Wnt signaling agonist molecules

Abstract

Wnt signaling agonist compositions and methods for their use are provided. Wnt signaling agonists of the invention comprise a frizzled binding moiety, which is fused or conjugated to an LRP5 or LRP6 binding moiety.

What is claimed is: 
     
         1 . A water soluble canonical Wnt signaling agonist that dimerizes a Frizzled (Fzd) receptor with Lrp5/6. 
     
     
         2 . The Wnt signaling agonist of  claim 1 , wherein the agonist directly activates canonical wnt signaling. 
     
     
         3 . The wnt signaling agonist of  claim 2 , wherein the molecule comprises a polypeptide. 
     
     
         4 . The wnt signaling agonist of  claim 3 , wherein the polypeptide comprises a binding domain having a high affinity for one or more Fzd proteins; and a binding domain having high affinity to one or both of Lrp5 and Lrp6 protein. 
     
     
         5 . The wnt signaling agonist of  claim 4 , wherein the binding domains are directly joined. 
     
     
         6 . The wnt signaling agonist of  claim 4 , wherein the binding domains are joined through a linker. 
     
     
         7 . The wnt signaling agonist of any of  claims 1 - 6 , wherein the surrogate enhances β-catenin signaling by at least 50% compared to the β-catenin signaling induced by a neutral substance or negative control. 
     
     
         8 . The wnt signaling agonist of  claim 7 , wherein the surrogate enhances β-catenin signaling by a factor of at least 10× compared to the β-catenin signaling induced by a neutral substance or negative control. 
     
     
         9 . The wnt signaling agonist of  claim 7 , wherein the surrogate enhances β-catenin signaling by a factor of at least 1000× compared to the β-catenin signaling induced by a neutral substance or negative control. 
     
     
         10 . The wnt signaling agonist of any of  claims 7 - 9 , wherein the surrogate enhances β-catenin signaling in a human cell. 
     
     
         11 . The wnt signaling agonist of  claim 4 , wherein the Fzd binding domain binds one or more Fzd proteins with a K D  of at least about 1×10 −7  M. 
     
     
         12 . The wnt signaling agonist of  claim 11 , wherein the Fzd binding domain is a polypeptide. 
     
     
         13 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain is a de novo designed Fzd binding domain. 
     
     
         14 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain is an antibody derived binding protein. 
     
     
         15 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain is a nanobody derived binding domain. 
     
     
         16 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain is a knottin-engineered scaffold. 
     
     
         17 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domains is a norrin protein or binding fragment derived therefrom. 
     
     
         18 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain has been affinity selected for a desired specificity. 
     
     
         19 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain binds to two or more different frizzled proteins. 
     
     
         20 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain is selective for a frizzled protein of interest. 
     
     
         21 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain is an scFv comprising the six CDR regions of an anti-Fzd antibody. 
     
     
         22 . The wnt signaling agonist of  claim 12 , wherein the Fzd binding domain is an scFv comprising the six CDR regions of pan-specific frizzled antibody OMP-18R5. 
     
     
         23 . The wnt signaling agonist of  claim 4 , wherein the Lrp5/6 binding domain binds one or both of Lrp5 and Lrp6 proteins with a K D  of at least about 1×10 −7  M. 
     
     
         24 . The wnt signaling agonist of  claim 23 , wherein the Lrp5/6 binding domain is a polypeptide. 
     
     
         25 . The wnt signaling agonist of  claim 23 , wherein the Lrp5/6 binding domain is a de novo designed Fzd binding domain. 
     
     
         26 . The wnt signaling agonist of  claim 23 , wherein the Lrp5/6 binding domain is an antibody derived binding protein. 
     
     
         27 . The wnt signaling agonist of  claim 23 , wherein the Lrp5/6 binding domain is a nanobody derived binding domain. 
     
     
         28 . The wnt signaling agonist of  claim 23 , wherein the Lrp5/6 binding domain is a knottin-engineered scaffold. 
     
     
         29 . The wnt signaling agonist of  claim 23 , wherein the Lrp5/6 binding domain comprises a binding portion of a DKK protein. 
     
     
         30 . The wnt signaling agonist of  claim 29 , wherein the Lrp5/6 binding domain comprises the C-terminal domain of human DKK1. 
     
     
         31 . The wnt signaling agonist of any one of  claims 1 - 30  wherein the binding domains are joined by a peptide linker comprising from 2-100 amino acids. 
     
     
         32 . The wnt signaling agonist of  claim 31 , wherein the linker enforces a distance between binding domains of less than about 100 angstroms. 
     
     
         33 . The wnt signaling agonist of any one of  claims 1 - 30 , wherein the binding domains are joined by a non-peptide linker. 
     
     
         34 . A pharmaceutical composition comprising a wnt signaling agonist of any one of  claims 1 - 33 , and a pharmaceutically acceptable excipient. 
     
     
         35 . A method of activating or enhancing wnt signaling, the method comprising contacting a cell expressing a frizzled receptor with an effective dose of a wnt signaling agonist according to any one of  claims 1 - 33 . 
     
     
         36 . A method of treating or preventing a disease or disorder in a subject in need thereof, the method comprising providing to the subject an effective amount of a wnt signaling agonist according to any one of  claims 1 - 33 . 
     
     
         37 . The method of  claim 36 , wherein the subject has a disease or disorder associated with reduced wnt signaling. 
     
     
         38 . The method of  claim 36  or  claim 37 , wherein the subject has a disease or disorder selected from radiation/chemotherapy injury, mucositis, inflammatory bowel diseases, short bowel syndrome, hereditary bowel disorders, celiac disease, metabolic diseases, hereditary syndromes, viral infections (e.g., hepB/C), toxic states, alcoholic liver, fatty liver, cirrhosis, infections, pernicious anemia, ulceration, diabetes, diabetic foot ulcers (e.g., refractory diabetic foot ulcers), destruction of islet cells, loss of bone mass (osteoporosis), loss of functional skin, loss of hair, loss of functional lung tissue, loss of kidney tissue (for instance acute tubulus necrosis), loss of sensory cells in the inner ear, joint disorder, osteoporosis and related bone diseases, baldness, and graft-versus-host disease. 
     
     
         39 . A method of enhancing wound healing and/or tissue generation in a subject in need thereof, the method comprising providing to the subject an effective amount of a wnt signaling agonist according to any one of  claims 1 - 33 .