiments, the one or more steroids include estradiol, progesterone, or a combination thereof. In some embodiments, the one or more steroids are produced in response to hormonal stimulation. In some embodiments, the hormonal stimulation comprises FSH, androstenedione treatment, or a combination thereof. In some embodiments, at least a portion of the one or more steroids is secreted.

[0019] In some embodiments, the one or more OSCs are cryopreserved. In some embodiments, the composition further includes an in vitro maturation (IVM) media. In some embodiments, the IVM media includes a cell culture media. In some embodiments, the IVM media includes Medicult-IVM media. In some embodiments, the IVM media includes one or more supplements. In some embodiments, the one or more supplements include:

[0020] (i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL;

[0021] (ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;

[0022] (iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL;

[0023] (iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;

[0024] (v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

[0025] In some embodiments, the one or more oocytes are retrieved from a donor subject. In some embodiments, the donor subject is from about 19 years old to about 45 years old. In some embodiments, the subject is undergoing ovarian stimulation. In some embodiments, the ovarian stimulation includes treatment with gonadotropin releasing hormone (GnRH). In some embodiments, the ovarian stimulation includes treatment with one or more GnRH analogs. In some embodiments, the one or more GnRH analog is a GnRH agonist or antagonist. In some embodiments, the ovarian stimulation includes one or more ovulatory triggers. In some embodiments, the one or more ovulatory triggers include human chorionic gonadotropin (hCG). In some embodiments, the one or more ovulatory trigger comprises a GnRH agonist, optionally wherein the GnRH agonist is leuprolide. In some embodiments, the ovarian stimulation includes FSH treatment. In some embodiments, the ovarian stimulation does not include FSH treatment. In some embodiments, the FSH treatment includes 300 international units (IU) to 700 IU of FSH. In some embodiments, the FSH treatment includes 400 IU to 600 IU of FSH. In some embodiments, the FSH treatment includes 1 , 2, 3, or more injections of FSH, optionally wherein the FSH treatment includes a plurality of injections, wherein each injection includes a dose of about 100 IU to about 200 IU of the FSH. In some embodiments, the ovarian stimulation further includes clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more doses, optionally wherein each dose is between 50 mg and150 mg (e.g., 50-75 mg, 60-80 mg, 75-100 mg, 90-115 mg, 110-130 mg, 125-150 mg; e.g., 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg). In some embodiments, the ovarian stimulation further includes one or more hCG triggers. In some embodiments, the one or more hCG triggers includes 2,500 IU to 10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose.

[0026] In some embodiments, the one or more oocytes are present in cumulus oocyte complexes (COCs). In some embodiments, the one or more oocytes include one or more denuded immature oocytes. In some embodiments, all of the one or more oocytes are denuded immature oocytes. In some embodiments, the one or more oocytes are not denuded.

[0027] In some embodiments, the one or more oocytes include one or more germinal vesicle (GV)- containing oocytes. In some embodiments, the one or more of the oocytes include one or more oocytes in metaphase I (Ml). In some embodiments, the one or more of the oocytes include one or more oocytes in metaphase II (Mil). In some embodiments, at least a portion of the one or more oocytes include one or more previously vitrified oocytes. In some embodiments, at least a portion of the one or more oocytes include one or more previously cryopreserved oocytes.

[0028] In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs. In some embodiments, prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality. In some embodiments, the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

[0029] In some embodiments, the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs. In some embodiments, the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes. In some embodiments, the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

[0030] In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours. In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs for about 24 hours to about 28 hours. In some embodiments, the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

[0031] In some embodiments, the one or more oocytes are co-cultured in direct contact with the one or more OSCs. In some embodiments, the one or more oocytes do not directly contact the OSCs. In some embodiments, the culture system is a suspension culture. In some embodiments, the culture system is an adherent culture.

[0032] In another aspect, the disclosure features a method of cultivating oocytes, wherein one or more immature oocytes are co-cultured with one or more OSCs.

[0033] In another aspect, the disclosure features a method of preparing one or more oocytes that have previously been retrieved from a human subject for use in an assisted reproduction technology (ART) procedure, the method including co-culturing the one or more oocytes with one or more OSCs.

[0034] In another aspect, the disclosure features a method of producing a mature oocyte for use in an ART procedure, the method including co-culturing one or more oocytes that have previously been retrieved from a human subject with a population of ovarian support cells that have been differentiated from one or more iPSCs.

[0035] In another aspect, the disclosure features a method of inducing oocyte maturation in vitro, the method including co-culturing one or more oocytes with a population of ovarian support cells that have been differentiated from one or more iPSCs, optionally wherein the co-culturing is conducted for a period of from about 6 hours to about 120 hours.

[0036] In another aspect, the disclosure features method of producing a mature oocyte for use in an ART procedure, the method including:

[0037] (a) differentiating one or more iPSCs to produce one or more OSCs;

[0038] (b) retrieving one or more immature oocytes from a subject; and

[0039] (c) co-culturing the one or more oocytes with the one or more OSCs, thereby producing one or more mature oocytes.

[0040] In another aspect, the disclosure features a method of promoting oocyte maturation for a subject undergoing an ART procedure and that has previously been administered one or more follicular triggering agents during a follicular triggering period, the method including:

[0041] (a) retrieving one or more immature oocytes from the subject;

[0042] (b) co-culturing the one or more oocytes with one or more OSCs that have been differentiated from iPSCs, thereby producing one or more mature oocytes; and

[0043] (c) isolating the one or more mature oocytes.

[0044] In some embodiments of any of the preceding aspects, prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml- stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality. In some embodiments, the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

[0045] In some embodiments, the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not include the one or more OSCs. In some embodiments, the one or more co-cultured oocytes have an improved maturation rate compared to oocytes matured in vivo. In some embodiments, the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes. In some embodiments, the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

[0046] In some embodiments, the one or more OSCs include one or more granulosa cells. In some embodiments, the one or more OSCs express FOXL2, AMHR2, CD82, or any combination thereof. In some embodiments, the one or more OSCs express one or more genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB. In some embodiments, the one or more OSCs express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46. In some embodiments the one or more OSCs express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3. In some embodiments, the one or more OSCs express one or more genes selected from FGF2, TGFB1 , and BMP7. In some embodiments, the one or more OSCs express one or more genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4. In some embodiments, the one or more OSCs express one or more genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2. In some embodiments, the one or more OSCs express genes selected from CDH2 and NOTCH2. In some embodiments, the one or more OSCs do not exhibit significant expression of RARRES2. In some embodiments, the one or more OSCs express one or more genes selected from IGF2BP1 , IGF2BP2, and IGF2BP3. In some embodiments, the one or more OSCs express one or more genes selected from TGFB1 and TGFB2. In some embodiments, the one or more OSCs express one or more genes selected from STRA6, ERBB4, RARRES2, and EGFR. In some embodiments, the one or more OSCs express the gene BMP7. In some embodiments, the one or more OSCs express one or more genes selected from VEGFA and VEGFB. In some embodiments, the one or more OSCs express the gene PDGFA.

[0047] In some embodiments, the one or more OSCs include granulosa cells.

[0048] In some embodiments, the one or more OSCs express NR2F2. In some embodiments, the one or more OSCs include ovarian stroma cells.

[0049] In some embodiments, the one or more OSCs include granulosa cells and ovarian stroma cells. In some embodiments, the one or more OSCs include more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.

[0050] In some embodiments, the one or more OSCs are obtained by differentiation of a population of iPSCs. In some embodiments, the iPSCs are hiPSCs. In some embodiments, the hiPSCs express or overexpress transcription factor RUNX2. In some embodiments, the hiPSCs express or overexpress transcription factor NR5A1 . In some embodiments, the hiPSCs express or overexpress transcription factor GATA4. In some embodiments, the hiPSCs express or overexpress transcription factor FOXL2.

[0051] In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and NR5A1 . In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors GATA4 and FOXL2.

[0052] In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, GATA4, and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 , GATA4, and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , GATA4, and FOXL2.

[0053] In some embodiments, the expression or overexpression of any of the foregoing transcription factors is induced by way of a doxycycline-responsive transcription regulatory element, such as a doxycycline-responsive promoter or enhancer.

[0054] In some embodiments, the hiPSCs are contacted with a Wnt / p-catenin pathway activator. In some embodiments, the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof.

[0055] In some embodiments, the one or more OSCs are encapsulated. In some embodiments, the one or more OSCs are encapsulated in alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly- D-Lactone, or a mixture thereof. In some embodiments, the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof. In some embodiments, the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is laminin-521 . In some embodiments, the one or more OSCs are encapsulated in vitronectin.

[0056] In some embodiments, the one or more OSCs have low or undetectable expression of one or more genes associated with pluripotency relative to an iPSC. In some embodiments, the one or more genes associated with pluripotency include NANOG. In some embodiments, the one or more genes associated with pluripotency include POU5F1 .

[0057] In some embodiments, the one or more of the OSCs produce one or more growth factors. In some embodiments, the growth factors include IGF, SCF, EGF, LIF, VEGF, BMPs, CNP, or any combination thereof. In some embodiments, at least a portion of the one or more growth factors is secreted.

[0058] In some embodiments, the one or more OSCs produce one or more steroids. In some embodiments, the one or more steroids include estradiol, progesterone, or a combination thereof. In some embodiments, the one or more steroids are produced in response to hormonal stimulation of the OSCs. In some embodiments, the hormonal stimulation includes exposure to FSH, androstenedione, or a combination thereof. In some embodiments, at least a portion of the one or more steroids is secreted.

[0059] In some embodiments, the one or more OSCs are cryopreserved. In some embodiments, the composition further includes an in vitro maturation (IVM) media. In some embodiments, the IVM media includes a cell culture media. In some embodiments, the IVM media includes Medicult-IVM media. In some embodiments, the IVM media includes one or more supplements. In some embodiments, the one or more supplements includes:

[0060] (i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL; (ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;

[0061] (iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL;

[0062] (iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;

[0063] (v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

[0064] In some embodiments, the one or more oocytes are retrieved from a donor subject. In some embodiments, the donor subject is from about 19 years old to about 45 years old. In some embodiments, the subject is undergoing ovarian stimulation. In some embodiments, the ovarian stimulation includes treatment with gonadotropin releasing hormone (GnRH). In some embodiments, the ovarian stimulation includes treatment with one or more GnRH analogs. In some embodiments, the one or more GnRH analog is a GnRH agonist or antagonist. In some embodiments, the ovarian stimulation includes one or more ovulatory triggers. In some embodiments, the one or more ovulatory triggers include human chorionic gonadotropin (hCG). In some embodiments, the one or more ovulatory trigger comprises a GnRH agonist, optionally wherein the GnRH agonist is leuprolide. In some embodiments, the ovarian stimulation includes FSH treatment. In some embodiments, the ovarian stimulation does not include FSH treatment. In some embodiments, the FSH treatment includes 300 international units (IU) to 700 IU of FSH. In some embodiments, the FSH treatment includes 400 IU to 600 IU of FSH. In some embodiments, the FSH treatment includes 1 , 2, 3, or more injections of FSH, optionally wherein the FSH treatment includes a plurality of injections, wherein each injection includes a dose of about 100 IU to about 200 IU of the FSH. In some embodiments, the ovarian stimulation further includes clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more doses, optionally wherein each dose is between 50 mg and 150 mg (e.g., 50-75 mg, 60-80 mg, 75-100 mg, 90-115 mg, 110-130 mg, 125-150 mg; e.g., 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg). In some embodiments, the ovarian stimulation further includes one or more hCG triggers. In some embodiments, the one or more hCG triggers includes 2,500 IU to 10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose.

[0065] In some embodiments, the one or more oocytes are in cumulus oocyte complexes (COCs). In some embodiments, the one or more oocytes include one or more denuded immature oocytes. In some embodiments, all of the one or more oocytes are denuded immature oocytes. In some embodiments, the one or more oocytes are not denuded.

[0066] In some embodiments, the one or more oocytes include one or more germinal vesicle (GV)- containing oocytes. In some embodiments, the one or more of the oocytes include one or more oocytes in metaphase I (Ml). In some embodiments, the one or more of the oocytes include one or more oocytes in metaphase II (Mil). In some embodiments, at least a portion of the one or more oocytes include one or more previously vitrified oocytes. In some embodiments, at least a portion of the one or more oocytes include one or more previously cryopreserved oocytes. In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs.

[0067] In some embodiments, prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality. In some embodiments, the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

[0068] In some embodiments, the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs. In some embodiments, the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes. In some embodiments, the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

[0069] In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours. In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs for about 24 hours to about 28 hours.

[0070] In some embodiments, the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

[0071] In some embodiments, the one or more oocytes are co-cultured in direct contact with the one or more OSCs. In some embodiments, the one or more oocytes do not directly contact the OSCs. In some embodiments, the culture system is a suspension culture. In some embodiments, the culture system is an adherent culture.

[0072] In another aspect, the disclosure features a method of promoting differentiation of one or more induced pluripotent stem cells (iPSCs) to one or more ovarian support cells (OSCs), the method comprising:

[0073] (a) culturing the one or more iPSCs in vitro;

[0074] (b) inducing, in the one or more iPSCs, expression or overexpression of one or more transcription factors comprising FOXL2, NR5A1 , RUNX2, GATA4, or any combination thereof, thereby producing differentiated cells;

[0075] (c) determining that the differentiated cells resulting from (b) exhibit a gene expression profile that is similar to that of one or more OSCs; and

[0076] (d) co-culturing the one or more OSCs with one or more oocytes previously retrieved from a subject, thereby maturing the one or more oocytes.

[0077] In another aspect, the disclosure features method of producing one or more ovarian support cells (OSCs) from one or more induced pluripotent stem cells (iPSCs), the method comprising:

[0078] (a) culturing the one or more iPSCs in vitro; (b) inducing, in the one or more iPSCs, expression or overexpression of one or more transcription factors comprising FOXL2, NR5A1 , RUNX2, GATA4, or any combination thereof, thereby producing differentiated cells;

[0079] (c) determining that the differentiated cells resulting from (b) exhibit a gene expression profile that is similar to that of one or more OSCs; and

[0080] (d) co-culturing the identified one or more OSCs with one or more oocytes previously retrieved from a subject, thereby maturing the one or more oocytes.

[0081] In another aspect, the disclosure features a method of preparing a composition comprising one or more ovarian support cells (OSCs), the method comprising:

[0082] (a) culturing the one or more iPSCs in vitro;

[0083] (b) inducing, in the one or more iPSCs, expression or overexpression of one or more transcription factors comprising FOXL2, NR5A1 , RUNX2, GATA4, or any combination thereof, thereby producing differentiated cells;

[0084] (c) determining that the differentiated cells resulting from (b) exhibit a gene expression profile that is similar to that of one or more OSCs; and

[0085] (d) co-culturing the identified one or more OSCs with one or more oocytes previously retrieved from a subject, thereby maturing the one or more oocytes.

[0086] In some embodiments of the preceding aspects, the iPSCs are human iPSCs (hiPSCs). In some embodiments, the iPSCs were previously cryopreserved. In some embodiments, the co-culturing is performed in in vitro maturation (IVM) media. In some embodiments, the IVM media includes a cell culture media. In some embodiments, the IVM media includes Medicult-IVM media. In some embodiments, the IVM media includes one or more supplements. In some embodiments, the one or more supplements include:

[0087] (i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL;

[0088] (ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;

[0089] (iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL;

[0090] (iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;

[0091] (v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

[0092] In some embodiments, the induction of iPSCs to OSCs occurs for about 1 day to about 10 days, optionally wherein the induction occurs for about 5 days.

[0093] In some embodiments, the iPSCs are cultured in a media that includes a matrix. In some embodiments, the matrix includes alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly- D-Lactone, or a mixture thereof. In some embodiments, the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof. In some embodiments, matrix includes laminin, optionally wherein the laminin is laminin-521 . In some embodiments, the matrix includes vitronectin.

[0094] In some embodiments, the iPSCs are reprogrammed using a transposase method to carry one or more inducible transcription factors. In some embodiments, the iPSCs are transformed via electroporation, liposome-mediated transformation, or viral-mediated gene transfer. In some embodiments, the expression or overexpression of the one or more transcription factors is induced in the presence of doxycycline. In some embodiments, the iPSCs are contacted with a Wnt / p-catenin pathway activator. In some embodiments, the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof. In some embodiments, the one or more OSCs include one or more granulosa cells.

[0095] In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express FOXL2, AMHR2, CD82, or any combination thereof. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from FGF2, TGFB1 , and BMP7. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2. In some embodiments the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from CDH2 and NOTCH2. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells do not exhibit significant expression of RARRES2. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from IGF2BP1 , IGF2BP2, and IGF2BP3. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from TGFB1 and TGFB2. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from STRA6, ERBB4, RARRES2, and EGFR. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express the gene BMP7. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express one or more genes selected from VEGFA and VEGFB. In some embodiments, the gene expression determination of step (c) includes determining that the one or more differentiated cells express the gene PDGFA.

[0096] In some embodiments, the one or more OSCs include one or more granulosa cells. In some embodiments, one or more OSCs express NR2F2. In some embodiments, the one or more OSCs include one or more ovarian stroma cells.

[0097] In some embodiments, the one or more OSCs include granulosa cells and ovarian stroma cells. In some embodiments, the one or more OSCs include more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.

[0098] In some embodiments, the one or more OSCs have low or undetectable expression of one or more genes associated with pluripotency relative to an iPSC. In some embodiments, the one or more genes associated with pluripotency include NANOG. In some embodiments, the one or more genes associated with pluripotency include POU5F1 .

[0099] In some embodiments, the one or more of the OSCs produce one or more growth factors. In some embodiments, the growth factors include IGF, SCF, EGF, LIF, VEGF, BMPs, CNP, or any combination thereof. In some embodiments, at least a portion of the one or more growth factors is secreted.

[0100] In some embodiments, the one or more OSCs produce one or more steroids. In some embodiments, the one or more steroids include estradiol, progesterone, or a combination thereof. In some embodiments, the one or more steroids are produced in the presence of one or more hormones. In some embodiments, the one or more hormones includes exposure to FSH, androstenedione, or a combination thereof. In some embodiments, at least a portion of the one or more steroids is secreted.

[0101] In some embodiments, the one or more oocytes retrieved from the subject are immature oocytes. In some embodiments, the co-culturing the one or more OSCs with one or more oocytes promotes the maturation of the one or more oocytes. In some embodiments, the method further includes harvesting the one or more oocytes for an assisted reproductive technology procedure.

[0102] In some embodiments, the subject is undergoing ovarian stimulation prior to the retrieval of one or more oocytes. In some embodiments, the ovarian stimulation includes treatment with gonadotropin releasing hormone (GnRH). In some embodiments, the ovarian stimulation includes treatment with one or more GnRH analogs. In some embodiments, the one or more GnRH analog is a GnRH agonist or antagonist. In some embodiments, the ovarian stimulation includes one or more ovulatory triggers. In some embodiments, the one or more ovulatory triggers includes hCG. In some embodiments, the one or more ovulatory trigger includes a GnRH agonist, optionally wherein the GnRH agonist is leuprolide. In some embodiments, the ovarian stimulation includes FSH treatment. In some embodiments, the ovarian stimulation does not include FSH treatment. In some embodiments, the FSH treatment includes 300 IU to 700 IU of FSH. In some embodiments, the FSH treatment includes 400 IU to 600 IU of FSH. In some embodiments, the FSH treatment includes 1 , 2, 3, or more injections of FSH, optionally wherein the FSH treatment comprises a plurality of injections, wherein each injection comprises a dose of about 100 IU to about 200 IU of the FSH. In some embodiments, the ovarian stimulation further includes clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more doses, wherein each dose is between 50 mg and 150 mg (e.g., 50-75 mg, 60-80 mg, 75-100 mg, 90-115 mg, 110-130 mg, 125-150 mg; e.g., 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg). In some embodiments, the ovarian stimulation further includes one or more hCG triggers. In some embodiments, the one or more hCG triggers includes 2,500 IU to 10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose.

[0103] In some embodiments, the one or more oocytes are in cumulus oocyte complexes (COCs). In some embodiments, the one or more oocytes include one or more denuded immature oocytes. In some embodiments, all of the one or more oocytes are denuded immature oocytes. In some embodiments, the one or more oocytes are not denuded prior to or following co-culturing.

[0104] In some embodiments, the one or more oocytes include one or more germinal vesicle (GV)- containing oocytes. In some embodiments, the one or more oocytes include one or more oocytes in metaphase I (Ml). In some embodiments, the one or more oocytes include one or more oocytes in metaphase II (Mil).

[0105] In some embodiments, at least a portion of the one or more oocytes include one or more previously vitrified oocytes. In some embodiments, at least a portion of the one or more oocytes includes one or more previously cryopreserved oocytes.

[0106] In some embodiments, prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality. In some embodiments, the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality. In some embodiments, the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs. In some embodiments, the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes. In some embodiments, the one or more co- cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

[0107] In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours. In some embodiments, the one or more oocytes are cultured with the one or more OSCs for about 24 hours to about 28 hours.

[0108] In some embodiments, method further includes isolating one or more Mil-stage oocytes from the co-culture including the one or more oocytes retrieved from the subject with the one or more OSCs.

[0109] In some embodiments, the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

[0110] In some embodiments, the one or more oocytes are cultured in direct contact with the one or more OSCs. In some embodiments, the one or more oocytes do not directly contact the one or more OSCs. In some embodiments, the co-culture is a suspension co-culture. In some embodiments, the coculture is an adherent co-culture.

[0111] In another aspect, the disclosure features a cell culture system including one or more ovarian support cells (OSCs), wherein the system promotes maturation of one or more oocytes. In some embodiments, the one or more OSCs include one or more granulosa cells. In some embodiments, the one or more OSCs express FOXL2, AMHR2, CD82, or any combination thereof. In some embodiments, the one or more OSCs express one or more genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB. In some embodiments, the one or more OSCs express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46. In some embodiments the one or more OSCs express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3. In some embodiments, the one or more OSCs express one or more genes selected from FGF2, TGFB1 , and BMP7. In some embodiments, the one or more OSCs express one or more genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4. In some embodiments, the one or more OSCs express one or more genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2. In some embodiments, the one or more OSCs express genes selected from CDH2 and NOTCH2. In some embodiments, the one or more OSCs do not exhibit significant expression of RARRES2. In some embodiments, the one or more OSCs express one or more genes selected from IGF2BP1 , IGF2BP2, and IGF2BP3. In some embodiments, the one or more OSCs express one or more genes selected from TGFB1 and TGFB2. In some embodiments, the one or more OSCs express one or more genes selected from STRA6, ERBB4, RARRES2, and EGFR. In some embodiments, the one or more OSCs express the gene BMP7. In some embodiments, the one or more OSCs express one or more genes selected from VEGFA and VEGFB. In some embodiments, the one or more OSCs express the gene PDGFA.

[0112] In some embodiments, the one or more OSCs express NR2F2. In some embodiments, the one or more OSCs include ovarian stroma cells. In some embodiments, the one or more OSCs include granulosa cells and ovarian stroma cells.

[0113] In some embodiments, the one or more OSCs include more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.

[0114] In some embodiments, the one or more OSCs are obtained by differentiation of a population of iPSCs. In some embodiments, the iPSCs are human iPSCs (hiPSCs). In some embodiments, the hiPSCs express or overexpress transcription factor RUNX2. In some embodiments, the hiPSCs express or overexpress transcription factor NR5A1 . In some embodiments, the hiPSCs express or overexpress transcription factor GATA4. In some embodiments, the hiPSCs express or overexpress transcription factor FOXL2.

[0115] In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and NR5A1 . In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2 and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors GATA4 and FOXL2.

[0116] In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , and GATA4. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, GATA4, and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors NR5A1 , GATA4, and FOXL2. In some embodiments, the hiPSCs express or overexpress transcription factors RUNX2, NR5A1 , GATA4, and FOXL2.

[0117] In some embodiments, the transcription factor expression or overexpression is under the control of doxycycline.

[0118] In some embodiments, the hiPSCs are contacted with a Wnt / p-catenin pathway activator. In some embodiments, the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof.

[0119] In some embodiments, at least one of the one or more OSCs are encapsulated. In some embodiments, the one or more OSCs are encapsulated in alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly-D-Lactone, or any mixture thereof. In some embodiments, the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof. In some embodiments, the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is laminin-521 . In some embodiments, the one or more OSCs are encapsulated in vitronectin.

[0120] In some embodiments, the one or more OSCs have lower expression, or undetectable expression, of one or more genes associated with pluripotency relative to an iPSC. In some embodiments, the one or more genes associated with pluripotency include NANOG. In some embodiments, the one or more genes associated with pluripotency include POU5F1 .

[0121] In some embodiments, at least some of the OSCs produce one or more growth factors. In some embodiments, the one or more growth factors include insulin-like growth factor (IGF), stem cell factor (SCF), epidermal growth factor (EGF), leukemia inhibitory factor (LIF), vascular endothelial growth factor (VEGF), bone morphogenetic proteins (BMPs), C-type natriuretic peptide (CNP), or any combination thereof. In some embodiments, at least a portion of the one or more growth factors is secreted.

[0122] In some embodiments, the one or more of the OSCs produce one or more steroids. In some embodiments, the one or more steroids include estradiol, progesterone, or a combination thereof. In some embodiments, the one or more steroids are produced in response to hormonal stimulation. In some embodiments, the hormonal stimulation comprises FSH, androstenedione treatment, or a combination thereof. In some embodiments, at least a portion of the one or more steroids is secreted.

[0123] In some embodiments, the one or more OSCs are cryopreserved. In some embodiments, the composition further includes an in vitro maturation (IVM) media. In some embodiments, the IVM media includes a cell culture media. In some embodiments, the IVM media includes Medicult-IVM media. In some embodiments, the IVM media includes one or more supplements. In some embodiments, the one or more supplements includes:

[0124] (i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL;

[0125] (ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;

[0126] (iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL; (iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;

[0127] (v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

[0128] In some embodiments, the one or more oocytes are retrieved from a donor subject. In some embodiments, the donor subject is from about 19 years old to about 45 years old. In some embodiments, the subject is undergoing ovarian stimulation. In some embodiments, the ovarian stimulation includes treatment with gonadotropin releasing hormone (GnRH). In some embodiments, the ovarian stimulation includes treatment with one or more GnRH analogs. In some embodiments, the one or more GnRH analog is a GnRH agonist or antagonist. In some embodiments, the ovarian stimulation includes one or more ovulatory triggers. In some embodiments, the one or more ovulatory triggers include human chorionic gonadotropin (hCG). In some embodiments, the one or more ovulatory trigger comprises a GnRH agonist, optionally wherein the GnRH agonist is leuprolide. In some embodiments, the ovarian stimulation includes FSH treatment. In some embodiments, the ovarian stimulation does not include FSH treatment. In some embodiments, the FSH treatment includes 300 international units (IU) to 700 IU of FSH. In some embodiments, the FSH treatment includes 400 IU to 600 IU of FSH. In some embodiments, the FSH treatment includes 1 , 2, 3, or more injections of FSH, optionally wherein the FSH treatment includes a plurality of injections, wherein each injection includes a dose of about 100 IU to about 200 IU of the FSH. In some embodiments, the ovarian stimulation further includes clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more doses, wherein each dose is between 50 mg and 150 mg (e.g., 50-75 mg, 60-80 mg, 75-100 mg, 90-115 mg, 110-130 mg, 125-150 mg; e.g., 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg). In some embodiments, the ovarian stimulation further includes one or more hCG triggers. In some embodiments, the one or more hCG triggers includes 2,500 IU to 10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose. In some embodiments, the one or more oocytes are in cumulus oocyte complexes (COCs). In some embodiments, the one or more oocytes include one or more denuded immature oocytes. In some embodiments, all of the one or more oocytes are denuded immature oocytes. In some embodiments, the one or more oocytes are not denuded.

[0129] In some embodiments, the one or more oocytes include one or more germinal vesicle (GV)- containing oocytes. In some embodiments, the one or more of the oocytes include one or more oocytes in metaphase I (Ml). In some embodiments, the one or more of the oocytes include one or more oocytes in metaphase II (Mil). In some embodiments, at least a portion of the one or more oocytes include one or more previously vitrified oocytes. In some embodiments, at least a portion of the one or more oocytes include one or more previously cryopreserved oocytes.

[0130] In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs.

[0131] In some embodiments, prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality. In some embodiments, the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

[0132] In some embodiments, the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs. In some embodiments, the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes. In some embodiments, the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

[0133] In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours. In some embodiments, the one or more oocytes are co-cultured with the one or more OSCs for about 24 hours to about 28 hours.

[0134] In some embodiments, the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

[0135] In some embodiments, the one or more oocytes are co-cultured in direct contact with the one or more OSCs. In some embodiments, the one or more oocytes do not directly contact the OSCs. In some embodiments, the culture system is a suspension culture. In some embodiments, the culture system is an adherent culture.

[0136] In some embodiments, the one or more oocytes are contacted with one or more mature sperm cells following the co-culture with the one or more OSCs. In some embodiments, the one or more oocytes comprise MH stage oocytes.

[0137] In some embodiments, the contact results in a higher fertilization rate. In some embodiments, the higher fertilization rate is higher than a fertilization rate resulting from contacting one or more oocytes with one or more mature sperm cells following a method of culturing oocytes in a culture that does not comprise the one or more OSCs. In some embodiments, the fertilization rate is about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher, as measured by the proportion of oocytes that are fertilized following the contact with the one or more mature sperm cells. In some embodiments, the fertilization rate is about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher, as measured by the proportion of oocytes that are fertilized following the contact with the one or more mature sperm cells. In some embodiments, the contact results in a greater high quality blastocyst formation rate as compared to a high quality blastocyst formation rate resulting from contacting one or more oocytes with one or more mature sperm cells following a method of culturing oocytes in a culture media that does not comprise the one or more OSCs. In some embodiments, the contact results in a higher euploid blastocyst formation rate as compared to a euploid blastocyst formation rate resulting from contacting one or more oocytes following a method of culturing oocytes in a culture media that does not comprise the one or more OSCs. In some embodiments, the blastocyst formation rate, high quality blastocyst formation rate, and / or euploid blastocyst formation rate is about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher, as measured by the proportion of oocytes that result in a blastocyst, high quality blastocyst, or euploid blastocyst following the contact with the one or more mature sperm cells. In some embodiments the fertilization rate and / or blastocyst formation rate (e.g., blastocyst formation rate, high quality blastocyst formation, and / or euploid formation rate) is determined via in vitro culturing methods comprising one or more oocytes, wherein the one or more oocytes are human oocytes or murine oocytes.

[0138] In some embodiments, the contact results in an embryo (e.g., an embryo that develops from a blastocyst, a high quality blastocyst, and / or a euploid blastocyst) that is suitable for implantation into the uterus of a subject. In some embodiments, the contact results in a higher likelihood of embryo implantation into the uterus of a subject. In some embodiments, the implantation of the embryo into the uterus of the subject results in a pregnancy. In some embodiments, the contacting results in a higher likelihood of pregnancy following embryo implantation into the uterus of a subject. In some embodiments, the subject sustains pregnancy for at least 28 weeks. In some embodiments, the subject sustains pregnancy for 28 weeks to 42 weeks (e.g., 28 weeks, 29 weeks, 30 weeks, 31 weeks, 32 weeks, 33 weeks, 34 weeks, 35 weeks, 36 weeks, 37 weeks, 38 weeks, 39 weeks, 40 weeks, 41 weeks, or 42 weeks). In some embodiments, the subject sustains pregnancy, and wherein the pregnancy results in a live birth of an infant. In some embodiments, the infant does not have a developmental abnormality and / or has an Apgar score that is 7 or higher.

[0139] In some embodiments, the subject undergoes fewer ovarian stimulation cycles as compared to culturing oocytes in a culture media that does not comprise the one or more OSCs.

[0140] In another aspect, the disclosure features a kit that includes any one of the preceding embodiments of the ex vivo composition and a package insert, wherein the package insert instructs a user of the kit to co-culture the population of ovarian support cells with one or more oocytes in accordance with any one of the preceding methods.

[0141] In another aspect, the disclosure features a kit that includes a vial that contains a population of iPSCs and a package insert, wherein the package insert instructs a user of the kit to differentiate the population of iPSCs to one or more ovarian support cells in accordance with any one of the preceding methods.

[0142] In another aspect, the disclosure features a kit that includes a vial that contains one or more OSCs and a package insert, wherein the package insert instructs a user of the kit to cultivate any one of the preceding embodiments of the cell culture system.

[0143] BRIEF DESCRIPTION OF THE DRAWINGS

[0144] The accompanying drawings are included to illustrate embodiments of the disclosure and further an understanding of its implementations.

[0145] FIG. 1 A is a series of micrographs showing representative images of the research-use only (RUO)-hiPSC expansion and transcription factor-induced ovarian support cell (OSC) differentiation process. Micrographs show the cells during the hiPSC expansion and days 1 and 5 (d1 and d5, respectively) of OSC differentiation. Scale bar is 250 pm. Below the images is a schematic of a timeline depicting the expansion and differentiation protocol.

[0146] FIG. 1B is a graph depicting flow cytometry analysis of CD82 expression in a control sample of undifferentiated hiPSCs and RUO-OSC-M differentiated cells. FIG. 1C is a series of UMAP projections and bar graphs depicting single cell RNA-sequencing (scRNA-seq) data obtained from six independent batches of hiPSCs after five days of differentiating with three inducible transcription factors: NR5A1 , RUNX2, and GATA4. The resulting gene expression profiles of the batches were partitioned into clusters based on granulosa cell markers (GC), the clusters including Early GC, GC, Atresia / luteolysis, Mitochondrial gene enriched, and Ribosomal gene enriched, and further partitioned into subclusters Early GC I, Early GC II, and Early GC III as well as GC I, GC II, and GC III.

[0147] FIG. 1D is a series of dot plots, depicting the expression of granulosa cell markers, pre-GC I and pre-GC II genes, and estradiol (E2)-related genes in accordance to each cluster. The scale represents mean expression in groups, ranging from 0 to 3, 0 to 1 .5, and 0 to 4, respectively. The circles represent fractions of cells in the indicated groups, ranging from 0 to 100%, 0 to 90%, and 0 to 100%, respectively.

[0148] FIG. 1E is a series of UMAP projections depicting the signature scores for genes corresponding to antral GC genes and pre-ovulatory GC genes. The color scale ranges from -0.1 to 0.2.

[0149] FIG. 1F is a stacked bar graph depicting the amount of each cluster type found in each lot. The overall percentages per group are shown to the right of the bar graph.

[0150] FIG. 2A is a schematic representation of the OSC-enhanced in vitro maturation (IVM) vs. media- only control IVM culture process.

[0151] FIG. 2B is a bar graph depicting the quantification of MH maturation rate in the control cultures and OSC co-cultured groups. RUO-OSC-M represents the combined maturation rates of three separate batches (lot 6, lot 8, and lot 56). Data is shown as mean ± SEM (p= 0.021 ; lot 6 v. control: 1 .37, lot 8 v. control: 1 .31 , lot 56 v. control: 1 .28).

[0152] FIG. 2C is a dot plot that depicts the expression of ligand-receptor related genes based on each cluster. The scale represents mean expression in groups, ranging from 0 to 2, and the circles represent fractions of cells in the indicated groups, ranging from 0 to 70%.

[0153] FIG. 2D is a dot plot that depicts the expression of growth factor-related genes based on each cluster. The scale represents mean expression in groups, ranging from 0 to 1 , and the circles represent fractions of cells in the indicated groups, ranging from 0 to 100%.

[0154] FIG. 3A is a schematic of the design of experiments (DOE) strategy for optimizing the hiPSC- derived OSC manufacturing process.

[0155] FIG. 3B is a bar graph depicting logworth values of DOE main effect results. The dashed line indicates p<0.01 .

[0156] FIG. 3C is a series of micrographs showing images of OSCs in cultures on day 5 of differentiation performed on a substrate of vitronectin or laminin-521 . Scale bar is 250 pm.

[0157] FIG. 3D is a graph showing flow cytometry analysis of CD82 expression in a control sample of undifferentiated hiPSCs, and OSCs differentiated on a vitronectin matrix (RUO-OSC-V) or a laminin-521 matrix (RUO-OSC-L).

[0158] FIG. 3E is a series of UMAP projections depicting gene clustering data of OSCs cultured on a vitronectin matrix (Vitronectin-OSC) (left) and OSCs cultured on a laminin-521 matrix (Laminin-OSC) (right).

[0159] FIG. 3F is a dot plot depicting the expression of granulosa cell markers in the vitronectin-OSC and laminin-OSC subsets. The scale represents mean expression in groups ranging from 0 to 3, and the circles represent the fraction of cells in the indicated group, ranging from 0 to 100%. FIG. 3G is a series of UMAP projections and a stacked bar graph depicting gene clustering data of individual batches of OSCs differentiated on a vitronectin matrix. The overall percentages per group are shown to the right of the bar graph.

[0160] FIG. 3H is a series of UMAP projections and a stacked bar graph depicting gene clustering data of individual batches of OSCs differentiated on a laminin-521 matrix. The overall percentages per group are shown to the right of the bar graph.

[0161] FIG. 4A is a bar graph comparing Mil maturation rates between media-only control groups and OSC co-culture groups. The maturation rates of three separate batches, (lots 41 and 49 manufactured on a vitronectin matrix and lot 86 manufactured on a laminin-521 matrix), are combined in the RUO-OSC-L / V bar, with additional bars depicting the individual maturation rates of each batch. Data is shown as the mean ± SEM (p=0.018; lot 41 / control: 1.08, lot 49 / control: 1.36, lot 86 / control: 1.27).

[0162] FIG. 4B is a graph depicting the relative MH maturation rates across OSC batches differentiated on different matrices selected from matrigel (M), vitronectin (V), and laminin-521 (L).

[0163] FIG. 4C is a series of dot plots depicting the expression of ligand-receptor genes in the RUO- OSC and laminin-OSC subsets. The scale represents mean expression in groups, ranging from 0 to 1 , and the circles represent the fraction of cells in the indicated group, ranging from 0 to 100%.

[0164] FIG. 4D is a series of dot plots depicting the expression of growth factor genes in the vitronectin- OSC and laminin-OSC subsets. The scale represents mean expression in groups, ranging from 0 to 1 , and the circles represent the fraction of cells in the indicated group, ranging from 0 to 100%.

[0165] FIG. 5A is an image of a gel depicting genotype data from a PCR reaction to assess the relative expression levels of transcription factors NR5A1 , GATA4, and RUNX2 from individual clones following hiPSC reprogramming.

[0166] FIG. 5B is a graph showing relative expression levels of ovarian support cell biomarkers and an hiPSC biomarker expressed in each indicated clone based on a cut-off (dotted line) as measured by flow cytometry.

[0167] FIG. 5C is a bar graph depicting the levels of estradiol (E2) secreted by the indicated clones in response to application of follicle stimulating hormone (FSH) (2), application of androstenedione (3), or application of a combination of FSH and androstenedione (4) to the cell culture media. E2 secretion in cells cultured in unsupplemented cell culture medium is also shown (1 ). Cells were cultured for 48 hours. Data is shown as the mean ± SEM.

[0168] FIG. 5D is a dot plot depicting the expression of granulosa cell markers in the indicated clones. The scale represents mean expression in groups, ranging from 0 to 1 , and the circles represent the fraction of cells in the indicated group, ranging from 0 to 100%.

[0169] FIG. 5E is a chart relative expression of OSC markers FOXL2 and CD82 as compared to the relative expression of hiPSC marker OCT4, cell viability, relative biomarker expression as shown as a percentage, and measured E2 secretion (pg / mL) of the nine indicated clones of manufactured OSCs.

[0170] FIG. 6A is a series of micrographs showing representative images of clinical grade (CG)-hiPSCs expansion and transcription factor-induced ovarian support cell (OSC) differentiation process on a matrix of laminin-521 . Micrographs show the cells during the hiPSC expansion and day 5 (d5) of OSC differentiation. Scale bar is 250 pm. Below the images is a schematic of a timeline depicting the expansion and differentiation protocol. FIG. 6B is a series of graphs showing flow cytometry analysis of OSC biomarkers FOXL2 and CD82 after differentiation depicted in FIG. 6A.

[0171] FIG. 6C is a series of graphs showing flow cytometry analysis of hiPSC biomarkers OCT4 and NANOG after differentiation depicted in FIG. 6A.

[0172] FIG. 6D is a UMAP projection of the clinical-grade (CG)-OSC subset.

[0173] FIG. 6E is a UMAP projection of the individual lots from the CG-OSC subset.

[0174] FIG. 6F is a stacked bar graph depicting the amount of each cluster type found in the indicated individual lots of the CG-OSC subset. Overall percentages per groups are shown to the right of the bar graph.

[0175] FIG. 6G is a dot plot depicting the expression of granulosa cell markers in the CG-OSC subset. The scale represents mean expression in groups, ranging from 0 to 2, and the circles represent the fraction of cells in the indicated group, ranging from 0 to 100%.

[0176] FIG. 6H is a gene ontology (GO) chord plot showing differentially regulated proteins in both RUO- OSCs and CG-OSCs as compared to hiPSCs.

[0177] FIG. 61 is a graph depicting the correlation curve for proteins detected in the secretome of RUO- OSCs as compared to CG-OSCs.

[0178] FIG. 7A is a bar graph comparing Mil maturation rates between media-only control groups and CG-OSC co-culture groups. The maturation rates of three separate batches, (lots 88, 90, and 116), are combined in the CG-OSC-L bar, with additional bars depicting the individual maturation rates of each batch. Data is shown as the mean ± SEM (p=0.019; lot 88 / control: 1 .24, lot 90 / control: 1 .22, lot 116 / control: 1.29).

[0179] FIG. 7B is a graph depicting the relative MH maturation rates of different individual batches of RUO-OSCs and CG-OSCs.

[0180] FIG. 7C is a dot plot depicting the expression of ligand-receptor genes in the CG-OSC subset. The scale represents mean expression in groups, ranging from 0 to 1 .5, and the circles represent fraction of cells in the indicated group, ranging from 0 to 100%.

[0181] FIG. 7D is a dot plot depicting the expression of growth factor-related genes in the CG-OSC subset. The scale represents mean expression in groups, ranging from 0 to 1 , and the circles represent fraction of cells in the indicated group, ranging from 0 to 100%.

[0182] FIG. 7E is a GO chord plot showing differentially regulated proteins in both RUO-OSCs and CG- OSCs after 24 hours of culture with a human oocyte as compared to the OSCs prior to culture.

[0183] FIG. 8A is a schematic diagram illustrating the study design for OSC-IVM in a murine oocyte maturation assay.

[0184] FIG. 8B is a bar graph showing the blastocyst formation rate following OSC-IVM in various test conditions. The first three conditions are the negative controls with no cells, inactivated cells, and alternative cells, respectively. The fourth condition is CG-OSCs with half the recommended amount of OSCs for OSC-IVM. Conditions five through seven represent OSC-IVM with RUO-OSCs, and the last three conditions represent OSC-IVM with CG-OSCs. A total of 120 COCs were evaluated in each condition.

[0185] FIG. 9A is a schematic diagram illustrating the stages of the phase I single-arm multi-center observational study to evaluate safety of the OSC-IVM method and subsequent embryo implantation following oocyte retrieval from patients that received a minimal follicular stimulation protocol. AMH: anti- Mullerian hormone; AFC: antral follicle count; NGS: next-generation sequencing; TE: trophectoderm; PGT-A: pre-implantation genetic testing for aneuploidy.

[0186] FIG. 9B is a schematic diagram illustrating the stages of the phase II comparative study comparing the efficacy of OSC-IVM and traditional media-only IVM methods and subsequent embryo implantation following oocyte retrieval from patients that received a minimal follicular stimulation protocol.

[0187] FIG. 10A is a bar graph showing the clinical outcomes (mean ± SEM) of a single arm, multi-site observational study following OSC co-culture for IVM. The percentages for outcomes were determined incrementally based on the number of samples that proceeded to each step.

[0188] FIG. 10B is a photograph of the first live birth of a healthy female baby following co-culture of an oocyte with a population of clinical grade OSCs in an OSC-IVM protocol and embryo implantation into a subject that received minimal follicular stimulation for oocyte retrieval.

[0189] FIG. 10C is a bar graph comparing clinical outcomes (mean ± SEM) following IVM co-culture with OSCs (OSC-IVM) versus traditional IVM culture in media alone (MediCult IVM). The outcomes were assessed based on the initial number of oocytes retrieved.

[0190] FIG. 10D is a graph comparing the results of both clinical studies comparing OSC-IVM and traditional media only IVM (MediCult IVM), wherein each data point represents the percentage of treatment cycles that led to successful completion of each outcome.

[0191] FIG. 11 A is a schematic of the experimental co-culture IVM approach. hiPSCs are differentiated using inducible transcription factor overexpression to form OSCs. Immature human cumulus oocyte complexes (COCs) are obtained from donors in the clinic after undergoing abbreviated gonadotropin stimulation. In the lab, embryology dishes are prepared including OSCs seeding as required, and COCs are introduced for IVM co-culture. Oocyte maturation and morphological quality are assessed after 24-28 hours IVM co-culture, and samples are banked for analysis or utilized for embryo formation.

[0192] FIG. 11B is a representative image of a co-culture setup at the time of plating containing human COCs (n=5) and 100,000 OSCs. Scale bar is 100 pm. COCs with expanded and unexpanded cumulus are seen with surrounding OSCs in suspension culture.

[0193] FIG. 12A shows the maturation rate of oocytes after 24-28 hour IVM experiments in Experiment 1 , including oocyte co-culture with OSCs, or in Media Control, n indicates the number of individual oocytes in each culture condition. Error bars indicate mean ± SEM. p-value is derived from unpaired t-test comparing OSC-IVM to Media Control condition.

[0194] FIG. 12B shows the Total Oocyte Score (TOS) generated from imaging analysis of MH oocytes after 24-28 hour IVM experiments, n indicates the number of individual Mil oocytes analyzed. Median (dashed line) and quartiles (dotted line) are indicated. An unpaired t-test indicated no significant (p = 0.2909) difference between the means. Due to low numbers of retrieved oocytes per donor, oocytes could not be consistently split between both conditions analyzed. Groups contain oocytes from predominantly non-overlapping donor cohorts and pairwise comparisons are not utilized.

[0195] FIG. 13A shows the maturation rate of oocytes after 28-hour IVM experiments in Experiment 2, including oocyte co-culture with OSCs or in Commercially available IVM Control, n indicates the number of individual oocytes in each culture condition. Error bars indicate mean ± SEM. p-value derived from paired t-test comparing Experimental OSC-IVM to Control Condition (Commercial IVM Control).

[0196] FIG. 13B shows the Total Oocyte Score (TOS) generated from imaging analysis of MH oocytes after 28-hour IVM experiments, n indicates the number of individual Mil oocytes analyzed. Median (dashed line) and quartiles (dotted line) are indicated. An unpaired t-test indicated no significant (p= 0.9420) difference between the means. COCs from each donor were randomly and equitably distributed between control and intervention to allow for pairwise statistical comparison.

[0197] FIG. 14A shows the embryo formation outcomes after 28-hour IVM experiments in the subset of oocytes utilized for embryo formation in Experiment 2, including oocyte co-culture with OSCs or in Commercially available IVM Control. Error bars indicate mean ± SEM. Results are displayed as a percentage of total COCs treated in the group. Outcomes for fertilization, cleavage, blastocyst formation, high quality blastocyst formation and euploid blastocyst formation are assessed for both IVM conditions.

[0198] FIG. 14B shows representative images of embryo formation in OSC-IVM versus Commercial IVM conditions at day 3 cleavage, as well as day 5, 6, and 7 of blastocyst formation. Embryos that were of suitable vitrification quality are labeled as “usable quality blast” and were utilized for trophectoderm biopsy.

[0199] FIG. 15A is a schematic of the experimental co-culture IVM approach. hiPSCs were differentiated using inducible transcription factor overexpression to form OSCs. Human oocytes were obtained from donors in the clinic after undergoing standard gonadotropin stimulation, and immature oocytes (GV and Ml) identified after denuding were allocated to this research study. In the embryology lab, dishes were prepared including OSCs seeding as required, and immature oocytes were introduced for IVM co-culture. Oocyte maturation and health were assessed after 24-28 hours IVM co-culture, and oocyte samples were banked for further analyses.

[0200] FIG. 15B is a representative image of co-culture setup at time of plating containing immature human oocytes (n=3) and OSCs. Scale bar is 200pm. Denuded GV oocytes are seen with surrounding OSCs in suspension culture.

[0201] FIG. 16A shows the maturation rate of oocytes after 24-28 hour IVM experiments, including oocyte co-culture with OSCs (OSC-IVM), or in Media Control (Media-IVM). n indicates the number of individual oocytes in each culture condition. Error bars indicate mean ± SEM. p-value derived from unpaired t-test comparing Experimental OSC-IVM to Control Media-IVM. Due to low numbers of retrieved oocytes per donor, each group contains oocytes from predominantly non-overlapping donor groups and pairwise comparisons are not utilized.

[0202] FIG. 16B shows Total Oocyte Scores (TOS) generated from imaging analysis of MH oocytes after 24-28 hour IVM experiments, n indicates the number of individual Mil oocytes analyzed. Median (dashed lines) and quartiles (dotted lines) are indicated. Unpaired t-test indicated no significant (ns, p=0.5725) difference between the means.

[0203] FIG. 17A shows representative images of Mil oocytes after 28-hour IVM co-culture with OSCs, stained with fluorescent alpha-tubulin dye to visualize the meiotic spindle. Blue lines transecting the middle of the PB1 and the spindle assembly from the oocyte center were used to derive the PB1 -spindle angle. PB1 -spindle angle ranges are indicated above. An example of an Mil with a missing spindle is provided from the Media-IVM condition.

[0204] FIG. 17B shows quantification of the angle between the PB1 and spindle, derived from oocyte fluorescence imaging analysis (as in FIG. 17A). n= indicates the number of individual oocytes analyzed from each condition. Number of Mil oocytes with no spindle assembly observed is also indicated below the axis labels. Median (dashed line) and quartiles (dotted line) are indicated. ANOVA statistical analysis found no significant difference (ns, p=0.1155) between the means of each condition. FIG. 18A shows UMAP projections of oocyte transcriptomes with symbols colored by experimental batch, experimental condition (OSC-IVM, Media-IVM, IVF-MII), oocyte maturation state, and Leiden cluster. Each symbol represents one oocyte. n=81 oocytes.

[0205] FIG. 18B shows UMAP projections colored by scores for each of the gene marker sets (GV and IVF Mil).

[0206] FIG. 18C shows UMAP projection generated from the scores of cells for each of the two signature marker sets (GV vs IVF MH), colored by experimental condition, oocyte maturation state, and Leiden cluster.

[0207] FIG. 18D shows quantification of oocytes in each maturation outcome (GV, Ml and MH) by experimental condition (IVM or IVF), with color distribution indicating percentage of population in each Leiden cluster. Striped bars are utilized to denote clusters with predominantly I VF-like characteristics.

[0208] FIG. 19A shows immunofluorescence images of human ovaroid (F66 / N.R1 .G.F #4 granulosa-like cells + hPGCLCs) sections at days 2, 4, 14, and 32 of culture, stained for FOXL2 (granulosa), OCT4 (germ cell / pluripotent), and DAZL (mature germ cell). Scale bars are 40 pm.

[0209] FIG. 19B shows mouse ovaroid (fetal mouse ovarian somatic cells + hPGCLCs) sections stained as in FIG. 18A. Scale bars are 40 pm.

[0210] FIG. 19C shows the fraction of OCT4+ and DAZL+ cells relative to the total (DAPI+) over time in human ovaroids and mouse xenovaroids. Counts were performed at 11 time points on images from 2 replicates of human ovaroids (F66 / N.R1 .G.F #4 and F66 / N.R2 #1 granulosa-like cells + hPGCLCs) and 1 replicate of mouse xeno-ovaroids.

[0211] FIG. 19D shows immunofluorescence images of human ovaroid (F66 / N.R2 #1 granulosa-like cells + hPGCLCs) sections at days 4 and 8 of culture, stained for SOX17 (germ cell), TFAP2C (early germ cell), and AMHR2 (granulosa). Scale bars are 40 pm.

[0212] FIG. 19E shows DAZL and OCT4 expression observed by immunofluorescence in day 16 ovaroids. Some DAZL+OCT4- cells (arrows) are visible, as well as DAZL+OCT4+ cells (arrows). Ovaroids are also beginning to form follicle-like morphology (arrows). Scale bars are 40 pm.

[0213] FIG. 20A shows day 35 human ovaroid (F66 / N.R1 .G #7 + hPGCLC) sections stained for FOXL2, OCT4, and AMHR2. Scale bars are 40 pm. Follicle-like structures are marked with triangles.

[0214] FIG. 20B shows a whole-ovaroid view of follicle-like structures in human ovaroids (F66 / N.R1 .G #7). Scale bars are 1 mm.

[0215] FIG. 20C shows a section of human ovaroid (F66 / N.R1 .G.F #4 + hPGCLC) at day 70 of culture, stained for FOXL2, NR2F2, and AMHR2, showing multiple small follicles (triangles) consisting single layers of FOXL2+AMHR2+ cells. NR2F2+ cells are interspersed between these. Scale bars are 100 pm.

[0216] FIG. 20D shows a section of human ovaroid (F66 / N.R2 #1 + hPGCLC) at day 70 of culture, stained for FOXL2, NR2F2, and AMHR2, showing an antral follicle consisting of FOXL2+AMHR2+ granulosa-like cells arranged in several layers around a central cavity. NR2F2 staining is visible outside of the follicle (marked ‘Stroma’). Scale bars are 100 pm.

[0217] FIG. 21 A shows the expression (Iog2 CPM) of selected granulosa (FOXL2), stroma / theca (NR2F2), and germ cell (PRDM1 ) markers. Expression is from scRNA-seq analysis of ovaroids (F66 / N.R1 .G.F #4 granulosa-like cells + hPGCLCs). Data from all samples (days 2, 4, 8, and 14) were combined for joint dimensionality reduction and clustering. FIG. 21 B shows Leiden clustering of four main clusters; the expression (Iog2 CPM) of marker genes is plotted for each cluster from the scRNA-seq analysis of ovaroids (as in FIG. 21 A).

[0218] FIG. 21 C shows the mapping of cells onto a human fetal ovary reference atlas (Garcia-Alonso et al., 2022) and assignment of cell types based on the scRNA-seq analysis described in (FIG. 21 A).

[0219] FIG. 21 D shows the proportion of somatic cell types, germ cells, DAZL+ cells, and DDX4+ cells in ovaroids from each day based on the scRNA-seq analysis described in (FIG. 21A).

[0220] FIG. 22A shows denuded oocytes from standard of care.

[0221] FIG. 22B shows COCs from minimal stimulation.

[0222] FIG. 22C shows OSC-IVM statistically significantly improves oocyte maturation rates.

[0223] FIG. 23A shows morphological quality of oocytes grown in culture with OSCs-lVM.

[0224] FIG. 23B shows the angle between the PB1 and the spindle of oocytes grown in culture with OSCs-lVM.

[0225] FIG. 23C shows the high similarity of oocytes grown in culture with OSCs-lVM to in vivo Mil oocytes.

[0226] FIG. 23D shows the high similarity of oocytes grown in culture with OSCs-lVM to in vivo Mil oocytes.

[0227] FIG. 24A shows the oocyte degradation rate from a toxicity assessment of OSCs-lVM product.

[0228] FIG. 24B shows the fertilization and blastocysts generation of OSCs-lVM product.

[0229] DEFINTIONS

[0230] Unless otherwise defined herein, scientific, and technical terms used herein have the meanings that are commonly understood by those of ordinary skill in the art. In the event of any latent ambiguity, definitions provided herein take precedent over any dictionary or extrinsic definition. Unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. The use of "or" means "and / or" unless stated otherwise. The use of the term "including," as well as other forms, such as "includes" and "included," is not limiting.

[0231] As used herein, the term “about” refers to a value that is within 10% (10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less) above or below the value being described. For instance, the phrase “about 50 mg” refers to a value between and including 45 mg and 55 mg.

[0232] As used herein, the term “assisted reproductive technology” or “ART” refers to a fertility treatment in which one or more female gametocytes (oocytes) or gametes (ova) are manipulated ex vivo so as to promote the formation of an embryo that can, in turn, be implanted into a subject in an effort to achieve pregnancy. For example, in some embodiments, an oocyte retrieved from a subject undergoing an ART procedure may be matured in vitro using, e.g., co-culturing methodologies described herein. In some embodiments, upon the formation of a mature oocyte (ovum), the ovum may be treated with one or more sperm cells so as to promote the formation of a zygote and, ultimately, an embryo. The embryo may then be transferred to the uterus of a female subject, for instance, using the compositions and methods in the art. Exemplary ART procedures include in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) techniques described herein and known in the art.

[0233] As used herein, the terms “subject” refers to an organism that receives treatment for a particular disease or condition as described herein. Examples of subjects and subjects include mammals, such as humans (e.g., a female human), receiving treatment for diseases or conditions that correspond to a reduced ovarian reserve or release of immature oocytes.

[0234] As used herein, the terms “controlled ovarian hyperstimulation” or more simply “ovarian stimulation” refers to a procedure in which ovulation is induced in a subject, such as a human subject, prior to oocyte or ovum retrieval for use in embryo formation, for instance, by in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Controlled ovarian hyperstimulation procedures may involve administration of follicle-stimulating hormone (FSH), human chorionic gonadotropin (hCG), and / or a gonadotropin-releasing hormone (GnRH) antagonist to the subject so as to promote follicular maturation. Controlled ovarian hyperstimulation methods are known in the art and are described herein as they pertain to methods for inducing follicular maturation and ovulation in conjunction with assisted reproductive technology.

[0235] As used herein, the term “derived from” in the context of a cell derived from a subject refers to a cell, such as a mammalian ovum, that is either isolated from the subject or obtained from expansion, division, maturation, or manipulation (e.g., ex vivo expansion, division, maturation, or manipulation) of one or more cells isolated from the subject. For instance, an ovum is “derived from” a subject or an oocyte as described herein if the ovum is directly isolated from the subject or obtained from the maturation of an oocyte isolated from the subject, such as an oocyte isolated from the subject from about 1 day to about 5 days following the subject receiving ovarian hyperstimulation procedures (e.g., an oocyte isolated from the subject from about 2 days to about 4 days following ovarian hyperstimulation procedures).

[0236] As used herein, the term “dose” refers to the quantity of a therapeutic agent, such as a follicle stimulating agent described herein, that is administered to a subject for the treatment of a disorder or condition, such as to enhance oocyte maturation and / or release and promote retrieval and ex vivo maturation of viable oocytes. A therapeutic agent as described herein may be administered in a single dose or in multiple doses. In each case, the therapeutic agent may be administered using one or more unit dosage forms of the therapeutic agent. For instance, a single dose of 100 mg of a therapeutic agent may be administered using, e.g., two 50 mg unit dosage forms of the therapeutic agent. Similarly, a single dose of 300 mg of a therapeutic agent may be administered using, e.g., six 50 mg unit dosage forms of the therapeutic agent or two 50 mg unit dosage forms of the therapeutic agent and one 200 mg unit dosage form of the therapeutic agent, among other combinations. Similarly, a single dose of 900 mg of a therapeutic agent may be administered using, e.g., six 50 mg unit dosage forms of the therapeutic agent and three 200 mg unit dosage forms of the therapeutic agent or ten 50 mg unit dosage form of the therapeutic agent and two 200 mg unit dosage forms of the therapeutic agent, among other combinations.

[0237] As used herein, the term “follicular triggering period” refers to the timepoint for administering a follicular triggering agent. The timepoint for administering a follicular triggering agent (i.e. , the follicular triggering period) to a female subject is on day 1 , day 2, or day 3 of her menstrual cycle, with preference for day 2 of her menstrual cycle. However, if the female subject is taking a hormonal contraceptive, then the timepoint for administering a follicular triggering agent is 4-6 days (e.g., 4 days, 5 days, or 6 days) after consuming the last oral contraception pill, with preference for 5 days following the dosing of her last oral contraception pill.

[0238] As used herein, the term “follicle-stimulating hormone” (FSH) refers to a biologically active heterodimeric human fertility hormone capable of inducing ovulation in a subject. FSH may be purified from post-menopausal human urine or produced as a recombinant protein product. Exemplary recombinant FSH products include follitropin alfa (GONAL-F, Merck Serono / EMD Serono) and follitropin beta (PUREGON / FOLLISTIM, MSD / Scherig-Plough).

[0239] As used herein, the term “human chorionic gonadotropin” (hCG) refers to the polypeptide hormone that interacts with the luteinizing hormone chorionic gonadotropin receptor (LHCGR) to induce follicle maturation and ovulation. hCG may be purified from the urine of pregnant women or produced as a recombinant protein product. Exemplary recombinant hCG products include choriogonadotropin alfa (OVIDREL®, Merck Serono / EMD Serono).

[0240] As used herein, the term “in vitro fertilization” (IVF) refers to a process in which an ovum, such as a human ovum, is contacted ex vivo with one or more sperm cells so as to promote fertilization of the ovum and zygote formation. The ovum can be derived from a subject, such as a human subject, undergoing various ARTs known in the art. For instance, one or more oocytes may be obtained from the subject following injection of follicular maturation stimulating agents for controlled ovarian hyperstimulation procedures, e.g., from about 1 day to about 5 days prior after injection of said agents (such as from about one day to about 4 days after injection of follicular maturation stimulating agents to the subject). The ovum may also be retrieved directly from the subject, for instance, by transvaginal ovum retrieval procedures known in the art.

[0241] As used herein, the term “intracytoplasmic sperm injection” (ICSI) refers to a process in which a sperm cell is injected directly into an ovum, such as a human ovum, so as to promote fertilization of the ovum and zygote formation. The sperm cell may be injected into the ovum, for instance, by piercing the oolemma with a microinjector so as to deliver the sperm cell directly to the cytoplasm of the ovum. ICSI procedures useful in conjunction with the compositions and methods described herein are known in the art and are described, for instance, in WO 2013 / 158658, WO 2008 / 051620, and WO 2000 / 009674, among others, the disclosures of which are incorporated herein by reference as they pertain to compositions and methods for performing intracytoplasmic sperm injection.

[0242] As used herein, the terms “ovum” and “oocyte” refer to a haploid female reproductive cell or gamete. In the context of assisted reproductive technology as described herein, ova may be produced ex vivo by maturation of one or more oocytes isolated from a subject undergoing ART. Ova may also be isolated directly from the subject, for example, by transvaginal ovum retrieval methods described herein or known in the art. Ovum or oocyte as used in this disclosure may refer to a plurality of oocytes. An oocyte may be in complex with surrounding cells such as a cumulus-oocyte complex (COC).

[0243] As used herein, the terms “mature ova” and “mature oocyte” refer to one or more ovum or oocyte in metaphase II (Mll)-stage of meiosis and typically has morphological or structural features consistent with metaphase II, such as a polar body and other features described herein.

[0244] As used herein, the terms “immature ovum” and “immature oocyte” refer to one or more ovum or oocyte that has not reached MH stage of meiosis. In some embodiments, an immature oocyte may be an oocyte including germinal vesicle (GV)-stage and / or metaphase I (Ml)-stage oocytes as determined by morphological features and / or other indications known in the art.

[0245] As used herein, the term “oocyte maturation” refers to the process by which an immature oocyte developmentally transitions to a mature oocyte. Oocyte maturation occurs as immature oocytes undergo cell signaling events incurred by external and internal stimuli. External stimuli may be produced by neighboring cells or supporting cells described herein. Oocyte maturation may occur prior to the release of an oocyte and retrieval from a subject. Oocyte maturation may occur in vitro as a result of culturing methods and culture compositions described herein.

[0246] As used herein, the term “maturation rate” refers to the proportion of oocytes (e.g., oocytes collected following an ovarian stimulation protocol) that are mature following in vitro or in vivo maturation. Oocyte maturation may be confirmed by determining that the oocyte has reached Mil stage of meiosis, e.g., via the methods of oocyte scoring described herein.

[0247] As used herein, the term “fertilization rate” refers to the proportion of oocytes (e.g., oocytes collected following an ovarian stimulation protocol and / or a method of in vitro maturation described herein) that are fertilized following contact with one or more mature sperm cells (e.g., via ICSI). A fertilization rate may be expressed as a fraction or percentage of fertilized oocytes in the total collection of oocytes (e.g., total number of oocytes in a particular sample such as a follicular aspirate sample collected from a subject). Methods of confirming oocyte fertilization are known in the art and include confirming the presence of two distinct pronuclei, e.g., via microscopy following oocyte and sperm contact.

[0248] As used herein, the term “blastocyst formation rate” refers to the proportion of oocytes (e.g., oocytes collected following an ovarian stimulation protocol and / or a method of in vitro maturation described herein) that form a blastocyst following contact with one or more mature sperm cells (e.g., via ICSI). A blastocyst formation rate may be expressed as a fraction or percentage of oocytes in the total collection (e.g., total number of oocytes in a particular sample such as a follicular aspirate sample collected from a subject) that form a blastocyst following contact with one or more mature sperm cells. A blastocyst is a distinctive structure that forms during mammalian embryonic development and is characterized by an inner cell mass and fluid-filled cavity (i.e., a blastocoel) that is surrounded by an outer layer of cells (i.e, a trophoblast).

[0249] As used herein, the term “high quality blastocyst formation rate” refers to the proportion of oocytes (e.g., oocytes collected following an ovarian stimulation protocol and / or a method of in vitro maturation described herein) that form a high quality blastocyst following contact with one or more mature sperm cells (e.g., via ICSI). A high quality blastocyst formation rate may be expressed as a fraction or percentage of oocytes in the total collection (e.g., total number of oocytes in a particular sample such as a follicular aspirate sample collected from a subject) that form a high quality blastocyst following contact with one or more mature sperm cells. A high quality blastocyst is assessed based on its development one that is determined to be more highly suitable for IVF based on expectations for successful pregnancy outcome. A high quality blastocyst is a blastocyst that is determined to have a score of 3CC or greater as determined by the Gardner blastocyst grading system.

[0250] As used herein, the term “euploid blastocyst formation rate” refers to the proportion of oocytes (e.g., oocytes collected following an ovarian stimulation protocol and / or a method of in vitro maturation described herein) that form a euploid blastocyst following contact with one or more mature sperm cells (e.g., via ICSI). A euploid blastocyst formation rate may be expressed as a fraction or percentage of oocytes in the total collection (e.g., total number of oocytes in a particular sample such as a follicular aspirate sample collected from a subject) that form a euploid blastocyst following contact with one or more mature sperm cells. A euploid blastocyst is a blastocyst that has the expected number of chromosomes for the particular species of blastocyst. For instance, a human euploid blastocyst has 46 chromosomes, and a murine euploid blastocyst has 40 chromosomes. Euploid blastocyst formation may be evaluated via a genetic test for aneuploidy (e.g., a preimplantation genetic test for aneuploidy (PGT- A)).

[0251] As used herein, an “induced pluripotent stem cell (iPSC)” such as a human iPSC (hiPSC) refers to one or more cells that are self-renewing in an undifferentiated state and can differentiate into any one type of differentiated cell types found in an organism. iPSCs can be derived from non-embryonic sources such as a somatic cell and can proliferate without limit. iPSCs can differentiate into each one of the three embryonic germ layers (i.e. , the endoderm, mesoderm, and ectoderm) and further cell types therein, depending on the induction of transcription factors and / or use of methods of gene editing known in the art. In one example, iPSCs can differentiate into a population of ovarian support cells, as described herein. The pluripotency or “stem-ness” of an iPSC may be verified by the expression of one or more pluripotent cell-specific markers including OCT4, SSEA3, SSEA4, TRA-1 -60, TRA-1 -81 , NANOG, SOX2, and / or POU5F1 , among other pluripotent cell-specific markers known in the art and described herein.

[0252] As used herein, an “ovarian support cell” (OSC) or “support cell” refers to one or more cells that promotes maturation of one or more oocytes. An OSC may be an ovarian granulosa cell (e.g., a type of granulosa cell described herein). Additionally or alternatively, an OSC may be an ovarian stroma cell (e.g., a type of stroma cell described herein). An OSC may form a cumulus-oocyte complex (COC) with an oocyte. An OSC may be generated from an exogenous source, such as from induced pluripotent stem cells (iPSCs), e.g., human induced pluripotent stem cells (hiPSCs), as described herein. An OSC may be applied to a retrieved oocyte using in vitro cell culture methods and compositions described herein. An OSC may be a mixture of two or more cell types. An OSC may be a mixture of stroma cells and granulosa cells such that the mixture is approximately a 1 :1 population of stroma cells and granulosa cells. An OSC may be a mixture of stroma cells and granulosa cells such that one cell type is in higher relative abundance compared to one or more cell types such that the mixture is approximately a 2:1 population, a 3:1 population, a 4:1 population, a 5:1 population, among other possible population distributions. An OSC may be a mixture of stroma cells and granulosa cells such that one cell type is more abundant in the mixture (e.g., 90% stroma cells and 10% granulosa cells, 80% stroma cells and 20% granulosa cells, 70% stroma cells and 30% granulosa cells, 60% stroma cells and 40% granulosa cells, 40% stroma cells and 60% granulosa cells, 30% stroma cells and 70% granulosa cells, 20% stroma cells and 80% granulosa cells, or 10% stroma cells and 90% granulosa cells, among other possible distributions). In some embodiments, an OSC may be a mixture of stroma cells and granulosa cells in combination with one or more additional cell types.

[0253] As used herein, an “ovarian stroma cell” or a “stroma cell” is a cumulus cell surrounding the oocyte to ensure healthy oocyte and subsequent embryo development. An ovarian stroma cell may form a COC with an oocyte. An ovarian stroma cell may express markers consistent with a stroma subtype such as nuclear receptor subfamily 2 group F member 2 (NR2F2), which can be detected by methods known in the art. An ovarian stroma cell may be a steroidogenic stroma cell. An ovarian stroma cell may be produced from differentiated hiPSCs as described herein.

[0254] As used herein, a “steroidogenic stroma cell” is a stroma cell that may produce one or more steroids such as estradiol, progesterone, or a combination thereof. One or more steroids may be produced in response to hormonal stimulation, such as by FSH, androstenedione, or a combination thereof. One or more steroids may be secreted. As used herein, the terms “EGFR” and “ERBB1 ” are interchangeable terms for a gene or a biomarker expressed by a cell (e.g., an ovarian support cell; (e.g., a differentiated iPSC)). EGFR and ERBB1 are gene names of epidermal growth factor receptor (e.g., human epidermal growth factor receptor; NCBI Gene ID: 1956). Other names for the gene are known in the art and include ERRP, HER1 , mENA, PIG51 , and NISBD2.

[0255] As used herein, an “ovarian granulosa cell” or a “granulosa cell” is a cumulus cell surrounding the oocyte to ensure healthy oocyte and subsequent embryo development. An ovarian granulosa cell may form a COC with an oocyte. An ovarian granulosa cell may express markers consistent with a granulosa subtype such as FOXL2, CD82 and / or follicle-stimulating hormone receptor (FSHR), which can be detected by methods known in the art. An ovarian granulosa cell may be a steroidogenic granulosa cell. An ovarian granulosa cell may be produced from differentiated hiPSCs as described herein.

[0256] As used herein, a “steroidogenic granulosa cell” is a granulosa cell that may produce one or more steroids such as estradiol, progesterone, or a combination thereof. One or more steroids may be produced in response to hormonal stimulation, such as by FSH, androstenedione, or a combination thereof. One or more steroids may be secreted.

[0257] As used herein, the term “biological sample” or “sample” may refer to a component of an in vitro cell culture system such as one or more isolated cells, a whole population of cells or a portion thereof, and / or cell culture media. Additionally, a biological sample or a sample may refer to a specimen (e.g., blood, blood component (e.g., serum or plasma), urine, saliva, amniotic fluid, cerebrospinal fluid, tissue (e.g., placental or dermal), pancreatic fluid, chorionic villus sample, hair, oocyte, ovum, and / or cells isolated from a subject.

[0258] As used herein, the term "express" refers to one or more of the following events: (1 ) production of an RNA template from a DNA sequence (e.g., by transcription); (2) processing of an RNA transcript (e.g., by splicing, editing, 5' cap formation, and / or 3' end processing); (3) translation of an RNA into a polypeptide or protein; and (4) post-translational modification of a polypeptide or protein. Expression of a gene or a biomarker of interest in a sample (e.g., a biological sample; e.g., a biological sample that comprises one or more iPSCs, OSCs, oocytes, or a combination thereof) can manifest, for example, by detecting: the quantity or concentration of mRNA encoding a corresponding protein (as assessed, e.g., using RNA detection procedures such as quantitative polymerase chain reaction (qPCR), reverse transcription PCR (RT-PCR), and RNA sequencing (RNA-seq) techniques, among other RNA detection methods known in the art), the quantity or concentration of a corresponding protein (as assessed, e.g., using protein detection methods described herein or known in the art, such as enzyme-linked immunosorbent assays (ELISA), immunofluorescence methods, Western blot, or mass spectrometry, among others), and / or the activity of a corresponding protein (e.g., in the case of an enzyme, as assessed using an enzymatic activity assay known in the art) in a sample. In any one of the preceding processes, the expression can increase or decrease relative to a control sample. In some embodiments, a control sample is a cell or population of cells that has not undergone one or more of the procedures that a sample of interest has undergone. Exemplary procedures include a reprogramming or differentiation method such as any one or more types of reprogramming or differentiation methods directed to an iPSC as described herein, an in vitro maturation method such as an in vitro maturation method directed to one or more oocytes as described herein, or an in vitro fertilization method such as an in vitro fertilization method described herein. In some embodiments, a control sample is a cell or a population of cells that is representative of a particular cell type, such as, an established cell line from a manufacturer or an otherwise characterized cell type (e.g., an iPSC or an OSC). In some embodiments, one or more cells are determined to express a gene or biomarker if the expression level is within an acceptable range as compared to the expression level of a control sample (e.g., within 20%, within 15%, within 10%, or within 5% of the expression level of a control sample). In some embodiments, significant expression refers to an expression level relative to a cut-off value or threshold, such as, e.g., a cut-off value or threshold for an RNA-sequencing or flow cytometry method. In some embodiments, a population of cells may be determined to express a gene or biomarker of interest if a significant portion of the population (e.g., about 50% of the population, about 60% of the population, about 70% of the population, about 80% of the population, about 90% of the population, about 95% of the population, or about 99% of the population) has significant expression of a gene or biomarker of interest by meeting or exceeding a particular cut-off or threshold.

[0259] In some instances, no significant expression of one or more target genes or biomarkers is observed. In some embodiments “no significant expression” or “no detectable expression” refers to an expression level that is below the limits of detection for a particular detection method (e.g., an RT-PCR or an ELISA) and / or an expression level that is less than about 95% (e.g., 95%, 96%, 97%, 98%, 99%, or less than 99%) relative to a suitable control, such as a particular cell type (e.g., an undifferentiated iPSC or a typical OSC such as an in vivo OSC). In some embodiments, “no significant expression” or “no detectable expression” refers to an expression level relative to a cut-off value or threshold, such as, e.g., a cut-off value or threshold for an RNA-sequencing or a flow cytometry method. No significant expression or no detectable expression may refer to the relative expression levels of a population of cells, in which a significant portion of the population (e.g., about 50% of the population, about 60% of the population, about 70% of the population, about 80% of the population, about 90% of the population, about 95% of the population, or about 99% of the population) does not have significant expression of a gene or biomarker of interest by having an expression level that is below a particular cut-off or threshold.

[0260] As used herein, the term “overexpress” refers to expression of a gene or a biomarker that is increased relative to a basal level of expression for a particular cell type (e.g., an iPSC). The expression of a gene or a biomarker may be increased by 5%, by 10%, by 15%, by 20%, by 25%, by 30%, by 35%, by 40%, by 45%, by 50%, by 55%, by 60%, by 65%, by 70%, by 75%, by 80%, by 85%, by 90%, by 95%, by 100%, or in some instances, greater than 100%, such as 125%, 150%, 175%, 200%, 225%, 250%, 275%, 300%, 325%, 350%, 375%, 400%, or greater than 400%. Overexpression of a gene or biomarker may be detected or measured by any suitable methods for detecting or measuring expression of a gene or a biomarker, such as genotyping methods, mRNA detection methods, or protein detection methods, such as methods described herein and known in the art.

[0261] As used herein, the term “doxycycline-responsive transcription regulatory element” refers to a nucleotide sequence such as a promoter that initiates transcription of a gene in the presence of doxycycline (e.g., an effective amount of doxycycline).

[0262] As used herein, the terms “oral contraceptive treatment,” “oral contraception,” “contraception,” or “birth control pill” refer to a hormonal method of treatment typically used to prevent pregnancy. Oral contraceptive treatment may block the release of oocytes from the ovaries and may contain hormones including estrogen and progestin. As used herein, the term “ovarian reserve” refers to the number of oocytes in a subject’s ovaries and the quality of said oocytes. The ovarian reserve naturally declines with age and / or medical conditions described herein. Subjects with a diminished ovarian reserve may seek IVF or other ARTs to achieve a successful pregnancy. Levels of anti-Mullerian hormone (AMH), as described herein, may be indicative of a subject’s ovarian reserve.

[0263] As used herein, the term “stimulation protocol” refers to the process of administering to the subject one or more follicular triggering agents during a follicular triggering period.

[0264] As used herein, the terms “follicular triggering agent” or “triggering agent” refer to a chemical or biological composition that stimulates release of oocytes from the ovaries during ovulation. Follicular triggering agents may include hormones such as human chorionic gonadotropin and follicle-stimulating hormone. As used herein, the term “induced pluripotent stem cells” (iPSCs) refer to artificial stem cells that derive from reprogrammed and otherwise manipulated harvested somatic cells. iPSCs may differentiate into other cell types including ovarian support cells or granulosa cells via methods known in the art and methods described herein. iPSCs may be human iPSCs (hiPSCs) or iPSCs from, e.g., other mammalian sources.

[0265] As used herein, the terms “Clomid” or “clomiphene citrate” are interchangeable terms that refer to a nonsteroidal, ovulatory stimulant that is designated chemically as 2-[p-(2-chloro-1 ,2- diphenylvinyl)phenoxy]triethylamine citrate (1 :1 ) with a molecular formula of C26H28CINO • CeHsO? and a molecular weight of 598.01 g / mol. Clomiphene citrate is a mixture of two geometric isomers in the cis (zuclomiphene) and trans (enclomiphene) forms, in which the mixture contains between 30% and 50% (e.g., about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, or about 55%) of the cisisomer (zuclomiphene).

[0266] As used herein, the term “cell culture” refers to laboratory methods that enable in vitro cell proliferation and / or cultivation of prokaryotic or eukaryotic cell types.

[0267] As used herein, the term “matrix” in the context of cell culture or methods of in vitro cell cultivation refers to a coating such as a substrate or a membrane on a surface of a cell culture receptacle (e.g., a well plate or a Petri dish) that facilitates immobilization or adhesion of a cell to the surface. A suitable matrix may be a protein such as a glycoprotein, a proteoglycan, or a combination thereof. A suitable matrix may derive from plants or animal products or may be synthetic (e.g., a recombinant protein or a polymer). A suitable matrix may be an extracellular matrix protein, a particular isoform thereof, or a purified or partially purified fraction that is enriched for species based on their molecular weight. A suitable matrix may comprise a mixture of components. Exemplary matrices include alginate, laminin (e.g., laminin-111 , laminin-21 1 , laminin-121 , laminin-221 , laminin-332, laminin-31 1 , laminin-321 , laminin- 41 1 , laminin-421 , laminin-51 1 , laminin-521 , and / or laminin-213), vitronectin (e.g., type I, type II, and / or type III), fibronectin (e.g., type I, type II, and / or type III), collagen (e.g., type I, type II, type III, type IV, type V, type VI, type VII, type VIII, type IX, type X, type XI, type XII, type XIII, type XIV, type XV, type XVI, type XVII, type XVIII, type XIX, type XX, type XXI, type XXII, type XIII, and / or type XXIV), chitosan, hyaluronic acid, Poly-D-Lactone, and hydrogels. Selection of a matrix may depend on cell type or relative cellular composition (e.g., lipid content, surface protein expression; e.g., relative abundance of one or more adhesion receptors).

[0268] As used herein, the term “encapsulate” or variations thereof refer to a coating of a cell or a plurality of cells in an in vitro culture system, optionally wherein the cell or plurality of cells is delivered (e.g., implanted, dispensed, or deposited) to a cellular niche (e.g., a tissue or an organ of an organism). Encapsulating a cell or a plurality of cells may increase the efficacy of delivery. A suitable reagent for encapsulation may be a protein such as a glycoprotein, a proteoglycan, or a combination thereof. A reagent for encapsulation may derive from plants or animal products or may be synthetic (e.g., a recombinant protein or a polymer). A suitable reagent for encapsulation may be an extracellular matrix protein, a particular isoform thereof, or a purified or partially purified fraction that is enriched for species based on their molecular weight. A suitable reagent for encapsulation comprise a mixture of components. Exemplary encapsulation agents include alginate, laminin (e.g., laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , and / or laminin-213), vitronectin (e.g., type I, type II, and / or type III), fibronectin (e.g., type I, type II, and / or type III), collagen (e.g., type I, type II, type III, type IV, type V, type VI, type VII, type VIII, type IX, type X, type XI, type XII, type XIII, type XIV, type XV, type XVI, type XVII, type XVIII, type XIX, type XX, type XXI, type XXII, type XIII, and / or type XXIV), chitosan, hyaluronic acid, Poly-D-Lactone, and hydrogels. Selection of a reagent for encapsulation may depend on cell type or relative cellular composition (e.g., lipid content, surface protein expression; e.g., relative abundance of one or more adhesion receptors) of the cells to be encapsulated or of the cells in a niche that will receive the one or more encapsulated cells.

[0269] As used herein, the term ‘Wnt / p-catenin activator” refers to any agent (e.g., a nucleic acid, a protein, a lipid, a small molecule, or a combination thereof) that ultimately upregulates, stimulates, initiates, drives, or induces activation of the Wnt / p-catenin signaling pathway. A Wnt / p-catenin activator may directly contact a positive regulator of the pathway to upregulate said pathway. A Wnt / p-catenin activator may directly contact a negative regulator of the pathway to upregulate said pathway (i.e. , act as an inhibitor of an inhibitor of the Wnt / p-catenin pathway). Regulators of the Wnt / p-catenin signaling pathway are known in the art and can be found elsewhere such as, e.g., Nusse and Clevers, Cell. 169(6):985-999, 2017, hereby incorporated by reference.

[0270] In some embodiments, a Wnt / p-catenin activator is a Rho-associated protein kinase (ROCK) inhibitor, such as Y-27642 or an equivalent salt or derivative thereof, the structure of which is shown below:

[0271] In some embodiments, a Wnt / p-catenin activator is a glycogen synthase kinase-3 inhibitor, such as CHIR099021 , or an equivalent salt or derivative thereof, the structure of which is shown below:

[0272] As used herein, the term “co-culture” refers to a type of cell culture method in which more than one cell type or cell populations are cultivated with some degree of contact between them. In a typical coculture system, two or more cell types may share artificial growth medium.

[0273] As used herein, the terms “adherent co-culture systems” or “adherent cell culture” refer to a cell culture arrangement by which cells are attached to a surface for proper growth and proliferation.

[0274] As used herein, the terms “suspension co-culture systems” or “suspension cell culture” refer to a cell culture arrangement by which cells are cultivated via dispersion in a liquid medium for proper growth and proliferation.

[0275] DETAILED DESCRIPTION

[0276] Described herein are compositions and methods for use in assisted reproductive technology (ART). For example, the compositions and methods described herein are directed to producing, engineering, and culturing one or more ovarian support cells (OSCs) (e.g., ovarian granulosa, ovarian stroma cells, or a combination thereof) and in vitro maturation of oocytes.

[0277] Advantageously, the compositions and methods described herein facilitate the harvest and use of previously discarded oocytes for purposes of in vitro fertilization (IVF) by performing in vitro maturation of immature oocytes via co-culture with ovarian support cells (e.g., ovarian support cells derived from reprogrammed iPSCs). The described in vitro maturation methods improve the ability to use these typically discarded immature oocytes in IVF procedures and may lead to a more cost-effective treatment strategy and reduced risk to a treated subject. For example, the methods can reduce the risk of systemic ovarian overstimulation for subjects seeking IVF procedures by requiring fewer hormone injections and / or lower doses of injected hormones than present IVF treatment options. Aspects of the present disclosure can be used to increase the overall pool of available healthy oocytes in women for use in IVF. Aspects of the present disclosure can also be used to significantly reduce hormone dosing in subjects during egg retrieval and improve oocyte quality in culture. This may greatly expand access to reproductive technology, make the duration of a single cycle significantly shorter, and require fewer cycles overall to achieve pregnancy.

[0278] I. Ex vivo compositions and cell culture media

[0279] In some embodiments, the disclosure provides an engineered cell culture system. In some embodiments, the engineered cell culture system comprises a population of engineered ovarian supporting cells (OSCs). In some embodiments, the subject matter described herein relates to a method of differentiating a population of induced pluripotent stem cells (iPSCs) such as human iPSCs (hiPSCs) to a population of OSCs. In some embodiments, the subject matter described herein relates to in vitro maturation (IVM) methods. In some embodiments, the engineered cell culture system promotes the maturation of one or more oocytes. In some embodiments, the subject matter described herein relates to in vitro fertilization (IVF) methods. In some embodiments, the one or more mature oocytes are utilized in an ART or IVF method. In some embodiments, the engineered cell culture system is an engineered cell co-culture system. In some embodiments, the co-cultured cells are in a suspension culture. In some embodiments, the co-cultured cells are in an adherent culture.

[0280] A. Ovarian support cells from human induced pluripotent stem cells

[0281] Any one or more OSCs utilized in the methods described herein may be created from iPSCs using transcription factor (TF)-directed protocols. In some embodiments, the iPSCs are mammalian iPSCs. In preferred embodiments, the iPSCs are human iPSCs (hiPSCs). In some embodiments, hiPSCs may be transformed with any one or more plasmids encoding one or more transcription factors. In some embodiments, the differentiation of hiPSCs to OSCs is driven by overexpression of one or more transcription factors. In some embodiments, the one or more TFs comprise FOXL2, NR5A1 , RUNX2, GATA4, or any combination thereof. In some embodiments, undifferentiated hiPSCs are reprogrammed using a transposase method (e.g., a piggyBac transposase method) to carry specific inducible transcription factors (e.g., FOXL2, NR5A1 , RUNX2, and / or GATA4). In some embodiments, hiPSCs may be transformed via electroporation, liposome-mediated transformation, viral-mediated gene transfer, among other cell transformation methodologies known in the art. In some embodiments, gene expression of desired transcription factors may be induced in a doxycycline-dependent manner. In some embodiments, a plasmid or expression vector used for reprogramming hiPSCs may have a reporter gene such as a fluorescent protein. In some embodiments, hiPSCs may differentiate into stroma cells with induced expression of transcription factors including GATA4, FOXL2, or a combination thereof. In some embodiments, hiPSCs may differentiate into granulosa with induced expression of transcription factors including FOXL2, NR5A1 , GATA4, RUNX1 , RUNX2, or a combination thereof. In addition to a combination of one or more transcription factors of FOXL2, NR5A1 , GATA4, RUNX1 , and / or RUNX2, hiPSCs may differentiate into granulosa via expression of KLF2, TCF21 , NR2F2, or a combination thereof.

[0282] The OSCs utilized in the methods described herein may be produced using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology. “CRISPR” is programmable technology that targets specific stretches of genetic code to edit DNA at precise locations. CRISPR technology may include CRISPR-CAS 9. Cas9 (or "CRISPR-associated protein 9") is an enzyme that uses CRISPR sequences as a guide to recognize and cleave specific strands of DNA that are complementary to the CRISPR sequence, allowing for the insertion of exogenous nucleic acids into a cell’s genome. For example, CRISPR-based gene editing techniques can be used to introduce into an iPSC genome, one or more genes encoding for factors that induce differentiation into OSCs (e.g., granulosa cells or stroma cells). These factors include, e.g., FOXL2, NR5A1 , GATA4, RUNX1 , and RUNX2.

[0283] Exemplary CRISPR systems include those that utilize a Cas9 enzyme. Cas9 enzymes, together with CRISPR sequences, form the basis of a technology known as CRISPR-Cas9 that can be used to edit genes within organisms. CRISPR technology may include Class 1 CRISPR systems including type I (cas3), type III (cas10), and type IV and 12 subtypes. CRISPR technology may include Class 2 CRISPR systems including type II (cas9), type V (cas12), type VI (cas13), and 9 subtypes. In some embodiments, CRISPR technology may involve CRISPR-Cas design tools which are computer software platforms and bioinformatics tools used to facilitate the design of guide RNAs (gRNAs) for use with the CRISPR / Cas gene editing system. For example, CRISPR-Cas design tools may include: CRISPRon, CRISPRoff, Invitrogen TrueDesign Genome Editor, Breaking-Cas, Cas-OFFinder, CASTING, CRISPy, CCTop, CHOPCHOP, CRISPOR, sgRNA Designer, Synthego Design Tool, and the like. CRISPR technology may also be used as a diagnostic tool. For example, CRISPR-based diagnostics may be coupled to enzymatic processes, such as SHERLOCK-based Profiling of in vitro Transcription (SPRINT). SPRINT can be used to detect a variety of substances, such as metabolites in subject samples or contaminants in environmental samples, with high throughput or with portable point-of-care devices.

[0284] In some embodiments, overexpression of the one or more TFs is driven by any suitable induction agent known in the art. In some embodiments, the induction lasts for 1 day, 2 days, 3, days, 4 days, 5 days or longer than 5 days. In some embodiments, transcription factors are constitutively expressed. In some embodiments, a plasmid or expression vector used for reprogramming hiPSCs may have a reporter gene such as a fluorescent protein. In some embodiments, the cells (e.g., hiPSCs) are treated with an agent that primes mesodermal induction. In some embodiments, during the initial induction of one or more transcription factors, cells (e.g., hiPSCs) are treated with an agent that activates Wnt / p-catenin signaling to prime cells for a mesodermal cell fate. In some embodiments, during the initial induction of one or more transcription factors, cells (e.g., hiPSCs) are treated with an agent that inhibits a serinethreonine protein kinase such as Rho-associated protein kinase (ROCK) (e.g., a small molecule ROCK inhibitor; e.g., Y-27642) or glycogen synthase kinase-3 (GSK3) (e.g., a GSK3 inhibitor; e.g., CHIR099021 ).

[0285] In some embodiments, the resulting OSCs comprise a population of cells with functional and biological similarity to human granulosa cells (cells that express FOXL2 and AMHR2, among other granulosa biomarkers known in the art and described herein). In some embodiments, the resulting OSCs comprise a population of cells with functional and biological similarity to ovarian stroma cells (cells that express NR2F2, among other stroma cell biomarkers known in the art and described herein). In some embodiments, the resulting OSCs comprise a population of cells comprising both granulosa and stroma cells. In some embodiments, a population of OSCs primarily comprises granulosa cells such that the population of OSCs comprise more than 50%, more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells. Reprogramming of hiPSCs to granulosa may be determined by genotyping methods described herein.

[0286] Differentiation of hiPSCs to OSCs (such as granulosa cells) may be determined by relative expression of biomarkers typical of a granulosa cell type including FOXL2, AMHR2, CD82, FSHR, IGFBP7, KRT19, STAR, WNT4, or a combination thereof among other granulosa cell biomarkers known in the art. hiPSCs that are differentiated to OSCs (such as granulosa cells) may be categorized into one or more clusters based on transcriptome profiling. In some embodiments, differentiation of hiPSCs to OSCs (such as granulosa cells) may be determined by relative expression of biomarkers or genes, such as genes associated with cell adherence, chemotaxis, growth factors and / or growth factor receptors, steroids and / or steroid receptors, or a combination thereof, among other genes or biomarkers associated with one or more types of OSCs. Differentiation of hiPSCs to OSCs may be determined by relative expression of biomarkers typical of an OSC (e.g., a granulosa cell), including GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and / or ITGB. In some embodiments, biomarkers typical of an OSC may include BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and / or CD46. In some embodiments, biomarkers typical of an OSC may include expression of EFNB2, TGFBR1 , BMPR2, NOTCH2, and NOTCH3. In some embodiments, biomarkers typical of an OSC may include HES1 , KITLG, NOTCH3, and / or ID3. In some embodiments, biomarkers typical of an OSC may include FGF2, TGFB1 , and / or BMP7. In some embodiments, biomarkers typical of an OSC may include CDH2 and / or NOTCH2, with no significant expression of RARRES2. In some embodiments, biomarkers typical of an OSC may include IGF2BP1 , IGF2BP2, and / or IGF2BP3. In some embodiments, biomarkers typical of an OSC may include TGFB1 and / or TGFB2. In some embodiments, biomarkers typical of an OSC may include FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and / or ERBB4. In some embodiments, biomarkers typical of an OSC may include RARRES2, NOTCH2, NOTCH3, ID3, and / or BMPR2. In some embodiments, biomarkers typical of an OSC may include STRA6, ERBB4, RARRES2, and / or EGFR. In some embodiments, biomarkers typical of an OSC may include BMP7. In some embodiments, biomarkers typical of an OSC may include VEGFA and / or VEGFB. In some embodiments, biomarkers typical of an OSC may include PDGFA. In some embodiments, the functional screening of individual clones identifies a stable line harboring the optimal balance of expression of each transcription factor or biomarker.

[0287] In some embodiments, application of doxycycline to the cells or cell culture maintains activation of one or more TFs in the OSCs (e.g., for doxycycline-dependent induction).

[0288] Expression of one or more genes, transcription factors, and / or biomarkers may be detected or measured by methods of protein and / or mRNA expression that are routine in the art. Exemplary methods of detecting or measuring the relative expression of one or more transcription factors or biomarkers include flow cytometry, RNA-sequencing (RNA-seq) (e.g., single-cell RNA-seq), real-time reverse transcription polymerase chain reaction (RT-PCR), quantitative PCR (qPCR), RT-qPCR, Northern blot analysis, mass spectrometry and proteomic modalities, Western blot analysis, enzyme-linked immunosorbent assay (ELISA), immunofluorescence or immunodetection methods, among other detection methods known in the art.

[0289] In some embodiments, reprogramming of hiPSCs to OSCs yield one or more OSCs that share strong gene expression similarity to in vivo granulosa cells (e.g., cells that express FOXL2 and AMHR2) In some embodiments, the OSCs share strong gene expression similarity to in vivo stroma cells (e.g., cells that express NR2F2). In some embodiments, the OSCs recapitulate folliculogenesis progression in vitro through follicle formation. In some embodiments, reprogramming of hiPSCs to one or more OSCs may be determined by production of growth factors and / or hormones that may adequately support in vitro maturation of retrieved oocyte via paracrine and juxtacrine cell signaling. In some embodiments, the OSCs produce one or more growth factors including insulin-like growth factor (IGF), stem cell factor (SCF), epidermal growth factor (EGF), leukemia inhibitory factor (LIF), vascular endothelial growth factor (VEGF), platelet derived growth factor (PDGF), bone morphogenetic proteins (BMPs), C-type natriuretic peptide (CNP), or any combination thereof. In some embodiments, the one or more growth factors are secreted from the OSCs. In some embodiments, the OSCs are steroidogenic and produce hormones including estradiol and / or progesterone. In some embodiments, the OSCs are steroidogenic in the presence of an exogenously supplied reagent. In some embodiments, the OSCs such as granulosa cells produce estradiol and / or progesterone upon stimulation of androstenedione and FSH or forskolin. In some embodiments, secretion of estradiol and / or progesterone may be detected or measured by one or more protein detection methods known in the art. In some embodiments, application of doxycycline to the OSCs maintains cell identity and drives steroidogenic activity. In some embodiments, doxycycline is applied to the OSCs or OSC media upon thawing and seeding OSCs derived from reprogrammed iPSCs after cryopreservation and frozen storage (e.g., for doxycycline-dependent induction).

[0290] B. Cell culture media

[0291] OSCs derived from iPSCs (e.g., hiPSCs) or transgenic OSCs may be provided as a composition further containing a cell culture media. Said OSCs or precursors (e.g., hiPSCs prior to reprogramming) may be cultivated in a cell culture media. In some embodiments, the engineered OSCs can be added to a commercially available reproductive media (e.g., IVF, IVM, (e.g., MEDICULT IVM® media), or LAG media). In some embodiments, cell culture media comprises DMEM / F12 supplemented with Knockout Serum Replacement (KSR). In some embodiments, the cell culture media comprises L-glutamine analogs such as, e.g., GLUTAMAX™ (GIBCO™, Thermo Fisher Scientific, Waltham, MA), optionally wherein the GLUTAMAX™ has been adapted to use animal origin-free reagents. In some embodiments, an embryology lab procures a suitable IVF cell culture media. In some embodiments, the cell culture media comprises Medicult IVM media. In some embodiments, an embryology lab procures a suitable cell culture plate. In some embodiments, the cell culture plate is a GPS Universal dish. In some embodiments, an embryology lab procures an ART-grade mineral oil. In some embodiments, the co-culture is achieved by preparation of an IVM media. In some embodiments, the IVM media comprises a base medium formulation. In some embodiments, the base medium formulation comprises MEDICULT IVM® media.

[0292] In some embodiments, the hiPSCs and / or the resulting OSCs described herein are cultured on a matrix or encapsulated during induction, culturing, or co-culturing with an oocyte. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising alginate. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising laminin. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising laminin-521 . In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising vitronectin. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising collagen. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising chitosan. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising hyaluronic acid. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in a matrix comprising dextran hydrogel. In some embodiments, the hiPSCs and / or the OSCs are cultured on a matrix or encapsulated in matrix comprising a MATRIG EL® matrix.

[0293] In some embodiments, the cell culture media is supplemented. The cell culture media may be supplemented with human serum albumin (HSA) (e.g., at about 5-15 mg / mL, e.g., 10 mg / mL), follicle stimulating hormone (FSH) (e.g., at about 70-80 mIU / mL, e.g., 75 mIU / mL), human chorionic gonadotropin (hCG) (e.g., at about 95-105 mIU / mL, e.g., 100 mIU / mL), androstenedione (e.g., at about 495-505 ng / mL, e.g., 500 ng / mL), doxycycline (e.g., 0.5-1 .5 pg / mL, e.g., 1 pg / mL) and other compounds such as hyaluronidase and / or dPBS. In some embodiments, one or more supplemented proteins are recombinant proteins. In some embodiments, the cell culture media is supplemented with an agent that that activates Wnt / p-catenin signaling, such as, e.g., a ROCK inhibitor or a GSK3 inhibitor. In some embodiments, the supplemented cell culture media forms an in vitro maturation (IVM) media. In some embodiments, the IVM media is utilized by placement of about 100 pL of the media into the suitable cell culture dish, with a mineral oil overlay the day before oocyte retrieval from a subject. In some embodiments, about 2 to about 4 hours prior to IVM culture, the engineered OSCs are thawed. In some embodiments, the thawed engineered OSCs are centrifuged. In some embodiments, the engineered OSCs are washed with IVM media. In some embodiments, the engineered OSCs are seeded to a cell culture droplet. In some embodiments, the engineered OSCs are seeded at a final concentration of about 1 ,000 cells per 1 pl (e.g., about 500-1 ,000 cells / pL, about 700-1 ,000 cells / pL, about 1 ,000-1 ,200 cells / pL, about 1 ,000-1 ,500 cells / pL, or about 1 ,000-2,000 cells / pL).

[0294] C. Production and storage of ovarian support cells

[0295] In some embodiments, one or more OSCs described herein may be produced in multiple batches. In some embodiments, the OSCs may be frozen and thawed prior to co-culture methods. In some embodiments, the OSCs are freshly reprogrammed from a population of iPSCs prior to an in vitro maturation method. In some embodiments, the OSCs may be seeded and equilibrated for 2-8 hours (e.g., 2-3 hours, 2-4 hours, 3-4 hours, 4-6 hours, 5-7 hours, 6-8 hours; e.g., 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours) before the addition of oocytes for in vitro maturation. In some embodiments, the OSCs may be seeded and equilibrated for about 25-90 minutes (e.g., about 25 minutes, about 30 minutes, about 35 minutes, about 40 minutes, about 45 minutes, about 50 minutes, about 55 minutes, about 60 minutes, about 65 minutes, about 70 minutes, about 75 minutes, about 80 minutes, about 85 minutes, or about 90 minutes).

[0296] In some embodiments, a subject may donate hiPSCs. hiPSCs donation may follow an oocyte retrieval process as discussed herein. A subject participating in hiPSCs donation may be different, or the same, from the subject from which the oocyte was retrieved. In some embodiments, a hiPSC donor may undergo a stimulation protocol as disclosed herein. Select hiPSC clones may be expanded to generate an intermediate cell bank. Select hiPSC clones may be expanded and fully differentiated for immediate use.

[0297] In some embodiments, the hiPSCs (e.g., undifferentiated hiPSCs; e.g., intermediate cell banks) or the engineered OSCs described herein are provided in a cryovial. In some embodiments, the cryovial is composed of -125,000 cells (e.g., hiPSCs or OSCs). In some embodiments, the hiPSCs or the engineered OSCs are suspended in a cryoprotectant solution. In some embodiments, the cryoprotectant solution comprises CryoStor CS10. In some embodiments, the cryovial is a plastic vial. In some embodiments, the cryovial is an internal thread liquid nitrogen-suited plastic vial. In some embodiments, the hiPSCs or the engineered OSCs are provided in one or more aggregates. In some embodiments, the hiPSCs or the engineered OSCs are provided in one or more single cell suspensions.

[0298] In some embodiments, the hiPSCs or the engineered OSCs (e.g., OSCs produced from reprogrammed hiPSCs) are prepared and then frozen or cryopreserved for later use. Cryopreservation or freezing methods may include using a cryoprotective agent such as dimethyl sulfoxide and / or any other freezing method known in the art. In some embodiments, the hiPSCs or the engineered OSCs are stored in liquid nitrogen. In some embodiments, the hiPSCs or the engineered OSCs are stored in liquid nitrogen until use. In some embodiments, cryopreserved undifferentiated hiPSCs (e.g., intermediate cell banks) are stored in liquid nitrogen. Undifferentiated hiPSCs (e.g., intermediate cell banks) can be thawed for further differentiation steps. In some embodiments, the engineered OSCs are stored in liquid nitrogen until use for IVM methods and applications.

[0299] In some embodiments, frozen cells are submitted to different sets of batch release assays, in which cells undergo one or more tests to determine cell quality. In some embodiments, one or more aliquots of frozen cells undergo a panel of tests to determine cell count and / or viability upon thawing, to verify genetic stability, to verify genotype, to confirm sterility, or a combination thereof. One or more aliquots of undifferentiated cells (e.g., undifferentiated hiPSCs; e.g., an intermediate cell bank) may further undergo a panel of tests to measure the presence and / or relative abundance of one or more pluripotency markers (e.g., NANOG, POU5F1 , SOX2, and / or OCT4). One or more aliquots of one or more OSC populations (e.g., final target cell banks) may undergo a panel of tests to measure the presence and / or relative abundance of a marker associated with one or more types of OSCs (e.g., a granulosa or a stroma cell) or the potency of secreted proteins or steroids (e.g., estradiol and / or progesterone production). In further embodiments, one or more aliquots of frozen cells undergo tests to determine risks of embryo toxicity (e.g., the presence of one or more chemicals or agents that may disrupt normal growth, development, or genetic differentiation of an embryo).

[0300] D. Ovarian support cells and oocytes for in vitro maturation

[0301] In some embodiments, the one or more oocytes are human oocytes. In some embodiments, the one or more oocytes are mammalian oocytes. In some embodiments, the one or more oocytes are mouse oocytes. In some embodiments, the one or more oocytes are rat oocytes. In some embodiments, the one or more oocytes are monkey oocytes. In some embodiments, the one or more oocytes are rhesus macaque oocytes. In some embodiments, the one or more oocytes is obtained from conventional stimulation.

[0302] In some embodiments, the engineered OSCs promote the maturation of one or more oocytes outside of the body (i.e. , in vitro maturation (IVM)) by forming a cumulus-oocyte-complex (COC) with one or more oocytes. In some embodiments, the one or more oocytes may be evaluated at any point during IVM based on oocyte scoring, as described in Section II l(C)(i). In some embodiments, the engineered OSCs widen access to in vitro fertilization (IVF) and oocyte freezing by offering a more cost-effective, more efficient, and less invasive methodology for subjects seeking fertility treatments or an ART.

[0303] In some embodiments, the engineered OSCs promote IVM of one or more oocytes, as describe in further detail in Section III. In some embodiments, the engineered OSCs do not have any continuing effect (e.g., biological or developmental effect) on the one or more mature oocytes following maturation. In some embodiments, the engineered OSCs are physically separated from the one or more mature oocytes after the IVM and are not present in a sample utilized in a further step of an IVF procedure (e.g., embryo formation and / or embryo implantation). In some embodiments, the one or more mature oocytes are utilized for subsequent IVF procedures including, but not limited to, embryo formation and embryo implantation. In some embodiments, the engineered OSCs are not separated from the one or more matured oocytes and have no biological or developmental impact on a developing embryo. In some embodiments, the developing embryo derived from a matured oocyte (e.g., an Mil stage oocyte) that was matured by co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of engineered OSCs has no detectable residual OSCs. In some embodiments, residual OSCs may be detected by RNA-seq, e.g., by measuring the expression of one or more gene signatures (e.g., a gene signature described herein) characteristic of an engineered OSC.

[0304] II. Methods of stimulating oocyte release

[0305] The methods described herein may be indicated for a subject who desires to increase the number of usable oocytes from any standard ART that utilizes controlled ovarian hyperstimulation (COH). The increased number of usable oocytes can result from co-culturing immature oocytes with one or more OSCs (e.g., one or more reprogrammed OSCs as described herein) to promote maturation of the immature oocytes that are commonly obtained in typical COH and oocyte retrieval procedures. Current standard of care is to discard retrieved immature oocytes. The OSCs described herein can promote maturation of immature oocytes, thus increasing the number of mature and usable oocytes from a population of retrieved oocytes.

[0306] Additionally, the methods described herein may be indicated for a subject seeking assisted reproductive technology procedures but may have limited access due to prohibitively high costs and / or risks associated with traditional methods of ovarian stimulation for oocyte retrieval (e.g., risks of ovarian hyperstimulation syndrome (OHSS)). Traditional methods typically require administering gonadotropins to a subject for ovarian stimulation and retrieval of mature oocytes. Delivery of administered gonadotropins is typically inefficient and requires high concentrations of gonadotropins to ensure that sufficient levels of gonadotropins are delivered to the ovarian follicle for oocyte maturation and release following systemic injection. By performing IVM methods described herein, reduced quantities of gonadotropin can be administered for oocyte retrieval, thereby providing a method that circumvents the costly and potentially dangerous side effects associated with systemic administration of high levels of gonadotropins. Immature oocytes can be retrieved, exposed to conditions that lead to optimized maturation ex vivo, and the resulting mature oocytes can be used for subsequent fertilization, embryo development, blastocyst formation, implantation, and gestation to ultimately become healthy offspring.

[0307] A. Subject selection

[0308] The methods of stimulating oocyte release described herein are directed to a subject seeking IVF treatment options. In general, a subject is a female with a low oocyte retrieval number or a subject with many immature oocytes. A subject may be between 20 and 45 years old, and a subject is typically 35 years of age or older. A subject may have a reduced ovarian reserve due to advancing age and / or a genetic or medical condition (e.g., polycystic ovarian syndrome (PCOS)) that leads to a reduced ovarian reserve. A subject may have an ovarian reserve of 20 or fewer oocytes such that a subject has 1 to 5 oocytes, 4 to 10 oocytes, 8 to 16 oocytes, or 15 to 20 oocytes, e.g., the subject has 1 oocyte, 2 oocytes, 3 oocytes, 4 oocytes, 5 oocytes, 6 oocytes, 7 oocytes, 8 oocytes, 9 oocytes, 10 oocytes, 11 oocytes, 12 oocytes, 13 oocytes, 14 oocytes, 15 oocytes, 16 oocytes, 17 oocytes, 18 oocytes, 19 oocytes, or 20 oocytes. A subject may have anti-Mullerian hormone (AMH) levels that are consistent with reduced ovarian reserve. A subject may have their AMH levels measured by a blood test and other methods known in the art. A subject may have AMH levels between 1 and 6 ng / mL (e.g., 1 -2 ng / mL, 2-4 ng / mL, or 4-6 ng / mL; e.g., 1 ng / mL, 2 ng / mL, 3 ng / mL, 4 ng / mL, 5 ng / mL, or 6 ng / mL). A subject may have measured estradiol levels between 20 and 50 pg / mL (e.g., 20-30 pg / mL, 25-35 pg / mL, 30-40 pg / mL, 35- 45 pg / mL, or 40-50 pg / mL; e.g., 20 pg / mL, 21 pg / mL, 22 pg / mL, 23 pg / mL, 24 pg / mL, 25 pg / mL, 30 pg / mL, 35 pg / mL, 40 pg / mL, 45 pg / mL, or 50 pg / mL).

[0309] A physician or skilled practitioner may evaluate a subject for the methods of stimulating oocyte release by taking a biological sample from the subject. A biological sample may include a laboratory specimen held by a biorepository for research. In some embodiments, a biological sample may include bodily fluids including blood, saliva, urine, semen (seminal fluid), vaginal secretions, cerebrospinal fluid (CSF), synovial fluid, pleural fluid (pleural lavage), pericardial fluid, peritoneal fluid, amniotic fluid, saliva, nasal fluid, optic fluid, gastric fluid, breast milk, cell culture supernatants, and the like. A biological sample may include a medical diagnosis, user input describing how a user is feeling and / or a symptomatic complaint, information collected from a wearable device pertaining to a user and the like. For example, a biological sample may include information obtained from a visit with a medical professional such as a health history. In yet another non-limiting example, a biological sample may include information such as data collected from a wearable device worn by a user and designed to collect information relating to a user’s sleep patterns, exercise patterns, and the like. In an embodiment, a biological sample collected at a particular date and / or time of a user’s menstrual cycle. For instance, and without limitation, a biological sample may be collected on the second day of a user’s menstrual cycle to evaluate one or more hormone levels. The biological sample may be utilized to determine markers of a subject’s ovarian reserve that may be measured by a subject’s AMH levels and / or other hormone levels or other indications. AMH levels of 1 ng / mL or less may be used to indicate a low ovarian reserve. A subject with a low ovarian reserve may have measured AMH levels of 1 .0 ng / mL, 0.9 ng / mL, 0.8 ng / mL, 0.7 ng / mL, 0.6 ng / mL, 0.5 ng / mL, 0.4 ng / mL, 0.3 ng / mL, 0.2 ng / mL, or 0.1 ng / mL. Other biological samples that may be utilized to determine one or more markers of a subject’s overall health include without limitation menstrual cycle progression, and / or monitor circulating hormone levels such as estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4), estrone (E1 ), estriol (E3), testosterone, androgens, dehydroepiandrosterone (DHEA), triiodothyronine (T3), tetraiodothyronine (T4), calcitonin, melatonin, insulin, cortisol, human growth hormone (HGH), adrenaline levels, and other hormones.

[0310] Other biological sample data taken from a subject includes at least an oocyte. As used in this disclosure, “biological sample data” is data that provides a characterization of the biological, genetic, biochemical and / or physiological properties, compositions, or activities of biological samples. In some embodiments, an oocyte may be an immature oocyte. An “immature oocyte” as used in this disclosure is a one or more immature reproductive cells originating in the ovaries. In some embodiments, an immature oocyte may be an oocyte including GV and / or Ml oocytes. In some embodiments, an immature oocyte may be a plurality of oocytes. An immature oocyte may be immature cumulus-oocyte complexes (COCs) taken from the subject. As used in this disclosure, a “cumulus-oocyte complex” is an oocyte surrounded by specialized granulosa cells. As used in this disclosure, a “specialized granulosa cell” is a cumulus cell surrounding the oocyte to ensure healthy oocyte and embryo development. In some embodiments, the immature oocyte may contain an oocyte wherein the specialized granulosa cell is added to mature the oocyte in a cell culture (e.g., a co-culture) and thus create a COC.

[0311] In some embodiments of the method, the biological sample may be extracted from the user through an extraction device. An “extraction device” is a device and / or tool capable of obtaining, recording and / or ascertaining a measurement associated with a sample. The extraction device may include a needle, syringe, vial, lancet, Evacuated Collection Tubes (ECT), tourniquet, vacuum extraction tube systems, any combination thereof and the like. For example, the extraction device may comprise a butterfly needle set. Data from a biological sample may include measurements, for example, of serum calcium, phosphate, electrolytes, blood urea nitrogen and creatinine, uric acid, and the like.

[0312] In an embodiment of the method, biological sample information of a subject may be obtained from an ultrasound. An “ultrasound,” as used in this disclosure, is any procedure that utilizes sound waves to generate one or more images of a user’s body. For example, an ultrasound may be utilized to obtain an image of a subject’s reproductive organs and / or tissues. In an embodiment, an ultrasound may be performed at a particular time of a subject’s menstrual cycle. For example, a subject may receive an ultrasound on day 2 of her cycle and this may be utilized to determine follicle size and / or follicle count. Selection of a stimulation protocol and / or adjustment to a stimulation protocol may be made utilizing this information. For example, a subject with an ultrasound that shows PCOS may have a dose adjustment made to one or more medications received and / or utilized during a stimulation protocol. In addition, the length of her stimulation protocol may be modified based on her PCOS diagnosis. In an embodiment, an ultrasound may be repeated one or more times throughout a subject’s stimulation protocol, and information obtained may be utilized to adjust her stimulation protocol in real time.

[0313] B. Oocyte stimulation protocols

[0314] A physician or skilled practitioner may determine the stimulation protocol of oocyte release directed to a subject using the described biological parameters. Such biological parameters include hormone levels (e.g., baseline hormone levels and / or hormone levels due to use of contraceptives), subject anatomy (e.g., follicle size, follicle count, ovarian morphology, and / or uterine morphology), among other biological parameters known to a skilled practitioner. A skilled practitioner may administer a stimulation protocol with any one or a combination of triggering agents, or compositions directed to stimulate follicular maturation and oocyte release, described herein.

[0315] Hormone levels or concentrations of other relevant compounds of the biological sample may include estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4), estrone (E1 ), estriol (E3), testosterone, androgens, dehydroepiandrosterone (DHEA), triiodothyronine (T3), tetraiodothyronine (T4), calcitonin, melatonin, insulin, cortisol, human growth hormone (HGH), adrenaline levels and the like. In some embodiments, the measurement of hormone levels may be based on blood analysis of the biological sample. For example, blood analysis may include plasma hormone analysis techniques. In some embodiments, measurement of hormone levels may be based on saliva hormone testing techniques. Measurement of hormone levels may be based on other forms of analysis such as hair, urine, and any other form of biological samples described throughout this disclosure. A subject may have a baseline serum level of estradiol from about 30 pg / mL to about 60 pg / mL (e.g., from about 30 pg / mL to about 45 pg / mL, from about 40 pg / mL to about 55 pg / mL, or from about 45 pg / mL to about 60 pg / mL; e.g., about 30 pg / mL, about 35 pg / mL, about 40 pg / mL, about 45 pg / mL, about 50 pg / mL, about 55 pg / mL, or about 60 pg / mL) prior to the follicular triggering period. A subject may have a baseline serum level of progesterone from about 0.5 ng / mL to about 2.5 ng / mL (e.g., from about 0.5 ng / mL to about 1 .0 ng / mL, from about 1 .0 ng / mL to about 1 .5 ng / mL, from about 1 .5 ng / mL to about 2.0 ng / mL, or from about 2.0 ng / mL to about 2.5 ng / mL; e.g., about 1 .0 ng / mL, about 1 .5 ng / mL, about 2.0 ng / mL, or about 2.5 ng / mL) prior to the follicular triggering period. Additionally, a subject’s contraception (e.g., hormonal contraception) usage may affect assignment of a stimulation protocol. Consideration for contraception may aid in determining the follicular triggering period in the woman’s menstrual cycle. For instance, and without limitation, a subject who is not using any form of contraception may begin her stimulation protocol with recombinant follicle stimulating hormone (rFSH) between the first and third day of her menstrual cycle, with preference for the second day of her menstrual cycle. In yet another non-limiting example, a subject who is using contraception may begin her stimulation protocol with rFSH 4-6 days (e.g., 4 days, 5 days, or 6 days) after consuming her last oral contraception pill, with preference for 5 days following the dosing of her last oral contraception pill. In an embodiment, rFSH stimulation may be utilized for 2 to 3 days (e.g., 2 days or 3 days), depending on a subject’s tolerance, follicle size, and / or growth dynamics. After this 2- or 3-day window, a coasting period of 1 to 3 days (e.g., 1 day, 2 days, or 3 days) may be utilized to monitor follicle size and allow for further follicle maturation and development. A “coasting period,” as used in this disclosure, is any period of time when a medication used throughout a stimulation protocol is not administered and / or consumed. A coasting period may last for example for 1 day, 2 days, 3 days, or more if medically necessary. During a coasting period, a subject may continue to receive one or more ultrasounds to monitor her progression.

[0316] Once a follicle size has reached anywhere from between about 8-10 mm (e.g., 7.5 mm, 8 mm, 8.5 mm, 9mm, 9.5 mm, 10 mm, 10.5 mm, or more), a subject may be triggered with a dose of a triggering agent, such as human chorionic gonadotropin (hCG). A “follicle measurement” as used in this disclosure, is any measurement of an ovarian follicle. A follicle may include any sac found in an ovary that contains an unfertilized egg. A follicle measurement may be obtained using any methodology as described herein, including for example an ultrasound, a manual measurement, an automated measurement and the like. In an embodiment, a double hCG injection may be utilized, to induce follicle maturation to prepare one or more follicles for retrieval. A double hCG injection may be two or three injections of hCG. A blood test for one or more hormone levels such as E2, P4, and LH may be performed on the trigger day of the double dose of hCG injection to monitor hormone levels. After the day of the double dose of hCG, one or more hormone levels may be measured such as for example with a blood test to determine and examine levels of E2, P4, and LH.

[0317] A “triggering agent” is a chemical that triggers cell generation in the ovaries. A triggering agent (e.g., a follicular triggering agent) may include any substance including any non-prescription and / or prescription product. A triggering agent (e.g., a follicular triggering agent) may include any one or combination of the non-limiting examples such as LUPRON DEPOT® (Abbott Laboratories, North Chicago, IL), Ganirelix (Ferring Pharmaceuticals, Saint-Prex, Switzerland), Cetrotide (Merck Global, Readington Township, NJ), GONAL-F® (Merck Global), FOLLISTIM® (Merck Global), BRAVELLE® (Ferring Pharmaceuticals), CLOMID® (Patheon Pharmaceuticals Inc., Waltham, MA), Serephene (Teva, Tel Aviv-Yafo, Israel), GLUCOPHAGE® (Merck Global), FORTAMET® (Mylan, Canonsburg, PA), PREGNYL® (Schering Plough, Kenilworth, NJ), NOVAREL® (Ferring Laboratories, Parsippany, NJ), Repronex (Ferring Pharmaceuticals), FACTREL® (Zoetis Canada Inc., Kirkland, Canada), MENOPUR® (Ferring Pharmaceuticals), and other drugs that induce cell generation in ovaries that one skilled in the art would understand as applicable. A triggering agent (e.g., a follicular triggering agent) may include human serum albumin, FSH, hCG, androstenedione, and doxycycline among other triggering agents known in the art. In one embodiment, a subject may not receive a triggering agent (e.g., a follicular triggering agent) to stimulate oocyte production. In one embodiment, a subject may receive multiple injections of a triggering agent over 1 to 4 days (e.g., 1 day, 2 days, 3 days, or 4 days) but no more than 5 days in the preferred stimulation protocol. A subject may receive multiple injections over multiple days such that a subject receives five dose injections of one or multiple triggering agents. For example, a subject may receive three days of stimulation using 300 IU to 700 IU of rFSH per injection (e.g., 300-500 I U, 400-600 IU, 500-700 IU, 300-350 IU, 350-400 IU, 400-450 IU, 450-500 IU, 500-550 IU, 550-600 IU, 600-650 IU, 650-700 IU; e.g., 300 IU, 325 IU, 350 IU, 375 IU, 400 IU, 425 IU, 450 IU, 475 IU, 500 IU, 525 IU, 550 IU, 575 IU, 600 IU, 625 IU, 650 IU, 675 IU, or 700 IU) with one or more injections per day. A subject may receive injections of hCG as a triggering agent (e.g., a follicular triggering agent) using 200-700 pg or 2,500-10,000 IU hCG (e.g., 200-500 pg, 300-600 pg, 400-700 pg, 200-300 pg, 300-400 pg, 400-500 pg, 500-600 pg, or 600-700 pg), with a preferred stimulation dose of 500 pg. A subject may receive one or more administrations (e.g., by oral administration or by injection) of clomiphene citrate in combination with other triggering agents with a dose of 50-150 mg (e.g., 50-75 mg, 60-80 mg, 75-100 mg, 90-115 mg, 110- 130 mg, 125-150 mg; e.g., 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg) of clomiphene citrate per injection for up to 8 days (e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or 8 days).

[0318] Prior to receiving a triggering agent, a subject’s serum may be evaluated for levels of hormones or other relevant compounds. A subject may have serum levels of estradiol from about 250 pg / mL to about 400 pg / mL (e.g., from about 250 pg / mL to about 275 pg / mL, from about 275 pg / mL to about 300 pg / mL, from about 300 pg / mL to about 325 pg / mL, from about 325 pg / mL to about 350 pg / mL, from about 350 pg / mL to about 375 pg / mL, or from about 375 pg / mL to about 400 pg / mL; e.g., about 250 pg / mL, about 260 pg / mL, about 270 pg / mL, about 280 pg / mL, about 290 pg / mL, about 300 pg / mL, about 310 pg / mL, about 320 pg / mL, about 330 pg / mL, about 340 pg / mL, about 350 pg / mL, about 360 pg / mL, about 370 pg / mL, about 380 pg / mL, about 390 pg / mL, or about 400 pg / mL) prior to receiving a triggering agent. A subject may have serum levels of progesterone from about 0.25 ng / mL to about 0.75 ng / mL (e.g., from about 0.25 ng / mL to about 0.35 ng / mL, from about 0.35 ng / mL to about 0.45 ng / mL, from about 0.45 ng / mL to about 0.55 ng / mL, from about 0.55 ng / mL to about 0.65 ng / mL, or from about 0.65 ng / mL to about 0.75 ng / mL; e.g., about 0.25 ng / mL, about 0.30 ng / mL, about 0.35 ng / mL, about 0.40 ng / mL, about 0.45 ng / mL, about 0.50 ng / mL, about 0.55 ng / mL, about 0.60 ng / mL, about 0.65 ng / mL, about 0.70 ng / mL, or about 0.75 ng / mL) prior to receiving a triggering agent. A subject may have serum levels of LH from about 1 .0 mIU / mL to about 2.5 mIU / mL (e.g., from about 1 .0 mIU / mL to about 1 .5 mIU / mL, from about 1 .5 mIU / mL to about 2.0 mIU / mL, or from about 2.0 mIU / mL to about 2.5 mIU / mL; e.g., about 1 .0 mIU / mL, about 1 .25 mIU / mL, about 1 .5 mIU / mL, about 1 .75 mIU / mL, about 2 mIU / mL, about 2.25 mIU / mL, or about 2.5 mIU / mL) prior to receiving a triggering agent. A subject may have serum levels of FSH from about 11 mIU / mL to about 14 mIU / mL (e.g., from about 11 mIU / mL to about 12 mIU / mL, from about 12 mIU / mL to about 13 mIU / mL, or from about 13 mIU / mL to about 14 mIU / mL; e.g., about 11 mIU / mL, about 12 mIU / mL, about 13 mIU / mL, or about 14 mIU / mL) prior to receiving a triggering agent.

[0319] The triggering agent (e.g., a follicular triggering agent) may be administered over a course of time to produce a follicle stimulation protocol that is a minimal stimulation protocol. The minimal stimulation protocol is configured by a skilled practitioner to trigger the release of a cell in the span of about 3 days. A “minimal stimulation protocol” is a stimulation process spanning over a shortened period of time, compared to average in vitro fertilization (IVF) stimulation protocols, to aid in inducing an ovary to produce an oocyte. Typically, the average span of time for a stimulation protocol using standard IVF is approximately 8-14 days. The minimal stimulation protocol may induce the release of a cell in a span of 8 days or less (e.g. 8 days or less, 7 days or less, 6 days or less, 5 days or less, 4 days or less, 3 days or less, 2 days or less, or 1 day; e.g., between 1 -3 days, between 2-4 days, between 3-5 days, between 4-6 days, between 5-7 days, or between 6-8 days; e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or 8 days), which is a shorted period of time compared to the 8-14 days of standard IVF stimulation protocols. The average time for performing a minimal stimulation protocol may be 2 days. The average time for performing a minimal stimulation protocol may be 3 days. The average time for performing a minimal stimulation protocol may be 4 days. The average time for performing a minimal stimulation protocol may be 5 days. The average time for performing a minimal stimulation protocol may be 6 days. In an embodiment, the minimal stimulation protocol may not require administration of a follicular triggering agent for successful retrieval and subsequent maturation of an oocyte. In an embodiment, the minimal stimulation protocol may include selecting a first triggering agent (e.g., a follicular triggering agent) and selecting a second triggering agent (e.g., a follicular triggering agent) as a function of a follicle measurement and / or other biological sample data.

[0320] C. Oocyte retrieval

[0321] Following follicular stimulation, oocytes (or a group of cells containing an oocyte) are retrieved from the subject. An “oocyte,” as used in this disclosure, is a reproductive cell originating from an ovary. Approximately 24-48 hours (e.g., between 24-32 hours, between 32-40 hours, between 40-48 hours; e.g., about 24 hours, about 28 hours, about 32 hours, about 36 hours, about 40 hours, about 44 hours, about 48 hours) after final dose of triggering agent (e.g., a follicular triggering agent) that is administered, a subject may undergo an oocyte retrieval. On the day of oocyte retrieval, a blood test for one or more hormone levels such as E2, LH, FSH and / or P4 may be performed to ensure quality metrics, hormone levels are within range, and / or that hCG dose was ingested. Hormone levels of E2 may be from about 300 pg / mL to about 450 pg / mL (e.g., from about 300 pg / mL to about 350 pg / mL, from about 350 pg / mL to about 400 pg / mL, or from about 400 pg / mL to about 450 pg / mL; e.g., about 300 pg / mL, about 325 pg / mL, about 350 pg / mL, about 375 pg / mL, about 400 pg / mL, about 425 pg / mL, or about 450 pg / mL) on the day of oocyte retrieval. Hormone levels of LH may be from about 3 mIU / mL to about 6 mIU / mL (e.g., from about 3 mIU / mL to about 4 mIU / mL, from about 4 mIU / mL to about 5 mIU / mL, or from about 5 mIU / mL to about 6 mIU / mL; e.g., about 3 mIU / mL, about 3.5 mIU / mL, about 4 mIU / mL, about 4.5 mIU / mL, about 5 mIU / mL, about 5.5 mIU / mL, or about 6 mIU / mL) on the day of oocyte retrieval. Hormone levels of FSH may be from about 6 mIU / mL to about 9 mIU / mL (e.g., from about 6 mIU / mL to about 7 mIU / mL, from about 7 mIU / mL to about 8 mIU / mL, or from about 8 mIU / mL to about 9 mIU / mL; e.g., about 6 mIU / mL, about 6.5 mIU / mL, about 7 mIU / mL, about 7.5 mIU / mL, about 8 mIU / mL, about 8.5 mIU / mL, or about 9 mIU / mL) on the day of oocyte retrieval. Hormone levels of P4 may be from about 0.5 ng / mL to about 1 .5 ng / mL (e.g., from about 0.5 ng / mL to about 1 .0 ng / mL, from about 0.75 ng / mL to about 1 .0 ng / mL, from about 1 .0 ng / mL to about 1 .5 ng / mL, or from about 1 .25 ng / mL to about 1 .5 ng / mL; e.g., about 0.5 ng / mL, about 0.75 ng / mL, about 1 .0 ng / mL, about 1 .25 ng / mL, or about 1 .5 ng / mL) on the day of oocyte retrieval.

[0322] Oocytes (or a group of cells containing an oocyte) are retrieved from the subject using methods known in the art. For example, oocytes may be retrieved via aspiration using a transvaginal ultrasound with a needle guide on the probe to suction released follicular contents. Follicular aspirates may then be examined using a dissection microscope and washed with HEPES media (G-MOPS Plus, VITROLIFE®) and filtered with a 70-micron cell strainer (FALCON®, Corning). Oocytes and / or COCs are then transferred to culture dishes and media to begin co-culturing and appropriate controls, as described herein. Other retrieval methods may include an extraction device, such as a needle, syringe, vial, lancet, Evacuated Collection Tubes (ECT), tourniquet, vacuum extraction tube systems, any combination thereof and the like. For example, the extraction device may comprise a butterfly needle set.

[0323] A retrieved oocyte may include but is not limited to an immature oocyte, a mature oocyte, a group of one or more oocytes, a group of one or more cells, such as a cumulus oocyte complex, among other examples. A “cumulus oocyte complex” (COC) as used in this disclosure, is an oocyte containing one or more surrounding cumulus cells. A COC may contain an immature oocyte. A COC may contain a mature oocyte.

[0324] An “immature oocyte” as used in this disclosure is one or more immature reproductive cells originating in the ovaries. In some embodiments, an immature oocyte may be an oocyte including but not limited to germinal vesicle stage (GV) and metaphase I stage (Ml) oocytes, as described further below. In some embodiments, an immature oocyte may be a plurality of oocytes. An immature oocyte may be immature cumulus-oocyte-complexes (COCs) taken from a subject. A “mature oocyte” as used in this disclosure, may be one or more mature oocytes in metaphase II stage (MH). Once retrieved, a COC may rest for 1 hour, 2 hours, 3 hours or more to allow for equilibration to in vitro conditions for in vitro maturation.

[0325] At the time of retrieval, any one or more of the retrieved oocytes or cells described herein may be appropriately frozen and stored using methods known in the art for future use, analysis, or experimentation. Additionally, any one or more of the retrieved oocytes or cells described herein may be used fresh (i.e., ready for immediate use such as use for in vitro maturation or any one or more analyses or experimentation described herein).

[0326] III. Method of oocyte rescue

[0327] A. Oocyte denudation

[0328] Following oocyte retrieval methods described above, one or more COCs may require oocyte denudation. As described in this disclosure, “oocyte denudation” refers to the removal of cumulus cells or other cell types from the oocyte by means of mechanical separation, chemical separation, or combinations thereof. Several methods of oocyte denudation are known in the art. In some embodiments, denudation may occur in a IVM well, by gently mechanically disassociating cells by pipetting to remove most cumulus and / or granulosa cells. If enzymatic disassociation is needed, the cells may be transferred to a separate dish for hyaluronidase treatment. COCs may be stripped with stripper tips and washed in IVM media or MOPS plus media to clean the oocyte for imaging and if needed inactivate hyaluronidase. Stripper tips may include 200 micron and / or 400 microns for fine cleaning. In some embodiments, germinal vesical (GV)-stage) and metaphase I (Ml)-stage oocytes may be formulated and utilized in cultivation following denudation of the COCs. Denuded COCs may be transferred to a separate culture dish for imaging. B. Co-cultu ing oocytes for in vitro maturation

[0329] / . Co-culture contents and timing

[0330] In the methods described herein, an oocyte may be combined with one or more OSCs such as one or more granulosa or stroma cells. An OSC is a cumulus cell that surrounds the oocyte to ensure healthy oocyte and subsequent embryo development. In some embodiments, the granulosa and / or stroma co-culture cells derive from differentiated induced pluripotent stem cells (iPSCs) such as human iPSCs (hiPSCs) as described herein (see, Section 1(A)). As used in this disclosure, a “co-culture” is a cell cultivation set-up, in which two or more different populations of cells are grown with some degree of contact between them. In some embodiments, steroidogenic granulosa cells derived from human induced pluripotent stem cells hiPSCs, may be co-cultured with immature oocytes to form COCs, thereby reconstituting the follicular niche in vitro to promote rapid and efficient oocyte maturation in a manner that reinforces oocyte health and developmental competence. As used in this disclosure, a “steroidogenic granulosa cell” is a granulosa cell expressing high levels of steroidogenic enzymes that produce estradiol. For example, a steroidogenic granulosa cell may be a mural granulosa cell extracted from the antral follicle. Applying steroidogenic granulosa cells in the co-cultures of COCs may increase oocyte maturation in vitro after egg / oocyte retrieval, allowing for utilization of all retrieved eggs / oocyte by directly supplying nutrients, raw materials, and mechanical support to oocytes throughout gametogenesis and folliculogenesis. Steroidogenic granulosa cells may grow and perform oocyte maturation of immature oocytes in standard IVF and IVM media as described further below. This may increase the overall pool of available, healthy oocytes for use in IVF and reduce the number of ova / oocyte retrieval procedures a user is subjected to.

[0331] In some embodiments of the method, a cell culture may be formed by combining an immature oocyte with a population of engineered OSCs, which is added to mature the oocyte in the cell culture and thus create a COC after extraction of one or more oocytes following the minimal stimulation protocol. In an embodiment, one or more specialized granulosa cells and / or specialized stroma cells may be thawed during a resting period of one or more COCs. In an embodiment, anywhere from between 50,000- 150,000 specialized granulosa cells (e.g., 50,000-60,000 cells, 60,000-70,000 cells, 70,000-80,000 cells, 80,000-90,000 cells, 90,000-100,000 cells, 100,000-110,000 cells, 110,000-120,000 cells, 120,000- 130,000 cells, 130,000-140,000 cells, or 140,000-150,000 cells; e.g., 50,000 cells, 55,000 cells, 60,000 cells, 65,000 cells, 70,000 cells, 75,000 cells, 80,000 cells, 85,000 cells, 90,000 cells, 95,000 cells, 100,000 cells, 105,000 cells, 110,000 cells, 115,000 cells, 120,000 cells, 125,000 cells, 130,000 cells, 135,000 cells, 140,000 cells, 145,000 cells, or 150,000 cells) may be combined with a COC during culturing. In an embodiment, thawed specialized granulosa cells may be placed into a culture media prior to COC retrieval, including anywhere from about 24-120 hours beforehand (e.g., about 24-48 hours, about 48-72 hours, about 72-96 hours, about 96-120 hours; e.g., about 24-36 hours, about 30-40 hours, about 36-48 hours, about 48-56 hours, about 56-72 hours, about 72-84 hours, about 80-96 hours, about 90-100 hours about 96-108 hours, about 108-120 hours; e.g., about 24 hours, about 30 hours, about 36 hours, about 42 hours, about 48 hours, about 56 hours, about 60 hours, about 65 hours, about 72 hours, about 78 hours, about 86 hours, about 92 hours, about 96 hours, about 102 hours, about 110 hours, about 115 hours, about 120 hours). A COC may be transferred into culture media containing thawed specialized granulosa cells to form a group culture as described below in more detail. In an embodiment, a group culture may be cultured in an incubator ranging in time from anywhere between 12-48 hours (e.g., 12-16 hours, 12-20 hours, 18-24 hours, 18-36 hours, 24-36 hours, 36-48 hours; e.g., 12 hours, 16 hours, 20 hours, 24 hours, 28 hours, 32 hours, 36 hours, 40 hours, 44 hours, 48 hours). The co-culture may be conducted at a biologically suitable temperature, e.g., 37°C.

[0332] In some embodiments of the method, a retrieved oocyte, including immature cumulus-oocyte complexes, may be cultured in a group culture. A “group culture” is an extracted COC combined with one or more additional cells. An additional cell may include any cell grown together with an extracted COC. An additional cell may include a specialized stroma cell. An additional cell may include a specialized granulosa cell. In an embodiment, a group culture may be cultured and / or incubated for a particular length of time, such as from between 12-120 hours (e.g., 12-24 hours, 12-36 hours, 24-48 hours, 36-60 hours, 54-72 hours, 68-96 hours, 96-120 hours; e.g., 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours, 36 hours, 38 hours, 40 hours, 42 hours, 44 hours, 46 hours, 48 hours, 50 hours, 52 hours, 54 hours, 56 hours, 58 hours, 60 hours, 62 hours, 64 hours, 66 hours, 68 hours, 70 hours, 72 hours, 74 hours, 76 hours, 78 hours, 80 hours, 82 hours, 84 hours, 86 hours, 88 hours, 90 hours, 92 hours, 94 hours, 96 hours, 98 hours, 100 hours, 102 hours, 104 hours, 106 hours, 108 hours, 110 hours, 112 hours, 114 hours, 116 hours, 118 hours, or 120 hours). For example, group culturing may include culturing the COCs with a granulosa co-culture as described further below. In some embodiments, group culturing may include culturing a control group of COCs with no co-culture, as described further below. In some embodiments, a user may donate immature oocytes, such as GV-stage and Ml-stage oocytes that may be used in medium as part of the group culture to help grow COCs. Oocyte donation may follow an oocyte retrieval process as discussed above. A subject participating in oocyte donation may be different, or the same, from the subject related to the second biological sample containing immature COCs. In some embodiments, an oocyte donation subject may undergo a stimulation protocol as disclosed above.

[0333] In some embodiments, the maturity of the oocyte retrieved from the subject may dictate the length of time during which the oocyte is co-cultured with ovarian support cells (e.g., specialized granulosa cells and / or specialized stroma cells). For example, less mature oocytes (e.g., GV oocytes) may require longer co-culturing periods than oocytes at a more advanced stage of meiosis (e.g., Ml oocytes).

[0334] In some embodiments regarding the culture of oocytes, cell culture media may include LAG media (Medicult, COOPERSURGICAL®). For example, LAG media may be used for the incubation of oocytes and / or COCs post-retrieval from minimal stimulation protocol. For example, a modified-Medicult IVM media may be used as a baseline control during the culturing process. In some embodiments, the cell culture media may include metabolites or additives, including human serum albumin, FSH, hCG, androstenedione, doxycycline, or any combination thereof. In some embodiments, the cell culture media is a LAG media or a Medicult IVM media, to which is added human serum albumin, FSH, hCG, androstenedione, and / or doxycycline. In some embodiments, the cell culture media is a LAG media or a Medicult IVM media, to which is added human serum albumin, FSH, hCG, Media may be equilibrated for about 18 to 24 hours (e.g., about 18 hours, about 20 hours, about 22 hours, about 24 hours) pre-culture in a standard sterile 37°C incubator with O2 (e.g., having a 1 -10% O2 atmosphere, such as 4-8% 02 or 5- 7% O2, e.g., 6% O2) and proper CO2 levels, which are known in the art. Co-cultures and specialized granulosa cell cultures may be adherent cell cultures in cell culture dishes or flasks. Co-cultures and specialized granulosa cell cultures may be suspension cell cultures in cell culture flasks. Cell culture materials and methods include standard sterile cell culturing methods known in the art. Cell morphology and cell viability may be evaluated via one or more established methods known in the art.

[0335] A population of OSCs may be prepared for a co-culture (e.g., a co-culture with an oocyte (e.g., an immature oocyte)) from an intermediate or master cell bank and may be stored for later use. For example, a population of ovarian support cells (e.g., ovarian granulosa cells) may be cryopreserved and then thawed and equilibrated in a cell culture media prior to co-culture. In some embodiments, the ovarian support cells are centrifuged to form a cell pellet and are subsequently resuspended in media suitable for in vitro maturation. In some embodiments, the ovarian support cells are centrifuged one or more additional times and, each time, are resuspended in in vitro maturation media. The ovarian support cells may then be co-cultured with an oocyte obtained from the subject undergoing an ART procedure, thereby inducing oocyte maturation.

[0336] / ' / . Granulosa cells from hiPSCs

[0337] Specialized granulosa cells utilized in the methods described herein may be created from hiPSCs using transcription factor (TF)-directed protocols described herein.

[0338] In some embodiments, a subject may donate hiPSCs. hiPSCs donation may follow an oocyte retrieval process as discussed above. A subject participating in hiPSCs donation may be different, or the same, from the subject from which the oocyte was retrieved. In some embodiments, a hiPSC donor may undergo a stimulation protocol as disclosed above.

[0339] In some embodiments, hiPSCs, granulosa cells, cumulus cells, oocytes, GV-stage oocytes, Ml- stage oocytes, Mil-stage oocytes and all other types of cells described through this disclosure may be lysed, extracted for genomic material and flash frozen for further manipulation and / or analysis (e.g., for analysis as part of an omics data collection technique described in Section I ll(C)(iii), below). For example, cells may undergo enzymatic cell lysis using enzymes such as lysozyme, lysostaphin, zymolase, cellulose, protease or glycanase, and the like. Other lysis methods may be applied such as chemical lysis, detergent lysis, alkaline lysis, mechanical lysis, thermal lysis, acoustic lysis, physical lysis, nonmechanical lysis and other lysis methods known in the art. In some embodiments, culture media may be flash frozen. Freezing methods may include using a cryoprotective agent such as dimethyl sulfoxide and / or any other freezing method known in the art.

[0340] C. Oocyte rescue

[0341] / . Oocyte scoring

[0342] At any stage of in vitro maturation or directly following in vitro maturation, an oocyte and / or granulosa cells may be appropriately frozen and stored for future analyses, experimentation, or for use in oocyte maturation. Oocytes may be scored with a scoring metric based on their morphology as determined by imagine analysis. In some embodiments, assignment of the scoring metric may include imaging the group cultures and analyzing the images of one or both of co-culture and no co-culture growth media-only control groups. In some embodiments, oocytes are scored and comparatively analyzed during any such stage of in vitro maturation. For example, group culture images may contain a pre-culture group COC image, a post-culture group COC image, and a post-culture denuded oocyte image. In some embodiments, oocytes subjected to scoring have never been frozen. In some embodiments oocytes subjected to scoring via image analysis may be thawed after storage by freezing. In some embodiments, oocytes subjected to scoring may be retrieved without in vitro maturation as described. In some embodiments, oocytes subjected to scoring may be cultured without described granulosa. In some embodiments, images may be sent to a qualified third party, such as an embryologist, developmental biologist, or other relevant skilled practitioner for scoring assignment.

[0343] In some embodiments of the methods described herein, oocytes may be assessed and subsequently classified by their maturation state according to the following criteria:

[0344] GV - presence of a germinal vesicle, typically containing a single nucleolus within the oocyte. Ml - absence of a germinal vesicle within the oocyte and absence of a polar body in the perivitelline space between the oocyte and the zona pellucida.

[0345] Mil - absence of a germinal vesicle within the oocyte and presence of a polar body in the perivitelline space between the oocyte and the zona pellucida.

[0346] In some embodiments of the method, the scoring metric may include total oocyte scoring (TOS) as a function of analyzing the imaged group cultures via relevant microscopy or imaging analysis software. Methods and approaches of TOS have been described in the art (Lazzaroni-Tealdi et al., PLoS One 10:e0143632, 2015). Oocyte scoring may include metrics such as shape, size, ooplasm characteristics, structure of the perivitelline space (PVS), zona pellucida (ZP), polar body (PB) morphology, among other possible qualifiers. Total oocyte scoring on both pre and post culture oocyte images for generation of the TOS metric may be based on a scale system of -6 to + 6.

[0347] Regarding oocyte shape, if oocyte morphology is poor (dark general oocyte coloration and / or ovoid shape), it may be assigned a value of -1 ; if it is almost normal (less dark general oocyte coloration and less ovoid shape), it may be assigned a value of 0; if it is judged to be normal, it may be assigned a value of + 1 . Regarding oocyte size: if oocyte size is defined as abnormally small or large, it may be assigned a value -1 if size is below 120 pm or greater 160 pm. If the size is almost normal, i.e., does not deviate from normal by more than 10 pm, a value of 0 may be assigned, and a value of + 1 may be assigned if oocyte size is within normal range > 130 pm and <150 pm. Regarding ooplasm characteristics, if the ooplasm is very granular and / or very vacuolated and / or demonstrates several inclusions, a value of -1 may assigned. If it is only slightly granular and / or demonstrates only few inclusions, a value of 0 may be assigned. Absence of granularity and inclusions may result in a +1 value. Regarding structure of the perivitelline space (PVS), the PVS may defined as -1 with an abnormally large PVS, an absent PVS or a very granular PVS. It may be assigned a value of 0 with a moderately enlarged PVS and / or small PVS and / or a less granular PVS. A value of +1 may be assigned to a normal size PVS with no granules. Regarding, zona pellucida (ZP), if ZPs is very thin or thick (<10 pm or >20 pm) the oocyte may be assigned a -1 . If the ZP does not deviate from normal by more than 2 pm it may be assigned 0. A normal zona (> 12 pm and <18 pm) may be assigned a +1 . Regarding polar body (PB) morphology, PB morphology is defined as follows: Flat and / or multiple PBs or zero PBs, granular and / or either abnormally small or large PBs is designated as -1 . PBs, judged as fair but not excellent may be designated as 0, and a designation of +1 may be given to PBs of normal size and shape. In some embodiments, Mil oocytes PB score may not be aggregated into TOS.

[0348] In some embodiments of the method, the scoring metric may include performing an outcome analysis as a function of the TOS. Parametric or non-parametric tests may be applied to determine the significance of findings during the analysis. Outcome analysis may be used to determine GV-stage to Milstage oocyte maturation rate; GV-stage to Ml-stage oocyte maturation rate; Ml-stage to Mil-stage oocyte maturation rate; Average Total Oocyte Score; Average Oocyte Shape; Average Oocyte Size; Average Ooplasm quality; Average PVS quality; Average ZP quality; Average Polar Body quality, and the like. In some embodiments these outcomes may be reported as a mean or median and a deviation.

[0349] / ' / . In vitro fertilization and embryo culture

[0350] In some embodiments of the methods, any one or more ova or oocytes as described herein may be evaluated for quality or maturation state, such as by the scoring metrics described herein, to determine their readiness for use in in vitro fertilization and embryo formation.

[0351] In some embodiments of the method, the ova or oocytes may be matured via in vitro maturation and subsequently utilized for IVF and / or ART as described herein. Any one or more oocytes may be utilized for intracytoplasmic sperm injection (ICSI). Following fertilization of the ovum by contact with one or more sperm cells, the subsequently formed zygote can be matured ex vivo so as to produce an embryo, such as a morula or blastula (e.g., a mammalian blastocyst), which can then be transferred to the uterus of a subject (e.g., a subject from which the oocyte was initially harvested) for implantation into the endometrium. Embryo transfers that can be performed using the methods described herein include fresh embryo transfers, in which the ovum or oocyte used for embryo generation is retrieved from the subject and the ensuing embryo is transferred to the subject during the same menstrual cycle. The embryo can alternatively be produced and cryopreserved for long-term storage prior to transfer to the subject.

[0352] A method of IVM wherein an oocyte (e.g., a GV or Ml stage oocyte) is co-cultured with a population of OSCs (e.g., a population of OSCs produced by a method described herein) can have improved outcomes for subjects that are seeking an ART procedure or are undergoing an ART procedure (e.g., IVF). In some embodiments, a method of IVM wherein an oocyte (e.g., a GV or Ml stage oocyte) is co-cultured with a population of OSCs (e.g., a population of OSCs produced by a method described herein) has improved outcomes as determined by one or more of improved oocyte maturation rates (e.g., as measured by the proportion of Mil stage oocytes following culturing) fertilization rates, blastocyst formation rates, high quality blastocyst formation rates, euploid blastocyst formation rates, successful implantation, maintained pregnancy, and live birth of offspring (e.g., offspring with no developmental abnormalities). In some embodiments, one or more improved outcomes such as maturation rate, fertilization rate, blastocyst formation rate, high quality blastocyst formation rate, and euploid blastocyst formation rate may be evaluated ex vivo with an oocyte (e.g., a human or a murine oocyte). In some embodiments, one or more improved outcomes are based on a proportion of retrieved oocytes (e.g., oocytes retrieved from a subject undergoing ovarian stimulation). As an example, maturation rate may be determined based on the proportion of retrieved GV or Ml stage oocytes that matured (i.e., reached Mil stage) following the method of IVM.

[0353] In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) is more likely to result in oocyte maturation (e.g., formation of an Mil stage oocyte), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a higher oocyte maturation rate following culturing, as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a maturation rate following culturing that is about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher.

[0354] In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) is more likely to result in fertilization following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a higher fertilization rate following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a fertilization rate following contact with a mature sperm cell (e.g., via ICSI) that is about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher.

[0355] In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) is more likely to result in a blastocyst following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) has a higher blastocyst formation rate following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a blastocyst formation rate following contact with a mature sperm cell (e.g., via ICSI) that is about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a higher likelihood of obtaining a blastocyst such that a subject undergoing ovarian stimulation (e.g., minimal ovarian stimulation method) undergoes fewer cycles of ovarian stimulation and oocyte retrieval as compared to a method of IVM in which an oocyte is cultured in a cell culture media with an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a likelihood of resulting in blastocyst formation following contact with a mature sperm cell for each oocyte retrieval cycle (e.g., following ovarian stimulation) that is about 90% or higher (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% or higher).

[0356] In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) is more likely to result in a high quality blastocyst following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. A high quality blastocyst is one that has a trophoblast (i.e., an outer layer of cells that derives from the trophectoderm), an inner cell mass that includes a fluid-filled cavity, and a development stage that is indicative of a high quality blastocyst as measured, e.g., by the Gardner blastocyst grading system. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) has a greater high quality blastocyst formation rate following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a high quality blastocyst formation rate following contact with a mature sperm cell (e.g., via ICSI) that is about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a higher likelihood of obtaining a high quality blastocyst such that a subject undergoing ovarian stimulation (e.g., minimal ovarian stimulation method) undergoes fewer cycles of ovarian stimulation and oocyte retrieval as compared to a method of IVM in which an oocyte is cultured in a cell culture media with an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a likelihood of resulting in high quality blastocyst formation following contact with a mature sperm cell for each oocyte retrieval cycle (e.g., following ovarian stimulation) that is about 80% or higher (e.g., 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% or higher).

[0357] In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) is more likely to result in a euploid blastocyst following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. A euploid blastocyst is a blastocyst that has the expected number of chromosomes for a species (i.e., 46 chromosomes for a human blastocyst or 40 chromosomes for a mouse) and may be evaluated by genetic test for aneuploidy (e.g., a preimplantation genetic test for aneuploidy (PGT-A)). In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) has a higher euploid blastocyst formation rate following contact with a mature sperm cell (e.g., via ICSI), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a euploid blastocyst formation rate following contact with a mature sperm cell (e.g., via ICSI) that is about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher). In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a higher likelihood of obtaining a euploid blastocyst such that a subject undergoing ovarian stimulation (e.g., minimal ovarian stimulation method) requires fewer cycles of ovarian stimulation and oocyte retrieval as compared to a method of IVM in which an oocyte is cultured in a cell culture media with an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a likelihood of resulting in euploid blastocyst formation following contact with a mature sperm cell for each oocyte retrieval cycle (e.g., following ovarian stimulation) that is about 80% or higher (e.g., 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% or higher).

[0358] In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) is more likely to result in successful embryo implantation (i.e., into a uterus) and maintained pregnancy after obtaining a blastocyst (e.g., a high quality and / or euploid blastocyst), as compared to a traditional IVM method in the art, such as culturing an oocyte in a cell culture media without an OSC. In some embodiments, the method of IVM yields a higher likelihood of embryo implantation such that a subject undergoing ovarian stimulation (e.g., minimal ovarian stimulation) requires fewer cycles of ovarian stimulation and oocyte retrieval as compared to a method of IVM in which an oocyte is cultured in a cell culture media with an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a likelihood of resulting in successful embryo implantation for each oocyte retrieval cycle (e.g., following ovarian stimulation) that is about 50% or higher (e.g., about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher).

[0359] In some embodiments, the method of IVM yields a higher likelihood of pregnancy such that a subject undergoing ovarian stimulation (e.g., minimal ovarian stimulation) requires fewer cycles of ovarian stimulation and oocyte retrieval as compared to a method of IVM in which an oocyte is cultured in a cell culture media with an OSC. In some embodiments, a method of IVM that includes co-culturing an oocyte (e.g., a GV or Ml stage oocyte) with a population of OSCs (e.g., OSCs produced by a method described herein) has a likelihood of resulting in pregnancy implantation for each oocyte retrieval cycle (e.g., following ovarian stimulation) that is about 30% or higher (e.g., about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher). In some embodiments, the subject maintains pregnancy following implantation of an embryo or blastocyst (e.g., following IVM of an oocyte by co-culturing the oocyte with a population of a population of OSCs produced by a method described herein) for at least 28 weeks, at least 30 weeks, at least 35 weeks, or at least 38 weeks. In some embodiments, the subject maintains pregnancy following implantation of an embryo or blastocyst (e.g., following IVM of an oocyte by co-culturing the oocyte with a population of a population of OSCs produced by a method described herein) for 28 weeks to 38 weeks (e.g., 28 weeks, 29 weeks, 30 weeks, 31 weeks, 32 weeks, 33 weeks, 34 weeks, 35 weeks, 36 weeks, 37 weeks, 38 weeks, 39 weeks, 40 weeks, 41 weeks, 42 weeks, or 43 weeks). In some embodiments, the pregnancy following implantation of an embryo or blastocyst (e.g., following IVM of an oocyte by co- culturing the oocyte with a population of a population of OSCs produced by a method described herein) results in a live birth and delivery of an infant. In some embodiments, the infant has no developmental abnormalities and / or has an Apgar score of 7 or higher.

[0360] Hi. Omic data collection and analyses of oocytes, cells, and culture media

[0361] In some embodiments of the method, the scoring metric may include an Omics-based analysis. For example, frozen cell lysates and cell culture media may be analyzed for bulk RNA-sequencing, whole genome bisulfite sequencing (WGBS), mass spectrometry-based proteomics and metabolomics. Cell culture media may be utilized for metabolomics analysis to determine changes in molecular content of media following co-culture compared to pre-culture media controls. This may be utilized to profile dynamic changes in paracrine signaling between granulosa cells and oocytes. The data gathered may then be aggregated for downstream analysis for determination of changes in epigenetic state, metabolite presence, and gene expression between different co-culture conditions and controls.

[0362] In some embodiments of the method, an omics-based analysis may include, genomics, proteomics, transcriptomics, pharmacogenomics, epigenomics, microbiomics, lipidomics, glycomics, transcriptomics culturomics, and / or any other omics one skilled in the art would understand as applicable. In some embodiments, after cultivation, an oocyte that has failed to mature, showing GV or Ml characteristics, may be harvested for single cell RNA-sequencing, along with their associated granulosa cells from their culture. For this, oocytes and granulosa cells may be flash frozen and for library preparation. Of the oocytes that display Mil oocyte development, half may be harvested for single cell RNA-sequencing along with their associated granulosa cells using the above flash freeze methods described throughout this disclosure. The remaining half of Mil oocytes may be utilized for proteomic studies. The culture media for all conditions may additionally be flash frozen and utilized for metabolomics and proteomics to identify cholesterol metabolite levels and paracrine protein production. For example, frozen cell lysates and cell culture mediums may be analyzed for bulk RNA-sequencing, whole genome bisulfite sequencing (WGBS), mass spectrometry-based proteomics and metabolomics. Cell culture media may be utilized for metabolomics analysis to determine changes in molecular content of media following co-culture compared to pre-culture media controls to profile dynamic changes in paracrine signaling between granulosa cells and oocytes. As the media components are flash frozen, the sample is effectively quenched and amenable to metabolic assessment. The data gathered may then be aggregated for downstream analysis for determination of changes in epigenetic state, metabolite presence, and gene expression between different co-culture conditions and controls.

[0363] IV. Kits or articles of manufacture

[0364] The compositions or methods described herein can be provided in a kit for use in reprogramming iPSCs (e.g., hiPSCs) into a population of OSCs (e.g., granulosa cells and / or stroma cells). In some embodiments, the compositions and methods described herein can be provided in a kit for use in coculturing one or more oocytes with OSCs to produce one or more mature oocytes, optionally wherein the resulting mature oocytes are further fertilized to form an embryo in an ART or IVF procedure. In some embodiments, the kit may include a package insert that instructs a user of the kit to perform iPSC differentiation and / or in vitro maturation. In further embodiments, the kit may include a package insert that instructs a user of the kit to perform any one of the methods of ovarian stimulation and / or oocyte retrieval described herein. The kit may optionally include a syringe or device for administering the compositions of the present disclosure or for retrieving one or more oocytes. In some embodiments, the kit may include one or more additional cell media or agents used for cell culture. In some embodiments, the kit includes one or more antibodies or binding molecules to detect the expression of one or more genes or biomarkers described herein. EXAMPLES

[0365] Example 1. A method of producing ovarian support cells by reprogramming induced pluripotent stem cells

[0366] Induced pluripotent stem cells (iPSCs) are derived from adult cells that have been reprogrammed into stem cells with the potential to differentiate into any cell type in the body and, as a result, have widespread applications in biomedicine. We have applied an established combinatorial and technical platform to engineer iPSCs with inducible transcription factors that drive differentiation towards ovarian cell types. These cells, which are called ovarian support cells (OSCs), express protein markers similar to granulosa cells, the essential functional cells of the ovary, and exhibit similar transcriptomic and steroidogenic profiles. Our OSCs provide a much more physiologically relevant, ovarian-like dynamic environment for IVM than media alone, leading to improved maturation outcomes and therefore creating significant potential for our engineered cells as an ART to improve fertility treatments in the clinic. Detailed in this example is our work to develop and optimize approaches for consistent manufacturing at scale under good manufacturing practice conditions with animal origin-free materials without impacting product purity, efficacy, and safety. We provide a case study and methodology for clinical translation of both iPSCs in cell therapy and ART for fertility treatments, showing that a strategic plan for scalable and controlled manufacturing ultimately creates a much more consistent and functional product.

[0367] / . Methods for Example 1

[0368] Source material

[0369] We first procured an allogeneic hiPSC line (VCT-37-F35) from Reprocell USA (9000 Virginia Manor Rd #207, Beltsville, MD 20705) to serve as the starting material for our clinical-grade cell line. The stem-cell line, derived from human-skin fibroblasts, was generated under good manufacturing practice (GMP) conditions using a non-integrating, mRNA-based reprogramming technology with controlled conditions and GMP-compliant reagents used for the entirety of the manufacturing process. Regarding specific stages in that process, proper controls were implemented for fibroblast derivation according to established guidelines, while reprogramming and cell expansion took place under fully GMP conditions in compliance with regulatory standards and guidelines of the FDA, EMA, and PMDA. We performed a riskbased assessment for safety and suitability of the VCT-37-F35 parental cell line based on supporting documentation to evaluate compliance with regulatory requirements, finding donor eligibility compliant with 21 CFR 1271 , Subpart C and donor consent for broad use and indication. The sourced clonal hiPSC line was expanded in a Research Cell Bank (RCB) prior to our internal cell engineering. The Research Cell Bank was created by expanding the parental cell line for one passage and storing multiple samples cryopreserved to ensure sufficient material for engineering, as well as to secure a stock of the parental cell line in ideal culture conditions, either as a back-up or for future use. Reprocell, Inc., the provider of the original hiPSC line, executed in depth characterization to ensure conformance with established commercial release criteria, while we performed further testing in downstream steps of the process to confirm pluripotency, identity, genetic stability, and potency of cells.

[0370] Plasmid Manufacturing

[0371] Plasmids utilized for engineering were screened for identity, integrity, and purity verified by whole plasmid sequencing utilizing nanopore technologies and were stored at -20°C, while glycerol stocks of transformed bacteria are stored at -80°C. Plasmids encoding the transcription factors and piggyBac transpose were transfected into hiPSCs with a Lonza NUCLEOFECTOR™ device.

[0372] Cell Engineering

[0373] Engineering of hiPSCs with specific transcription factors was performed using a piggyBac transposase strategy, which enables integration of multiple copies of the transgene into the host genome. To increase efficiency of the engineering process, puromycin selection was utilized to eliminate cells without integration of the transcription factors. The engineered stem cells are exposed to the Rho- associated protein kinase inhibitor, Y-27632, and the WNT activator, the glycogen synthease kinase-3 inhibitor CHIR99021 , that together prime the cells into a mesodermal fate. Exposure to doxycycline throughout the entire process induces overexpression of the transcription factors, NR5A1 , RUNX2, and GATA4, directing differentiation of hiPSCs towards OSCs. This robust Dox-induced, TF-directed differentiation requires five days in culture.

[0374] Cell screening, selection, and preliminary characterization

[0375] Following the preliminary round of testing on the pooled population of transfected hiPSCs, clones were established by limiting dilution in multiwell plate format. All wells were closely monitored daily until identification of single clones in each well. Wells with more than one clone identified were discarded. Each identified clone was further expanded and cryopreserved resulting in 43 seed clones. Each clone was initially assigned a unique code based on their plate location. The 43 seed clones were subjected to genotyping PCR to identify the presence of the three transcription factors. This initial screening resulted in identification of nine clones harboring all the transcription factors, each of which were then subjected to a more in-depth screening process, including identity, potency, and safety assays for the identification of a lead candidate cell line. To identify the lead candidate, each of the nine clones was individually differentiated and subjected to a series of assays to ensure identity (pluripotency markers, donor identity, and genotyping), conformance (cell count and viability), potency (OSC production and function), and most importantly safety (genomic integrity, vector copy number, mycoplasma, sterility, and adventitious agents) of the clones. The leading candidate clone (2-D10) selected to be used as the starting material for the clinical-grade cell line was named CG-hiPSC.

[0376] Cell count and viability

[0377] Cell counts and viability assessments were performed using EVE™ Automated Cell Counter (NanoEnTeck, Seoul, South Korea) and NUCLEOCOUNTER® NC-202™ (ChemoMetec, Allerod, Denmark). hiPSC maintenance and OSC differentiation

[0378] The engineered stem cells were exposed to Rho kinase inhibitor, Y-27632, and the WNT activator, CHIR99021 , that prime the cells into a mesodermal fate. Cells were exposed to doxycycline for five days for induction of overexpression of transcription factors NR5A1 , RUNX2, and GATA4 to direct differentiation of hiPSCs to OSCs. Images of cells were taken with ECHO Revolve Microscope (Discover ECHO). Kayrotype analyses were performed by KARYOSTAT™ (ThermoFisher, Waltham, MA) and G- banding (WiCell Research Institute, Madison, Wl). Celli D was performed by ThermoFisher. Single cell RNA sequencing (scRNA-seq)

[0379] Files were generated following a split-set analysis workflow. First, bcl2fast1 was used to generate fastq files. A reference genome was generated using split-pipe and the Homo sapiens GRCh38 file, while using STAR and Samtools. Split-pipe was run for file processing and alignments against the reference genome. The files were generated in a nmtx matrix format. Following file combination, an Anndata object was made in h5 file format.

[0380] Files were analyzed by filtering out cells with less than 200 genes, and genes found in less than 3 cells were also filtered out. Cell counts were normalized to 10,000 unique molecular identifiers (UMIs) per sample and log (In) plus 1 transformed. Principal component analysis (PCA) was performed using the Scanpy package (v1 .9.6) based on 30 PCA components, and using PCA results, nearest neighbor analysis was performed. Batch correction was performed using Scanpy’s ComBat method. The number of components used for batch correction was 30, and the data was then transformed using Uniform Manifold Approximation and Projection (UMAP) method. Clusters were formed using the Leiden method with a resolution of 0.24, as well as for all the subsetted objects. Fifteen Leiden clusters were initially found, but following combination of clusters based on biological similarities resulted in nine clusters: Early GC I, Early GC II, Early GC III, GC I, GC II, GC III, Atresia / luteolysis, mitochondrial gene enriched (Atresia / luteolysis), and ribosomal gene enriched (Atresia / luteolysis).

[0381] The top 50 genes per cluster, as well as certain granulosa cell markers (GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, ITGB1 ), were analyzed in order to identify cluster cell types. Dot plots were also generated for analysis to see the expression levels of certain genes per cluster or per sample. Based on downstream analysis, cluster 0 and 5 were subset from the original object and they were re-clustered using the Leiden method at a higher resolution of 0.3. Further marker analysis was performed on these clusters to identify specific subgroups. Once all the subgroups were identified, the subset cluster groups of cluster 0 and cluster 5 were merged together with the original object. Gene signatures based on genes in the folliculogenesis stage were also analyzed and used for predicting cluster identification.

[0382] Based on the final object, four more subsets were generated: (1 ) a research use only (RUO)- OSC-Matrigel (RUO-OSC-M) object consisting of the following lots: lot 6, lot 7, lot 8, lot 29, lot 48, and lot 56; (2) an RUO-OSC-Vitronectin (RUO-OSC-V) object consisting of the following lots: lot 41 , lot 49, and lot 57; (3) an RUO-OSC-Laminin-521 (RUO-OSC-L) object consisting of lot 77 and lot 86; and (4) a CG- OSC-L object consisting of lot 88 and lot 90.

[0383] Some samples were excluded from the RUO-OSC-V subset due to a low scale. These samples include: RUO-OSC-V lot 37, RUO-OSC-V lot 39 and CG-OSC-V lot 0. UMAPS of all the subsets were generated with the cluster naming from the original object. Dot plots of markers from groups like: “GC Consistent,” “GC Unique,” “Steroid,” and “Pre GC" genes were also made to analyze gene expression in the newly subsetted groups for comparison among one another. Stacked bar plots indicating the percentage of each cell type in each sample were also generated in order to validate consistency and similarity amongst the samples. For each of the subsets, signature scores involving UMAPS and dot plots were generated for all clusters associated with the following groups: Ligand receptor genes, and growth factors. Additionally, dot plots were generated from those groups, reflecting per sample and per cluster data, which allowed a more precise analysis of each sample. Bulk RNA-sequencing (RNA-seq)

[0384] Illumina sequencing files (bcl-files) were converted into fastq read files using Illumina bcl2fast1 (v2.20) software deployed through BaseSpace using standard parameters. Low input RNA-seq data gene transcript counts were aligned to Homo sapiens GRCH38 (v2.7.4a) genome using STAR (v2.7.10a) to generate gene count files and annotated using ENSEMBL. Gene counts were combined into sample gene matrix files (h5).

[0385] Computational analysis was performed using the Scanpy (v1 .9.6) package. Two h5ad files were joined on the basis of similar features and genes. The two merged files were created into one Anndata object which was normalized to 10,000 UMI per sample and log (In) plus 1 transformed. Principal component analysis was performed using 30 PCA components. Projection into two dimensions was performed using the Uniform Manifold Approximation and Projection (UMAP) method.

[0386] The main focus of this analyses was the VCT clones, so the original object was subsetted into a smaller object containing the 9 VCT clones. A dot plot using Scanpy’s software, containing GC markers was generated for all the VCT clones to demonstrate gene expression in each. The scale was set to a maximum of 1 to ensure consistency amongst all samples.

[0387] Proteomics

[0388] Liquid chromatography followed by tandem mass spectrometry (LC-MS / MS) analysis was conducted on a series of samples, including RUO-hiPSC, CG-hiSC, RUO-OSC at time 0-hours (Oh) and after 24 hours (24h) of culture with supplemented MediCult IVM media. Supplemented IVM media consisted of MediCult IVM media supplemented with 75 mIU / mL recombinant FSH, 100 mIU / mL recombinant hCG, 500 ng / mL androstenedione, 1 pg / mL doxycycline, and 10 mg / mL human serum albumin (HSA). Two million cells were analyzed per condition.

[0389] Conditioned media derived from RUO-OSC and CG-OSC was also analyzed using LC-MS / MS. To generate conditioned media, 2 million OSC cells were cultured in 2 mL supplemented MediCult IVM media for 24 hours, maintaining the ratio of the intended clinical cell dose of 1 ,000 OSC cells per 1 pL of media. The cells were cultured for 24 hours in an incubator with CO2 set for a pH of 7.2-7.4. Following culture, OSC cells and conditioned media were separated and processed independently. Supplemented IVM media without OSCs was used as a media control. The media from each sample was subjected to consecutive centrifugations (300 x g, 1 ,200 x g and 3,000 x g) to remove cellular remnants, and then passed through albumin depletion columns to eliminate HSA from the samples.

[0390] Proteins from the samples were precipitated using acetone, re-suspended in 0.1% RAPIGEST™ SF Surfactant (Waters Corporation, Waltham, MA) and 25 mM ammonium bicarbonate, reduced with dithiothreitol, and alkylated with iodoacetamide, before undergoing in-solution trypsin digestion overnight at 37°C. The resulting peptides were desalted using C18 stage-tip columns prior to analysis using a ThermoFisher EASY-nLC 1200 coupled on-line to an Orbitrap FUSION™ LUMOS™ mass spectrometer (ThermoFisher). Buffer A (0.1% formic acid in water) and buffer B (0.1% formic acid in 80% acetonitrile) were used as mobile phases for gradient separation. For peptide separation, a packed in-house 75 pm x 15 cm chromatography column (ReproSil-Pur C18-A1 , 3pm, Dr. Maisch GmbH, Germany) was used. Peptides were separated with a gradient of 5-40% buffer B over 30 minutes, 40%-100% buffer B over 10 minutes at a flow rate of 400 mL / min. Fusion Lumos mass spectrometer operated in a data independent acquisition (DIA) mode, collecting MS1 scans in the Orbitrap mass analyzer from 350-1400 m / z at 120K resolution. The instrument was set to select precursors in 45 x 14 m / z wide windows with 1 m / z overlap from 350-975 m / z for HCD fragmentation. MS / MS scans were collected in the Orbitrap at 15K resolution.

[0391] To analyze the proteomic data, the human Uniprot database was searched using DIA-NN v1 .8 with filtering for 1% false discovery rate (FDR) for both protein and peptide identifications. Protein intensities were normalized and log transformed for relative quantitation and multiple hypothesis correction of p-values was performed using the Benjamini-Hochberg method.

[0392] Flow cytometry and immunofluorescence

[0393] Immunofluorescence staining was conducted on hiPSCs adhered to an ibidi slide, following the protocol recommendations from the New York Stem Cell Foundation (NYSCF). Briefly, hiPSCs were fixed in 2% paraformaldehyde (PFA) for 10 minutes, followed by a 30 minute blocking step in a blocking buffer (1X PBS containing 3% donkey normal serum and 0.1 % Triton-X). The primary antibodies used were mouse monoclonal antibody against OCT3 / 4 (1 :200; sc5279, Santa Cruz Biotechnology), goat polyclonal antibody against SOX2 (1 :50; AF2018, R&D systems), goat polyclonal antibody against NANOG (1 :50; AF1997, R&D systems), and Alexa Fluor 488 mouse monoclonal antibody against TRA-1 -60 (1 :100; 560173, BD Biosciences). The secondary antibodies used were Alexa Fluor 555 donkey anti-mouse IgG (A32773, Invitrogen), Alexa Fluor 488 donkey anti-goat IgG (A32814, Invitrogen). All antibody dilutions were prepared in blocking buffer and incubated at room temperature (RT) for 1 hour. After incubations, samples were washed 3 times for 30 minutes with PBS containing 0.1% Tween-20 (PBST). Nuclear staining was performed using the DNA marker DAPI (diluted 1 :1 ,000 in PBST) for 10 minutes. Subsequently, samples were mounted with Prolong Gold mounting medium prior to imaging using an ECHO Revolve microscope.

[0394] Flow cytometry analyses were conducted on RUO-OSC and CG-OSCs. For the analysis of live cells, cells were incubated with a PE-conjugated mouse monoclonal antibody against CD82 (1 :50 dilution; 342104, BioLegend) in FACS wash (dPBS with 5% fetal bovine serum (FBS)). After incubation, cells were washed with FACS wash, stained with propidium iodide (1 :20 dilution; P4864, Millipore Sigma) for live / dead cell staining, and subsequently analyzed using a CytoFlex Flow Cytometer. For the analysis of fixed cells, cells were fixed with 4% PFA for 15 minutes at RT and then washed with dPBS. After, cells were permeabilized using FACS wash solution containing 0.1% Triton X-100 (A16046.AE, ThermoFisher). The primary antibodies used were mouse monoclonal antibody against OCT3 / 4 (1 :50 dilution; sc5279, Santa Cruz Biotechnology), and rabbit polyclonal antibody against FOXL2 (1 :100 dilution; A16244, ABclonal). The secondary antibodies used were Alexa Fluor 555 donkey anti-mouse IgG (A32773, Invitrogen), and Alexa Fluor 488 donkey anti-rabbit IgG (A32790, Invitrogen). Following incubations, cells were washed with FACS wash containing Triton X-100, and then analyzed using a CytoFlex Flow Cytometer. Unstained cells (negative controls) were used to determine the gating strategy.

[0395] RT-qPCR and genotyping PCR

[0396] For genotyping PCR, DNA extraction from various hiPSC clones was carried out using the QuickExtract DNA Extract Solution (QE09050, Epicentre), following the manufacturer’s instructions. PCR amplification was performed using Q5® High-Fidelity 2X Master Mix (New England Biolabs, Ipswich, MA) for 35 cycles with a 20-seconds extension time. Subsequently, PCR was performed to validate the expression of the 3 transcription factors NR5A1 , GATA4, and RUNX2. The PCR protocol included an initial denaturation step at 98°C for 30 seconds, followed by 35 cycles of denaturation at 98°C for 10 seconds, annealing at 66-70°C for 10 seconds, and extension at 72°C for 20 seconds, with a final extension step of 2 minutes. The reaction was then held at 4°C. After, gel electrophoresis was performed to confirm the presence of TFs bands. Briefly, a 2% agarose gel was prepared using ultrapure agarose in TAE buffer. DNA gel staining was achieved by incubating the gel with 1 X SYBR™ Safe DNA gel stain (ThermoFisher) for 30 minutes. Following sample loading, electrophoresis was performed at 100V for 1 hour.

[0397] RT-qPCR was performed to assess gene expression markers. RNA extraction was performed using the QUICK-RNA™ Microprep Kit (R1051 , Zymo Research, Irvine, CA) following the manufacturer’s instructions. cDNA synthesis was carried out with the LUNASCRIPT® RT SuperMix Kit (E3010, New England Biolabs), using a thermocycler program consisting of a primer annealing stage at 25°C for 2 minutes, followed by cDNA synthesis at 55°C for 10 minutes, concluded with heat inactivation at 95°C for 1 minute. Quantification of RNA and cDNA was performed using Nanodrop. POWERUP™ SYBR™ Green Master Mix (100029284, Applied Biosystems) was used for RT-qPCR. The RT-qPCR protocol involved an initial denaturation step at 95°C for 2 minutes, followed by 40 cycles of denaturation at 95°C for 3 seconds, annealing at 60°C for 30 seconds, and an analysis step. Data analysis was performed.

[0398] Enzyme-linked immunosorbent assay (ELISA) of hormone secretion

[0399] To evaluate and compare the secretion of estradiol (E2) from various batches of OSC cells, OSCs were incubated for 24 hours at 37eC, 5% CO2 in DK10 media alone, or supplemented with 75 mIU / mL recombinant FSH, 500 ng / mL androstenedione, or a combination of both. Following the incubation period, conditioned media was collected and used for subsequent analyses. Estradiol levels were determined by ELISA using a commercially available kit (EIA2693, DRG International, Inc.), and ELISAs were performed according to manufacturer’s instructions.

[0400] Safety testing of cells

[0401] Mycoplasma testing was performed using > 5.0 x 105hiPSCs in duplicate. DNA was extracted from the cells, and RT-qPCR was performed for the direct detection of nucleic acid sequences corresponding to Mycoplasma pulmonis and Mycoplasma sp. as mycoplasma targets.

[0402] Endotoxin testing was performed on a thawed hiPSC sample using a quantitative kinetic chromogenic LAL (Limulus Amebocyte Lysate) assay in accordance with the USP <85> compendial method.

[0403] Sterility testing was performed to detect the presence of bacteria and fungi. A total of 100 pL of each cell sample was aseptically inoculated directly into vessels containing eight different media types and incubated for 10 days. The plates were then assessed for growth.

[0404] Adventitious agents testing was performed on > 5.0 x 105hiPSCs in duplicate. Adventitious agents testing included detection of the presence of the most common human adventitious agents (i.e ., infective agents): Adeno-Associated Virus (AAV), Human Parvovirus B19, BK Polyomavirus (BKPyV), Epstein-Barr Virus (EBV), Influenza A Virus Subtype H1 , Human Adenovirus (HAdV), Hantaan Virus, Human Cytomegalovirus (HCMV), Hepatitis A Virus, Hepatitis B Virus, Hepatitis C Virus, Human Foamy Virus (HFV), Human Herpesvirus 6 (HHV-6), Human Herpesvirus 8 (HHV-8, Kaposi’s Sarcoma- Associated Herpesvirus), Human Herpesvirus 7 (HHV-7), Human Immunodeficiency Virus Type 1 (HIV-

[0405] 1 ), Human Immunodeficiency Virus Type 2 (HIV-2), Human Papillomavirus Type 16 (HPV-16), Human Papillomavirus Type 18 (HPV-18), Herpes Simplex Virus Type 1 (HSV-1 ), Herpes Simplex Virus Type 2 (HSV-2), Human T-Cell Leukemia Virus Type 1 (HTLV-1 ), Human T-Cell Leukemia Virus Type 2 (HTLV-

[0406] 2), JC Polyomavirus (JCPyV), Merkel Cell Polyomavirus (MCPyV), Simian Virus 40 (SV40), and Varicella- Zoster Virus (VZV). DNA was extracted and RT-qPCR was performed for the direct detection of nucleic acid sequences corresponding to the foregoing agents.

[0407] In vitro maturation of oocytes

[0408] The oocyte maturation-stimulating potential of various OSC batches was used to evaluate the potency of each batch of manufactured OSCs. Briefly, immature oocytes surrounded by cumulus cells, known as cumulus-oocyte complexes (COCs), were retrieved from subjects that had undergone minimal stimulation protocols for oocyte retrieval. Subsequently, these COCs were co-cultured with different batches of OSC cells for 24-28 hours to facilitate in vitro maturation (IVM). Oocyte maturation rate was evaluated following the IVM culture period. See, e.g., Examples 5 and 9 for more details.

[0409] Murine oocyte maturation assay

[0410] Hybrid (B6 / CBA) females, and male mice from the same genetic backgrounds, were purchased from Janvier Labs. Upon arrival, all mice were quarantined and acclimated to the PCB Animal facility (PRAAL) for approximately 1 week prior to use. Mice were housed with a 12-hr I ig ht / dark cycle (lights on at 7:00 A.M.) with ad libitum access to food and water. All procedures involving mice, e.g., handling, administration of hormones for superovulation of females were conducted at the PRAAL Animal Facility, while procedures involving oocyte manipulation, e.g., oocyte collection, oocyte insemination and embryo culture up to blastocyst were performed at Embryotools’ laboratories.

[0411] A total of 10 mL of OSC-IVM media (i.e. , IVM media to be cultured with OSCs as described below), consisting of MediCult IVM Base Media, 10 mg / mL human serum albumin (HSA), 75 mIU / mL recombinant follicle stimulating hormone (rFSH), 100 mIU / mL human chorionic gonadotropin (hCG), 1 pg / mL doxycycline, and 500 ng / mL androstenedione was prepared and stored at 4°C until use. An IVM control medium consisting of 10 mL of MediCult IVM Base Media and the same additives was similarly prepared and stored. Plating dishes were prepared 16-24 hours prior to oocyte culture to allow for equilibration. The wells of a universal GPS dishes (UGPS-010, Cooper) were prepared with 50 pL LAG media, 100 pL OSC-IVM media, 100 pL MediCult IVM control media, or 50 pL OSC-IVM media / MediCult IVM control media for wash droplets. Then, 12 mL of mineral oil (Kitazato) was used to overlay droplets. All dishes were incubated overnight at 37°C with CO2 set for a pH of 7.2-7.4 and 5% O2.

[0412] On the day of oocyte culture, clinical grade OSCs were seeded 2-5 hours before co-culture, in which 50 pL of OSCs were added to the wells with OSC-IVM media, for a concentration of 100,000 OSCs in 100 pL media. The plate was then incubated for at least 2 hours until oocyte seeding.

[0413] Fresh immature mouse oocytes at the GV stage were collected from the ovaries of hybrid (B6 / CBA) females between 6 and 8 weeks of age stimulated with 7.5 IU pregnant mare serum gonadotropin (PMSG) 48 hours before retrieval. GVs with cumulus cells were then randomly split between the OSC-IVM group or the MediCult IVM control group. Oocytes were then plated and incubated at 37°C for 18 hours for IVM. After IVM, oocytes were stripped using hyaluronidase (H3884-50MG, Sigma-Aldrich) and assessed for maturity. Mature oocytes with first polar body extrusion were selected for intracytoplasmic sperm injection (ICSI). Fresh sperm from B6 / CBA hybrid strain mice was obtained in a microdroplet of culture medium and cultured for 15 minutes at 37°C, 5% CO2, and 5% O2. After incubation, 3 pL of the concentrated sperm solution was further diluted in a 150 pL droplet of the same culture medium. ICSI was performed using a piezo drill-based protocol optimized for the mouse species. Briefly, mouse sperm heads were isolated from the tail and injected into the mature oocytes. Following injection, the oocytes were thoroughly washed and cultured until day 5 (120 hours) in benchtop incubators at 37°C, 5% CO2, and 5% O2. Embryo development was monitored until the last day of culture.

[0414] Subject ages, ethics, and informed consent

[0415] This study was performed according to the ethical guidelines outlined in the Declaration of Helsinki. Oocyte donor participants were enrolled in the study at several fertility clinics, including the Ruber Clinic (Madrid, Spain), Spring Fertility Clinic (New York, USA), Extend Fertility Clinic (New York, USA), and Pranor Clinic (Lima, Peru), using informed consent for donation of gametes for research purposes, with ethical approval from CNRHA 47 / 428973.9 / 22 (Spain), Western IRB No. 20225832 (USA), and Protocol No. GC-MSP-01 (Peru), respectively.

[0416] OSC cell preparation

[0417] The morning of oocyte retrieval, cryopreserved OSCs were thawed, resuspended in supplemented IVM media, and washed twice using centrifugation and pelleting to remove residual cryoprotectant. Supplemented IVM media consisted of MediCult IVM media supplemented with 75 mIU / mL recombinant FSH, 100 mIU / mL recombinant hCG, 500 ng / mL androstenedione, 1 pg / mL doxycycline, and 10 mg / mL HSA. Androstenedione is supplemented into the media to recapitulate the role of theca cells and to facilitate estradiol (E2) production by the OSCs. Supplemented IVM media equilibrated overnight at 37eC with CO2 adjusted so that the pH of the bicarbonate-buffered medium was 7.2-7.3, with the 02 level maintained at 5% under mineral oil (Lifeguard, LifeGlobal) was used for final resuspension. OSCs were then plated in suspension, maintaining a concentration of 100,000 OSCs per 100 pL. The culture condition containing OSCs in supplemented IVM media was designated as OSC-IVM. As a control, a condition consisting only of supplemented IVM media (Medicult-IVM) devoid of OSC cells was also included in this study. Embryology dishes containing supplemented IVM media droplets were prepared a day before oocyte retrieval and allowed to equilibrate overnight in an incubator at 37eC with CO2 adjusted so that the pH of the bicarbonate-buffered medium was 7.2-7.3, with the O2 level maintained at 5% under mineral oil.

[0418] Oocyte retrieval and IVM culture

[0419] Immature oocytes at the GV stage were collected from the ovaries of subjects that underwent minimal stimulation protocols. These protocols adhered to standard practices, including (A) 3-4 days of stimulation using 325-600 IU of rFSH with a 10,000 IU of hCG trigger, (B) 5 doses of 100 mg of clomiphene citrate with an additional 1 -2 doses of 150 IU rFSH with or without a 2500-IU hCG trigger, or (C) 3 days of stimulation using 600 IU rFSH with a 2500-IU hCG trigger. Following oocyte retrieval, follicular aspirates were examined in the laboratory to search for COCs, which were transferred to an embryology dish containing pre-incubation LAG Medium and held until utilized for IVM. After, the collected immature COCs were subjected to OSC-IVM culture with various OSC batches or placed in the IVM control group. The IVM culture was performed in an incubator at 37eC with CO2 adjusted so that the pH of the bicarbonate-buffered medium was 7.2-7.3, with the O2 level maintained at 5%.

[0420] Assessment of oocyte in vitro maturation

[0421] After the 24- to 28-hour IVM culture period, COCs underwent stripping of surrounding cumulus and corona cells through hyaluronidase treatment. Subsequently, oocytes were evaluated for their maturation state and categorized into immature stages (Germinal Vesicles oocyte or Ml oocyte) or mature stage (Mil oocytes).

[0422] In vitro fertilization

[0423] After IVM, all COCs were moved out of the IVM culture dish and washed through at least 3 droplets to serially dilute residual IVM components and wash away residual OSCs. COCs were then treated according to standard IVF practice via hyaluronidase treatment to strip the cumulus cells and denude the oocyte. This stripping likewise removed any residual OSCs. All mature oocytes were fertilized using ICSI and cultured in group or single culture using single-step embryo culture medium. Assessment of the fertilization rate was performed at 16-18 hours post-ICSI, then at Days 3, 5, 6, and 7 post IVM. A standardized embryo grading system based on the classification system by Gardner & Schoolcraft (i.e., Gardner classification) was used on Days 5-7. Embryos that did not meet their respective checkpoints were discarded and blastocysts of freezable quality (Gardner grade >3CC) underwent vitrification. Embryos were hatched using laser-assisted hatching and underwent trophectoderm biopsy prior to vitrification on the day of freezing. Pre-implantation genetic testing for aneuploidy (PGT-A) was performed using microarray-based or SNP-based NGS analysis in local laboratories. Only embryos considered euploid were utilized for transfer. Low grade mosaicism, after consultation with a geneticist, were utilized for transfer depending on patient preference. The highest quality embryo was thawed later for frozen embryo transfer (FET) within 2 months of cryopreservation. Only single blastocyst transfers were allowed and all transfers were FET cycles.

[0424] For uterine priming, starting on the first day of menses, subjects received 2 mg oral estradiol treatment twice daily with an optional 100 pg patch replaced every three days until the endometrial thickness was >7 mm. Progesterone was then administered at 50 mg intramuscular once daily to prepare for ET or via a combination of intravaginal (800 mg) and subcutaneous progesterone. Progesterone could be increased to 100 mg daily if clinically indicated due to bleeding or a low progesterone level.

[0425] Following ET, serum beta human chorionic gonadotropin (BHCG) levels were measured 10-14 days post-transfer and followed until an appropriate rise was confirmed (2-3 days following 1 st confirmation), indicating a biochemical pregnancy.

[0426] Transvaginal ultrasounds were performed at 4-6 weeks gestation to establish the presence of a gestational sac, indicating clinical pregnancy, and a follow-up ultrasound was performed at 8-12 weeks of gestation to confirm ongoing pregnancy with a normal, healthy heartbeat. If a subject became pregnant, P4 and E2 administration were continued for up to 8-12 weeks of gestation.

[0427] Subjects that were pregnant following discharge from the clinic received a second trimester pregnancy ultrasound record at week 20-24, an anomaly scan performed by an OBGYN, and were assessed for any serious adverse events (SAE). Additionally, the clinic obtained birth data from the patient. Adverse events of special interest (AESI) such as response to stimulation and retrieval, ovarian hyperstimulation syndrome (OHSS), pregnancy loss, fetal anomalies, pregnancy complications, birth weight anomalies, birth defects, and neonatal complications were collected.

[0428] / ' / . Transcription factor mediated differentiation consistently generates ovarian support cells in different stages of ovarian development and folliculogenesis

[0429] To evaluate the feasibility of utilizing a gene-modified hiPSC line, harboring three inducible transcription factors (NR5A1 , RUNX2, and GATA4), as a source to generate consistent and functional OSCs, we compared 6 independent batches of hiPSC-derived OSCs differentiated across 8 months by multiple operators following a standard operating procedure. Differentiation of OSCs mediated by the overexpression of inducible transcription factors is a fast and straightforward process compared to standard protocols that rely on small molecules to recapitulate developmental trajectories. After 5 days of induction, hiPSCs multiply 5.63±2.85 times, and acquire morphological features that resemble human granulosa cells, such as clusters of cells with spiky edges and granules observed in the cell body (FIG. 1 A). Differentiated OSCs also express FOXL2 and CD82, two well-characterized markers of granulosa cell-fate, indicating successful differentiation into the desired cell type (FIG. 1 B).

[0430] To further characterize the molecular phenotype of the differentiated OSCs, as well as better understand differences and similarities among independent batches, we performed single cell RNA- sequencing (scRNA-seq) on cryopreserved samples from six batches of differentiation (FIG. 1 C). We identified 15 initial Leiden clusters that were combined by molecular similarities, resulting in nine final clusters. Among the 15 initial Leiden clusters identified, 12 of them expressed markers that are differentially expressed in human granulosa cells (GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, ITGB1 ) compared to other cell types in the developing ovary. These clusters were all identified as granulosa cells, and therefore assigned as the two major classes: Early GCs or GCs. The remaining three clusters were included in a third major class identified as Others, as expression of major granulosa markers was not evident in these groups of cells (FIG. 1 D).

[0431] Despite the expression of all the granulosa markers, the class assigned as Early GCs also shares transcriptional similarities to preGC-l and -lla / llb subclusters, including expression of the genes FOXO1 and CDH1 (FIG. 1 D). A subcluster of these cells, labeled as Early GC I expresses the aromatase gene, CYP19A1 , which has been described to be upregulated in preGC-ls in the ovarian medulla, as well as the gene for the chemotactic protein, RARRES2, which has been shown to reduce steroidogenesis and block oocyte meiotic progression in bovine models. The subcluster Early GC II also expresses the gene for RARRES2, similarly to the previous subcluster described, in addition to the receptor NOTCH2 (FIG. 1 D). The NOTCH signaling pathway is involved in the oocyte-GC crosstalk during folliculogenesis, and high levels of expression of NOTCH2 and NOTCH3 in cumulus cells have been positively correlated with IVF response. Finally, in the subcluster Early GC III, RARRES2 expression is no longer observed, as in the previous subcluster, while NOTCH2 expression continues to be detected in significant levels. Together, these patterns of expression suggest that the clusters in the Early GC class share transcriptional signature with both granulosa cells and preGC-l and -lia / lib, and differential expression of CYP19A1 , RARRES2, and NOTCH2, suggest a gradual developmental and functional progression from the subcluster Early GC I to Early GC III.

[0432] The class of GCs is marked by the expression of CDH2 in addition to all the other granulosa markers previously described, including the NOTCH2 / 3 receptors (FIG. 1 D). The subcluster GC I is enriched for the genes NRG1 , BMPR1 B, and genes of the ERBB family of receptors (FIG. 1 D). NRG1 has been identified to be differentially expressed in preGC-lla / l lb and was found to be expressed and secreted by granulosa cells in response to ovulatory surge. BMPR1 B, EGFR (ERBB1 ), and ERBB4 are all receptors identified in granulosa cells and have counterpart ligands expressed in oocytes (BMP6, TGFA, and NRG4, respectively). These interactions have been proposed to mediate follicular assembly. The subcluster GC II is enriched by expression of the gene ID3, which is a target of the receptor BMPR2, also expressed by these cells. Interestingly, although BMPR2 is expressed by all Early GCs and GC clusters, the CG II subcluster is the subcluster with the strongest enrichment of this target gene (FIG. 1 D), suggesting activation of the receptor BMPR2 in these cells. The last subcluster from the GC class, GC III, is composed of cells expressing both CDH2 and NOTCH2, but this subcluster is not enriched for any of the other genes previously described in the subclusters for this class. These data suggest that the three subclusters of GCs represent ovarian support cells in slightly different cell states that are mediated by a distinct combination of active signaling pathways.

[0433] The last three subclusters identified (Atresia / Luteolysis, Ribosomal enriched, and Mitochondrial enriched) were incorporated into a third class labeled as Others. These subclusters have overall lower expression of most markers including GJA1 and CDH2 (FIG. 1 E). Lower expression levels of GJA1 and CDH2 have been described in GCs undergoing early stages of atresia. Interestingly, cells on the Atresia / Luteolysis subcluster also express genes involved in steroidogenesis, such as CYP11 A1 , CYP19A1 , and HSD17B1 , as well as CGA, which is an estrogen receptor alpha-responsive gene in human breast cancer cells. The other two clusters are also enriched for the GCA gene, but the top expressed genes in each of the clusters are either mitochondrial genes in the Mitochondrial enriched subcluster or ribosomal genes for the Ribosomal enriched subcluster. Generally, enrichment of mitochondrial and / or ribosomal genes in scRNA-seq analysis is associated with poor quality cells, further suggesting that these clusters are composed of dying cells.

[0434] After identifying that most of the cells in our analysis are classified as granulosa cells (Early GCs and GCs), we sought to understand whether our protocol gave rise to OSCs in different stages of folliculogenesis or whether cells were overrepresented by a specific follicular stage. For that, we leveraged as a reference a published transcriptome landscape of human folliculogenesis to generate gene signature scores that were then applied to our samples. We did not observe a clear representation of either the Primary GC or Secondary GC stages within our samples, and most of the genes associated to these signature scores were not enriched in the analyzed cells. Conversely, the signature scores for Antral GC and Pre-ovulatory GC were more clearly represented within the clusters identified in our analysis, and multiple genes driving these signatures seem to be enriched by multiple clusters (FIG. 1 E).

[0435] Following characterization of the cellular outcome resultant from our differentiation process, we investigated the reproducibility and consistency of these methods across independent batches of hiPSC- derived OSCs. Overall, all batches analyzed consistently generated clusters from the 3 major classes previously described (Early GCs, GCs, and Others), five of which were very similar in terms of cluster distribution per batch (FIG. 1 F). These results demonstrate a consistent methodology of producing OSCs from reprogrammed hiPSCs for clinical use for ART or fertility treatments.

[0436] Hi. In vitro maturation of human oocytes is robustly achieved by multiple batches of hiPSC-derived ovarian support cells

[0437] We next sought to verify whether the functional readout of independent batches would have variable cellular outcome or have correlated cellular outcome. To assess the functional readout of OSCs, we leveraged IVM protocols (see also, e.g., Examples 5-7 below), in which OSCs are co-cultured with immature oocytes retrieved from individuals undergoing abbreviated gonadotropin stimulation and Mil formation was recorded as an endpoint of oocyte maturation (FIG. 2A). To capture the different spectrum of cell composition variability among the six batches analyzed by scRNA-seq, we performed functional analysis on lot 6, which was overall more represented by GC clusters; lot 8, which contained a balanced representation of Early GC and GC clusters; and lot 56, which was more represented by Early GC and Other clusters, with a lower contribution of the GC clusters (FIG. 1 F). We utilized state of the art media composition Medicult IVM that is typically used for IVM as the baseline control to assess positive functional readout of IVM induced by the addition of OSCs to the medium (FIG. 2A). For the initial analyses, oocytes retrieved from each donor were split into the two conditions (Control-IVM and OSC- IVM) prior to maturation and Mil formation rate is recorded among the different groups. We demonstrated that all the three individual batches analyzed successfully led to higher MH formation rate as compared to the control (p=0.021 , lot 6 / control: 1 .37, lot 8 / control: 1 .31 , lot 56 / control: 1 .28) (FIG. 2B). These results indicate that variable cellular outcomes robustly retain the ability to improve human oocyte maturation rate compared to control, suggesting that both GC and Early GC OSC clusters may contribute to oocyte maturation.

[0438] To gain insight into the potential mechanism of action associated with these IVM results, we analyzed the expression of key receptors, ligands, and target genes that have an important role in oocyte and ovarian support cell interactions and compared this expression among different classes of cells identified in our samples. Comparison of relative expression of multiple pairs of ligand and receptors indicates that GC and Early GC clusters express relatively higher levels of BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46, suggesting a potential involvement of one of these elements as part of the mechanism of action of these cells (FIG. 2C). Other receptors such as STRA6, ERBB4, RARRES2, and EGFR, were also detected particularly in the Early GC clusters, suggesting that these genes may not be the primary drivers of oocyte maturation (FIG. 2C). Additionally, we assessed the expression of growth factors that are modulated by oocyte-somatic cell interactions and play a role in oocyte maturation and folliculogenesis. Among the genes differentially expressed across clusters, TGFB1 and TGFB2 were more enriched in the GCI cluster, while VEGFA and VEGFB, in addition to BMP7 and PDGFA, were generally more abundant in the Early GC cluster (FIG. 2D). The Early GC and GC clusters were enriched for IGF2BP1 , IGF2BP2, and IGF2BP3 (FIG. 2D). iv. Translation of the protocol towards clinical manufacturing leads to more reproducible cellular outcomes

[0439] As part of the strategy to translate the research manufacturing protocol towards clinical standards, we performed a risk assessment on our bill of materials, which led to the substitution of key components of the protocol by higher quality alternatives, including animal origin free reagents, GMP manufactured components, and cell-therapy grade raw materials (FIG. 3A). We further sought to understand additional factors and reagents as variables that influence OSC differentiation to drive greater optimization and ensure reproducibility at the manufacturing stage for improved efficacy and safety. We investigated the combined effects of the inducible transcription factors with media supplements and cell substrates in the growth media environment. Because small molecule-mediated differentiation in supplemented media can generate ovarian cell types from iPSCs, we compiled potential factors and small molecules that may influence OSC differentiation, these factors including categories such as basal media, serum replacement, small molecules, and growth factors or morphogens, including relevant concentration ranges for each factor. Additionally, the matrix substrate on which cells grow can influence a range of factors for iPSCs in culture, including differentiation. We further included in our compiled factors schemes for inducing transcription factor expression, including doxycycline concentration and duration of doxycycline treatment. To systematically evaluate the effects of multiple variables simultaneously, we employed Design of Experiments (DOE) to create a custom design that included center points for each factor and was optimized for D-optimality criterion, which is an experimental design matrix that allows us to maximize efficiency and accuracy and minimize uncertainty in the response parameters. For responses in the design, we chose FOXL2 expression and viability, as FOXL2 is a biomarker of OSCs and viability screens for factors that are essential for manufacturing.

[0440] We demonstrate that the cell substrate has a clear and strong influence on FOXL2 expression that is far greater than any other variable (FIG. 3B; p-value < 0.01 ). These results emphasize the importance of substrate matrix selection for iPSCs differentiation. The DOE study further demonstrates that the duration of doxycycline treatment is an important factor, while doxycycline concentration is not as significant. Controls that include doxycycline-free treatment groups demonstrate a positive correlation between doxycycline and FOXL2 expression, underscoring the necessity of transcription factor induction and providing further validation of our TF-mediated methodology. Additionally, chemical antioxidant supplementation in the medium negatively impacted cellular viability and was subsequently excluded from manufacturing. These results confirm that transcription factors drive differentiation independent of added small-molecule components. Interestingly, these data regarding cell substrate influence led us to further optimize substrates for producing desired OSCs from iPSCs.

[0441] Among all the raw materials utilized during the generation of OSCs for research purposes, one of the reagents with the highest complexity was Matrigel, which is derived from Engelbreth-Holm-Swarm mouse sarcoma cells and contains multiple extracellular matrix components of tissue basement membranes. Due to the source and inherent complexity of this reagent, as well as the nature of its production, Matrigel has significant lot-to-lot variability, which can impact the overall reproducibility of the final differentiated cell product (e.g., OSCs). Alternative matrix substrates for hiPSC cultures include human recombinant laminin-521 and vitronectin.

[0442] We proceeded by directly comparing differentiation of hiPSCs that were cultured on either a substrate of human recombinant laminin-521 or vitronectin. Initial assessment of cellular morphology during the differentiation process indicated subtle differences between the experimental groups (FIG. 3C). Vitronectin-OSCs presented a larger cell body and organized themselves in more sparse clusters of cells, while laminin-OSCs were smaller and organized into compact groups of cells (FIG. 3C). Expression of CD82 was consistent between the two groups (FIG. 3D). To better understand the molecular profile of OSCs produced by these different matrix conditions and the reproducibility, we performed scRNA-seq in two batches of laminin-OSCs and two batches of vitronectin-OSCs and compared these data to our initial datasets (FIG. 3E-F). Laminin-OSCs are mostly distributed among subclusters GC I, GC II, GC III (FIGS. 3E-F). In contrast, vitronectin-OSCs are primarily represented by Early GC II, Early GC III, and GC III subclusters (FIGS. 3E-F). Notably, OSCs differentiated in media with vitronectin matrices had a higher percentage of cells in Mitochondrial enriched and Ribosomal enriched subclusters (FIGS. 3E-F). Interestingly, expression of N-cadherin (CDH2), a hallmark of GC subclusters that is not present in the Early GC subclusters, has been described to protect granulosa cells from apoptosis associated with follicular atresia and luteolysis. Additionally, vitronectin has been demonstrated to be upregulated in porcine atretic follicles. Collectively, these data suggest that there is an association between vitronectin matrices and higher percentages of cells in the Others class (i.e., Mitochondrial enriched, Ribosomal enriched, atresia / luteolysis).

[0443] Despite the differences observed in cellular outcome generated from these two matrix conditions, we did not observe major differences in cluster distribution among the two independent batches therein (FIGS. 3G-H), suggesting that changes in the bill of materials to include higher quality reagents yields consistent and reproducible cellular outcomes, independent of the matrix utilized. It is also important to highlight that each independent batch of differentiation was performed by a different operator, which strengthens the evidence of reproducibility. Importantly, these results demonstrate that the final OSC fate is impacted by not only the overexpression of the three transcription factors but is also significantly influenced by matrix utilized as the substrate during differentiation (FIGS. 3G-H). v. Differentiation over lamin in-521 leads to a scalable, pure, and functional population of ovarian support cells

[0444] After ensuring that transition to an overall higher quality bill of materials does not negatively affect reproducibility or final cellular outcome, we sought to investigate which of the two conditions (laminin-521 and vitronectin) yields better clinical outcomes for optimal clinical manufacturing. As a measurement of successful clinical outcome, we considered a few parameters that would directly inform throughput, safety, and potency of each condition. For throughput, we compared the ratio of OSC:hiPSC for each batch that was analyzed per condition (Table 1 ). The condition that yields more viable cells at the time of harvest, without changing the initial cell number or surface area of the cell culture, would be more scalable. Laminin-OSCs were harvested at 94.63±0.01% viability and during differentiation were multiplied at a ratio of 14.83±4.48 OSC:hiPSCs (Table 1 ). In contrast, vitronectin-OSCs were harvested at 87.00±0.08% viability and were multiplied at a ratio of 6.49±1 .43 OSC:hiPSC. (Table 1 ).

[0445] Table 1 : Ovarian support cell batch production and specifications

[0446] Abbreviations: RUO: research-use only; hiPSC: human induced pluripotent stem cells; M: Matrigel; V: vitronectin; L: laminin; OSC: ovarian support cells; CG: clinical-grade; XF: xeno-free; OP: operator

[0447] We next investigated whether the final cellular composition was functional and could promote maturation of human oocytes. We co-cultured both laminin-OSCs and vitronectin-OSCs independently with immature human oocytes following a similar approach discussed herein (see, e.g., Example 5) and scored the yield of oocyte maturation in each group. Co-culture with laminin-OSCs and vitronectin-OSCs led to a higher MH formation rate compared to the control (p=0.018, lot 41 / control:1 .08, lot 49 / control: 1 .36, lot 86 / control: 1 .27) (FIGS. 4A-B). Although both approaches seemed to have generated functional OSCs that contributed to successfully increasing oocyte maturation rate compared to control conditions, the vitronectin-OSC condition resulted in variable functional outputs (FIG. 4B). Overall, although Mil formation rates were slightly higher in the laminin-OSCs group comparatively, both approaches generated functional OSCs that contributed to successfully increasing oocyte maturation rates as compared to control media-only conditions.

[0448] Despite the overall higher rates of MH maturation in both laminin-OSC and vitronectin-OSC compared to control, it is clear that these two conditions are composed of cells with different phenotypic compositions (FIGS. 3C-H) and may drive oocyte maturation through different mechanisms. To further investigate potential OSC-oocyte interactions and involvement of key signaling pathways associated with follicle assembly and oocyte meiotic progression, we utilized data from endogenous tissue, to characterize how these genes were expressed in OSCs from each condition (FIGS. 4C-D). Overall expression of ligand-receptor patterns was similar between vitronectin-OSC group and laminin-OSC group, with BMPR1 B slightly more enriched in the laminin-OSC group compared to the vitronectin-OSC group (FIG. 4C). This suggests that distinct subgroups of cells (i.e., Early GC and GC clusters) are likely equally receptive to paracrine and / or autocrine signaling. Comparison of expression pattern of growth factor genes among both groups indicates a few differences (FIG. 4D). For instance, VEGFA and VEGFB as well as PDGFA were more enriched in the Early GCs and therefore more enriched in the vitronectin- OSC samples. In contrast, BMP7 had greater expression in the Early GC II, GC I, and GC III clusters of the laminin-OSC samples (FIG. 4D). Interestingly, both BMP4 and BMP7 are proposed to differentially regulate FSH-dependent estradiol and progesterone production, suggesting a potential contribution to the OSC-laminin mechanism of action. vi. Generation of a clinical-grade hiPSC line with the ability to generate functional ovarian support cells

[0449] The preceding experiments in this Example were performed with the hiPSC line GC3, which is a cell line that is designated for research-use-only (RUO) and not a clinical-grade cell line. Thus, we next sought to generate a clinical-grade hiPSC line from an allogeneic female donor for commercial clinical- grade materials. To minimize discrepancies between the results from the clinical-grade hiPSC line and the original RUO hiPSC line, which provided the foundation for initial preclinical studies and potency tests, we applied the same manufacturing strategy as the RUO hiPSC line to generate the clinical-grade hiPSC line.

[0450] The clinical-grade hiPSC line (CG-hiPSC) was engineered to harbor inducible versions of the three transcription factors that drive differentiation into OSCs, namely NR5A1 , RUNX2, and GATA4. Individual clones were generated by limiting dilution of the pooled engineered population and then expanded into seed banks. Clones that were successfully expanded were initially screened by genotyping PCR to confirm the integration of the three transcription factors (FIG. 5A). Nine seed clones harboring all the transcription factors were selected to proceed with a more in-depth screening process, which included assessing their identity, potency, and safety. To this end, each clone was individually differentiated into OSCs (FIG. 5B), to identify lead candidate clones. To specifically assess clonal identity, we verified expression of the OSC markers, FOXL2 and CD82 after 5 days of differentiation and confirmed that despite minor expression level variability among clones, all clones were positive for both markers, indicating successful generation of OSCs (FIG. 5B). Moreover, we confirmed that the level of the hiPSC marker OCT4 was null or very low to verify efficient and pure OSC outcome (FIG. 5B).

[0451] As a functional readout of individual clones, cells were differentiated for 5 days and exposed to follicle stimulating hormone (FSH, #2), Androstenedione (A4, #3) or a combination of both (FSH+A4, #4) hormones for 48 hours (FIG. 5C). Functional OSCs generate estradiol (E2) in response to FSH, and A4 is used as a substrate by the OSCs to complete the reaction. We observed that individual clones had variable responses following treatment with FSH+A4. Clones that were more responsive generally exhibited improved performance while maturing immature human oocytes (FIG. 5C). Treatment with FSH or A4 (#2 and #3) alone enable identification of clones that are intrinsically steroidogenic, which is an indication of an immature profile. To gain a more comprehensive overview of the molecular signature of the individual clones, we performed bulk RNA-sequencing of all clones individually and assessed expression of granulosa cell markers, as well as hiPSC cell markers (POU5F1 and NANOG) (FIG. 5D). All clones robustly expressed established granulosa cell markers (FOXL2, STAR, GJA5), including genes related to important signaling pathways (NOTCH3, HES1 , ID3, KITLG) (FIG. 5D), suggesting that despite the functional differences observed among clones (FIG. 5C), differences in marker gene signatures were less pronounced among CG-OSC clones. Based on the attributes previously described, in addition to the ratio OSC:hiPSC and viability at harvest, we identified the clone 2-D10 as the top lead candidate (hereafter referred to as CG-hiPSC) (FIG. 5E). This selection of the top candidate is primarily based on levels of FOXL2 and CD82 expression, as well as its responsiveness to FSH and A4 as measured by E2 production (FIG. 5E).

[0452] Because the OSCs are derived from hiPSCs, key safety considerations extend beyond attributes that are starndard for products for use in IVF and ART procedures (e.g., sterility, endotoxin levels, and embryotoxicity). Critical clinical safety considerations include the presence of residual hiPSCs, communicable diseases, and disease-related agents. Under controlled conditions, exemplary OSC lots (lot 88, lot 90, and lot 116) and two additional lots (lot 180 and lot 182) were assessed and compared based on OSC identity (as determined by CD82 and FOXL2 expression of the cell population), viability, residual hiPSCs (as determined by TRA-1-60 expression of the ceii population), mycoplasma detection, endotoxin detection, sterility, and detection of human pathogens to ensure safety of the clinical product (Table 2). These results confirm reproducibility for manufacturing clinical grade OSCs according to the described TF-directed methods and further demonstrate the clinical safety of the produced OSCs.

[0453] Table 2: Product Analysis of OSC Lots

[0454] NG= no growth; ND= not detected vii. Clinical-grade hiPSC line generated for clinical manufacturing shows reproducible differentiation and comparable molecular profiling to the research-use only cell line

[0455] To further characterize CG-hiPSC for clinical applications, we assessed and confirmed the presence of hiPSC markers, as well as confirmed cell identity and normal karyotype. We then generated two independent batches of differentiated CG-hiPSC, leveraging the protocol previously identified as the most appropriate to be transitioned into clinical manufacturing. More specifically CG-hiPSCs were differentiated on dishes coated with a laminin-521 matrix. As expected, cell morphology upon differentiation was characterized by small cells with granules in the cell body, tightly packed into clusters with spiky edges (FIG 6A). We also confirmed that viability at harvest remained high, averaging 96.90±0.00%, and that the ratio of OSC:hiPSC was similar to the ratio achieved with the RUO hiPSC line when differentiated over laminin-521 (14.83±4.48), averaging at 11.41 ±2.19. Identity of OSCs was confirmed by FOXL2 and CD82 expression. Moreover, hiPSC markers POU5F1 and NANOG were not detected following differentiation, further confirming OSC cellular identity and indicating the cell populations were not contaminated with residual hiPSCs (FIGS. 6B-C).

[0456] To further characterize the transcriptional signature of the differentiated OSCs, as well as assess reproducibility among independent lots, we performed scRNA-seq of two batches of differentiated CG- OSC-L (FIG. 6D). Strikingly, when compared with previous samples analyzed, the two batches were nearly identical in terms of cluster distribution, and they were composed primarily of GC class clusters, particularly subclusters GC I and GC III (FIGS. 6E-F). Interestingly, the transcriptomic profile of the OSCs derived from CG-hiPSC resembled the batch of the RUO hiPSC line that was initially generated (RUO- OSC-M lot 6 (FIGS. 1 C, 1 F), as well as the two batches of laminin-OSCs that generated after the raw material optimization (FIG. 3H). These results demonstrate successful hiPSC reprogramming into OSCs among independent batches of cells, independent of genetic backgrounds (RUO and clinical-grade hiPSC lines), and independent of operators. These data collectively demonstrate promising clinical utility of these cells and this methodology of hiPSC differentiation for ART and IVF applications.

[0457] To expand our analysis beyond transcriptomics readouts, we performed proteomics of the bulk population of differentiated OSCs derived from both CG-hiPSC and RUO-hiPSC. We included in our analysis samples of undifferentiated hiPSCs from both genetic backgrounds. Despite the limited detection range of this assay compared with RNA sequencing, inclusion of these additional samples in the analysis can provide insight into the differentiation process and the mechanism of action. To assess proteins and pathways that are upregulated during differentiation, we calculated the ratio of expression of each detected entity in OSCs and hiPSCs for both genetic backgrounds. Among the top 200 proteins detected with a higher ratio of expression in OSCs compared to hiPSCs, 26 were overexpressed in both cell lines and had enrichment in functional profiling terms such as cell-cell adhesion mediator activity, cytoskeleton organization, and focal adhesion (FIG. 6H), suggesting that these processes are involved with OSC differentiation. Interestingly, terms related to cytoskeleton remodeling and cell adhesion were not just enriched on the shared 26 proteins by both cell lines, but also on the total top 200 proteins from each genetic background, emphasizing the importance of these processes throughout the differentiation into OSCs. Additionally, comparison of RUO-OSC and CG-OSC secretome has demonstrated high correlation between these samples, further supporting comparability between both cell lines, and suggesting potential functional similarities (FIG. 6I). v / 77. Ovarian support cells derived from clinical-grade hiPSCs consistently lead to higher rates of oocyte maturation

[0458] To further assess the comparability between CG-OSC and RUO-OSC in terms of functional outcomes, we cultured three independent batches of CG-OSC-L with immature human oocytes and evaluated the rate of MH formation relative to the control group (FIG. 7A). We observed that all the three batches successfully led to higher rates of Mil maturation compared to the control (p=0.019, lot 88 / control:1 .24, lot 90 / control: 1 .22, lot 116 / control: 1 .29) in a very consistent manner (FIGS. 7A-B). Notably, the relative values compared to control from these three individual batches were also very similar to the relative value of RUO-OSC-L indicating that differentiation onto laminin-521 is not only reproducible among independent batches from the same cell line, but also across different genetic backgrounds (RUO-hiPSC and CG-hiPSC, FIG. 7B). Analysis of expression of key receptor-ligand components revealed overall enrichment of the receptors TGFBR1 , BMPR1 B, BMPR2, NOTCH2 / 3, ERBB4, and EGFR, as well as the ligands EFNB2, EFNB3, NRG1 , and NTN1 (FIG. 7C) within the CG- OSC batches. Notably, expression of TGFBR1 , BMPR2, NOTCH2, NOTCH3, and EFNB2 were particularly consistently enriched among OSC batches (FIGS. 2C, 4C, and 7C), indicating their potential involvement in the OSC mechanism of action. Furthermore, growth factors identified as enriched in previous batches (FIGS. 2D and 4D), such as FGF2, TGFB1 , and BMP7 were also enriched in the CG- OSC-L (FIG. 7D), suggesting their pivotal role in the oocyte maturation process. This is consistent with the involvement of these growth factors in orchestrating oocyte maturation through the interplay between granulosa cells and oocytes.

[0459] To gain insight into the potential mechanism of action of these cells during oocyte maturation beyond transcriptomics readouts, we also investigated proteins that were being overexpressed in OSC after 24 hours in vitro in comparison with OSC prior to culture (0 hour) from cells derived from both CG- hiPSC and RUO-hiPSC. Through a similar approach, we compared the top 200 proteins overexpressed in each genetic background and identified 40 commonly overexpressed proteins in both groups. These shared proteins were enriched for functional profiling terms such as transporter activity, electron transfer activity, aerobic respiration, and cellular lipid metabolic process (FIG. 7E). Analysis of the top 200 proteins in each group independently underscored terms associated with metabolic processes, consistent with the fundamental processes of glucose and lipid metabolism in granulosa cells to ensure healthy oocyte development. ix. Murine oocyte maturation model

[0460] To assess the potency of CG-OSCs, a murine oocyte maturation assay was developed to mimic clinical application using mice as a surrogate species. In this assay, which is outlined in (FIG. 8A), fresh immature mouse oocytes from hybrid strain B6 / CBA mice at the germinal vesicle (GV) stage were collected from minimally stimulated female mice between 6 and 8 weeks of age. The oocytes were then subjected to IVM in MediCult IVM Media (Media Only Control) alone or in the presence of different types of cells, including different OSC lots, he at- in activated CG-OSCs, and mouse embryonic fibroblasts. Following IVM, the oocytes were matured via intracytoplasmic sperm injection (ICSI). After five days, blastocyst formation rate (BFR) was assessed as a measure of potency.

[0461] In the three negative control conditions of media only IVM, co-culture with heat-inactivated CG- OSCs, and co-culture with mouse embryonic fibroblasts, the BFRs were relatively consistent at 59%, 58%, and 61%, respectively. Therefore, the observed improvement in BFR with OSC-IVM was due to the specific activity of OSCs (FIG. 8B). To evaluate the impact of dose on OSC-IVM efficacy, in one condition, half of the preferred number of OSCs (50,000 OSCs per 100 pL) was added during IVM coculture. In this condition, there was a substantial reduction in BFR as compared to the full dose of 50,000 OSCs per 100 pL of media, at 65% vs. 81%, respectively, demonstrating the importance of the number of OSCs in OSC-IVM (FIG. 8B). To confirm robustness of the process with respect to OSC potency, OSCs derived from different genetic backgrounds (RUO-hiPSC and CG-hiPSC) in vitro were evaluated based on BFRs following OSC-IVM with RUO-OSC-M, RUO-OSC-V, RUO-OSC-L, or CG-OSC lots. All OSC conditions exhibited an increased BFR compared to the negative control conditions, with the highest BFRs seen with the CG-OSC lots (FIG. 8B). Based on these results, the acceptance criteria for the CG- OSC test article was set as BFR (Day 5) > 60% and BFR (Day 5) Test Article > BFR (Day 5) Media Only Control. x. Safety and efficacy of clinical grade ovarian support cell for in vitro applications in humans To ensure good manufacturing practice (GMP) readiness, the CG-hiPSC Seed Bank was expanded into a Master Cell Bank (MCB) under GMP-compliant conditions. Aseptic process simulations (APS runs) were conducted to validate sterility, assess potential contamination risks, and confirm the robustness of the manufacturing process before full-scale GMP production.

[0462] A comprehensive risk assessment was performed on all materials and process steps involved in the CG-hiPSC to CG-OSC manufacturing workflow. The results of the risk assessment tests demonstrated that following CG-hiPSC expansion under GMP conditions confirmed that the manufacturing process had been sufficiently de-risked, supporting the progression of OSCs to GMP manufacturing and the subsequent release of GMP Fertilo batches for OSC-IVM application (Table 3).

[0463] Table 3: Clinical Safety of Cells xi. Clinical study with ovarian support cells significantly improves in vitro maturation outcomes

[0464] After establishing a cl inical ly-suitable OSC cell product, the clinical application of the OSCs was evaluated in a two-phase longitudinal cohort analysis: phase I consisted of a single arm multi-center observational study to evaluate safety (FIG. 9A), and phase II consisted of an expanded comparative study against traditional media-only IVM to measure efficacy of IVM with OSCs following a minimal follicular stimulation protocol (FIG. 9B).

[0465] In phase I of the study, twenty infertile patients under the age of 37, who had high ovarian reserve as determined by a measured AMH level of greater than 2 ng / mL, were recruited for a single arm, multi-center observational study to assess safety. Patient demographics and treatment conditions are shown in Table 4 below.

[0466] Table 4: Patient Demographics and Treatment Conditions of Phase I Study

[0467] SEM = standard error of the mean; hMG = human menopausal gonadotropin; OPU = oocyte pick up; BMI = body mass index; AFC = antral follicle count; PCOS = polycystic ovary syndrome

[0468] Following COC retrieval and IVM in the OSC and oocyte co-culture, key embryological and clinical outcomes were assessed. First, the MH maturation rate was determined to be 69% per COC retrieved based on the presence of a first polar body (PB1 ) (FIG. 10A). At 16 to 18 hours following ICSI, the fertilization rate was measured as 84% per mature MH oocyte, as determined by the formation of two pronuclei (FIG. 10A). The cleavage rate was determined on day 3 post-ICSI based on the presence of two or more cells, and the blastocyst formation rate was determined on days 5, 6, and 7 post-ICSI based on cavitation. For each fertilized embryo, the calculated cleavage rate and blastocyst formation rate was 96% and 43%, respectively (FIG. 10A). The euploidy rate for each blastocyst biopsy was 65%, which was determined via pre-implantation genetic testing for aneuploidy (PGT-A) analysis within seven days after ICSI (FIG. 10A). Finally, biochemical pregnancy (i.e., implantation) and clinical pregnancy rates were determined for each embryo transfer. Biochemical pregnancy was assessed at day 10-14 after embryo transfer based on a measured p-hCG level of >5 mIU / mL, and clinical pregnancy was assessed via ultrasound at a minimum of 5 to 7 weeks following embryo transfer based on the presence of a visible gestational sac with a normal fetal heartbeat at 7 weeks gestation. The rate of successful implantation was 64% for the OSC-IVM group, and the rate of clinical pregnancy was 45% (FIG. 10A). Notably, the first live birth of a healthy singleton female following an OSC-IVM treatment cycle with the OSCs occurred at 38.5 weeks. The baby was 3,255 grams at birth, 49.5 cm, and scored a 9 / 9 on the Apgar scale, demonstrating no abnormalities after a natural vaginal birth (FIG. 10B).

[0469] After verifying the safety of clinical grade OSCs with a minimal stimulation regimen and collecting measures of clinical success rates, an expansion of this study was performed. In the second phase, a limited comparator-controlled cohort evaluation of the clinical OSCs vs traditional IVM (monophasic IVM medium, MediCult) in a single center, 1 :1 randomized study was performed in twenty infertile patients (ten per treatment arm) who were 37 and younger and were determined to have levels of AMH >2 ng / mL. Patient demographic information of both male and female partners seeking an ART procedure and treatment conditions are provided in Table 5.

[0470] Table 5: Patient Demographics and Treatment Conditions of Phase II Study

[0471]

[0472] OCP = oral contraceptive pill; AFC = antral follicle count; TSH = thyroid stimulating hormone; SHBG = sex hormone binding globulin Adverse events related to minimal stimulation were considered non-treatment related, as treatment in all cases consisted of ex vivo oocyte maturation after oocyte retrieval (Table 6).

[0473] Table 6: Adverse Events for OSC-IVM and Traditional Media-Only IVM

[0474] OSC-IVM had an improved treatment success rate compared to traditional media-only IVM, and had a rate of ongoing pregnancies in patients of 37% as compared to the rate of 20% of ongoing pregnancies in the traditional media-only IVM group. In addition, although the blastocyst and euploid blastocyst rates were the most similar in the outcome comparison per COC, comparison of these rates per cycle shows that IVM with the clinical grade OSCs led to substantially more successful blastocyst and euploid blastocyst formation per cycle than traditional IVM using only culture medium (blastocyst 89% vs 60%; euploid blastocyst 79% vs 30%).

[0475] The efficacy of the OSC-IVM protocol was compared to that of traditional media-only IVM based on embryological endpoints for the retrieved oocytes (FIG. 10C). Following IVM, the MH maturation rate was determined, and the Mil maturation rate of the OSC-IVM group was significantly higher than that of the traditional media-only IVM group (70±7% vs 52±7%, p=0.0047; FIG. 10C). The Mil oocytes were then fertilized via ICSI, and, like the maturation rate, the fertilization rate per oocyte was significantly greater in the OSC-IVM group as compared to the traditional media-only IVM group (52±7% vs 30±5%, p=0.0004; FIG. 10C). On day 3 post-ICSI, the rate of cleavage (i.e., cell division following fertilization) of fertilized oocytes in the OSC-IVM group was nearly double the observed rate of cleavage in the traditional media- only IVM group, as determined by the presence of two or more cells (51 ±6% vs 28±4%, p=0.0002; FIG. 10C). The overall blastocyst, high quality (HQ) blastocyst, and euploid blastocyst formation rates were determined within seven days following ICSI. The rate of blastocyst formation in the OSC-IVM group was higher than that in the Traditional IVM group (p=0.061 ; FIG. 10C); however, strikingly, when considering only HQ blastocysts (i.e., blastocysts with a score of 3CC or greater based on the Gardner Scale) the OSC-IVM group had a significantly higher rate of HQ blastocyst formation than the traditional media-only IVM group (14±3% vs 7±2%, p=0.0135; FIG. 10C). Lastly, the euploid blastocyst formation rate was determined based on PGT-A analysis was determined, and the OSC-IVM group had a rate of euploid blastocyst formation that was five times greater than that of the traditional media-only IVM group (10±3% vs 2±1%, p=0.004; FIG. 10C). Notably, in this comparison, 8 of 10 patients in the OSC-IVM group obtained at least one euploid blastocyst for uterine transfer as compared to only 3 of 10 patients in the traditional media-only IVM group. Collectively, OSC-IVM demonstrated consistently improved outcomes compared to traditional media-only IVM outcomes for each minimal stimulation cycle (FIG. 10D).

[0476] Example 2. A method of producing ovarian support cells from iPSCs

[0477] This example demonstrates how iPSC differentiation (e.g., reprogramming or engineering) to one or more types of ovarian support cells may be effectuated. It is to be understood that this example is a non-limiting embodiment of the present disclosure, intended to describe potential protocols for manufacturing OSCs from iPSC precursors. iPSCs (e.g., hiPSCs) from a previously freeze-stored stock or freshly sourced from a donor subject are cultured in vitro in a suitable culture dish that contains cell media (e.g., in vitro maturation (IVM) cell media) and a matrix such as a matrix that comprises laminin. The undifferentiated hiPSCs are reprogrammed using a transposase expression plasmid (e.g., a piggyBac transposase method) to carry specific inducible transcription factors (e.g., FOXL2, NR5A1 , RUNX2, and / or GATA4). The transposase expression plasmid was electroporated into the hiPSCs. The transcription factors were induced upon application of doxycycline to the media. Wnt / p-catenin pathway activators including a ROCK inhibitor (e.g., Y-27642) and a GSK3 inhibitor (e.g., CHIR099021 ) were also added to the media to prime the cellular environment for mesodermal cell fate.

[0478] The cells are induced for about 5 days (e.g., about 2 days, about 3 days, about 4 days, about 5 days, about 6 days, about 7 days). Over the course of the reprogramming, expression of genes or biomarkers that correspond to one or more types of OSCs are assessed. Expression levels of mRNA and protein as assessed by RT-PCR and flow cytometry confirm that a portion population of cells express FOXL2 and AMHR2, and a separate portion of the cells express NR2F2, as compared to a population of hiPSCs that were not differentiated, thereby confirming that the hiPSCs differentiated into a mixed population of granulosa and ovarian stroma cells. Additionally, the resulting OSCs produce steroids such as estradiol and / or progesterone upon stimulation with androstenedione and FSH or forskolin. Production of steroids is confirmed via ELISA in which the steroid levels secreted in the cell media are measured with antibodies that detect the one or more steroids and compared to media from a sample with undifferentiated hiPSCs as a negative control.

[0479] Further, cell identity and relative purity of the resulting OSCs is confirmed by RT-PCR, in which no significant detection of one or more markers of pluripotency (e.g., POU5F1 , NANOG, SOX2, and / or OCT4) are detected relative to expression levels detected in undifferentiated hiPSCs, a positive control. Relative purity is further confirmed by low (e.g., less than 5%) or no detectable binding of an antibody specific to TRA-1 -60 or TRA-1 -81 , which are surface expression markers of undifferentiated pluripotent stem cells, to the resulting OSCs compared to undifferentiated hiPSCs, as measured by flow cytometry. Detected expression levels of pluripotency markers that are less than about 5% (e.g., less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, or less than 0.10%) of the expression levels of hiPSCs confirms that the resulting OSC population are pure and the hiPSCs were successfully differentiated and reprogrammed into OSCs. These OSCs may be further clonally expanded and / or cryopreserved as stocks for use in an IVM method or ART application, such as any one of the methods or applications described herein.

[0480] Example 3. A method of follicle stimulation for ovarian release of oocytes and in vitro maturation of oocytes

[0481] This example demonstrates minimal follicle stimulation of a subject with a low ovarian reserve followed by oocyte harvest and in vitro maturation.

[0482] / . Follicle stimulation for ovarian release of oocytes

[0483] A 30-year old female subject receives a blood test that detects an anti-Mullerian hormone (AMH) level of less than or equal to 6 ng / mL (e.g., 1 ng / mL, 2 ng / mL, 3 ng / mL, 4 ng / mL, 5 ng / mL, or 6 ng / mL). Thus, she is determined to have a reduced ovarian reserve. Additional blood tests revealing that her estradiol level is between 20 and 50 pg / mL (e.g., 20-30 pg / mL, 25-35 pg / mL, 30-40 pg / mL, 35-45 pg / mL, or 40-50 pg / mL; e.g., 20 pg / mL, 21 pg / mL, 22 pg / mL, 23 pg / mL, 24 pg / mL, 25 pg / mL, 30 pg / mL, 35 pg / mL, 40 pg / mL, 45 pg / mL, or 50 pg / mL) reaffirms the determination of the reduced ovarian reserve.

[0484] The subject is administered a triggering agent (e.g., 50 mg of clomiphene citrate) to stimulate follicular maturation and oocyte release. Since the subject is taking a hormonal contraceptive, administration of the triggering agent begins on or about day 5 ±1 day (e.g., day 4, day 5, or day 6) after taking her last contraceptive and continues daily for 1 to 4 days (e.g., 1 day, 2 days, 3 days, or 4 days). The subject’s follicle size is monitored by an ultrasound until the average follicle size reaches about 8-10 mm (e.g., 7.5 mm, 8 mm, 8.5 mm, 9mm, 9.5 mm, 10 mm, 10.5 mm, or more), upon which the oocytes (or a group of cells containing an oocyte, e.g., COCs) are retrieved from the subject by an aspiration-based methodology. For example, oocyte retrieval may utilize a transvaginal ultrasound with a needle guide on the probe to suction release follicular contents. Oocyte-containing follicular contents (e.g., follicular aspirates) are after washed with HEPES media (G-MOPS Plus, VITROLIFE®), filtered with a 70-micron cell strainer (FALCON®, Corning), and examined on a dissection microscope. Oocytes (or a group of cells containing an oocyte, e.g., COCs) are transferred to culture dishes containing cell culture media (e.g., IVM, IVF, or LAG media) for about 1 to 3 hours (e.g., 1 hour, 2 hours, or 3 hours) before introducing granulosa cells for co-culture.

[0485] / ' / . In vitro maturation of oocytes

[0486] If present, cultured COCs may be separated from their cumulus cells (and any other non-oocyte cells) in a process referred herein as oocyte denudation. Oocyte denudation is performed on COCs in an IVM well by mechanically disassociating cells by pipetting to remove the cumulus and / or granulosa cells. Additional oocyte denudation may be performed with an enzymatic disassociation (e.g., hyaluronidase treatment). COCs may be stripped with stripper tips and washed in IVM media or MOPS plus media to clean the oocyte for imaging and, if needed, to inactivate hyaluronidase. Stripper tips include 200 micron and / or 400 microns for fine cleaning.

[0487] Next, germinal vesical stage (GVs) and metaphase I stage (Ml) oocytes are co-cultured with about 50,000-100,000 (e.g., 50,000-60,000 cells, 60,000-70,000 cells, 70,000-80,000 cells, 80,000- 90,000 cells, or 90,000-100,000 cells; e.g., 50,000 cells, 55,000 cells, 60,000 cells, 65,000 cells, 70,000 cells, 75,000 cells, 80,000 cells, 85,000 cells, 90,000 cells, 95,000 cells, or 100,000 cells) granulosa cells (e.g., specialized granulosa cells, hiPSC-derived granulosa cells, or steroidogenic granulosa cells, as described herein). Metaphase II stage (Mil) oocytes (e.g., oocytes with a polar body in the perivitelline space) can be properly frozen for storage. Co-culturing of oocytes and granulosa cells is for about 12-120 hours (e.g., 12-24 hours, 12-36 hours, 24-48 hours, 36-60 hours, 54-72 hours, 68-96 hours, 96-120 hours; e.g., 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours, 36 hours, 38 hours, 40 hours, 42 hours, 44 hours, 46 hours, 48 hours, 50 hours, 52 hours, 54 hours, 56 hours, 58 hours, 60 hours, 62 hours, 64 hours, 66 hours, 68 hours, 70 hours, 72 hours, 74 hours, 76 hours, 78 hours, 80 hours, 82 hours, 84 hours, 86 hours, 88 hours, 90 hours, 92 hours, 94 hours, 96 hours, 98 hours, 100 hours, 102 hours, 104 hours, 106 hours, 108 hours,

[0488] 110 hours, 112 hours, 114 hours, 116 hours, 118 hours, or 120 hours).

[0489] Following co-culture, any one or more oocytes are utilized for assisted reproduction technology (ART) procedures. For example, oocytes may be utilized for intracytoplasmic sperm injection (ICSI).

[0490] Example 4. Administration of a follicular triggering agent

[0491] This example demonstrates the administration of a triggering agent to a subject.

[0492] A 30-year old female subject receives a blood test that detects estradiol levels between 20 and 50 pg / mL (e.g., 20-30 pg / mL, 25-35 pg / mL, 30-40 pg / mL, 35-45 pg / mL, or 40-50 pg / mL; e.g., 20 pg / mL, 21 pg / mL, 22 pg / mL, 23 pg / mL, 24 pg / mL, 25 pg / mL, 30 pg / mL, 35 pg / mL, 40 pg / mL, 45 pg / mL, or 50 pg / mL). The subject is administered multiple injections of a triggering agent over 1 to 4 days (e.g., 1 day, 2 days, 3 days, or 4 days) but no more than 5 days. The subject may receive multiple injections over multiple days such that a subject receives five dose injections of one or multiple triggering agents. For example, a subject receives three days of stimulation using 300 IU to 700 IU of rFSH per injection (e.g., 300-500 IU, 400-600 IU, 500-700 IU, 300-350 IU, 350-400 IU, 400-450 IU, 450-500 IU, 500-550 IU, 550- 600 IU, 600-650 IU, 650-700 IU; e.g., 300 IU, 325 IU, 350 IU, 375 IU, 400 IU, 425 IU, 450 IU, 475 IU, 500 IU, 525 IU, 550 IU, 575 IU, 600 IU, 625 IU, 650 IU, 675 IU, or 700 IU) with one or more injections per day. In another example, the subject receives injections of hCG as a triggering agent using 200-700 pg or 2,500-10,000 IU hCG (e.g., 200-500 pg, 300-600 pg, 400-700 pg, 200-300 pg, 300-400 pg, 400-500 pg, 500-600 pg, or 600-700 pg). In yet another example, the subject receives one or more (e.g., 1 , 2, 3, 4, or 5) doses of clomiphene citrate at 50-150 mg (e.g., 50-75 mg, 60-80 mg, 75-100 mg, 90-115 mg, 110-130 mg, 125-150 mg; e.g., 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg) per dose.

[0493] Example 5: Materials and Methods for Examples 6 through 8

[0494] We have developed human ovarian support cells (OSCs) generated from human induced pluripotent stem cells (hiPSCs) that hold the ability to recapitulate dynamic ovarian function in vitro. Here we investigate the potential of these OSCs to improve human oocyte maturation, retrieved from abbreviated gonadotropin stimulated cycles, as a co-culture system applied to IVM. We reveal that OSC- IVM significantly improves maturation rates compared to available IVM systems. Most importantly, we demonstrate OSC-assisted IVM oocytes are capable of robust euploid blastocyst formation, a key marker of their clinical utility. Together, these findings demonstrate a novel approach to IVM with broad applicability to modern IVF practice. Specifically, to determine if IVM of human oocytes can be improved by co-culture with OSCs derived from hiPSCs, oocyte donors were recruited to undergo abbreviated gonadotropin stimulation with or without hCG triggers and COCs were allocated between the OSC-IVM condition and media only IVM controls.

[0495] Oocyte donors between the ages of 19 to 37 years were recruited for donation under informed consent, with an AMH value of greater than 1 ng / mL as inclusion criteria. The OSC-IVM culture condition was composed of 100,000 OSCs in suspension culture with hCG, rFSH, androstenedione, and doxycycline supplementation. IVM controls lacked OSCs and contained the same supplementation or only FSH and hCG.

[0496] Primary endpoints consisted of metaphase II (Mil) formation rate and morphological quality assessment. A limited cohort of oocytes were additionally utilized for fertilization and blastocyst formation with PGT-A analysis. OSC-IVM resulted in a statistically significant improvement in Mil formation rate compared to the media only control. OSC-IVM resulted in a statistically significant improvement in Mil formation rate compared to a commercially available IVM control. Oocyte morphological quality between OSC-IVM and controls did not significantly differ. OSC-IVM improved maturation, fertilization, cleavage, blastocyst formation, high quality blastocyst formation and euploid blastocyst formation compared to the commercially available IVM control.

[0497] As a conclusion, the novel OSC-IVM platform is an effective tool for maturation of human oocytes obtained from abbreviated gonadotropin stimulation cycles, yielding improved blastocyst formation. OSC- IVM shows broad utility for different stimulation regimens, including hCG triggered truncated IVF and untriggered traditional IVM cycles making it a highly useful tool for modern fertility treatment.

[0498] / . Collection of Cumulus Oocyte Complexes (COCs)

[0499] Subject ages, IRB and Informed Consent

[0500] Subjects were enrolled in the study through Ruber Clinic (Madrid, Spain), Spring Fertility Clinic (New York, USA) and Pranor Clinic (Lima, Peru) using informed consent (CNRHA 47 / 428973.9 / 22, IRB # 20225832, Western IRB, and Protocol #GC-MSP-01 respectively). Subject ages ranged between 19 and 37 years of age. Oocytes retrieved from the Ruber and Pranor clinics were utilized for maturation analysis endpoints only, while oocytes retrieved from Spring Fertility were utilized for embryo formation endpoints.

[0501] Stimulation characteristics

[0502] Twenty-five subjects received 3-4 days of stimulation using 300-600 IU of rFSH with an hCG trigger in preparation for immature oocyte aspiration for Experiment 1 , with an AMH value of >1 ng / mL (see below). Twenty-one subjects received three consecutive days of 200 IU of rFSH with an hCG trigger in preparation for immature oocyte aspiration for Experiment 2, with an AMH value of >1 .5ng / mL used as an inclusion cri...

Claims

CLAIMS1 . An ex vivo composition comprising one or more ovarian support cells (OSCs) and one or more diluents or excipients, optionally wherein the composition promotes maturation of one or more oocytes.

2. The composition of claim 1 , wherein the one or more OSCs comprise one or more granulosa cells.

3. The composition of claim 1 or 2, wherein the one or more OSCs express FOXL2, AMHR2, CD82 or any combination thereof.

4. The composition of any one of claims 1 -3, wherein the one or more OSCs express one or more genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB.

5. The composition of any one of claims 1 -4, wherein the one or more OSCs express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46.

6. The composition of any one of claims 1 -5, wherein the one or more OSCs express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3.

7. The composition of any one of claims 1 -6, wherein the one or more OSCs express one or more genes selected from FGF2, TGFB1 , and BMP7.

8. The composition of any one of claims 1 -7, wherein the one or more OSCs express one or more genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4.

9. The composition of any one of claims 1 -8, wherein the one or more OSCs express one or more genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2.

10. The composition of any one of claims 1 -9, wherein the one or more OSCs express one or more genes selected from CDH2 and NOTCH2.11 . The composition of any one of claims 1 -7 and 10, wherein the one or more OSCs do not exhibit significant expression of RARRES2.

12. The composition of any one of claims 1 -11 , wherein the one or more OSCs express one or more genes selected from IGF2BP1 , IGF2BP2, and IGF2BP3.

13. The composition of any one of claims 1 -12, wherein the one or more OSCs express one or more genes selected from TGFB1 and TGFB2.

14. The composition of any one of claims 3-10, 12, and 13, wherein the one or more OSCs express one or more genes selected from STRA6, ERBB4, RARRES2, and EGFR.

15. The composition of any one of claims 1 -14, wherein the one or more OSCs express the gene BMP7.

16. The composition of any one of claims 1 -15, wherein the one or more OSCs express one or more genes selected from VEGFA and VEGFB.

17. The composition of any one of claims 1 -16, wherein the one or more OSCs express the gene PDGFA.

18. The composition of any one of claims 1 -17, wherein the one or more OSCs express NR2F2.

19. The composition of any one of claims 1 -18, wherein the one or more OSCs comprise ovarian stroma cells.

20. The composition of any one of claims 1 -19, wherein the one or more OSCs comprise granulosa cells and ovarian stroma cells.21 . The composition of any one of claims 1 -20, wherein the one or more OSCs comprise more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.

22. The composition of any one of claims 1 -21 , wherein the one or more OSCs are obtained by differentiation of a population of iPSCs, optionally wherein the iPSCs are hiPSCs.

23. The composition of claim 22, wherein the hiPSCs express or overexpress one or more of the following transcription factors:(i) RUNX2;(ii) NR5A1 ;(iii) GATA4;(iv) FOXL2;(v) any combination of two of the transcription factors;(vi) any combination of three of the transcription factors; or(vii) a combination of all four of the transcription factors.

24. The composition of claim 22 or 23, wherein the expression or overexpression of the one or more transcription factors is induced by way of a doxycycline-responsive transcription regulatory element.

25. The composition of any one of claims 22-24, wherein the hiPSCs are contacted with a Wnt / p- catenin pathway activator.

26. The composition of claim 25, wherein the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof.

27. The composition of any one of claims 1 -26, wherein at least one of the one or more OSCs are encapsulated.

28. The composition of claim 27, wherein the one or more OSCs are encapsulated in alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly-D-Lactone, or any mixture thereof, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof.

29. The composition of claim 28, wherein the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is laminin-521 .

30. The system or composition of claim 28 or 29, wherein the one or more OSCs are encapsulated in vitronectin.31 . The composition of any one of claims 1 -30, wherein the one or more OSCs have lower expression, or undetectable expression, of one or more genes associated with pluripotency relative to an iPSC.

32. The composition of claim 31 , wherein the one or more genes associated with pluripotency comprise NANOG.

33. The composition of claim 32, wherein the one or more genes associated with pluripotency comprise POU5F1 .

34. The composition of any one of claims 1 -33, wherein at least some of the OSCs produce one or more growth factors.

35. The composition of claim 34, wherein the one or more growth factors comprise insulin-like growth factor (IGF), stem cell factor (SCF), epidermal growth factor (EGF), leukemia inhibitory factor (LIF), vascular endothelial growth factor (VEGF), bone morphogenetic proteins (BMPs), C-type natriuretic peptide (CNP), or any combination thereof.

36. The composition of claim 34 or 35, wherein at least a portion of the one or more growth factors is secreted.

37. The composition of any one of claims 1 -36, wherein the one or more OSCs produce one or more steroids.

38. The composition of claim 37, wherein the one or more steroids comprise estradiol, progesterone, or a combination thereof.

39. The composition of claim 37 or 38, wherein the one or more steroids are produced in response to hormonal stimulation.

40. The composition of claim 39, wherein the hormonal stimulation comprises FSH, androstenedione treatment, or a combination thereof.41 . The composition of any one of claims 37-40, wherein at least a portion of the one or more steroids is secreted.

42. The composition of any one of claims 1 -41 , wherein the one or more OSCs are cryopreserved.

43. The composition of any one of claims 1 -42, further comprising an in vitro maturation (IVM) media.

44. The composition of claim 43, wherein the IVM media comprises a cell culture media.

45. The composition of claim 43 or 44, wherein the IVM media comprises Medicult-IVM media.

46. The composition of any one of claims 43-45, wherein the IVM media comprises one or more supplements.

47. The composition of claim 46, wherein the one or more supplements comprise:(i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL;(ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;(iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL;(iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;(v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

48. The composition of any one of claims 1 -47, wherein the one or more oocytes are retrieved from a donor subject.

49. The composition of claim 48, wherein the donor subject is from about 19 years old to about 45 years old.

50. The composition of claim 48, wherein the subject is undergoing ovarian stimulation.51 . The composition of claim 50, wherein the ovarian stimulation comprises treatment with gonadotropin releasing hormone (GnRH).

52. The composition of claim 51 , wherein the ovarian stimulation comprises treatment with one or more GnRH analogs.

53. The composition of claim 52, wherein the one or more GnRH analog is a GnRH agonist or antagonist.

54. The composition of any one of claims 50-53, wherein the ovarian stimulation comprises one or more ovulatory triggers.

55. The composition of claim 54, wherein the one or more ovulatory triggers comprise human chorionic gonadotropin (hCG).

56. The composition of claim 54 or 55, wherein the one or more ovulatory trigger comprise a GnRH agonist, optionally wherein the GnRH agonist is leuprolide.

57. The composition of any one of claims 50-56, wherein the ovarian stimulation comprises FSH treatment.

58. The composition of any one of claims 50-56, wherein the ovarian stimulation does not comprise FSH treatment.

59. The composition of claim 57, wherein the FSH treatment comprises 300 international units (IU) to 700 IU of FSH.

60. The composition of claim 59, wherein the FSH treatment comprises 400 IU to 600 IU of FSH.61 . The composition of any one of claims 57, 59, and 60, wherein the FSH treatment comprises 1 , 2, 3, or more injections of FSH, optionally wherein the FSH treatment comprises a plurality of injections, wherein each injection comprises a dose of about 100 IU to about 200 IU of the FSH.

62. The composition of any one of claims 50-61 , wherein the ovarian stimulation further comprises clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more injections, optionally wherein each injection comprises a dose of 50 mg to 150 mg.

63. The composition of claim 50-62, wherein the ovarian stimulation further comprises one or more hCG triggers.

64. The composition of claim 63, wherein the one or more hCG triggers comprises 2,500 IU to 10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose.

65. The composition of any one of claims 1 -64, wherein the one or more oocytes are in cumulus oocyte complexes (COCs).

66. The composition of any one of claims 1 -65, wherein the one or more oocytes comprise one or more denuded immature oocytes.

67. The composition of claim 66, wherein all of the one or more oocytes are denuded immature oocytes.

68. The composition of any one of claims 1 -65, wherein the one or more oocytes are not denuded.

69. The composition of any one of claims 1 -68, wherein the one or more oocytes comprise one or more germinal vesicle (GV)-containing oocytes.

70. The composition of any one of claims 1 -69, wherein the one or more of the oocytes comprise one or more oocytes in metaphase I (Ml).71 . The composition of any one of claims 1 -70, wherein the one or more of the oocytes comprise one or more oocytes in metaphase II (MH).

72. The composition of any one of claims 1 -71 , wherein at least a portion of the one or more oocytes comprise one or more previously vitrified oocytes.

73. The composition of any one of claims 1 -72, wherein at least a portion of the one or more oocytes comprise one or more previously cryopreserved oocytes.

74. The composition of any one of claims 1 -73, wherein the one or more oocytes are co-cultured with the one or more OSCs.

75. The composition of claim 74, wherein prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality.

76. The composition of claim 75, wherein the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

77. The composition of claim 75 or 76, wherein the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs.

78. The composition of any one of claims 75-77, wherein the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes.

79. The composition of any one of claims 74-78, wherein the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

80. The composition of any one of claims 74-79, wherein the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours.81 . The composition of claim 80, wherein the one or more oocytes are co-cultured with the one or more OSCs for about 24 hours to about 28 hours.

82. The composition claim 80 or 81 , wherein the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

83. The composition of any one of claims 74-82, wherein the one or more oocytes are co-cultured in direct contact with the one or more OSCs.

84. The composition of any one of claims 74-83, wherein the one or more oocytes do not directly contact the OSCs.

85. The composition of any one of claims 74-84, wherein the culture system is a suspension culture.

86. The composition of any one of claims 74-84, wherein the culture system is an adherent culture.

87. A method of cultivating oocytes, wherein one or more oocytes are co-cultured with one or more ovarian supporting cells (OSCs).

88. A method of preparing one or more oocytes that have previously been retrieved from a human subject for use in an assisted reproduction technology (ART) procedure, the method comprising coculturing the one or more oocytes with one or more OSCs.

89. A method of producing a mature oocyte for use in an ART procedure, the method comprising coculturing one or more oocytes that have previously been retrieved from a human subject with a population of ovarian support cells that have been differentiated from one or more iPSCs.

90. A method of inducing oocyte maturation in vitro, the method comprising co-culturing one or more oocytes with a population of ovarian support cells that have been differentiated from one or more iPSCs, optionally wherein the co-culturing is conducted for a period of from about 6 hours to about 120 hours.91 . A method of producing a mature oocyte for use in an ART procedure, the method comprising:(a) differentiating one or more iPSCs to produce one or more OSCs;(b) retrieving one or more immature oocytes from a subject; and(c) co-culturing the one or more oocytes with the one or more OSCs, thereby producing one or more mature oocytes.

92. A method of promoting oocyte maturation for a subject undergoing an ART procedure and that has previously been administered one or more follicular triggering agents during a follicular triggering period, the method comprising:(a) retrieving one or more immature oocytes from the subject;(b) co-culturing the one or more oocytes with one or more OSCs that have been differentiated from iPSCs, thereby producing one or more mature oocytes; and(c) isolating the one or more mature oocytes.

93. The method of any one of claims 87-92, wherein prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV- stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Milstage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality.

94. The method of claim 93, wherein the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

95. The method of any one of claims 93 or 94, wherein the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs.

96. The method of claim 95, wherein the one or more co-cultured oocytes have an improved maturation rate compared to oocytes matured in vivo or matured in a cell culture medium without the one or more OSCs.

97. The method any one of claims 93-96, wherein the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes.

98. The method of any one of claims 87-96, wherein the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

99. The method of any one of claims 87-98, wherein the one or more OSCs express FOXL2, AMHR2, CD82 or any combination thereof.

100. The method of any one of claims 87-99, wherein the one or more OSCs express one or more genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB.101 . The method of any one of claims 87-100, wherein the one or more OSCs express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46.

102. The method of any one of claims 87-101 , wherein the one or more OSCs express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3.

103. The method of any one of claims 87-102, wherein the one or more OSCs express one or more genes selected from FGF2, TGFB1 , and BMP7.

104. The method of any one of claims 87-103, wherein the one or more OSCs express one or more of the genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4.

105. The method of any one of claims 87-104, wherein the one or more OSCs express one or more genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2.

106. The method of any one of claims 87-103, wherein the one or more OSCs express one or more genes selected from CDH2 and NOTCH2, with no significant gene expression of RARRES2.

107. The method of any one of claims 87-106, wherein the one or more OSCs express one or more genes selected from IGF2BP1 , IGFBP2, and IGF2BP3.

108. The method of any one of claims 87-107, wherein the one or more OSCs express one or more genes selected from TGFB1 and TGFB2.

109. The method of any one of claims 87-105, 107, and 108, wherein the one or more OSCs express one or more genes selected from STRA6, ERBB4, RARRES2, and EGFR.

110. The method of any one of claims 87-109, wherein the one or more OSCs express gene BMP7.

111. The method of any one of claims 87-110, wherein the one or more OSCs express genes selected from VEGFA and VEGFB.

112. The method of any one of claims 87-111 , wherein the one or more OSCs express gene PDGFA.

113. The method of any one of claims 87-112, wherein the one of more OSCs comprise granulosa cells.

114. The method of any one of claims 87-113, wherein the one or more OSCs express NR2F2.

115. The method of any one of claims 87-114, wherein the one or more OSCs comprise ovarian stroma cells.

116. The method of any one of claims 87-115, wherein the one or more OSCs comprise granulosa cells and ovarian stroma cells.

117. The method of any one of claims 87-116, wherein the one or more OSCs comprise more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.

118. The method of any one of claims 87-117, wherein the one or more OSCs are obtained by differentiation of a population of iPSCs, optionally wherein the population of iPSCs are hiPSCs.

119. The method of claim 118, wherein the hiPSCs express or overexpress the following one or more transcription factors:(i) RUNX2;(ii) NR5A1 ;(iii) GATA4;(iv) FOXL2;(v) any combination of two of the transcription factors;(vi) any combination of three of the transcription factors; or(vii) a combination of all four of the transcription factors.

120. The method of claim 119, wherein the expression or overexpression of the one or more transcription factors is induced by way of a doxycycline-responsive transcription regulatory element.121 . The method of any one of claims 118-120, wherein the hiPSCs are contacted with a Wnt / p- catenin pathway activator.

122. The method claim 121 , wherein the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof.

123. The method of any one of claims 87-122, wherein the one or more OSCs are encapsulated.

124. The method of claim 123, wherein the one or more OSCs are encapsulated in alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly-D-Lactone, or a mixture thereof, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof.

125. The method of claim 124, wherein the one or more OSCs are encapsulated in laminin, optionally wherein the laminin is laminin-521.

126. The method of claim 124 or 125, wherein the one or more OSCs are encapsulated in vitronectin.

127. The method of any one of claims 87-126, wherein the one or more OSCs have low or undetectable expression of one or more genes associated with pluripotency relative to an iPSC.

128. The method of claim 127, wherein the one or more genes associated with pluripotency comprise NANOG.

129. The method of claim 128, wherein the one or more genes associated with pluripotency comprise POU5F1.

130. The method of any one of claims 87-129, wherein the one or more of the OSCs produce one or more growth factors.131 . The method of claim 130, wherein the growth factors comprise IGF, SCF, EGF, LIF, VEGF, BMPs, CNP, or any combination thereof.

132. The method of claim 130 or 131 , wherein at least a portion of the one or more growth factors is secreted.

133. The method of any one of claims 87-132, wherein the one or more OSCs produce one or more steroids.

134. The method of claim 133, wherein the one or more steroids comprise estradiol, progesterone, or a combination thereof.

135. The method of claim 133 or 134, wherein the one or more steroids are produced in response to hormonal stimulation of the OSCs.

136. The method of claim 135, wherein the hormonal stimulation comprises exposure to FSH, androstenedione, or a combination thereof.

137. The method of any one of claims 133-136, wherein at least a portion of the one or more steroids is secreted.

138. The method of any one of claims 87-137, wherein the one or more OSCs were previously cryopreserved.

139. The method of any one of claims 87-138 further comprising culturing the one or more OSCs with the one of more oocytes in an in vitro maturation (IVM) media.

140. The method of claim 139, wherein the IVM media comprises a cell culture media.141 . The method of claim 139 or 140, wherein the IVM media comprises Medicult-IVM media.

142. The method of any one of claims 139-141 , wherein the IVM media comprises one or more supplements.

143. The method of claim 142, wherein the one or more supplements comprise:(i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL;(ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;(iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL;(iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;(v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

144. The method of any one of claims 87-143, wherein the one or more oocytes is retrieved from a donor subject.

145. The method of claim 144, wherein the subject is from about 19 years old to about 45 years old.

146. The method of claim 144, wherein the subject is undergoing ovarian stimulation.

147. The method of claim 146, wherein the ovarian stimulation comprises treatment with gonadotropin releasing hormone (GnRH).

148. The method of claim 147, wherein the ovarian stimulation comprises treatment with one or more GnRH analogs.

149. The method of claim 148, wherein the GnRH analog is a GnRH agonist or antagonist.

150. The method of any one of claims 146-149, wherein the ovarian stimulation comprises one or more ovulatory triggers.151 . The method of claim 150, wherein the one or more ovulatory triggers comprise hCG.

152. The method of claim 150 or 151 , wherein the one or more ovulatory triggers comprise GnRH agonist, optionally wherein the GnRH agonist is leuprolide.

153. The method of any one of claims 146-152, wherein the ovarian stimulation comprises FSH treatment.

154. The method of claim 146-152, wherein the ovarian stimulation does not comprise FSH treatment.

155. The method of claim 153, wherein the FSH treatment comprises 300 IU to 700 IU of FSH.

156. The method of claim 155, wherein the FSH treatment comprises 400 IU to 600 IU of FSH.

157. The method of any one of claims 153, 155, and 156, wherein the FSH treatment comprises 1 , 2,3, or more injections of FSH, optionally wherein the FSH treatment comprises a plurality of injections, wherein each injection comprises a dose of about 100 IU to about 200 IU of the FSH.

158. The method of any one of claims 146-157, wherein the ovarian stimulation comprises clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more doses, optionally wherein each dose is between 50 mg and150 mg.

159. The method of claim 146-158, wherein the ovarian stimulation comprises one or more hCG triggers.

160. The method of claim 159, wherein the one or more hCG triggers comprises 2,500 IU to 10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose.161 . The method of any one of claims 87-160, wherein the one or more oocytes are in cumulus oocyte complexes (COCs).

162. The method of any one of claims 87-161 , wherein the one or more oocytes comprise one or more denuded immature oocytes.

163. The method of claim 162, wherein all of the one or more oocytes are denuded immature oocytes.

164. The method of any one of claims 87-161 , wherein the one or more oocytes are not denuded.

165. The method of any one of claims 87-164, wherein one or more oocytes comprise one or more germinal vesicle (GV)-containing oocytes.

166. The method of any one of claims 87-165, wherein one or more oocytes comprise one or more oocytes in metaphase I (Ml).

167. The method of any one of claims 87-166, wherein one or more oocytes comprise one or more oocytes in metaphase II (Mil).

168. The method of any one of claims 87-167, wherein one or more oocytes comprise one or more previously vitrified oocytes.

169. The method of any one of claims 87-168, wherein one or more oocytes comprise one or more previously cryopreserved oocytes.

170. The method of any one of claims 87-169, wherein the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours.171 . The method of claim 170, wherein the one or more oocytes are cultured with the one or more OSCs for about 24 hours to about 28 hours.

172. The method of claim 170 or 171 , wherein the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

173. The method of any one of claims 87-172, wherein the one or more oocytes are cultured in direct contact with the one or more OSCs.

174. The method of any one of claims 87-173, wherein the one or more oocytes do not directly contact the one or more OSCs.

175. The method of any one of claims 87-174, wherein the co-culture is a suspension co-culture.

176. The method of claim 87-174, wherein the co-culture is an adherent co-culture.

177. A method of promoting differentiation of one or more induced pluripotent stem cells (iPSCs) to one or more ovarian support cells (OSCs), the method comprising:(a) culturing the one or more iPSCs in vitro;(b) inducing, in the one or more iPSCs, expression or overexpression of one or more transcription factors comprising FOXL2, NR5A1 , RUNX2, GATA4, or any combination thereof, thereby producing differentiated cells;(c) determining that the differentiated cells resulting from (b) exhibit a gene expression profile that is similar to that of one or more OSCs; and(d) co-culturing the identified one or more OSCs with one or more oocytes previously retrieved from a subject, thereby maturing the one or more oocytes.

178. A method of producing one or more ovarian support cells (OSCs) from one or more induced pluripotent stem cells (iPSCs), the method comprising:(a) culturing the one or more iPSCs in vitro;(b) inducing, in the one or more iPSCs, expression or overexpression of one or more transcription factors comprising FOXL2, NR5A1 , RUNX2, GATA4, or any combination thereof, thereby producing differentiated cells;(c) determining that the differentiated cells resulting from (b) exhibit a gene expression profile that is similar to that of one or more OSCs; and(d) co-culturing the identified one or more OSCs with one or more oocytes previously retrieved from a subject, thereby maturing the one or more oocytes.

179. A method of preparing a composition comprising one or more ovarian support cells (OSCs), the method comprising:(a) culturing the one or more iPSCs in vitro;(b) inducing, in the one or more iPSCs, expression or overexpression of one or more transcription factors comprising FOXL2, NR5A1 , RUNX2, GATA4, or any combination thereof, thereby producing differentiated cells;(c) determining that the differentiated cells resulting from (b) exhibit a gene expression profile that is similar to that of one or more OSCs; and(d) co-culturing the identified one or more OSCs with one or more oocytes previously retrieved from a subject, thereby maturing the one or more oocytes.

180. The method of any one of claims 177-179, wherein the iPSCs are human iPSCs (hiPSCs).181 . The method of any one of claims 177-180, wherein the iPSCs were previously cryopreserved.

182. The method of any one of claims 177-181 , wherein the co-culturing is performed in in vitro maturation (IVM) media.

183. The method of claim 182, wherein the IVM media comprises a cell culture media.

184. The method of claim 182 or 183, wherein the IVM media comprises Medicult-IVM media.

185. The method of any one of claims 182-184, wherein the IVM media comprises one or more supplements.

186. The method of claim 185, wherein the one or more supplements comprise:(i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL;(ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;(iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL;(iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;(v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

187. The method of any one of claims 177-186, wherein the induction of iPSCs to OSCs occurs for about 1 day to about 10 days, optionally wherein the induction occurs for about 5 days.

188. The method of any one of claims 177-187, wherein the iPSCs are cultured in a media comprising a matrix.

189. The method of claim 188, wherein the matrix comprises alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly-D-Lactone, or a mixture thereof, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof.

190. The method of claim 189, wherein matrix comprises laminin, optionally wherein the laminin is laminin-521 .191 . The method of claim 189 or 190, wherein the matrix comprises vitronectin.

192. The method of any one of claims 177-191 , wherein the iPSCs are reprogrammed using a transposase method to carry one or more inducible transcription factors.

193. The method of any one of claims 177-191 , wherein the iPSCs are transformed via electroporation, liposome-mediated transformation, or viral-mediated gene transfer.

194. The method of any one of claims 177-193, wherein the expression or overexpression of the one or more transcription factors is induced by way of a doxycycline-responsive transcription regulatory element.

195. The method of any one of claims 177-194, wherein the iPSCs are contacted with a Wnt / p- catenin pathway activator.

196. The method claim 195, wherein the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof.

197. The method of any one of claims 177-196, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express FOXL2, AMHR2, CD82, or any combination thereof.

198. The method of any one of claims 177-197, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more of the following genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB.

199. The method of any one of claims 177-198, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46.

200. The method of any one of claims 177-199, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3.201 . The method of any one of claims 177-200, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more genes selected from FGF2, TGFB1 , and BMP7.

202. The method of any one of claims 177-201 , wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more of the genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4.

203. The method of any one of claims 177-202, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more of the genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2.

204. The method of any one of claims 177-201 , wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express genes selected from CDH2 and NOTCH2, optionally with no significant gene expression of RARRES2.

205. The method of any one of claims 177-204, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more of the genes selected from IGF2BP1 , IGF2BP2, and IGF2BP3.

206. The method of any one of claims 177-205, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more of the genes selected from TGFB1 and TGFB2.

207. The method of any one of claims 177-203, 205, and 206, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more of the genes selected from STRA6, ERBB4, RARRES2, and EGFR.

208. The method of any one of claims 177-207, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express the gene BMP7.

209. The method of any one of claims 177-208, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express one or more genes selected from VEGFA and VEGFB.

210. The method of any one of claims 177-209, wherein the gene expression determination of step (c) comprises determining that the one or more differentiated cells express the gene PDGFA.211 . The method of any one of claims 177-210, wherein the one or more OSCs comprise one or more granulosa cells.

212. The method of any one of claims 177-211 , wherein the one or more OSCs express NR2F2.

213. The method of any one of claims 177-212, wherein the one or more OSCs comprise one or more ovarian stroma cells.

214. The method of any one of claims 177-213, wherein the one or more OSCs comprise granulosa cells and ovarian stroma cells.

215. The method of any one of claims 177-214, wherein the one or more OSCs comprise more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.

216. The method of any one of claims 177-215, wherein the one or more OSCs have low or undetectable expression of one or more genes associated with pluripotency relative to an iPSC.

217. The method of claim 216, wherein the one or more genes associated with pluripotency comprise NANOG.

218. The method of claim 217, wherein the one or more genes associated with pluripotency comprise POU5F1.

219. The method of any one of claims 177-218, wherein one or more of the OSCs produce one or more growth factors.

220. The method of claim 219, wherein the growth factors comprise IGF, SCF, EGF, LIF, VEGF, BMPs, CNP, or any combination thereof.221 . The method of claim 219 or 220, wherein at least a portion of the one or more growth factors is secreted.

222. The method of any one of claims 177-221 , wherein the one or more of the OSCs produce one or more steroids.

223. The method of claim 222, wherein the one or more steroids comprise estradiol, progesterone, or a combination thereof.

224. The method of claim 222 or 223, wherein the one or more steroids are produced in the presence of one or more hormones.

225. The method of claim 224, wherein the one or more hormones comprises FSH, androstenedione, or a combination thereof.

226. The method of any one of claims 221 -225, wherein the one or more steroids are secreted.

227. The method of any one of claims 177-226, wherein the one or more oocytes retrieved from the subject are immature oocytes.

228. The method of any one of claims 177-227, wherein the co-culturing the one or more OSCs with one or more oocytes promotes the maturation of the one or more oocytes.

229. The method of any one of claims 177-228, wherein the method further comprises harvesting the one or more oocytes for an assisted reproductive technology procedure.

230. The method of any one of claims 177-229, wherein the subject is undergoing ovarian stimulation prior to the retrieval of one or more oocytes.231 . The method of claim 230, wherein the ovarian stimulation comprises treatment with gonadotropin releasing hormone (GnRH).

232. The method of claim 230 or 231 , wherein the ovarian stimulation comprises treatment with one or more GnRH analogs.

233. The method of claim 232, wherein the one or more GnRH analog is a GnRH agonist or antagonist.

234. The method of any one of claims 230-233, wherein the ovarian stimulation comprises one or more ovulatory triggers.

235. The method of claim 234, wherein the one or more ovulatory triggers comprises hCG.

236. The method of claim 234 or 235, wherein the one or more ovulatory trigger comprises a GnRH agonist, optionally wherein the GnRH agonist is leuprolide.

237. The method of any one of claims 230-236, wherein the ovarian stimulation comprises FSH treatment.

238. The method of any one of claims 230-236, wherein the ovarian stimulation does not comprise FSH treatment.

239. The method of claim 237, wherein the FSH treatment comprises 300 IU to 700 IU of FSH.

240. The method of claim 239, wherein the FSH treatment comprises 400 IU to 600 IU of FSH.241 . The method of any one of claims 237, 239, and 240, wherein the FSH treatment comprises 1 , 2,3, or more injections of FSH, optionally wherein the FSH treatment comprises a plurality of injections, wherein each injection comprises a dose of about 100 IU to about 200 IU of the FSH.

242. The method of any one of claims 230-241 , wherein the ovarian stimulation further comprises clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more doses, optionally wherein each dose is between 50 mg and 150 mg.

243. The method of claim 230-242, wherein the ovarian stimulation further comprises one or more hCG triggers.

244. The composition of claim 243, wherein the one or more hCG triggers comprises 2,500 IU to10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose.

245. The method of any one of claims 177-244, wherein the one or more oocytes are in cumulus oocyte complexes (COCs).

246. The method of any one of claims 177-245, wherein the one or more oocytes comprise one or more denuded immature oocytes.

247. The method of claim 246, wherein all of the one or more oocytes are denuded immature oocytes.

248. The method of any one of claims 177-244, wherein the one or more oocytes are not denuded prior to or following co-culturing.

249. The method of any one of claims 177-248, wherein the one or more oocytes comprise one or more germinal vesicle (GV)-containing oocytes.

250. The method of any one of claims 177-249, wherein the one or more oocytes comprise one or more oocytes in metaphase I (Ml).251 . The method of any one of claims 177-250, wherein the one or more oocytes comprise one or more oocytes in metaphase II (MH).

252. The method of any one of claims 177-251 , wherein at least a portion of the one or more oocytes comprise one or more previously vitrified oocytes.

253. The method of any one of claims 177-252, wherein at least a portion of the one or more oocytes comprises one or more previously cryopreserved oocytes.

254. The method of any one of claims 177-253, wherein prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Mil-stage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality.

255. The method of claim 254, wherein the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprisesoocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

256. The method of claim 254 or 255, wherein the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs.

257. The method of any one of claims 254-256, wherein the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes.

258. The method of any one of claims 177-257, wherein the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

259. The method of any one of claims 177-258, wherein the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours.

260. The method of claim 259, wherein the one or more oocytes are cultured with the one or more OSCs for about 24 hours to about 28 hours.261 . The method of any one of claims 259 or 260, the method further comprising isolating one or more Mil-stage oocytes from the co-culture comprising the one or more oocytes retrieved from the subject with the one or more OSCs.

262. The method of any one of claims 259-261 , wherein the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

263. The method of any one of claims 177-262, wherein the one or more oocytes are cultured in direct contact with the one or more OSCs.

264. The method of claim 177-262, wherein the one or more oocytes do not directly contact the one or more OSCs.

265. The method of any one of claims 177-264, wherein the co-culture is a suspension co-culture.

266. The method of any one of claims 177-264, wherein the co-culture is an adherent co-culture.

267. The method of any one of claims 87-264, further comprising contacting the one or more oocytes with one or more mature sperm cells.

268. The method of claim 267, wherein the one or more oocytes comprise MH stage oocytes.

269. The method of claim 267 or 268, wherein the contacting results in a higher fertilization rate as compared to a fertilization rate resulting from contacting one or more oocytes with one or more mature sperm cells following a method of culturing oocytes in a culture that does not comprise the one or more OSCs.

270. The method of any one of claims 267-269, wherein the contacting results in a fertilization rate is that is about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher, as measured by the proportion of oocytes that are fertilized following the contact with the one or more mature sperm cells.271 . The method of any one of claims 267-270, wherein the contacting results in a higher blastocyst formation rate as compared to a blastocyst formation rate resulting from contacting one or more oocytes with one or more mature sperm cells following a method of culturing oocytes in a culture media that does not comprise the one or more OSCs.

272. The method of any one of claims 267-271 , wherein the contacting results in a greater high quality blastocyst formation rate as compared to a high quality blastocyst formation rate resulting from contacting one or more oocytes with one or more mature sperm cells following a method of culturing oocytes in a culture media that does not comprise the one or more OSCs.

273. The method of any one of claims 267-272, wherein the contacting results in a higher euploid blastocyst formation rate as compared to a euploid blastocyst formation rate resulting from contacting one or more oocytes with one or more mature sperm cells following a method of culturing oocytes in a culture media that does not comprise the one or more OSCs.

274. The method of any one of claims 267-273, wherein the contacting results in a blastocyst formation rate, high quality blastocyst formation rate, and / or euploid blastocyst formation rate that is about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher, as measured by the proportion of oocytes that result in a blastocyst, high quality blastocyst, or euploid blastocyst following the contact with the one or more mature sperm cells.

275. The method of any one of claims 267-274, wherein the contacting results in an embryo that is suitable for implantation into the uterus of a subject.

276. The method of claim 275, wherein the implantation of the embryo into the uterus of the subject results in a pregnancy.

277. The method of claim 276, wherein the subject sustains pregnancy for at least 28 weeks.

278. The method of claim 277, wherein the subject sustains pregnancy for 28 weeks to 42 weeks.

279. The method of any one of claims 276-278, wherein the subject sustains pregnancy, wherein the pregnancy results in a live birth of an infant.

280. A cell culture system comprising one or more ovarian support cells (OSCs), wherein the system promotes maturation of one or more oocytes.281 . The system of claim 280, wherein the one or more OSCs comprise one or more granulosa cells.

282. The system of claim 281 , wherein the one or more OSCs express FOXL2, AMHR2, CD82 or any combination thereof.

283. The system of any one of claims 280-282, wherein the one or more OSCs express one or more genes selected from GJA1 , MDK, BBX, HES4, PBX3, YBX3, BMPR2, CD46, COL4A1 , COL4A2, LAMC1 , ITGAV, and ITGB.

284. The system of any one of claims 280-283, wherein the one or more OSCs express one or more genes selected from BMP4, EFNB2, TGFBR1 , BMPR2, NOTCH2, NOTCH3, and CD46.

285. The system of any one of claims 280-284, wherein the one or more OSCs express one or more genes selected from HES1 , KITLG, NOTCH3, and ID3.

286. The system of any one of claims 280-285, wherein the one or more OSCs express one or more genes selected from FGF2, TGFB1 , and BMP7.

287. The system of any one of claims 280-286, wherein the one or more OSCs express one or more genes selected from FOXO1 , CDH1 , CYP19A1 , RARRES2, NOTCH2, NRG1 , BMPR1 B, EGFR (ERBB1 ), and ERBB4.

288. The system of any one of claims 280-287, wherein the one or more OSCs express one or more genes selected from RARRES2, NOTCH2, NOTCH3, ID3, and BMPR2.

289. The system of any one of claims 280-288, wherein the one or more OSCs express one or more genes selected from CDH2 and NOTCH2.

290. The system of any one of claims 280-286 and 289, wherein the one or more OSCs do not exhibit significant expression of RARRES2.291 . The system of any one of claims 280-290, wherein the one or more OSCs express one or more genes selected from IGF2BP1 , IGF2BP2, and IGF2BP3.

292. The system of any one of claims 280-291 , wherein the one or more OSCs further express one or more genes selected from TGFB1 and TGFB2.

293. The system of any one of claims 280-289, 291 , and 292, wherein the one or more OSCs express one or more genes selected from STRA6, ERBB4, RARRES2, and EGFR.

294. The system of any one of claims 280-293, wherein the one or more OSCs express the gene BMP7.

295. The system of any one of claims 280-294, wherein the one or more OSCs further express one or more genes selected from VEGFA and VEGFB.

296. The system of any one of claims 280-295, wherein the one or more OSCs further express the gene PDGFA.

297. The system of any one of claims 280-296, wherein the one or more OSCs express NR2F2.

298. The system of any one of claims 280-297, wherein the one or more OSCs comprise ovarian stroma cells.

299. The system of any one of claims 290-298, wherein the one or more OSCs comprise granulosa cells and ovarian stroma cells.

300. The system of any one of claims 280-299, wherein the one or more OSCs comprise more than 60% granulosa cells, more than 70% granulosa cells, more than 80% granulosa cells, more than 90% granulosa cells, or more than 95% granulosa cells.301 . The system of any one of claims 280-300, wherein the one or more OSCs are obtained by differentiation of a population of iPSCs, optionally wherein the iPSCs are hiPSCs.

302. The system of claim 301 , wherein the hiPSCs express or overexpress one or more of the following transcription factors:(i) RUNX2;(ii) NR5A1 ;(iii) GATA4;(iv) FOXL2;(v) any combination of two of the transcription factors;(vi) any combination of three of the transcription factors; or(vii) a combination of all four of the transcription factors.

303. The system of claim 301 or 302, wherein the expression or overexpression of the one or more transcription factors is induced by way of a doxycycline-responsive transcription regulatory element.

304. The system of any one of claims 301 -303, wherein the hiPSCs are contacted with a Wnt / p- catenin pathway activator.

305. The system of claim 304, wherein the Wnt / p-catenin pathway activator is a Rho-associated protein kinase (ROCK) inhibitor, a glycogen synthase kinase-3 (GSK3) inhibitor, or a combination thereof.

306. The system of any one of claims 280-305, wherein at least one of the one or more OSCs is encapsulated.

307. The system of claim 306, wherein the OSC(s) are encapsulated in alginate, laminin, collagen, vitronectin, chitosan, hyaluronic acid, Poly-D-Lactone, or any mixture thereof, optionally wherein the laminin is selected from the group consisting of laminin-111 , laminin-211 , laminin-121 , laminin-221 , laminin-332, laminin-311 , laminin-321 , laminin-411 , laminin-421 , laminin-511 , laminin-521 , laminin-213, or a combination thereof.

308. The system of claim 307, wherein the OSC(s) are encapsulated in laminin, optionally wherein the laminin is laminin-521 .

309. The system or system of claim 307 or 308, wherein the OSCs are encapsulated in vitronectin.

310. The system of any one of claims 280-309, wherein the one or more OSCs have lower expression, or undetectable expression, of one or more genes associated with pluripotency relative to an iPSC.311 . The system of claim 310, wherein the one or more genes associated with pluripotency comprises NANOG.

312. The system of claim 311 , wherein the one or more genes associated with pluripotency comprises POU5F1 .

313. The system of any one of claims 280-312, wherein at least some of the OSCs produce one or more growth factors.

314. The system of claim 313, wherein the one or more growth factors comprise insulin-like growth factor (IGF), stem cell factor (SCF), epidermal growth factor (EGF), leukemia inhibitory factor (LIF), vascular endothelial growth factor (VEGF), bone morphogenetic proteins (BMPs), C-type natriuretic peptide (CNP), or any combination thereof.

315. The system of claim 313 or 314, wherein at least a portion of the one or more growth factors are secreted.

316. The system of any one of claims 280-315, wherein one or more of the OSCs produce one or more steroids.

317. The system of claim 316, wherein the one or more steroids comprise estradiol, progesterone, or a combination thereof.

318. The system of claim 316 or 317, wherein the one or more steroids are produced in response to hormonal stimulation.

319. The system of claim 318, wherein the hormonal stimulation comprises FSH, androstenedione treatment, or a combination thereof.

320. The system of any one of claims 316-319, wherein at least a portion of the one or more steroids are secreted.321 . The system of any one of claims 280-320, wherein the one or more OSCs are cryopreserved.

322. The system of any one of claims 280-321 , further comprising an in vitro maturation (IVM) media.

323. The system of claim 322, wherein the IVM media comprises a cell culture media.

324. The system of claim 322 or 323, wherein the IVM media comprises Medicult-IVM media.

325. The system of any one of claims 322-324, wherein the IVM media comprises one or more supplements.

326. The system of claim 325, wherein the one or more supplements comprise:(i) human serum albumin (HSA), optionally at a concentration of about 5 to about 15 mg / mL, further optionally at a concentration of 10 mg / mL;(ii) recombinant follicle stimulating hormone (rFSH), optionally at a concentration of about 70 mIU / mL to about 80 mIU / mL, further optionally at a concentration of 75 mIU / mL;(iii) human chorionic gonadotropin (hCG), optionally at a concentration of about 95 mIU / mL to about 105 mIU / mL, further optionally at a concentration of 100 mIU / mL;(iv) androstenedione, optionally at a concentration of about 495 ng / mL to about 505 ng / mL, further optionally at a concentration of 500 ng / mL;(v) doxycycline, optionally at a concentration of about 0.5 pg / mL to about 1 .5 pg / mL, further optionally at a concentration of 1 pg / mL; or any combination of the one or more supplements.

327. The system of any one of claims 280-326, wherein the one or more oocytes are retrieved from a donor subject.

328. The system of claim 327, wherein the donor subject is from about 19 years old to about 45 years old.

329. The system of claim 327, wherein the subject is undergoing ovarian stimulation.

330. The system of claim 328, wherein the ovarian stimulation comprises treatment with gonadotropin releasing hormone (GnRH).331 . The system of claim 330, wherein the ovarian stimulation comprises treatment with one or more GnRH analogs.

332. The system of claim 331 , wherein the one or more GnRH analog is a GnRH agonist or antagonist.

333. The system of any one of claims 329-332, wherein the ovarian stimulation comprises one or more ovulatory triggers.

334. The system of claim 333, wherein the one or more ovulatory triggers comprises hCG.

335. The system of claim 333 or 334, wherein the one or more ovulatory trigger comprises a GnRH agonist, optionally wherein the GnRH agonist is leuprolide.

336. The system of any one of claims 329-335, wherein the ovarian stimulation comprises FSH treatment.

337. The system of any one of claims 329-335, wherein the ovarian stimulation does not comprise FSH treatment.

338. The system of claim 336, wherein the FSH treatment comprises 300 international units (IU) to 700 IU of FSH.

339. The system of claim 338, wherein the FSH treatment comprises 400 IU to 600 IU of FSH.

340. The system of any one of claims 336, 338, and 339, wherein the FSH treatment comprises 1 , 2, 3, or more injections of FSH, optionally wherein the FSH treatment comprises a plurality of injections, wherein each injection comprises a dose of about 100 IU to about 200 IU of the FSH.341 . The system of any one of claims 328-340, wherein the ovarian stimulation further comprises clomiphene citrate administration, optionally wherein the clomiphene citrate is administered for up to 8 days as one or more doses, optionally wherein each dose is between 50 mg and 150 mg.

342. The system of claim 329-341 , wherein the ovarian stimulation further comprises one or more hCG triggers.

343. The system of claim 342, wherein the one or more hCG triggers comprises 2,500 IU to 10,000 IU of hCG or about 200 pg to about 700 pg of hCG, optionally wherein the hCG is administered to the subject at a dose of about 400 pg to about 600 pg, further optionally wherein the hCG is administered to the subject at a dose of about 500 pg per dose.

344. The system of any one of claims 329-343, wherein the one or more oocytes are in cumulus oocyte complexes (COCs).

345. The system of any one of claims 329-344, wherein the one or more oocytes comprise one or more denuded immature oocytes.

346. The system of claim 345, wherein all of the one or more oocytes are denuded immature oocytes.

347. The system of any one of claims 329-344, wherein the one or more oocytes are not denuded.

348. The system of any one of claims 329-347, wherein one or more oocytes comprise one or more germinal vesicle (GV)-containing oocytes.

349. The system of any one of claims 329-348, wherein one or more of the oocytes comprise one or more oocytes in metaphase I (Ml).

350. The system of any one of claims 329-349, wherein one or more of the oocytes comprise one or more oocytes in metaphase II (MH).351 . The system of any one of claims 329-350, wherein at least a portion of the one or more oocytes comprise one or more previously vitrified oocytes.

352. The system of any one of claims 329-351 , wherein at least a portion of the one or more oocytes comprise one or more previously cryopreserved oocytes.

353. The system of any one of claims 329-352, wherein the one or more oocytes are co-cultured with the one or more OSCs.

354. The system of claim 353, wherein prior to and / or after the co-culturing, the one or more oocytes are evaluated for a parameter selected from the group consisting of total oocyte score, GV-stage to Milstage oocyte maturation rate, GV-stage to Ml-stage oocyte maturation rate, Ml-stage to Mil-stage oocyte maturation rate, average oocyte shape, average oocyte size, average ooplasm quality, average perivitelline space (PVS) quality, average zona pellucida (ZP) quality, and average polar body quality.

355. The system of claim 354, wherein the one or more co-cultured oocytes have morphological quality substantially the same as in vivo matured oocytes, wherein the morphological quality comprises oocyte size, oocyte zona size, oocyte color, oocyte shape, oocyte cytoplasmic granularity, oocyte polar body quality, and oocyte PVS quality.

356. The system of claim 354 or 355, wherein the one or more co-cultured oocytes have an improved maturation rate compared to oocytes in a culture that does not comprise the one or more OSCs.

357. The system of any one of claims 354-356, wherein the one or more co-cultured oocytes have a second meiotic metaphase spindle located substantially in the same position as in vivo matured oocytes.

358. The system of any one of claims 353-357, wherein the one or more co-cultured oocytes have a transcriptomic profile substantially the same as in vivo matured oocytes.

359. The system of any one of claims 353-358, wherein the one or more oocytes are co-cultured with the one or more OSCs for about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, or about 36 hours.

360. The system of claim 359, wherein the one or more oocytes are co-cultured with the one or more OSCs for about 24 hours to about 28 hours.361 . The system claim 359 or 360, wherein the one or more oocytes co-cultured with the one or more OSCs form one or more blastocysts following contact with one or more mature sperm cells.

362. The system of any one of claims 353-361 , wherein the one or more oocytes are co-cultured in direct contact with the one or more OSCs.

363. The system of any one of claims 353-362, wherein the one or more oocytes do not directly contact the OSCs.

364. The system of any one of claims 353-363, wherein the culture system is a suspension culture.

365. The system of any one of claims 353-363, wherein the culture system is an adherent culture.

366. The system of any one of claims 353-365, wherein following the co-culture, the one or more oocytes are contacted with one or more mature sperm cells.

367. The system of claim 366, wherein the one or more oocytes comprise MH stage oocytes.

368. The system of claim 366 or 367, wherein the contact results in a higher fertilization rate as compared to a fertilization rate resulting from contact of one or more oocytes with one or more mature sperm cells following culturing oocytes in a culture that does not comprise the one or more OSCs.

369. The system of claim 368, wherein the contact results in a fertilization rate that is about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher, as measured by the proportion of oocytes that are fertilized following the contact with the one or more mature sperm cells.

370. The system of any one of claims 366-369, wherein the contact results in a higher blastocyst formation rate as compared to a blastocyst formation rate resulting from contact of one or more oocytes with one or more mature sperm cells following culturing oocytes in a culture media that does not comprise the one or more OSCs.371 . The system of any one of claims 366-370, wherein the contact results in a greater high quality blastocyst formation rate as compared to a high quality blastocyst formation rate resulting from contact of one or more oocytes with one or more mature sperm cells following culturing oocytes in a culture media that does not comprise the one or more OSCs.

372. The system of any one of claims 366-371 , wherein the contact results in a higher euploid blastocyst formation rate as compared to a euploid blastocyst formation rate resulting from contact of one or more oocytes with one or more mature sperm cells following culturing oocytes in a culture media that does not comprise the one or more OSCs.

373. The system of any one of claims 366-372, wherein the contact results in a blastocyst formation rate, high quality blastocyst formation rate, and / or euploid blastocyst formation rate that is about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90% or higher, as measured by the proportion of oocytes that result in a blastocyst, high quality blastocyst, or euploid blastocyst following the contact with the one or more mature sperm cells.

374. The system of any one of claims 366-373, wherein the contact results in an embryo that is suitable for implantation into the uterus of a subject.

375. The system of claim 374, wherein the implantation of the embryo into the uterus of the subject results in a pregnancy.

376. The system of claim 375, wherein the subject sustains pregnancy for at least 28 weeks.

377. The system of claim 376, wherein the subject sustains pregnancy for 28 weeks to 42 weeks.

378. The system of any one of claims 375-377, wherein the subject sustains pregnancy, and wherein the pregnancy results in a live birth of an infant.

379. A kit comprising the composition of any one of claims 1 -86 and a package insert, wherein the package insert instructs a user of the kit to co-culture the population of ovarian support cells with one or more oocytes in accordance with the method of any one of claims 87-176 and 267-279.

380. A kit comprising a vial that contains a population of iPSCs and a package insert, wherein the package insert instructs a user of the kit to differentiate the population of iPSCs to one or more ovarian support cells in accordance with the method of any one of claims 177-279.381 . A kit comprising a vial that contains one or more OSCs and a package insert, wherein the package insert instructs a user of the kit to cultivate the cell culture system of any one of claims 280-378.

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