Materials and methods for treating cardiac dysfunction

Abstract

The present disclosure provides methods for improving cardiac dysfunction in a subject by inhibiting 15-hydroxyprostaglandin dehydrogenase (15-PGDH), e.g., by administering a small molecule drug, thereby increasing prostaglandin levels, e.g., prostaglandin E2 (PGE2) levels, in the subject.

Description

PATENT Attorney Docket No.079445-1477342-014210PC Client Ref. No. S23-552 MATERIALS AND METHODS FOR TREATING CARDIAC DYSFUNCTION CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Application No. 63 / 549,914 filed February 5, 2024, the entire contents of which are incorporated herein by reference for all purposes. BACKGROUND

[0002] As individuals live longer and the global demographic landscape undergoes aging, the incidence of cardiovascular disease escalates, posing a substantial health challenge (North, B. J. & Sinclair, D. A., Circ. Res.110, (2012): 1097). In 2019 alone, the toll of cardiovascular- related deaths reached 18.6 million, and projections suggest a continued upward trajectory (Roth, G. A. et al., J. Am. Coll. Cardiol.76, (2020): 2982), placing heart failure as the leading cause of death (Hinderer, S. & Schenke-Layland, K., Adv. Drug Deliv. Rev. 146, (2019): 77). Within the spectrum of cardiomyopathies, Dilated Cardiomyopathy (DCM) emerges as the prevailing and life-threatening subtype. DCM manifests through the gradual expansion of the left ventricle, coupled with a progressive thinning of the cardiac wall, culminating in the onset of cardiac failure. The increasing prevalence of DCM and other cardiomyopathies underscores the critical need for enhanced awareness, preventive measures, and therapeutic interventions to address the growing burden of cardiovascular diseases in an aging population.

[0003] In view of these challenges, there remains a need in the art for effective treatments for preventing or reversing loss of cardiac function in subjects with diseased or damaged cardiac tissues, for example a reduction in cardiac function due to age-related or other diseases and disorders and / or in aged subjects and / or where damage to cardiac tissues occurs to a subject. The present disclosure satisfies this need and provides other advantages as well. BRIEF SUMMARY

[0004] This summary provides a high-level overview of various aspects of the disclosure and introduces some of the concepts that are described and illustrated in the present document and the accompanying figures. The summary is not intended to identify key or essential features ofthe claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. Covered embodiments of the disclosure are defined by the claims, not this summary. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all figures, and each claim. Some of the exemplary embodiments of the present disclosure are discussed below.

[0005] In one aspect, the disclosure provides a method of improving cardiac function in a subject. The method includes reducing 15-hydroxyprostaglandin dehydrogenase (15-PGDH) activity in the heart of the subject. In some instances, the method further includes increasing a level of prostaglandin E2 (PGE2) in the heart of the subject.

[0006] In some embodiments, the reducing of the 15-PGDH activity includes administering to the subject a therapeutically effective amount of a 15-PGDH inhibitor. In some examples, the 15-PGDH inhibitor includes a small molecule drug. In certain examples, the small molecule drug includes 2-(butylsulfinyl)-4-phenyl-6-(thiophen-2-yl)thieno[2,3-b]pyridin-3-amine (SW033291). In some examples, the 15-PGDH inhibitor includes a nucleic acid molecule. In certain examples, the nucleic acid molecule includes a peptide nucleic acid (PNA), an aptamer, an antisense oligonucleotide, a morpholino oligomer, microRNA, siRNA, shRNA, or a combination thereof. In some examples, the 15-PGDH inhibitor includes a gene editing system. In certain examples, the gene editing system includes a CRISPR-Cas system, a zinc-finger nuclease system, a transcription activator-like effector nuclease (TALEN) system, or a combination thereof. In certain examples, the gene editing system includes the CRISPR-Cas system. In certain examples, the CRISPR-Cas system includes a Cas endonuclease coupled to a guide RNA (gRNA) targeting at least a portion of a polynucleotide sequence encoding 15- PGDH. In certain examples, the Cas endonuclease is Cas9 endonuclease. In certain examples, the method includes using the gene editing system to insert a silencer sequence near a polynucleotide sequence encoding 15-PGDH, thereby inhibiting 15-PGDH expression. In certain examples, the administering results in inhibition of transcription factors that negatively regulate the enhancer or promoter of the HPGD gene. In some examples, the 15-PGDH inhibitor includes a polypeptide. In certain examples, the polypeptide includes an antibody, a nanobody, or a combination thereof.

[0007] In some embodiments, reducing 15-PGDH activity includes reducing or blocking expression of 15-PGDH. In some embodiments, reducing 15-PGDH activity includes reducing or blocking enzymatic activity of 15-PGDH.

[0008] In some embodiments, the subject exhibits a cardiomyopathy prior to the reducing of the 15-PGDH activity. In some examples, the cardiomyopathy includes dilated cardiomyopathy (DCM). In some examples, the cardiomyopathy includes Duchenne muscular dystrophy (DMD) cardiomyopathy. In some examples, the cardiomyopathy includes a heritable myopathy caused by a mutation in a gene. In certain examples, the gene includes TTN (titin),TNNT2 (troponin T), TPM1 ( -tropomyosin), RBM20 (encoding RNA binding motif protein20), BAG3 (BLC2-associated athanogene 3), DES (desmin), FLNC (filamin-C), LMNA (lamin A / C), MYH7 (myosin heavy chain 7), PLN (phospholamban), SCN5A (sodium channel -subunit), TNNC1 (troponin C), DSP (desmoplakin), ACTC1 (cardiac -actin), ACTN2 ( -actinin-2), JPH2 (Junctophilin 2), NEXN (nexilin), TNNI3 (troponin I), VCL (vinculin), or a combination thereof. In some examples the cardiomyopathy is a consequence of ischemic heart disease, hypertension, an endocrine disorder (e.g., thyroid disease and / or diabetes), myocarditis, an autoimmune disease, or a combination thereof.

[0009] In some embodiments, the subject exhibits age-related reduced cardiac metabolism prior to the reducing of the 15-PGDH activity. In some examples, the age-related reduced cardiac metabolism includes an altered cardiac glucose uptake relative to a cardiac glucose uptake exhibited by the subject at a younger age.

[0010] In some embodiments, the subject has one or more biomarkers of aging. In some examples, the one or more biomarkers of aging include an increase in 15-PGDH levels relative to a young individual, a decrease in PGE2 levels relative to a young individual, an increase in a PGE2 metabolite relative to a young individual, an increase or a greater accumulation of senescent cells relative to a young individual, an increase in expression of one or more atrogenes relative to a young individual, a decrease in mitochondria biogenesis and / or function relative to a young individual, an increase in transforming growth factor pathway signaling relative to a young individual, or a combination thereof.

[0011] In some embodiments, the method further includes increasing a left ventricular fractional shortening (FS) cardiac output of the subject. In some embodiments, the method further includes increasing a left ventricular ejection fraction (LVEF) of the subject. In some embodiments, the method further includes increasing endogenous expression of a mitochondrial gene by the subject. In some embodiments, the method further includes restoring cardiac glucose uptake by the subject to within 25% of a cardiac glucose uptake exhibited by the subject at a younger age. In some embodiments, the subject is a human.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG.1 shows a schematic representation of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) inhibition by SW033291.

[0013] FIG.2A shows an experimental scheme of the 15-PGDH inhibition treatment. TM54 mice (a transgenic model expressing a mutant tropomyosin found in humans with DCM) were treated for four weeks with daily intraperitoneal injections of 15-PGDH inhibitory drug: SW033291 (SW) or vehicle (veh). Wild-type (WT) mice vehicle-treated were used as control.

[0014] FIG. 2B shows representative echocardiographic images of m-mode from WT vehicle-treated, TM54 vehicle-treated, and TM54 SW-treated mice at the end of the treatment. Within each image, the left vertical line indicates the LVEDD (left ventricular end-diastolic diameter), and the right vertical line indicates the LVESD (left ventricular end-systolic diameter). The white numbers indicate the fractional shortening calculated for each image.

[0015] FIG. 2C shows fractional shortening (FS) of the hearts across the treatment. p < 0.05, p < 0.01, and p < 0.001.

[0016] FIG.2D shows values for left ventricle ejection fraction (LVEF) calculated at the end of the treatment. p < 0.05, p < 0.01, and p < 0.001.

[0017] FIG.3A shows an experimental scheme testing a 15-PGDH inhibition treatment. For four weeks, mdx / mTRG2mice were treated with daily intraperitoneal injections of the 15- PGDH inhibitory drug SW033291 (SW) or vehicle (veh). WT vehicle-treated mice were used as control.

[0018] FIG. 3B shows representative echocardiographic images of m-mode from WT vehicle-treated, mdx / mTRG2vehicle-treated, and mdx / mTRG2SW-treated mice at the end of the treatment.

[0019] FIG. 3C shows fractional shortening (FS) data for hearts across the treatment in the experiment of FIGS.3A-B. p < 0.05, and p < 0.01.

[0020] FIG. 3D shows left ventricle ejection fraction (LVEF) data calculated at the end of the treatment in the experiment of FIGS.3A-C. p < 0.05, and p < 0.01.

[0021] FIG.4A presents a heatmap showing mitochondria gene expression in young vehicle- treated mice (YV), aged vehicle-treated mice (AV), and aged SW033291-treated mice (ASW).

[0022] FIG. 4B shows glucose uptake data from evaluation of the hearts of young vehicle- treated mice (YV), aged vehicle-treated mice (AV), and aged SW033291-treated mice (ASW). p < 0.05, p < 0.01, and p < 0.001. DETAILED DESCRIPTION I. INTRODUCTION

[0023] Prostaglandin E2 (PGE2) is an eicosanoid derived from arachidonic acid with multifaceted physiological functions such as vasodilation and anti-inflammatory effects, which have been reported to have beneficial effects on the heart (Fu, J. et al., J. Mol. Cell. Cardiol. 172, (2022): 63; Bärnthaler, T. et al., J. Allergy Clin. Immunol. 145, (2020): 818; Thomas, P. E., Peters-Golden, M., White, E. S., Thannickal, V. J. & Moore, B. B., Am. J. of Physiol. Lung Cell. Mol. Physiol. (2007): 293; Smith, J. N. P. et al., Sci. Rep.10, (2020): 11657). As illustrated in FIG. 1A, degradation of PGE2 is catalyzed by the enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Prior studies have underscored the significance of inhibiting 15- PGDH as a pioneering approach to elevating PGE2 levels within a physiologically relevant range (Palla, A. R. et al., Science 371, (2021): eabc8059). Additionally, elevated expression of the 15-PGDH gene or its transcript has been identified as a marker of aging in many tissues, including the heart (Palla, A. R. et al., Science 371, (2021): eabc8059). Moreover, tests of the systemic inhibition of 15-PGDH over a one-month period resulted in a substantial increase in PGE2 levels within the skeletal muscle, leading to a remarkable increase in muscle mass and function. Treated mice also exhibited improved endurance on a treadmill (Palla, A. R. et al., Science 371, (2021): eabc8059), leaving open the possibility that the effect of the inhibitory drug could be pleiotropic and extend to tissues beyond skeletal muscle.

[0024] The inventors of the methods and materials provided in this disclosure have now determined that 15-PGDH is upregulated in the context of cardiac disease and in the aging heart, with this upregulation correlating with a decrease in PGE2 levels. In particular, 15- PGDH was found to be upregulated in dilated and hypertrophic cardiomyopathies of genetic etiology. Data showed that reduction in PGE2 signaling, due to increased 15-PGDH activity and consequent PGE2 degradation, leads to altered pathways that ultimately have a deleterious effect on cardiac function. Together, these findings indicate a 15-PGDH / PGE2 regulatory axis having an impact on cardiac dysfunction.

[0025] Based on these insights, the inventors have surprisingly demonstrated that 15-PGDH inhibition, for example via local or systemic administration of a small molecule, gene therapy,a blocking antibody, a nanobody, siRNA, or other means described herein, can be effectively used for the treatment of cardiovascular disease of genetic and non-genetic etiology, including, for example, dilated cardiomyopathy (DCM), cardiac hypertrophy, and aging-associated dysfunction. The provided 15-PGDH inhibition techniques can therefore improve cardiac function in subjects who have, for example, DCM due to heritable mutations as in Duchenne muscular dystrophy (DMD), and can also result in an overall metabolic improvement in the aged heart. These disclosed strategies are thus applicable to the treatment of cardiomyopathy in several cardiac diseases.

[0026] The approaches described herein offer several advantages and improvements over existing methodologies. Currently available drugs for the treatment of cardiac dysfunction only aim to slow down loss in cardiac function (heart.org / en / health-topics / heart-failure / treatment- options-for-heart-failure / medications-used-to-treat-heart-failure). For example, angiotensin- converting enzyme (ACE) inhibitors are administered to treat hypertension. In another example, beta-blockers, are administered to lower heart rate. The provided methods rely instead on 15-PGDH inhibition, presenting a new approach that targets heart tissue to improve cardiac function. Advantageously, 15-PGDH inhibition effects can be locally targeted to specific sites where 15-PGDH is high, such as diseased cardiac tissues. As another benefit, 15-PGDH inhibition carries fewer adverse effects than direct PGE2 administration since 15-PGDH inhibition causes increases in PGE2 at physiological levels. Additionally, while PGE2 has a short half-life and therefore its delivery and activity are limited to the site of injection, 15- PGDH inhibition can be achieved by using longer half-life molecules and gene therapy which can advantageously provide systemic benefits when desired. II. DEFINITIONS

[0027] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this disclosure belongs. In addition, any method or material similar or equivalent to a method or material described herein can be used in the practice of the present disclosure. For purposes of the present disclosure, the following terms are defined.

[0028] As used herein, the singular forms “a,” “an,” and “the” include both singular and plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a payload sequence” optionally includes a combination of two or more payload sequences, and the like.

[0029] As used herein, the term “and / or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”).

[0030] As used herein, the terms “including,” “comprising,” “having,” “containing,” and variations thereof, are inclusive and open-ended and do not exclude additional, unrecited elements or method steps beyond those explicitly recited. As used herein, the phrase “consisting of” is closed and excludes any element, step, or ingredient not explicitly specified. As used herein, the phrase “consisting essentially of” limits the scope of the described feature to the specified materials or steps and those that do not materially affect the basic and novel characteristics of the disclosed feature.

[0031] The term “optional” or “optionally” means that the subsequent described event, circumstance or substituent may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0032] The terms “first,” “second,” “third,” and the like when used herein with reference to elements or properties, are simply to more clearly distinguish or identify multiple elements or properties, and are not intended to indicate an order or other serial or numerical limitation, or to require that each of the multiple elements or properties are present.

[0033] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure.

[0034] Certain ranges are presented herein with numerical values being preceded by the term “about.” The term “about” is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes, such as variations of + / - 10% or less, + / - 1-5% or less, + / - 1% or less, and + / - 0.1% or less from the specified value. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrecited number may be a numberwhich, in the context in which it is presented, provides the substantial equivalent of the specifically recited number.

[0035] As used herein, the terms “age-related condition,” “age-related disease,” or the like refer to any disease, condition, or disorder that shows or potentially shows any signs or features associated with increasing age or passage of time in the heart of a subject, including, e.g., loss or decrease of tissue and / or organ function, loss or decrease of tissue and / or organ health, loss or decrease of one or more physiological activities of the tissue and / or organ, decreased protein synthesis in cells of the tissue and / or organ, increased protein degradation in cells of the tissue and / or organ, decreased survival or viability of the tissue and / or organ, decreased proliferation of cells within the tissue and / or organ, shortened telomeres in cells of the tissue and / or organ, mitochondrial dysfunction in cells of the tissue and / or organ, increased presence of senescent cells in the tissue and / or organ, increased levels of 15-PGDH levels and / or activity in the tissue and / or organ, decreased levels of PGE2 in the tissue and / or organ, etc. The condition or disease can be a result of natural aging processes due to the passage of time, of other factors such as lifestyle factors or disease, e.g., infectious disease, or of genetic conditions that cause premature aging.

[0036] As used herein, the terms “prostaglandin E2,” “PGE2,” and “dinoprostone” are used interchangeably and refer to prostaglandin that can be synthesized from arachidonic acid via cyclooxygenase (COX) enzymes and terminal prostaglandin E synthases (PGES). PGE2 plays a role in a number of biological functions including vasodilation, inflammation, and modulation of sleep / wake cycles. Structural and functional information about PGE2 can be found, e.g., in the entry for “Dinoprostone” of PubChem: pubchem.ncbi.nlm.nih.gov / compound / Dinoprostone, the contents of which are herein incorporated by reference in their entirety.

[0037] “15-PGDH” (15-hydroxyprostaglandin dehydrogenase) is an enzyme involved in the inactivation of a number of active prostaglandins, e.g., by catalyzing oxidation of PGE2 to 15- keto-prostaglandin E2 (15-keto-PGE2). The human enzyme is encoded by the HPGD gene (Gene ID: 3248). The enzyme is a member of the short-chain nonmetalloenzyme alcohol dehydrogenase protein family. Multiple isoforms of the enzyme exist, e.g., in humans, any of which can be targeted using the present methods. For example, any of human isoforms 1-6 (e.g., GenBank Accession Nos. NP_000851.2, NP_001139288.1, NP_001243236.1, NP_001243234.1, NP_001243235.1, NP_001350503.1, NP_001243230.1) can be targeted, ascan any isoform with 50%, 60%, 70%, 80%, 85%, 90%, 95%, 99%, or higher identity to the amino acid sequences of any of GenBank Accession Nos. NP_000851.2, NP_001139288.1, NP_001243236.1, NP_001243234.1, NP_001243235.1, NP_001350503.1, NP_001243230.1, or of any other 15-PGDH enzyme.

[0038] A “prostaglandin-E synthase” (PGES) is an enzyme (isomerase) that catalyzes the conversion of prostaglandin-H (PGH) into PGE2. Cytosolic PGES (cPGES) is a cytosolic protein that is constitutively expressed in a wide variety of cells and tissues and is associated with heat shock protein 90 (Hsp90). Membrane-associated PGES (mPGES), the expression of which is stimulus-inducible and is downregulated by anti-inflammatory glucocorticoids, is a perinuclear protein belonging to the microsomal glutathione S-transferase (GST) family. These two PGESs display distinct functional coupling with upstream COXs in cells; cPGES is predominantly coupled with the constitutive COX-1, whereas mPGES is preferentially linked with the inducible COX-2. Several cytosolic GSTs also have the capacity to convert PGH2 to PGE2 in vitro. The human enzyme is encoded by, for example, the PTGES (HGNC: 9599; NCBI Entrez Gene: 9536; Ensembl: ENSG00000148334; OMIM: 605172; UniProtKB / Swiss- Prot: O14684) and PTGES2 genes (HGNC: 17822; NCBI Entrez Gene: 80142; Ensembl: ENSG00000148334; OMIM: 608152; UniProtKB / Swiss-Prot: Q9H7Z7). Any of the human PGES enzymes can be targeted, as can any isoform with 50%, 60%, 70%, 80%, 85%, 90%, 95%, 99%, or higher identity to the amino acid sequences of any of the prostaglandin-E synthase enzymes, including prostaglandin-E synthase 1 and prostaglandin-E synthase 2.

[0039] “Cyclooxeygenases” or “COX” enzymes are also involved in the synthesis of prostaglandins, including PGE2, by oxygenation of arachidonic acid, DGLA or EPA and terminal prostaglandin synthases. Also known as prostaglandin-endoperoxide synthase (PTGS), cyclooxygenase is an enzyme (family of isozymes, EC 1.14.99.1) that is responsible for formation of prostanoids, including thromboxane and prostaglandins, from arachidonic acid. A member of the animal-type heme peroxidase family, it is also known as prostaglandin G / H synthase. The specific reaction catalyzed is the conversion from arachidonic acid to prostaglandin H2, via a short-living prostaglandin G2 intermediate.

[0040] As used herein, the terms “15-PGDH inhibitor and / or PGE2 activator,” “15-PGDH agent,” “15-PGDH compound,” “PGE2 agent,” and “PGE2 compound” refer to any one or more agents that are capable, independently or in combination, of inhibiting, reducing, decreasing, attenuating, abolishing, eliminating, slowing, and / or counteracting in any way anyaspect of the expression, stability, and / or activity of 15-PGDH. The terms can refer to any molecule, either naturally occurring or synthetic, e.g., peptide, protein, oligopeptide (e.g., from about 5 to about 25 amino acids in length, e.g., about 5, about 10, about 15, about 20, or about 25 amino acids in length), small molecule (e.g., an organic molecule having a molecular weight of less than about 2500 daltons, e.g., less than about 2000, less than about 1000, or less than about 500 daltons), antibody, nanobody, polysaccharide, lipid, fatty acid, inhibitory RNA (e.g., siRNA, shRNA, microRNA), modified RNA, polynucleotide, oligonucleotide, e.g., peptide nucleic acid (PNA), an aptamer, antisense oligonucleotide, morpholino oligomer, affimer, drug compound, or other compound. In some embodiments, the inhibitory RNA (e.g., siRNA, shRNA, microRNA), modified RNA, polynucleotide, morpholino oligomer, affimer, aptamer or oligonucleotide may be at least about 5 nucleotides, 10 nucleotides, 15 nucleotides, 20 nucleotides, 25 nucleotides, 30 nucleotides, 35 nucleotides, 40 nucleotides, 45 nucleotides, or 50 nucleotides in length.

[0041] As used herein, the terms “expression” and “expressed” refer to the production of a transcriptional and / or translational product, e.g., of a nucleic acid sequence encoding a protein (e.g., 15-PGDH) or signaling molecule (e.g. PGE2). In some embodiments, the terms refer to the production of a transcriptional and / or translational product encoded by a gene (e.g., the human HPGD gene) or a portion thereof. The level of expression of a DNA molecule in a cell may be assessed on the basis of either the amount of corresponding mRNA that is present within the cell or the amount of protein encoded by that DNA produced by the cell. In some embodiments, the term refers to the synthesis of a signaling product, e.g., PGE2 synthesis from arachidonic acid through expression of prostaglandin synthases (e.g., prostaglandin-E synthases, including prostaglandin-E synthase-1 and prostaglandin-E synthase 2, and COX1 and COX2 enzymes).

[0042] As used herein, the terms “nucleic acid” and “polynucleotide” refer to deoxyribonucleic acids (DNA) or ribonucleic acids (RNA) and polymers thereof in either single- or double-stranded form. Unless specifically limited, the term encompasses nucleic acids containing known analogs of natural nucleotides that have similar binding properties as the reference nucleic acid and are metabolized in a manner similar to naturally occurring nucleotides. Unless otherwise indicated, a particular nucleic acid sequence also implicitly encompasses conservatively modified variants thereof (e.g., degenerate codon substitutions), alleles, orthologs, SNPs, and complementary sequences as well as the sequence explicitly indicated. In particular embodiments, modified RNA molecules are used, e.g., mRNA withcertain chemical modifications to allow increased stability and / or translation when introduced into cells, as described in more detail below. It will be appreciated that any of the RNAs used in the present methods, including nucleic acid inhibitors such as siRNA or shRNA, can be used with chemical modifications to enhance, e.g., stability and / or potency, e.g., as described in Dar et al. (2016) Scientific Reports 6: article no. 20031 (2016), and as presented in the database accessible at crdd.osdd.net / servers / sirnamod / .

[0043] As used herein, the term “expression cassette” refers to a nucleic acid construct, generated recombinantly or synthetically, with a series of specified nucleic acid elements that permit transcription of a particular polynucleotide sequence in a host cell. An expression cassette may be part of a plasmid, viral genome, or nucleic acid fragment. Typically, an expression cassette includes a polynucleotide to be transcribed, operably linked to a promoter. The promoter can be a heterologous promoter. In the context of promoters operably linked to a polynucleotide, a “heterologous promoter” refers to a promoter that would not be so operably linked to the same polynucleotide as found in a product of nature (e.g., in a wild-type organism).

[0044] As used herein, the terms “polypeptide,” “peptide,” and “protein” are used interchangeably to refer to a polymer of amino acid residues. All three terms apply to amino acid polymers in which one or more amino acid residue is an artificial chemical mimetic of a corresponding naturally occurring amino acid, as well as to naturally occurring amino acid polymers and non-naturally occurring amino acid polymers. As used herein, the terms encompass amino acid chains of any length, including full-length proteins, wherein the amino acid residues are linked by covalent peptide bonds.

[0045] As used herein, the term “antibody” refers to a polypeptide encoded by an immunoglobulin gene or functional fragments thereof that specifically binds and recognizes an antigen. The recognized immunoglobulin genes include the kappa, lambda, alpha, gamma, delta, epsilon, and mu constant region genes, as well as the myriad immunoglobulin variable region genes. Light chains are classified as either kappa or lambda. Heavy chains are classified as gamma, mu, alpha, delta, or epsilon, which in turn define the immunoglobulin classes, IgG, IgM, IgA, IgD and IgE, respectively. The term includes antibody fragments having the same antigen specificity, and fusion products thereof.

[0046] An exemplary immunoglobulin (antibody) structural unit includes a tetramer. Each tetramer is composed of two identical pairs of polypeptide chains, each pair having one “light”chain (about 25 kDa) and one “heavy” chain (about 50-70 kDa). The N-terminus of each chain defines a variable region of about 100 to 110 or more amino acids primarily responsible for antigen recognition. Thus, the terms “variable heavy chain,” “VH”, or “VH” refer to the variable region of an immunoglobulin heavy chain, including an Fv, scFv, dsFv or Fab; while the terms “variable light chain,” “VL”, or “VL” refer to the variable region of an immunoglobulin light chain, including of an Fv, scFv, dsFv or Fab. Equivalent molecules include antigen binding proteins having the desired antigen specificity, derived, for example, by modifying an antibody fragment or by selection from a phage display library.

[0047] The terms “antigen-binding portion” and “antigen-binding fragment” are used interchangeably herein and refer to one or more fragments of an antibody that retains the ability to specifically bind to an antigen (e.g., a 15-PGDH protein or prostaglandin-E synthases). Examples of antibody-binding fragments include, but are not limited to, a Fab fragment (amonovalent fragment consisting of the VL, VH, CL, and CH1 domains), F(ab )2 fragment (abivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region), a single chain Fv (scFv), a disulfide-linked Fv (dsFv), complementarity determining regions (CDRs), VL (light chain variable region), VH (heavy chain variable region), nanobodies, and any combination of those or any other functional portion of an immunoglobulin peptide capable of binding to target antigen (see, e.g., Fundamental Immunology (Paul ed., 4th ed.2001).

[0048] As used herein, the phrase “specifically binds” refers to a molecule (e.g., a 15-PGDH inhibitor and / or PGE2 activator) that binds to a target with greater affinity, avidity, more readily, and / or with greater duration to that target in a sample than it binds to a non-target compound. In some embodiments, a molecule that specifically binds a target (e.g., 15-PGDH, PGE2 or prostaglandin-E synthases) binds to the target with at least 2-fold greater affinity than non-target compounds, e.g., at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold, at least 9-fold, at least 10-fold, at least 20-fold, at least 25-fold, at least 50-fold or greater affinity. For example, in some embodiments, a molecule that specifically binds to 15-PGDH or PGE2 typically binds to 15-PGDH or PGE2 with at least a 2-fold greater affinity than to a non-15-PGDH or PGE2 target.

[0049] The term “derivative,” as used herein in the context of a compound, includes but is not limited to, amide, ether, ester, amino, carboxyl, acetyl, and / or alcohol derivatives of a given compound.

[0050] As used herein, the terms “identical” or percent “identity,” in the context of describing two or more polynucleotide or amino acid sequences, refer to two or more sequences or specified subsequences that are the same. Two sequences that are “substantially identical” have at least about 60% identity, preferably at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or about 100% identity, when compared and aligned for maximum correspondence over a comparison window, or designated region as measured using a sequence comparison algorithm or by manual alignment and visual inspection where a specific region is not designated. With regard to polynucleotide sequences, this definition also refers to the complement of a test sequence. With regard to amino acid sequences, in some cases, the identity exists over a region that is at least about 50 amino acids or nucleotides in length, or more preferably over a region that is 75-100 amino acids or nucleotides in length.

[0051] For sequence comparison, typically one sequence acts as a reference sequence, to which test sequences are compared. When using a sequence comparison algorithm, test and reference sequences are entered into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. Default program parameters can be used, or alternative parameters can be designated. The sequence comparison algorithm then calculates the percent sequence identities for the test sequences relative to the reference sequence, based on the program parameters. For sequence comparison of nucleic acids and proteins, the BLAST 2.0 algorithm and the default parameters are used.

[0052] As used herein, the terms “pharmaceutically acceptable excipient” and “pharmaceutically acceptable carrier” refer to a substance that aids the administration of an active agent to and absorption by a subject and may be included in the compositions of the present disclosure without causing a significant adverse toxicological effect on the subject. Non-limiting examples of pharmaceutically acceptable excipients and carriers include water, NaCl, normal saline solutions, normal sucrose, normal glucose, binders, fillers, disintegrants, lubricants, coatings, and the like. One of skill in the art will recognize that other pharmaceutically acceptable excipients and carriers are useful in the present disclosure.

[0053] As used herein, the term “subject” refers to a vertebrate, and preferably to a mammal. Mammalian subjects for which the provided composition is suitable include, but are not limitedto, mice, rats, simians, humans, farm animals, sport animals, and pets. In some embodiments, the subject is human. In some embodiments, the subject is male. In some embodiments, the subject is female. In some embodiments, the subject is an adult. In some embodiments, the subject is an adolescent. In some embodiments, the subject is a child. In some embodiments, the subject is above 10 years of age, e.g., above 20 years of age, above 30 years of age, above 40 years of age, above 50 years of age, above 60 years of age, above 70 years of age, or above 80 years of age. In some embodiments, the subject is less than 80 years of age, e.g., less than 70 years of age, less than 60 years of age, less than 50 years of age, less than 40 years of age, less than 30 years of age, less than 20 years of age, or less than 10 years of age.

[0054] As used herein, the term “administering” refers to oral administration, administration as a suppository, topical contact, parenteral, intravenous, intraperitoneal, intramuscular, intralesional, intranasal, subcutaneous, intrathecal, intraventricular, intracerebral, intracerebroventricular, intraparenchymal, retinal, subretinal, or intravitreal administration, or the implantation of a slow release device e.g., a mini osmotic pump, to the subject.

[0055] As used herein, the term “therapeutically effective amount” refers to an amount or dose of a compound, composition, or formulation that produces therapeutic effects for which it is administered. The exact amount or dose will depend on the purpose of the treatment, and will be ascertainable by one skilled in the art using known techniques (see, e.g., Lieberman, Pharmaceutical Dosage Forms (vols. 13, 1992); Lloyd, The Art, Science and Technology of Pharmaceutical Compounding (1999); Pickar, Dosage Calculations (1999); and Remington: The Science and Practice of Pharmacy, 20th Edition, 2003, Gennaro, Ed., Lippincott, Williams & Wilkins).

[0056] As used herein, the terms “treat” and “treatment” refer to both therapeutic treatment and prophylactic or preventive measures, wherein the object is to eliminate, slow down, or prevent disease progression or manifestation as indicated by undesired physiological change or disorder. For purpose of this disclosure, the benefits of treatment include, but are not limited to, partial or complete alleviation of symptoms, delay of disease progression, amelioration of disease, improvement in patient outcomes (e.g., increase in patient survival), stabilization of a disease parameter (e.g., cardiac function). These benefits may detectable or undetectable.III. METHODS OF IMPROVING CARDIAC FUNCTION

[0057] Provided herein are methods of improving the cardiac function of a subject, e.g., a subject in need of improved cardiac function. In some examples, the subject has a reduced cardiac function prior to performance of the provided method. In certain examples, the subject is a patient having a reduced cardiac function. Accordingly, in some examples, the provided methods are suitable for treating a subject that has a disease or disorder characterized by a recued cardiac function. Such diseases include, for example, cardiovascular disease of genetic and non-genetic etiology. Examples of cardiovascular disease that can be treated with the provided methods include dilated cardiomyopathy, cardiac hypertrophy, and aging-associated dysfunction. In certain examples, the provided methods improve cardiac function by using one or more small molecules, e.g., any of the drugs and inhibitors described by the present disclosure.

[0058] Generally, the provided methods include reducing the activity of 15- hydroxyprostaglandin dehydrogenase (15-PGDH) activity in the heart of the subject. In some embodiments, the provided methods additionally or alternatively increase PGE levels in the heart of a subject. Because PGE2 has a short half-life, its delivery and its activity are local to the site of administration in a subject. In contrast, 15-PGDH inhibition can be achieved by longer half-life molecules and gene therapy which can provide systemic benefits. Thus, in preferred embodiments, the method of treatment includes reducing 15-PGDH activity in the heart of a subject.

[0059] In particular examples, the inhibition of 15-PGDH in the subject leads to an increase in PGE2, e.g., an elevation, increase, or restoration of PGE2 levels, in the heart of the subject, and a decrease in PGE2 metabolites such as 15-keto-PGE2 and / or 13,14-dihydro-15-keto- PGE2 (PGEM). In some examples, the inhibition also leads to increased signaling through PGE2 receptors, e.g., EP1, EP2, EP3, and / or EP4 (also known as Ptger1, Ptger2, Ptger3, Ptger4) in the heart.

[0060] In some examples, the 15-PGDH inhibition decreases the activity, stability, or expression of 15-PGDH by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, or more relative to a control level, e.g., in the absence of the inhibition, in vivo or in vitro.

[0061] In some examples, levels of PGE2 present within the heart of the subject are increased (e.g., after treatment with a 15-PGDH inhibitor and / or PGE2 activator, e.g., according to methods provided herein) relative to levels present in the heart prior to performance of the provided method (e.g., prior to treatment with the 15-PGDH inhibitor and / or PGE2 activator). PGE2 levels in the heart may be increased (e.g., by any method disclosed herein) by at least about 5% (e.g., by at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or greater) relative to levels present in the heart prior to performance of the method (e.g., prior to treatment with a 15-PGDH inhibitor and / or PGE2 activator). In certain examples, levels of PGE2 present within the heart are increased (e.g., after treatment with a 15-PGDH inhibitor and / or PGE2 activator, e.g., according to methods provided herein) to a level substantially similar to a level present in a young heart. PGE2 levels in heart may be increased (e.g., by any method disclosed herein) to a level within about 50% or less (e.g., within about 40%, within about 35%, within about 30%, within about 25%, within about 20%, within about 15%, within about 10%, within about 5%, or within about 1%) of a level present in a young heart.

[0062] In some examples, levels of PGE2 metabolites present within the heart of the subject are decreased (e.g., after treatment with a 15-PGDH inhibitor, e.g., according to methods provided herein) relative to levels present in the heart prior to performance of the provided method (e.g., prior to treatment with the 15-PGDH inhibitor). PGE2 metabolite levels in the heart may be decreased (e.g., by any method disclosed herein) by at least about 5% (e.g., by at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or greater) relative to levels present in the heart prior to performance of the method (e.g., prior to treatment with a 15-PGDH inhibitor). In certain examples, levels of PGE2 metabolites present within the heart are decreased (e.g., after treatment with a 15-PGDH inhibitor, e.g., according to methods provided herein) to a level substantially similar to a level present in a young heart. PGE2 metabolite levels in the heart may be decreased (e.g., by any method disclosed herein) to a level within about 50% or less (e.g., within about 40%, within about 35%, within about 30%, within about 25%, within about 20%, within about 15%, within about 10%, within about 5%, or within about 1%) of a level present in a young heart. The PGE2 metabolite can include, for example, 15-keto PGE2, 13,14-dihydro-15-keto PGE2, or both. The PGE2 metabolite can be 15-keto PGE2, 13,14-dihydro-15-keto PGE2, or both.

[0063] In some embodiments, PGE2 is present in a subject at physiological levels when the subject is treated with a 15-PGDH inhibitor. In some embodiments, PGE2 levels in a subject treated with a 15-PGDH inhibitor increases by at least 2-fold when compared to an untreated patient. In some embodiments, 15-PGDH inhibition effects are localized to specific sites where 15-PGDH levels are high, e.g., diseased cardiac tissues. In some embodiments, 15-PGDH inhibition in a patient causes fewer adverse effects than direct administration of PGE2 to a subject. A. IMPROVED CARDIAC FUNCTIONS

[0064] In some examples, a function of the heart of the subject is enhanced (e.g., after treatment with a 15-PGDH inhibitor and / or PGE2 activator, e.g., according to methods provided herein) relative to the heart prior to performance of the provided method (e.g., prior to treatment with the 15-PGDH inhibitor and / or PGE2 activator). A function of the heart may be enhanced (e.g., by any method disclosed herein) by at least about 5% (e.g., by at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or greater) relative to levels present in the heart prior to performance of the method (e.g., prior to performance with the 15-PGDH inhibitor and / or PGE2 activator). In certain examples, a function of the heart is enhanced (e.g., after treatment with a 15-PGDH inhibitor and / or PGE2 activator, e.g., according to methods provided herein) to a level substantially similar to a level present in a young heart. A function of the heart may be enhanced (e.g., by any method disclosed herein) to a level within about 50% or less (e.g., within about 40%, within about 35%, within about 30%, within about 25%, within about 20%, within about 15%, within about 10%, within about 5%, or within about 1%) of a level present in a young heart.

[0065] In some examples, following performance of the provided method (e.g., after administration of a 15-PGDH inhibitor and / or PGE2 activator), the cardiac muscle of the subject exhibits increased or enhanced cardiac muscle tissue functions (e.g., as compared to the cardiac muscle prior to treatment with the 15-PGDH inhibitor and / or PGE2 activator) as determined by: echocardiogram, transesophageal echocardiography (TEE), electrocardiogram (ECG or EKG), magnetic resonance imaging (MRI), CT scan, exercise cardiac stress test, pharmacologic stress test, tilt test, ambulatory rhythm monitoring tests, or coronary angiogram. In some examples, after performance of the method, the cardiac muscle is capable of functioning at substantially similar to levels found in young cardiac muscle. In some examples, after performance of the method, the cardiac muscle is capable of improved functioning suchas pumping oxygenated blood to the other body parts; pumping hormones and other vital substances to different parts of the body; receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation; or maintaining blood pressure at levels that are substantially similar to levels found in young cardiac muscle.

[0066] In particular examples, the herein-described benefits of 15-PGDH inhibitor and / or PGE2 activator administration in the heart, e.g., improved cardiac function, occur independently of any regeneration of the heart in the subject. In other words, while there may be regeneration of the heart in the subject, e.g., if the heart has been injured or damaged, the herein-described effects do not require the regeneration and would occur even without the regeneration. In particular examples, heart is not injured or damaged and has not or does not undergo regeneration.

[0067] In some embodiments, the provided method increases left ventricular fractional shortening (LVFS) of the subject. Additionally or alternatively, the method can increase left ventricular ejection fraction (LVEF) of the subject. Additionally or alternatively, the method can increase endogenous expression of a mitochondrial gene by the subject. Additionally or alternatively, the method can increases cardiac glucose uptake by the subject. Other nonlimiting examples of cardiac functions that can be improved with the provided method include, for example, increased protein synthesis, increased cell proliferation, increased cell survival, decreased protein degradation, or any combination thereof. Still further nonlimiting examples of cardiac functions improved with the provided method include, for example, muscle size, muscle fiber length, contraction rate, relaxation rate, maximum contraction velocity, isotonic strength, isometric force, muscle power, muscle fatigue, muscle quality based on maximal muscle force and power production relative to muscle size, and electrical signal transmission. B. SUBJECTS

[0068] In some embodiments, the 15-PGDH inhibitor is administered to a subject who previously exhibited cardiomyopathy, e.g., dilated cardiomyopathy (DCM) or Duchenne muscular dystrophy (DMD) cardiomyopathy. In some embodiments, the subject exhibits a heritable cardiomyopathy caused by a mutation in a gene. For example, the cardiomyopathy could be the result of one or more mutations in one or more genes such as TTN (titin), TNNT2(troponin T), TPM1 ( -tropomyosin), RBM20 (encoding RNA binding motif protein 20),BAG3 (BLC2-associated athanogene 3), DES (desmin), FLNC (filamin-C), LMNA (laminA / C), MYH7 (myosin heavy chain 7), PLN (phospholamban), SCN5A (sodium channel -subunit), TNNC1 (troponin C), DSP (desmoplakin), ACTC1 (cardiac -actin), ACTN2 ( -actinin-2), JPH2 (Junctophilin 2), NEXN (nexilin), TNNI3 (troponin I), or VCL (vinculin). Additionally or alternatively, the cardiomyopathy can be a consequence of ischemic heart disease, hypertension, an endocrine disorder (e.g., thyroid disease and / or diabetes), myocarditis, an autoimmune disease, or a combination thereof. In some embodiments, the subject exhibits age-related reduced cardiac metabolism prior to the reducing of the 15-PGDH activity. In some embodiments, the age-related reduced cardiac metabolism includes a reduced glucose uptake.

[0069] In some examples of the provided methods, the subject expresses one or more biomarkers of aging prior to the performance of the method. Examples of biomarkers of aging include, without limitation, an increase in 15-PGDH levels (e.g., relative to a level present in a young heart), a decrease in PGE2 levels (e.g., relative to a level present in a young heart) an increase in a PGE2 metabolite (e.g., relative to a level present in a young heart), an increase or a greater accumulation of senescent cells (e.g., relative to a level present in a young heart), an increase in expression of one or more atrogenes (e.g., Atrogin1 (MAFbx1), Fbxo30 (MuSA), and Trim63 (MuRF1)) (e.g., relative to a level present in a young heart, a decrease in mitochondria biogenesis and / or function (e.g., relative to a level present in a young heart), an increase in transforming growth factor pathway signaling (e.g., an increase in expression of one or more genes involved in a transforming growth factor signaling pathway, e.g., one or more of Activin receptor, Myostatin, a SMAD protein, and a bone morphogenetic protein) (e.g., relative to a level present in a young heart), and combinations thereof. In some cases, a biomarker of aging includes increased levels or activity of 15-PGDH, In some cases, a biomarker of aging includes decreased levels of PGE2. In some cases, a biomarker of aging includes increased levels of a PGE2 metabolite (e.g., 15-keto PGE2 and 13,14-dihydro-15-keto PGE2). In some cases, the presence of a biomarker of aging indicates that the subject is likely to benefit from a treatment according to any method disclosed herein. A young heart may include a heart of a subject under the age of 30 (e.g., 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 years of age).

[0070] The subject of the provided method can be any subject, e.g., a human or other mammal. In some examples, the subject is a subject with an age-related condition or a subject at risk of having an age-related condition. In some embodiments, the subject is a human. In some embodiments, the subject is an adult. In some embodiments, the subject is a child (e.g.,a child with a genetic disorder that causes premature aging, e.g., progeria). In some embodiments, the subject is female (e.g., an adult female). In some embodiments, the subject is male (e.g., an adult male).

[0071] In some examples, the subject is human, and the provided method further includes a step in which the human is selected for the method, e.g., for treatment with a 15-PGDH inhibitor and / or PGE2 activator based on a diagnosis of an age-related condition or disease, or on the potential for or risk of developing an age-related condition or disease, or based on the age of the individual, or based on the presence of one or more biomarkers of aging as described herein. In some such examples, the human is selected based on his or her age. For example, a human can be selected based on an age that is over 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 years old or older, or any age in which the human has or potentially has an age-related condition or disease or has one or more biomarkers of aging as described herein. In some embodiments, the human is selected based on a potential for an age-related condition or disease, based on the presence or potential presence of an environmental, lifestyle, or medical factor linked to premature aging of the heart, such as smoking, drinking, diet, lack of physical activity, insufficient sleep, drug use, exposure to UV rays, exposure to extreme temperatures, stress, excess weight, or health-related factors such as infections, mental illness, cancer, diabetes, etc. In some embodiments, the subject has an age-related condition caused by premature aging of one or more tissues, e.g., a genetic disorder such as Osteogenesis imperfecta, Bloom syndrome, Cockayne Syndrome, Hutchinson-Gilford Progeria Syndrome, Mandibuloacral Dysplasia, Progeria, Progeroid Syndrome, Rothmund-Thomson Syndrome, Seip Syndrome, Werner Syndrome, Down Syndrome, Acrogeria, Rothmund-Thomson syndrome, an immunodeficiency of these tissues that lead to premature aging syndromes, such as Ataxia telangiectasia, or an infectious disease of these tissues that lead to premature aging syndromes, such as human immunodeficiency virus (HIV).

[0072] In some embodiments, the subject is determined to have a need for improved cardiac function (e.g., a subject in need of treatment and / or a subject having an age-related condition or disease) using any method of assessing any measure of the function, performance, health, strength, endurance, physiological activity, or any other property of the heart of the subject, e.g., a performance-based, imaging-based, physiological, molecular, cellular, or functional assay. For example, a heart can be assessed using any method of assessing heart function or health, such as angiograms, electrocardiograms, treadmill test, echocardiogram, etc. In some embodiments, the subject is selected for treatment based on a detection of elevated levels of15-PGDH transcript or prostaglandin-E synthases transcript, protein, or enzymatic activity in the heart, or on a detection of decreased COX1 and / or COX2 enzymes or levels of PGE2 in the heart.

[0073] In some examples, the provided methods include an additional step subsequent to the reducing 15-PGDH activity in the heart of the subject, where the additional step includes assessing the health, function, performance, or any other property of heart of the subject, or where the additional step includes assessing the level of 15-PGDH (e.g., of 15-PGDH protein or transcript) and / or PGE2 in the heart of the subject. In some such examples, the health, function, performance, 15-PGDH level, PGE2 level, or other property of the heart is detected or examined and compared to the health, function, performance, 15-PGDH level, PGE2 level, or other property of the heart prior to the reduction of the heart 15-PGDH activity, wherein a determination that the health, function, or performance of the heart has improved, that the 15- PGDH level has decreased, and / or that the PGE2 level has increased in the heart subsequent to the 15-PGDH activity reduction as compared to the value obtained prior to the 15-PGDH activity reduction indicates that the 15-PGDH activity reduction has had a beneficial effect on the heart of the subject.

[0074] In some examples, subjects are identified for treatment based on a diagnosis of an age-related condition, disorder, or disease; based on a determination of the presence of or potential for age-related loss of cardiac function; based on a subject’s age, e.g., an age associated with an age-related condition or disease; or based on a detection of any of the herein- described features or indicators of cardiac dysfunction, e.g., of elevated levels of PGE2 metabolites such as 15-keto-PGE2, or PGEM, of decreased levels of PGE2, of decreased protein synthesis, of decreased mitochondrial activity, of decreased signaling through the EP1, EP2, EP3, EP4, DP1, and / or DP2 receptors, of elevated expression of genes associated with the senescence phenotype such as p16 (Ink4a) or p21 (Cdkn1a), of shortened telomere length in cells of the tissue, of elevated numbers of senescent cells in a heart of a subject, or of elevated levels or activity of 15-PGDH.

[0075] In some examples, the subject is a pet or a farm animal such as a porcine, bovine, or ovine animal, poultry, or fish, and the methods are used, e.g., to enhance cardiac function or health in an aging animal or in an animal having an injured, damaged, or diseased heart. In some examples, a vector or expression cassette comprising a nucleic acid inhibitor of 15-PGDH or enhancer of PGE2 synthesis (e.g., prostaglandin-E synthases), e.g., an shRNA, is introducedinto the animal such that the nucleic acid inhibitor or enhancer is expressed in the cells of the animal, e.g., the cells of the heart. In some embodiments, a vector or expression cassette comprising a polynucleotide encoding a polypeptide inhibitor of 15-PGDH or enhancer of PGE2 synthesis (e.g., prostaglandin-E synthases), e.g., an antibody or peptide, is introduced into the animal such that the polypeptide inhibitor or enhancer is expressed in the cells of the animal, e.g., the cells of the heart. In some examples, gene therapy is used, e.g., such that all or part of an endogenous 15-PGDH encoding gene is replaced with a form of the gene that is less active, less stable, or less highly expressed in cardiac cells of the animal. In some examples, gene therapy is used, e.g., such that all or part of an endogenous PGE2 synthase gene is replaced with a form of the gene that is more active, more stable, or more highly expressed in cardiac cells of the animal. In some examples, modified RNA, e.g., a chemically modified RNA inhibitor such as shRNA or a chemically modified mRNA encoding a polypeptide 15-PGDH inhibitor and / or PGE2 activator is introduced into the animal such that the RNA inhibitor or activator, or the expressed inhibitor or activator, is present in cells of the animal. C. ASSESSMENTS OF 15-PGDH AND PGE2 LEVELS

[0076] The present disclosure also provides methods of measuring 15-PGDH and PGE2 levels in the heart of a subject. Such methods are useful, e.g., for the use of 15-PGDH and PGE2 as a biomarker of aging or an aging heart, e.g., wherein an elevated level of 15-PDGH levels or activity or a depressed level of PGE2 levels or activity, e.g., an increase or decrease of about 5%, an increase or decrease of about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 100% or more relative to a control level in a subject without an age-related condition is indicative of aging or a loss or decrease of function in the heart. In such methods, 15-PGDH or PGE2 can be assessed in any of a number of ways, e.g., by detecting levels of a transcript encoding a 15-PGDH protein or prostaglandin synthases (e.g., prostaglandin-E synthases, includingprostaglandin-E synthase 1 and prostaglandin-E synthase 2 and COX1 and COX2 enzymes), by detecting levels of a 15- PGDH polypeptide or PGE2, or by detecting 15-PGDH or prostaglandin-E synthases enzymatic activity.

[0077] Any of a number of methods can be used to assess the level of 15-PGDH and / or PGE2 in a heart, e.g., when using 15-PGDH or PGE2 as a biomarker or when assessing the efficacy of an inhibitor of 15-PGDH or an activator of PGE2. For example, the level of 15-PGDH and PGE2 can be assessed by examining the transcription of a gene encoding 15-PGDH (e.g., the HPGD gene) or enzyme involved in the synthesis of PGE2 (e.g., prostaglandin-E synthases),by examining the levels of 15-PGDH protein or PGE2 in the heart, or by measuring the 15- PGDH enzyme activity or PGE2 activity in the heart.

[0078] In some examples, the provided methods involve the measurement of 15-PGDH enzyme activity, e.g., using standard methods such as incubating a candidate compound in the presence of 15-PGDH enzyme, NAD(+), and PGE2 in an appropriate reaction buffer, and monitoring the generation of NADH (see, e.g., Zhang et al., (2015) Science 348: 1224), or by using any of a number of available kits such as the fluorometric PicoProbe 15-PGDH Activity Assay Kit (BioVision), or by using any of the methods and / or indices described in, e.g., European Patent Application Publication No. EP2838533.

[0079] In some examples, the provided methods involve the detection of 15-PGDH-encoding or PGE2 enzyme (e.g., prostaglandin-E synthases) polynucleotide (e.g., mRNA) expression, which can be analyzed using routine techniques such as RT-PCR, Real-Time RT-PCR, semi- quantitative RT-PCR, quantitative polymerase chain reaction (qPCR), quantitative RT-PCR (qRT-PCR), multiplexed branched DNA (bDNA) assay, microarray hybridization, or sequence analysis (e.g., RNA sequencing (“RNA-Seq”)). Methods of quantifying polynucleotide expression are described, e.g., in Fassbinder-Orth, Integrative and Comparative Biology, 2014, 54:396-406; Thellin et al., Biotechnology Advances, 2009, 27:323-333; and Zheng et al., Clinical Chemistry, 2006, 52:7 (doi: 10 / 1373 / clinchem.2005.065078). In some embodiments, real-time or quantitative PCR or RT-PCR is used to measure the level of a polynucleotide (e.g., mRNA) in a biological sample. See, e.g., Nolan et al., Nat. Protoc, 2006, 1:1559-1582; Wong et al., BioTechniques, 2005, 39:75-75. Quantitative PCR and RT-PCR assays for measuring gene expression are also commercially available (e.g., TaqMan® Gene Expression Assays, ThermoFisher Scientific).

[0080] In some examples, the provided methods involve the detection of 15-PGDH protein or PGE2 synthesis or stability, e.g., using routine techniques such as immunoassays, two- dimensional gel electrophoresis, and quantitative mass spectrometry that are known to those skilled in the art. Protein quantification techniques are generally described in “Strategies for Protein Quantitation,” Principles of Proteomics, 2nd Edition, R. Twyman, ed., Garland Science, 2013. In some embodiments, protein (e.g., 15-PGDH) or signaling molecule (e.g., PGE2) expression or stability is detected by immunoassay, such as but not limited to enzyme immunoassays (EIA) such as enzyme multiplied immunoassay technique (EMIT), enzyme- linked immunosorbent assay (ELISA), IgM antibody capture ELISA (MAC ELISA), andmicroparticle enzyme immunoassay (MEIA); capillary electrophoresis immunoassays (CEIA); radioimmunoassays (RIA); immunoradiometric assays (IRMA); immunofluorescence (IF); fluorescence polarization immunoassays (FPIA); and chemiluminescence assays (CL). If desired, such immunoassays can be automated. Immunoassays can also be used in conjunction with laser induced fluorescence (see, e.g., Schmalzing et al., Electrophoresis, 18:2184-93 (1997); Bao, J. Chromatogr. B. Biomed. Sci., 699:463-80 (1997)). D. 15-PGDH INHIBITORS

[0081] In some embodiments, a 15-PGDH inhibitor is used to reduce 15-PGDH activity, thereby improving the cardiac function of the subject. In some embodiments, the provided method includes administering a therapeutically effective amount of a 15-PGDH inhibitor to a subject. In some embodiments, a 15-PGDH inhibitor and / or PGE2 activator is administered to a subject, e.g., a patient, to improve cardiac function, in the subject, where the 15-PGDH inhibitor and / or PGE2 activator can include any one or more agents that are capable, independently or in combination, of inhibiting, reducing, decreasing, attenuating, abolishing, eliminating, slowing, and / or counteracting in any way any aspect of the expression, stability, and / or activity of 15-PGDH. In some embodiments, a 15-PGDH inhibitor is administered to a patient via local or systemic administration of a small molecule drug, gene therapy, blocking antibody, nanobody, siRNA, or any combination thereof.

[0082] A 15-PGDH inhibitor and / or PGE2 activator can, for example, reduce or increase any aspect of the expression, e.g., transcription, RNA processing, RNA stability, and / or translation of a gene encoding 15-PGDH, e.g., the human HPGD gene, or PGE2, e.g., prostaglandin-E synthases, for example, PTGES1 (prostaglandin E synthase 1) or PTGES2 (prostaglandin E synthase 2) gene, or associated upstream enzymes, including COX1 and COX2 (cyclooxygenase 1 and 2, respectively) by, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more as compared to a control, e.g., in the absence of the inhibitor, in vitro or in vivo. A 15-PGDH inhibitor and / or PGE2 activator can, for example, inhibit or enhance transcription factors that promote or enhance expression of the gene encoding 15-PGDH, e.g., the human HPGD gene, or PGE2, e.g. prostaglandin synthase genes, for example, PTGES1 (prostaglandin E synthase 1), PTGES2 (prostaglandin E synthase 2) gene, or associated upstream enzymes, including COX1 and COX2 (cyclooxygenase 1 and 2, respectively) by, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more as compared to a control, e.g., in the absence of the inhibitor, in vitro or in vivo. Similarly, a 15-PGDH inhibitor and / or PGE2 activator can, for example, reduce or increase the activity, e.g., enzymatic activity, of a 15-PGDH enzyme or PGE2 synthase by, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more as compared to a control, e.g., in the absence of the inhibitor, in vitro or in vivo. Further, a 15- PGDH inhibitor and / or PGE2 activator can, for example, reduce or increase the stability of a 15-PGDH enzyme or PGE2 synthase by, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more as compared to a control, e.g., in the absence of the inhibitor, in vitro or in vivo.

[0083] In some embodiments, the 15-PGDH inhibitor and / or PGE2 activator is considered effective if the level of expression of a 15-PGDH-encoding polynucleotide is decreased by at least about 5%, at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% or more as compared to the reference value, e.g., the value in the absence of the inhibitor, in vitro or in vivo. In some embodiments, a 15-PGDH inhibitor and / or PGE2 activator is considered effective if the level of expression of a 15-PGDH-encoding polynucleotide is decreased by at least about 1.5-fold, at least about 2-fold, at least about 3- fold, at least about 4-fold, at least about 5-fold, at least about 6-fold, at least about 7-fold, at least about 8-fold, at least about 9-fold, at least about 10-fold, or more as compared to the reference value. 1. Small Molecules

[0084] In some embodiments, the 15-PGDH inhibitor includes or consists of a small molecule drug, or a prodrug thereof, wherein the prodrug can be metabolized into a pharmacologically active form of the small molecule drug, for example, at the site of administration or when exposed to cardiac muscle cells. In some embodiments, the 15-PGDH inhibitor small molecule drug includes 2-(butylsulfinyl)-4-phenyl-6-(thiophen-2-yl)thieno[2,3- b]pyridin-3-amine (SW033291). In some embodiments, the 15-PGDH inhibitor is SW033291.

[0085] In particular embodiments, 15-PGDH is inhibited by the co-administration of a small molecule inhibitor, for example, as a combination therapy. Any small molecule inhibitor can be used that reduces, e.g., by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about90%, or more, the expression, stability, or activity of 15-PGDH relative to a control, e.g., the expression, stability, or activity in the absence of the 15-PGDH inhibitor and / or PGE2 activator. In particular embodiments, small molecule inhibitors may be used that can reduce the enzymatic activity of 15-PGDH in vitro or in vivo. Non-limiting examples of small molecule compounds that can be used in the present methods include the small molecules disclosed in European Patent Application Publication No. EP 2838533, the entire disclosure of which is herein incorporated by reference. Small molecules can include, inter alia, the small molecules disclosed in Table 2 of EP 2838533, i.e., SW033291, SW033291 isomer B, SW033291 isomer A, SW033292, 413423, 980653, 405320, SW208078, SW208079, SW033290, SW208080, SW208081, SW206976, SW206977, SW206978, SW206979, SW206980, SW206992, SW208064, SW208065, SW208066, SW208067, SW208068, SW208069, SW208070, as well as combinations, derivatives, isomers, or tautomers thereof.

[0086] In some embodiments, the 15-PGDH inhibitor is a thiazolidinedione derivative (e.g., benzylidenethiazolidine-2,4-dione derivative) such as (5-(4-(2-(thiophen-2- yl)ethoxy)benzylidene)thiazolidine-2,4-dione), 5-(3-chloro-4- phenylethoxybenzylidene)thiazolidine-2,4-dione, 5-(4-(2- cyclohexylethoxy)benzylidene)thiazolidine-2,4-dione, 5-(3-chloro-4-(2- cyclohexylethoxy)benzyl)thiazolidine-2,4-dione, (Z)-N-benzyl-4-((2,4-dioxothiazolidin-5- ylidene)methyl)benzamide, or any of the compounds disclosed in Choi et al. (2013) Bioorganic & Medicinal Chemistry 21:4477-4484; Wu et al. (2010) Bioorg. Med. Chem. 18(2010) 1428- 1433; Wu et al. (2011) J. Med. Chem. 54:5260-5264; or Yu et al. (2019) Biotechnology and Bioprocess Engineering 24:464-475, the entire disclosures of which are herein incorporated by reference. In some embodiments, the 15-PGDH inhibitor is a COX inhibitor or chemopreventive agent such as ciglitazone (CID: 2750), or any of the compounds disclosed in Cho et al. (2002) Prostaglandins, Leukotrienes and Essential Fatty Acids 67(6):461-465, the entire disclosure of which is herein incorporated by reference.

[0087] In some embodiments, the 15-PGDH inhibitor is a compound containing a benzimidazole group, such as (1-(4-methoxyphenyl)-1H-benzo[d]imidazol-5-yl)(piperidin-1- yl)methanone (CID: 3474778), or a compound containing a triazole group, such as 3-(2,5- dimethyl-1-(p-tolyl)-1H-pyrrol-3-yl)-6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepine (CID: 71307851), or any of the compounds disclosed in Duveau et al. (2015) (“Discovery of two small molecule inhibitors, ML387 and ML388, of human NAD+-dependent 15- hydroxyprostaglandin dehydrogenase,” published in Probe Reports from the NIH MolecularLibraries Program [Internet]), the entire disclosure of which is herein incorporated by reference. In some embodiments, the 15-PGDH inhibitor is 1-(3-methylphenyl)-1H- benzimidazol-5-yl)(piperidin-1-yl)methanone (CID: 4249877) or any of the compounds disclosed in Niesen et al. (2010) PLoS ONE 5(11):e13719, the entire disclosure of which is herein incorporated by reference. In some embodiments, the 15-PGDH inhibitor and / or PGE2 activator is 2-((6-bromo-4H-imidazo[4,5-b]pyridin-2-ylthio)methyl)benzonitrile (CID: 3245059), piperidin-1-yl(1-m-tolyl-1H-benzo[d]imidazol-5-yl)methanone (CID: 3243760), or 3-(2,5-dimethyl-1-phenyl-1H-pyrrol-3-yl)-6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3- a]azepine (CID: 2331284), or any of the compounds disclosed in Jadhav et al. (2011) (“Potent and selective inhibitors of NAD+-dependent 15-hydroxyprostaglandin dehydrogenase (HPGD),” published in Probe Reports from the NIH Molecular Libraries Program [Internet]), the entire disclosure of which is herein incorporated by reference.

[0088] In some embodiments, the 15-PGDH inhibitor is TD88 or any of the compounds disclosed in Seo et al. (2015) Prostaglandins, Leukotrienes and Essential Fatty Acids 97:35- 41, or Shao et al. (2015) Genes & Diseases 2(4):295-298, the entire disclosures of which are herein incorporated by reference. In some embodiments, the 15-PGDH inhibitor and / or PGE2 activator is EEAH (Ethanol extract of Artocarpus heterophyllus) or any of the compounds disclosed in Karna (2017) Pharmacogn Mag. 2017 Jan; 13(Suppl 1): S122–S126, the entire disclosure of which is herein incorporated by reference. 2. Nucleic Acid Molecules

[0089] In some embodiments, the 15-PGDH inhibitor includes or consists of an inhibitory nucleic acid, e.g., antisense DNA or RNA, morpholino oligomer, small interfering RNA (siRNA), microRNA (miRNA), or short hairpin RNA (shRNA). In some embodiments, the inhibitory RNA targets a sequence that is identical or substantially identical (e.g., at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% identical) to a target sequence in a 15-PGDH polynucleotide (e.g., a portion comprising at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 100 contiguous nucleotides, e.g., from 20-500, 20-250, 20-100, 50-500, or 50-250 contiguous nucleotides of a 15-PGDH-encoding polynucleotide sequence (e.g., the human HPGD gene, Gene ID: 3248, including of any of its transcript variants, e.g., as set forth in GenBankAccession Nos. NM_000860.6, NM_001145816.2, NM_001256301.1, NM_001256305.1, NM_001256306.1, NM_001256307.1, or NM_001363574.1).

[0090] In some embodiments, the provided methods include treating a subject, e.g., a subject with reduced heart function, using an shRNA or siRNA. A shRNA is an artificial RNA molecule with a hairpin turn that can be used to silence target gene expression via the siRNA it produces in cells. See, e.g., Fire et. al., Nature 391:806-811, 1998; Elbashir et al., Nature 411:494-498, 2001; Chakraborty et al., Mol Ther Nucleic Acids 8:132-143, 2017; and Bouard et al., Br. J. Pharmacol. 157:153-165, 2009. In some embodiments, a method of treating a subject, e.g., a subject with reduced cardiac function, includes administering to the subject a therapeutically effective amount of a modified RNA or a vector comprising a polynucleotide that encodes an shRNA or siRNA capable of hybridizing to a portion of a 15-PGDH mRNA (e.g., a portion of the human 15-PGDH-encoding polynucleotide sequence set forth in any of GenBank Accession Nos. NM_000860.6, NM_001145816.2, NM_001256301.1, NM_001256305.1, NM_001256306.1, NM_001256307.1, or NM_001363574.1). In some embodiments, the vector further includes appropriate expression control elements known in the art, including, e.g., promoters (e.g., inducible promoters or tissue specific promoters), enhancers, and transcription terminators.

[0091] In some embodiments, the 15-PGDH inhibitor includes or consists of a 15-PGDH- specific microRNA (miRNA or miR). A microRNA is a small non-coding RNA molecule that functions in RNA silencing and post-transcriptional regulation of gene expression. miRNAs base pairs have complementary sequences within the mRNA transcript. As a result, the mRNA transcript may be silenced by one or more of the mechanisms such as cleavage of the mRNA strand, destabilization of the mRNA through shortening of its poly(A) tail, and a decrease in the translation efficiency of the mRNA transcript into proteins by ribosomes.

[0092] In some embodiments, the 15-PGDH inhibitor includes or consists of a morpholino oligomer, an antisense oligonucleotide, e.g., an RNase H-dependent antisense oligonucleotide (ASO), or a combination thereof. ASOs are single-stranded, chemically modified oligonucleotides that bind to complementary sequences in target mRNAs and reduce gene expression both by RNase H-mediated cleavage of the target RNA and by inhibition of translation by steric blockade of ribosomes. In some embodiments, the oligonucleotide is capable of hybridizing to a portion of a 15-PGDH mRNA (e.g., a portion of a human 15-PGDH- encoding polynucleotide sequence as set forth in any of GenBank Accession Nos.NM_000860.6, NM_001145816.2, NM_001256301.1, NM_001256305.1, NM_001256306.1, NM_001256307.1, or NM_001363574.1). In some embodiments, the oligonucleotide has a length of about 10-30 nucleotides (e.g., 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, or 30 nucleotides). In some embodiments, the oligonucleotide has 100% complementarity to the portion of the mRNA transcript it binds. In other embodiments, the DNA oligonucleotide has less than 100% complementarity (e.g., about 95%, about 90%, about 85%, about 80%, about 75%, or about 70% complementarity) to the portion of the mRNA transcript it binds, but can still form a stable RNA:DNA duplex for the RNase H to cleave the mRNA transcript.

[0093] Suitable antisense molecules, siRNA, miRNA, and shRNA can be produced by standard methods of oligonucleotide synthesis or by ordering such molecules from a contract research organization or supplier by providing the polynucleotide sequence being targeted. The manufacture and deployment of such antisense molecules in general terms may be accomplished using standard techniques described in contemporary reference texts: for example, Gene and Cell Therapy: Therapeutic Mechanisms and Strategies, 4thedition by N.S. Templeton; Translating Gene Therapy to the Clinic: Techniques and Approaches, 1stedition by J. Laurence and M. Franklin; High-Throughput RNAi Screening: Methods and Protocols (Methods in Molecular Biology) by D.O. Azorsa and S. Arora; and Oligonucleotide-Based Drugs and Therapeutics: Preclinical and Clinical Considerations by N. Ferrari and R. Segui.

[0094] Inhibitory nucleic acids can also include morpholino oligomers (DNA bases attached to a backbone of methylenemorpholine rings linked through phosphordiamidate groups), which block access to short (approximately 25 bases) specific sequences of the base-pairing surfaces of ribonucleic acid and are used to knock down gene function. Also included are RNA aptamers, which are short, synthetic oligonucleotide sequences that bind to proteins (see, e.g., Li et al., Nuc. Acids Res. (2006), 34:6416-24). Both are notable for both high affinity and specificity for the targeted molecule, and have the additional advantage of being smaller than antibodies (usually less than 6 kD). RNA aptamers with a desired specificity are generally selected from a combinatorial library, and can be modified to reduce vulnerability to ribonucleases, using methods known in the art. 3. Antibodies

[0095] In some embodiments, the 15-PGDH inhibitor includes or consists of an anti-15- PGDH antibody or an antigen-binding fragment thereof. In some embodiments, the antibody is a blocking antibody (e.g., an antibody that binds to a target and directly interferes with thetarget's function, e.g., 15-PGDH enzyme activity). In some embodiments, the antibody is a neutralizing antibody (e.g., an antibody that binds to a target and negates the downstream cellular effects of the target). In some embodiments, the antibody binds to human 15-PGDH.

[0096] In some embodiments, the antibody is a monoclonal antibody. In some embodiments, the antibody is a polyclonal antibody. In some embodiments, the antibody is a chimeric antibody. In some embodiments, the antibody is a humanized antibody. In some embodiments, the antibody is a human antibody. In some embodiments, the antibody is an antigen-bindingfragment, such as a F(ab )2, Fab , Fab, scFv, and the like. The term “antibody or antigen-binding fragment” can also encompass multi-specific and hybrid antibodies, with dual or multiple antigen or epitope specificities.

[0097] For preparing an antibody that binds to 15-PGDH, many techniques known in the art can be used. See, e.g., Kohler & Milstein, Nature 256:495-497 (1975); Kozbor et al., Immunology Today 4: 72 (1983); Cole et al., pp. 77-96 in Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc. (1985); Coligan, Current Protocols in Immunology (1991); Harlow & Lane, Antibodies, A Laboratory Manual (1988); and Goding, Monoclonal Antibodies: Principles and Practice (2nd ed. 1986)). In some embodiments, antibodies are prepared by immunizing an animal or animals (such as mice, rabbits, or rats) with an antigen for the induction of an antibody response. In some embodiments, the antigen is administered in conjugation with an adjuvant (e.g., Freund's adjuvant). In some embodiments, after the initial immunization, one or more subsequent booster injections of the antigen can be administered to improve antibody production. Following immunization, antigen-specific B cells are harvested, e.g., from the spleen and / or lymphoid tissue. For generating monoclonal antibodies, the B cells are fused with myeloma cells, which are subsequently screened for antigen specificity.

[0098] The genes encoding the heavy and light chains of an antibody of interest can be cloned from a cell, e.g., the genes encoding a monoclonal antibody can be cloned from a hybridoma and used to produce a recombinant monoclonal antibody. Gene libraries encoding heavy and light chains of monoclonal antibodies can also be made from hybridoma or plasma cells. Additionally, phage or yeast display technology can be used to identify antibodies and heteromeric Fab fragments that specifically bind to selected antigens (see, e.g., McCafferty et al., Nature 348:552-554 (1990); Marks et al., Biotechnology 10:779-783 (1992); Lou et al. m PEDS 23:311 (2010); and Chao et al., Nature Protocols, 1:755-768 (2006)). Alternatively, antibodies and antibody sequences may be isolated and / or identified using a yeast-basedantibody presentation system, such as that disclosed in, e.g., Xu et al., Protein Eng Des Sel, 2013, 26:663-670; WO 2009 / 036379; WO 2010 / 105256; and WO 2012 / 009568. Random combinations of the heavy and light chain gene products generate a large pool of antibodies with different antigenic specificity (see, e.g., Kuby, Immunology (3rd ed.1997)). Techniques for the production of single chain antibodies or recombinant antibodies (U.S. Patent No. 4,946,778, U.S. Patent No.4,816,567) can also be adapted to produce antibodies.

[0099] Antibodies can be produced using any number of expression systems, including prokaryotic and eukaryotic expression systems. In some embodiments, the expression system is a mammalian cell, such as a hybridoma, or a CHO cell. Many such systems are widely available from commercial suppliers. In embodiments in which an antibody includes both a VH and VL region, the VH and VL regions may be expressed using a single vector, e.g., in a di-cistronic expression unit, or be under the control of different promoters. In other embodiments, the VH and VL region may be expressed using separate vectors.

[0100] In some embodiments, an anti-15-PGDH antibody includes one or more CDR, heavy chain, and / or light chain sequences that are affinity matured. For chimeric antibodies, methods of making chimeric antibodies are known in the art. For example, chimeric antibodies can be made in which the antigen binding region (heavy chain variable region and light chain variable region) from one species, such as a mouse, is fused to the effector region (constant domain) of another species, such as a human. As another example, “class switched” chimeric antibodies can be made in which the effector region of an antibody is substituted with an effector region of a different immunoglobulin class or subclass.

[0101] In some embodiments, an anti-15-PGDH antibody includes one or more CDR, heavy chain, and / or light chain sequences that are humanized. For humanized antibodies, methods of making humanized antibodies are known in the art. See, e.g., US 8,095,890. Generally, a humanized antibody has one or more amino acid residues introduced into it from a source which is non-human. As an alternative to humanization, human antibodies can be generated. As a non-limiting example, transgenic animals (e.g., mice) can be produced that are capable, upon immunization, of producing a full repertoire of human antibodies in the absence of endogenous immunoglobulin production. For example, it has been described that the homozygous deletion of the antibody heavy-chain joining region (JH) gene in chimeric and germ-line mutant mice results in complete inhibition of endogenous antibody production. Transfer of the human germ-line immunoglobulin gene array in such germ-line mutant micewill result in the production of human antibodies upon antigen challenge. See, e.g., Jakobovits et al., Proc. Natl. Acad. Sci. USA, 90:2551 (1993); Jakobovits et al., Nature, 362:255-258 (1993); Bruggermann et al., Year in Immun., 7:33 (1993); and U.S. Patent Nos. 5,591,669, 5,589,369, and 5,545,807.

[0102] In some embodiments, antibody fragments (such as a Fab, a Fab , a F(ab )2, a scFv,nanobody, or a diabody) are generated. Various techniques have been developed for the production of antibody fragments, such as proteolytic digestion of intact antibodies (see, e.g., Morimoto et al., J. Biochem. Biophys. Meth., 24:107-117 (1992); and Brennan et al., Science, 229:81 (1985)) and the use of recombinant host cells to produce the fragments. For example,antibody fragments can be isolated from antibody phage libraries. Alternatively, Fab -SHfragments can be directly recovered from E. coli cells and chemically coupled to form F(ab )2fragments (see, e.g., Carter et al., BioTechnology, 10:163-167 (1992)). According to anotherapproach, F(ab )2 fragments can be isolated directly from recombinant host cell culture. Othertechniques for the production of antibody fragments will be apparent to those skilled in the art.

[0103] Methods for measuring binding affinity and binding kinetics are known in the art. These methods include, but are not limited to, solid-phase binding assays (e.g., ELISA assay), immunoprecipitation, surface plasmon resonance (e.g., Biacore™ (GE Healthcare, Piscataway, NJ)), kinetic exclusion assays (e.g., KinExA®), flow cytometry, fluorescence-activated cell sorting (FACS), BioLayer interferometry (e.g., Octet™ (FortéBio, Inc., Menlo Park, CA)), and western blot analysis. 4. Peptides

[0104] In some embodiments, the 15-PGDH inhibitor includes or consists of a peptide, e.g., a peptide that binds to and / or inhibits the enzymatic activity or stability of 15-PGDH. In some embodiments, the agent is a peptide aptamer. Peptide aptamers are artificial proteins that are selected or engineered to bind to specific target molecules. Typically, the peptides include one or more peptide loops of variable sequence displayed by the protein scaffold. Peptide aptamer selection can be made using different systems, including the yeast two-hybrid system. Peptide aptamers can also be selected from combinatorial peptide libraries constructed by phage display and other surface display technologies such as mRNA display, ribosome display, bacterial display and yeast display. See, e.g., Reverdatto et al., 2015, Curr. Top. Med. Chem. 15:1082-1101.

[0105] In some embodiments, the 15-PGDH inhibitor includes or consists of an affimer. Affimers are small, highly stable proteins, typically having a molecular weight of about 12-14 kDa, that bind their target molecules with specificity and affinity similar to that of antibodies. Generally, an affimer displays two peptide loops and an N-terminal sequence that can be randomized to bind different target proteins with high affinity and specificity in a similar manner to monoclonal antibodies. Stabilization of the two peptide loops by the protein scaffold constrains the possible conformations that the peptides can take, which increases the binding affinity and specificity compared to libraries of free peptides. Affimers and methods of making affimers are described in the art. See, e.g., Tiede et al., eLife, 2017, 6:e24903. Affimers are also commercially available, e.g., from Avacta Life Sciences. 5. Vectors and Modified RNA

[0106] In some embodiments, polynucleotides providing 15-PGDH inhibiting activity or PGE2 upregulation, e.g., a nucleic acid inhibitor such as an siRNA or shRNA, or a polynucleotide encoding a polypeptide that inhibits 15-PGDH, or a nucleic acid that increases expression of PGE2 (for example, an activator of transcription), are introduced into cells, e.g., cardiac cells, using an appropriate vector. Examples of delivery vectors that may be used with the present disclosure are viral vectors, plasmids, exosomes, liposomes, bacterial vectors, or nanoparticles. In some embodiments, any of the herein-described 15-PGDH inhibitor and / or PGE2 activators, e.g., a nucleic acid inhibitor or a polynucleotide encoding a polypeptide inhibitor, are introduced into cells, e.g., cardiac cells, using vectors such as viral vectors. Suitable viral vectors include but not limited to adeno-associated viruses (AAVs), adenoviruses, and lentiviruses. In some embodiments, a 15-PGDH inhibitor and / or PGE2 activator or PGE2 activator, e.g., a nucleic acid inhibitor or expression activator or a polynucleotide encoding a polypeptide inhibitor or expression activator, is provided in the form of an expression cassette, typically recombinantly produced, having a promoter operably linked to the polynucleotide sequence encoding the inhibitor or activator. In some cases, the promoter is a universal promoter that directs gene expression in all or most tissue types; in other cases, the promoter is one that directs gene expression specifically in cells of the tissue being targeted.

[0107] In some embodiments, the nucleic acid or protein inhibitors of 15-PGDH are introduced into a subject, e.g., into the heart of a subject, using modified RNA. Various modifications of RNA are known in the art to enhance, e.g., the translation, potency and / or stability of RNA, e.g., shRNA or mRNA encoding a 15-PGDH polypeptide inhibitor, when introduced into cells of a subject. In particular embodiments, modified mRNA (mmRNA) isused, e.g., mmRNA encoding a polypeptide inhibitor of 15-PGDH. In other embodiments, modified RNA comprising an RNA inhibitor of 15-PGDH expression is used, e.g., siRNA, shRNA, or miRNA. Non-limiting examples of RNA modifications that can be used include anti-reverse-cap analogs (ARCA), polyA tails of, e.g., 100-250 nucleotides in length,replacement of AU-rich sequences in the 3 UTR with sequences from known stable mRNAs,and the inclusion of modified nucleosides and structures such as pseudouridine, e.g., N1-methylpseudouridine, 2-thiouridine, 4 thioRNA, 5-methylcytidine, 6-methyladenosine, amide3 linkages, thioate linkages, inosine, 2 -deoxyribonucleotides, 5-Bromo-uridine and 2 -O-methylated nucleosides. A non-limiting list of chemical modifications that can be used can be found, e.g., in the online database crdd.osdd.net / servers / sirnamod / . RNAs can be introduced into cells in vivo using any known method, including, inter alia, physical disturbance, the generation of RNA endocytosis by cationic carriers, electroporation, gene guns, ultrasound, nanoparticles, conjugates, or high-pressure injection. Modified RNA can also be introduced by direct injection, e.g., in citrate-buffered saline. RNA can also be delivered using self-assembled lipoplexes or polyplexes that are spontaneously generated by charge-to-charge interactions between negatively charged RNA and cationic lipids or polymers, such as lipoplexes, polyplexes, polycations and dendrimers. Polymers such as poly-L-lysine, polyamidoamine,and polyethyleneimine, chitosan, and poly( -amino esters) can also be used. See, e.g., Youn etal. (2015) Expert Opin Biol Ther, Sep 2; 15(9): 1337–1348; Kaczmarek et al. (2017) Genome Medicine 9:60,; Gan et al. (2019) Nature comm.10: 871; Chien et al. (2015) Cold Spring Harb Perspect Med. 5, (2015): a014035; the entire disclosures of each of which are herein incorporated by reference. 6. Gene Editing Systems

[0108] In some embodiments, the 15-PGDH inhibitor includes or consists of a gene editing system with nucleic acid molecules configured to inhibit 15-PGDH and / or activate or upregulate PGE2 synthesis. The nucleic acid molecules may be used in a TALEN (transcription activator-like effector nuclease technology), zinc-finger nuclease or CRISPR-Cas system to target a nucleic acid sequence for genetic screening, targeted transcriptional regulation, targeted knock-in, and targeted genome editing, including base editing, epigenetic editing, and introducing double strand breaks (DSBs) for homologous recombination-mediated insertion of a nucleotide sequence. Genome editing can refer to the targeted modification of a DNA sequence, including but not limited to, adding, removing, replacing, or modifying existing DNA sequences, and inducing chromosomal rearrangements or modifying transcriptionregulation elements (e.g., methylation / demethylation of a promoter sequence of a gene) to alter gene expression. In some embodiments, inhibiting 15-PGDH expression includes inserting a silencer sequence near a polynucleotide sequence encoding 15-PGDH. In yet other embodiments, upregulating PGE2 synthesis includes inserting an enhancer sequence near a polynucleotide sequence encoding PGE2.

[0109] A CRISPR-Cas system requires a guide system that can locate Cas protein to the target DNA site in the genome. In some instances, the guide system includes a CRISPR RNA (crRNA) with a 17-20 nucleotide sequence that is complementary to a target DNA site and a trans-activating crRNA (tracrRNA) scaffold recognized by the Cas protein (e.g., Cas9). The 17-20 nucleotide sequence complementary to a target DNA site is referred to as a spacer while the 17-20 nucleotide target DNA sequence is referred to a protospacer. While crRNAs and tracrRNAs exist as two separate RNA molecules in nature, single guide RNA (sgRNA or gRNA) can be engineered to combine and fuse crRNA and tracrRNA elements into one single RNA molecule. Thus, in one embodiment, the CRISPR guide system includes two or more RNAs, e.g., crRNA and tracrRNA. In another embodiment, the CRISPR guide system includes a sgRNA comprising a spacer sequence for genomic targeting and a scaffold sequence for Cas protein binding. In some instances, the guide system naturally includes a sgRNA. For example, Cas12a / Cpf1 utilizes a guide system lacking tracrRNA and comprising only a crRNA containing a spacer sequence and a scaffold for Cas12a / Cpf1 binding. While the spacer sequence can be varied depending on a target site in the genome, the scaffold sequence for Cas protein binding can be identical for all gRNAs.

[0110] CRISPR-Cas systems described herein can include different CRISPR enzymes. For example, the CRISPR-Cas system can include Cas9, Cas12a / Cpfl, Cas12b / C2cl, Cas12c / C2c3, Cas12d / CasY, Cas12e / CasX, Cas12g, Cas12h, or Cas12i. Non-limiting examples of Cas enzymes include, but are not limited to, Cas1, Cas1B, Cas2, Cas3, Cas4, Cas5, Cas5d, Cas5t, Cas5h, Cas5a, Cas6, Cas7, Cas8, Cas8a, Cas8b, Cas8c, Cas9 (also known as Csn1 or Csx12), Cas10, Cas10d, Cas12a / Cpfl, Cas12b / C2cl, Cas12c / C2c3, Cas12d / CasY, Cas12e / CasX, Cas12f / Cas14 / C2c10, Cas12g, Cas12h, Cas12i, Cas12k / C2c5, Cas13a / C2c2, Cas13b, Cas13c, Cas13d, C2c4, C2c8, C2c9, Csy1, Csy2, Csy3, Csy4, Cse1, Cse2, Cse3, Cse4, Cse5e, Csc1, Csc2, Csa5, Csn1, Csn2, Csm1, Csm2, Csm3, Csm4, Csm5, Csm6, Cmr1, Cmr3, Cmr4, Cmr5, Cmr6, Csb1, Csb2, Csb3, Csx17, Csx14, Csx10, Csx16, CsaX, Csx3, Csx1, Csx1S, Csx11, Csf1, Csf2, CsO, Csf4, Csd1, Csd2, Cst1, Cst2, Csh1, Csh2, Csa1, Csa2, Csa3, Csa4, Csa5, GSU0054, Type II Cas effector proteins, Type V Cas effector proteins, Type VI Cas effectorproteins, CARF, DinG, homologues thereof, or modified or engineered versions thereof such as dCas9 (endonuclease-dead Cas9) and nCas9 (Cas9 nickase that has inactive DNA cleavage domain). In some cases, the compositions, methods, devices, and systems, described herein, may use the Cas9 nuclease from Streptococcus pyogenes, of which amino acid sequences and structures are well known to those skilled in the art.

[0111] Binding of a Cas protein to its target DNA sequence (i.e. target dsDNA) requires the presence of a protospacer adjacent motif (PAM), i.e. a short sequence adjacent to the protospacer, on the non-targeted DNA strand, which limits the region in the genome that can be targeted by Cas proteins. Cas proteins from different bacterial species recognize different PAM sequences and make cuts 3-4 nucleotides upstream (e.g., Cas9) or 18-23 nucleotides downstream (e.g., Cas12a / Cpf1) of the PAM sequence. For example, Cas9 from Streptococcuspyogene recognizes the PAM sequence 5 -NGG-3 (wherein “N” can be any nucleotide) andcleaves 3 nucleotide upstream of the PAM sequence. In another example, Cas9 fromStaphylococcus aureus recognizes the PAM sequence 5 -NNGRRN-3 (wherein “N” can beany nucleotide) and cleaves 4 nucleotide upstream of the PAM sequence. Although the PAM sequence is essential for Cas-mediated cleavage, in some instances, the gRNA sequence does not include a PAM sequence.

[0112] Provided herein are nucleic acid molecules including a target sequence with a spacer that is complementary to a sequence at a target site in the genome. A spacer, as described herein, can include about 10 to about 25 nucleotides in length. For example, a spacer sequence that is complementary to a target site sequence in the genome can be about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or more nucleotides in length. A target site, as described herein, can include a sequence of about 20 nucleotides immediatelyupstream or 5 of the first nucleotide of the PAM. Provided herein are guide system nucleicacid molecules, wherein at least 1, at least 2, or at least 3 consecutive nucleotides at the 5terminus of the guide system nucleic acid molecules are 100% identical to the 3 terminus ofthe target sequence in a genome. Guide system nucleic acid molecules synthesized by the compositions, methods, devises, and systems, described herein, exhibit improved or enhanced pairing with a target sequence via complementary base pairing with the target sequence in atarget gene compared to a guide system nucleic acid molecule comprising additional 5 terminalG nucleotide that is not present in the protospacer sequence or complementary to the 3terminus of the target sequence.

[0113] Provided herein are guide system nucleic acid molecules exhibiting enhanced editing efficiency of a target sequence when guide system nucleic acid molecules are contacted with the target sequence in a complex with a CRISPR-Cas system (e.g., CRISPR-Cas9, CRISPR- Cas12a / Cpf1, etc.). For example, gRNA (guide RNA) provided herein can exhibit enhanced editing efficiency of a target sequence when in complex with a CRISPR-Cas system comparedto a gRNA comprising additional one or more 5 terminal G nucleotides, wherein the additionalone or more 5 terminal G nucleotides are not present in the protospacer sequence or notcomplementary to one or more nucleotides at the 3 terminus of the target sequence in agenome. As used herein, the term “codon” generally refers to three consecutive nucleotides, which may or may not encode an amino acid. As used herein, the “efficiency of editing” or “editing efficiency” can refer to the ability of a guide system nucleic acid molecule directed effector protein (e.g., CRISPR-Cas protein) to modify a target DNA sequence. Non-limiting examples of modification of a target sequence can include introducing a double stranded break, modifying a nucleobase, inducing chromosomal rearrangements, and modifying methylation / demethylation of a promoter sequence of a gene. A target sequence may be located in a gene or in a promoter region in a genome. An effector protein may be a gRNA-directed nuclease, e.g., Cas protein such as Cas9 or any other Cas protein described herein. The editing efficiency can be measured by using any methods well known to one skilled in the art. For example, the efficiency of genome editing or editing efficiency can be measured by using tracking of indels by decomposition (TIDE) analysis, surveyor nuclease assay, junction PCR, droplet digital PCR (ddPCR), denaturing high-performance liquid chromatography (DHPLC), PCR single-stranded conformational polymorphism (SSCP), high-resolution melting (HRM), restriction enzyme digestion-suppressed PCR (RE-PCR), engineered nuclease-induced translocations (ENIT), restriction enzyme digestion, Sanger DNA sequencing, deep sequencing such as next generation sequencing (NGS), or any combination thereof. The term “indel(s)”, as used herein, refers to the insertion or deletion of a nucleotide base within a nucleic acid. In some embodiments, the efficiency of genome editing, e.g., generating a double-strand break, can be measured by TIDE analysis, a three-step method whereby the region targeted by the nuclease (e.g., Cas9) is PCR-amplified from DNA isolated from cells transfected with CRISPR-Cas system and gRNAs. Amplicons of 500-1500 bp generated around the target site are subject to conventional Sanger DNA sequencing followed by analysis using the web-based TIDE software. Any sequence modifications made by the nuclease are visualized in a graph of the sequence with the aberrant base signal. The software also provides precise localization of break sites and estimated statistical significance of each indel. In some embodiments, theediting efficiency, e.g., the efficiency of generating a DNA break in the intended target site, is at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%.

[0114] Further provided herein are guide system nucleic acid molecules that exhibit reduced off-target editing (e.g., editing of a non-target sequence) when guide system nucleic acid molecules are contacted with the target sequence in a complex with a CRISPR-Cas system (e.g., CRISPR-Cas9, CRISPR-Cas12a / Cpf1, etc.). For example, gRNA provided herein can exhibit reduced off-target editing when in complex with a CRISPR-Cas system compared to agRNA comprising additional one or more 5 terminal G nucleotides, wherein the additional oneor more 5 terminal G nucleotides are not present in the protospacer sequence or notcomplementary to one or more nucleotides at the 3 terminus of the target sequence in agenome. In some embodiments, the off-target editing can be reduced by at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%.

[0115] Provided herein are guide system nucleic acid molecules comprising a secondary structure. For example, the scaffold region of the guide system nucleic acid molecule recognized by the Cas protein may form a secondary structure such as a stem, a hairpin, and / or a loop. Stems or hairpins, described herein, can be about 3-10 nucleotides in length. Loops can be about 6-20 nucleotides in length. Stems may include one or more bulges of 1-10 nucleotides in length.

[0116] Further provided herein are guide system nucleic acid molecules including a target sequence with one or more mismatched nucleotide, i.e., the spacer sequence may include one or more nucleotides that are not complementary to the target site sequence in the genome. Spacers described herein may harbor various number of mismatches, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 mismatches. In some embodiments, a spacer includes at most 1, 2, 3, 4, or 5 mismatches. In some embodiments, a spacer does not include any mismatch as compared to a protospacer sequence at the target site, i.e., the spacer 100% hybridizes with the target sequence. Spacers described herein may include at least 1 to at least 5 mismatched nucleotides. For example, the spacer may include at least 1, at least 2, at least 3, at least 4, or at least 5 mismatched nucleotides. In some embodiments, the spacer may include at most 3, at most 4, at most 5, at most 6, or at most 7 mismatched nucleotides. In some embodiments, theone or more mismatched nucleotides may be located at the 5 terminus of the spacer sequence.In some embodiments, the one or more mismatched nucleotides may be located at the 3terminus of the spacer sequence. In some embodiments, the one or more mismatched nucleotides may be internally located in the spacer sequence.

[0117] Provided herein are guide system nucleic acid molecules including a sequenceextension. A sequence extension can be on the 5 or 3 terminus or can be added internally. Forexample, the 5 terminus of the gRNA Cas12a / Cpf1 (e.g., crRNA) can be extended by 2-59nucleotides. Extending the 5 terminus of the Cas12a / Cpf1 gRNA, which includes a scaffoldsequence for Cas12a / Cpf1 binding on the 5 terminus and a target sequence on the 3 terminus,can increase the editing efficiency and delivery of Cas12a / Cpf1 in vitro and in vivo. It can also increase tolerance of gRNAs to chemical modifications, leading to enhanced stability of gRNAs. In another example, a gRNA of Cas9 including an internal extension of 2-10 nucleotides to extend the stem region of the stem loop structure can increases gene knockout efficiency in CRISPR-Cas9-mediated genome editing. In some instances, a gRNA may include two or more of crRNA sequences and tracrRNA sequence and bind two or more Cas proteins and a target DNA sites at two or more distinct regions in the genome. In some embodiments,the gRNAs described herein may include a 5 sequence extension. In some embodiments, thegRNAs described herein may include a 3 sequence extension. In some embodiments, thegRNAs described herein may include an internal sequence extension. In some embodiments, the sequence extension can include about at least 1 to at least 70 nucleotides. In some embodiments, the sequence extension can include at least 1, at least 5, at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, or at least 70 nucleotides.

[0118] Provided herein are guide system nucleic acid molecules including a nucleotide analog, e.g., guanine (G) analog. A nucleotide analog includes an alteration in a phosphate backbone, a sugar, and / or nucleobases. Non-limiting examples of nucleotide analog include 2- aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3-methyl adenosine, 5- methylcytidine, 2-aminoadenosine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5- propynyl-uridine, C5-propynyl-cytidine, C5-methylcytidine, 2-aminoadenosine, 7- deazaadenosine, 7-deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, O(6)-methylguanine, 2-thiocytidine, 2 -fluororibose, ribose, 2 -deoxyribose, arabinose, hexose, phosphorothioatelinkages, 5 -N-phosphoramidite linkages, intercalated bases, and / or chemically modified bases.Provided herein are gRNAs comprising a 5 terminal G analog that can exhibit enhanced editingefficiency of a target sequence when in complex with a CRISPR-Cas system compared to agRNA lacking 5 terminal G analog.

[0119] Further provided herein are nucleic acid molecules including 10 to 100 nucleotides in length. In some embodiments, the synthesized nucleic acid molecules include 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 nucleotides in length. In some embodiments, the synthesized nucleic acid molecules include 10 to 20 nucleotides, 10 to 30 nucleotides, 10 to 40 nucleotides, 10 to 50 nucleotides, 10 to 60 nucleotides, 10 to 70 nucleotides, 10 to 80 nucleotides, 10 to 90 nucleotides, 10 to 100 nucleotides, 20 to 30 nucleotides, 20 to 40 nucleotides, 20 to 50 nucleotides, 20 to 60 nucleotides, 20 to 70 nucleotides, 20 to 80 nucleotides, 20 to 90 nucleotides, 20 to 100 nucleotides, 30 to 40 nucleotides, 30 to 50 nucleotides, 30 to 60 nucleotides, 30 to 70 nucleotides, 30 to 80 nucleotides, 30 to 90 nucleotides, 30 to 100 nucleotides, 40 to 50 nucleotides, 40 to 60 nucleotides, 40 to 70 nucleotides, 40 to 80 nucleotides, 40 to 90 nucleotides, 40 to 100 nucleotides, 50 to 60 nucleotides, 50 to 70 nucleotides, 50 to 80 nucleotides, 50 to 90 nucleotides, 50 to 100 nucleotides, 60 to 70 nucleotides, 60 to 80 nucleotides, 60 to 90 nucleotides, 60 to 100 nucleotides, 70 to 80 nucleotides, 70 to 90 nucleotides, 70 to 100 nucleotides, 80 to 90 nucleotides, 80 to 100 nucleotides, or 90 to 100 nucleotides in length. In some embodiments, the synthesized nucleic acid molecules include at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, or at least 90 nucleotides in length. In some embodiments, the synthesized nucleic acid molecules include at most 20, at most 30, at most 40, at most 50, at most 60, at most 70, at most 80, at most 90, or at most 100 nucleotides in length. In some embodiments, the synthesized nucleic acid molecules include at least 20 nucleotides in length. In some embodiments, the synthesized nucleic acid molecules include at least 80 nucleotides in length. In some embodiments, the synthesized nucleic acid molecules include at most 30 nucleotides in length.

[0120] The synthesized nucleic acid molecules, as described herein, can include one or more modifications. For example, the synthesized nucleic acid molecules can include a synthetic nucleotide, synthetic nucleotide analog, nucleotide derivatives, and / or modified nucleotides. In some embodiments, the one or more modifications can increase stability of the synthesized nucleic acid molecules. In some embodiments, the one or more modification can enhance biological activity of the synthesized nucleic acid molecules. In some embodiments, a modification of internucleotide linkage using phosphorothioate (PS) bond substitutes can be introduced to inhibit exonuclease-mediated degradation of nucleic acid molecules. In some embodiments, the one or more modifications can be made at any location of the synthesized nucleic acid molecule. The synthesized nucleic acid molecule, as described herein, can includenatural nucleosides (e.g., adenosine, guanosine, cytidine, and uridine), nucleoside analogs (e.g., 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3-methyl adenosine, 5- methylcytidine, 2-aminoadenosine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5- propynyl-uridine, C5-propynyl-cytidine, C5-methylcytidine, 2-aminoadenosine, 7- deazaadenosine, 7-deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, O(6)-methylguanine, and 2-thiocytidine), chemically modified bases, biologically modified bases (e.g., methylatedbases), intercalated bases, modified sugars (e.g., 2 -fluororibose, ribose, 2 -deoxyribose,arabinose, and hexose), and / or modified phosphate groups (e.g., phosphorothioates and 5 -N-phosphoramidite linkages).

[0121] Provided herein are nucleic acid molecules including a chemical modification.Chemical modifications as described herein may include one or more 5 modifications selectedfrom the group consisting of 5 triphosphate, 5 diphosphate, 5 monophosphate, and 5hydroxyl. In another embodiment, the chemical modification includes one or more ribosemodifications selected from the group consisting of 2 -O-methylation (2 OMe), 2 -O-methoxy-ethyl (2 -MOE), 2 -fluoro (2 F), 2-deoxy-2 -thio, and 2 -azido. In some embodiments, thechemical modification includes one or more internucleotide linkage modifications selected from the group consisting of phosphorothioate, methylphosphonate, phosphonocarboxylate phosphonothiocarboxylate, boranophosphonate, alkylphosphonate, and alkylphosphonate.

[0122] Chemical modifications can further include modified nucleotides with one or more heterocyclic modifications selected from the group consisting of 2,6-diaminopurine, 2-aminopurine, inosine, 2-aminoadenosine, N6-methyladenosine, N6,2 -O-dimethyladenosine,N1-methyladenosine, 2-amino-6-chloropurineriboside, 5-methylcytidine, 5- hydroxymethylcytidine, 8-oxo-7,8-dihydroguanosine, pseudouridine, N4-acetylcytidine, 5- bromo-uridine, 5-methyluridine, and 5-nitroindole. In some embodiments, the chemicalmodification includes, but is not limited to, modified nucleotides comprising one or more 5cap modifications selected from the group consisting of GpppG, 7-methylguanylate(m7GpppG), m2,2,7GpppG, and m7-3 -OGpppG (ARCA).

[0123] In some instances, the chemical modification includes modified nucleotides with oneor more 5 cap modifications selected from the group consisting of an attachment chemistry(e.g., biotin), a dye, a cell targeting moiety, an active chemistry, and an amino modifier. In some embodiments, the attachment chemistry can include biotin. In some embodiments, the dye includes fluorescein. In some embodiments, the cell targeting moiety includes digoxigenin.In some embodiments, the active chemistry includes azides, acrydite, thiols, or alkynes. In some embodiments, the amino modifier includes aminoallyl. IV. PHARMACEUTICAL COMPOSITIONS

[0124] Also provided herein are pharmaceutical compositions for treating disease, including cardiovascular disease. Each pharmaceutical composition may include one or more molecules, e.g., drugs and inhibitors, of the present disclosure, and a pharmaceutically acceptable carrier or a pharmaceutically acceptable excipient. In some embodiments, the pharmaceutical composition is administered to a subject for therapeutic or prophylactic treatments.

[0125] In therapeutic applications, the pharmaceutical composition can be administered to a subject already suffering from a disease or condition, in an amount sufficient to cure or at least partially arrest the symptoms of the disease or condition, or to cure, heal, improve, or ameliorate the condition. In prophylactic applications, the pharmaceutical composition can be administered to a subject with a propensity or risk of exposure to conditions or diseases in order to prevent the occurrence of the condition or disease. The pharmaceutical composition can be administered to a subject before the onset of symptoms, or during or as soon as possible after the onset of the symptoms.

[0126] The pharmaceutical compositions described herein are administered in a manner compatible with the dosage formulation, and in such amount as will be therapeutically or prophylactically effective. The quantity to be administered depends on a variety of factors including, e.g., the age, body weight, physical activity, and diet of the individual, the disease, disorder, or condition to be treated, and the stage or severity of the disease, disorder, or condition. In certain embodiments, the size of the dose may also be determined by the existence, nature, and extent of any adverse side effects that accompany the administration of a therapeutic agent(s) in a particular individual. It should be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and may depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, hereditary characteristics, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.

[0127] In certain embodiments, the dose of the compound may take the form of solid, semi- solid, lyophilized powder, or liquid dosage forms, such as, for example, tablets, pills, pellets,capsules, powders, solutions, suspensions, emulsions, suppositories, retention enemas, creams, ointments, lotions, gels, aerosols, foams, or the like, preferably in unit dosage forms suitable for simple administration of precise dosages.

[0128] As used herein, the term “unit dosage form” refers to physically discrete units suitable as unitary dosages for humans and other mammals, each unit containing a predetermined quantity of a therapeutic or prophylactic agent calculated to produce the desired onset, tolerability, and / or therapeutic effects, in association with a suitable pharmaceutical excipient (e.g., an ampoule). In addition, more concentrated dosage forms may be prepared, from which the more dilute unit dosage forms may then be produced. The more concentrated dosage forms thus will contain substantially more than, e.g., at least about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, or more times the amount of the therapeutic compound.

[0129] Methods for preparing such dosage forms are known to those skilled in the art (see, e.g., Remington’s Pharmaceutical Sciences, supra). The dosage forms typically include a conventional pharmaceutical carrier or excipient and may additionally include other medicinal agents, carriers, adjuvants, diluents, tissue permeation enhancers, solubilizers, and the like. Appropriate excipients can be tailored to the particular dosage form and route of administration by methods well known in the art (see, e.g., Remington’s Pharmaceutical Sciences, supra).

[0130] Administration of the pharmaceutical composition can be via any route that is suitable for the formulation of the composition. For example, a pharmaceutical composition for intravenous administration can be formulated as a liquid composition with appropriate properties that enable the handling and administration of the composition.

[0131] In some embodiments, the provided pharmaceutical composition is administered in accordance with an acute regimen. In certain instances, the composition is administered to the subject once. In other instances, the composition is administered at one time point, and administered again at a second time point. In yet other instances, the composition is administered to the subject repeatedly (e.g., once or twice daily) as intermittent doses over a short period of time (e.g., 2 days, 3 days, 4 days, 5 days, 6 days, a week, 2 weeks, 3 weeks, 4 weeks, a month, or more). In some cases, the time between administrations is about 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, a week, 2 weeks, 3 weeks, 4 weeks, a month, or more. In other embodiments, the composition is administered continuously or chronically in accordance with a chronic regimen over a desired period of time. For instance, the composition can beadministered such that the amount or level of the compound is substantially constant over a selected time period.

[0132] In some embodiments, the pharmaceutical composition includes a therapeutically effective amount of a pharmaceutically acceptable carrier or a pharmaceutically acceptable excipient. Examples of suitable excipients include, but are not limited to, lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, saline, syrup, methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, and polyacrylic acids such as Carbopols, e.g., Carbopol 941, Carbopol 980, Carbopol 981, etc. In some embodiments, the pharmaceutical composition includes one or more of a diluent, adjuvant, or carrier in a formulation suitable for administration, e.g., administration to a human or other mammals. Suitable diluents, adjuvants, or carriers can include, for example, lipids, e.g., liposomes, e.g., liposome dendrimers; liquids, such as water and oils, including those of petroleum, animal, vegetable, or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like; gum acacia; gelatin; starch paste; talc; keratin; colloidal silica; urea; and the like. Additional examples of suitable diluents include distilled water, buffered water, physiological saline, PBS, Ringer’s solution, dextrose solution, and Hank’s solution. The pharmaceutical composition can also include additional substances to approximate physiological conditions, such as pH adjusting and buffering agents, toxicity adjusting agents, wetting agents, and detergents. In addition, auxiliary, thickening, lubricating, and coloring agents can alternatively or additionally be used. Pharmaceutical compositions can be formulated into preparations in solid, semisolid, liquid, or gaseous forms, such as tablets, capsules, powders, granules, ointments, solutions, suppositories, injections, inhalants, gels, microspheres, and aerosols.

[0133] The pharmaceutical composition can also include any of a variety of stabilizing agents, such as an antioxidant for example. When the pharmaceutical composition includes a polypeptide, the polypeptide can be complexed with various well-known compounds that enhance the in vivo stability of the polypeptide, or otherwise enhance its pharmacological properties (e.g., increase the half-life of the polypeptide, reduce its toxicity, and / or enhance solubility or uptake). Examples of such modifications or complexing agents include sulfate, gluconate, citrate, and phosphate. The nucleic acids or polypeptides of a composition can also be complexed with molecules that enhance their in vivo attributes. Such molecules include, forexample, carbohydrates, polyamines, amino acids, other peptides, ions (e.g., sodium, potassium, calcium, magnesium, manganese), and lipids. V. KITS

[0134] In another aspect, the disclosure provides kits for improving the cardiac function of a subject. The provided kits generally include a 15-PGDH inhibitor, and can additionally or alternatively include a PGE2 activator. The kit typically contains containers, which may be formed from a variety of materials such as glass or plastic, and can include for example, bottles, vials, syringes, and test tubes. A label typically accompanies the kit, and includes any writing or recorded material, which may be electronic or computer readable form providing instructions or other information for use of the kit contents.

[0135] In some embodiments, the provided kit includes one or more reagents for the treatment of a heart with reduced cardiac function. In some embodiments, the kit includes one or more reagents for the treatment of a heart in a subject with an age-related condition, disorder, or disease. In some embodiments, the kit includes an agent, e.g., a small molecule drug, that antagonizes the expression or activity of 15-PGDH. In some embodiments, the kit includes an inhibitory nucleic acid (e.g., a morpholino oligomer, an antisense DNA or RNA, small interfering RNA (siRNA), microRNA (miRNA), short hairpin RNA (shRNA)), or a polynucleotide encoding a 15-PGDH inhibiting polypeptide, that inhibits or suppresses 15- PGDH mRNA or protein expression or activity, e.g., enzyme activity. In some embodiments, the kit includes a modified RNA, e.g., a modified shRNA or siRNA, or a modified mRNA encoding a polypeptide 15-PGDH inhibitor and / or PGE2 activator. In some embodiments, the kit further includes one or more plasmid, bacterial or viral vectors for expression of the inhibitory nucleic acid or polynucleotide encoding a 15-PGDH-inhibiting polypeptide. In some embodiments, the kit includes a peptide nucleic acid (PNA), a morpholino oligomer, an aptamer, antisense oligonucleotide capable of hybridizing to a portion of a 15-PGDH-encoding mRNA. In some embodiments, the kit includes an antibody (e.g., a monoclonal, polyclonal, humanized, bispecific, chimeric, blocking or neutralizing antibody) or antibody-binding fragment thereof that specifically binds to and inhibits a 15-PGDH protein. In some embodiments, the kit includes a blocking peptide. In some embodiments, the kit includes an aptamer (e.g., a peptide or nucleic acid aptamer). In some embodiments, the kit includes an affimer. In some embodiments, the kit includes a modified RNA. In particular embodiments, the kit includes a combination with a small molecule inhibitor, e.g., SW033291, that binds to15-PGDH or inhibits its enzymatic activity. In some embodiments, the kit further includes one or more additional therapeutic agents, e.g., agents for administering in combination therapy with the agent that antagonizes the expression or activity of 15-PGDH and / or enhances the expression or activity of PGE2.

[0136] In some embodiments, the kits can further include instructional materials containing directions (e.g., protocols) for the practice of the methods described herein (e.g., instructions for using the kit for enhancing the cardiac function of a subject. While the instructional materials typically include written or printed materials, they are not limited to such. Any medium capable of storing such instructions and communicating them to an end user is contemplated by this disclosure. Such media include, but are not limited to, electronic storage media (e.g., magnetic discs, tapes, cartridges, chips), optical media (e.g., CD ROM), and the like. Such media may include addresses to internet sites that provide such instructional materials. VI. EXEMPLARY EMBODIMENTS

[0137] The following embodiments are contemplated. All combinations of features and embodiments are contemplated.

[0138] Embodiment 1: A method of improving cardiac function in a subject, the method comprising reducing 15-hydroxyprostaglandin dehydrogenase (15-PGDH) activity in the heart of the subject.

[0139] Embodiment 2: An embodiment of embodiment 1, wherein the method further comprises increasing a level of prostaglandin E2 (PGE2) in the heart of the subject.

[0140] Embodiment 3: An embodiment of embodiment 1 or 2, wherein the reducing of the 15-PGDH activity comprises administering to the subject a therapeutically effective amount of a 15-PGDH inhibitor.

[0141] Embodiment 4: An embodiment of embodiment 3, wherein the 15-PGDH inhibitor comprises a small molecule drug.

[0142] Embodiment 5: An embodiment of embodiment 4, wherein the small molecule drug comprises 2-(butylsulfinyl)-4-phenyl-6-(thiophen-2-yl)thieno[2,3-b]pyridin-3-amine (SW033291).

[0143] Embodiment 6: An embodiment of any one of embodiments 3-5, wherein the 15- PGDH inhibitor comprises a nucleic acid molecule.

[0144] Embodiment 7: An embodiment of embodiment 6, wherein the nucleic acid molecule comprises a peptide nucleic acid (PNA), an aptamer, an antisense oligonucleotide, a morpholino oligomer, microRNA, siRNA, shRNA, or a combination thereof.

[0145] Embodiment 8: An embodiment of any one of embodiments 3-7, wherein the 15- PGDH inhibitor comprises a gene editing system.

[0146] Embodiment 9: An embodiment of embodiment 8, wherein the gene editing system comprises a CRISPR-Cas system, a zinc-finger nuclease system, a transcription activator-like effector nuclease (TALEN) system, or a combination thereof.

[0147] Embodiment 10: An embodiment of embodiment 9, wherein the gene editing system comprises the CRISPR-Cas system.

[0148] Embodiment 11: An embodiment of embodiment 10, wherein the CRISPR-Cas system comprises a Cas endonuclease coupled to a guide RNA (gRNA) targeting at least a portion of a polynucleotide sequence encoding 15-PGDH.

[0149] Embodiment 12: An embodiment of embodiment 11, wherein the Cas endonuclease is Cas9 endonuclease.

[0150] Embodiment 13: An embodiment of any one of embodiments 8-12, wherein the method comprises using the gene editing system to insert a silencer sequence near a polynucleotide sequence encoding 15-PGDH, thereby inhibiting 15-PGDH expression.

[0151] Embodiment 14: An embodiment of any one of embodiments 8-13, wherein the administering results in inhibition of transcription factors that negatively regulate the enhancer or promoter of the HPGD gene.

[0152] Embodiment 15: An embodiment of any one of embodiments 3-14, wherein the 15- PGDH inhibitor comprises a polypeptide.

[0153] Embodiment 16: An embodiment of embodiment 15, wherein the polypeptide comprises an antibody, a nanobody, or a combination thereof.

[0154] Embodiment 17: An embodiment of any one of embodiments 1-16, wherein reducing 15-PGDH activity comprises reducing or blocking expression of 15-PGDH.

[0155] Embodiment 18: An embodiment of any one of embodiments 1-16, wherein reducing 15-PGDH activity comprises reducing or blocking enzymatic activity of 15-PGDH.

[0156] Embodiment 19: An embodiment of any one of embodiments 1-18, wherein the subject exhibits a cardiomyopathy prior to the reducing of the 15-PGDH activity.

[0157] Embodiment 20: An embodiment of embodiment 19, wherein the cardiomyopathy comprises dilated cardiomyopathy (DCM).

[0158] Embodiment 21: An embodiment of embodiment 19 or 20, wherein the cardiomyopathy comprises Duchenne muscular dystrophy (DMD) cardiomyopathy.

[0159] Embodiment 22: An embodiment of any one of embodiments 19-21, wherein the cardiomyopathy comprises a heritable myopathy caused by a mutation in a gene.

[0160] Embodiment 23: An embodiment of embodiment 22, wherein the gene comprisesTTN (titin), TNNT2 (troponin T), TPM1 ( -tropomyosin), RBM20 (encoding RNA bindingmotif protein 20), BAG3 (BLC2-associated athanogene 3), DES (desmin), FLNC (filamin-C), LMNA (lamin A / C), MYH7 (myosin heavy chain 7), PLN (phospholamban), SCN5A (sodium channel -subunit), TNNC1 (troponin C), DSP (desmoplakin), ACTC1 (cardiac -actin),ACTN2 ( -actinin-2), JPH2 (Junctophilin 2), NEXN (nexilin), TNNI3 (troponin I), VCL(vinculin), or a combination thereof.

[0161] Embodiment 24: An embodiment of any one of embodiments 1-21, wherein the subject exhibits age-related reduced cardiac metabolism prior to the reducing of the 15-PGDH activity.

[0162] Embodiment 25: An embodiment of embodiment 24, wherein the age-related reduced cardiac metabolism comprises an altered cardiac glucose uptake relative to a cardiac glucose uptake exhibited by the subject at a younger age.

[0163] Embodiment 26: An embodiment of any one of embodiments 1-25, wherein the subject has one or more biomarkers of aging.

[0164] Embodiment 27: An embodiment of embodiment 26, wherein the one or more biomarkers of aging comprise an increase in 15-PGDH levels relative to a young individual, a decrease in PGE2 levels relative to a young individual, an increase in a PGE2 metabolite relative to a young individual, an increase or a greater accumulation of senescent cells relative to a young individual, an increase in expression of one or more atrogenes relative to a youngindividual, a decrease in mitochondria biogenesis and / or function relative to a young individual, an increase in transforming growth factor pathway signaling relative to a young individual, or a combination thereof.

[0165] Embodiment 28: An embodiment of any one of embodiments 1-27, wherein the method further comprises increasing a left ventricular fractional shortening (FS) cardiac output of the subject.

[0166] Embodiment 29: An embodiment of any one of embodiments 1-28, wherein the method further comprises increasing a left ventricular ejection fraction (LVEF) of the subject.

[0167] Embodiment 30: An embodiment of any one of embodiments 1-29, wherein the method further comprises increasing endogenous expression of a mitochondrial gene by the subject.

[0168] Embodiment 31: An embodiment of any one of embodiments 1-30, wherein the method further comprises restoring cardiac glucose uptake by the subject to within 25% of a cardiac glucose uptake exhibited by the subject at a younger age.

[0169] Embodiment 32: An embodiment of any one of embodiments 1-31, wherein the subject is a human. EXAMPLES

[0170] The present disclosure will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes only, and are not intended to limit the disclosure in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters which can be changed or modified to yield essentially the same results.

[0171] The provided examples involve reducing 15-PGDH activity using a small molecule drug to increase endogenous PGE2 levels and improve cardiac function. Specifically, by using the TM54 mouse line–a transgenic model expressing cardiac tropomyosin with a patient- induced mutation leading to Dilated Cardiomyopathy (DCM), which shows reduced cardiac function and an enlarged left ventricle similar to that observed in human DCM (Rajan, S. et al., Circ. Res. (2007): 101; Arif, M. et al. Cells 10, (2021): 771)–it was observed that systemic inhibition of 15-PGDH rescued cardiac function and concurrently mitigated cardiac fibrosis. These findings demonstrate that the materials and compositions disclosed herein provide important therapeutic tools for addressing a broad spectrum of cardiac disorders.

[0172] These examples demonstrate that 15-PGDH inhibition can improve cardiac function in patients suffering from, for example, DCM and / or DMD, and indicate that an overall metabolic improvement can be achieved in the aged heart. These findings therefore have applications to the treatment of cardiomyopathy in several cardiac diseases. Example 1. Treatment of dilated cardiomyopathy by 15-PGDH inhibition

[0173] The inhibition of the PGE2 degrading enzyme, 15-PGDH, by the small molecule SW033291 (SW) was found to result in enhanced regeneration by stem cells and rejuvenation of aged skeletal muscle myofibers (Palla, A. R. et al., Science 371, (2021): eabc8059; Ho, A. T. V. et al., Proc. Natl. Acad. Sci. U.S.A.114, (2017): 6675). This Example relates to inhibition of 15-PGDH by SW, thereby ameliorating cardiac dysfunction in a dilated cardiomyopathy mouse model. The tested TM54 mice provide a transgenic model expressing cardiac tropomyosin with a mutation found in human pedigrees that leads to dilated cardiomyopathy (FIG. 2A). Results demonstrate that one month of daily intraperitoneal injection of this drug significantly increased cardiac function measured as the fractional shortening (FS) and left ventricular ejection fraction (LVEF) (Figures 2B-D). Example 2. Treatment of Duchenne muscular dystrophy by 15-PGDH inhibition

[0174] The SW033291 (SW) drug was tested in a second mouse model of cardiac dysfunction – the mdx / mTRG2, a “humanized” Duchenne muscular dystrophy (DMD) mouse model with shorter telomere lengths like humans, which by the second generation recapitulates the severity of DMD cardiomyopathy, exhibiting dilated cardiomyopathy, cardiac fibrosis, and mitochondrial dysfunction (Mourkioti, F. et al., Nat. Cell Biol. 15, (2013): 895; Chang, A. C. Y. et al., Proc. Natl. Acad. Sci. U.S.A. 113, (2016): 13120). Thirty-two week-old, second generation, mdx / mTR (mdx / mTRG2) mice were treated for 4 weeks with daily intraperitoneal injections of the SW033291 (SW) (FIG.3A). Results demonstrate that the treatment increased the heart FS and LVEF (Figures 3B-D). Example 3. Improvement of cardiac function in an aged heart by 15-PGDH inhibition

[0175] The SW033291 (SW) drug was tested in a third mouse model – aged mice. Results provided evidence of improved cardiac function. Twenty-seven-month-old WT mice were treated for four weeks with SW033291 (SW). A transcriptomic analysis revealed an increase in expression of mitochondrial genes, constituting a restoration to levels found in young mice (FIG. 4A). Additionally, in glucose uptake experiments, the drug treatment overcame thedecrease in cardiac glucose uptake observed in aging (FIG.4B). These data suggest a metabolic rejuvenation in the aged heart by inhibition of 15-PGDH.

[0176] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub- combination. All combinations of the embodiments pertaining to the disclosure are specifically embraced by the present disclosure and are disclosed herein just as if each and every combination was individually and explicitly disclosed. In addition, all sub-combinations of the various embodiments and elements thereof are also specifically embraced by the present disclosure and are disclosed herein just as if each and every such sub- combination was individually and explicitly disclosed herein.

[0177] Although the foregoing disclosure has been described in some detail by way of illustration and example for purpose of clarity of understanding, one of skill in the art will appreciate that certain changes and modifications within the spirit and scope of the disclosure may be practiced, e.g., within the scope of the appended claims. It should also be understood that aspects of the disclosure and portions of various recited embodiments and features can be combined or interchanged either in whole or in part. In the foregoing descriptions of the various embodiments, those embodiments which refer to another embodiment may be appropriately combined with other embodiments as will be appreciated by one of skill in the art. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the disclosure. In addition, each reference provided herein is incorporated by reference in its entirety for all purposes to the same extent as if each reference was individually incorporated by reference.

Claims

WHAT IS CLAIMED IS:

1. A method of improving cardiac function in a subject, the method comprising reducing 15-hydroxyprostaglandin dehydrogenase (15-PGDH) activity in the heart of the subject.

2. The method of claim 1, wherein the method further comprises increasing a level of prostaglandin E2 (PGE2) in the heart of the subject.

3. The method of claim 1, wherein the reducing of the 15-PGDH activity comprises administering to the subject a therapeutically effective amount of a 15-PGDH inhibitor.

4. The method of claim 3, wherein the 15-PGDH inhibitor comprises a small molecule drug.

5. The method of claim 4, wherein the small molecule drug comprises 2- (butylsulfinyl)-4-phenyl-6-(thiophen-2-yl)thieno[2,3-b]pyridin-3-amine (SW033291).

6. The method of claim 3, wherein the 15-PGDH inhibitor comprises a nucleic acid molecule.

7. The method of claim 6, wherein the nucleic acid molecule comprises a peptide nucleic acid (PNA), an aptamer, an antisense oligonucleotide, a morpholino oligomer, microRNA, siRNA, shRNA, or a combination thereof.

8. The method of claim 3, wherein the 15-PGDH inhibitor comprises a gene editing system.

9. The method of claim 8, wherein the gene editing system comprises a CRISPR-Cas system, a zinc-finger nuclease system, a transcription activator-like effector nuclease (TALEN) system, or a combination thereof.

10. The method of claim 9, wherein the gene editing system comprises the CRISPR-Cas system.

11. The method of claim 10, wherein the CRISPR-Cas system comprises a Cas endonuclease coupled to a guide RNA (gRNA) targeting at least a portion of a polynucleotide sequence encoding 15-PGDH.

12. The method of claim 11, wherein the Cas endonuclease is Cas9 endonuclease.

13. The method of claim 8, wherein the method comprises using the gene editing system to insert a silencer sequence near a polynucleotide sequence encoding 15- PGDH, thereby inhibiting 15-PGDH expression.

14. The method of claim 8, wherein the administering results in inhibition of transcription factors that negatively regulate the enhancer or promoter of the HPGD gene.

15. The method of claim 3, wherein the 15-PGDH inhibitor comprises a polypeptide.

16. The method of claim 15, wherein the polypeptide comprises an antibody, a nanobody, or a combination thereof.

17. The method of claim 1, wherein reducing 15-PGDH activity comprises reducing or blocking expression of 15-PGDH.

18. The method of claim 1, wherein reducing 15-PGDH activity comprises reducing or blocking enzymatic activity of 15-PGDH.

19. The method of claim 1, wherein the subject exhibits a cardiomyopathy prior to the reducing of the 15-PGDH activity.

20. The method of claim 19, wherein the cardiomyopathy comprises dilated cardiomyopathy (DCM).

21. The method of claim 19, wherein the cardiomyopathy comprises Duchenne muscular dystrophy (DMD) cardiomyopathy.

22. The method of any one of claims 19-21, wherein the cardiomyopathy comprises a heritable myopathy caused by a mutation in a gene.

23. The method of claim 22, wherein the gene comprises TTN (titin), TNNT2(troponin T), TPM1 ( -tropomyosin), RBM20 (encoding RNA binding motif protein 20), BAG3(BLC2-associated athanogene 3), DES (desmin), FLNC (filamin-C), LMNA (lamin A / C), MYH7 (myosin heavy chain 7), PLN (phospholamban), SCN5A (sodium channel -subunit),TNNC1 (troponin C), DSP (desmoplakin), ACTC1 (cardiac -actin), ACTN2 ( -actinin-2),JPH2 (Junctophilin 2), NEXN (nexilin), TNNI3 (troponin I), VCL (vinculin), or a combination thereof.

24. The method of claim 1, wherein the subject exhibits age-related reduced cardiac metabolism prior to the reducing of the 15-PGDH activity.

25. The method of claim 24, wherein the age-related reduced cardiac metabolism comprises an altered cardiac glucose uptake relative to a cardiac glucose uptake exhibited by the subject at a younger age.

26. The method of claim 1, wherein the subject has one or more biomarkers of aging.

27. The method of claim 26, wherein the one or more biomarkers of aging comprise an increase in 15-PGDH levels relative to a young individual, a decrease in PGE2 levels relative to a young individual, an increase in a PGE2 metabolite relative to a young individual, an increase or a greater accumulation of senescent cells relative to a young individual, an increase in expression of one or more atrogenes relative to a young individual, a decrease in mitochondria biogenesis and / or function relative to a young individual, an increase in transforming growth factor pathway signaling relative to a young individual, or a combination thereof.

28. The method of claim 1, wherein the method further comprises increasing a left ventricular fractional shortening (FS) cardiac output of the subject.

29. The method of claim 1, wherein the method further comprises increasing a left ventricular ejection fraction (LVEF) of the subject.

30. The method of claim 1, wherein the method further comprises increasing endogenous expression of a mitochondrial gene by the subject.

31. The method of claim 1, wherein the method further comprises restoring cardiac glucose uptake by the subject to within 25% of a cardiac glucose uptake exhibited by the subject at a younger age.

32. The method of claim 1, wherein the subject is a human.

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