Cryptic polypeptides and uses thereof

Abstract

The disclosure features, among other things, polypeptides comprising a Cryptic polypeptide, a functional fragment thereof, or variants of any of the foregoing. Also featured are nucleic acids encoding the polypeptides, methods for producing of the polypeptides, and a variety of diagnostic and therapeutic applications in which the polypeptides are useful. For example, the polypeptides can be used to treat a subject having a condition associated with bone loss.

1 . A polypeptide comprising: (i) the amino acid sequence depicted in any one of SEQ ID NOs:1 to 9, 19, or 20; (ii) a variant of the amino acid sequence depicted in any one of SEQ ID NOs: 1 to 9, 19, or 20 having not more than 10 amino acid substitutions, deletions, or insertions; or (iii) an amino acid sequence that is at least 80% identical to any one of the amino acid sequences depicted in SEQ ID NOs: 1 to 9, 19, or 20. 
     
     
         2 . The polypeptide of  claim 1 , wherein the polypeptide comprises the amino acid sequence depicted in SEQ ID NO:7-9, 19, or 20. 
     
     
         3 . The polypeptide of  claim 1 , wherein the polypeptide comprises an amino acid sequence comprising any one of SEQ ID NOs: 4 to 9, and wherein the amino acid sequence of the polypeptide is at least 80% identical to SEQ ID NO: 1 or 2. 
     
     
         4 . The polypeptide of  claim 1 , wherein the polypeptide binds to human Activin A with a K D  selected from the group consisting of less than 1×10 −9 M, 1×10 −10  M, and 1×10 −11 M. 
     
     
         5 - 6 . (canceled) 
     
     
         7 . The polypeptide of  claim 1 , wherein the polypeptide has at least 30% of the ability of wild-type human Cryptic to inhibit human Activin A-dependent cell signaling in vitro or B-dependent cell signaling in vitro. 
     
     
         8 . The polypeptide  claim 1 , wherein the polypeptide binds to human Activin B with a K D  of less than 1×10 −9 M or 5×10 −10  M. 
     
     
         9 - 10 . (canceled) 
     
     
         11 . The polypeptide of  claim 1 , wherein the polypeptide comprises a heterologous moiety that increases the serum half-life of the peptide in a subject. 
     
     
         12 . The polypeptide of  claim 11 , wherein the heterologous moiety comprises an immunoglobulin Fc constant region having an amino acid sequence selected from the group consisting of SEQ ID NO: 21, SEQ ID NO: 10, SEQ ID NO: 19, and SEQ ID NO: 20. 
     
     
         13 - 15 . (canceled) 
     
     
         16 . The polypeptide of  claim 11 , wherein the heterologous moiety comprises all or a portion of an albumin protein or polyethylene glycol. 
     
     
         17 . (canceled) 
     
     
         18 . The polypeptide of  claim 1 , wherein the polypeptide comprises a heterologous moiety that targets the polypeptide to bone wherein said moiety comprises the formula: X n , wherein X is a canonical or noncanonical amino acid that has a negative charge at physiological pH and n is an integer from 1 to 25, and wherein said amino acid is aspartic acid or glutamic acid. 
     
     
         19 - 20 . (canceled) 
     
     
         21 . The polypeptide of  claim 18 , wherein n is an integer between 5 and 15 or 10 and 16. 
     
     
         22 . (canceled) 
     
     
         23 . The polypeptide of  claim 1 , wherein the polypeptide comprises a detectable label. 
     
     
         24 . A method for increasing bone growth, bone strength, or bone density in a subject in need thereof, the method comprising administering to the subject one or more of any one of the polypeptides according to  claim 1  in an amount sufficient to increase bone growth, bone strength, or bone density in the subject. 
     
     
         25 . The method of  claim 24 , wherein the subject has a condition associated with bone loss. 
     
     
         26 . The method of  claim 25 , wherein the condition is selected from the group consisting of osteoporosis, Paget's disease, rheumatoid arthritis, periodontal disease, bone fracture, bone deficiency, metastatic bone disease, osteoarthritis, primary or secondary hyperparathyroidism, and osteolytic bone disease. 
     
     
         27 - 28 . (canceled) 
     
     
         29 . The method of  claim 26 , wherein the periodontal disease is gingivitis or periodontitis. 
     
     
         30 . The method of  claim 24 , wherein, following administration, the composition improves a bone parameter selected from the group consisting of bone volume density, total bone surface, bone surface density, trabecular number, trabecular thickness, trabecular spacing, and total volume. 
     
     
         31 . The method of  claim 24 , further comprising monitoring the subject for an improvement in any one of the following bone parameters: bone volume density, total bone surface, bone surface density, trabecular number, trabecular thickness, trabecular spacing, or total volume. 
     
     
         32 . The method of  claim 24 , further comprising administering to the subject at least one additional therapeutic agent that promotes bone growth or inhibits bone resorption. 
     
     
         33 . A method for increasing muscle mass or muscle strength in a subject in need thereof, the method comprising administering to the subject one or more of any of the polypeptides according to  claim 1  in an amount sufficient to increase muscle mass or muscle strength in the subject. 
     
     
         34 . The method of  claim 33 , wherein the subject has a muscle wasting disorder. 
     
     
         35 . A method for treating a subject having a muscle-wasting disorder or muscle atrophy, the method comprising administering to the subject one or more of any of the polypeptides according to  claim 1  in an amount sufficient to treat the muscle-wasting disorder or muscle atrophy. 
     
     
         36 . The method of  claim 34  or  35 , wherein the muscle-wasting condition is, or is associated with, Duchenne muscular dystrophy (DMD), multiple types of limb girdle MD (LGMD), other congenital MDs (CMD), sarcopenia, cancer cachexia, or Diabetes mellitus. 
     
     
         37 . A method for treating a musculoskeletal disorder in a subject, the method comprising administering to the subject one or more of any of the polypeptides according to  claim 1  in an amount sufficient to treat the musculoskeletal disorder. 
     
     
         38 . The method of  claim 37 , wherein the musculoskeletal disorder is: (i) osteoporosis, (ii) osteopenia, (iii) sarcopenia, (iv) arthritis, (v) tissue atrophy, (vi) periodontal disease, (vii) wound healing, or (viii) bone loss due to malignancy, endocrine disorders, arthritis, immobility, or disuse. 
     
     
         39 . A method for treating a subject having a metabolic disorder, the method comprising administering to the subject one or more of any of the polypeptides according to  claim 1  in an amount sufficient to treat the metabolic disorder. 
     
     
         40 . The method of  claim 39 , wherein the metabolic disorder is type 2 diabetes, noninsulin-dependent diabetes mellitus, hyperglycemia, and obesity. 
     
     
         41 . A method for treating a subject having a cancer, the method comprising administering to the subject one or more of any of the polypeptides according to  claim 1  in an amount sufficient to treat the cancer. 
     
     
         42 . The method of  claim 41 , wherein the cancer comprises cancer cells that express one or more receptors for Activin A or Activin B. 
     
     
         43 . The method of  claim 42 , wherein one or both of the proliferation and viability of the cancer cells is positively regulated by Activin A or Activin B. 
     
     
         44 . The method of  claim 41 , wherein the cancer is a lung cancer, breast cancer, colon cancer, pancreatic cancer, renal cancer, stomach cancer, liver cancer, bone cancer, hematological cancer, neural tissue cancer, melanoma, thyroid cancer, ovarian cancer, testicular cancer, prostate cancer, cervical cancer, vaginal cancer, or bladder cancer. 
     
     
         45 . The method of any one of  claim 24 ,  33 ,  35 ,  37 ,  39 , or  41 , wherein the polypeptide is administered to the subject intravenously or subcutaneously. 
     
     
         46 . (canceled) 
     
     
         47 . The method of any one of  claim 24 ,  33 ,  35 ,  37 ,  39 , or  41 , wherein the subject is a human. 
     
     
         48 . A fusion polypeptide, comprising:
 an N-terminal region comprising a signal peptide sequence from a cryptic protein or a functional variant or fragment thereof; and   a fragment of a human Cripto-1 protein comprising:
 an EGF domain; and 
 a CFC domain.