Wnt surrogate molecules and uses thereof

Abstract

To provide binding moieties that specifically bind to one or more Fzd, LRP5, or LRP6 to modulate Wnt signaling pathways.SOLUTION: In one embodiment, the disclosure provides a soluble, divalent and bispecific Wnt surrogate molecule comprising: (i) one or more regions that specifically bind to one or more frizzled (Fzd) receptors (a Fzd binding region); (ii) one or more regions that bind to low density lipoprotein (LDL) receptor-related protein 5 (LRP5) and / or low density lipoprotein (LDL) receptor-related protein 6 (LRP6) (a LRP5 / 6 binding region).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 62 / 607,875, filed December 19, 2017, U.S. Provisional Application No. 62 / 641,217, filed March 9, 2018, and U.S. Provisional Application No. 62 / 680,522, filed June 4, 2018, each of which is incorporated by reference in its entirety.

[0002] Description of sequence listing The sequence listing accompanying the present invention is provided in text format in lieu of a paper copy and is incorporated herein by reference. The name of the text file containing the sequence listing is SRZN_006_03WO_ST25.txt. This text file is 1.2MB, was created on December 19, 2018, and has been submitted electronically via EFS-Web.

[0003] The present invention relates generally to Wnt signaling pathway agonist molecules and compositions and methods of use employing Wnt signaling pathway agonist molecules. Such molecules are useful, for example, in modulating the Wnt signaling pathway. [Background technology]

[0004] Wnt ("Wingless-associated integration site" or "Wingless and Int-1" or "Wingless-Int") ligands and their signals play important roles in regulating the development, homeostasis, and regeneration of many essential organs and tissues, including bone, liver, skin, stomach, intestine, kidney, central nervous system, mammary gland, taste buds, ovary, cochlea, and many other tissues (reviewed, for example, by Clevers, Loh, and Nusse, 2014;346:1248012). Modulation of the Wnt signaling pathway has potential for the treatment of degenerative diseases and tissue injury. One of the challenges of modulating Wnt signaling as a therapeutic agent is the existence of multiple Wnt ligands and Wnt receptors, Frizzled 1-10 (Fzd1-10), with many tissues expressing multiple overlapping Fzds. In addition to Fzds, canonical Wnt signaling also involves low density lipoprotein (LDL) receptor-related protein 5 (LRP5) or low density lipoprotein (LDL) receptor-related protein 6 (LRP6) as co-receptors, which are widely expressed in various tissues. Thus, there is a clear need in the art for binding moieties that specifically bind one or more Fzds, LRP5, or LRP6 to modulate the Wnt signaling pathway. The present invention addresses this need. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Clevers,Loh,and Nusse,2014;346:1248012 Summary of the Invention [Means for solving the problem]

[0006] In various embodiments, the present invention provides WNT surrogate molecules and related uses thereof.

[0007] In one embodiment, the present disclosure provides a soluble, bivalent and bispecific Wnt surrogate molecule comprising: (i) one or more regions that specifically bind to one or more frizzled (Fzd) receptors (Fzd-binding regions); and (ii) one or more regions that specifically bind to low-density lipoprotein (LDL) receptor-related protein 5 (LRP5) and / or low-density lipoprotein (LDL) receptor-related protein 6 (LRP6) (LRP5 / 6-binding regions).

[0008] In certain embodiments, the Wnt surrogate molecule comprises two or more Fzd binding regions and two or more LRP5 / 6 binding regions. In certain embodiments, the one or more Fzd binding regions comprise one or more antigen-binding fragments of an antibody. In certain embodiments, the one or more antigen-binding fragments are selected from the group consisting of IgG, scFv, Fab, and VHH or sdAb.

[0009] In certain embodiments, any of the Fzd antigen-binding fragments comprises (i) the CDRH1, CDRH2, and CDRH3 sequences set forth for any of the antibodies in Table 1A or 1B, and / or (ii) the CDRL1, CDRL2, and CDRL3 sequences set forth for any of the antibodies in Table 1A or 1B, or a variant of such Fzd binding region comprising one or more amino acid modifications, wherein the variant comprises fewer than eight amino acid substitutions in the CDR sequences. In certain embodiments, any of the Fzd binding regions comprises an amino acid sequence having at least 90% identity to any of the sequences set forth in SEQ ID NOs: 1-65 or 129-132, or an antigen-binding fragment thereof.

[0010] In certain embodiments, any Fzd binding region binds to one or more of Frizzled 1 (Fzd1), Frizzled 2 (Fzd2), Frizzled 3 (Fzd3), Frizzled 4 (Fzd4), Frizzled 5 (Fzd5), Frizzled 6 (Fzd6), Frizzled 7 (Fzd7), Frizzled 8 (Fzd8), Frizzled 9 (Fzd9), and Frizzled 10 (Fzd10). In certain embodiments, any Fzd binding region binds to two or more of Frizzled 1 (Fzd1), Frizzled 2 (Fzd2), Frizzled 3 (Fzd3), Frizzled 4 (Fzd4), Frizzled 5 (Fzd5), Frizzled 6 (Fzd6), Frizzled 7 (Fzd7), Frizzled 8 (Fzd8), Frizzled 9 (Fzd9), and Frizzled 10 (Fzd10). In certain embodiments, any Fzd binding region binds to: (i) Fzd1, Fzd2, Fzd7, and Fzd9; (ii) Fzd1, Fzd2, and Fzd7; (iii) Fzd5 and Fzd8; (iv) Fzd5, Fzd7, and Fzd8; (v) Fzd1, Fzd4, Fzd5, and Fzd8; (vi) Fzd1, Fzd2, Fzd5, Fzd7, and Fzd8; (vii) Fzd4 and Fzd9; (viii) Fzd9 and Fzd10; (ix) Fzd5, Fzd8, and Fzd10; (x) Fzd4, Fzd5, and Fzd8; Fzd1, Fzd5, Fzd7, and Fzd8.

[0011] In certain embodiments, any of the surrogate molecules comprises one or more LRP5 / 6 binding regions comprising one or more antigen binding fragments of an antibody. In certain embodiments, the one or more antigen binding fragments are selected from the group consisting of an IgG, an scFv, a Fab, and a VHH or an sdAb. In certain embodiments, any of the one or more LRP5 / 6 binding regions or antigen binding fragments comprises (i) the CDRH1, CDRH2, and CDRH3 sequences set forth for any of the antibodies in Table 2, and / or (ii) the CDRL1, CDRL2, and CDRL3 sequences set forth for any of the antibodies in Table 2, or a variant of such an LRP5 / 6 binding region comprising one or more amino acid modifications, wherein the variant comprises fewer than eight amino acid substitutions in the CDR sequences. In certain embodiments, any of the one or more LRP5 / 6 binding regions comprises an amino acid sequence having at least 90% identity to any of the sequences set forth in SEQ ID NOs: 66-88 or 133, or an antigen binding fragment thereof.

[0012] In certain embodiments of any Wnt surrogate molecule, the Fzd binding region comprises a Fab and the LRP5 / 6 binding region comprises a VHH or sdAb. In certain embodiments, the Fab is present in a whole immunoglobulin (Ig) including light and heavy chains, optionally in an IgG. In certain embodiments, the LRP5 / 6 binding region is fused to the N-terminus or C-terminus of the heavy chain. In certain embodiments, the LRP5 / 6 binding region is fused to the N-terminus or C-terminus of the light chain. In certain embodiments, the LRP5 / 6 binding region is fused to the N-terminus of the heavy chain of a whole Ig or the N-terminus of the light chain of a whole Ig. In certain embodiments, the LRP5 / 6 binding region is fused to the C-terminus of the heavy chain of a whole Ig or the C-terminus of the light chain of a whole Ig. In certain embodiments, the variable light chain region of the LRP5 / 6 binding Fab is fused to the N-terminus of the variable heavy chain region of a whole Ig. In certain embodiments, the variable light chain region of the LRP5 / 6 binding Fab is fused to the N-terminus of the variable heavy chain region of a whole Ig, and the variable heavy chain region of the LRP5 / 6 binding Fab is fused to the N-terminus of the variable light chain region of a whole IgG. In certain embodiments, any LRP5 / 6 binding region is fused to a heavy or light chain via one or more linker moieties.

[0013] In certain embodiments of any Wnt surrogate molecule, the Fzd binding region comprises a VHH or sdAb and the LRP5 / 6 binding region comprises a Fab. In certain embodiments, the Fab is present in a whole immunoglobulin (Ig) including light and heavy chains, optionally in an IgG. In certain embodiments, the Fzd binding region is fused to the N-terminus or C-terminus of the heavy chain. In certain embodiments, the Fzd binding region is fused to the N-terminus or C-terminus of the light chain. In some embodiments, the Fzd binding region is fused to the N-terminus of the heavy chain of the whole Ig or the N-terminus of the light chain of the whole Ig. In some embodiments, the Fzd binding region is fused to the C-terminus of the heavy chain of the whole Ig or the C-terminus of the light chain of the whole Ig. In some embodiments, the variable light chain region of the Fzd binding Fab is fused to the N-terminus of the variable heavy chain region of the whole Ig. In some embodiments, the variable light chain region of the Fzd-binding Fab is fused to the N-terminus of the variable heavy chain region of a whole Ig, and the variable heavy chain region of the Fzd-binding Fab is fused to the N-terminus of the variable light chain region of a whole IgG, In certain embodiments, any Fzd-binding region is fused to a heavy or light chain via one or more linker moieties.

[0014] In another embodiment, any Fzd binding region comprises a Fab or Fv, and the LRP5 / 6 binding region comprises a Fab or Fv. In certain embodiments, the Fab of the Fzd binding region or the Fab of the LRP5 / 6 binding region is present in a whole immunoglobulin (Ig) including light and heavy chains, optionally in an IgG. In certain embodiments, only one of the Fab of the Fzd binding region or the Fab of the LRP5 / 6 binding region is present in a whole immunoglobulin (Ig). In certain embodiments, the Fab or Fv of the Fzd binding region is present in a whole Ig. In certain embodiments, the Fab of the LRP5 / 6 binding region is fused to the N-terminus of the Ig. In certain embodiments, the Fab of the LRP5 / 6 binding region is fused to the C-terminus of the Ig. In a further embodiment, the Fab of the LRP5 / 6 binding region is present in a whole Ig. In certain embodiments, the Fab of the Fzd binding region is fused to the N-terminus of the Ig. In certain embodiments, the Fab of the Fzd binding region is fused to the C-terminus of the Ig. In some embodiments, the variable light chain region of the Fzd-binding Fab is fused to the N-terminus of the variable heavy chain region of the whole Ig, and the variable heavy chain region of the Fzd-binding Fab is fused to the N-terminus of the variable light chain region of the whole IgG. In some embodiments, the variable light chain region of the LRP5 / 6-binding Fv is fused to the N-terminus of the variable heavy chain region of the whole Ig, and the variable heavy chain region of the LRP5 / 6-binding Fv is fused to the N-terminus of the variable light chain region of the whole IgG. In some embodiments, the variable light chain region of the Fzd-binding Fv is fused to the N-terminus of the variable heavy chain region of the whole Ig, and the variable light chain region of the LRP5 / 6-binding Fv is fused to the N-terminus of the variable light chain region of the whole IgG. In some embodiments, the variable light chain region of the Fzd-binding Fv is fused to the N-terminus of the variable heavy chain region of the whole Ig, and the variable heavy chain region of the Fzd-binding Fv is fused to the N-terminus of the variable light chain region of the whole IgG. In some embodiments, the variable heavy chain region of an Fzd-binding Fv is fused to the N-terminus of the variable heavy chain region of an entire Ig, and the variable light chain region of an Fzd-binding Fv is fused to the N-terminus of the variable light chain region of an entire IgG.

[0015] In another embodiment, any Fzd binding region comprises a VHH or sdAb, and the LRP5 / 6 binding region comprises a VHH or sdAb. In a specific embodiment, the Fzd binding region is fused to the Lrp5 / 6 binding region, and the Fzd binding region or the LRP5 / 6 binding region is fused to an Fc region. In a specific embodiment, the Fzd binding region is fused to the N-terminus of the Fc region, and the LRP5 / 6 binding region is fused to the C-terminus of the Fc region. In a specific embodiment, the Fzd binding region is fused to the C-terminus of the Fc region, and the LRP5 / 6 binding region is fused to the N-terminus of the Fc region.

[0016] In a further embodiment, any of the antibodies or one or more antigen-binding fragments thereof are humanized. In a further embodiment, any of the Wnt surrogate molecules has a K of 50 μM or less for one or more Fzd receptors. D In a further embodiment, any Wnt surrogate molecule binds to LRP5 and / or LRP6 with a K of 50 μM or less. D Combine with.

[0017] In further embodiments, any Wnt surrogate molecule regulates the Wnt signaling pathway in a cell, optionally in a mammalian cell. In certain embodiments, the Wnt surrogate molecule increases signaling through the Wnt signaling pathway in a cell. In certain embodiments, the Wnt signaling pathway is the canonical Wnt signaling pathway or the non-canonical Wnt signaling pathway.

[0018] In related embodiments, the disclosure provides an isolated polynucleotide encoding a polypeptide sequence comprising one or more of the Fzd-binding regions and / or one or more of the LRP5 / 6-binding regions of a Wnt surrogate molecule. In certain embodiments, the disclosure provides an expression vector comprising the isolated polynucleotide. In further particular embodiments, the disclosure provides an isolated host cell comprising the expression vector.

[0019] In a related embodiment, the disclosure provides a pharmaceutical composition comprising a physiologically acceptable excipient, diluent, or carrier and a therapeutically effective amount of any of the Wnt surrogate molecules disclosed herein.

[0020] In a related embodiment, the disclosure provides a method for stimulating the Wnt signaling pathway in a cell, comprising contacting the cell with any Wnt surrogate molecule, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway.

[0021] In certain embodiments, the disclosure provides a method for treating a subject having a disease or disorder associated with reduced Wnt signaling, comprising administering to the subject an effective amount of a pharmaceutical composition, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. In certain embodiments, the disease or disorder is bone fracture, osteoporosis (e.g., postmenopausal osteoporosis), osteoporotic fracture, spinal fusion, spinal compression fracture, preoperative optimization of spinal surgery, osseointegration of orthopedic devices, tendon-osseointegration, tooth growth and regeneration, dental implants, periodontal disease, maxillofacial reconstruction, osteonecrosis of the jaw, osteoarthritis (OA), muscular dystrophies, muscle atrophy due to sarcopenia or cachexia, alopecia, hearing loss (including regeneration of inner and outer hair cells), vestibular hypofunction, macular degeneration, vitreous retinopathy, retinal degenerative diseases (including diabetic retinopathy), diseases / disorders affecting the integrity of the blood-brain barrier, Fuchs' dystrophy, stroke, traumatic brain injury, Alzheimer's disease, multiple sclerosis, spinal cord injury, oral mucositis, short bowel syndrome, inflammatory bowel disease (IBD) (including chronic myocardial infarction, chronic obstructive pulmonary disease, chronic kidney disease, chronic obstructive pulmonary disease, chronic myocardial infarction, chronic obstructive pulmonary disease ... The disease or condition is selected from the group consisting of: Rohn's disease (CD) and ulcerative colitis (UC), including IBD, especially with fistulizing disease, metabolic syndrome, diabetes, dyslipidemia, pancreatitis, exocrine pancreatic insufficiency, wound healing, diabetic foot ulcer, coronary artery disease, acute kidney injury, chronic kidney disease, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (including idiopathic pulmonary fibrosis), acute liver failure, acute alcoholic liver injury, chronic liver disease due to hepatitis C virus (HCV), HCV subjects after antiviral therapy, chronic liver disease due to hepatitis B virus (HBV), fibrosis, HBV subjects after antiviral therapy, chronic alcoholic liver disease, alcoholic hepatitis, nonalcoholic fatty liver disease and nonalcoholic steatohepatitis (NASH), cirrhosis, and chronic liver failure of any cause. In certain embodiments, the disease or condition is a bone disease or disorder. In certain embodiments, the disease or disorder is a bone disease or disorder and the Wnt surrogate molecule binds to Fzd1, Fzd2, and FZD7, and binds to LRP5 and / or LRP6. In certain embodiments, the disease or disorder is a bone disease or disorder and the Wnt surrogate molecule binds to Fzd1, Fzd2, FZD7, Fzd5, and Fzd8, and also binds to LRP5 and / or LRP6.

[0022] In another related embodiment, the present disclosure provides a method for increasing bone mineral density, increasing bone volume, increasing bone cortical thickness, increasing bone mineral apposition rate, increasing bone stiffness, increasing bone biomechanical strength, increasing resistance to fracture, decreasing bone resorption, or decreasing osteoporosis-related bone loss in a subject in need thereof, comprising providing to the subject an effective amount of a pharmaceutical composition comprising a Wnt surrogate molecule, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. In certain embodiments, the Wnt surrogate molecule binds to Fzd1, Fzd2, and FZD7, and binds to LRP5 and / or LRP6. In certain embodiments, the Wnt surrogate molecule binds to Fzd1, Fzd2, FZD7, Fzd5, and Fzd8, and also binds to LRP5 and / or LRP6.

[0023] In certain embodiments, the method of the present invention, including the method related to the treatment or prevention of bone disease or bone disorder, such as osteoporosis (e.g., postmenopausal osteoporosis), further comprises providing a bone resorption inhibitor (combined with Wnt surrogate molecule) to the subject. Examples of bone resorption inhibitors include, but are not limited to, bisphosphonates or selective estrogen receptor modulators. Bone resorption inhibitors are used to increase bone strength in individuals with osteoporosis, and include five major drug classes: bisphosphonates, estrogens, selective estrogen receptor modulators (SERMs), calcitonin, and monoclonal antibodies such as denosumab, any of which may be used. Illustrative examples of bone antiresorptive agents include, but are not limited to, bisphosphonates, such as the drug commonly referred to as alendronate (trade names: Fosamax™, Fosamax™ Plus D), risedronate (trade names: Actonel™, Actonel™ with calcium), ibandronate (trade name: Boniva™), and zoledronic acid (trade name: Reclast™); other bone antiresorptive agents, such as estrogen or hormone therapy, raloxifene (trade name: Evista™), and denosumab (Prolial™); and anabolic agents, such as teriparatide (Forteo™).

[0024] In further related embodiments, the present disclosure provides a method for increasing liver-to-body weight ratio, promoting liver regeneration, increasing hepatocyte proliferation or mitosis, reducing liver fibrosis, optionally following chronic liver injury, increasing hepatocyte function, or reducing clotting time in the liver in a subject in need thereof, comprising providing to the subject an effective amount of a pharmaceutical composition comprising a Wnt surrogate molecule, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. In certain embodiments, for example, the following are provided: (Item 1) A soluble, multivalent and multispecific Wnt surrogate molecule comprising: (i) one or more regions that specifically bind to one or more frizzled (Fzd) receptors (Fzd binding regions); and (ii) one or more regions that specifically bind to low density lipoprotein (LDL) receptor-related protein 5 (LRP5) and / or low density lipoprotein (LDL) receptor-related protein 6 (LRP6) (LRP5 / 6 binding regions). (Item 2) 2. The Wnt surrogate molecule of item 1, comprising one or more Fzd-binding regions and one or more LRP5 / 6-binding regions. (Item 3) The Wnt surrogate molecule of item 1, wherein the one or more Fzd binding regions comprise one or more antigen-binding fragments of an antibody. (Item 4) The Wnt surrogate molecule of item 3, wherein the one or more antigen-binding fragments are selected from the group consisting of IgG, scFv, Fab, and VHH or single domain antibody (sdAb). (Item 5) 5. The Wnt surrogate molecule of any of items 3-4, wherein the one or more Fzd antigen-binding fragments comprise (i) the CDRH1, CDRH2, and CDRH3 sequences set forth for any of the antibodies of Table 1A or 1B, and / or (ii) the CDRL1, CDRL2, and CDRL3 sequences set forth for any of the antibodies of Table 1A or 1B, or a variant of the Fzd-binding region comprising one or more amino acid modifications, wherein the variant comprises fewer than eight amino acid substitutions in the CDR sequences. (Item 6) 6. The Wnt surrogate molecule according to any one of items 3 to 5, wherein the one or more Fzd-binding regions comprise an amino acid sequence having at least 90% identity to any one of the sequences set forth in SEQ ID NOs: 1 to 65 or 129 to 132, or an antigen-binding fragment thereof. (Item 7) 7. The Wnt surrogate molecule according to any one of items 1 to 6, wherein the one or more Fzd binding regions bind to one or more of frizzled 1 (Fzd1), frizzled 2 (Fzd2), frizzled 3 (Fzd3), frizzled 4 (Fzd4), frizzled 5 (Fzd5), frizzled 6 (Fzd6), frizzled 7 (Fzd7), frizzled 8 (Fzd8), frizzled 9 (Fzd9), and frizzled 10 (Fzd10). (Item 8) 8. The Wnt surrogate molecule of item 7, wherein the one or more Fzd binding regions bind to two or more of frizzled 1 (Fzd1), frizzled 2 (Fzd2), frizzled 3 (Fzd3), frizzled 4 (Fzd4), frizzled 5 (Fzd5), frizzled 6 (Fzd6), frizzled 7 (Fzd7), frizzled 8 (Fzd8), frizzled 9 (Fzd9), and frizzled 10 (Fzd10). (Item 9) 9. The Wnt surrogate molecule of item 8, wherein the one or more Fzd binding regions bind to: (i) Fzd1, Fzd2, Fzd7, and Fzd9; (ii) Fzd1, Fzd2, and Fzd7; (iii) Fzd5 and Fzd8; (iv) Fzd5, Fzd7, and Fzd8; (v) Fzd1, Fzd4, Fzd5, and Fzd8; (vi) Fzd1, Fzd2, Fzd5, Fzd7, and Fzd8; (vii) Fzd4 and Fzd9; (viii) Fzd9 and Fzd10; (ix) Fzd5, Fzd8, and Fzd10; (x) Fzd4, Fzd5, and Fzd8; Fzd1, Fzd5, Fzd7, and Fzd8. (Item 10) 10. The Wnt surrogate molecule according to any of items 1 to 9, wherein the one or more LRP5 / 6 binding regions comprise one or more antigen-binding fragments of an antibody. (Item 11) 11. The Wnt surrogate molecule of item 10, wherein the one or more antigen-binding fragments are selected from the group consisting of IgG, scFv, Fab, and VHH or sdAb. (Item 12) 12. The Wnt surrogate molecule of any of items 1 to 11, wherein the one or more LRP5 / 6 binding regions or antigen-binding fragments comprise (i) the CDRH1, CDRH2, and CDRH3 sequences set forth for any of the antibodies in Table 2, and / or (ii) the CDRL1, CDRL2, and CDRL3 sequences set forth for any of the antibodies in Table 2, or a variant of the LRP5 / 6 binding region comprising one or more amino acid modifications, wherein the variant comprises fewer than eight amino acid substitutions in the CDR sequences. (Item 13) 13. The Wnt surrogate molecule according to any one of items 10 to 12, wherein the one or more LRP5 / 6 binding regions comprise an amino acid sequence having at least 90% identity to any of the sequences set forth in SEQ ID NOs: 66 to 88 or 133, or an antigen-binding fragment thereof. (Item 14) 14. The Wnt surrogate according to any of items 1 to 13, wherein the Fzd-binding region and the LRP5 / 6-binding region comprise a sequence as set forth in Table 3 for any of the Wnt surrogates disclosed herein. (Item 15) 15. The Wnt surrogate molecule according to any of items 1 to 14, wherein the Fzd-binding region comprises a Fab and the LRP5 / 6-binding region comprises a VHH or a sdAb or a scFv. (Item 16) 16. The Wnt surrogate molecule of item 15, wherein the Fab is present within a whole immunoglobulin (Ig) including a light chain and a heavy chain, optionally within an IgG. (Item 17) 17. The Wnt surrogate molecule of item 16, wherein the LRP5 / 6 binding region is fused to the N-terminus or C-terminus of the heavy chain or fused to the N-terminus or C-terminus of the light chain. (Item 18) 18. The Wnt surrogate molecule of item 17, wherein the LRP5 / 6 binding region is fused to the heavy chain or the light chain via one or more linker moieties. (Item 19) 15. The Wnt surrogate molecule according to any of items 1 to 14, wherein the Fzd-binding region comprises a VHH or an sdAb or an scFv, and the LRP5 / 6-binding region comprises a Fab. (Item 20) 20. The Wnt surrogate molecule of item 19, wherein the Fab is present within a whole immunoglobulin (Ig) including a light chain and a heavy chain, optionally within an IgG. (Item 21) 21. The Wnt surrogate molecule of item 20, wherein the Fzd binding region is fused to the N-terminus or C-terminus of the heavy chain. (Item 22) 21. The Wnt surrogate molecule of item 20, wherein the Fzd binding region is fused to the N-terminus or C-terminus of the light chain. (Item 23) 23. The Wnt surrogate molecule of claim 21 or 22, wherein the Fzd binding region is fused to the heavy chain or the light chain via one or more linker moieties. (Item 24) 15. The Wnt surrogate molecule according to any of items 1 to 14, wherein the Fzd-binding region comprises a Fab or Fv, and the LRP5 / 6-binding region comprises a Fab or Fv. (Item 25) 25. The Wnt surrogate molecule of item 24, wherein the Fab of the Fzd binding region or the Fab of the LRP5 / 6 binding region is present within a whole immunoglobulin (Ig) including a light chain and a heavy chain, optionally within an IgG. (Item 26) 26. The Wnt surrogate molecule of item 25, wherein only one of the Fab of the Fzd binding region or the Fab of the LRPp5 / 6 binding region is present in the whole immunoglobulin (Ig). (Item 27) 27. The Wnt surrogate molecule of item 26, wherein the Fab of the Fzd binding region is present within the whole Ig. (Item 28) 28. The Wnt surrogate molecule of item 27, wherein the Fab or Fv of the LRP5 / 6 binding region is fused to the N-terminus of the Ig, optionally to the N-terminus of the heavy chain of the whole Ig or the N-terminus of the light chain of the whole Ig. (Item 29) 28. The Wnt surrogate molecule of item 27, wherein the Fab of the LRP5 / 6 binding region is fused to the C-terminus of the Ig, optionally to the C-terminus of the heavy chain of the whole Ig or the C-terminus of the light chain of the whole Ig. (Item 30) 28. The Wnt surrogate molecule of item 27, wherein the variable light chain region of the LRP5 / 6 binding Fab is fused to the N-terminus of the variable heavy chain region of the whole Ig. (Item 31) 28. The Wnt surrogate molecule of item 27, wherein the variable light chain region of the LRP5 / 6 binding Fab is fused to the N-terminus of the variable heavy chain region of the whole Ig and the variable heavy chain region of the LRP5 / 6 binding Fab is fused to the N-terminus of the variable light chain region of the whole IgG. (Item 32) 28. The Wnt surrogate molecule of item 27, wherein the variable light chain region of the LRP5 / 6 binding Fv is fused to the N-terminus of the variable heavy chain region of the whole Ig and the variable heavy chain region of the LRP5 / 6 binding Fv is fused to the N-terminus of the variable light chain region of the whole IgG. (Item 33) 28. The Wnt surrogate molecule of item 27, wherein the variable heavy chain region of the LRP5 / 6 binding Fv is fused to the N-terminus of the variable heavy chain region of the whole Ig, and the variable light chain region of the LRP5 / 6 binding Fv is fused to the N-terminus of the variable light chain region of the whole IgG. (Item 34) 27. The Wnt surrogate molecule of item 26, wherein the Fab of the LRP5 / 6 binding region is present within the whole Ig. (Item 35) 35. The Wnt surrogate molecule of item 34, wherein the Fab or Fv of the Fzd binding region is fused to the N-terminus of the Ig, optionally to the N-terminus of the heavy chain of the whole Ig or the N-terminus of the light chain of the whole Ig. (Item 36) 35. The Wnt surrogate molecule of item 34, wherein the Fab or Fv of the Fzd binding region is fused to the C-terminus of the Ig, optionally to the C-terminus of the heavy chain of the whole Ig or the C-terminus of the light chain of the whole Ig. (Item 37) 35. The Wnt surrogate molecule of item 34, wherein the variable light chain region of the Fzd-binding Fab is fused to the N-terminus of the variable heavy chain region of the whole Ig. (Item 38) 35. The Wnt surrogate molecule of item 34, wherein the variable light chain region of the Fzd-binding Fab is fused to the N-terminus of the variable heavy chain region of the whole Ig and the variable heavy chain region of the Fzd-binding Fab is fused to the N-terminus of the variable light chain region of the whole IgG. (Item 39) 36. The Wnt surrogate molecule of claim 34 or 35, wherein the variable light chain region of the Fzd-binding Fv is fused to the N-terminus of the variable heavy chain region of the whole Ig and the variable heavy chain region of the Fzd-binding Fv is fused to the N-terminus of the variable light chain region of the whole IgG. (Item 40) 36. The Wnt surrogate molecule of claim 34 or 35, wherein the variable heavy chain region of the Fzd-binding Fv is fused to the N-terminus of the variable heavy chain region of the whole Ig and the variable light chain region of the Fzd-binding Fv is fused to the N-terminus of the variable light chain region of the whole IgG. (Item 41) 15. The Wnt surrogate molecule according to any one of items 1 to 14, wherein the Fzd binding region comprises a VHH or a sdAb or a scFv, and the LRP5 / 6 binding region comprises a VHH or a sdAb or a scFv. (Item 42) 42. The Wnt surrogate molecule of item 41, wherein the Fzd-binding region is fused to the Lrp5 / 6-binding region, and the Fzd-binding region or the LRP5 / 6-binding region is fused to an Fc region. (Item 43) 42. The Wnt surrogate molecule of item 41, wherein the Fzd binding region is fused to the N-terminus of an Fc region and the LRP5 / 6 binding region is fused to the C-terminus of an Fc region. (Item 44) 42. The Wnt surrogate molecule of item 41, wherein the Fzd binding region is fused to the C-terminus of an Fc region and the LRP5 / 6 binding region is fused to the N-terminus of an Fc region. (Item 45) 15. The Wnt surrogate molecule according to any one of items 1 to 14, wherein the surrogate molecule has a structure depicted in Figure 1A-D, 10A, 15A, 16A, or 18A. (Item 46) 46. ​​The Wnt surrogate molecule according to any of items 1 to 45, wherein the one or more antigen-binding fragments thereof are humanized. (Item 47) 47. The Wnt surrogate molecule according to any one of items 1 to 46, which binds to the one or more Fzd receptors with a KD of 50 μM or less. (Item 48) 48. The Wnt surrogate molecule according to any one of items 1 to 47, which binds to the one or more LRP5 / 6 receptors with a KD of 50 μM or less. (Item 49) 49. The Wnt surrogate molecule of any of items 1 to 48, which regulates the Wnt signaling pathway in a cell, optionally a mammalian cell. (Item 50) 50. The Wnt surrogate of item 49, wherein the Wnt signaling pathway is a canonical Wnt signaling pathway or a non-canonical Wnt signaling pathway. (Item 51) 51. The Wnt surrogate molecule of item 49 or item 50, which increases signaling through the Wnt signaling pathway in the cell. (Item 52) 52. An isolated polynucleotide encoding a polypeptide sequence comprising one or more of the Fzd-binding regions and / or one or more of the LRP5 / 6-binding regions of the Wnt surrogate molecule according to any one of items 1 to 51. (Item 53) 53. An expression vector comprising the isolated polynucleotide of item 52. (Item 54) 54. An isolated host cell comprising the expression vector of item 53. (Item 55) A pharmaceutical composition comprising a physiologically acceptable excipient, diluent, or carrier and a therapeutically effective amount of a Wnt surrogate molecule according to any one of items 1 to 51, a polynucleotide according to item 52, an expressing cell according to item 53, or a host cell according to item 54. (Item 56) A method for stimulating the Wnt signaling pathway in a cell, comprising contacting the cell with a Wnt surrogate molecule according to any one of items 1 to 51, a polynucleotide according to item 52, an expressing cell according to item 53, or a host cell according to item 54, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. (Item 57) A method for treating a subject having a disease or disorder associated with reduced Wnt signaling, comprising administering to the subject an effective amount of a Wnt surrogate molecule according to any one of items 1 to 51, a polynucleotide according to item 52, an expression cell according to item 53, a host cell according to item 54, or a pharmaceutical composition according to item 55, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. (Item 58) 58. The method of item 57, wherein the disease or disorder is a bone disease or disorder. (Item 59) 59. The method of item 58, wherein the Wnt surrogate molecule binds to Fzd1, Fzd2, and FZD7, and binds to LRP5 and / or LRP6. (Item 60) 60. The method of item 59, wherein the Wnt surrogate molecule also binds to Fzd5 and Fzd8. (Item 61) The disease or disorder may be bone fracture, stress fracture, vertebral compression fracture, osteoporosis, osteoporotic fracture, nonunion fracture, delayed union fracture, spinal fusion, preoperative optimization for spinal surgery, osteonecrosis, osseointegration of implants or orthopedic devices, osteogenesis imperfecta, bone grafting, tendon repair, tendon-osseointegration, tooth growth and regeneration, maxillofacial surgery, dental implants, periodontal disease, maxillofacial reconstruction, osteonecrosis of the jaw, hip, or femoral head, avascular necrosis, alopecia, hearing loss, reduced vestibular function, macular degeneration, age-related macular degeneration (AMD), ), vitreoretinopathy, retinopathy, diabetic retinopathy, retinal degenerative diseases, Fuchs' dystrophy, corneal diseases, stroke, traumatic brain injury, Alzheimer's disease, multiple sclerosis, muscular dystrophies, muscle atrophy caused by sarcopenia and cachexia, diseases affecting the integrity of the blood-brain barrier (BBB), spinal cord injury, spinal cord diseases, oral mucositis, short bowel syndrome, inflammatory bowel disease (IBD), metabolic syndrome, diabetes, dyslipidemia, pancreatitis, exocrine pancreatic insufficiency, wound healing , diabetic foot ulcers, pressure ulcers, venous leg ulcers, epidermolysis bullosa, cutis hypoplasia, myocardial infarction, coronary artery disease, heart failure, hematopoietic cell disorders, immunodeficiency, graft-versus-host disease, acute kidney injury, chronic kidney disease, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, acute liver failure of any cause, drug-induced acute liver failure, alcoholic liver disease (including alcoholic hepatitis), chronic liver failure of any cause, cirrhosis, hepatic fibrosis of any cause, portal hypertension, chronic liver failure of any cause, non-alcoholic 58. The method of claim 57, wherein the liver disease or disorder is selected from the group consisting of nonalcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD) (fatty liver), alcoholic hepatitis, hepatitis C virus-induced liver disease (HCV), hepatitis B virus-induced liver disease (HBV), other viral hepatitis (e.g., hepatitis A virus-induced liver disease (HAV) and hepatitis D virus-induced liver disease (HDV)), primary biliary cirrhosis, autoimmune hepatitis, liver surgery, liver injury, liver transplantation, "small for size" syndrome in liver surgery and transplantation, congenital liver disease and liver damage, genetic disease, degeneration, aging, drugs, or any other liver damage or detection due to injury. (Item 62) 56. A method for increasing bone mineral density, increasing bone volume, increasing bone cortical thickness, increasing bone mineral apposition rate, increasing bone stiffness, increasing bone biomechanical strength, increasing resistance to fracture, or reducing bone loss associated with osteoporosis, comprising providing to a subject an effective amount of the pharmaceutical composition of item 55, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. (Item 63) 63. The method of item 62, wherein the Wnt surrogate molecule binds to Fzd1, Fzd2, and FZD7, and binds to LRP5 and / or LRP6. (Item 64) 64. The method of item 63, wherein the Wnt surrogate molecule also binds to Fzd5 and Fzd8. (Item 65) 56. A method for increasing liver-to-body weight ratio, promoting liver regeneration, increasing hepatocyte proliferation or mitosis, reducing liver fibrosis, optionally after chronic liver injury, increasing hepatocyte function, or reducing clotting time in the liver, comprising providing to a subject an effective amount of the pharmaceutical composition of item 55, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. (Item 66) 66. The method according to any of items 57 to 65, further comprising providing to the subject a bone resorption inhibitor. (Item 67) 67. The method according to item 66 for the treatment of osteoporosis, optionally postmenopausal osteoporosis. (Item 68) A method for inhibiting or reducing bone resorption in a subject in need thereof, comprising providing to the subject an effective amount of a Wnt surrogate molecule according to any one of items 1 to 51, a polynucleotide according to item 52, an expressing cell according to item 53, a host cell according to item 54, or a pharmaceutical composition according to item 55, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway. (Item 69) 70. The method of claim 68, further comprising providing to the subject a bone resorption inhibitor. (Item 70) 70. The method of claim 68 or claim 69, wherein the subject has been diagnosed with or is at risk of osteoporosis, optionally postmenopausal osteoporosis. [Brief description of the drawings]

[0025] [Figure 1] 1A-D are schematic diagrams of exemplary formats of Wnt surrogate molecules. [Figure 2-1] 2A-2D show the characterization of the Wnt surrogate molecule R2M3-26. [Figure 2-2] Same as above. [Figure 3-1] 3A-3D show the characterization of the Wnt surrogate molecule R2M3-32. [Figure 3-2] Same as above. [Figure 4] 4A-4B are graphs showing that the activity of R2M3-26 and R2M3-32 can be inhibited by soluble Fzd ECD and by R2M3 IgG alone without the Lrp binding arm. [Figure 5-1] FIG. 5 shows characterization of exemplary R2M3-Lrp6 binder fusions in 293, Huh7, A375, and BNL.CL2 Wnt-dependent reporter assays. [Figure 5-2] Same as above. [Figure 5-3] Same as above. [Figure 5-4] Same as above. [Figure 6-1] FIG. 6 shows the characterization of exemplary 18R5-Lrp6 binder fusions in 293, A375, and BNL.CL2 Wnt-dependent reporter assays. [Figure 6-2] Same as above. [Figure 7] FIG. 7 shows the characterization of exemplary 18R5-Lrp5 binder fusions in a 293 Wnt-dependent reporter assay. [Figure 8] 8A-8B show the characterization of exemplary Fzd-binder-Lrp6-binder26 fusions in a 293 Wnt-dependent reporter assay. [Figure 9] FIG. 9 shows SAR analysis of exemplary Wnt surrogate molecules in IgG-Nab fusion format. [Figure 10] 10A-10B show the characterization of R2M3-26 in Fab format in a 293 Wnt-dependent reporter assay. [Figure 11] 11A-11B show the characterization of R2M3-32 in Fab format in a 293 Wnt-dependent reporter assay. [Figure 12] 12A-12B show the characterization of R2M3-26 in a hetero-Ig format in a 293 Wnt-dependent reporter assay. [Figure 13-1] FIG. 13 shows the characterization of 26-17SB9 in a VHH / sdAb-VHH / sdAb format, in different tandem formats and on different ends of the Fc fragment in a 293 Wnt-dependent reporter assay. [Figure 13-2] Same as above. [Figure 13-3] Same as above. [Figure 13-4] Same as above. [Figure 14-1] 14A-14H show the characterization of 18R5-LRP6 binder fusions in tandem scFv format in a 293 Wnt-dependent reporter assay. [Figure 14-2] Same as above. [Figure 14-3] Same as above. [Figure 15-1] 15A-15G show the characterization of various Wnt surrogate molecules in Fab-IgG format in a 293 Wnt-dependent reporter assay. [Figure 15-2] Same as above. [Figure 16]16A-16C show the characterization of R2M3-26 in F(ab')2 format in a 293 Wnt-dependent reporter assay. [Figure 17-1] 17A-17H show the characterization of additional Wnt surrogate molecules in 293 Wnt-dependent reporter assays. [Figure 17-2] Same as above. [Figure 17-3] Same as above. [Figure 17-4] Same as above. [Figure 17-5] Same as above. [Figure 17-6] Same as above. [Figure 17-7] Same as above. [Figure 18] A is a schematic diagram of the 2Fv-Ig format, and B-C show the characterization of the Wnt surrogate molecule 10SG11-1RC07. [Figure 19-1] FIG. 19 is the sequence of the polypeptide chain of an exemplary Wnt surrogate molecule. [Figure 19-2] Same as above. [Figure 19-3] Same as above. [Figure 19-4] Same as above. [Figure 19-5] Same as above. [Figure 19-6] Same as above. [Figure 19-7] Same as above. [Figure 19-8] Same as above. [Figure 19-9] Same as above. [Figure 19-10] Same as above. [Figure 19-11] Same as above. [Figure 19-12] Same as above. [Figure 19-13] Same as above. [Figure 19-14] Same as above. [Figure 19-15] Same as above. [Figure 19-16] Same as above. [Figure 19-17] Same as above. [Figure 19-18] Same as above. [Figure 19-19] Same as above. [Figure 19-20] Same as above. [Figure 19-21] Same as above. [Figure 19-22] Same as above. [Figure 20] 20A-20B show the in vivo PK / PD characterization of R2M3-26. [Figure 21-1] Figures 21A-21E are images and graphs showing that systemic expression of 18R5-DKK1c for 14 days results in increased bone mineral density. *P value < 0.05; **P value < 0.0001. For each time point, bars from left to right indicate: vehicle (diamond), romosozumab (square), AAV CAG-GFP (triangle), AAB ScFv(anti-GFP)-DKK1cF234K-Flag-His (inverted triangle), and AAV 18R5-DKK1c-FLagHis (circle). [Figure 21-2] Same as above. [Figure 21-3] Same as above. [Figure 22-1] 22A-22D are images and graphs showing that systemic expression of 18R5-DKK1c for 14 or 28 days results in increased bone volume. For each time point, bars from left to right represent: vehicle, romosozumab, AAV CAG-GFP, AAB ScFv(anti-GFP)-DKK1cF234K-Flag-His, and AAV 18R5-DKK1c-FLagHis. *P value<0.05; **P value<0.0001, ****P value<0.0001. [Figure 22-2] Same as above. [Figure 22-3] Same as above. [Diagram 23] 23A-23B are graphs showing dynamic parameters of bone formation based on fluorescent dye labeling. For each time point, the bars from left to right represent: vehicle, romosozumab, AAV CAG-GFP, AAB ScFv(anti-GFP)-DKK1cF234K-Flag-His, and AAV 18R5-DKK1c-FlagHis. [Figure 24-1]24A-24D are graphs and images showing that systemic expression of 18R5-DKK1c results in increased osteoblasts and reduced osteoclasts at the bone surface. For each time point, bars from left to right represent: vehicle, romosozumab, AAV CAG-GFP, AAB ScFv(anti-GFP)-DKK1cF234K-Flag-His, and AAV 18R5-DKK1c-FlagHis. **P value<0.05. [Figure 24-2] Same as above. [Figure 25-1] 25A-25C are diagrams of assays for bone stiffness and fracture, as well as graphs showing ultimate load and stiffness to failure in mice treated as indicated. [Figure 25-2] Same as above. [Figure 26-1] 26A-26D are graphs and images showing that systemic treatment with R2M3-26 results in rapid and sustained increases in bone after one week. For each time point, the bars from left to right correspond to the treatments indicated from top to bottom. **** indicates a P value <0.0001. [Figure 26-2] Same as above. [Figure 26-3] Same as above. [Figure 26-4] Same as above. [Figure 27-1] 27A-27C are images and graphs showing that R2M3-26 treatment rapidly reverses bone loss associated with ovariectomy-induced osteoporosis. For each time point, the bars from left to right correspond to the treatments shown from top to bottom. [Figure 27-2] Same as above. [Figure 28-1] 28A-28C are images and graphs showing that a single injection of R2M3-26 rapidly increases bone volume. [Figure 28-2] Same as above. [Figure 28-3] Same as above. [Figure 29-1]29A-29D are graphs showing that high doses of R2M3-26 and 1R-C07-26 significantly and rapidly increase bone formation in naive mice. For each time point, the bars from left to right correspond to the treatments indicated from top to bottom. [Figure 29-2] Same as above. [Figure 29-3] Same as above. [Diagram 30] 30 is a graph showing that R2M3-26 and 1R-C07-3 increase bone mineral density in naive mice. For each time point, the bars from left to right correspond to the treatments indicated from top to bottom. [Diagram 31] FIG. 31 is a graph showing changes in whole body bone mineral density (BMD) measured weekly in ovariectomized mice compared to naive and sham-operated mice. [Diagram 32] FIG. 32 shows the change in vertebral bone mineral density (images shown) and the change in resistance to vertebral compression fracture measured in Newtons of force (bar graph) in vertebrae isolated from mice after various treatments. [Figure 33-1] Figure 33A-D: Testing of Wnt surrogate molecules in the Einhorn fracture model. Radiographs of the callus are shown after 1 week (A) and 6 weeks (B) of treatment with Wnt surrogate molecules. Photographs of the change in total body bone mineral density (BMD) in the contralateral femur are shown (C). Scatter plots showing the change in callus tissue volume, callus volume, bone volume / tissue volume ratio (BV / TV), and bone mineral content per milliliter (BMC / mm) as shown in (D) are shown along with representative images of bone sections. [Figure 33-2] Same as above. [Figure 33-3] Same as above. [Figure 33-4] Same as above. [Figure 33-5] Same as above. [Figure 33-6] Same as above. [Figure 33-7] Same as above. [Diagram 34]FIG. 34 is a graph of the change in total body bone mineral density (BMD) measured weekly with different Wnt surrogate molecule administration schedules. [Diagram 35] FIG. 35 is a graph of the change in total body bone mineral density (BMD) measured weekly from mice treated with different Wnt surrogate molecules alone and in combination with romosozumab. [Diagram 36] Figure 36 shows the levels of therapeutic molecules in serum as measured by ELISA. These data accompany the gene expression data presented in Table 4. [Figure 37-1] Figure 37 shows liver (A), small intestine (B), and colon (C) ratios to body weight following treatment with AAV-delivered Wnt surrogates. (**) p<0.01. For each graph, treatments shown from left to right correspond to the treatments in the legend shown from top to bottom. [Figure 37-2] Same as above. [Figure 38] Figures 38A-B show body weight (A) and liver-to-body weight ratio (B) following treatment with recombinantly produced Wnt surrogate proteins. (**) p<0.05. For each time point, treatments shown from left to right correspond to the treatments in the legend shown from top to bottom. [Figure 39-1] Figures 39A-39D show induction of proliferation markers in response to R2M3-26 and Rspo2 recombinant proteins. Hepatic Ki67 (A) and cyclin D1 (B) mRNA expression. Mean number of PCNA (C) or phosphohistone H3 (D) positive nuclei per 10x field after immunohistochemical staining with PCNA and phosphohistone H3 antibodies, respectively. (*) p<0.05, (**) p<0.01, (***) p<0.001, (****) p<0.0001. For each time point, treatments shown from left to right correspond to the treatments in the legend shown from top to bottom. [Figure 39-2] Same as above. [Figure 40-1]Figures 40A-40H show the efficacy of AAV-delivered Wnt surrogates and R-spondin in thioacetamide-induced chronic liver disease models. Design of study 1 (A) and study 2 (B). Liver-to-body weight ratio (C-D), liver weight (E-F), hepatic collagen A1 mRNA expression (G), and red area percentage in liver histological sections stained with Sirius Red (H) in response to AAV-delivered wnt surrogates and R-spondin in study 1 (C, E, G, and H) and study 2 (D, F, H). (*) p<0.05, (**) p<0.01, (***) p<0.001, (****) p<0.0001. For each graph, the treatments shown from left to right correspond to the treatments in the legend shown from top to bottom (not including baseline). [Figure 40-2] Same as above. [Figure 40-3] Same as above. [Figure 40-4] Same as above. [Figure 41-1] Figures 41A-41N show the efficacy of recombinantly produced Wnt surrogates and R-spondin in a thioacetamide-induced chronic liver disease model. Study design (A). D-2, D0, D3, D7, D10, D14 represent days from the start of treatment with recombinant proteins. Liver-to-body weight ratio (B,C), hepatic Axin 2 mRNA (D,E), Cyclin D1 mRNA (F,G), and Ki67 mRNA (H,I) expression, mean number of PCNA (J,K) or phosphohistone H3 (L,M) positive nuclei per 10x field after immunohistochemical staining with PCNA and phosphohistone H3 antibodies, respectively, in studies with Rspo2 alone (B,D,F,H,J,L) or R2M3-26 / Rspo2 combination treatment (C,E,G,I,K,M). Ratio of prothrombin time to the mean prothrombin time in plasma collected from control naive mice without TAA exposure (N). (*) p<0.05, (**) p<0.01, (****) p<0.0001. No TAA treatment is indicated by a dashed line. For each bar time point, treatments shown from left to right correspond to the treatments in the legend above, listed from top to bottom. [Figure 41-2] Same as above. [Figure 41-3] Same as above. [Figure 41-4] Same as above. [Figure 41-5] Same as above. [Figure 41-6] Same as above. [Figure 41-7] Same as above. [Figure 41-8] Same as above. [Figure 42-1] Figures 42A-42C show the efficacy of recombinantly produced Wnt surrogates and R-spondin in CCl4-induced chronic liver disease model. Study design (A). Liver-to-body weight ratio (B), prothrombin time (C), and Sirius red staining (D) in response to CCl4 treatment, R2M3-26, and Rspo2. (*) p<0.05, (**) p<0.01, (***) p<0.001, (****) p<0.0001. For each graph, the treatments shown from left to right correspond to the treatments in the legend shown from top to bottom (not including baseline). [Figure 42-2] Same as above. [Figure 42-3] Same as above. [Figure 42-4] Same as above. [Figure 43-1] Figures 43A-43D show induction of proliferation markers in response to recombinantly produced Wnt surrogates in an acetaminophen-induced acute liver injury model. Study design (A). Serum levels of alanine transferase 24 and 48 hours after treatment with acetaminophen (B). Relative cyclin D1 (C) and Ki67 (D) mRNA expression. (*) p<0.05, (**) p<0.001, (****) p<0.0001. [Figure 43-2] Same as above. [Figure 43-3] Same as above. [Figure 43-4] Same as above. [Figure 44-1]Figures 44A-44D show induction of proliferation markers in response to R-spondin in an acetaminophen-induced acute liver injury model. Study design (A). Serum levels of alanine transferase 24 and 48 hours after treatment with acetaminophen (B). Relative cyclin D1 (C) and Ki67 (D) mRNA expression. (*) p<0.01, (**) p<0.001, (****) p<0.0001. [Figure 44-2] Same as above. [Figure 44-3] Same as above. [Figure 44-4] Same as above. [Figure 45-1] Figures 45A-45D show induction of proliferation markers in response to Wnt surrogates and R-spondin in acetaminophen-induced acute liver injury model. Study design (A). Serum levels of alanine transferase (B) 24, 36, 48 and 60 hours after treatment with acetaminophen. Relative cyclin D1 (C) and Ki67 (D) mRNA expression. (*) p<0.05, (****) p<0.0001. For each time point, treatments shown from left to right correspond to treatments in the legend shown from top to bottom. [Figure 45-2] Same as above. [Figure 45-3] Same as above. [Figure 45-4] Same as above. [Figure 46-1] Figures 46A-46D show the efficacy of recombinantly produced Wnt surrogates and R-spondin on survival of mice after acetaminophen-induced liver injury. Study design (A). Survival curves of mice treated with control anti-eGFP control protein or R2M3-26 (B), Rspo2 (C), or a combination of R2M3-26 and Rspo2 (D) recombinant proteins. [Figure 46-2] Same as above. [Figure 46-3] Same as above. [Figure 46-4] Same as above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The present disclosure relates to Wnt surrogate molecules that bind to one or more Fzd receptors and one or more LRP5 or LRP6 receptors and regulate downstream Wnt signaling pathways. In certain embodiments, the Wnt surrogate molecules activate or increase signaling through the Wnt signaling pathway. In certain embodiments, the Wnt surrogate molecules disclosed herein include (i) one or more antibodies or antigen-binding fragments thereof that specifically bind to one or more Fzd receptors, including antibodies or antigen-binding fragments thereof with specific Fzd receptor specificity and / or functional properties, and (ii) one or more antibodies or antigen-binding fragments thereof that specifically bind to LRP5 and / or LRP6. Certain embodiments encompass specific structural formats or arrangements in the Fzd binding region(s) and LRP5 / 6 binding region(s) of the Wnt surrogate molecules that are advantageous for increasing Wnt pathway signaling and associated biological effects.

[0027] Embodiments of the present invention relate to the use of Wnt surrogate molecules for the diagnosis, evaluation, and treatment of diseases and disorders associated with the Wnt signaling pathway. In certain embodiments, the subject Wnt surrogate molecules are used to regulate the Wnt signaling pathway in cells or tissues. In certain embodiments, the subject Wnt surrogate molecules are used in the treatment or prevention of diseases and disorders associated with abnormal or deregulated (e.g., reduced) Wnt signaling, or in which regulating (e.g., increasing) Wnt signaling is believed to provide therapeutic benefit.

[0028] The practice of the present invention will employ, unless expressly indicated to the contrary, conventional methods of virology, immunology, microbiology, molecular biology, and recombinant DNA techniques within the skill of those in the art, many of which are described below for illustrative purposes. Such techniques are fully explained in the literature, see, for example, Current Protocols in Molecular Biology or Current Protocols in Immunology, John Wiley & Sons, New York, NY (2009); Ausubel et al., Short Protocols in Molecular Biology, 3 rd ed.,Wiley & Sons,1995;Sambrook and Russell,Molecular Cloning:A Laboratory Manual(3rd Edition,2001);Maniatis et al.Molecular Cloning:A Laboratory Manual(1982);DNA Cloning:A Practical Approach,vol.I & II(D.Glover,ed.);Oligonucleotide Synthesis(N.Gait,ed.,1984);Nucleic See Acid Hybridization (B. Hames & S. Higgins, eds., 1985); Transcription and Translation (B. Hames & S. Higgins, eds., 1984); Animal Cell Culture (R. Freshney, ed., 1986); Perbal, A Practical Guide to Molecular Cloning (1984) and other similar references.

[0029] As used in this specification and the appended claims, the singular forms "a / an" and "the" include plural referents unless the content clearly dictates otherwise.

[0030] Throughout this specification, unless the context requires otherwise, "comprise" or variations such as "comprises" or "comprising" should be understood to mean the inclusion of a stated element or integer, or group of elements or integers, but not the exclusion of any other element or integer, or group of elements or integers.

[0031] Each embodiment herein is intended to apply mutatis mutandis to every other embodiment unless otherwise stated.

[0032] Standard techniques may be used for recombinant DNA, oligonucleotide synthesis, and tissue culture and transformation (e.g., electroporation, lipofection). Enzymatic reactions and purification techniques may be performed according to manufacturer's specifications or as commonly accomplished in the art or as described herein. These and related techniques and procedures may generally be performed according to conventional methods well known in the art and as described in various general and more specific references cited and discussed throughout this specification. Unless specific definitions are provided, the nomenclature utilized in connection with molecular biology, analytical chemistry, synthetic organic chemistry, and medicinal and pharmaceutical chemistry described herein, as well as laboratory procedures and techniques in these fields, are those well known and commonly used in the art. Standard techniques may be used for recombinant technology, molecular biology, microbiology, chemical synthesis, chemical analysis, pharmaceutical preparation, formulation, and delivery, and treatment of subjects.

[0033] Embodiments of the present invention relate to antibodies and antigen-binding fragments thereof that bind to one or more Fzd receptors. Exemplary antibodies, or antigen-binding fragments thereof or complementarity determining regions (CDRs) thereof, are set forth in Tables 1A and 1B and SEQ ID NOs: 1-65 or 129-132 in Table 3. Anti-Fzd antibodies or antigen-binding fragments thereof that may be used or may be present in the Wnt surrogate molecules disclosed herein include, but are not limited to, those described in U.S. Provisional Patent Application No. 62 / 607,877, entitled "Anti-Frizzled Antibodies and Methods of Use" (Attorney Docket No. SRZN-004 / 00US, filed December 19, 2017).

[0034] Embodiments of the present invention relate to antibodies and antigen-binding fragments thereof that bind to LRP5 and / or LRP6. Exemplary antibodies, or antigen-binding fragments thereof or complementarity determining regions (CDRs) thereof, are set forth in Tables 2A and 2B and SEQ ID NOs: 66-88 or 133 in Table 3. Anti-LRP5 / 6 antibodies or antigen-binding fragments thereof that may be used or may be present in the Wnt surrogate molecules disclosed herein include, but are not limited to, those described in U.S. Provisional Patent Application No. 62 / 607,879, entitled "Anti-LRP5 / 6 Antibodies and Methods of Use" (Attorney Docket No. SRZN-005 / 00US, filed December 19, 2017).

[0035] As is well known in the art, an antibody is an immunoglobulin molecule capable of specifically binding to a target (e.g., carbohydrate, polynucleotide, lipid, polypeptide, etc.) via at least one epitope recognition site located within the variable region of the immunoglobulin molecule. As used herein, the term encompasses intact polyclonal or monoclonal antibodies, but also fragments thereof (e.g., dAb, Fab, Fab', F(ab')2, Fv), single chain (scFv), VHH or sdAb, synthetic variants thereof, natural variants, fusion proteins comprising an antibody or an antigen-binding fragment thereof, humanized antibodies, chimeric antibodies, and any other modified configuration of an immunoglobulin molecule that contains an antigen-binding site or fragment (epitope recognition site) with the required specificity. "Diabodies" or 2scFv-Ig antibodies, which are multivalent or multispecific fragments constructed by gene fusion (WO94 / 13804; P. Holliger et al., Proc. Natl. Acad. Sci. USA 90 6444-6448, 1993), are also a particular form of antibody contemplated herein. Minibodies comprising scFvs linked to a CH3 domain are also included herein (S. Hu et al., J. Immunol. 2002, 143: 1111-1115). et al., Cancer Res., 56, 3055-3061, 1996). For example, Ward,ESet al.,Nature 341,544-546(1989);Bird et al.,Science,242,423-426,1988;Huston et al.,PNAS USA,85,5879-5883,1988);PCT / US92 / 09965;WO94 / 13804;P.Holliger et al. See al., Proc. Natl. Acad. Sci. USA 90 6444-6448, 1993; Y. Reiter et al., Nature Biotech, 14, 1239-1245, 1996; S. Hu et al., Cancer Res., 56, 3055-3061, 1996.

[0036] The term "antigen-binding fragment" as used herein refers to a polypeptide fragment comprising at least one CDR of an immunoglobulin heavy and / or light chain, or a VHH or sdAb, that binds to an antigen of interest, in particular one or more Fzd receptors or LRP5 or LRP6 receptors. In this regard, an antigen-binding fragment of an antibody described herein can comprise one, two, three, four, five, or all six CDRs of the VH and VL sequences described herein from an antibody that binds to one or more Fzd receptors or LRP5 and / or LRP6. In certain embodiments, an antigen-binding fragment can comprise all three VH CDRs or all three VL CDRs. Similarly, the antigen-binding fragment can comprise all three CDRs of a VHH or sdAb. An antigen-binding fragment of an Fzd-specific antibody can bind to a Fzd receptor. An antigen-binding fragment of an LRP5 / 6-specific antibody can bind to an LRP5 and / or LRP6 receptor. As used herein, the term not only encompasses isolated fragments, but also encompasses polypeptides comprising an antigen-binding fragment of an antibody disclosed herein, such as fusion proteins comprising an antigen-binding fragment of an antibody disclosed herein, such as a fusion protein comprising a VHH or sdAb that binds one or more Fzd receptors and a VHH or sdAb that binds LRP5 and / or LRP6.

[0037] The term "antigen" refers to a molecule or a portion of a molecule that can be bound by a selective binding agent (e.g., an antibody) and that can be used in an animal to generate antibodies capable of binding to an epitope of that antigen. In certain embodiments, a binding agent (e.g., a Wnt surrogate molecule or binding region thereof) is said to specifically bind to an antigen if it preferentially recognizes a target antigen within a complex mixture of proteins and / or macromolecules. In certain embodiments, a Wnt surrogate molecule or binding region thereof (e.g., an antibody or antigen-binding fragment thereof) has an equilibrium dissociation constant of ≦10 -7 or ≦10 -8An antigen is said to specifically bind when M. In some embodiments, the equilibrium dissociation constant is ≦10 -9 M or ≦10 -10 It can be M.

[0038] In certain embodiments, the antibodies and antigen-binding fragments thereof described herein comprise a set of heavy and light chain CDRs, which are present between a set of framework regions (FRs) of the heavy and light chains, respectively. The set of FRs supports the CDRs and defines their spatial relationship to each other. As used herein, the term "set of CDRs" refers to the three hypervariable regions of the V region of the heavy or light chain. These regions are designated as "CDR1", "CDR2", and "CDR3" proceeding from the N-terminus of the heavy or light chain, respectively. Thus, an antigen-binding site comprises six CDRs, including the set of CDRs from each of the V regions of the heavy and light chains. A polypeptide comprising a single CDR (e.g., CDR1, CDR2, or CDR3) is referred to herein as a "molecular recognition unit". Crystallographic analysis of multiple antigen-antibody complexes has demonstrated that amino acid residues of the CDRs form extensive contacts with bound antigen, with the most extensive antigen contacts being contacts made by the heavy chain CDR3. Thus, the molecular recognition unit is primarily responsible for the specificity of the antigen-binding site.

[0039] As used herein, the term "FR set" refers to four adjacent amino acid sequences that frame the CDRs of a CDR set of a heavy or light chain V region. Although some FR residues may contact the bound antigen, FRs are primarily responsible for folding the V region into the antigen binding site, specifically the FR residues directly adjacent to the CDRs. Within the FRs, certain amino acid residues and certain structural features are highly conserved. In this respect, all V region sequences contain an internal disulfide loop of approximately 90 amino acid residues. When the V region folds into the binding site, the CDRs are presented as protruding loop motifs that form the antigen binding surface. In general, regardless of the detailed CDR amino acid sequence, it is recognized that there are conserved structural regions of the FRs that influence the folded shape of the CDR loops to be in a certain "canonical" structure. In addition, certain FR residues are known to participate in non-covalent interdomain contacts that stabilize the interaction of the heavy and light chains of an antibody.

[0040] The structure and location of the CDRs and variable domains of immunoglobulins can be determined by reference to Kabat, EA et al., Sequences of Proteins of Immunological Interest. 4th Edition. US Department of Health and Human Services. 1987 and updates thereto (available on the Internet at immuno.bme.nwu.edu). Alternatively, CDRs can be determined by using IMGT® (International ImMunoGeneTics Information System®), available at http: / / www.imgt.org (see, e.g., Lefranc, M.-P. et al. (1999) Nucleic Acids Res., 27:209-212; Ruiz, M. et al. (2000) Nucleic Acids Res., 28:219-221; Lefranc, M.-P. (2001) Nucleic Acids Res., 29:207-209; Lefranc, M.-P. (2003) Nucleic Acids Res., 31:307-310; Lefranc, M.-P. et al. (2004) In Silico Biol.,5,0006[Epub],5:45-60(2005)];Lefranc,M.-P.et al.(2005)Nucleic Acids Res.,33:D593-597;Lefranc,M.-P.et al.(2009)Nucleic Acids Res.,37:D1006-1012;Lefranc,M.-P.et al. (2015) Nucleic Acids Res., 43:D413-422).

[0041] "Monoclonal antibody" refers to a homogenous antibody population composed of amino acids (natural or non-natural) involved in selective binding of an epitope. Monoclonal antibodies are highly specific and directed to a single epitope. The term "monoclonal antibody" encompasses intact and full-length monoclonal antibodies, as well as fragments thereof (e.g., Fab, Fab', F(ab')2, Fv), single chain (scFv), VHH or sdAb, variants thereof, fusion proteins comprising an antigen-binding fragment of a monoclonal antibody, humanized monoclonal antibodies, chimeric monoclonal antibodies, and any other modified configuration of an immunoglobulin molecule comprising an antigen-binding fragment (epitope recognition site) with the required specificity and ability to bind to the epitope, including the Wnt surrogate molecules disclosed herein. It is not intended to be limiting as to the source of the antibody or the manner in which the antibody is made (e.g., hybridoma, phage selection, recombinant expression, transgenic animals, etc.). The term includes whole immunoglobulins as well as fragments such as those explained above in the definition of "antibody."

[0042] The proteolytic enzyme papain preferentially cleaves IgG molecules to produce several fragments, two of which (F(ab) fragments) each contain a covalently linked heterodimer with an intact antigen-binding site. The enzyme pepsin can cleave IgG molecules to produce several fragments, including F(ab')2, which contains both antigen-binding sites. Fv fragments for use in accordance with certain embodiments of the invention can be produced by preferential proteolytic cleavage of IgM immunoglobulin molecules, and in rare cases, of IgG or IgA immunoglobulin molecules. However, Fv fragments are more commonly derived using recombinant techniques known in the art. Fv fragments are non-covalent V fragments that contain an antigen-binding site that retain much of the antigen recognition and binding capacity of the native antibody molecule. H ::V LHeterodimers are included. Inbar et al. (1972) Proc. Nat. Acad. Sci. USA 69:2659-2662; Hochman et al. (1976) Biochem 15:2706-2710; and Ehrlich et al. (1980) Biochem 19:4091-4096.

[0043] In certain embodiments, single chain Fv antibodies, i.e., scFv antibodies, are contemplated, such as kappa bodies (Ill et al., Prot. Eng. 10:949-57 (1997); minibodies (Martin et al., EMBO J 13:5305-9 (1994); diabodies (Holliger et al., PNAS 90:6444-8 (1993); or Janusins ​​(Traunecker et al., EMBO J 10:3655-59 (1991) and Traunecker et al., Int. J. Cancer 1999). Suppl. 7:51-52 (1992)) can be prepared using standard molecular biology techniques following the teachings of the present application for selection of antibodies with the desired specificity. In yet other embodiments, bispecific or chimeric antibodies can be made that encompass the ligands of the present disclosure. For example, chimeric antibodies can include CDRs and framework regions from different antibodies, while generating bispecific antibodies that specifically bind to one or more Fzd receptors through one binding domain and to a second molecule through a second binding domain. These antibodies can be produced through recombinant molecular biology techniques or can be physically conjugated together.

[0044] Single-chain antibody Fv (scFv) polypeptides are composed of V H - and V L -Covalently linked V, expressed from a gene fusion containing the coding gene H ::V LIt is a heterodimer. Huston et al. (1988) Proc. Nat. Acad. Sci. USA 85(16):5879-5883. Several methods have been described to identify chemical structures for converting naturally aggregated (but chemically separated) polypeptide light and heavy chains from antibody V regions into scFv molecules that fold into a three-dimensional structure substantially similar to the structure of an antigen-binding site. See, for example, U.S. Patent Nos. 5,091,513 and 5,132,405 to Huston et al., and U.S. Patent No. 4,946,778 to Ladner et al.

[0045] In certain embodiments, the antibodies described herein are in the form of diabodies. Diabodies are multimers of polypeptides, each of which comprises a first domain comprising a binding region of an immunoglobulin light chain and a second domain comprising a binding region of an immunoglobulin heavy chain, the two domains being linked (e.g., by a peptide linker) but unable to associate with each other to form an antigen-binding site. The antigen-binding site is formed by the association of a first domain of one polypeptide in the multimer with a second domain of another polypeptide in the multimer (WO94 / 13804).

[0046] A dAb fragment of an antibody consists of the VH domain (Ward, ES et al., Nature 341, 544-546 (1989)).

[0047] When bispecific antibodies are used, they can be identified by a variety of methods (Holliger, P. and The bispecific antibody may be a conventional bispecific antibody that can be produced (e.g., prepared chemically or from a hybrid hybridoma) by conventional techniques (Winter G. Current Opinion Biotechnol. 4, 446-449 (1993)) or any of the bispecific antibody fragments described above. Diabodies and scFvs can be constructed without an Fc region, using only variable domains, potentially reducing the effects of anti-idiotypic reaction.

[0048] Bispecific diabodies may also be particularly useful because, in contrast to bispecific whole antibodies, they can be easily constructed and expressed in E. coli. Diabodies (and many other polypeptides, such as antibody fragments) of appropriate binding specificity can be easily selected from libraries using phage display (WO94 / 13804). If one arm of the diabody is kept constant, for example with respect to specificity directed against antigen X, a library can be generated in which the other arm is varied and an antibody of appropriate specificity is selected. Bispecific whole antibodies can be generated by knobs-into-holes engineering (JBB Rodgeway et al., Protein Eng., 9, 616-621, 1996).

[0049] In certain embodiments, the antibodies described herein can be provided in the form of a UniBody®. A UniBody® is an IgG4 antibody with the hinge region removed (see GenMab Utrecht, The Netherlands; see also, for example, US20090226421). This unique antibody technology creates a smaller, more stable antibody format with a longer predicted therapeutic window than current small antibody formats. IgG4 antibodies are considered inert and therefore do not interact with the immune system. Fully human IgG4 antibodies can be modified by removing the hinge region of the antibody, resulting in half-molecule fragments with different stability characteristics relative to the corresponding intact IgG4 (GenMab, Utrecht). Having an IgG4 molecule leaves only one area on the UniBody® that can bind to the cognate antigen (e.g., disease target), so the UniBody® binds monovalently to only one site on the target cell.

[0050] In certain embodiments, the antibodies of the present disclosure can take the form of a VHH or sdAb. Originally, VHH or sdAb technology was developed after the discovery and identification of Camelidae (e.g., camels and llamas) as possessing fully functional antibodies that consist only of heavy chains and lack light chains. Such heavy chain-only antibodies contain a single variable domain (V HH ) and two constant domains (C H 2. C H 3). The cloned and isolated single variable domains have full antigen-binding capacity and are highly stable. These single variable domains form the basis of "VHHs or sdAbs" due to their unique structural and functional properties. VHHs or sdAbs are encoded by a single gene and are efficiently produced in almost all prokaryotic and eukaryotic hosts, for example in E. coli (see, for example, U.S. Pat. No. 6,765,087), molds (e.g., Aspergillus or Trichoderma), and yeasts (e.g., Saccharomyces, Kluyveromyces, Hansenula, or Pichia) (see, for example, U.S. Pat. No. 6,838,254). The production process is scalable and multi-kilogram quantities of VHHs or sdAbs have been produced. VHHs or sdAbs can be formulated as a ready-to-use solution with a long shelf life. The VHH or sdAb method (see, for example, WO06 / 079372) is a unique method for generating VHH or sdAbs against desired targets, which is based on automated high-throughput selection of B cells. VHH or sdAbs are single domain antigen-binding fragments of heavy chain-only antibodies specific to camelids. The size of VHH antibodies or sdAbs is typically small, around 15 kDa.

[0051] In certain embodiments, the antibodies or antigen-binding fragments thereof disclosed herein are humanized. This refers to chimeric molecules, which are generally prepared using recombinant techniques, that have an antigen-binding site derived from an immunoglobulin from a non-human species, with the remaining immunoglobulin structure of the molecule based on the structure and / or sequence of a human immunoglobulin. The antigen-binding site may comprise either a complete variable domain fused with a constant domain, or only the CDRs grafted into the appropriate framework regions in the variable domain. The epitope-binding site may be wild-type or modified by one or more amino acid substitutions. This removes the constant regions as immunogens in human individuals, but the possibility of an immune response to the external variable regions remains (LoBuglio, AF et al., (1989) Proc Natl Acad Sci USA 86:4220-4224; Queen et al., PNAS (1988) 86:10029-10033; Riechmann et al., Nature (1988) 332:323-327). Exemplary methods for humanizing the anti-Fzd antibodies disclosed herein include those described in U.S. Pat. No. 7,462,697.

[0052] Another approach focuses on not only providing constant regions of human origin, but also modifying the variable regions to reshape them as close to the human form as possible. Both the heavy and light chain variable regions are known to contain three complementarity determining regions (CDRs). The CDRs vary in response to the epitope in question, determining the binding capacity, and are flanked by four framework regions (FRs). The FRs are relatively conserved in a given species and are presumed to provide a scaffold for the CDRs. When a non-human antibody is prepared against a specific epitope, the variable region can be "reshaped" or "humanized" by grafting the CDRs from the non-human antibody onto the FRs present in the human antibody to be modified. Application of this approach to various antibodies has been reported in the following publications: Sato, K., et al., (1993) Cancer Res 53:851-856; Riechmann, L., et al., (1988) Nature 332:323-327; Verhoeyen, M., et al., (1988) Science 239:1534-1536; Kettleborough, CA, et al., (1991) Protein Engineering 4:773-3783; Maeda, H., et al., (1991) Human Antibodies Hybridoma 2:124-134; Gorman, SD, et al., (1991) Proc Natl Acad Sci USA 88:4181-4185; Tempest, PR, et al., (1991) Bio / Technology 9:266-271; Co, MS, et al., (1991) Proc Natl Acad Sci USA 88:2869-2873; Carter, P., et al., (1992) Proc Natl Acad Sci USA 89:4285-4289; and Co, MS et al., (1992) J Immunol 148:1149-1154. In some embodiments, the humanized antibody preserves all CDR sequences (e.g., a humanized mouse antibody that contains all six CDRs from the mouse antibodies).In other embodiments, a humanized antibody has one or more (1, 2, 3, 4, 5, 6) CDRs that are altered relative to the original antibody, also referred to as one or more CDRs "derived from" one or more CDRs from the original antibody.

[0053] In certain embodiments, the antibody of the present disclosure may be a chimeric antibody. In this regard, a chimeric antibody is composed of an antigen-binding fragment of an antibody operably linked or fused with a heterologous Fc portion of a different antibody. In certain embodiments, the heterologous Fc domain is of human origin. In other embodiments, the heterologous Fc domain may be from a different Ig class from a patient antibody, including IgA (including subclasses IgA1 and IgA2), IgD, IgE, IgG (including subclasses IgG1, IgG2, IgG3, and IgG4), and IgM. In further embodiments, the heterologous Fc domain may be composed of CH2 and CH3 domains from one or more different Ig classes. As discussed above for humanized antibodies, an antigen-binding fragment of a chimeric antibody may include only one or more of the CDRs of an antibody described herein (e.g., one, two, three, four, five, or six CDRs of an antibody described herein) or may include the entire variable domain (VL, VH, or both).

[0054] Wnt surrogates In certain aspects, the present disclosure provides a Wnt surrogate molecule that binds to one or more Fzd receptors and one or both of LRP5 and / or LRP6. Wnt surrogate molecules may also be referred to as "Wnt surrogates" or "Wnt mimetics." In certain embodiments, the Wnt surrogate molecule binds to one or more human Fzd receptors and one or both of human LRP5 and / or human LRP6.

[0055] In certain embodiments, Wnt surrogate molecule can regulate or regulate the Wnt signaling events in cells that contact with Wnt surrogate molecule.In certain embodiments, Wnt surrogate molecule increases Wnt signaling, for example, through canonical Wnt / β-catenin pathway.In certain embodiments, Wnt surrogate molecule specifically regulates the biological activity of human Wnt signaling pathway.

[0056] The Wnt surrogate molecules of the present invention are biologically active in binding to one or more Fzd receptors and one or more of LRP5 and LRP6 and in activating Wnt signaling, i.e., the Wnt surrogate molecules are Wnt agonists. The term "Wnt agonist activity" refers to the ability of an agonist to mimic the effect or activity of binding to frizzled proteins and / or LRP5 or LRP6 on Wnt proteins. The ability of the Wnt surrogate molecules and other Wnt agonists disclosed herein to mimic Wnt activity can be confirmed by multiple assays. Wnt agonists typically initiate a similar or identical reaction or activity to that initiated by the natural ligand of the receptor. In particular, the Wnt agonists disclosed herein enhance or increase the canonical Wnt / β-catenin signaling pathway. As used herein, the term "enhance" refers to a measurable increase in the level of Wnt / β-catenin signaling compared to the level in the absence of a Wnt agonist (e.g., a Wnt surrogate molecule disclosed herein). In certain embodiments, the increase in the level of Wnt / β-catenin signaling is at least 10%, at least 20%, at least 50%, at least 2-fold, at least 5-fold, at least 10-fold, at least 20-fold, at least 50-fold, or at least 100-fold compared to the level of Wnt / β-catenin signaling in the absence of a Wnt agonist (e.g., of the same cell type). Methods for measuring Wnt / β-catenin signaling are known in the art and include those described herein.

[0057] In certain embodiments, the Wnt surrogate molecules disclosed herein are bispecific, i.e., they specifically bind to two or more different epitopes (e.g., one or more Fzd receptors and LRP5 and / or LRP6).

[0058] In certain embodiments, the Wnt surrogate molecules disclosed herein are multivalent, e.g., comprise two or more regions that each specifically bind to the same epitope (e.g., two or more regions that bind to an epitope in one or more Fzd receptors and / or two or more regions that bind to an epitope in LRP5 and / or LRP6). In certain embodiments, the Wnt surrogate molecules comprise two or more regions that bind to an epitope in one or more Fzd receptors and two or more regions that bind to an epitope in LRP5 and / or LRP6. In certain embodiments, a Wnt surrogate molecule comprises a ratio of about 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 2:3, 2:5, 2:7, 7:2, 5:2, 3:2, 3:4, 3:5, 3:7, 3:8, 8:3, 7:3, 5:3, 4:3, 4:5, 4:7, 4:9, 9:4, 7:4, 5:4, 6:7, 7:6, 1:2, 1:3, 1:4, 1:5, or 1:6. In certain embodiments, a Wnt surrogate molecule is bispecific and multivalent.

[0059] The Wnt surrogate molecules disclosed herein can have any of a variety of different structural formats or configurations. A Wnt surrogate molecule can include a polypeptide and / or a non-polypeptide binding moiety (e.g., a small molecule). In certain embodiments, a Wnt surrogate molecule includes both a polypeptide region and a non-polypeptide binding moiety. In certain embodiments, a Wnt surrogate molecule can have a single polypeptide or can have two or more, three or more, or four or more polypeptides. In certain embodiments, one or more polypeptides of a Wnt surrogate molecule is an antibody or antigen-binding fragment thereof. In certain embodiments, a Wnt surrogate includes two antibodies or antigen-binding fragments thereof, one that binds to one or more Fzds and one that binds to LRP5 and / or LRP6. In certain embodiments, a Wnt surrogate includes one, two, three, or four polypeptides, for example, linked or bound to each other or fused to each other.

[0060] When the Wnt surrogate molecule comprises a single polypeptide, it can be a fusion protein comprising one or more Fzd binding domains and one or more LRP5 / 6 binding domains, which may be directly fused or connected via a linker, such as a polypeptide linker, including but not limited to any of those disclosed herein.

[0061] When a Wnt surrogate molecule comprises two or more polypeptides, the polypeptides may be linked via covalent bonds (e.g., disulfide bonds) and / or non-covalent interactions. For example, the heavy chains of human immunoglobulin IgG interact directly at the level of their CH3 domains and at the level of their CH2 domains through carbohydrate attached to asparagine (Asn) N84.4 of the DE turn. In certain embodiments, a Wnt surrogate molecule comprises one or more regions derived from an antibody or an antigen-binding fragment thereof, such as an antibody heavy chain or an antibody light chain or a fragment thereof. In certain embodiments, a Wnt surrogate polypeptide comprises two heavy chain regions (e.g., hinge regions) linked together via one or more disulfide bonds. In certain embodiments, a Wnt surrogate polypeptide comprises an antibody light chain region (e.g., C) linked together via one or more disulfide bonds. L region) and antibody heavy chain regions (e.g., C H 1 area).

[0062] Wnt surrogate polypeptides may be engineered to facilitate binding between two polypeptides. For example, knobs-into-holes amino acid modifications can be introduced into two different polypeptides to facilitate their binding. Knobs-into-holes amino acid (AA) changes are a rational design strategy developed in antibody engineering and are used for heavy chain heterodimerization in the production of bispecific IgG antibodies. AA changes are engineered to create a knob in the CH3 of the heavy chain of the first antibody and a hole in the CH3 of the heavy chain of the second antibody. The knob can be represented by tyrosine (Y), which belongs to the "very large" IMGT volume class of AA, and the hole can be represented by threonine (T), which belongs to the "small" IMGT volume class. Other methods of introducing modifications into polypeptides to facilitate their binding are known and available in the art. For example, specific amino acids can be introduced and used for cross-linking, such as cysteine ​​to form intermolecular disulfide bonds.

[0063] Wnt surrogate molecules can have a variety of different structural formats, including, but not limited to, those shown in FIG.

[0064] In one embodiment, the Wnt surrogate molecule comprises an scFv or an antigen-binding fragment thereof fused to a VHH or sdAb or an antigen-binding fragment thereof. In certain embodiments, the scFv specifically binds one or more Fzd receptors and the VHH or sdAb specifically binds LRP5 and / or LRP6. In certain embodiments, the scFv specifically binds LRP5 and / or LRP6 and the VHH or sdAb specifically binds one or more Fzd receptors. In certain embodiments, the scFv or an antigen-binding fragment thereof is fused directly to the VHH or sdAb or an antigen-binding fragment thereof, and in other embodiments, the two binding regions are fused via a linker moiety. In certain embodiments, the VHH or sdAb is fused to the N-terminus of the scFv and in other embodiments, the VHH or sdAb is fused to the C-terminus of the scFv. In certain embodiments, the scFv comprises any set of CDRs described herein or described herein. In certain embodiments, the VHH or sdAb comprises any set of CDRs described or disclosed herein.

[0065] In various embodiments (including but not limited to those shown in FIG. 1A ), the Wnt surrogate molecule comprises one or more Fabs or antigen-binding fragments thereof and one or more VHHs or sdAbs or antigen-binding fragments thereof (or alternatively, one or more scFvs or antigen-binding fragments thereof). In certain embodiments, the Fabs specifically bind one or more Fzd receptors and the VHHs or sdAbs (or scFvs) specifically bind LRP5 and / or LRP6. In certain embodiments, the Fabs specifically bind LRP5 and / or LRP6 and the VHHs or sdAbs (or scFvs) specifically bind one or more Fzd receptors. In certain embodiments, the VHHs or sdAbs (or scFvs) are fused to the N-terminus of the Fab, and in some embodiments, the VHHs or sdAbs (or scFs) are fused to the C-terminus of the Fab. In certain embodiments, the Fab is present in an all-IgG format and the VHH or sdAb (or scFv) is fused to the N-terminus and / or C-terminus of the IgG light chain. In certain embodiments, the Fab is present in an all-IgG format and the VHH or sdAb (or scFv) is fused to the N-terminus and / or C-terminus of the IgG heavy chain. In certain embodiments, two or more VHH or sdAb (or scFv) are fused to the IgG in any combination of these positions.

[0066] Fab can be converted to a full IgG format containing both Fab and Fc fragments, for example, genetic engineering can be used to generate a fusion polypeptide containing a Fab fused to an Fc region (i.e., the Fab is present in the full IgG format). The Fc region in the full IgG format can be derived from any of a variety of different Fcs, including, but not limited to, wild-type or modified IgG1, IgG2, IgG3, IgG4, or other isotypes, such as wild-type or modified human IgG1, human IgG2, human IgG3, human IgG4, human IgG4Pro (containing a mutation in the core hinge region that prevents the formation of IgG4 half molecules), human IgA, human IgE, human IgM, or a modified IgG1 called IgG1 LALAPG. The L235A, P329G (LALA-PG) variant has been shown in both mouse IgG2a and human IgG1 to ablate Fc-gamma-dependent antibody-dependent cell-mediated cytotoxicity (ADCC), in addition to ablation of complement binding and fixation. Such LALA-PG substitutions allow for a more accurate translation of results generated by "effector-less" antibody framework scaffolds between mice and primates. In certain embodiments of any of the IgGs disclosed herein, the IgG comprises one or more of the following amino acid substitutions: N297G, N297A, N297E, L234A, L235A, or P236G.

[0067] Non-limiting examples of bivalent and bispecific Wnt surrogate molecules that are bivalent for both one or more Fzd receptors and LRP5 and / or LRP6 are shown as the top four structures illustrated in FIG. 1A, with VHH or sdAb or scFv illustrated in white and Fab or IgG illustrated in black. As shown, VHH or sdAb (or scFv) can be fused to the N-terminus of both light chains, the N-terminus of both heavy chains, the C-terminus of both light chains, or the C-terminus of both heavy chains. It is further contemplated that, for example, VHH or sdAb (or scFv) can be fused to both the N-terminus and C-terminus of the heavy and / or light chains, the N-terminus of the light chain and the C-terminus of the heavy chain, the N-terminus of the heavy chain and the C-terminus of the light chain, or the C-terminus of the heavy chain and the N-terminus of the light chain. In other related embodiments, two or more VHHs or sdAbs (or scFvs) may be fused together, optionally via a linker moiety, or fused to a Fab or IgG at one or more of these positions. In related embodiments, the Wnt surrogate molecule has a hetero-IgG format, where the Fab is present as a half antibody, and one or more VHHs or sdAbs (or scFvs) are fused to one or more of the N-terminus of the Fc, the N-terminus of the Fab, the C-terminus of the Fc, or the C-terminus of the Fab. A bispecific but monovalent version of this format is illustrated at the bottom of FIG. 1A. In certain embodiments, the Fab or antigen-binding fragment thereof (or IgG) is fused directly to the VHH or sdAb (or scFv) or antigen-binding fragment thereof, and in other embodiments, the binding regions are fused via a linker moiety. In certain embodiments, the Fab comprises any set of CDRs described herein or described herein. In certain embodiments, the VHH or sdAb or scFv comprises any set of CDRs described herein or disclosed herein.

[0068] In various embodiments (including but not limited to those shown in FIG. 1B), the Wnt surrogate molecule comprises one or more Fabs or antigen-binding fragments thereof that bind one or more Fzd receptors and one or more Fabs or antigen-binding fragments thereof that bind LRP5 and / or LRP6. In certain embodiments, the Wnt surrogate molecule comprises two Fabs or antigen-binding fragments thereof that bind one or more Fzd receptors and / or two Fabs or antigen-binding fragments thereof that bind LRP5 and / or LRP6. In certain embodiments, one or more of the Fabs are present in an all-IgG format, and in certain embodiments, both Fabs are present in an all-IgG format. In certain embodiments, the Fab in the all-IgG format specifically binds one or more Fzd receptors and the other Fab specifically binds LRP5 and / or LRP6. In certain embodiments, the Fabs specifically bind one or more Fzd receptors and the Fab in the all-IgG format specifically binds LRP5 and / or LRP6. In certain embodiments, the Fab specifically binds LRP5 and / or LRP6, and the Fab in the full IgG format specifically binds one or more Fzd receptors. In certain embodiments, the Fab is fused to the N-terminus of the IgG (e.g., the N-terminus of the heavy or light chain), optionally via a linker. In certain embodiments, the Fab is fused to the N-terminus of the IgG heavy chain and not to the light chain. In certain embodiments, the two heavy chains may be fused together, either directly or via a linker. An example of such a bispecific and bivalent for both receptors is shown at the top of FIG. 1B. In other related embodiments, two or more VHHs or sdAbs may be fused together, optionally via a linker moiety, or fused to the Fab or IgG at one or more of these positions. In related embodiments, the Wnt surrogate molecule has a hetero-IgG format, where one Fab is present as a half antibody and the other Fab is fused to one or more of the N-terminus of the Fc, the N-terminus of the Fab, or the C-terminus of the Fc. A bispecific but monovalent version of this format is illustrated at the bottom of FIG. 1B.In certain embodiments, a Fab or antigen-binding fragment thereof is fused directly to the other Fab or IgG or antigen-binding fragment thereof, while in other embodiments the binding regions are fused via a linker moiety. In certain embodiments, one or both of the two Fabs comprise any set of CDRs described herein or described herein.

[0069] In certain embodiments, the Wnt surrogate molecule has a format described in PCT Publication No. WO2017 / 136820, such as the Fabs-in-tandem IgG (FIT-IG) format (Shiyong Gong, Fang Ren, Danqing Wu, Xuan Wu & Chengbin Wu (2017)). FIT-IG also includes the format disclosed in "Fabs-in-tandem immunoglobulin is a novel and versatile bispecific design for engaging multiple therapeutic targets" mAbs, 9:7, 1118-1128, DOI:10.1080 / 19420862.2017.1345401. In certain embodiments, FIT-IG combines the functions of two antibodies into one molecule by rearranging the DNA sequences of two parent monoclonal antibodies into two or three constructs and co-expressing them in mammalian cells. Examples of FIT-IG formats and constructs are shown in PCT Publication No. WO2017 / 136820, Figures 1A and 1B and 2A and 2B. In certain embodiments, FIT-IG does not require Fc mutations, scFv elements, linkers or peptide connectors. The Fab domains of each arm work "in tandem" to form a tetravalent bispecific antibody with four active and independent antigen binding sites that retain the biological function of the parent antibody. In certain embodiments, the Wnt surrogate comprises a Fab and an IgG. In certain embodiments, the Fab binder LC is fused to the IgG HC, for example, by an intervening linker of various lengths. In various embodiments, the Fab binder HC may or may not be fused to the IgG LC. A variation of this format is called tandem Fab IgG (or FIT-Ig).

[0070] In certain embodiments, the Wnt surrogate molecule comprises two or more VHHs or sdAbs (or scFvs), including at least one VHH or sdAb (or scFv) that binds to one or more Fzd receptors and at least one VHH or sdAb (or scFv) that binds to LRP5 and / or LRP6. In certain embodiments, one of the binding regions is a VHH or sdAb and the other is a scFv. Wnt mimetic molecules comprising two or more VHHs or sdAbs (or scFvs) can be formatted in various configurations, including but not limited to those illustrated in FIG. 1C. In certain bispecific bivalent formats, two or more VHHs or sdAbs (or scFvs) are fused in tandem or to two different ends of Fc, optionally via one or more linkers. If a linker is present, the linker and its length may be the same or different between a VHH or sdAb (or scFv) and another VHH or sdAb (or scFv), or between a VHH or sdAb and an Fc. For example, in certain embodiments, a VHH or sdAb is fused to the N-terminus and / or C-terminus of an IgG heavy chain. In certain embodiments, two or more VHHs or sdAbs are fused to an IgG at any combination of these positions. Non-limiting examples of this type of bivalent bispecific Wnt surrogate molecule are illustrated as the top seven structures in FIG. 1C, where the first VHH or sdAb is illustrated in white, the Fc or IgG is illustrated in black, and the second VHH or sdAb is illustrated in light grey. In various embodiments, both VHHs or sdAbs may be fused to the N-terminus of Fc, the C-terminus of Fc, or one or more VHHs or sdAbs may be fused to either or both of the N-terminus or C-terminus of Fc. In a related embodiment, the Wnt surrogate molecule has a hetero-IgG format, where one VHH or sdAb is present as a half antibody and the other is fused to the N-terminus of Fc or the C-terminus of Fc. A bispecific but monovalent version of this format for each receptor is illustrated at the bottom of Figure 1C.In certain embodiments, a VHH or sdAb is directly fused to another VHH or sdAb, while in other embodiments, the binding region is fused via a linker moiety. In certain embodiments, the VHH or sdAb is described herein or comprises any set of CDRs described herein. In various embodiments, any of these formats can comprise one or more scFvs in place of one or more VHHs or sdAbs.

[0071] In certain embodiments, the Wnt surrogate molecule is formatted as a diabody. As shown in FIG. 1D, the binding agents for Fzd and LRP may be linked together in a diabody (or DART) configuration. The diabody may also be in a single chain configuration. If the diabody is fused to Fc, this creates a bivalent bispecific format. Without the fusion to Fc, this is a monovalent bispecific format. In certain embodiments, the diabody is a non-covalent dimeric scFv fragment consisting of a heavy chain variable (VH) region and a light chain variable (VL) region connected by a small peptide linker. Another form of diabody is the single chain (Fv)2, in which two scFv fragments are covalently linked to each other.

[0072] As discussed, the Wnt surrogate molecule, in various embodiments, comprises one or more antibodies or antigen-binding fragments thereof disclosed herein. Thus, in certain embodiments, the Wnt surrogate comprises two polypeptides, each polypeptide comprising a Nab or scFv that binds to LRP5 / 6 and a Nab or scFv that binds to one or more Wnts, optionally one of the binding domains being a scFv and the other being a Nab. In certain embodiments, the Wnt surrogate comprises three polypeptides, a first polypeptide comprising an antibody heavy chain, a second polypeptide comprising an antibody light chain, the antibody heavy and light chains binding to LRP5 / 6 or one or more Fzds, and a third polypeptide comprising a VHH or sdAb fused to a heavy chain Fc region, the VHH or sdAb binding to either LRP5 / 6 or one or more Fzds. In other embodiments, the Wnt polypeptide comprises four polypeptides, including two heavy chain polypeptides and two light chain polypeptides, where the two heavy chains and two light chains bind to LRP5 / 6 or one or more Fzds, and further comprises one or more Nabs or scFvs fused to one or more of the heavy and / or light chains, where the Nabs or scFvs bind to LRP5 / 6 or one or more Fzds. In another exemplary embodiment, the Wnt surrogate comprises at least four polypeptides, including two heavy chain polypeptides and two light chain polypeptides that bind to either LRP5 / 6 or one or more Fzds, and the Wnt surrogate further comprises a Fab that binds to LRP5 / 6 or one or more Fzds. For example, a Fab can include two polypeptides, each fused to one of two heavy chain polypeptides, and two polypeptides, each fused to one of two light chain polypeptides, or a Fab can include two polypeptides fused to one of two heavy chain polypeptides and two additional polypeptides, each binding to one of the two polypeptides fused to the heavy chain polypeptide to form a second Fab. Other configurations can also be used to produce the Wnt surrogates disclosed herein.

[0073] In certain embodiments, the Wnt surrogate molecule comprises a Fzd binding region (e.g., an anti-Fzd antibody) or an antigen-binding fragment thereof fused or conjugated to a polypeptide that specifically binds to one or more Fzd receptors. In certain embodiments, the polypeptide that specifically binds to one or more Fzd receptors is an antibody or an antigen-binding fragment thereof. In certain embodiments, this is an antibody or an antigen-binding fragment thereof disclosed herein or disclosed in U.S. Provisional Patent Application No. 62 / 607,877, entitled "Anti-Frizzled antibodies and Methods of Use", filed December 19, 2017, Attorney Docket No. SRZN-004 / 00US, which application is incorporated herein by reference in its entirety. In certain embodiments, the Fzd binding domain comprises three heavy chain CDRs and / or three light chain CDRs disclosed for any of the exemplary antibodies or fragments thereof that bind to one or more Fzd receptors shown in Table 1A. In certain embodiments, the Fzd binding domain comprises the three heavy chain CDRs and / or the three light chain CDRs disclosed for any of the exemplary antibodies or fragments thereof that bind to one or more Fzd receptors shown in Table 1A, which CDRs collectively comprise one, two, three, four, five, six, seven, or eight amino acid modifications (e.g., substitutions, deletions, or additions). In certain embodiments, the Fzd binding domain is a VHH or sdAb or is derived from a VHH or sdAb, such that Table 1A comprises only the three heavy chain CDRs. In certain embodiments, the Fzd binding domain comprises the three CDR HC sequences or variants shown in Table 1A, which CDRs collectively comprise one, two, three, four, five, six, seven, or eight amino acid modifications. In certain embodiments, the Fzd binding domain comprises a heavy chain fragment and / or a light chain fragment of any exemplary antibody or fragment thereof (or any antigen-binding fragment or variant) that binds to one or more Fzd receptors set forth in Table 1B or SEQ ID NOs:1-65 or 129-132.In certain embodiments, the Fzd binding domain is a Fab or is derived from a Fab, such that the heavy chains of Table 1B comprise a VH and a CH1 sequence but no CH2 or CH3 sequence. In certain embodiments, the Fzd binding domain is a VHH or sdAb or is derived from a VHH or sdAb, such that Table 1B comprises a VHH domain. In certain embodiments, the Fzd binding region is a polypeptide (e.g., an antibody or antigen-binding fragment thereof) that competes with any of these antibodies for binding to one or more Fzd receptors. [Table 1A-1] [Table 1A-2] [Table 1A-3] [Table 1A-4] [Table 1A-5] [Table 1A-6] [Table 1A-7] [Table 1A-8] [Table 1A-9] [Table 1A-10] [Table 1A-11] [Table 1A-12]

Table 1A-13

Table 1A-14

Table 1A-15

Table 1A-16

Table 1A-17

Table 1A-18

Table 1A-19

Table 1A-20

Table 1A-21

Table 1A-22

Table 1A-23

Table 1A-24

Table 1A-25

Table 1A-26

Table 1A-27

Table 1A-28

Table 1A-29

Table 1A-30

Table 1A-31

Table 1A-32

Table 1A-33

Table 1A-34

Table 1A-35

Table 1A-36

Table 1A-37

Table 1A-38

Table 1A-39

Table 1A-40

Table 1A-41

Table 1A-42

Table 1A-43

Table 1A-44

Table 1A-45

[0074] In certain embodiments, the Fzd binding domain is, for example, at least about 1×10 -4 M, at least about 1 × 10 -5 M, at least about 1 × 10 -6 M, at least about 1 × 10 -7 M, at least about 1 × 10 -8 M, at least about 1 × 10 -9 M, or at least about 1 × 10 -10 K of M DThe binding domain can be selected from any binding domain that binds to Fzd with an affinity of at least about 1×10. In certain embodiments, the Fzd binding domain binds to Fzd with high affinity, e.g., at least about 1×10. -7 Less than M, approx. 1×10 -8 Less than M, approx. 1×10 -9 Less than M or about 1×10 -10 K less than M D The binding domain may be selected from any binding domain that binds to one or more Fzd receptors with high affinity, e.g., about 1×10 in the context of a Wnt surrogate molecule. In certain embodiments, the Fzd binding domain binds to one or more Fzd receptors with high affinity, e.g., about 1×10 -4 M or less, approximately 1×10 -5 M or less, approximately 1×10 -6 M or less, approximately 1×10 -7 M or less, approximately 1×10 -8 M or less, approximately 1×10 -9 M or less, or at least about 1 × 10 -10 K of M D The binding domain may be selected from any binding domain that binds to Fzd at

[0075] Suitable Fzd binding domains include, but are not limited to, de novo designed Fzd binding proteins, antibody derived binding proteins (e.g., scFv, Fzb, etc.) and other portions of antibodies that specifically bind to one or more Fzd proteins; binding domains derived from VHH or single domain antibodies; knottin-based engineered scaffolds; Norrin and Norrin-derived engineered binding fragments, naturally occurring Fzd binding domains, etc. Fzd binding domains can be affinity selective to enhance binding to the desired Fzd protein or proteins, for example, to provide tissue selectivity.

[0076] In some embodiments, the Fzd binding domain binds one, two, three, four, five or more different frizzled proteins, e.g., one or more of the human frizzled proteins Fzd1, Fzd2, Fzd3, Fzd4, Fzd5, Fzd6, Fzd7, Fzd8, Fzd9, Fzd10. In some embodiments, the Fzd binding domain binds Fzd1, Fzd2, and Fzd7. In some embodiments, the Fzd binding domain binds Fzd1, Fzd2, Fzd5, Fzd7, and Fzd8. In other embodiments, the Fzd binding domain is selective for one or more desired frizzled proteins, e.g., has at least 10-fold, 25-fold, 50-fold, 100-fold, 200-fold, or more specificity for one or more desired frizzled proteins over other frizzled proteins.

[0077] In certain embodiments, the Fzd binding domain comprises the six CDR regions of the pan-specific frizzled antibody OMP-18R5 (vantictumab). In certain embodiments, the Fzd binding domain is an scFv comprising the six CDR regions of the pan-specific frizzled antibody OMP-18R5 (vantictumab). See, e.g., U.S. Patent No. 8,507,442 (specifically incorporated herein by reference). For example, the CDR sequences of OMP-18R5 comprise a heavy chain CDR1 comprising GFTFSHYTLS (SEQ ID NO:270), a heavy chain CDR2 comprising VISGDGSYTYYADSVKG (SEQ ID NO:677), and a heavy chain CDR3 comprising NFIKYVFAN (SEQ ID NO:1033); and (ii) a light chain CDR1 comprising SGDKLGKKYAS (SEQ ID NO:1152) or SGDNIGSFYVH (SEQ ID NO:1153), a light chain CDR2 comprising EKDNRPSG (SEQ ID NO:1200) or DKSNRPSG (SEQ ID NO:1201), and a light chain CDR3 comprising SSFAGNSLE (SEQ ID NO:1435) or QSYANTLSL (SEQ ID NO:1436). In certain embodiments, the Fzd binding domain is an antibody or derivative thereof, including, but not limited to, a scFv, a minibody, a VHH, or a single domain antibody (sdAb), and various antibody mimetics comprising any of these CDR sequences. In certain embodiments, the CDR sequences contain one or more amino acid modifications.

[0078] In other embodiments, the Fzd binding domain comprises variable region sequences or CDRs thereof from any of a number of frizzled specific antibodies, such antibodies being known in the art, commercially available, or can be generated de novo. Any frizzled polypeptide can be used as an immunogen or in screening assays to develop antibodies. Non-limiting examples of frizzled binding domains include antibodies available from Biolegend, such as clone CH3A4A7 specific for human frizzled 4 (CD344); clone W3C4E11 specific for human Fzd9 (CD349); antibodies available from Abcam, such as ab64636 specific for Fzd7; ab83042 specific for human Fzd4; ab77379 specific for human Fzd7; ab75235 specific for human Fzd8; ab102956 specific for human Fzd9; and the like. Other examples of suitable antibodies are described in, among others, U.S. Patent Application No. 20140105917, U.S. Patent Application No. 20130230521, U.S. Patent Application No. 20080267955, U.S. Patent Application No. 20080038272, U.S. Patent Application No. 20030044409, each of which is specifically incorporated herein by reference.

[0079] The Fzd-binding region of the Wnt surrogate molecule can be an engineered protein selected by structural homology to the frizzled-binding region of a Wnt protein. Such proteins can be identified by screening structural databases for homology. In this way, a first protein (e.g., a microbial Bh1478 protein) is identified. The native protein can then be engineered to provide amino acid substitutions that increase affinity, and further selected by affinity maturation to increase affinity and selectivity in binding to the desired frizzled protein. Non-limiting examples of frizzled-binding moieties include Fz27 and Fz27-B12 proteins.

[0080] In certain embodiments, the Wnt surrogate molecule comprises an LRP5 / 6 binding domain (e.g., an anti-LRP5 / 6 antibody) or an antigen-binding fragment thereof fused to a polypeptide that specifically binds to one or more Fzd receptors. In certain embodiments, the polypeptide that specifically binds to LRP5 / 6 is an antibody or an antigen-binding fragment thereof. In certain embodiments, it is an antibody or an antigen-binding fragment thereof disclosed in U.S. Provisional Patent Application No. 62 / 607,879, entitled "Anti-LR5 / 6 Antibodies and Methods of Use", filed December 19, 2017, Attorney Docket No. SRZN-005 / 00US, which is incorporated herein by reference in its entirety. In certain embodiments, the LRP5 / 6 binding domain comprises the three heavy chain CDRs and / or the three light chain CDRs disclosed for any of the exemplary antibodies or fragments thereof that bind to LRP5 and / or LRP6 shown in Table 2A. In certain embodiments, the LRP5 / 6 binding domain comprises the three heavy chain CDRs and / or the three light chain CDRs disclosed for any of the exemplary antibodies or fragments thereof that bind to one or more Fzd receptors shown in Table 2A, which CDRs collectively comprise one, two, three, four, five, six, seven, or eight amino acid modifications (e.g., substitutions, deletions, or additions). In certain embodiments, the LRP5 / 6 binding domain is a VHH or sdAb or is derived from a VHH or sdAb, such that Table 2A comprises only the three heavy chain CDRs. In certain embodiments, the LRP5 / 6 binding domain comprises the three heavy chain CDRs or variants shown in Table 2A, which CDRs collectively comprise one, two, three, four, five, six, seven, or eight amino acid modifications. In certain embodiments, the LRP5 / 6 binding domain comprises a heavy chain fragment and / or a light chain fragment of any exemplary antibody or fragment thereof (or any antigen-binding fragment or variant) that binds to LRP5 and / or LRP6 set forth in Table 2B or SEQ ID NOs: 66-88 or 133.In certain embodiments, the LRP5 / 6 binding domain is a Fab or is derived from a Fab such that Table 2B includes a VH and CH1 sequence but not a CH2 or CH3 sequence. In certain embodiments, the LRP5 / 6 binding domain is a VHH or sdAb or is derived from a VHH or sdAb such that Table 2B includes a VHH domain. In certain embodiments, the LRP5 / 6 binding region is a polypeptide (e.g., an antibody or antigen-binding fragment thereof) that competes with one of these antibodies for binding to LRP5 and / or LRP6. [Table 2A-1] [Table 2A-2] [Table 2A-3] [Table 2A-4] [Table 2A-5] [Table 2A-6] [Table 2A-7] [Table 2A-8] [Table 2A-9] [Table 2A-10] [Table 2A-11] [Table 2A-12] [Table 2A-13] [Table 2A-14] [Table 2A-15] [Table 2A-16] [Table 2A-17] [Table 2A-18] [Table 2A-19] [Table 2A-20] [Table 2B]

[0081] In certain embodiments, the LRP5 / 6 binding domain, in the context of a Wnt surrogate molecule, is about 1×10 -4 M or less, approximately 1×10 -5 M or less, approximately 1×10 -6 M or less, approximately 1×10 -7 M or less, approximately 1×10 -8 M or less, approximately 1×10 -9 M or less, or about 1 x 10 -10 K below M D The binding domain can be selected from any binding domain that binds to LRP5 or LRP6 at about 1×10 -4 M or more, approximately 1 x 10 -5 M or more, approximately 1 x 10 -6 M or more, approximately 1 x 10 -7 M or more, approximately 1 x 10 -8M or more, approximately 1 x 10 -9 M or more, or about 1×10 -10 K over M D The binding domain can be selected from any binding domain that binds to LRP5 or LRP6 with high affinity, e.g., about 1×10 -7 Less than M, approx. 1×10 -8 Less than M, approx. 1×10 -9 Less than M or about 1×10 -10 K less than M D The binding domain can be selected from any binding domain that binds to LRP5 or LRP6 at the

[0082] Other suitable LRP5 / 6 binding domains include, but are not limited to, de novo designed LRP5 / 6 binding proteins, antibody derived binding proteins (e.g., scFv, Fab, etc.), and other portions of antibodies that specifically bind one or more Fzd proteins; VHH or sdAb derived binding domains; knottin-based engineered scaffolds; native LRP5 / 6 (including, but not limited to, DKK1, DKK2, DKK3, DKK4, sclerostin); Wise; fusion proteins comprising any of the above; derivatives of any of the above; variants of any of the above; and biologically active fragments of any of the above. The LRP5 / 6 binding domain may be affinity selective to enhance binding.

[0083] Members of the Dickkopf (DKK) gene family (see Krupnik et al. (1999) Gene 238(2):301-13) include DKK-1, DKK-2, DKK-3, and DKK-4, as well as the DKK-3-related protein Soggy (Sgy). hDKK1-4 contain two distinct cysteine-rich domains in which the positions of the 10 cysteine ​​residues are highly conserved among family members. Exemplary sequences of human Dkk genes and proteins are publicly available, e.g., Genbank accession numbers NM_014419 (soggy-1); NM_014420 (DKK4); AF177394 (DKK-1); AF177395 (DKK-2); NM_015881 (DKK3); and NM_014421 (DKK2). In some embodiments of the invention, the Lrp6 binding moiety is a DKK1 peptide, including but not limited to the C-terminal domain of human DKK1. The C-terminal domain can comprise the sequence: KMYHTKGQEGSVCLRSSDCASGLCCARHFWSKICKPVLKEGQVCTKHRRKGSHGLEIFQRCYCGEGLSCRIQKDHHQASNSSRLHTCQRH (SEQ ID NO: 2190) (see Genbank Accession No. NP_036374), or a biologically active fragment thereof.

[0084] Binding of DKK proteins to LRP5 / 6 is discussed, for example, in Brott and Sokol Mol. Cell. Biol. 22(17), 6100-6110 (2002); and Li et al. J. Biol. Chem. 277(8), 5977-5981 (2002), each of which is expressly incorporated herein by reference. The corresponding region of human DKK2 (Genbank reference NP_055236) can comprise the sequence: KMSHIKGHEGDPCLRSSDCIEGFCCARHFWTKICKPVLHQGEVCTKQRKKGSHGLEIFQRCDCAKGLSCKVWKDATYSSKARLHVCQK (SEQ ID NO: 2191), or a biologically active fragment thereof.

[0085] Antibodies that specifically bind to LRP5 or LRP6 are known in the art, are commercially available, or can be newly generated. LRP5, LRP6, or fragments thereof can be used as immunogens or in screening assays to develop antibodies. Examples of known antibodies include, but are not limited to, those described in Gong et al. (2010) PLoS One. 5(9): e12682; Ettenberg et al. (2010) Proc Natl Acad Sci US Pat. No. 107(35):15473-8; and commercially available antibodies from, for example, Santa Cruz biotechnology antibody clone 1A12 (raised against synthetic LRP5 / 6 of human origin and binds to both full-length and proteolytic fragments of LRP6 and LRP5 of mouse and human origin); monoclonal antibody 2B11; Cell Signaling Technology antibody specific for LRP5 (D80F2), catalog number 5731;

[0086] In certain embodiments, the Wnt surrogate molecules disclosed herein comprise one or more polypeptides comprising two or more binding regions. For example, the two or more binding regions may be two or more Fzd binding regions or two or more LRP5 / 6 binding regions, or may comprise one or more Fzd binding regions and one or more LRP5 / 6 binding regions. The binding regions may be directly linked or adjacent, or may be separated by a linker (e.g., a polypeptide linker or a non-peptide linker, etc.). The length of the linker, i.e., the spacing between the binding domains, may be used to adjust the signal strength and may be selected depending on the desired use of the Wnt surrogate molecule. The required distance between the binding domains may vary, but in certain embodiments may be less than about 100 angstroms, less than about 90 angstroms, less than about 80 angstroms, less than about 70 angstroms, less than about 60 angstroms, or less than about 50 angstroms. In some embodiments, the linker is a rigid linker, and in other embodiments, the linker is a flexible linker. In certain embodiments, when the linker is a peptide linker, the linker can be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or more amino acids in length and of sufficient length and amino acid composition to enhance the distance between the binding domains. In some embodiments, the linker comprises or consists of one or more glycine and / or serine residues.

[0087] In certain embodiments, a Wnt surrogate molecule comprises a polypeptide sequence having at least 90%, at least 95%, at least 98%, or at least 99% identity to a polypeptide sequence disclosed in any of SEQ ID NOs: 89-128 or 134-157, or having at least 90%, at least 95%, at least 98%, or at least 99% identity to an antigen-binding fragment of a polypeptide sequence disclosed in any of SEQ ID NOs: 89-128 or 134-157. In certain embodiments, a Wnt surrogate molecule comprises or consists of a polypeptide sequence set forth in any of SEQ ID NOs: 89-128 or 134-157, or an antigen-binding fragment thereof. In certain embodiments, the antigen-binding fragment binds to one or more Fzd receptors and further binds to LRP5 and / or LRP6.

[0088] Wnt surrogate molecules can be multimerized, for example, via the Fc domain, by linkage, coiled coil, polypeptide zipper, biotin / avidin or streptavidin multimerization, etc. Wnt surrogate molecules can also be linked to moieties such as PEG, Fc, etc., as known in the art, to enhance stability in vivo.

[0089] In certain embodiments, Wnt surrogate molecules directly activate canonical Wnt signaling by binding to one or more Fzd proteins and LRP5 / 6, particularly by binding to these proteins on the cell surface, e.g., on the surface of human cells. Direct activation of Wnt signaling by Wnt surrogate molecules is in contrast to enhanced Wnt signaling, which enhances activity only in the presence of native Wnt protein.

[0090] Wnt surrogate molecules can activate Wnt signaling, for example, by mimicking the effect or activity of Wnt protein that binds to frizzled protein. The ability of the Wnt surrogate molecules of the present invention to mimic the activity of Wnt can be confirmed by multiple assays. Wnt surrogate molecules typically initiate similar or identical reactions or activities to those initiated by the natural ligand of receptor. In particular, the Wnt surrogate molecules of the present invention enhance the canonical Wnt / β-catenin signaling pathway. As used herein, the term "enhance" refers to a measurable increase in the level of Wnt / β-catenin signaling compared to the level in the absence of the Wnt surrogate molecules of the present invention.

[0091] Various methods for measuring the level of Wnt / β-catenin signaling are known in the art. Such methods include, but are not limited to, assays that measure Wnt / β-catenin target gene expression, TCF reporter gene expression, β-catenin stabilization, LRP phosphorylation, translocation of axin from the cytoplasm to the cell membrane and binding to LRP. The canonical Wnt / β-catenin signaling pathway ultimately leads to changes in gene expression via transcription factors TCF7, TCF7L1, TCF7L2 (also known as TCF4), and LEF. The transcriptional response to Wnt activation has been characterized in multiple cells and tissues. Thus, global transcriptional profiling by methods known in the art can be used to assess activation or inhibition of Wnt / β-catenin signaling.

[0092] Changes in Wnt-responsive gene expression are generally mediated by TCF and LEF transcription factors. The TCF reporter assay assesses changes in transcription of TCF / LEF-regulated genes to determine the level of Wnt / β-catenin signaling. The TCF reporter assay was first described by Korinek, V. et al., 1997. Also known as TOP / FOP, this method involves determining the transactivation activity of endogenous p-catenin / TCF4 using three copies of the optimal TCF motif CCTTTGATC or three copies of the mutant motif CCTTTGGCC upstream of a minimal c-Fos promoter driving luciferase expression (pTOPFl_ASH and pFOPFl_ASH, respectively). A higher ratio of the two reporter activities (TOP / FOP) indicates higher β-catenin / TCF4 activity, and a lower ratio of the two reporter activities indicates lower β-catenin / TCF4 activity.

[0093] A variety of other reporter transgenes that respond to Wnt signals are present in animals in an intact state, and therefore effectively reflect endogenous Wnt signaling. Such reporters are based on the multimerized TCF binding sites that drive the expression of LacZ or GFP, and can be easily detected by methods known in the art. Such reporter genes include TOP-GAL, BAT-GAL, ins-TOPEGFP, ins-TOPGAL, LEF-EGFP, Axin2-LacZ, Axin2-d2EGFP, Lgr5tm1(cre / ERT2), and TOPdGFP.

[0094] The recruitment of dephosphorylated β-catenin to the membrane, the stabilization and phosphorylation state of β-catenin, and the translocation of β-catenin to the nucleus (Klapholz-Brown Z et al., PLoS One.2(9)e945,2007), in some cases mediated by complex formation with TCF transcription factors and TNIK, are key steps in the Wnt signaling pathway. Stabilization is mediated by the Dishevelled family proteins that inhibit the "destruction" complex, resulting in reduced degradation of intracellular β-catenin and subsequent translocation of β-catenin to the nucleus. Therefore, measuring the level and location of β-catenin in cells is a good reflection of the level of Wnt / β-catenin signaling. One non-limiting example of such an assay is the "BioImage β-Catenin Redistribution Assay" (Thermo Scientific), which provides recombinant U20S cells stably expressing human β-catenin fused to the C-terminus of enhanced green fluorescent protein (EGFP). Imaging and analysis are performed using a fluorescent microscope or HCS platform that allows visualization of the levels and distribution of EGFP-β-catenin.

[0095] Another way to inhibit the destruction complex is by axin removal by recruiting axin to the cytoplasmic tail of the Wnt co-receptor LRP. Axin has been shown to preferentially bind to the phosphorylated form of the LRP tail. Therefore, visualization of axin translocation (e.g., with a GFP-axin fusion protein) is another way to assess the levels of Wnt / β-catenin signaling.

[0096] In certain embodiments, the Wnt surrogate molecule enhances or increases canonical Wnt signaling (e.g., β-catenin signaling) by at least 30%, 35%, 40%, 45%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 110%, 150%, 200%, 250%, 300%, 400%, or 500% compared to β-catenin signaling induced by a neutral agent or negative control, as measured in the above assays, e.g., TOPFlash assay. Such assays may include a negative control. In certain embodiments, the Wnt surrogate molecule can enhance β-catenin signaling by 2-fold, 5-fold, 10-fold, 100-fold, 1000-fold, 10,000-fold, or more compared to activity in the absence of the Wnt surrogate molecule, as measured in any of the assays described above, e.g., the TOPFlash assay, or other assays referred to herein.

[0097] "Wnt gene product" or "Wnt polypeptide" as used herein encompasses native sequence Wnt polypeptides, Wnt polypeptide variants, Wnt polypeptide fragments, and chimeric Wnt polypeptides. In certain embodiments, the Wnt polypeptide is a native human full-length mature Wnt protein.

[0098] For example, human native sequence Wnt proteins of interest in the present application include the following: Wnt-1 (GenBank Accession No. NM_005430); Wnt-2 (GenBank Accession No. NM_003391); Wnt-2B (Wnt-13) (GenBank Accession Nos. NM_004185 (isoform 1), NM_024494.2 (isoform 2)), Wnt-3 (RefSeq.: NM_030753), Wnt3a (GenBank Accession No. NM_033131), Wnt-4 (GenBank Accession No. NM_030761), Wnt-5A (GenBank Accession No. NM_003392), Wnt-5B (GenBank Accession No. NM_032642), Wnt-6 (GenBank Accession No. NM_032642), Wnt-7 (GenBank Accession No. NM_032642), Wnt-8 (GenBank Accession No. NM_032642), Wnt-9 (GenBank Accession No. NM_032642), Wnt-10 (GenBank Accession No. NM_032642), Wnt-11 (GenBank Accession No. NM_032642), Wnt-12 (GenBank Accession No. NM_032642), Wnt-13 (GenBank Accession No. NM_032642), Wnt-14 (GenBank Accession No. NM_032642), Wnt-15 (GenBank Accession No. NM_032642), Wnt-16 (GenBank Accession No. NM_032642), Wnt-17 (GenBank Accession No. NM_032642), Wnt-18 (GenBank Accession No. NM_032642), Wnt-19 (GenBank Access _006522), Wnt-7A (GenBank Accession No. NM_004625), Wnt-7B (GenBank Accession No. NM_058238), Wnt-8A (GenBank Accession No. NM_058244), Wnt-8B (GenBank Accession No. NM_003393), Wnt-9A (Wnt-14) (GenBank Accession No. NM_00339 5), Wnt-9B (Wnt-15) (GenBank Accession No. NM_003396), Wnt-10A (GenBank Accession No. NM_025216), Wnt-10B (GenBank Accession No. NM_003394), Wnt-11 (GenBank Accession No. NM_004626), and Wnt-16 (GenBank Accession No. NM_016087)). Although individual members have varying degrees of sequence identity to the family, all encode small (i.e., 39-46 kD), secreted glycoproteins that are acylated, palmitoylated, and contain 23-24 conserved cysteine ​​residues with highly conserved spacing (McMahon, AP et al., Trends Genet. 1992;8:236-242; Miller, JR. Genome Biol. 2002;3(1):3001.1-3001.15).Other native sequences of the Wnt polypeptide of interest include orthologs of the above from any mammal, including domestic and farm animals, as well as zoo, laboratory, or pet animals, such as dogs, cats, cows, horses, sheep, pigs, goats, rabbits, rats, mice, frogs, zebrafish, fruit flies, worms, etc.

[0099] "Wnt pathway signaling" or "Wnt signaling" is used herein to refer to the mechanism by which biologically active Wnt exerts its effect on a cell to regulate the activity of the cell. Wnt proteins regulate cellular activity by binding to Wnt receptors, including proteins from the Frizzled (Fzd) family of proteins, proteins from the ROR family of proteins, proteins LRP5, LRP6, proteins FRL1 / crypto, and proteins Derailed / Ryk from the LRP family of proteins. Once activated by Wnt binding, the Wnt receptor(s) activate one or more intracellular signaling cascades. Such signaling cascades include the canonical Wnt signaling pathway; the Wnt / planar cell polarity (Wnt / PCP) pathway; the Wnt-calcium (Wnt / Ca 2+ ) pathway (Giles,RH et al.(2003) Biochim Biophys Acta 1653,1-24;Peifer,M.et al.(1994) Development 120:369-380;Papkoff,J.et al(1996) Mol.Cell Biol. 16:2128-2134; Veeman, MT et al. (2003) Dev. Cell 5:367-377); and other Wnt signaling pathways as known in the art.

[0100] For example, activation of the canonical Wnt signaling pathway results in the inhibition of phosphorylation of the intracellular protein β-catenin, leading to its accumulation in the cytosol and subsequent translocation to the nucleus, where it interacts with transcription factors (e.g., TCF / LEF) to activate target genes. Activation of the Wnt / PCP pathway activates RhoA, c-Jun N-terminal kinase (JNK), and nemo-like kinase (NLK) signaling cascades to control biological processes such as tissue polarity and cell motility. For example, Wnt / Ca2+ signaling by binding Wnt-4, Wnt-5A, or Wnt-11 is involved in the activation of the cascades. 2+ Activation of induces intracellular release of calcium ions, which activates calcium-sensitive enzymes such as protein kinase C (PKC), calcium-calmodulin-dependent kinase II (CamKII), or calcineurin (CaCN). By assaying the activity of the above signaling pathways, the biological activity of an antibody or antigen-binding fragment thereof (e.g., a Wnt surrogate molecule) can be readily determined.

[0101] In certain embodiments, the functional properties of Wnt surrogate molecules can be assessed using a variety of methods known to those of skill in the art, including, for example, affinity / binding assays (e.g., surface plasmon resonance, competitive inhibition assays), cytotoxicity assays, cell viability assays, cell proliferation or differentiation assays in response to Wnt, cancer cells, and / or tumor growth inhibition using in vitro or in vivo models (including, but not limited to, any of those described herein). The Wnt surrogate molecules described herein can also be tested for their effect on Fzd receptor internalization, in vitro and in vivo efficacy, and the like. Such assays can be performed using well-established protocols known to those skilled in the art (see, e.g., Current Protocols in Molecular Biology (Greene Publ. Assoc. Inc. & John Wiley & Sons, Inc., NY, NY); Current Protocols in Immunology (eds. John E. Coligan, Ada M. Kruisbeek, David H. Margulies, Ethan M. Shevach, Warren Strober 2001 John Wiley & Sons, NY, NY) or commercially available kits.

[0102] In certain embodiments, the Fzd-binding region of the Wnt surrogate molecule (e.g., an antigen-binding fragment of an anti-Fzd antibody) comprises one or more of the CDRs of the anti-Fzd antibody described herein. In certain embodiments, the LRP5 / 6-binding region of the Wnt surrogate molecule (e.g., an antigen-binding fragment of an anti-LRP5 / 6 antibody) comprises one or more of the CDRs of the anti-LRP5 / 6 antibody described herein. In this regard, it has been shown that in some cases, transfer of only the VHCDR3 of an antibody can be performed while retaining the desired specific binding (Barbas et al., PNAS (1995) 92: 2529-2533). See also McLane et al., PNAS (1995) 92: 5214-5218, Barbas et al., J. Am. Chem. Soc. (1994) 116: 2161-2162.

[0103] Also disclosed herein is a method for obtaining an antibody or antigen-binding domain specific for a Fzd receptor, comprising providing a VH domain as set forth herein or an amino acid sequence variant of said VH domain by addition, deletion, substitution or insertion of one or more amino acids in said VH domain's amino acid sequence, optionally combining the VH domain thus provided with one or more VL domains, and testing the VH domain or VH / VL combination(s) to identify specific binding members of the antibody antigen-binding domain specific for one or more Fzd receptors and optionally having one or more desired properties. The VL domain may have an amino acid sequence substantially as set forth herein. Similar methods may be used in which one or more sequence variants of the VL domain disclosed herein are combined with one or more VH domains.

[0104] In certain embodiments, the Wnt surrogate molecule is water-soluble. By "water-soluble" is meant a composition that is soluble in an aqueous buffer in the absence of detergent and is usually soluble at a concentration that provides a biologically effective dose of the polypeptide. A composition that is water-soluble forms a substantially homogeneous composition, and the specific activity of the composition is at least about 5% of the starting material from which it is purified, usually at least about 10%, 20%, or 30%, more usually about 40%, 50%, or 60%, and sometimes about 50%, about 90%, or more. The Wnt surrogate molecules disclosed herein typically form a substantially homogeneous aqueous solution at a concentration of at least 25 μM or more, for example, at least 25 μM, 40 μM, or 50 μM, usually at least 60 μM, 70 μM, 80 μM, or 90 μM, and sometimes as high as 100 μM, 120 μM, or 150 μM. In other words, the Wnt surrogate molecules disclosed herein typically form a substantially homogenous aqueous solution at a concentration of about 0.1 mg / ml, about 0.5 mg / ml, about 1 mg / ml or more.

[0105] An antigen or epitope that "specifically binds" or "preferentially binds" (used interchangeably herein) to an antibody or antigen-binding fragment thereof is a term well understood in the art, and methods for determining such specific or preferential binding are also well known in the art. A molecule (e.g., a Wnt surrogate molecule) is said to exhibit "specific binding" or "preferential binding" if it reacts or associates with a particular cell or substance more frequently, rapidly, with longer duration, and / or with higher affinity than alternative cells or substances. A molecule or binding region thereof (e.g., a Wnt surrogate molecule or binding region thereof) "specifically binds" or "preferentially binds" to a target antigen (e.g., a Fzd receptor) if the antibody binds with greater affinity, avidity, more readily, and / or with longer duration than to other substances. For example, a Wnt surrogate molecule or binding region thereof that specifically or preferentially binds to the Fzd1 receptor is an antibody that binds to the Fzd1 receptor with greater affinity, avidity, more readily, and / or with longer duration than to other Fzd receptors or non-Fzd proteins. It is also understood by reading this definition that, for example, a Wnt surrogate molecule or binding region thereof that specifically or preferentially binds to a first target may or may not specifically or preferentially bind to a second target. Thus, "specific binding" or "preferential binding" does not necessarily require (but can include) exclusive binding. Generally, but not necessarily, reference to binding refers to preferential binding.

[0106] In some embodiments, any of the one or more Fzd binding regions of the Wnt surrogate molecule binds to one, two, three, four, five or more different frizzled proteins, such as one or more of the human frizzled proteins Fzd1, Fzd2, Fzd3, Fzd4, Fzd5, Fzd6, Fzd7, Fzd8, Fzd9, Fzd10. In some embodiments, any Fzd binding region binds to Fzd1, Fzd2, Fzd5, Fzd7, and Fzd8. In various embodiments, any Fzd binding region binds to: (i) Fzd1, Fzd2, Fzd7, and Fzd9; (ii) Fzd1, Fzd2, and Fzd7; (iii) Fzd5 and Fzd8; (iv) Fzd5, Fzd7, and Fzd8; (v) Fzd1, Fzd4, Fzd5, and Fzd8; (vi) Fzd1, Fzd2, Fzd5, Fzd7, and Fzd8; (vii) Fzd4 and Fzd9; (viii) Fzd9 and Fzd10; (ix) Fzd5, Fzd8, and Fzd10; (x) Fzd4, Fzd5, and Fzd8; Fzd1, Fzd5, Fzd7, and Fzd8. In some embodiments, the Fzd binding region is selective for one or more Fzd proteins of interest, e.g., has at least 10-fold, 25-fold, 50-fold, 100-fold, 200-fold or more specificity for one or more desired Fzd proteins versus other Fzd proteins. In some embodiments, any of the one or more Fzd binding regions of the Wnt surrogate molecule is monospecific, specifically binding to only one of Fzd1, Fzd2, Fzd3, Fzd4, Fzd5, Fzd6, Fzd7, Fzd8, Fzd9, or Fzd10.

[0107] In some embodiments, any of the one or more LRP5 / 6 binding regions of a Wnt surrogate molecule binds to one or both of LRP5 / 6. For convenience, the term "LRP5 / 6" is used to refer collectively to either or both of LRP5 and / or LRP6.

[0108] Immunological binding generally refers to the types of non-covalent interactions that occur between immunoglobulin molecules and the antigens for which the immunoglobulin molecules are specific, including, by way of example and not limitation, electrostatic, ionic, hydrophilic and / or hydrophobic attractions or repulsions, steric forces, hydrogen bonding, van der Waals forces, and other interactions. The strength or affinity of an immunological binding interaction is determined by the dissociation constant (K d ), and K d A smaller K represents a greater affinity. The immunological binding properties of a selected polypeptide can be quantified using methods well known in the art. One such method involves measuring the rates of formation and dissociation of the antigen-binding site / antigen complex, which depend on the concentrations of the complex partners, the affinity of the interaction, and geometric parameters that affect the rates in both directions equally. Thus, the "on-rate constant" (K on ) and "off rate constant" (K off ) can be determined by calculation of the concentrations and the actual rates of association and dissociation. off / K on The ratio of d See generally, Davies et al. (1990) Annual Rev Biochem. 59:439-473.

[0109] In certain embodiments, the Wnt surrogate molecules or binding regions thereof described herein have an affinity for one or more Fzd receptors or LRP5 or LRP6 receptors of less than about 10,000, less than about 1000, less than about 100, less than about 10, less than about 1, or less than about 0.1 nM, and in some embodiments the antibodies may have even higher affinities.

[0110] The constant regions of immunoglobulins exhibit less sequence diversity than the variable regions and are responsible for binding to multiple natural proteins to trigger important biochemical events. In humans, there are five different antibody classes, including IgA (including subclasses IgA1 and IgA2), IgD, IgE, IgG (including subclasses IgG1, IgG2, IgG3, and IgG4), and IgM. The distinguishing feature of these antibody classes is the constant region, although subtler differences may exist within the V region.

[0111] The Fc region of an antibody interacts with multiple Fc receptors and ligands, conferring a number of important functional capabilities, called effector functions. In the case of IgG, the Fc region contains the Ig domains CH2 and CH3, with an N-terminal hinge connecting to CH2. An important family of Fc receptors in the IgG class are the Fc gamma receptors (FcγR). These receptors mediate communication between the antibody and the cellular arms of the immune system (Raghavan et al., 1996, Annu Rev Cell Dev Biol 12:181-220; Ravetch et al., 2001, Annu Rev Immunol 19:275-290). In humans, this protein family includes FcγRI (CD64) (which includes isoforms FcγRIa, FcγRIb, and FcγRIc); FcγRII (CD32) (which includes isoforms FcγRIIa (including allotypes H131 and R131), FcγRIIb (including FcγRIIb-1 and FcγRIIb-2), and FcγRIIc); and FcγRIII (CD16) (which includes isoforms FcγRIIIa (including allotypes V158 and F158) and FcγRIIIb (including allotypes FcγRIIIb-NA1 and FcγRIIIb-NA2) (Jefferis et al., 2002, Immunol Lett. 82:57-65). These receptors typically have an extracellular domain that mediates binding to Fc, a transmembrane region, and an intracellular domain that may mediate some intracellular signaling events. These receptors are expressed in a variety of immune cells, including monocytes, macrophages, neutrophils, dendritic cells, eosinophils, mast cells, platelets, B cells, large granular lymphocytes, Langerhans cells, natural killer (NK) cells, and T cells. Formation of the Fc / FcγR complex recruits these effector cells to the site of binding antigen, typically resulting in intracellular signaling events and subsequent important immune responses, such as release of inflammatory mediators, B cell activation, endocytosis, phagocytosis, and cytotoxic attack.

[0112] The ability to mediate cytotoxic and phagocytic effector functions is a potent mechanism by which antibodies destroy target cells. The cell-mediated reaction in which non-specific cytotoxic cells expressing FcγR recognize bound antibodies on target cells and subsequently cause lysis of the target cells is called antibody-dependent cell-mediated cytotoxicity (ADCC) (Raghavan et al., 1996, Annu Rev Cell Dev Biol 12:181-220; Ghetie et al., 2000, Annu Rev Immunol 18:739-766; Ravetch et al., 2001, Annu Rev Immunol 19:275-290). The cell-mediated reaction in which non-specific cytotoxic cells expressing FcγR recognize bound antibodies on target cells and subsequently cause phagocytosis of the target cells is called antibody-dependent cell-mediated phagocytosis (ADCP). All FcγRs bind to the same region on Fc, at the N-terminus of the Cg2 (CH2) domain and immediately preceding the hinge. This interaction has been well characterized structurally (Sondermann et al., 2001, J Mol Biol 309:737-749), and several structures of human Fc bound to the extracellular domain of human FcγRIIIb have been solved (pdb accession code 1E4K) (Sondermann et al., 2000, Nature 406:267-273) (pdb accession codes 1IIS and 1IIX) (Radaev et al., 2001, J Biol Chem 276:16469-16477).

[0113] Different IgG subclasses have different affinities for FcγRs, and typically IgG1 and IgG3 bind substantially better to the receptor than IgG2 and IgG4 (Jefferis et al., 2002, Immunol Lett 82:57-65). All FcγRs bind to the same region on the IgG Fc, but with different affinities, with the high affinity binder FcγRI binding 10 -8 M -1 K D and the low affinity receptors FcγRII and FcγRIII are roughly 10 -6 and 10 -5FcγRIIIa and FcγRIIIb bind to the IgG1 receptor at the IL-1 domain. The extracellular domains of FcγRIIIa and FcγRIIIb are 96% identical, but FcγRIIIb does not have an intracellular signaling domain. Furthermore, FcγRI, FcγRIIa / c, and FcγRIIIa are positive regulators characterized by an intracellular domain with an immunoreceptor tyrosine-based activation motif (ITAM), whereas FcγRIIb has an immunoreceptor tyrosine-based inhibitory motif and is therefore inhibitory. Thus, the former are called activating receptors and FcγRIIb is called an inhibitory receptor. These receptors also differ in their patterns and levels of expression on different immune cells. Another level of complexity is the presence of multiple FcγR polymorphisms in the human proteome. A polymorphism of particular relevance to clinical importance is the V158 / F158 FcγRIIIa. Human IgG1 binds to the V158 allotype with higher affinity than to the F158 allotype. This difference in affinity, and its putative effect on ADCC and / or ADCP, has been shown to be an important determinant of efficacy for the anti-CD20 antibody rituximab (Rituxan®, a registered trademark of IDEC Pharmaceuticals Corporation). Subjects with the V158 allotype respond favorably to rituximab treatment, whereas subjects with the low affinity F158 allotype do not respond well (Cartron et al., 2002, Blood 99:754-758). Approximately 10-20% of humans are V158 / V158 homozygous, 45% are V158 / F158 heterozygous, and 35-45% of humans are F158 / F158 homozygous (Lehrnbecher et al., 1999, Blood 94:4220-4232; Cartron et al., 2002, Blood 99:754-758). Thus, 80-90% of humans are poor responders, i.e., they have at least one F158 FcγRIIIa allele.

[0114] The Fc region is also involved in the activation of the complement cascade. In the classical complement pathway, C1 binds by its C1q subunit to the Fc fragment of IgG or IgM complexed with antigen(s). In certain embodiments of the present invention, modifications to the Fc region alter (enhance or decrease) the ability of the Fzd-specific antibodies described herein to activate the complement system (see, e.g., U.S. Pat. No. 7,740,847). To assess complement activation, a complement-dependent cytotoxicity (CDC) assay can be performed (see, e.g., Gazzano-Santoro et al., J. Immunol. Methods, 202:163 (1996)).

[0115] Thus, in certain embodiments, the invention provides anti-Fzd antibodies having modified Fc regions with altered functional properties (e.g., reduced or enhanced CDC, ADCC, or ADCP activity, or enhanced binding affinity for a particular FcγR, or increased serum half-life). Other modified Fc regions contemplated herein are described, e.g., in issued U.S. Patent Nos. 7,317,091, 7,657,380, 7,662,925, 6,538,124, 6,528,624, 7,297,775, 7,364,731, published U.S. applications US2009092599, US20080131435, US20080138344, and published international applications WO2006 / 105338, WO2004 / 063351, WO2006 / 088494, WO2007 / 024249.

[0116] In certain embodiments, the Wnt surrogate molecule comprises an antibody variable domain with a desired binding specificity fused to an immunoglobulin constant domain sequence. H 2, and C H In a specific embodiment, the fusion is with an Ig heavy chain constant domain containing at least a portion of the C3 region. H1) is present in at least one of the fusions. DNA encoding the immunoglobulin heavy chain fusions and (if desired) the immunoglobulin light chain are inserted into separate expression vectors and co-transfected into a suitable host cell. This allows for more flexibility in adjusting the mutual ratios of the three polypeptide fragments in embodiments where unequal ratios of the three polypeptide chains are used in the construction to provide optimal yields of the desired bispecific antibody. However, it is possible to insert the coding sequences for two or all three polypeptide chains into a single expression vector in cases where expression of at least two polypeptide chains in equal ratios provides high yields or where the ratio does not significantly affect the yield of the desired chain combination.

[0117] The Wnt surrogate molecules disclosed herein can also be modified to include epitope tags or labels, for example, for use in purification or diagnostic applications. Numerous linking groups for making antibody conjugates are known in the art, including, for example, those disclosed in U.S. Pat. No. 5,208,020 or European Patent No. 0 425 235 B1, and Chari et al., Cancer Research 52:127-131 (1992). Linking groups include disulfide groups, thioether groups, acid labile groups, photolabile groups, peptidase labile groups, or esterase labile groups, as disclosed in the patents identified above, with disulfide groups and thioether groups being preferred.

[0118] In certain embodiments, the anti-LRP5 / 6 antibodies and / or anti-Fzd antibodies and / or anti-Fzd antibodies present in the Wnt surrogate molecule are monoclonal. In certain embodiments, they are humanized.

[0119] The present invention further provides, in certain embodiments, isolated nucleic acids that encode polypeptides present within the Wnt surrogate molecules disclosed herein. Nucleic acids include DNA and RNA. These and related embodiments can include polynucleotides that encode antibody fragments that bind to one or more Fzd receptors and / or LRP5 or LRP6 as described herein. As used herein, the term "isolated polynucleotide" shall mean a polynucleotide of genomic, cDNA, or synthetic origin, or any combination thereof, and based on its origin, an isolated polynucleotide (1) is not associated with all or a portion of a polynucleotide when the isolated polynucleotide is found in nature, (2) is associated with a polynucleotide with which it is not associated in nature, or (3) does not occur as part of a larger sequence in nature. An isolated polynucleotide can include natural and / or artificial sequences.

[0120] The term "operably linked" means that the components to which the term is applied are in a relationship allowing them to carry out their inherent functions under suitable conditions. For example, a transcription control sequence "operably linked" to a protein coding sequence is ligated with the protein coding sequence such that expression of the protein coding sequence is achieved under conditions compatible with the transcriptional activity of the control sequence.

[0121] As used herein, the term "control sequence" refers to a polynucleotide sequence capable of influencing the expression, processing, or subcellular localization of a coding sequence to which it is linked or operably linked. The nature of such control sequences may depend on the host organism. In certain embodiments, a prokaryotic transcription control sequence may include a promoter, a ribosomal binding site, and a transcription termination sequence. In other particular embodiments, a eukaryotic transcription control sequence may include a promoter including recognition sites for one or more transcription factors, a transcription enhancer sequence, a transcription termination sequence, and a polyadenylation sequence. In certain embodiments, a "control sequence" may include a leader sequence and / or a fusion partner sequence.

[0122] As referred to herein, the term "polynucleotide" refers to a single-stranded or double-stranded nucleic acid polymer. In certain embodiments, the nucleotides that comprise a polynucleotide can be ribonucleotides or deoxyribonucleotides, or modified forms of either type of nucleotide. Such modifications include base modifications (e.g., bromouridine), ribose modifications (e.g., arabinoside and 2',3'-dideoxyribose), and internucleotide bond modifications (e.g., phosphorothioate, phosphorodithioate, phosphoroselenoate, phosphorodiselenoate, phosphoroanilothioate, phosphoraniladate, and phosphoroamidate). The term "polynucleotide" specifically includes single-stranded and double-stranded forms of DNA.

[0123] The term "natural nucleotides" includes deoxyribonucleotides and ribonucleotides. The term "modified nucleotides" includes nucleotides having modified or substituted sugar groups, etc. The term "oligonucleotide linkages" includes oligonucleotide linkages such as phosphorothioate, phosphorodithioate, phosphoroselenoate, phosphorodiselenoate, phosphoroanilothioate, phosphoraniladate, phosphoroamidate, etc. See, e.g., LaPlanche et al., 1986, Nucl. Acids. Res.,14:9081;Stec et al.,1984,J.Am.Chem.Soc.,106:6077;Stein et al.,1988,Nucl.Acids Res.,16:3209;Zon et al.,1991,Anti-Cancer Drug Design,6:539;Zon et al.,1991,OLIGONUCLEOTIDES AND ANALOGUES:A PRACTICAL APPROACH,pp.87-108(F.Eckstein,Ed.),Oxford University Press,Oxford England;Stec See Uhlmann and Peyman, 1990, Chemical Reviews, 90:543, the disclosures of which are incorporated herein by reference for all purposes. The oligonucleotide can contain a detectable label to allow for detection of the oligonucleotide or its hybridization.

[0124] The term "vector" is used to refer to any molecule (e.g., nucleic acid, plasmid, or virus) used to transfer coding information to a host cell. The term "expression vector" refers to a vector that is suitable for transformation of a host cell and contains nucleic acid sequences that direct and / or control the expression of an inserted heterologous nucleic acid sequence. Expression includes processes such as, but are not limited to, transcription, translation, and, if introns are present, RNA splicing.

[0125] As will be understood by those skilled in the art, polynucleotides can include genomic sequences, extragenomic and plasmid coding sequences, and smaller engineered gene segments that express, or can be adapted to express, proteins, polypeptides, peptides, etc. Such segments may be naturally isolated or synthetically modified by one of skill in the art.

[0126] As will also be appreciated by those skilled in the art, polynucleotides may be single-stranded (coding or antisense) or double-stranded, and may be DNA molecules (genomic, cDNA, or synthetic) or RNA molecules. RNA molecules may include HnRNA molecules, which contain introns and correspond one-to-one to DNA molecules, and mRNA molecules, which do not contain introns. Additional coding or non-coding sequences may, but need not, be present within a polynucleotide in accordance with the present disclosure, and the polynucleotide may, but need not, be associated with other molecules and / or supporting materials. Polynucleotides may include native sequences or may include sequences that encode variants or derivatives of such sequences.

[0127] Those skilled in the art will understand that, as a result of the degeneracy of genetic code, there are many nucleotide sequences that code for the antibody described herein.Some of these polynucleotides have minimal sequence identity with the nucleotide sequence of the native or original polynucleotide sequence that codes for the polypeptide in the Wnt surrogate molecule.Nevertheless, the present disclosure expressly contemplates polynucleotides that differ due to differences in codon usage.In certain embodiments, sequences that are codon-optimized for mammalian expression are specifically contemplated.

[0128] Therefore, in another embodiment of the invention, a mutagenesis approach (e.g., site-directed mutagenesis) may be used for the preparation of variants and / or derivatives of the polypeptides described herein. By this approach, specific modifications in the polypeptide sequence may be made through mutagenesis of the underlying polynucleotides that encode them. These techniques introduce one or more nucleotide sequence changes into the polynucleotide, thereby providing a straightforward approach for preparing and testing sequence variants, for example incorporating one or more of the above considerations.

[0129] Site-directed mutagenesis allows for the production of mutants by providing primer sequences of sufficient size and sequence complexity to form stable duplexes on either side of the deletion junction being traversed, using specific oligonucleotide sequences that encode the DNA sequence of the desired mutation, and a sufficient number of flanking nucleotides. Mutations can be used in selected polynucleotide sequences to improve, alter, reduce, modify, or otherwise change the properties of the polynucleotide itself, and / or to alter the properties, activity, composition, stability, or primary sequence of the encoded polypeptide.

[0130] In certain embodiments, the inventors contemplate mutagenesis of a polynucleotide sequence encoding a polypeptide present in a Wnt surrogate molecule to modify one or more properties of the encoded polypeptide (e.g., binding affinity, or a specific Fc region function, or affinity of the Fc region for a specific FcγR). The technique of site-directed mutagenesis is well known in the art and is widely used to create variants of both polypeptides and polynucleotides. For example, site-directed mutagenesis is often used to modify specific portions of DNA molecules. In such embodiments, primers typically containing about 14 to about 25 nucleotides in length are used, and about 5 to about 10 residues on either side of the junction of the sequence are modified.

[0131] As those skilled in the art will understand, site-directed mutagenesis techniques often use phage vectors that exist in both single-stranded and double-stranded forms. Typical vectors useful for site-directed mutagenesis include vectors such as M13 phage. Such phages are readily commercially available, and their use is widely known to those skilled in the art. Double-stranded plasmids are also commonly used in site-directed mutagenesis, which eliminates the step of transferring the gene of interest from the plasmid to the phage.

[0132] The preparation of sequence variants of DNA segments encoding selected peptides using site-directed mutagenesis provides a means of producing potentially useful species and is not intended to be limiting, as there are other methods by which sequence variants of the peptides and DNA sequences encoding them can be obtained. For example, recombinant vectors encoding the desired peptide sequence can be treated with mutagenic agents such as hydroxylamine to obtain sequence variants. Specific details regarding such methods and protocols can be found in the teachings of Maloy et al., 1994; Segal, 1976; Prokop and Bajpai, 1991; Kuby, 1994; and Maniatis et al., 1982, each of which is incorporated herein by reference for this purpose.

[0133] In many embodiments, one or more nucleic acids encoding the polypeptides of the Wnt surrogate molecules are directly introduced into the host cells, and the cells are incubated under conditions sufficient to induce expression of the encoded polypeptides. The Wnt surrogate polypeptides of the present disclosure can be prepared using standard techniques well known to those of skill in the art in combination with the polypeptide and nucleic acid sequences provided herein. The polypeptide sequences can be used to determine the appropriate nucleic acid sequence that encodes a particular polypeptide disclosed herein. The nucleic acid sequences can be optimized to reflect the particular codon "preferences" in various expression systems according to standard methods well known to those of skill in the art.

[0134] According to certain related embodiments, there are provided recombinant host cells comprising one or more constructs described herein (e.g., vectors comprising a nucleic acid encoding a Wnt surrogate molecule or polypeptide thereof), as well as methods of producing the encoded product, comprising expressing it from the encoding nucleic acid therefor. Expression can be conveniently achieved by culturing recombinant host cells comprising the nucleic acid under appropriate conditions. Once produced by expression, the antibody or antigen-binding fragment thereof can be isolated and / or purified using any suitable technique and then used as desired.

[0135] Polypeptides, as well as encoding nucleic acid molecules and vectors, can be, for example, isolated and / or purified from their natural environment in substantially pure or homogeneous form, or, in the case of nucleic acids, free or substantially free of nucleic acid or gene of origin other than the sequence encoding the polypeptide having the desired function. Nucleic acids can include DNA or RNA and can be wholly or partially synthetic. Reference to a nucleotide sequence given herein encompasses DNA molecules having the specified sequence, unless the context requires otherwise, and also encompasses RNA molecules having the specified sequence in which U is substituted for T.

[0136] Systems for cloning and expressing polypeptides in a variety of different host cells are well known. Suitable host cells include bacteria, mammalian cells, yeast, and baculovirus systems. Mammalian cell lines available in the art for heterologous polypeptide expression include Chinese hamster ovary cells, HeLa cells, baby hamster kidney cells, NSO mouse melanoma cells, and many others. A common and preferred bacterial host is E. coli.

[0137] Expression of polypeptides (e.g., antibodies and antigen-binding fragments thereof) in prokaryotic cells such as E. coli is well established in the art. For a review, see Pluckthun, A. Bio / Technology 9:545-551 (1991). Expression in eukaryotic cells in culture is also available to those skilled in the art as an option for producing antibodies or antigen-binding fragments thereof. For recent reviews, see, e.g., Ref, ME (1993) Curr. Opinion Biotech. 4:573-576; Trill JJ et al. (1995) Curr. Opinion Biotech 6:553-560.

[0138] Suitable vectors can be selected or constructed, containing appropriate control sequences, including promoter sequences, termination sequences, polyadenylation sequences, enhancer sequences, marker genes, and other sequences as appropriate. Vectors can be plasmids, viruses (e.g., phage), or phagemids, as appropriate. For further details, see, for example, Molecular Cloning: a Laboratory Manual: 2nd Edition. See Current Protocols in Molecular Biology, Second Edition, Ausubel et al. eds., John Wiley & Sons, 1992, or any subsequent revision. For the manipulation of nucleic acids, e.g., in preparing nucleic acid constructs, mutagenesis, sequencing, DNA introduction into cells and gene expression, and analysis of proteins, many known techniques and protocols are described in detail in Current Protocols in Molecular Biology, Second Edition, Ausubel et al. eds., John Wiley & Sons, 1992, or any subsequent revision.

[0139] The term "host cell" is used to refer to a cell into which a nucleic acid sequence encoding one or more of the polypeptides described herein has been introduced or can be introduced, and which further expresses or is capable of expressing a selected gene of interest (e.g., a gene encoding any of the polypeptides described herein). The term includes the progeny of the parent cell, whether or not the progeny is identical in morphology or genetic make-up to the original parent, so long as the selected gene is present. Thus, methods involving the introduction of such nucleic acid into a host cell are also contemplated. This introduction can use any available technique. For eukaryotic cells, suitable techniques can include calcium phosphate transfection, DEAE-dextran, electroporation, liposome-mediated transfection, and transduction with retroviruses or other viruses (e.g., vaccinia virus, or baculovirus in the case of insect cells). For bacterial cells, suitable techniques can include calcium chloride transformation, electroporation, and transfection with bacteriophage. After introduction, expression from the nucleic acid can be caused or allowed, for example, by culturing the host cell under conditions for gene expression. In one embodiment, the nucleic acid is integrated into the genome (e.g., chromosome) of the host cell. Integration can be facilitated by the inclusion of sequences that facilitate recombination with the genome, according to standard techniques.

[0140] The present invention also provides, in certain embodiments, methods that include using constructs as described above in an expression system to express a particular polypeptide, such as a Wnt mimetic molecule as described herein. The term "transduction" is used to refer to the transfer of genes from one bacterium to another, usually by phage. It also refers to the acquisition and transfer of eukaryotic sequences by retroviruses. The term "transfection" refers to the uptake of exogenous or foreign DNA by a cell, and a cell is "transfected" when the foreign DNA is introduced inside the cell membrane. Several transfection techniques are known in the art and disclosed herein. See, for example, Graham et al., 1973, Virology 52:456; Sambrook et al., 2001, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2003, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2004, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2005, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2006, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2007, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2009, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2010, MOLECULAR CLONING, A LABORATORY MANUAL, Cold Spring Harbor Laboratories; Davis et al., 2011, MOLECULAR CLONING, A See, e.g., E. et al., 1986, BASIC METHODS IN MOLECULAR BIOLOGY, Elsevier; and Chu et al., 1981, Gene 13:197. Such techniques can be used to introduce one or more foreign DNA moieties into a suitable host cell.

[0141] As used herein, the term "transformation" refers to a change in the genetic characteristics of a cell, and a cell is transformed if it has been modified to contain new DNA. For example, a cell is transformed if it has been genetically modified from its native state. After transfection or transduction, the transforming DNA may recombine with the cell's DNA by physically integrating into the cell's chromosome, may be maintained transiently as an episomal element without being replicated, or may replicate independently as a plasmid. A cell is considered stably transformed if the DNA replicates with cell division. The terms "natural" or "native" when used in conjunction with biological materials such as nucleic acid molecules, polypeptides, host cells, and the like, refer to materials found in nature and not manipulated by humans. Similarly, as used herein, the terms "non-natural" or "non-native" refer to materials not found in nature and structurally modified or synthesized by humans.

[0142] The terms "polypeptide", "protein" and "peptide", as well as "glycoprotein", are used interchangeably and refer to a polymer of amino acids not limited to any particular length. The terms do not exclude modifications such as myristylation, sulfation, glycosylation, phosphorylation, and the addition or deletion of a signal sequence. The term "polypeptide" or "protein" refers to one or more chains of amino acids, each chain comprising amino acids covalently linked by peptide bonds, and the polypeptide or protein may include multiple chains non-covalently and / or covalently linked together by peptide bonds having the sequence of a native protein, i.e., a protein produced by a cell that is naturally occurring and not specifically recombinant, and may include molecules having the amino acid sequence of a native protein or molecules having deletions from, additions to, and / or substitutions of one or more amino acids of the native sequence. The terms "polypeptide" and "protein" specifically encompass Wnt surrogate molecules, Fzd-binding regions thereof, LRP5 / 6-binding regions thereof, antibodies and antibody-binding fragments thereof that bind to the Fzd receptors or the LRP5 or LRP6 receptors disclosed herein, or sequences having one or more amino acid deletions, additions, and / or substitutions of any of these polypeptides. Thus, a "polypeptide" or "protein" can include both a single amino acid chain (referred to as a "monomer") and multiple amino acid chains (referred to as a "multimer").

[0143] The term "isolated protein," "isolated Wnt surrogate molecule," or "isolated antibody" as referred to herein means that the subject protein, Wnt surrogate molecule, or antibody is (1) free of at least some other proteins with which it would typically be found in nature, (2) essentially free of other proteins from the same source (e.g., from the same species), (3) expressed by cells from a different species, (4) separated from at least about 50% of the polynucleotides, lipids, carbohydrates, or other materials with which it is naturally associated, (5) not associated (by covalent or non-covalent interactions) with portions of proteins with which it is naturally associated, (6) operably associated (by covalent or non-covalent interactions) with polypeptides with which it is not naturally associated, or (7) not occurring in nature. Such isolated proteins can be encoded by genomic DNA, cDNA, mRNA, or other RNA, or can be of synthetic origin, or any combination thereof. In certain embodiments, isolated proteins can include natural and / or artificial polypeptide sequences. In certain embodiments, an isolated protein is substantially free of proteins or polypeptides or other contaminants found in its natural environment that would interfere with its use (therapeutic, diagnostic, prophylactic, research, or other use).

[0144] Amino acid sequence modification(s) of any of the polypeptides described herein (e.g., Wnt surrogate molecules or Fzd-binding or LRP5 / 6-binding regions thereof) are contemplated. For example, it may be desirable to improve the binding affinity and / or other biological properties of the Wnt surrogate molecule. For example, amino acid sequence variants of the Wnt surrogate molecule can be prepared by introducing appropriate nucleotide changes into a polynucleotide encoding an antibody or a chain thereof, or by peptide synthesis. Such modifications include, for example, deletions from, and / or insertions into, and / or substitutions of residues within the amino acid sequence of the antibody. Any combination of deletions, insertions, and substitutions can be made to arrive at the final Wnt surrogate molecule, provided that the final construct possesses the desired characteristics (e.g., high affinity binding to one or more Fzd and / or LRP5 / 6 receptors). Amino acid changes may also alter post-translational processing of the antibody, for example, resulting in changes in the number or placement of glycosylation sites. Any of the variations and modifications described above for the polypeptides of the present invention may be included in the antibodies of the present invention.

[0145] The present disclosure provides variants of any of the polypeptides disclosed herein (e.g., Wnt surrogate molecules or Fzd-binding or LRP5 / 6-binding regions thereof, or antibodies or antigen-binding fragments thereof). In certain embodiments, the variants have at least 90%, at least 95%, at least 98%, or at least 99% identity to the polypeptides disclosed herein. In certain embodiments, such variant polypeptides bind to one or more Fzd receptors and / or to one or more LRP5 / 6 receptors at least about 50%, at least about 70%, and in certain embodiments at least about 90% of the Wnt surrogate molecules specifically described herein. In further embodiments, such variant Wnt surrogate molecules bind to one or more Fzd receptors and / or to one or more LRP5 / 6 receptors with higher affinity than the Wnt surrogate molecules described herein, e.g., bind quantitatively at least about 105%, 106%, 107%, 108%, 109%, or 110% of the antibody sequences specifically described herein.

[0146] In certain embodiments, the Wnt surrogate molecule or binding region thereof (e.g., Fab, scFv, or VHH or sdAb) can comprise: a) a heavy chain variable region comprising: i. a CDR1 region having an amino acid sequence identical to the heavy chain CDR1 region of a selected antibody described herein; ii. a CDR2 region having an amino acid sequence identical to the heavy chain CDR2 region of the selected antibody; and iii. a CDR3 region having an amino acid sequence identical to the heavy chain CDR3 region of the selected antibody; and / or b) a light chain variable region comprising: i. a CDR1 region having an amino acid sequence identical to the light chain CDR1 region of the selected antibody; ii. a CDR2 region having an amino acid sequence identical to the light chain CDR2 region of the selected antibody; and iii. a CDR3 region having an amino acid sequence identical to the light chain CDR3 region of the selected antibody; wherein the antibody specifically binds to a selected target (e.g., one or more Fzd receptors or LRP5 or LRP6 receptors). In further embodiments, the antibody or antigen-binding fragment thereof is a variant antibody or antigen-binding fragment thereof, which comprises heavy and light chains identical to the selected antibody except for up to 8, 9, 10, 11, 12, 13, 14, 15 or more amino acid substitutions in the CDR regions of the VH and VL regions. In this regard, there may be 1, 2, 3, 4, 5, 6, 7, 8, or in certain embodiments 9, 10, 11, 12, 13, 14, 15 or more amino acid substitutions in the CDR regions of the selected antibody. The substitutions may be within the CDRs in either the VH and / or VL regions. (See, e.g., Muller, 1998, Structure 6:1153-1167). In certain embodiments, the Wnt surrogate molecule or binding region thereof (e.g., Fab, scFv, or VHH or sdAb) may have a) a heavy chain variable region having an amino acid sequence that is at least 80% identical, at least 95% identical, at least 90%, at least 95%, or at least 98% or 99% identical to a heavy chain variable region of an antibody or antigen-binding fragment thereof described herein; and / or b) a light chain variable region having an amino acid sequence that is at least 80% identical, at least 85%, at least 90%, at least 95%, or at least 98% or 99% identical to a light chain variable region of an antibody or antigen-binding fragment thereof described herein. Exemplary amino acid sequences of antigen-binding fragments thereof are set forth in SEQ ID NOs: 1-128.

[0147] A polypeptide has a certain percentage of "sequence identity" to another polypeptide, meaning that when aligned, the percentage of amino acids are the same when comparing the two sequences. Sequence similarity can be determined in several different ways. To determine sequence identity, sequences can be aligned using methods and computer programs, including BLAST, available on the World Wide Web at ncbi.nlm.nih.gov / BLAST / . Another alignment algorithm is FASTA, available in the Genetics Computing Group (GCG) package from Oxford Molecular Group, Inc., a wholly owned subsidiary of Madison, Wis., USA. Other alignment techniques are described in Methods in Enzymology, vol. 266: Computer Methods for Macromolecular Sequence Analysis (1996), ed. Doolittle, Academic Press, Inc. (a division of Harcourt Brace & Co., San Diego, Calif., USA). Of particular interest are alignment programs that permit gaps in sequences. The Smith-Waterman is one type of algorithm that permits gaps in sequence alignments. See Meth. Mol. Biol. 70:173-187 (1997). The GAP program, which uses the Needleman and Wunsch alignment method, can also be used to align sequences. See J. Mol. Biol. 48:443-453 (1970).

[0148] Of interest is the BestFit program, which determines sequence identity using the local homology algorithm of Smith and Waterman (Advances in Applied Mathematics 2:482-489 (1981)). Gap creation penalties generally range from 1 to 5, usually 2 to 4, and in many embodiments are 3. Gap extension penalties generally range from about 0.01 to 0.20, and in many cases are 0.10. The program has default parameters determined by the input sequences to be compared. Sequence identity is preferably determined using the default parameters determined by the program. This program is also available from the Genetics Computing Group (GCG) package from Madison, Wis., USA.

[0149] Another program of interest is the FastDB algorithm. FastDB is described in Current Methods in Sequence Comparison and Analysis, Macromolecule Sequencing and Synthesis, Selected Methods and Applications, pp. 127-149, 1988, Alan R. Liss, Inc. Percent sequence identity is calculated by FastDB based on the following parameters: mismatch penalty: 1.00; gap penalty: 1.00; gap size penalty: 0.33; and linkage penalty: 30.0.

[0150] In certain embodiments, a Wnt surrogate molecule or binding region thereof (e.g., Fab, scFv, or VHH or sdAb) can comprise: a) a heavy chain variable region comprising: i. a CDR1 region having an amino acid sequence identical to the heavy chain CDR1 region of a selected antibody described herein; ii. a CDR2 region having an amino acid sequence identical to the heavy chain CDR2 region of the selected antibody; and iii. a CDR3 region having an amino acid sequence identical to the heavy chain CDR3 region of the selected antibody; and b) a light chain variable region comprising: i. a CDR1 region having an amino acid sequence identical to the light chain CDR1 region of the selected antibody; ii. a CDR2 region having an amino acid sequence identical to the light chain CDR2 region of the selected antibody; and iii. a CDR3 region having an amino acid sequence identical to the light chain CDR3 region of the selected antibody; wherein the antibody specifically binds to a selected target (e.g., a Fzd receptor such as Fzd1). In further embodiments, the antibody or antigen-binding fragment thereof is a variant antibody, which comprises heavy and light chains identical to the selected antibody except for up to 8, 9, 10, 11, 12, 13, 14, 15 or more amino acid substitutions in the CDR regions of the VH and VL regions. In this regard, there may be 1, 2, 3, 4, 5, 6, 7, 8, or in certain embodiments 9, 10, 11, 12, 13, 14, 15 or more amino acid substitutions in the CDR regions of the selected antibody. The substitutions may be within the CDRs in either the VH and / or VL regions. (See, e.g., Muller, 1998, Structure 6:1153-1167). Determination of the three-dimensional structure of a representative polypeptide (e.g., a variant Fzd-binding region or LRP5 / 6-binding region of a Wnt surrogate molecule provided herein) can be performed through routine methodologies such that one or more amino acid substitutions, additions, deletions, or insertions with selected natural or unnatural amino acids can be virtually modeled for the purpose of determining whether the structural variants so derived retain the space-filling properties of the species disclosed herein. For example, Donate et al.,1994 Prot.Sci.3:2378;Bradley et al.,Science 309:1868-1871(2005);Schueler-Furman et al.,Science 310:638(2005);Dietz et al.,Proc.Nat.Acad.Sci.USA See 103:1244 (2006); Dodson et al., Nature 450:176 (2007); Qian et al., Nature 450:259 (2007); Raman et al. Science 327:1014-1018 (2010). Some additional non-limiting examples of computer algorithms that may be used in these and related embodiments, for example, for rational design of binding regions, include VMD, a molecular visualization program for displaying, animating, and analyzing large biomolecular systems using 3D graphics and built-in scripts (see the website of the Theoretical and Computational Biophysics Group, University of Illinois at Urbana-Champagne: ks.uiuc.edu / Research / vmd / ). Numerous other computer programs that allow for the determination of atomic dimensions (van der Waals radii) from space-filling models of energy-minimized conformations are known in the art and available to those of skill in the art, including GRID, which determines regions of high affinity for different chemical groups and attempts to enhance binding, Monte Carlo studies that calculate mathematical alignments, and CHARMM (Brooks et al., 2002) which evaluates force field calculations and analysis. (1983) J. Comput. Chem. 4:187-217) and AMBER (Weiner et al (1981) J. Comput. Chem. 106:765) (Eisenfield et al. al.(1991)Am.J.Physiol.261:C376-386;Lybrand(1991)J.Pharm.Belg.46:49-54;Froimowitz(1990)Biotechniques 8:640-644;Burbam et al.(1990)Proteins 7:99-111; see also Pedersen (1985) Environ. Health Perspect. 61:185-190; and Kini et al. (1991) J. Biomol. Structure. Dyn. 9:475-488). A variety of suitable computational computer programs are also commercially available (eg, Schrodinger, Munich, Germany).

[0151] composition Also disclosed are pharmaceutical compositions comprising the Wnt surrogate molecules described herein and one or more pharma- ceutically acceptable diluents, carriers, or excipients. In certain embodiments, the pharmaceutical compositions further comprise one or more Wnt or Norrin polypeptides.

[0152] In further embodiments, pharmaceutical compositions are also disclosed that include a polynucleotide comprising a nucleic acid encoding a Wnt surrogate molecule as described herein and one or more pharma- ceutically acceptable diluents, carriers, or excipients. In certain embodiments, the pharmaceutical composition further comprises one or more polynucleotides comprising a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the polynucleotide is a DNA or mRNA (e.g., a modified mRNA). In certain embodiments, the polynucleotide is a modified mRNA further comprising a 5' cap sequence and / or a 3' tailing sequence (e.g., a polyA tail). In other embodiments, the polynucleotide is an expression cassette that includes a promoter operably linked to the coding sequence. In certain embodiments, the nucleic acid sequence encoding the Wnt surrogate molecule and the nucleic acid sequence encoding the Wnt polypeptide or the Norrin polypeptide are present in the same polynucleotide.

[0153] In further embodiments, pharmaceutical compositions are also disclosed that include an expression vector (e.g., a viral vector) that includes a polynucleotide that includes a nucleic acid encoding a Wnt surrogate molecule, and one or more pharma- ceutically acceptable diluents, carriers, or excipients. In certain embodiments, the pharmaceutical composition further includes an expression vector (e.g., a viral vector) that includes a polynucleotide that includes a nucleic acid sequence that encodes a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the nucleic acid sequence that encodes a Wnt surrogate molecule and the nucleic acid sequence that encodes a Wnt polypeptide or a Norrin polypeptide are present in the same polynucleotide (e.g., an expression cassette).

[0154] The present invention further contemplates a pharmaceutical composition comprising a cell comprising an expression vector comprising a polynucleotide comprising a promoter operably linked to a nucleic acid encoding a Wnt surrogate molecule, and one or more pharma- ceutically acceptable diluents, carriers, or excipients. In certain embodiments, the pharmaceutical composition further comprises a cell comprising an expression vector comprising a polynucleotide comprising a promoter operably linked to a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the nucleic acid sequence encoding a Wnt surrogate molecule and the nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide are present in the same polynucleotide (e.g., expression cassette) and / or in the same cell. In certain embodiments, the cell is a xenogeneic cell or an autologous cell obtained from the subject to be treated. In certain embodiments, the cell is a stem cell (e.g., an adipose-derived stem cell or a hematopoietic stem cell).

[0155] The present disclosure contemplates a pharmaceutical composition comprising a first molecule for delivering a Wnt surrogate molecule as a first active agent, and a second molecule for delivering a Wnt polypeptide or a Norrin polypeptide. The first and second molecules can be the same type of molecule or different types of molecules. For example, in certain embodiments, the first and second molecules can each be independently selected from the following types of molecules: polypeptides, small organic molecules, nucleic acids (optionally DNA or mRNA, optionally modified RNA) encoding the first and second active agents, vectors (optionally expression vectors or viral vectors) comprising nucleic acid sequences encoding the first or second active agents, and cells (optionally expression cassettes) comprising nucleic acid sequences encoding the first or second active agents.

[0156] The subject molecules, alone or in combination, can be combined with pharma- ceutically acceptable carriers, diluents, excipients, and reagents that are generally safe, non-toxic, and useful for preparing the desired formulations, including excipients that are acceptable for use in mammals (e.g., humans or primates). Such excipients can be solid, liquid, semi-solid, or, in the case of aerosol compositions, gaseous. Examples of such carriers, diluents, and excipients include, but are not limited to, water, saline, Ringer's solution, dextrose solution, and 5% human serum albumin. Additional active compounds can also be incorporated into the formulation. The solution or suspension used in the formulation may include sterile diluents such as water for injection, saline, fixed oils, polyethylene glycol, glycerin, propylene glycol, or other synthetic solvents; antibacterial compounds such as benzyl alcohol or methylparaben; antioxidants such as ascorbic acid or sodium bisulfite; chelating compounds such as ethylenediaminetetraacetic acid (EDTA); buffers such as acetic acid, citric acid, or phosphoric acid; surfactants to prevent aggregation such as Tween 20; and compounds for adjusting osmotic pressure such as sodium chloride or dextrose. pH can be adjusted using acids or bases such as hydrochloric acid or sodium hydroxide. In certain embodiments, the pharmaceutical composition is sterile.

[0157] The pharmaceutical compositions may further include sterile aqueous solutions or dispersions, and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. For intravenous administration, suitable carriers include physiological saline, bacteriostatic water, or phosphate buffered saline (PBS). In some cases, the composition should be sterile and liquid so that it can be taken up into a syringe or delivered from a syringe to a subject. In certain embodiments, the composition is stable under the conditions of manufacture and storage, and preserved against the contaminating action of microorganisms, such as bacteria and fungi. The carrier can be, for example, a solvent or dispersion medium, for example, a solvent or dispersion medium containing water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and the like), and suitable mixtures thereof. Proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion, and by the use of surfactants. Prevention of the action of microorganisms can be achieved by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents in the composition, for example, sugars, polyalcohols such as mannitol, sorbitol, sodium chloride, etc. Prolonged absorption of the internal composition can be brought about by including in the composition an agent which delays absorption, for example, aluminum monostearate and gelatin.

[0158] Sterile solutions can be prepared by incorporating the required amount of anti-Fzd antibody or its antigen-binding fragment (or encoding polynucleotide or cells containing it) in a suitable solvent with one or a combination of ingredients listed above as needed, followed by filter sterilization. In general, dispersions are prepared by incorporating the active compound into a sterile vehicle containing a basic dispersion medium and the required other ingredients listed above. In the case of sterile powders for the preparation of sterile injectable solutions, methods of preparation include vacuum drying and freeze-drying, which yield a powder containing the active ingredient and any additional desired ingredient from a previously sterile-filtered solution.

[0159] In one embodiment, the pharmaceutical composition is prepared with a carrier that protects the antibody or antigen-binding fragment thereof against rapid elimination from the body (e.g., controlled release formulations, including implants and microencapsulated delivery systems). Biodegradable, biocompatible polymers, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid, can be used. Methods for preparing such formulations will be apparent to those skilled in the art. Materials can also be commercially obtained. Liposomal suspensions can also be used as pharma-ceutically acceptable carriers. These can be prepared according to methods known to those skilled in the art.

[0160] To facilitate administration and ensure uniformity of dosage, it may be advantageous to formulate pharmaceutical compositions in dosage unit form.As used herein, dosage unit form refers to a physically discrete unit suitable for a unitary dosage of the subject to be treated, each unit containing a predetermined amount of active antibody or its antigen-binding fragment calculated to produce a desired effect together with the required pharmaceutical carrier.The specifications of dosage unit form are determined by and directly depend on the characteristics specific to the antibody or its antigen-binding fragment, the particular therapeutic effect to be achieved, and the inherent constraints of the technical field of formulating such active antibody or its antigen-binding fragment for the treatment of an individual.

[0161] The pharmaceutical compositions can be included in a container, pack, or dispenser, e.g., a syringe, e.g., a prefilled syringe, together with instructions for administration.

[0162] The pharmaceutical compositions of the present invention include any pharma- ceutically acceptable salts, esters, or salts of such esters, or any other compounds that are capable of providing (directly or indirectly) a biologically active antibody or antigen-binding fragment thereof when administered to an animal, including a human.

[0163] The present invention includes pharma- ceutically acceptable salts of the Wnt surrogate molecules described herein. The term "pharma- ceutically acceptable salts" refers to physiologically and pharma- ceutical acceptable salts of the compounds of the present invention, i.e., salts that retain the desired biological activity of the parent compound and do not impart undesired toxicological effects thereto. Various pharma- ceutical acceptable salts are known in the art and are described, for example, in "Remington's Pharmaceutical Sciences", 17th edition, Alfonso R. Gennaro (Ed.), Mark Publishing Company, Easton, PA, USA, 1985 (and more recent editions), "Encyclopaedia of Pharmaceutical Technology", 3rd edition, James Swarbrick (Ed.), Informa Healthcare USA (Inc.), NY, USA, 2007, and J.Pharm.Sci. 66:2 (1977). For a review of suitable salts, see also “Handbook of Pharmaceutical Salts: Properties, Selection, and Use” by Stahl and Wermuth (Wiley-VCH, 2002).

[0164] Pharmaceutically acceptable base addition salts are formed with metals or amines, such as alkali and alkaline earth metals, or organic amines. Metals used as cations include sodium, potassium, magnesium, calcium, and the like. Amines include N-N'-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, dicyclohexylamine, ethylenediamine, N-methylglucamine, and procaine (see, for example, Berge et al., "Pharmaceutical Salts," J. Pharma Sci., 1977, 66, 119). The base addition salts of the aforementioned acidic compounds are prepared in a conventional manner by contacting the free acid form with a sufficient amount of the desired base to produce the salt. The free acid form can be regenerated in a conventional manner by contacting the salt form with an acid and isolating the free acid. The free acid forms differ somewhat from the respective salt forms in certain physical properties (e.g., solubility in polar solvents), but otherwise the salts are equivalent to the respective free acids for purposes of this invention.

[0165] In some embodiments, the pharmaceutical compositions provided herein comprise a therapeutically effective amount of a Wnt surrogate molecule described herein or a pharma- ceutical acceptable salt thereof in admixture with a pharma- ceutical acceptable carrier, diluent, and / or excipient (e.g., saline, phosphate buffered saline, phosphate, and amino acids, polymers, polyols, sugars, buffers, preservatives, and other proteins). Exemplary amino acids, polymers, sugars, and the like are octylphenoxypolyethoxyethanol compounds, polyethylene glycol monostearate compounds, polyoxyethylene sorbitan fatty acid esters, sucrose, fructose, dextrose, maltose, glucose, mannitol, dextran, sorbitol, inositol, galactitol, xylitol, lactose, trehalose, bovine or human serum albumin, citrate, acetate, Ringer's solution, Hank's solution, cysteine, arginine, carnitine, alanine, glycine, lysine, valine, leucine, polyvinylpyrrolidone, polyethylene, and glycol. Preferably, the formulation is stable at 4° C. for at least 6 months.

[0166] In some embodiments, the pharmaceutical compositions provided herein comprise a buffer, including, for example, phosphate buffered saline (PBS) or sodium phosphate / sodium sulfate, Tris buffer, glycine buffer, sterile water, and other buffers known to those of skill in the art, such as those described by Good et al. (1966) Biochemistry 5: 467. The pH of the buffer can be in the range of 6.5 to 7.75, preferably 7 to 7.5, and most preferably 7.2 to 7.4.

[0167] How to use The present disclosure also provides a method for using the Wnt surrogate molecules disclosed herein, for example, to regulate the Wnt signaling pathway, for example, to increase Wnt signaling, and a method for administering the Wnt surrogate molecules disclosed herein in various therapeutic settings. Provided herein is a method of treatment using the Wnt surrogate molecules. In one embodiment, the Wnt surrogate molecules are provided to a subject having a disease associated with inappropriate or deregulated Wnt signaling, for example, increased or decreased Wnt signaling.

[0168] Increasing Wnt signaling pathway and related therapeutic methods In certain embodiments, the Wnt surrogate molecule can be used to increase Wnt signaling in tissue or cell.Thus, in some aspects, the present invention provides a method for increasing or increasing Wnt signaling in tissue or cell, comprising contacting the tissue or cell with an effective amount of the Wnt surrogate molecule disclosed herein or a pharma-ceutically acceptable salt thereof, wherein the Wnt surrogate molecule is a Wnt signaling pathway agonist.In some embodiments, the contacting is performed in vitro, ex vivo, or in vivo.In certain embodiments, the cell is a cultured cell, and the contacting is performed in vitro.In certain embodiments, the method further comprises contacting the tissue or cell with one or more Wnt polypeptides or Norrin polypeptides.

[0169] In a related aspect, the present invention provides a method for increasing Wnt signaling in a tissue or cell, comprising contacting the tissue or cell with an effective amount of a polynucleotide comprising a Wnt surrogate molecule disclosed herein. In certain embodiments, the target tissue or cell is also contacted with a polynucleotide comprising a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the polynucleotide is DNA or mRNA (e.g., modified mRNA). In certain embodiments, the polynucleotide is a modified mRNA further comprising a 5' cap sequence and / or a 3' tailing sequence (e.g., polyA tail). In other embodiments, the polynucleotide is an expression cassette comprising a promoter operably linked to the coding sequence. In certain embodiments, the nucleic acid sequence encoding the Wnt surrogate molecule and the nucleic acid sequence encoding the Wnt polypeptide or the Norrin polypeptide are present in the same polynucleotide.

[0170] In a related aspect, the present invention provides a method for increasing Wnt signaling in a tissue or cell, comprising contacting the tissue or cell with an effective amount of a vector comprising a nucleic acid sequence encoding a Wnt surrogate molecule. In certain embodiments, the tissue or cell is also contacted with a vector comprising a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the vector is an expression vector and can comprise a promoter operably linked to the nucleic acid sequence. In certain embodiments, the vector is a viral vector. In certain embodiments, the nucleic acid sequence encoding a Wnt surrogate molecule and the nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide are present in the same vector (e.g., the same expression cassette).

[0171] In a related aspect, the present invention provides a method for increasing Wnt signaling in a tissue, comprising contacting the tissue with an effective amount of a cell comprising a nucleic acid sequence encoding a Wnt surrogate molecule of the present invention. In certain embodiments, the tissue is also contacted with a cell comprising a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the nucleic acid sequence encoding a Wnt surrogate molecule and the nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide are present in the same cell. In certain embodiments, the cell is a heterologous cell or an autologous cell obtained from the subject to be treated. In certain embodiments, the cell is transduced with a vector comprising an expression cassette encoding a Wnt surrogate molecule or a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the cell is a stem cell (e.g., an adipose-derived stem cell or a hematopoietic stem cell).

[0172] The Wnt surrogate molecules disclosed herein can be used to treat diseases, disorders, or conditions, for example, by increasing Wnt signaling in targeted cells, tissues, or organs.Thus, in some aspects, the present invention provides a method for treating a disease or condition in a subject in need thereof, for example, a disease or disorder associated with reduced Wnt signaling, or a disease or disorder for which increased Wnt signaling is believed to provide therapeutic benefit, comprising contacting the subject with an effective amount of a composition of the present disclosure.In certain embodiments, the composition is a pharmaceutical composition comprising any of the following: a Wnt surrogate molecule; a polynucleotide, for example, DNA or mRNA, optionally modified mRNA, comprising a nucleic acid sequence encoding a Wnt surrogate molecule; a vector, for example, an expression vector or a viral vector, comprising a nucleic acid sequence encoding a Wnt surrogate molecule; or a cell comprising a nucleic acid sequence encoding a Wnt surrogate molecule, for example, a cell transduced with an expression vector or a viral vector encoding a Wnt surrogate molecule.In certain embodiments, the disease or condition is a pathological disease or disorder, or injury (for example, injury resulting from wounding). In certain embodiments, the wound may be the result of another therapeutic treatment. In certain embodiments, the disease or condition involves poor tissue repair, healing, or regeneration, or would benefit from increased tissue repair, healing, or regeneration. In some embodiments, the contacting occurs in vivo, i.e., the subject composition is administered to the subject.

[0173] In certain embodiments, the method further comprises contacting the subject with a pharmaceutical composition comprising one or more Wnt or Norrin polypeptides. The present disclosure contemplates contacting the subject with a first molecule for delivering a Wnt surrogate molecule as a first active agent and a second molecule for delivering a Wnt or Norrin polypeptide. The first and second molecules may be the same type of molecule or different types of molecules. For example, in certain embodiments, the first and second molecules may each be independently selected from the following types of molecules: polypeptides, small organic molecules, nucleic acids (optionally DNA or mRNA, optionally modified RNA) encoding the first and second active agents, vectors (optionally expression vectors or viral vectors) comprising nucleic acid sequences encoding the first or second active agents, and cells (optionally expression cassettes) comprising nucleic acid sequences encoding the first or second active agents.

[0174] In a related aspect, the present invention provides a method for treating a disease or condition, e.g., a disease or disorder associated with reduced Wnt signaling or a disease or disorder in which increased Wnt signaling is believed to provide a therapeutic benefit, comprising contacting a subject in need thereof with a pharmaceutical composition comprising an effective amount of a polynucleotide comprising a nucleic acid sequence encoding a Wnt surrogate molecule disclosed herein. In certain embodiments, the subject is also contacted with a pharmaceutical composition comprising an effective amount of a polynucleotide comprising a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the polynucleotide is DNA or mRNA (e.g., modified mRNA). In certain embodiments, the polynucleotide is a modified mRNA further comprising a 5' cap sequence and / or a 3' tailing sequence (e.g., polyA tail). In other embodiments, the polynucleotide is an expression cassette comprising a promoter operably linked to the coding sequence. In certain embodiments, the nucleic acid sequence encoding the Wnt surrogate molecule and the nucleic acid sequence encoding the Wnt polypeptide or the Norrin polypeptide are present within the same polynucleotide.

[0175] In a related aspect, the present invention provides a method for treating a disease or condition, such as a disease or disorder associated with reduced Wnt signaling or a disease or disorder for which increased Wnt signaling is believed to provide therapeutic benefit, comprising contacting a subject in need thereof with a pharmaceutical composition comprising an effective amount of a vector comprising a nucleic acid sequence encoding a Wnt surrogate molecule. In certain embodiments, the subject is also contacted with a pharmaceutical composition comprising an effective amount of a vector comprising a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the vector is an expression vector and may comprise a promoter operably linked to the nucleic acid sequence. In certain embodiments, the vector is a viral vector. In certain embodiments, the nucleic acid sequence encoding a Wnt surrogate molecule and the nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide are present in the same vector (e.g., the same expression cassette).

[0176] In a related aspect, the present invention provides a method for treating a disease or condition, such as a disease or disorder associated with reduced Wnt signaling or a disease or disorder for which increased Wnt signaling is believed to provide a therapeutic benefit, comprising contacting a subject in need thereof with a pharmaceutical composition comprising an effective amount of a cell comprising a nucleic acid sequence encoding a Wnt surrogate molecule. In certain embodiments, the subject is also contacted with a cell comprising a nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the nucleic acid sequence encoding a Wnt surrogate molecule and the nucleic acid sequence encoding a Wnt polypeptide or a Norrin polypeptide are present in the same cell. In certain embodiments, the cell is a heterologous cell or an autologous cell obtained from the subject to be treated. In certain embodiments, the cell is transduced with a vector comprising an expression cassette encoding a Wnt surrogate molecule or a Wnt polypeptide or a Norrin polypeptide. In certain embodiments, the cell is a stem cell (e.g., an adipose-derived stem cell or a hematopoietic stem cell).

[0177] Wnt signaling plays an important role in stem cell development and maintenance. Reactivation of Wnt signaling is associated with the regeneration and repair of most tissues after injury and disease. Wnt surrogate molecules are expected to provide healing and tissue repair benefits in response to injury and disease. Causes of tissue damage and loss include, but are not limited to, aging, degeneration, genetic conditions, infection and inflammation, traumatic injury, toxin / metabolism-induced toxicity, or other pathological conditions. Wnt signals and enhancers of Wnt signals have been shown to activate adult tissue-resident stem cells. In some embodiments, the compounds of the present invention are administered for use in the treatment of diseased or damaged tissues, for use in tissue regeneration, for use in cell growth and proliferation, and / or for use in tissue engineering.

[0178] Human diseases associated with mutations in the Wnt pathway provide strong evidence for the enhancement of Wnt signaling in the treatment and prevention of disease.Preclinical in vivo and in vitro studies provide further evidence that Wnt signaling is involved in many disease states, further supporting the use of Wnt surrogate molecules in various human diseases.For example, the composition of the present invention can be used to promote or increase bone growth or regeneration, bone grafts, fracture healing, osteoporosis and osteoporotic fractures, spinal fusion, spinal cord injury including vertebral compression fractures, preoperative spinal surgery optimization, orthopedic device osseointegration, tendon-bone integration, tooth growth and regeneration, dental implants, periodontal disease, maxillofacial reconstruction, and treatment of osteonecrosis of the jaw. The compositions of the present invention may also be used in the treatment of alopecia; enhancing regeneration of sensory organs, for example, treatment of hearing loss (including inner and outer hair cell regeneration, treatment of reduced vestibular function), treatment of macular degeneration, treatment of retinopathies (including vitreous retinopathy, diabetic retinopathy, other retinal degenerative diseases), Fuchs' dystrophy, other corneal diseases, and the like; treatment of stroke, traumatic brain injury, Alzheimer's disease, multiple sclerosis, multiple dystrophy, muscle atrophy as a result of sarcopenia or cachexia, and other conditions affecting the degeneration or integrity of the blood-brain barrier. The compositions of the present invention may also be used in the treatment of oral mucositis, short bowel syndrome, inflammatory bowel disease (IBD) (including Crohn's disease (CD) and ulcerative colitis (UC), especially CD associated with fistulization), and other gastrointestinal disorders; the treatment of metabolic syndrome, dyslipidemia, the treatment of diabetes, the treatment of pancreatitis, and conditions in which extrapancreatic and endocrine pancreatic tissues have been damaged; the treatment of conditions in which enhanced epidermal regeneration is desired, such as epidermal wound healing, diabetic foot ulcers, and syndromes involving hypoplasia of the teeth, nails, or skin, in which angiogenesis would be beneficial; the treatment of myocardial infarction, coronary artery disease, and heart failure; the treatment of enhanced hematopoietic cell growth, such as enhanced hematopoietic stem cell transplantation from bone marrow, mobilized peripheral blood, immune deficiencies, graft versus host disease, and the like; the treatment of acute kidney injury, chronic kidney disease; the treatment of pulmonary disease, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (including idiopathic pulmonary fibrosis), and enhanced regeneration of lung tissue.The compositions of the invention can also be used to enhance hepatocyte regeneration (e.g., liver regeneration), treat liver cirrhosis, enhance liver transplantation, treat acute liver failure, treat chronic liver disease associated with hepatitis C or B virus infection or following antiviral drug therapy, alcoholic liver disease, including alcoholic hepatitis, non-alcoholic liver disease associated with hepatic steatosis or steatohepatitis, etc. The compositions of the invention can treat diseases and disorders, including, but not limited to, conditions in which regenerative cell growth is desired.

[0179] Human genetics with loss-of-function or gain-of-function mutations in Wnt signaling components provide strong evidence to support the enhancement of Wnt signaling for bone growth. Conditions in which enhanced bone growth is desired include, but are not limited to, fractures, grafts, periprosthetic bone growth, osteoporosis, osteoporotic fractures, spinal fusion, vertebral compression fractures, preoperative optimization for spinal surgery, osteonecrosis of the jaw, dental implants, periodontal disease, maxillofacial reconstruction, etc. Wnt surrogate molecules enhance and promote Wnt signaling, which is crucial for promoting bone regeneration. Methods for regenerating bone tissue benefit from the administration of the compounds of the present invention, which may be administered systemically or locally. In some embodiments, bone marrow cells are exposed to the molecules of the present invention, which results in the activation of stem cells in the bone marrow cells.

[0180] In some embodiments, bone regeneration is enhanced by contacting a responsive cell population (e.g., bone marrow, osteoprogenitor cells, osteoprogenitor cells, etc.) with an effective dose of the Wnt surrogate molecules disclosed herein. Methods for regenerating bone tissue benefit from administration of Wnt surrogate molecules, which may be systemic or localized. In some such embodiments, the contacting is performed in vivo. In other such embodiments, the contacting is performed ex vivo. The molecules can be localized at the site of action, for example, by loading onto a matrix that is optionally biodegradable and optionally provides sustained release of the active agent. Matrix carriers include, but are not limited to, absorbable collagen sponges, ceramics, hydrogels, polymer microspheres, nanoparticles, bone cements, and the like.

[0181] In certain embodiments, compositions comprising one or more Wnt surrogate molecules disclosed herein (or polynucleotides encoding Wnt surrogate molecules, or vectors or cells comprising polynucleotides encoding Wnt surrogate molecules) are used to treat or prevent bone diseases or disorders, including, but not limited to, any of the following, or to treat or prevent injuries associated with, but not limited to, any of the following: osteoporosis, osteoporotic fractures, fractures including vertebral compression fractures, nonunion fractures, delayed union fractures, spinal fusion, osteonecrosis, osteonecrosis of the jaw, hip, femoral head, etc., osseointegration of implants (e.g., to accelerate recovery after partial or total knee or hip replacement), osteogenesis imperfecta, bone grafts, tendon repair, maxillofacial reconstruction, dental implants, any other bone disorder or abnormality resulting from genetic disease, degeneration, aging, drugs, or injury. In one embodiment, Wnt surrogate molecules that bind Fzd1, Fzd2, and Fzd7, as well as LRP5 and / or LRP6, are used to treat or prevent any bone disease or disorder. In one embodiment, Wnt surrogate molecules that bind Fzd1, Fzd2, Fzd5, Fzd7, and Fzd8, as well as LRP5 and / or LRP6, are used to treat or prevent any bone disease or disorder. Other Fzd molecules that bind to additional Fzd receptors can also be used with the LRP5 and / or LRP6 binding agents.

[0182] In certain embodiments, the compositions and methods disclosed herein can be used to increase bone mineral density, increase bone volume (e.g., tibia and / or femur volume), increase cortical thickness (e.g., of the trabecular bone or mid-shaft of the femur), increase mineral apposition rate, increase osteoblast number and / or decrease osteoclast number (e.g., within the bone), increase bone synthesis, increase ultimate load to fracture point, improve bone resistance to fracture, decrease bone resorption, decrease bone loss associated with osteoporosis, or increase biochemical strength of bone in a subject. In one embodiment, Wnt surrogate molecules that bind Fzd1, Fzd2, and Fzd7 are used in any of these indicated uses. In one embodiment, Wnt surrogate molecules that bind Fzd1, Fzd2, Fzd5, Fzd7, and Fzd8 are used in any of these indicated uses.

[0183] Methods disclosed herein, including methods for treating or preventing bone diseases or disorders, include methods comprising providing to a subject in need thereof both a Wnt surrogate molecule and a bone resorption inhibitor, hi certain embodiments, the methods are used for the treatment of osteoporosis, optionally postmenopausal osteoporosis.

[0184] The present disclosure also provides a method for inhibiting or reducing bone resorption in a subject in need thereof, comprising providing an effective amount of a Wnt surrogate molecule to the subject, wherein the Wnt surrogate molecule is an agonist of the Wnt signaling pathway.In certain embodiments, the method further comprises providing a bone resorption inhibitor to the subject.In certain embodiments, the subject is diagnosed with or at risk of osteoporosis, optionally postmenopausal osteoporosis.Various bone resorption inhibitors are known in the art, including but not limited to those disclosed herein.

[0185] When Wnt surrogate molecule is provided to subject in combination with another therapeutic agent (e.g., bone resorption inhibitor), the two agents can be provided in the same pharmaceutical composition or different pharmaceutical compositions.The two agents can be provided to subject at the same time, at different times, for example, simultaneously, consecutively, or during overlapping or non-overlapping periods.In certain embodiments, the two agents are therapeutically active in subject during overlapping periods.

[0186] Compositions comprising one or more Wnt surrogate molecules (or polynucleotides encoding Wnt surrogate molecules, or vectors or cells comprising polynucleotides encoding Wnt surrogate molecules) disclosed herein can be used in the in vivo treatment of skeletal tissue defects. By "skeletal tissue defect" is meant a defect of bone or other bone-connective tissue at any site where restoration of bone or connective tissue is desired, regardless of how the defect occurred, for example, as a result of surgical intervention, tumor removal, ulcer, graft, fracture, or other traumatic or degenerative condition. The compositions of the present invention can be used as part of a regimen for restoring cartilage function to connective tissue, repairing abnormalities or lesions of cartilage tissue, for example, those due to degenerative wear and arthritis, trauma to the tissue, replacement of meniscus tears, meniscectomy, joint dislocation due to ligament tears, joint malalignment, fracture, or genetic disease.

[0187] Wnt surrogate molecules can also be used to treat periodontal disease. Periodontal disease is the leading cause of tooth loss and is associated with multiple systemic conditions. In some embodiments, contacting a responsive cell population enhances tooth or basal bone regeneration. In some such embodiments, the contacting is performed in vivo. In other such embodiments, the contacting is performed ex vivo, followed by transplantation of activated stem or progenitor cells. Molecules can be localized at the site of action, for example, by loading onto a matrix that is optionally biodegradable and optionally provides sustained release of the active agent. Matrix carriers include, but are not limited to, absorbable collagen sponges, ceramics, hydrogels, bone cements, polymeric microspheres, nanoparticles, and the like.

[0188] Several studies have shown that Wnt signaling and R-spondin biology can promote the regeneration of sensory hair cells in the inner ear after injury, aging, or degeneration. Loss of sensory hair cells in the inner ear associated with hearing loss or reduced vestibular function can also benefit from the compositions of the present invention. In the inner ear, the hearing organ contains the mechanosensitive hair cells required to convert sound vibrations into electrical impulses. The vestibular organ, which is composed of the semicircular canals (SSC), utricle, and saccule, also contains sensory hair cells to detect head position and movement. The compositions of the present invention can be used, for example, in injection, in matrix or other depot systems, or in other localized application to the ear, for the enhancement of hearing regeneration.

[0189] Wnt surrogate molecules can also be used to regenerate retinal tissue. In adult mammalian retinas, Müller glia cells can regenerate retinal cells, including photoreceptors, after, for example, neurotoxic injury in vivo. Wnt signaling and enhancers of Wnt signaling can promote proliferation of Müller glia-derived retinal progenitor cells after injury or during degeneration. The compositions of the present invention can also be used to regenerate tissues and other cell types within the eye. For example, age-related macular degeneration (AMD), other retinal degenerative diseases, corneal diseases, Fuchs' dystrophy, vitreoretinopathy, genetic diseases, and the like, can benefit from the compositions of the present invention. AMD is characterized by a progressive decrease in central vision and visual acuity. Fuchs' dystrophy is characterized by a progressive loss of corneal endothelial cells. Wnt signals and enhanced Wnt signals can promote regeneration of corneal endothelium, retinal epithelium, and the like within ocular tissues. In other embodiments, the compositions of the present invention can be used, for example, in injections, in matrix or other depot systems, or in other topical applications to the eye, for retinal regeneration and treatment of macular degeneration.

[0190] Specific proliferative cell populations in homeostatic regeneration of hepatocytes have been identified through lineage tracing studies, such as Axin 2 positive cells in the pericentral region. Lineage tracing studies have also identified additional potential hepatic progenitor cells, including but not limited to Lgr positive cells. Self-renewing hepatocytes, as well as other potential progenitor cell populations, including Lgr5 positive cells and Axin 2 positive cells, have been shown to be capable of regeneration in response to Wnt signaling and / or R-spondin after injury. Numerous preclinical models of acute liver injury and chronic liver disease have shown that hepatocyte recovery and regeneration benefit from Wnt signaling.

[0191] In certain embodiments, compositions comprising one or more Wnt surrogate molecules (or polynucleotides encoding Wnt surrogate molecules, or vectors or cells comprising polynucleotides encoding Wnt surrogate molecules) disclosed herein are used to promote liver regeneration, reduce fibrosis, and / or improve liver function. In certain embodiments, the compositions and methods disclosed herein are used to increase liver weight, increase liver to body weight ratio, increase the number of PCNA and pH3 positive nuclei in the liver, increase Ki67 and / or cyclin D1 expression in the liver, increase hepatocyte proliferation and / or mitosis, reduce fibrosis following chronic liver injury, or increase hepatocyte function.

[0192] In certain embodiments, the compositions of the present invention can be used in the treatment of acute liver failure, acute alcoholic liver injury, chronic liver disease with C or B viral hepatitis infection or after antiviral drug therapy, chronic alcoholic liver disease, alcoholic hepatitis, non-alcoholic fatty liver disease and non-alcoholic steatohepatitis (NASH), cirrhosis and chronic liver disease of all causes, and enhancing regeneration of liver cells.Methods for regenerating liver tissue benefit from the administration of the compounds of the present invention, and administration can be systemic or localized.Such methods include, but are not limited to, systemic administration methods and localized administration methods, for example, by injection into liver tissue, by injection into veins or blood vessels leading to the liver, localized administration by placement of sustained release formulations, etc.

[0193] In certain embodiments, compositions comprising one or more Wnt surrogate molecules (or polynucleotides encoding Wnt surrogate molecules, or vectors or cells comprising polynucleotides encoding Wnt surrogate molecules) disclosed herein are used to treat or prevent liver disease or damage, including, but not limited to, acute liver failure (all causes), chronic liver failure (all causes), cirrhosis, liver fibrosis (all causes), and / or other conditions. ), portal hypertension, alcoholic liver disease including alcoholic hepatitis, nonalcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD) (fatty liver), alcoholic hepatitis, Hepatitis C virus induced liver disease (HCV), Hepatitis B virus induced liver disease (HBV), other viral hepatitis (e.g., Hepatitis A virus induced liver disease (HAV) and Hepatitis D virus induced liver disease (HDV)), primary biliary cirrhosis, autoimmune hepatitis, liver surgery, liver injury, liver transplantation, "small for size" syndrome in liver surgery and transplantation, congenital liver disease and liver damage, genetic disease, degeneration, aging, drugs, or any other liver damage or detection due to injury.

[0194] Wnt signaling plays an important role in the regeneration of various epithelial tissues. Various epidermal conditions benefit from treatment with the compounds of the present invention. Mucositis occurs when the rapid division of epithelial cells lining the gastrointestinal tract is disrupted, leaving the mucosal tissue vulnerable to ulceration and infection. The epithelial lining portion lining the mouth, called the oral mucosa, is one of the most sensitive parts of the body and is particularly vulnerable to chemotherapy and radiation. Oral mucositis is perhaps the most common debilitating complication of cancer treatment, particularly chemotherapy and radiation. In addition, the compositions of the present invention may also benefit the treatment of short bowel syndrome, inflammatory bowel disease (IBD), or other gastrointestinal disorders. Other epidermal conditions include epidermal wound healing, diabetic foot ulcers, and syndromes related to hypoplasia of teeth, nails, or skin. The molecules of the present invention can be used in all such conditions, where regenerative cells are contacted with the compounds of the present invention. Methods for regenerating epithelial tissue benefit from the administration of the compounds of the present invention, which may be systemic or localized. Contacting can be, for example, topical (including intradermal, subcutaneous), applied to the target site, etc., in a gel, lotion, cream, etc.

[0195] Wnt signaling and the enhancement and promotion of Wnt signaling play an important role in the repair and regeneration of tissues, including the pancreas, kidney, and lung in preclinical models, in addition to the skin and gastrointestinal tract. Wnt surrogate molecules can benefit the exocrine pancreas and various disease conditions that affect the exocrine pancreas, kidney, or lung. Wnt surrogate molecules can be used in the treatment of metabolic syndrome, the treatment of diabetes, the treatment of acute or chronic pancreatitis, the treatment of exocrine pancreatic insufficiency, the treatment of acute kidney injury, the treatment of chronic kidney disease, the treatment of lung diseases, including but not limited to chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, particularly idiopathic pulmonary fibrosis (IPF), and other conditions that cause the loss of lung epithelial tissue. Methods for regenerating these tissues benefit from the administration of the compounds of the present invention, which may be administered systemically or locally.

[0196] Epidermal Wnt signaling, in cooperation with signaling via other developmental factors, is crucial for hair follicle regeneration in adults. Hair loss is a common problem, and androgenetic alopecia (often called male pattern baldness) is the most common form of hair loss in men. In some embodiments, hair follicle regeneration is enhanced by contacting a responsive cell population with the molecules of the present invention. In some such embodiments, contacting is performed in vivo. In other such embodiments, contacting is performed ex vivo. The molecule can be localized to the site of action, for example, with a topical lotion, gel, cream, etc.

[0197] Stroke, traumatic brain injury, Alzheimer's disease, multiple sclerosis, and other conditions that affect the blood-brain barrier (BBB) ​​can be treated with Wnt surrogate molecules. Angiogenesis is crucial to ensure the supply of oxygen and nutrients to many tissues throughout the body, and is particularly important to the central nervous system, as nervous tissue is sensitive to hypoxia and ischemia. CNS endothelial cells that form the BBB are highly polarized cells held together by tight junctions, and differ from endothelial cells in non-neuronal tissues in that they express specific transporters. Wnt signaling controls angiogenesis and / or function in the central nervous system. Conditions in which the BBB is compromised can benefit from the administration of the compounds of the present invention, which may be systemic or localized, for example, by direct injection, intrathecal administration, implantation of sustained release formulations, and the like. In addition, Wnt signaling is actively involved in neurogenesis and plays a role in neuroprotection after injury. The compositions of the present invention may also be used to treat spinal cord injury, other spinal cord diseases, stroke, traumatic brain injury, and the like.

[0198] Wnt signaling also plays a role in angiogenesis. Wnt surrogate molecules may be beneficial in conditions where angiogenesis is beneficial, such as the treatment of myocardial infarction, coronary artery disease, heart failure, diabetic retinopathy, and conditions resulting from genetic diseases. These methods for regenerating tissues benefit from the administration of the compounds of the present invention, which may be administered systemically or locally.

[0199] In certain embodiments, the method of the present invention promotes tissue regeneration, for example in tissue that has been damaged or has been reduced or lost tissue or cells. Loss or damage can be any event that reduces cell number, including disease or injury. For example, accidents, autoimmune disorders, side effects of treatment, or disease states are considered to constitute trauma. Tissue regeneration increases cell number in tissue, preferably allowing the connection between cells of tissue to be re-established, and more preferably allowing the functionality of tissue to be restored.

[0200] The terms "administering" or "introducing" or "providing" as used herein refer to delivering a composition to a cell, cells, tissues, and / or organs of a subject or to a subject. Such administration or introduction can occur in vivo, in vitro, or ex vivo.

[0201] In certain embodiments, the pharmaceutical composition is administered parenterally (e.g., intravenously), orally, rectally, or by injection. In some embodiments, the pharmaceutical composition is administered locally (e.g., topically or intramuscularly). In some embodiments, the composition is administered to a target tissue (e.g., to a bone, joint, ear tissue, eye tissue, gastrointestinal tract, skin, wound site, or spinal cord). The method of the present invention can be performed in vivo or ex vivo. In some embodiments, contacting a target cell or tissue with a Wnt surrogate molecule is performed ex vivo, followed by transplanting the cell or tissue (e.g., the activated stem or progenitor cell) into a subject. One skilled in the art can determine the appropriate site and route of administration based on the disease or disorder to be treated.

[0202] The dosage and dosing regimen can depend on a variety of factors readily determined by a physician, such as the nature of the disease or disorder, the characteristics of the subject, and the subject's medical history. In certain embodiments, the amount of Wnt surrogate molecule administered or provided to a subject is within the range of about 0.01 mg / kg to about 50 mg / kg, 0.1 mg / kg to about 500 mg / kg, or 0.1 mg / kg to about 50 mg / kg of the subject's body weight.

[0203] The terms "treatment", "treating" and the like are used herein broadly to mean obtaining a desired pharmacological and / or physiological effect. The effect may be prophylactic in terms of completely or partially preventing a disease or its symptoms (e.g., reducing the likelihood that a disease or its symptoms will occur in a subject) and / or therapeutic in terms of partially or completely curing a disease or adverse effects that may result from a disease. As used herein, "treatment" encompasses any treatment of a disease in a mammal, including (a) preventing a disease from occurring in a subject who may be susceptible to the disease but has not yet been diagnosed as having it; (b) inhibiting a disease, i.e., arresting its development; or (c) alleviating a disease, i.e., causing regression of a disease. Therapeutic agents (e.g., Wnt surrogate molecules) can be administered before, during, or after the onset of a disease or injury. Treatment of an ongoing disease is of particular interest if the treatment stabilizes or reduces undesirable clinical symptoms in the patient. It is desirable to perform such treatment before the affected tissue loses complete function. The subject therapy is administered during the symptomatic stage of the disease, and in some cases may be desirable after the symptomatic stage of the disease. In some embodiments, the subject method provides a therapeutic benefit (e.g., preventing the onset of a disorder, halting the progression of a disorder, reversing the progression of a disorder, etc.). In some embodiments, the subject method includes a step of detecting that a therapeutic benefit has been achieved. Those skilled in the art will understand that such measures of therapeutic efficacy are applicable to the particular disease being modified, and will recognize appropriate detection methods to use to measure therapeutic efficacy.

[0204] Other embodiments are, in part, the use of the Wnt surrogate molecules disclosed herein to promote or enhance the growth or proliferation of cells, tissues, and organoids, for example, by contacting cells or tissues with one or more Wnt surrogates, optionally in combination with Norrin or Rspondin polypeptide.In certain embodiments, cells or tissues are contacted ex vivo, in vitro, or in vivo.Such methods can be used to generate cells, tissues, or organoids for therapeutic use, for example, transplanted or grafted into a subject.Such methods can also be used to generate cells, tissues, or organoids for research use.Wnt surrogate molecules are widely applied in non-therapeutic methods, for example, in vitro research methods.

[0205] The present invention provides a method for tissue regeneration of damaged tissue (e.g., tissues discussed above), comprising administering a Wnt surrogate molecule to cells. The Wnt surrogate molecule may be administered directly to cells in vivo, or administered orally, intravenously, or by other methods known in the art to a subject, or to ex vivo cells. In some embodiments in which the Wnt surrogate molecule is administered to ex vivo cells, such cells may be transplanted into a subject before, after, or during administration of the Wnt surrogate molecule.

[0206] Wnt signaling is a key component of stem cell culture. For example, stem cell culture medium as described in WO2010 / 090513, WO2012 / 014076, Sato et al., 2011 (GASTROENTEROLOGY 2011;141:1762-1772) and Sato et al., 2009 (Nature 459,262-5). The Wnt surrogate molecule disclosed herein is suitable for use in such stem cell culture medium as a substitute for Rspondin or can be combined with Rspondin.

[0207] Therefore, in one embodiment, the present disclosure provides a method for enhancing the proliferation of stem cells, comprising contacting stem cells with one or more Wnt surrogate molecules disclosed herein.In one embodiment, the present disclosure provides a cell culture medium comprising the Wnt surrogate molecules disclosed herein.In some embodiments, the cell culture medium can be any cell culture medium already known in the art that normally comprises Wnt or Rspondin, and Wnt or Rspondin is replaced (fully or partially) or supplemented with the Wnt surrogate molecule(s) disclosed herein. For example, the medium may be as described in WO2010 / 090513, WO2012 / 014076, Sato et al., 2011 (GASTROENTEROLOGY 2011;141:1762-1772), and Sato et al., 2009 (Nature 459,262-5), which are incorporated by reference in their entireties.

[0208] Stem cell culture media often contain additional growth factors. Thus, the method may additionally include supplying the stem cells with growth factors. Growth factors commonly used in cell culture media include epidermal growth factor (EGF, (Peprotech)), transforming growth factor (TGF-alpha, Peprotech), basic fibroblast growth factor (bFGF, Peprotech), brain-derived neurotrophic factor (BDNF, R&D Systems), hepatocyte growth factor (HGF), and keratinocyte growth factor (KGF, Peprotech, also known as FGF7). EGF is a potent mitogen for a variety of cultured ectodermal and mesodermal cells, and has a profound effect on the differentiation of certain cells in vivo and in vitro, and on the differentiation of some fibroblasts in cell culture. The EGF precursor exists as a membrane-bound molecule that is proteolytically cleaved to generate a 53 amino acid peptide hormone that stimulates the cells. EGF or other mitogenic growth factors can be supplied to the stem cells in this manner. During the culture of stem cells, mitogenic growth factors may be added to the medium every 2 days, while the medium is preferably replaced every 4 days. Generally, the mitogenic factors are selected from the group consisting of: i) EGF, TGF-alpha, and KGF; ii) EGF, TGF-alpha, and FGF7; iii) EGF, TGF-alpha, and FGF; iv) EGF and KGF; v) EGF and FGF7; vi) EGF and FGF; vii) TGF-alpha and KGF; viii) TGF-alpha and FGF7; or ix) TGF-alpha and FGF. In certain embodiments, the present disclosure includes a stem cell culture medium comprising a Wnt surrogate molecule as disclosed herein, for example, optionally in combination with one or more growth factors or combinations thereof as described herein.

[0209] These methods of enhancing stem cell proliferation can be used to grow new organoids and tissues from stem cells, as described, for example, in WO2010 / 090513, WO2012 / 014076, Sato et al., 2011 (GASTROENTEROLOGY 2011;141:1762-1772), and Sato et al., 2009 (Nature 459,262-5).

[0210] In some embodiments, Wnt surrogate molecules are used to enhance stem cell regeneration. Exemplary target stem cells include, but are not limited to, muscle satellite cells; hematopoietic stem cells and progenitor cells derived therefrom (U.S. Patent No. 5,061,620); neural stem cells (see Morrison et al. (1999) Cell 96:737-749); embryonic stem cells; mesenchymal stem cells; mesodermal stem cells; hepatic stem cells; adipose tissue-derived stem cells, etc.

[0211] Other embodiments of the present invention relate, in part, to diagnostic applications for detecting the presence of cells or tissues expressing one or more Fzd receptors or LRP5 or LRP6 receptors. Thus, the present disclosure provides methods for detecting one or more Fzd receptors or LRP5 or LRP6 receptors in a sample, for example, for detecting cells or tissues expressing Fzd1. Such methods can be applied to a variety of known detection formats, including, but not limited to, immunohistochemistry (IHC), immunocytochemistry (ICC), in situ hybridization (ISH), whole mount in situ hybridization (WISH), fluorescent DNA in situ hybridization (FISH), flow cytometry, enzyme immunoassay (EIA), and enzyme-linked immunoassay (ELISA), for example, by detecting binding of a Wnt surrogate molecule.

[0212] ISH is a type of hybridization that uses labeled complementary DNA or RNA strands (i.e., primary binders) to localize specific DNA or RNA sequences within a portion or section of a cell or tissue (in situ), or within the entire tissue if the tissue is small enough (whole mount). Those skilled in the art will understand that this ISH is different from immunohistochemistry, which uses antibodies as primary binders to localize proteins within tissue sections. DNA ISH can be used on genomic DNA to determine the structure of chromosomes. Fluorescent DNA ISH (FISH) can be used in medical diagnostics, for example, to assess chromosomal integrity. RNA ISH (hybridization histochemistry) is used to measure and localize mRNA and other transcripts within tissue sections or whole mounts.

[0213] In various embodiments, the Wnt surrogate molecules described herein are conjugated with a detectable label that can be detected directly or indirectly. In this regard, antibody "conjugate" refers to a Wnt surrogate molecule that is covalently linked with a detectable label. In the present invention, DNA probes, RNA probes, monoclonal antibodies, their antigen-binding fragments, their antibody derivatives, such as single-chain variable fragment antibodies or epitope tagged antibodies, can all be covalently linked with a detectable label. In "direct detection", only one detectable antibody is used, i.e., a detectable primary antibody. Thus, direct detection means that the antibody that is conjugated with a detectable label can be detected by itself without the need to add a second antibody (secondary antibody).

[0214] A "detectable label" is a molecule or substance capable of producing a detectable signal (e.g., visually, electrically, or otherwise) that indicates the presence and / or concentration of the label in a sample. When conjugated to an antibody, the detectable label can be used to localize and / or quantify the target to which a specific antibody is directed. The presence and / or concentration of the target in a sample can thereby be detected by detecting the signal produced by the detectable label. The detectable label can be detected directly or indirectly, and several different detectable labels conjugated to different specific antibodies can be used to detect one or more targets.

[0215] Examples of detectable labels that can be directly detected include fluorescent dyes, radioactive substances, and metal particles. In contrast, indirect detection requires the application of one or more additional antibodies, i.e., secondary antibodies, after the application of a primary antibody. Thus, detection is performed by detecting the binding of the secondary antibody or binder to the detectable primary antibody. Examples of detectable primary binders or antibodies that require the addition of a secondary binder or antibody include detectable enzyme binders and detectable hapten binders.

[0216] In some embodiments, the detectable label is conjugated to a nucleic acid polymer that comprises a first binding agent (e.g., in an ISH, WISH, or FISH process). In other embodiments, the detectable label is conjugated to an antibody that comprises a first binding agent (e.g., in an IHC process).

[0217] Examples of detectable labels that can be conjugated to the Wnt surrogate molecules used in the methods of the present disclosure include fluorescent labels, enzyme labels, radioisotopes, chemiluminescent labels, electrochemiluminescent labels, bioluminescent labels, polymers, polymer particles, metal particles, haptens, and dyes.

[0218] Examples of fluorescent labels include 5-(and 6)-carboxyfluorescein, 5- or 6-carboxyfluorescein, 6-(fluorescein)-5-(and 6)-carboxamidohexanoic acid, fluorescein isothiocyanate, rhodamine, tetramethylrhodamine, and dyes such as Cy2, Cy3, and Cy5, optionally substituted coumarins (including AMCA), PerCP, phycobiliproteins (including R-phycoerythrin (RPE) and allophycoerythrin (APC)), Texas Red, Princeton Red, green fluorescent protein (GFP) and its analogs, and conjugates of R-phycoerythrin or allophycoerythrin, inorganic fluorescent labels, e.g., particles based on semiconductor materials such as coated CdSe nanocrystallites.

[0219] Examples of polymer particle labels include polystyrene, PMMA, or silica microparticles or latex particles into which fluorescent dyes can be embedded, or polymer micelles or capsules containing dyes, enzymes, or substrates.

[0220] Examples of metal particles include gold particles and coated gold particles, which can be converted by silver staining. Examples of haptens include DNP, fluorescein isothiocyanate (FITC), biotin, and digoxigenin. Examples of enzyme labels include horseradish peroxidase (HRP), alkaline phosphatase (ALP or AP), β-galactosidase (GAL), glucose-6-phosphate dehydrogenase, β-N-acetylglucosaminidase, β-glucuronidase, invertase, xanthine oxidase, firefly luciferase, and glucose oxidase (GO). Examples of commonly used horseradish peroxidase substrates include 3,3'-diaminobenzidine (DAB), diaminobenzidine with nickel enhancement, 3-amino-9-ethylcarbazole (AEC), benzidine dihydrochloride (BDHC), Hanker-Yates reagent (HYR), Indophane blue (IB), tetramethylbenzidine (TMB), 4-chloro-1-naphthol (CN), and alpha-naphthol. Pyronine (alpha-NP), o-dianisidine (OD), 5-bromo-4-chloro-3-indolyl phosphate (BCIP), nitro blue tetrazolium (NBT), 2-(p-iodophenyl)-3-p-nitrophenyl-5-phenyl tetrazolium chloride (INT), tetranitro blue tetrazolium (TNBT), 5-bromo-4-chloro-3-indoxyl-beta-D-galactoside / ferricyanide(II) (BCIG / FF).

[0221] Examples of commonly used horseradish peroxidase substrates and alkaline phosphatase substrates include naphthol-AS-B1-phosphate / Fast Red TR (NABP / FR), naphthol-AS-MX-phosphate / Fast Red TR (NAMP / FR), naphthol-AS-B1-phosphate / Fast Red TR (NABP / FR), naphthol-AS-MX-phosphate / Fast Red TR (NAMP / FR), naphthol-AS-B1-phosphate / New Fuchsin (NABP / NF), bromochloroindolyl phosphate / nitro blue tetrazolium (BCIP / NBT), 5-bromo-4-chloro-3-indolyl-bd-galactopyranoside (BCIG).

[0222] Examples of luminescent labels include luminol, isoluminol, acridinium esters, 1,2-dioxetanes, and pyridopyridazines. Examples of electrochemiluminescent labels include ruthenium derivatives. Examples of radioactive labels include radioisotopes of iodide, cobalt, selenium, tritium, carbon, sulfur, and phosphorus.

[0223] The detectable label may be conjugated to an antibody as described herein, or to any other molecule (e.g., an antibody, a nucleic acid probe, or a polymer) that specifically binds to the biological marker of interest. In addition, one skilled in the art will understand that the detectable label may be conjugated to a second, and / or a third, and / or a fourth, and / or a fifth binding agent or antibody, etc. In addition, one skilled in the art will understand that each additional binding agent or antibody used to characterize the biological marker of interest serves as a signal amplification step. The biological marker may be visually detected, for example, using a light microscope, a fluorescent microscope, or an electron microscope, when the detectable label is, for example, a dye, a colloidal gold particle, or a luminescent reagent. A visually detectable substance bound to the biological marker may also be detected using a spectrophotometer. When the detectable substance is a radioisotope, detection may be visually by autoradiography or non-visually using a scintillation counter. See, for example, Larsson, 1988, Immunocytochemistry: Theory. and Practice, (CRC Press, Boca Raton, Fla.); Methods in Molecular Biology, vol. 80 1998, John D. Pound (ed.) (Humana Press, Totowa, NJ).

[0224] The invention further provides kits for detecting one or more Fzd or LRP5 / 6 receptors or cells or tissues expressing one or more Fzd or LRP5 / 6 receptors in a sample, comprising at least one antibody, polypeptide, polynucleotide, vector, or host cell described herein. In certain embodiments, the kits can include buffers, enzymes, labels, substrates, beads or other surfaces to which the antibodies of the invention are attached, and the like, and instructions for use.

[0225] All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent publications referenced herein and / or listed in the Application Data Sheet are hereby incorporated by reference in their entirety.

[0226] From the foregoing it will be appreciated that, although specific embodiments of the invention have been described for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. EXAMPLES

[0227] Example 1 Exemplary Wnt Surrogate Molecule Formats Wnt surrogates having a variety of different formats as disclosed herein were generated, including the exemplary formats shown below, each of which contained a binding domain that binds to one or more Fzd receptors ("binding agents") and a binding domain that binds to the LRP5 and / or LRP6 receptors ("binding agents").

[0228] As shown in FIG. 1A, when the binder for one receptor is a Fab and the binder for the other receptor is a Nab or scFv, these can be organized into several different configurations. In some cases, the Fab binder can first be reformatted into an all-IgG format, and then the Nab binder can be fused to any of the four available termini of the IgG. For example, fusion of the Nab can be made to the N-terminus of the IgG light chain (LC, the fusion is designated NL and shown at the top left), to the N-terminus of the IgG heavy chain (HC, the fusion is designated NH and shown at the top right), to the C-terminus of the LC (the fusion is designated CL and shown at the center right), and to the C-terminus of the HC (the fusion is designated CH and shown at the middle left). The linker between the IgG and the Nab and the length of the linker can vary. These four formats are bispecific and bivalent, being bivalent binders for each of the receptors. An alternative way to bring the two binders together is a hetero-Ig format (shown in the lower center) where the Fab binder is presented as a half antibody and the Nab is fused to the N-terminus of the Fc. The two halves can be brought together by mutations in the CH3 domain (e.g., knobs-into-holes) that favor the formation of heterodimers. The linker between the Nab binder and the Fc and its length can be varied. This format is bispecific but monovalent for each receptor. Any of the formats described in this example can also be replaced with scFv fragment binders.

[0229] As shown in FIG. 1B, when the binder for one receptor is a Fab and the binder for the other receptor is also a Fab, they can be organized into several different configurations. In one approach, one Fab binder is first reformatted into an all-IgG format (shown at the top). The second Fab binder may be fused to the N-terminus of an IgG. The two HCs may be fused together with a linker in between. The LC may be fused or unfused. The linker and its length may vary. This format is a bispecific and bivalent format. Alternatively, the second Fab binder LC may be fused to the HC of an IgG with a linker of various lengths in between. The second Fab binder HC may be fused or unfused to the LC of an IgG. A variation of this format is called tandem Fab IgG (or FIT-Ig). In another approach, two binders can be packaged together as a hetero-Ig by mutations in the CH3 domain that favor the assembly of a heterodimer, with each of the two arms binding to one receptor (shown at the bottom). This format is a bispecific and monovalent binder.

[0230] As shown in FIG. 1C, when the binder for one receptor is a Nab and the binder for the other receptor is also a Nab, they can be assembled in several different configurations. In a bispecific and bivalent format, in certain cases, two Nab binders can be fused in tandem (shown in the top row) or fused to two different ends of Fc (shown in the middle row). The linker and its length between Nab and Nab or Nab and Fc can be varied. Alternatively, two Nabs can be assembled together as a hetero-Ig to generate a bispecific and monovalent format (shown in the bottom row). As in FIG. 1A, the Nab domain here can also be replaced by the scFv domain of the binder. In all examples, Nab and scFv can also be mixed in certain combinations.

[0231] As shown in Figure ID, binding agents for Fzd and LRP may be linked together in a diabody (or DART) configuration. The diabody may also be in a single chain configuration. If the diabody is fused to Fc, this creates a bivalent bispecific format. Without the fusion to Fc, this is a monovalent bispecific format.

[0232] A number of Wnt surrogates were generated that correspond to different configurations. Such surrogates include those listed in Table 3. Such exemplary Wnt surrogates include one, two, or three polypeptides, the sequences of which are shown as SEQ ID NO:1, SEQ ID NO:2, and / or SEQ ID NO:3. The sequences can include a leader peptide sequence, a Nab sequence, a linker, and / or a heavy or light chain sequence. Annotated sequences are shown in FIG. 19. The leader peptide sequence is shown in italics, the linker sequence is shown in underline, the Nab sequence is shown in bold, and the remaining sequence is the heavy or light chain sequence. The Fzd binder ID and LRP binder ID correspond to the clone numbers shown in Tables 1A-B and 2A-B for various Fzd-binding or LRP5 / 6-binding antibodies or antigen-binding fragments thereof.

[0233] The Wnt surrogates beginning with "R2M3" contain a different LRP6 binding domain fused to the N-terminus of the light chain region of the anti-Fzd antibody or antigen-binding fragment thereof designated 001S-A04. The first six Wnt surrogates beginning with "18R5" in Table 3 contain a different LRP6 binding domain fused to the N-terminus of the anti-Fzd antibody or antigen-binding fragment thereof designated 18R5. The Wnt surrogates beginning with "1R" contain an anti-LRP6 antibody or antigen-binding fragment thereof designated "009S-E04" fused to the N-terminus of a different anti-Fzd antibody or antigen-binding fragment thereof. In the case of "R2M3-26CH", the LRP6 binding region is fused to the C-terminus of the Fzd binding region. In the case of "R2M3-26NH", the LRP6 binding region is fused to the N-terminus of the Fzd binding region. In the case of "R2M3-26CL", the LRP6 binding region is fused to the C-terminus of the Fzd binding region. In the case of "R2M3-26NL", the LRP6 binding region is fused to the N-terminus of the Fzd binding region. In the case of "R2M3-26Fab" and "R2M3-32Fab", the LRP6 binding region is fused to the N-terminus of the Fzd binding region. In the case of "hetero-Ig", the LRP6 binding region is fused to the N-terminus of the human Fc_hole and pairs with the light and heavy chain human IgG1_knobs of the Fzd binder. The Wnt surrogates beginning with "17SB9" contain a different LRP6 binding domain fused to the N-terminus of the light chain region of the anti-Fzd antibody, or antigen-binding fragment thereof, designated 017S-B09. The Wnt surrogates beginning with "1R-C07" contain a different LRP6 binding domain fused to the N-terminus of the light chain region of the anti-Fzd antibody, or antigen-binding fragment thereof, designated 001S-B03. The Wnt surrogates beginning with "R2M13" contain a different LRP6 binding domain fused to the N-terminus of the light chain region of the anti-Fzd antibody, or antigen-binding fragment thereof, designated 004S-G06. The Wnt surrogates beginning with "3SD10" contain a different LRP6 binding domain fused to the N-terminus of the light chain region of the anti-Fzd antibody, or antigen-binding fragment thereof, designated 003S-D10.The Wnt surrogates beginning with "4SD1" contain a different LRP6 binding domain fused to the N-terminus of the light chain region of the anti-Fzd antibody or antigen-binding fragment thereof designated 004S-D01. The Wnt surrogates beginning with "14SB6" contain a different LRP6 binding domain fused to the N-terminus of the light chain region of the anti-Fzd antibody or antigen-binding fragment thereof designated 014S-B06. [Table 3-1] [Table 3-2] [Table 3-3] [Table 3-4] [Table 3-5]

[0234] Example 2 Characterization of the Wnt surrogate molecule R2M3-26 The R2M3-26 molecule consists of an Fzd binder (R2M3) and an LRP6 binder (26). As shown in Figure 2A, the LRP6 binder 26 was fused to the N-terminus of the R2M3 LC using a 5 amino acid linker. R2M3 was in the form of an IgG. The protein was purified by a protein A affinity column followed by a size exclusion chromatography (SEC) step. The absorbance trace from SEC and an SDS-PAGE gel of the SEC fractions are shown in Figure 2B. The canonical Wnt signaling activation ability of R2M3-26 was tested in a Wnt-responsive 293 reporter cell line (293STF). The 293STF reporter activity trace across the SEC fractions is shown in Figure 2B. The reporter activity peak correlated with the protein peak. The peak fractions were further characterized by dose response of 293STF cells in the absence and presence of R-spondin (Figure 2D). R2M3-26 induced reporter activity in a dose-dependent manner, and it was enhanced by the presence of R-spondin, similar to the natural Wnt ligand, whereas R2M3 IgG alone without the attachment of LRP-binding arms did not induce reporter activity. The interaction ability of R2M3-26 with its target Fzd1 ECD was performed by Octet interaction assay (Fig. 2C), and the results showed that the fusion of LRP6-binding arm 26 did not affect the interaction of R2M3 with its target Fzd.

[0235] Example 3 Characterization of the Wnt surrogate molecule R2M3-32 The R2M3-32 molecule consists of an Fzd binder (R2M3) and an LRP6 binder (32). As shown in Figure 3A, the LRP6 binder 32 was fused to the N-terminus of the R2M3 LC using a 5 amino acid linker. R2M3 was in the form of an IgG. The protein was purified by a protein A affinity column followed by a size exclusion chromatography (SEC) step. The absorbance trace from SEC and an SDS-PAGE gel of the SEC fractions are shown in Figure 3B. The canonical Wnt signaling activation ability of R2M3-32 was tested in a Wnt-responsive 293 reporter cell line (293STF). The 293STF reporter activity trace across the SEC fractions is shown in Figure 3B. The reporter activity peak correlated with the protein peak. The peak fractions were further characterized by dose response of 293STF cells in the absence and presence of R-spondin (Figure 3D). R2M3-32 induced reporter activity in a dose-dependent manner, which was enhanced by the presence of R-spondin. Meanwhile, R2M3 IgG alone without the attachment of LRP-binding arms did not induce reporter activity. The interaction ability of R2M3-32 with its target Fzd1 extracellular domain (ECD) was performed in an Octet interaction assay (Figure 3C). The results showed that the fusion of LRP6-binding arm 32 did not affect the interaction of R2M3 with its target Fzd.

[0236] Example 4 The activity of R2M3-26 and R2M3-32 can be inhibited by soluble Fzd ECD and by R2M3 IgG alone without the LRP-binding arm The 293STF reporter assay was used to quantify the ability of soluble Fzd extracellular domain (ECD) or R2M3 IgG alone to inhibit Wnt surrogates. Fzd1ECD-Fc or R2M3 IgG was titrated in the 293STF reporter assay with fixed concentrations of R2M3-26 or R2M3-32. Both Fzd1ECD-Fc and R2M3 IgG dose-dependently inhibited reporter signaling induced by R2M3 IgG (Figure 4A) and R2M3-32 (Figure 4B), whereas the negative control molecule Fc alone had no effect.

[0237] Example 5 Characterization of R2M3-LRP6 binder fusions in 293, Huh7, A375, and BNL.CL2 Wnt-dependent reporter assays The Fzd binder R2M3 was fused to additional LRP6 binders 23, 25, 26, 27, 28, 29, 31, 32, 33, and 36. The LRP6 binders were Nabs fused to the N-terminus of R2M3 LC using a 5 amino acid linker. The proteins were purified by protein A affinity column followed by a SEC step. The fusion proteins were tested in Wnt-dependent reporter assays in 293, Huh7, A375, and BNL.CL2 cell lines, where they activated Wnt signaling to various levels. R2M3 was also fused to two non-LRP6 binder Nabs (24 and 34) in the same format as the Lrp6 binders. These two non-binders showed no activity in the Wnt-dependent 293 reporter assay (Figure 5). This suggests that the Wnt activity observed in fusions of R2M3 with 23, 25, 26, 27, 28, 29, 31, 32, 33, and 36 is dependent on the presence of both Fzd and Lrp, which mimics the function of the natural ligands.

[0238] Example 6 Characterization of 18R5-LRP6 binder fusions in 293, A375, and BNL.CL2 Wnt-dependent reporter assays The Fzd binder 18R5 was fused to the LRP6 binders 26, 28, 31, 32. The LRP6 binders were made into Nabs and fused to the N-terminus of 18R5 LC using a 5 amino acid linker. The proteins were purified by a Protein A affinity column followed by a SEC step. The fusion proteins were tested in Wnt-dependent reporter assays in 293, A375, and BNL.CL2 cell lines and showed the ability to activate Wnt signaling (Figure 6).

[0239] Example 7 Characterization of 18R5-LRP5 binder fusions in Wnt-dependent reporter assays Fzd binder 18R5 was fused to LRP5 binders 5, 7, 8, and 9. LRP5 binders were fused to the N-terminus of 18R5 LC using a 5 amino acid linker as Nab. These proteins were purified by Protein A affinity column followed by a SEC step. The fusion proteins were tested in a Wnt-dependent reporter assay in 293 cell line and were able to activate Wnt signaling (Figure 7).

[0240] Example 8 Characterization of various Fzd-binder-LRP6-binder 26 fusions in Wnt-dependent reporter assays Various Fzd binders 1R-B05, 1R-C01, 1R-C07, 1R-E01, 1R-E06, 1R-G05, 1R-G06, 1R-H04 in IgG format were fused to LRP6 binder 26. LRP6 binder Nab was fused to the N-terminus of various Fzd binders LC using a 5 amino acid linker. These proteins were purified by protein A affinity column followed by a SEC step. SDS-PAGE gel analysis of the SEC peak fractions is shown in Figure 8A. The fusion proteins were tested in a Wnt-dependent reporter assay in 293 cell line in the presence of Rspo and they were able to activate Wnt signaling (Figure 8B).

[0241] Example 9 SAR analysis of IgG-Nab fusion format SAR analysis of IgG-Nab fusions was performed by rotating the attachment position of Nab to different termini of IgG HC or LC as illustrated in FIG. 1A. CH indicates Nab attachment to the C-terminus of the heavy chain, NH indicates Nab attachment to the N-terminus of the heavy chain, CL indicates Nab attachment to the C-terminus of the light chain, and NL indicates Nab attachment to the N-terminus of the light chain. SAR of three pairs of IgG-Nab fusions was shown. These are the pairs between R2M3 and 26, R2M3 and 32, and 18R5 and 26. Assays were performed on Wnt-responsive 293 reporter cells in the presence of Rspo, and Wnt signaling was activated to various levels (FIG. 9). These results demonstrate that the attachment position of the fusion and the geometric arrangement between the binding domains of Fzd and LRP play a role in the Wnt signaling activation ability of Wnt surrogate molecules.

[0242] Example 10 Characterization of R2M3-26 in Fab format The molecule R2M3-26 Fab consists of an Fzd binder (R2M3) and an LRP6 binder (26). As shown in FIG. 10A, the LRP6 binder 26 was fused to the N-terminus of R2M3 LC using a 5 amino acid linker. R2M3 was in the form of a Fab. The protein was purified by Ni-NTA affinity column followed by a size exclusion chromatography (SEC) step. The absorbance trace from SEC and an SDS-PAGE gel of the SEC fractions are shown in FIG. 10B. The canonical Wnt signaling activation ability of R2M3-26 in the Fab format was tested in Wnt-responsive 293 reporter cells (293STF). The 293STF reporter activity trace in the SEC fractions is shown in FIG. 10B. Unlike when R2M3 was in the IgG format as shown in FIG. 2, the reporter activity peak from R2M3 in the Fab format did not correlate with the protein peak. These results suggest that the R2M3-26 fusion in Fab format does not efficiently induce canonical Wnt signaling as detected by reporter assays.

[0243] Example 11 Characterization of R2M3-32 in Fab format The molecule R2M3-32 Fab consists of an Fzd binder (R2M3) and an LRP6 binder (32). As shown in FIG. 11A, the Lrp6 binder 32 was fused to the N-terminus of R2M3 LC using a 5 amino acid linker. R2M3 was in the form of a Fab. The protein was purified by Ni-NTA affinity column followed by a size exclusion chromatography (SEC) step. The absorbance trace from SEC and an SDS-PAGE gel of the SEC fractions are shown in FIG. 11B. The canonical Wnt signaling activation ability of R2M3-32 in the Fab format was tested in Wnt-responsive 293 reporter cells (293STF). The 293STF reporter activity trace in the SEC fractions is shown in FIG. 11B. Unlike when R2M3 was in the IgG format as shown in FIG. 3, the reporter activity peak from R2M3 in the Fab format did not correlate with the protein peak. These results suggest that the R2M3-32 fusion in Fab format does not efficiently induce canonical Wnt signaling as detected by reporter assays.

[0244] Example 12 Characterization of the heterologous Ig format R2M3-26 The molecule R2M3-26 heteroIg consists of an Fzd binder (R2M3) and an LRP6 binder (26), as illustrated in FIG. 12A and described in FIG. 1A. The protein was purified by a Protein A affinity column followed by a size exclusion chromatography (SEC) step. The peak fractions from the SEC column were tested for dose response in Wnt-responsive 293STF reporter cells in the absence or presence of R-spondin (FIG. 12B). Compared to the IgG format of R2M3-26 (described in FIG. 2), R2M3-26 heteroIg did not effectively induce canonical Wnt signaling as detected by the 293 reporter assay.

[0245] Example 13 Characterization of 26-17SB9 in Nab-Nab format The molecule 26-17SB9 Nab-Fc-Nab is composed of an LRP6 binder (26) and an Fzd binder (17SB9) as illustrated in FIG. 13A and described in FIG. 1C. The protein was purified by a Protein A affinity column followed by a size exclusion chromatography (SEC) step. The peak fractions from the SEC column were tested for dose response in Wnt-responsive 293STF reporter cells in the absence or presence of R-spondin (FIG. 13B). 26-17SB9 in the Nab-Fc-Nab format induced canonical Wnt signaling as detected in the 293 reporter assay.

[0246] Further combinations of 26 and 17SB9 were also constructed (Figure 13C) and tested in the 293 reporter assay. As shown in Figures 13D and 13E, these various combinations of 26 and 17SB9 arranged in different tandem formats or on different ends of the Fc fragment all activated Wnt signaling to different levels in the presence of 20 nM R-spondin.

[0247] Example 14 Characterization of 18R5-LRP5 binder fusions in tandem scFv format The Fzd binder 18R5, the LRP6E1E2 binder 1115.3 (described in PCT Publication No. WO2009 / 064944), and the LRP6E3E4 binder YW211.31.57 (described in PCT Publication No. WO2011 / 119661) were converted to scFv format. The 1115.3_scFv or YW211.31.57_scFv are assembled to the N-terminus of the 18R5_scFv using a 5, 10, or 15 amino acid linker, and the 18R5_scFv C-terminus is fused to the human Fc domain. In another set of examples, 1115.3_scFv or YW211.31.57_scFv are assembled to the C-terminus of 18R5 scFv using 5, 10, or 15 amino acid linkers, and the human Fc domain is fused to the C-terminus of the LRP binder. These formats are illustrated in the left panel of Figure 14G. In another example, 18R5_scFv and the LRP binder, 1115.3_scFv, or the LRP binder, YW211.31.57_scFv, were fused to the two ends of a human Fc domain (illustrated in the right panel of Figure 14G). These proteins were purified by Protein A affinity column followed by a SEC step.

[0248] The fusion proteins were tested in Wnt-dependent reporter assays in 293 cells. 18R5_scFv-1115.3_sdFv-Fc and 1115.3_scFv-18R5_scFv-Fc with 5, 10, or 15-mer linkers were able to activate Wnt signaling (Figures 14A and 14B). 18R5_scFv-YW211.31.57_scFv-Fc and YW211.31.57_scFv-18R5_scFv-Fc with different linkers activated Wnt signaling (Figures 14C and 14D). In addition, 18R5_scFv and 1115.3_scFv or YW211.31.57 fused with the two ends of Fc also activated Wnt signaling (Figures 14E and F). All of these scFv formats activated Wnt signaling, although potency and overall maximal efficacy may vary depending on the binder combination, linker length, and relative orientation.

[0249] In another example, 1115.3_scFv or YW211.31.57_scFv was assembled to the N-terminus or C-terminus of 18R5_scFv using 5, 10, or 15 amino acid linkers without additional Fc fusion to create bispecific but monovalent binding to Fzd or LRP, respectively. As shown in Figure 14H, 1115.3_scFv and 18R5_scFv fusions did not effectively activate Wnt signaling in the presence of 20 nM R-spondin in 293 reporter cells.

[0250] Example 15 Generation of Wnt surrogate molecules in Fab-IgG format Wnt mimetic or surrogate molecules can be produced in various formats where both FZD and LRP binding agents are Fabs. Various approaches such as charge pairing, "knobs in holes", heavy and light chain crossover in Fabs can be used to ensure proper heavy and light chain pairing. Two examples are shown below.

[0251] 1. Charge pairing (cp) approach to Fab-on-IgG format: The heavy chain (VH-CH1) domain of anti-LRP6 Fab was fused in tandem with the N-terminus of the heavy chain (VH-CH1-CH2-CH3) of anti-FZD binders by a 5-, 10-, or 15-mer amino acid linker. The VH-CH1 domains of both anti-LRP6 and anti-FZD each contain three amino acid mutations for pairing with their own partner light chain (Q39D, Q105D, S183K for anti-LRP6 Fab, Q39K, Q105K, S183E for anti-FZD Fab), and the partner light chain also contains three complementary amino acid mutations (Q38K, A / S43K, S176E for anti-LRP6 light chain, Q38D, A / S43D, S176K for anti-FZD light chain). The order of anti-LRP6 and anti-FZD Fab may be reversed, where the anti-FZD binder is a Fab and is fused to the anti-LRP binder in IgG format (FIG. 15A).

[0252] 2. HC-LC crossover approach to Fab-on-IgG format: The light chain (VL-CL) domain of the anti-LRP6 binder was fused in tandem to the N-terminus of the heavy chain (VH-CH1-CH2-CH3) of the anti-FZD binder by a 5-, 10-, or 15-mer amino acid linker. The second construct was the VH-CH1 of the anti-LRP6 binder, and the third construct was the VL-CL of the anti-FZD binder. As in the previous example, the order of the anti-LRP6 and anti-FZD binders may be reversed, in which case the anti-FZD binder Fab is fused to the N-terminus of the anti-LRP binder in IgG format (Figure 15A).

[0253] Several different pairs of LRP and FZD binders were assembled in these formats and tested in the Wnt-responsive 293 reporter cell line (293STF). As an example, anti-LRP6E1E2 binder 421.1 (described in PCT Publication No. WO2009 / 064944) was fused to the N-terminus of anti-FZD binder R2M3 using a charge pairing approach to generate 421.1-R2M3 cp. 421.1-R2M3 cp dose-dependently activated Wnt signaling in the 293 reporter assay (Figure 15B). Anti-FZD binder 1RC07 was fused to the N-terminus of anti-LRP binder 10SA7 using 5, 10, or 15-mer linkers. All three fusion proteins activated Wnt signaling (Figure 15C). Further fusions of the anti-FZD binder 1RC07 to the anti-LRP binder 10SG7 were performed in the reversed order, with 10SG7 in IgG format fused to 1RC07 in Fab format, or 10SG7 as Fab fused to the N-terminus of 1RC07 as IgG, using 5-, 10-, or 15-mer amino acid linkers. All fusion molecules activated Wnt signaling, although some preferences in orientation and linker length were observed (Figures 15D and 15E).

[0254] The HC-LC crossover Fab-IgG format was also tested. The anti-FZD binder 1RC07 LC was fused to the N-terminus of the anti-LRP6 binder 10SA7 HC to generate 1RC07-5:10SA7 L→H. The LC of the anti-LRP6E1E2 binder 1115.3 (described in PCT Publication No. WO2009 / 064944) was fused to the N-terminus of the anti-FZD binder R2M3 HC using a 5- or 10-mer linker to generate 1115.3:5:R2M3 L→H or 1115.3:10:R2M3 L→H, respectively. These molecules also activated Wnt signaling (Figures 15F and 15G).

[0255] Example 16 Characterization of R2M3-26 in F(ab')2 format R2M3-26 IgG1 was digested with IDES (Promega, WI) for 2 hours at 37°C. The majority of the digestion products were R2M3-26F(ab')2 (Figure 16A), some partial digestion products with one Fab still attached to the Fc (herein referred to as R2M3-26F(ab')2-Fc) were also detected, and uncleaved R2M3-26 was not detected. The cleavage products were purified by anti-lambda resin to remove the Fc fragment, and then SEC polishing was performed afterwards to separate R2M3-26F(ab')2 from R2M3-26F(ab')2-Fc. An SDS-PAGE gel of the final purified protein is shown in Figure 16B. R2M3-26F(ab')2 activity was measured by STF assay in HEK293 cells. R2M3-26F(ab')2 was able to activate Wnt signaling (Figure 16C).

[0256] Example 17 Further characterization of Wnt surrogate molecules FZD-binding agents were fused to LRP-binding agents. In this example, LRP5 or 6-binding agents were fused to the N-terminus of FZD-binding agent LC as Nabs (or VHHs) using a 5 amino acid linker (as shown in Figure 17A). These proteins were purified by Protein A affinity column followed by a SEC step. The purified proteins were tested in Wnt-dependent reporter assays in 293 cells (Figure 17B, C, D, H) or 293 cells co-transfected with FZD4 expression constructs (Figure 17E, F) or 293 cells co-transfected with FZD9 expression constructs (Figure 17G) in the presence of 20 nM R-spondin. These molecules activated Wnt signaling with different levels of potency and efficacy.

[0257] Example 18 Characterization of 10SG11-1RC07 in 2Fv-Ig format The molecule 10SG11-1RC07 consists of an N-terminal LRP binder (10SG11) and an Fzd binder (1RC07). The Fv of 10SG11 was fused to the N-terminus of 1RC07 using a 5 amino acid linker as shown in Figure 18A. 1RC07 took the form of an IgG1 with Fc mutations L234A / L235A / P329G. The protein was purified by a Protein A affinity column followed by a SEC step. The fusion protein was tested in a Wnt-dependent reporter assay in 293 cell line and showed the ability to activate Wnt signaling (Figure 18B-C).

[0258] Example 19 In vivo PK / PD characterization of R2M3-26 Six-week-old C57Bl / 6J mice were obtained from Jackson Laboratories (Bar Harbor, ME, USA) and housed three per cage. All animal experiments followed the standards of the Guide for the Care and Use of Laboratory Animals prepared by the National Academy of Sciences. Animal experimental protocols were approved by the Surrozen Institutional Animal Care and Use Committee. Mice were allowed to acclimate for a minimum of 2 days before the start of the experiment. Mice had unlimited access to purified, laboratory-grade acidified water and were fed ad libitum (2018 Teklad global 18% protein rodent diet). Mice were housed in a 30%-70% humidity environment and at room temperatures ranging from 20°C to 26°C on a 12 / 12-h light / dark cycle.

[0259] For pharmacokinetic (PK) studies (Figure 20A), n=3 per group was used. Mice were administered 1 mg / kg (10 ml / kg in saline) of R2M3-26 (with effectorless fc mutation) using intravenous (IV) or intraperitoneal (ip) injection. Mice were anesthetized with isoflurane and blood was removed from the retro-orbital plexus, tail vein, or heart at 10 min, 30 min, 1, 4, 24, 72, or 144 h after injection. Blood was allowed to clot at room temperature and then centrifuged at 8,000 g for 7 min. Serum was removed and stored at -20°C until serum R2M3-26 concentrations were measured by ELISA using anti-human IgG Fc fragment (Jackson Immuno Research Labs NC9747692).

[0260] For pharmacodynamics (PD) studies (Figure 20B), n=6 per group were used. Mice were injected ip with the indicated doses (10ml / kg in saline). Control mice received saline only. After 8 hours, mice were anesthetized with isoflurane and blood was collected by cardiac puncture. Blood was allowed to clot at room temperature and then centrifuged at 10,000g for 7 minutes. Serum was removed and stored at -20°C until serum R2M3-26 concentrations were measured by ELISA. Portions of the left liver lobe were snap frozen in liquid nitrogen and stored at -80°C for RNA analysis. MagMAX™ mirVana™ Total RNA Isolation RNA was extracted from liver samples using the High Capacity cDNA Reverse Transcription Kit (ThermoFisher, 43-688-14). cDNA was generated using TaqMan Fast Advanced Master Mix (ThermoFisher, 4444963) and Mm00443610_m1 Axin2. Axin2 mRNA expression was measured using Probe (Thermofisher, 4331182).

[0261] These studies demonstrated that R2M3-26 was stable, highly bioavailable and active in vivo, as demonstrated by induction of Axin2 mRNA expression.

[0262] Example 20 In vivo bone model and characterization of AAV-delivered Wnt surrogates In vivo experiments were performed by infecting mice with an AAV vector expressing Flag- and His-tagged 18R5-DKK1c protein (AAV-18R5-DKK1c-FlagHis). 18R5-DKK1c is a fusion protein containing the frizzled binding antibody 18R5 in scFv format fused to DKK1c (described in PCT Publication No. WO2016 / 040895 (e.g., FIG. 5)). Control mice were treated with vehicle alone, romosozumab, an AAV vector expressing green fluorescent protein (GFP) (AAV-CAG-GFP), or an AAV vector expressing a fusion protein containing an anti-GFP scFV fused to mutant DKK1c (AAV-ScFv(anti-GFP)-DKK1cF234K-Flag-His). Animals were sacrificed 28 days after infection and bone mineral density, bone volume, and other characteristics were measured. As shown in Figures 21A-21E, systemic expression of 18R5-DKK1c resulted in a significant increase in bone mineral density as early as 14 days after systemic expression of 18R5-DKK1c, as quantified by dual energy x-ray absorptiometry (DEXA) scans. Systemic expression of 18R5-DKK1c increased bone mineral density (BMD) as measured by DEXA scans (Figure 21A) and increased serum levels of the P1NP bone formation marker (Figure 21C) in naive mice. Serum levels of AAV-ScFv(anti-GFP)-DKK1cF234K and 18R5-DKK1c were detected in serum and found to be well above the EC50 quantified in vitro (Figure 21B). AAV-CAG-GFP and AAV-ScFv(anti-GFP)-DKK1cF234K served as negative controls. Romosozumab served as a positive control, and vehicle alone served as a negative control. As shown in Figures 20D and 20E, 18R5-DKK1c also increases lumbar and total body bone mineral density (* indicates P value < 0.05, ** indicates P value < 0.0001). As shown in Figures 22A-22D, after 28 days of treatment in naive mice, AAV-mediated 18R5-DKK1c expression also increased cortical thickness of the tibia and femur as well as the femoral midshaft as measured by microCT (**** indicates P value < 0.0001).

[0263] As shown in Figures 23A and 23B, systemic expression of 18R5-DKK1c resulted in a significant increase in mineral apposition rate from baseline to single label over the final 8 days.

[0264] As shown in Figures 24A-24D, systemic expression of 18R5-DKK1c also led to an increase in osteoblast numbers and a decrease in osteoclast numbers.

[0265] As shown in Figures 25A-25C, 18R5-DKK1c treatment increased bone stiffness and ultimate load to fracture in biomechanical tests, suggesting improved resistance to fracture.

[0266] These studies demonstrated that systemic expression of 18R5-DKK1c using AAV increased bone mineral density (BMD) as measured by DEXA, and also showed that 18R5-DKK1c increased bone volume as measured by micro-CT as early as 14 days after treatment. 18R5-DKK1c also increased cortical thickness after 28 days of treatment. Systemic expression of 18R5-DKK1c resulted in a significant increase in mineral apposition rate, increased osteoblast numbers, and decreased osteoclast numbers. It also increased bone stiffness and ultimate load to fracture, suggesting improved resistance to fracture.

[0267] Example 21 In vivo bone model and characterization of Wnt surrogates produced as recombinant proteins In vivo experiments were performed by treating mice with various doses of recombinantly produced R2M3-26 protein via ip injection. Control mice were treated with vehicle only (negative control), romosozumab (positive control), anti-beta galactosidase (negative control), or IgG2-anti-GFP (negative control). Bone mineral density (BMC) measured by DEXA and bone volume measured by micro-CT were monitored longitudinally at the indicated time points. After 4 weeks of treatment, animals were sacrificed and bone characteristics were measured. Experimental data were monitored for a single injection of R2M3-26, and data from 2 weeks after treatment are shown.

[0268] As shown in Figures 26A-26D, treatment with recombinant R2M3-26 induced a rapid and sustained increase in bone mineral density (BMD) and bone volume in naive mice. Both bone volume and BMD increased rapidly, suggesting resistance to fracture.

[0269] The ovariectomy-induced osteoporosis model is a well-established high-hurdle model to determine the ability to overcome bone loss associated with hormone ablation in anabolic therapy (Zhou, S. et. al., Journal of Cellular Biochemistry, PMID:11455579). As shown in Figures 27A-27C, treatment with recombinant R2M3-26 treatment reversed bone loss in the ovariectomy-induced osteoporosis mouse model. Increased cortical thickness was observed in the trabecular bone, suggesting increased compressive strength. As shown in Figure 27D, R2M3-26 treatment increased femoral midshaft cortical thickness after 42 days as measured by micro-CT. BMD was also increased by R2M3-26 as measured by DEXA (shown in Figure 27E).

[0270] As shown in Figures 28A-28C, a single injection of R2M3-26 is sufficient to induce rapid bone formation and bone volume within one week (* indicates P value < 0.05).

[0271] As shown in Figures 29A-29D, high-dose treatment with R2M3-26 and 1R-C07-26 rapidly and significantly increased bone volume and bone mineral density, and improved bone biomechanical strength (ultimate load to failure and stiffness). 1R-C07-26 showed a robust and significant effect on bone augmentation, which persisted for 28 days. Both R2M3-26 and 1R-C07-26 significantly increased resistance to fracture by biomechanical testing after 28 days of treatment.

[0272] As shown in Figures 30A-E, high dose treatment with R2M3-26 and 1R-C07-3 rapidly and significantly increased bone volume, bone mineral density, and cortical thickness after only 14 days of treatment. 10 mpk 1R-C07-3 appeared to be more effective at increasing bone mass than any other treatment tested in this preclinical model.

[0273] These studies demonstrate that recombinant protein treatment can induce rapid and sustained increases in bone mineral density and bone volume in naive mice and in a mouse osteoporosis model. Both bone volume and bone mineral density (BMD) were rapidly increased, suggesting resistance to fracture. IgG2-anti-GFP served as a negative control. Anti-beta-galactosidase (anti-bgal) served as a negative control.

[0274] Further experiments were performed to determine the systemic skeletal effects of Wnt surrogate molecules in an ovariectomy-induced model of osteoporosis. C57BL / 6 females (n=8 / group) aged 4 weeks at the time of ovariectomy were compared to sham-operated and age-matched naïve mice. Seven months after surgery, animals were injected ip with recombinant Wnt surrogate molecules to determine the time of onset of osteoporosis. Experimental groups included R2M3-26, 1RC07-3, anti-Bgal (antibody control), and vehicle (PBS). For comparison, a separate cohort of mice received subcutaneous injections of romosozumab. Animals were treated twice weekly and followed for 4 weeks.

[0275] Total body bone mineral density (BMD) was measured weekly using dual energy x-ray absorptiometry (DEXA), as shown in Figure 31. Treatment with Wnt surrogate molecules not only restored total BMD, but could also exceed that seen in naive or non-operated animals. Four weeks after treatment, animals were assessed for vertebral resistance to compression fracture.

[0276] As shown by fracture analysis (Figure 32), treatment with Wnt surrogate molecules significantly increased the resistance of vertebrae to compression fracture, with 1RC07-3 most robustly increasing the maximum force required to fracture the vertebrae.

[0277] The Einhorn fracture model (Bonnarens F, Einhorn TA. J Orthop Res. 1984;2(1):97-101. PMID: 6491805) and delayed treatment with Wnt surrogate molecules were used to determine the ability of this therapy to induce fracture healing. Delayed treatment with 1RCO7-3 or R2M3-26 was tested to determine whether either molecule could contribute to increased fracture healing after mid-traverse fracture of the femur. C57BL / 6 females (n=8 / group) aged 16 weeks at the time of fracture were used. All animals were confirmed for the presence of a chondral callus 2 weeks after fracture before treatment was started. A delayed treatment allowing callus formation was used to elicit a pure osteogenic signal with rapid mineralization of the already existing callus.

[0278] Animals were injected ip with recombinant Wnt surrogate molecules in the following experimental groups: R2M3-26, 1RCO7-3, anti-Bgal (antibody control), and vehicle (PBS). For comparison, another cohort of mice received subcutaneous injections of romosozumab. Animals were treated twice weekly and followed for 6 weeks. Radiography was used to visualize changes in callus mineralization throughout the experiment (Figure 33A and B). Mineralization and the resulting increase in callus size with Wnt surrogate treatment is evident at both 1 and 6 weeks of treatment. One week was sufficient to induce rapid mineralization that could predict rapid fracture healing and resistance to fracture. 1RCO7-3 appeared to induce mineralization to a greater extent than R2M3-26. Radiographs taken 6 weeks after treatment showed persistence of highly mineralized callus in the 1RCO7-3 group, while the portion of the fracture callus in the R2M3-26 group was reduced (FIGS. 33B and D).

[0279] Whole body DEXA was measured throughout the experiment to examine bone mineral density in the fractured femur as well as the contralateral unfractured femur, and the expected increase in bone mineral density occurred after treatment (Figures 33C and D). This reduces the risk of secondary fractures in the already fractured limb and appendicular skeleton. The BMD of the contralateral femur at time 42 is shown in Figure 33C.

[0280] Six weeks after treatment following callus identification, femurs were scanned by micro-computed tomography to determine multiple parameters associated with increased resistance to fracture after healing. There was a significant increase in callus tissue volume within the examined target area, bone volume within the callus, and especially bone mineral content (Figure 33D). Qualitatively, the reconstructs show thick osteoid and mineral prevalence within the treated fracture. These parameters suggest robust resistance to fracture and also indicate that delayed treatment with Wnt surrogate molecules following spontaneous chondral callus formation can initiate a rapid and significant increase in bone formation.

[0281] In another experiment, dosing schedules were tested to determine whether Wnt surrogate molecule therapy could induce a significant bone anabolic effect, how long that effect lasted, and how bone responded to further treatment after drug withdrawal. Systemic skeletal effects were compared with variable dosing of 1RCO7-3 for anabolic effects, drug withdrawal, and rechallenge after baseline establishment. 12-week-old C57BL / 6 females (n=8 / group) were injected ip with recombinant Wnt surrogate molecules with the following experimental groups: 2 groups with 1RCO7-3, 1 with anti-bgal (antibody control), and 1 with vehicle (PBS) on day 0 of the experiment. For comparison, another cohort of mice was injected subcutaneously with romosozumab on day 0 (romosozumab is an anti-sclerostin antibody that can reverse bone loss associated with osteoporosis (Saag et al., N Engl J Med. 2017 Oct 2017). 12;377(15):1417-1427; PMID:28892457). The 1RC07-3 treated animals had a significant and rapid induction of bone formation by day 14 (Figure 34). One group was administered a second injection on day 14 to determine if the bone anabolic effect could be further enhanced. Interestingly, all treatment effects were reversed and normalized after 35 days, regardless of treatment. A two-week period was allowed to return to baseline levels before the second round of treatment. At day 49, all experimental Groups were given a second round of treatment. Wnt surrogate-treated animals responded quickly, but not to the same extent as the first treatment (Figure 34). In all groups, new bone formation ceased 5 weeks after the last injection, indicating that a single injection can significantly increase bone formation, but the anabolic effect is quickly lost. This suggests that antiresorptive agents may be required in combination with Wnt surrogate therapy to maintain the anabolic effect.

[0282] The mechanism of action of romosozumab relies on stimulating bone formation by removing an inhibitor of endogenous Wnt signaling (sclerostin). Animals were treated with Wnt surrogate molecules and romosozumab to determine whether Wnt surrogate molecule treatment could synergize with romosozumab in a combination study.

[0283] Ten week old C57BL / 6 males (n=8 / group) were injected ip with combinations of recombinant Wnt surrogate molecules and romosozumab in the following experimental groups: 1RC07-3 (0.1 mpk), 1RCO7-3 (1 mpk), 1RCO7-3 (10 mpk), 1RCO7-3 (0.1 mpk) + romosozumab (25 mpk), 1RCO7-3 (1 mpk) + romosozumab (25 mpk), 1RCO7-3 (10 mpk) + romosozumab (25 mpk), romosozumab (25 mpk) alone, anti-Bgal (antibody control), and vehicle (PBS). Animals were treated twice weekly and followed for 3 weeks.

[0284] Total body BMD was measured weekly. The results are shown in Figure 35. The conclusion of this study is that endogenous romosozumab can stimulate further bone growth in the presence of high doses of 1RC07-3. These data further suggest that peak anabolic effects have not yet been reached with 10mpk 1RCO7-3 treatment. These data also show that romosozumab can stimulate bone formation even in the presence of 1RCO7-3. Overall, this study shows that Wnt surrogate molecule treatment can cooperate with romosozumab to enhance bone anabolic effects after only 21 days of twice weekly treatment.

[0285] Changes in gene expression in whole bone were measured over a time course following Wnt surrogate molecule therapy in mice to assess how this therapy controls the expression of gene markers associated with proliferation and bone formation. 13-week-old C57BL / 6 females (n=5 / group) were given a single ip injection of 1RCO7-3 or anti-Bgal (antibody control). For comparison, another cohort of mice received a subcutaneous injection of romosozumab. Cohorts of animals were sacrificed 8, 24, 48, and 120 hours after treatment, and tibiae and serum were isolated and snap frozen for RNA extraction. ELISA was used to measure the levels of therapeutic molecules in serum over the course of the experiment as described above (Figure 36).

[0286] For RNA purification from bone, excised tibiae from freshly killed animals were processed as follows: both ends of the tibia were cut to expose the medullary cavity, which was flushed with ice-cold saline through a 30-gauge needle. Steps were taken to ensure that all muscle tissue and cartilage were removed. The bone appeared completely white, with no red marrow components remaining. The tibiae were placed in a 1.5 mL Eppendorf tube and flash frozen in liquid nitrogen. For lysis, a single tissue lysis bead was placed in the tube containing the bone, and Trizol was added directly to the frozen bone and beads. A high-speed tissue lyser was used to completely homogenize. The homogenate was then subjected to chloroform extraction to separate the nucleic acid phase. Further isolation and purification was performed using the RNeasy mini kit (Quagen).

[0287] RNA isolated from tibiae was tested for relative transcript levels of Runt-related transcription factor 2 (RunX2), collagen type I alpha 1 chain (Col1A1), dentin matrix acidic phosphoprotein 1 (Dmp1), alkaline phosphatase (Alp), receptor activator of nuclear factor kappa B (RankL), Dickkopf inhibitor of WNT signaling pathway 1 (Dkk1), sclerostin (Sost), cyclin D1 (Ccnd1), axin 2, and Ki67. [Table 4]

[0288] Compared to anti-sclerostin antibody (romosozumab) treatment, gene expression signatures across time points were distinct in Wnt surrogate molecular therapy, inducing more robust Axin2 and Ki67 expression than did romosozumab treatment.

[0289] Example 22 In vivo liver regeneration model and characterization of AAV-delivered Wnt surrogates In vivo experiments were performed by infecting approximately 8-week-old C57BL / 6J mice with an AAV vector expressing Flag- and His-tagged 18R5-DKK1c protein (AAV-18R5-DKK1c-FlagHis). 18R5-DKK1c is a fusion protein containing the frizzled binding antibody 18R5 in scFv format fused to DKK1c (described in PCT Publication No. WO2016 / 040895 (e.g., FIG. 5)). Control mice were subcutaneously injected with phosphate-buffered saline (PBS) alone or romosozumab (10 mg / kg), or intravenously (IV) with an AAV vector expressing green fluorescent protein (GFP) (AAV-CAG-GFP) or an AAV vector expressing a fusion protein containing an anti-GFP scFV fused to mutant DKK1c (AAV-ScFv(anti-GFP)-DKK1cF234K-Flag-His). 28 days after infection, animals were weighed and sacrificed. Livers were weighed and liver-to-body weight ratios were calculated. Small intestine and colon were flushed with phosphate buffered saline and the contents were removed by gentle squeezing to expel the contents. Small intestine and colon contents were then weighed.

[0290] Systemic expression of 18R5-DKK1c-FlagHis resulted in a significant increase in liver weight (Figure 37A). Systemic expression of the negative control eGFP or anti-eGFP-Dkk1cF234K did not affect liver-to-body weight ratio. Administration of romosozumab recombinant protein or vehicle control did not affect liver-to-body weight ratio.

[0291] None of the treatments affected the small intestine (Figure 37B) or colon (Figure 37C) to body weight ratios.

[0292] These studies showed that 18R5-DKK1c-FlagHis increased liver weight, but not the weight of the small or large intestine, suggesting that 18R5-DKK1c-FlagHis may promote liver regeneration.

[0293] Example 23 In vivo liver regeneration model and characterization of recombinantly produced Wnt surrogates In vivo experiments were performed by treating mice with various doses of recombinantly produced anti-eGFP, R2M3-26, 1R-C07-26, romosozumab, or Rspo2 protein, a fusion protein of a short splice variant of the Rspo2 gene and a human Fc fragment.

[0294] In one study, mice were housed 4 per cage with n=8 per treatment group. Approximately 8-week-old C57BL6 / J mice were intraperitoneally (ip) administered recombinant protein anti-eGFP (1 mg / kg), R2M3-26 (1 or 10 mg / kg), or 1R-C07-26 (1, 5, or 10 mg / kg) twice weekly for 4 weeks. In addition, groups of mice were subcutaneously administered romosozumab (30 mg / kg) or PBS vehicle control.

[0295] Mice were weighed at the beginning and throughout the treatment. None of the treatments with recombinant proteins significantly affected total body weight (Figure 38A). Livers were weighed on day 28 and liver-to-body weight ratios were calculated (Figure 38B). The highest dose of R2M3-26 (10 mg / kg) resulted in a significant increase in liver-to-body weight ratio. None of the other treatments significantly affected liver weight.

[0296] The increase in liver weight in response to R2M3-26 suggests that this recombinant protein may promote liver regeneration.

[0297] In another study, mice were housed 5 per cage with n = 10 per treatment group. Approximately 8-week-old C57BL / 6J mice were administered a single ip injection containing anti-eGFP (0.56 mg / kg), R2M3-26 (0.3 mg / kg), or Rspo2 (0.46 mg / kg) alone or in combination with R2M3-26 (0.1 mg / kg) and Rspo2 (0.46 mg / kg).

[0298] Mice were euthanized 24 or 48 hours after injection. A portion of the left liver lobe was snap frozen in liquid nitrogen and stored at -80°C for RNA analysis. Cyclin D1 and Ki67 expression was measured by performing qPCR using Mm00432359_m1 Ccnd1 probe and Mm01278617_m1 Ki67 probe (Thermofisher, 4331182). An additional portion of the left liver lobe was fixed in formalin and embedded in paraffin for immunohistochemical analysis. Sections were stained with anti-proliferating cell nuclear antigen (PCNA) (Abcam, ab18197) or anti-phosphohistone H3 (pH3) rabbit antibody (Abcam, ab47297). The number of positive nuclei was counted using the image processing software Image J.

[0299] Rspo2 alone increased the mRNA expression of Ki67 (FIG. 39A) and cyclin D1 (FIG. 39B). When combined with R2M3-26, Rspo2 increased the expression of Ki67 and cyclin D1 more than Rspo2 alone 24 and 48 hours after treatment with recombinant protein. Rspo2 alone increased the number of PCNA (FIG. 39C) and pH3 (FIG. 39D) positive nuclei in liver sections. When combined with R2M3-26, Rspo2 increased the number of PCNA and pH3 positive nuclei more than Rspo2 alone 48 hours after treatment with recombinant protein.

[0300] These studies showed that proliferation markers Ki67 mRNA, cyclin D1 mRNA, and PCNA positive nuclei, as well as the pH3 mitotic marker, were induced by R2M3-26 and Rspo2 recombinant proteins, suggesting that these recombinant proteins may promote liver regeneration.

[0301] Example 24 In vivo chronic liver injury model and characterization of AAV-delivered Wnt surrogates Two in vivo experiments in two mouse models of cirrhosis induced by thioacetamide (TAA) and CCl4 were performed to test the effect of AAV vectors expressing 18R5-DKK1c-FlagHis or Rspo2 proteins on chronic liver injury. TAA was added to the drinking water of 6-week-old C57BL / 6J mice at a concentration of 300 mg / L throughout the TAA treatment period. Mice were housed 5 per cage, with n=10 used, except for the control group without TAA treatment, where n=5 per group was used.

[0302] In study 1 (Figures 40A, 40C, 40E, 40G-H), mice with (n=10) or without (n=5) TAA treatment were weighed and sacrificed 9 weeks after TAA supplementation in drinking water to measure baseline values. Livers were weighed and liver samples were collected for mRNA and histological analysis. The remaining mice maintained TAA supplementation in their drinking water and were IV injected with AAV vectors expressing enhanced green fluorescent protein (eGFP) (3e10 genome particles (GC)), 18R5-DKK1c-FlagHis (3e10 or 1e11 GC), or Rspo2 protein (1e11 GC), or a combination of 18R5-DKK1c-FlagHis (3e10 GC) and Rspo2 (1e11 GC). Five age-matched naïve animals (without TAA) were kept as negative controls. Three weeks after AAV injection, all mice were weighed and euthanized. Livers were weighed and liver samples were collected for mRNA and histological analysis.

[0303] Treatment with 18R5Dkk1FH or Rspo2 resulted in a significant increase in liver weight (Figure 40C) and liver-to-body weight ratio (Figure 40E) in mice undergoing continuous exposure to TAA. Treatment with a combination of 18R5Dkk1FH and Rspo2 resulted in a further increase in liver weight and liver-to-body weight ratio beyond that observed with either treatment alone. Combined treatment with 18R5Dkk1FH and Rspo2 resulted in a decrease in Col1a1 mRNA expression, a fibrotic marker (Figure 40G). Histological liver sections were stained with Sirius Red to visualize collagen accumulation within fibrotic areas (Figure 40H). Image Quantification of the percentage of red using J-analysis software showed a significant increase in fibrotic area in TAA-treated mice. The combination of 18R5Dkk1FH and Rspo2 resulted in a recovery from the increased fibrotic area when compared to mice treated with eGFP negative control. Treatment with Rspo2 alone also resulted in a significant recovery, but less than the combination treatment.

[0304] In study 2 (Figures 40B, 40D, 40F), mice were exposed to TAA-supplemented water for 11 weeks and then returned to standard drinking water 2 days before AAV treatment. At the start of AAV treatment, TAA-exposed (n=10) or unexposed (n=5) mice were weighed and sacrificed to collect liver samples for baseline measurements. The remaining mice were injected with AAV vectors expressing enhanced green fluorescent protein (eGFP) (1.3e11 genome particles (GC)), 18R5-DKK1c-FlagHis (3e10 or 1e11 GC), or Rspo2 protein (1e11 GC), or a combination of 18R5-DKK1c-FlagHis (3e10 GC) and Rspo2 (1e11 GC). Five age-matched naïve animals (without TAA) were kept as negative controls. Three weeks after AAV injection, all mice were weighed and euthanized. Livers were weighed and liver samples were collected for mRNA and histological analysis.

[0305] Similar increases in liver weight and liver-to-body weight ratios as observed in Study 1 were observed in mice treated with 18R5-DKK1c-FlagHis and Rspo2, either alone or in combination (FIGS. 40D, 40F).

[0306] These studies show that 18R5-DKK1c-FlagHis and Rspo2 can increase liver weight and reduce fibrosis markers in a TAA-induced liver cirrhosis model. These results suggest that 18R5-DKK1c-FlagHis and Rspo2 can promote liver tissue repair after chronic liver injury.

[0307] Example 25 In vivo chronic liver injury model and characterization of recombinantly produced Wnt surrogates In vivo experiments were performed in thioacetamide (TAA)-induced and CCl4-induced mouse models of liver cirrhosis by treating mice with recombinantly produced anti-eGFP, R2M3-26, and Rspo2 proteins.

[0308] In the TAA-induced liver cirrhosis model, 6-week-old male mice were exposed to TAA-supplemented drinking water (300 mg / L) for approximately 22 weeks (Figure 41A). TAA exposure was removed 2 days before treatment with recombinant proteins was initiated, and mice were provided with fresh drinking water. Mice were housed 5 per cage, with n=10 per treatment group. In single treatment studies (Figures 41B, 41D, 41F, 41H, 41J, 41L), mice were injected ip twice weekly with anti-eGFP (1 mg / kg) or Rspo2 (1 mg / kg). In combination treatment studies (Figures 41C, 41E, 41G, 41I, 41K, 41M), mice were injected ip twice weekly with anti-eGFP (1.3 mg / kg) or a combination of R2M3-26 (0.3 mg / kg) and Rspo2 (1 mg / kg). Mice were then weighed and sacrificed on days 3, 7, or 14 after the start of treatment. Control groups of mice (n=5 per group) without exposure to TAA were euthanized on days 0 and 14 of both studies.

[0309] Treatment with Rspo2 protein alone or in combination with R2M3-26 resulted in increased liver-to-body weight ratio (Figures 41B and 41C) and transient stimulation of the Wnt signaling pathway as indicated by increased Axin2 expression (Figures 41D and 41E). Treatment with Rspo2 protein alone or in combination with R2M3-26 induced the following proliferation markers: cyclin D1 (Figures 41F, 41G) and Ki67 (Figures 41H and 41I) mRNA expression, PCNA (Figures 41J, 41K) and pH3 (Figures 41L, 41M) positive nuclei.

[0310] In further studies, plasma was collected for prothrombin time measurements. Clotting time was impaired in the TAA-induced cirrhosis model, as illustrated by an increased ratio of prothrombin (PT) test to normal values ​​in mice exposed to TAA when compared to normal mice without TAA exposure (Figure 41N). Treatment with Rspo2 (1 mg / kg) and R2M3-26 (0.3 mg / kg) significantly improved PT at 7 and 14 days after twice weekly Rspo2 and R2M3-26 treatment. 試験 / PT 正常 The prolongation of PT time was restored as indicated by the decrease in the ratio.

[0311] These studies indicate that Rspo2 and R2M3-26 can stimulate liver cell proliferation and improve liver cell functional activities, such as prothrombin time, in a TAA-induced liver cirrhosis model. These results suggest that Rspo2 and R2M3-26 may promote liver tissue repair in chronic liver disease. ...

Claims

1. A soluble, tetravalent and bispecific Wnt surrogate molecule comprising: (i) two Frizzled (Fzd) binding regions that specifically bind to two Fzd receptors, each of the two Fzd binding regions comprising an antibody or an antigen-binding fragment of the antibody; (ii) two LRP5 / 6 binding regions that specifically bind low density lipoprotein (LDL) receptor-related protein 5 (LRP5) and / or low density lipoprotein (LDL) receptor-related protein 6 (LRP6), each of the two LRP5 / 6 binding regions comprising an antibody or an antigen-binding fragment of the antibody; A Wnt surrogate molecule comprising:

2. The Wnt surrogate molecule of claim 1, wherein the Fzd binding region comprises a whole immunoglobulin (Ig) containing two light chains and two heavy chains, and the LRP5 / 6 binding region comprises a VHH.

3. The Wnt surrogate molecule of claim 2, wherein each of the two LRP5 / 6 binding regions is fused to the N-terminus of one of the light chains.

4. The Wnt surrogate molecule of claim 3, wherein each of the two LRP5 / 6 binding regions is fused to one of the light chains via a linker moiety.

5. A pharmaceutical composition comprising a physiologically acceptable excipient, diluent or carrier and a therapeutically effective amount of the Wnt surrogate molecule of claim 1.

6. The Wnt surrogate molecule of claim 1 , wherein the LRP5 / 6 binding region is not the C-terminal portion of DKK.

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