CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Serial No. 62/022,516, filed July 9, 2014. This disclosure of the prior application is considered part of (and is incorporated by reference in) the disclosure of this application.

BACKGROUND

1. Technical Field

This document provides methods and materials related to treating rotator cuff conditions (e.g., rotator cuff tendonitis or rotator cuff injuries such as partial or complete rotator cuff tears). For example, this document provides methods and materials for using BMP-5 polypeptides and/or inhibitors of SIRT6, SIRT7, and/or HDAC10 polypeptide expression or activity to treat rotator cuff conditions.

2. Background Information

The rotator cuff is a group of muscles and tendons that surround the shoulder joint, keeping the head of your upper arm bone firmly within the shallow socket of the shoulder. A rotator cuff injury can cause pain as well as loss of shoulder function.

SUMMARY

This document provides methods and materials related to treating rotator cuff conditions (e.g., rotator cuff tendonitis or rotator cuff injuries such as partial or complete rotator cuff tears). For example, this document provides methods and materials for using BMP-5 polypeptides to treat rotator cuff conditions. In some cases, a composition that includes BMP-5 polypeptides and/or cells (e.g., stem cells) designed to express BMP-5 polypeptides can be administered to (e.g., injected into) the rotator cuff region of a mammal suffering from a rotator cuff condition. In some cases, a composition that includes BMP-5 polypeptides and/or cells (e.g., stem cells) designed to express BMP-5 polypeptides can be introduced at the time of a surgical repair. In such cases, the administered (e.g., injected) composition can reduce or reverse tendon degeneration, enhance healing, and/or increase tendon strength.

This document also provides methods and materials for using inhibitors of

SIRT6, SIRT7, and/or HDAC10 polypeptide expression or activity to treat rotator cuff conditions. In some cases, a composition that includes one or more inhibitors of SIRT6, SIRT7, and/or HDACIO polypeptide expression or activity can be administered to (e.g., injected into) the rotator cuff region of a mammal suffering from a rotator cuff condition. In such cases, the administered (e.g., injected) composition can reduce or reverse tendon degeneration, enhance healing, and/or increase tendon strength. In some cases, inhibitors of SIRT6, SIRT7, and/or

HDACIO polypeptide expression or activity can be used alone or in conjunction with BMP-5 polypeptides to treat a rotator cuff condition. For example, an inhibitor of HDACIO expression can be combined with a BMP-5 polypeptide to form a composition that is used to treat a mammal suffering from a rotator cuff condition.

In general, one aspect of this document features a method for treating a mammal having a rotator cuff condition. The method comprises, or consists essentially of, injecting a composition comprising a BMP-5 polypeptide into a rotator cuff region of the mammal, wherein injection of the composition reduces or reverses tendon degeneration, enhances tendon healing, or increases tendon strength. The mammal can be a human. The rotator cuff condition can be a rotator cuff condition wherein a rotator cuff tendon is partially torn. The rotator cuff condition can be a rotator cuff condition wherein a rotator cuff tendon is ruptured. The rotator cuff condition can be rotator cuff tendonitis. The injection can be an intra-articular injection into a joint space. The injection can be an injection into a subacromial space. The injection can be a direct injection into a damaged tendon. The BMP-5 polypeptide can be a human BMP-5 polypeptide. The BMP-5 polypeptide can comprise the amino acid sequence set forth in SEQ ID NO: 1.

In another aspect, this document features a method for treating a mammal having a rotator cuff condition. The method comprises, or consists essentially of, administering a composition into a rotator cuff region of the mammal, wherein composition comprises cells comprising an exogenous nucleic acid encoding a BMP- 5 polypeptide, wherein the cells express the BMP-5 polypeptide, and wherein administration of the composition reduces or reverses tendon degeneration, enhances tendon healing, or increases tendon strength. The mammal can be a human. The rotator cuff condition can be a rotator cuff condition wherein a rotator cuff tendon is partially torn. The rotator cuff condition can be a rotator cuff condition wherein a rotator cuff tendon is ruptured. The rotator cuff condition can be rotator cuff tendonitis. The administration can be an intra-articular injection into a joint space. The administration can be an injection into a subacromial space. The administration can be a direct injection into a damaged tendon. The BMP-5 polypeptide can be a human BMP-5 polypeptide. The BMP-5 polypeptide can comprise the amino acid sequence set forth in SEQ ID NO: 1.

In another aspect, this document features a method for treating a mammal having a rotator cuff condition. The method comprises, or consists essentially of, administering a composition to a rotator cuff region of the mammal, wherein the composition comprises an inhibitor of SIRT6, SIRT7, or HDAC10 polypeptide expression or activity, wherein administration of the composition reduces or reverses tendon degeneration, enhances tendon healing, or increases tendon strength. The mammal can be a human. The rotator cuff condition can be a rotator cuff condition wherein a rotator cuff tendon is partially torn. The rotator cuff condition can be a rotator cuff condition wherein a rotator cuff tendon is ruptured. The rotator cuff condition can be rotator cuff tendonitis. The administration can be an intra-articular injection into a joint space. The administration can be an injection into a subacromial space. The administration can be a direct injection into a damaged tendon. The composition can comprise an inhibitor of SIRT6 polypeptide expression or activity. The composition can comprise an inhibitor of SIRT7 polypeptide expression or activity. The composition can comprise an inhibitor of HDAC10 polypeptide expression or activity (e.g., CUDC-907, pracinostat, abexinostat, or quisinostat). The composition can further comprise a BMP-5 polypeptide. The composition can further comprise cells comprising an exogenous nucleic acid encoding a BMP-5 polypeptide, wherein the cells express the BMP-5 polypeptide.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

Figure 1 is a graph plotting the level of BMP 5 expression is various tissue types including bone, cartilage, muscle, tendon (supraspinatus, subscapularis, patellar tendon, posterior tibial tendon, and Achilles tendon), and ligament.

Figure 2 is an amino acid sequence (SEQ ID NO: 1) listing of a human BMP-5 polypeptide.

Figure 3 is a nucleotide sequence (SEQ ID NO:2) listing of a nucleic acid that encodes a BMP-5 polypeptide.

DETAILED DESCRIPTION

This document provides methods and materials related to using BMP-5 polypeptides, cells expressing BMP-5 polypeptides, inhibitors of SIRT6 polypeptide expression or activity, inhibitors of SIRT7 polypeptide expression or activity, inhibitors of HDAC10 polypeptide expression or activity, or combinations thereof to treat rotator cuff conditions. For example, a composition that includes BMP-5 polypeptides and/or cells (e.g., stem cells) designed to express BMP-5 polypeptides can be administered to (e.g., injected into) the rotator cuff region of a mammal suffering from a rotator cuff condition. In such cases, the administered (e.g., injected) composition can reduce or reverse tendon degeneration, enhance healing, and/or increase tendon strength. Any appropriate rotator cuff condition can be treated as described herein. For example, rotator cuff tendonitis or rotator cuff injuries such as partial rotator cuff tears or rotator cuff ruptures can be treated as described herein. In addition, any appropriate mammal can be treated as described herein. For example, humans, monkeys, dogs, horses, sheep, pigs, goats, rabbits, rats or mice can be treated as described herein.

In some cases, a composition that includes BMP-5 polypeptides can be used to treat rotator cuff conditions. An example of a BMP-5 polypeptide that can be used as described herein includes, without limitation, a human BMP-5 polypeptide having the amino acid sequence set forth in SEQ ID NO: 1. As described herein, a composition that includes a human BMP-5 polypeptide can be administered to a human having a rotator cuff condition under conditions wherein the composition reduces or reverses tendon degeneration, enhances healing, and/or increases tendon strength.

In some cases, a composition that includes one or more inhibitors of SIRT6, SIRT7, and/or HDACIO polypeptide expression or activity can be used to treat rotator cuff conditions. Examples of inhibitors of SIRT6 polypeptide expression or activity include, without limitation, anti-SIRT6 antibodies, siRNA molecules against SIRT6, microRNAs targeting SIRT6, and constructs designed to edit genomic DNA to reduce expression of SIRT6 (e.g., CRISPR based strategies). Additional examples of inhibitors of SIRT6 polypeptide expression or activity include, without limitation, those inhibitors described elsewhere (see, e.g., Parenti et ah, J. Med. Chem.,

57(l l):4796-804 (2014) and He e? a/., Org. Biomol Chem., 12(38):7498-502 (2014)). In some cases, an inhibitor of SIRT6 polypeptide activity can have the following structure:

In some cases, commercial kits can be used to identify SIRT6 inhibitors. For example, the SIRT6 Inhibitor Screening Kit available from BioVision Inc. (Cat. No. K323-100) can be used to identify SIRT6 inhibitors.

Examples of inhibitors of SIRT7 polypeptide expression or activity include, without limitation, anti-SIRT7 antibodies, siRNA molecules against SIRT7, microRNAs targeting SIRT7, and constructs designed to edit genomic DNA to reduce expression of SIRT7 (e.g., CRISPR based strategies).

Examples of inhibitors of HDACIO polypeptide expression or activity include, without limitation, anti-HDACIO antibodies, siRNA molecules against HDACIO, microRNAs targeting HDACIO, constructs designed to edit genomic DNA to reduce expression of HDACIO (e.g., CRISPR based strategies), CUDC-907, pracinostat (also known as SB939; (E)-3-(2-Butyl-l-(2-(diethylamino)ethyl)-lH-benzo[d]imidazol -5- yl)-N-hydroxyacrylamide), abexinostat (also known as PCI-24781; 3- [(Dimethylamino)methyl]-N- {2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-l- benzofuran-2-carboxamide), quisinostat (N-Hydroxy-2-[4-( { [( 1 -methyl- 1 H-indol-3 - yl)methyl]amino}methyl)-l-piperidinyl]-5-pyrimidinecarboxami de), pracinostat (SB939), CUDC-101, CUDC-907, PCI-34051, and N-hydroxy-4-(2-((2- hydroxyethyl)(phenyl)amino)-2-oxoethyl)benzamide (CAS 1429651 -50-2).

As described herein, a composition that includes one or more inhibitors of SIRT6, SIRT7, and/or HDAC10 polypeptide expression or activity can be administered to a human having a rotator cuff condition under conditions wherein the composition reduces or reverses tendon degeneration, enhances healing, and/or increases tendon strength.

The term "antibody" as used herein refers to intact antibodies as well as antibody fragments that retain some ability to bind an epitope. Such fragments include, without limitation, Fab, F(ab')2, and Fv antibody fragments. The term

"epitope" refers to an antigenic determinant on an antigen to which the paratope of an antibody binds. Epitopic determinants usually consist of chemically active surface groupings of molecules (e.g., amino acid or sugar residues) and usually have specific three dimensional structural characteristics as well as specific charge characteristics.

The antibodies provided herein can be any antibody (e.g., a monoclonal antibody) having binding affinity (e.g., specific binding affinity) for a SIRT6, SIRT7, or HDAC10 polypeptide. For example, an anti-SIRT6 antibody preparation or an anti-SIRT7 antibody preparation provided herein can be a preparation of Fab fragments having the ability to bind to SIRT6 (e.g., human SIRT6) or SIRT7 (e.g., a human SIRT7). Any appropriate method can be used to produce Fab fragments from intact antibodies. For example, standard papain digestion methods can be used to make a Fab antibody preparation.

Antibodies provided herein can be prepared using any appropriate method. For example, a sample containing a human SIRT6 polypeptide can be used as an immunogen to elicit an immune response in an animal such that specific antibodies are produced. The immunogen used to immunize an animal can be chemically synthesized or derived from translated cDNA. In some cases, the immunogen can be conjugated to a carrier polypeptide, if desired. Commonly used carriers that are chemically coupled to an immunizing polypeptide include, without limitation, keyhole limpet hemocyanin (KLH), thyroglobulin, bovine serum albumin (BSA), and tetanus toxoid.

The preparation of polyclonal antibodies is well known to those skilled in the art. See, e.g., Green et ah, Production of Polyclonal Antisera, in

IMMUNOCHEMICAL PROTOCOLS (Manson, ed.), pages 1 5 (Humana Press 1992) and Coligan et al, Production of Polyclonal Antisera in Rabbits, Rats, Mice and Hamsters, in CURRENT PROTOCOLS IN IMMUNOLOGY, section 2.4.1 (1992). In addition, those of skill in the art will know of various techniques common in the immunology arts for purification and concentration of polyclonal antibodies, as well as monoclonal antibodies (Coligan, et al, Unit 9, Current Protocols in Immunology, Wiley Interscience, 1994).

The preparation of monoclonal antibodies also is well known to those skilled in the art. See, e.g., Kohler & Milstein, Nature 256:495 (1975); Coligan et al, sections 2.5.1 2.6.7; and Harlow et al, ANTIBODIES: A LABORATORY

MANUAL, page 726 (Cold Spring Harbor Pub. 1988). Briefly, monoclonal antibodies can be obtained by injecting mice with a composition comprising an antigen, verifying the presence of antibody production by analyzing a serum sample, removing the spleen to obtain B lymphocytes, fusing the B lymphocytes with myeloma cells to produce hybridomas, cloning the hybridomas, selecting positive clones that produce antibodies to the antigen, and isolating the antibodies from the hybridoma cultures. Monoclonal antibodies can be isolated and purified from hybridoma cultures by a variety of well-established techniques. Such isolation techniques include affinity chromatography with Protein A Sepharose, size exclusion chromatography, and ion exchange chromatography. See, e.g., Coligan et al, sections 2.7.1 2.7.12 and sections 2.9.1 2.9.3; Barnes et al, Purification of

Immunoglobulin G (IgG) , in METHODS IN MOLECULAR BIOLOGY, VOL. 10, pages 79 104 (Humana Press 1992).

In addition, methods of in vitro and in vivo multiplication of monoclonal antibodies are well known to those skilled in the art. Multiplication in vitro can be carried out in suitable culture media such as Dulbecco's Modified Eagle Medium or RPMI 1640 medium, optionally replenished by mammalian serum such as fetal calf serum, or trace elements and growth sustaining supplements such as normal mouse peritoneal exudate cells, spleen cells, and bone marrow macrophages. Production in vitro provides relatively pure antibody preparations and allows scale up to yield large amounts of the desired antibodies. Large scale hybridoma cultivation can be carried out by homogenous suspension culture in an airlift reactor, in a continuous stirrer reactor, or in immobilized or entrapped cell culture. Multiplication in vivo may be carried out by injecting cell clones into mammals histocompatible with the parent cells (e.g., osyngeneic mice) to cause growth of antibody producing tumors. Optionally, the animals are primed with a hydrocarbon, especially oils such as pristane (tetramethylpentadecane) prior to injection. After one to three weeks, the desired monoclonal antibody is recovered from the body fluid of the animal.

In some cases, the antibodies provided herein can be made using non-human primates. General techniques for raising therapeutically useful antibodies in baboons can be found, for example, in Goldenberg et al, International Patent Publication WO 91/1 1465 (1991) and Losman et al., Int. J. Cancer, 46:310 (1990).

In some cases, the antibodies can be humanized monoclonal antibodies.

Humanized monoclonal antibodies can be produced by transferring mouse complementarity determining regions (CDRs) from heavy and light variable chains of the mouse immunoglobulin into a human variable domain, and then substituting human residues in the framework regions of the murine counterparts. The use of antibody components derived from humanized monoclonal antibodies obviates potential problems associated with the immunogenicity of murine constant regions when treating humans. General techniques for cloning murine immunoglobulin variable domains are described, for example, by Orlandi et al., Proc. Nat'l. Acad. Set USA 86:3833 (1989). Techniques for producing humanized monoclonal antibodies are described, for example, by Jones et al., Nature 321 :522 (1986); Riechmann et al., Nature 332:323 (1988); Verhoeyen et al, Science 239: 1534 (1988); Carter et al, Proc. Nat'l. Acad. Sci. USA 89:4285 (1992); and Sandhu, Crit. Rev. Biotech. 12:437 (1992); Singer et al, J. Immunol. 150:2844 (1993). In some cases, humanization such as super humanization can be used as described elsewhere (Hwang et al, Methods, 36:35-42 (2005)). In some cases, SDR grafting (Kashmiri et al, Methods, 36:25-34 (2005)), human string content optimization (Lazar et al, Mol. Immunol, 44: 1986- 1998 (2007)), framework shuffling (Dall'Acqua et al, Methods, 36:43-60 (2005); and Damschroder et al, Mol. Immunol, 44:3049-3060 (2007)), and phage display approaches (Rosok et al, J. Biol. Chem., 271 :2261 1-22618 (1996); Radar et al, Proc. Natl Acad. Sci. USA, 95:8910-8915 (1998); and Huse et al, Science, 246: 1275-1281 (1989)) can be used to obtain anti-SIRT6, anti-SIRT7, or anti-HDACIO antibody preparations. In some cases, fully human antibodies can be generated from recombinant human antibody library screening techniques as described elsewhere (Griffiths et al, EMBO J., 13 :3245-3260 (1994); and Knappik et al, J. Mol. Biol, 296:57-86 (2000)). Antibodies provided herein can be derived from human antibody fragments isolated from a combinatorial immunoglobulin library. See, for example, Barbas et al, METHODS: A COMPANION TO METHODS IN ENZYMOLOGY, VOL. 2, page 119 (1991) and Winter et al, Ann. Rev. Immunol 12: 433 (1994). Cloning and expression vectors that are useful for producing a human immunoglobulin phage library can be obtained, for example, from STRATAGENE Cloning Systems (La Jolla, CA).

In addition, antibodies provided herein can be derived from a human monoclonal antibody. Such antibodies can be obtained from transgenic mice that have been "engineered" to produce specific human antibodies in response to antigenic challenge. In this technique, elements of the human heavy and light chain loci are introduced into strains of mice derived from embryonic stem cell lines that contain targeted disruptions of the endogenous heavy and light chain loci. The transgenic mice can synthesize human antibodies specific for human antigens and can be used to produce human antibody secreting hybridomas. Methods for obtaining human antibodies from transgenic mice are described by Green et al. (Nature Genet., 7: 13 (1994)), Lonberg et al (Nature, 368:856 (1994)), and Taylor et al (Int. Immunol, 6:579 (1994)).

Antibody fragments can be prepared by proteolytic hydrolysis of an intact antibody or by the expression of a nucleic acid encoding the fragment. Antibody fragments can be obtained by pepsin or papain digestion of intact antibodies by conventional methods. For example, Fab fragments can be produced by enzymatic cleavage of antibodies with papain. In some cases, antibody fragments can be produced by enzymatic cleavage of antibodies with pepsin to provide a 5S fragment denoted F(ab')2. This fragment can be further cleaved using a thiol reducing agent, and optionally a blocking group for the sulfhydryl groups resulting from cleavage of disulfide linkages, to produce 3.5S Fab' monovalent fragments. In some cases, an enzymatic cleavage using pepsin can be used to produce two monovalent Fab' fragments and an Fc fragment directly. These methods are described, for example, by Goldenberg (U.S. Patent Nos. 4,036,945 and 4,331,647). See also Nisonhoff et al, Arch. Biochem. Biophys. 89:230 (1960); Porter, Biochem. J. 73 : 119 (1959); Edelman et al, METHODS IN ENZYMOLOGY, VOL. 1, page 422 (Academic Press 1967); and Coligan ei a/. at sections 2.8.1 2.8.10 and 2.10.1 2.10.4.

Other methods of cleaving antibodies, such as separation of heavy chains to form monovalent light heavy chain fragments, further cleavage of fragments, or other enzymatic, chemical, or genetic techniques may also be used provided the fragments retain some ability to bind (e.g., selectively bind) its epitope.

The antibodies provided herein can be substantially pure. The term

"substantially pure" as used herein with reference to an antibody means the antibody is substantially free of other polypeptides, lipids, carbohydrates, and nucleic acid with which it is naturally associated. Thus, a substantially pure antibody is any antibody that is removed from its natural environment and is at least 60 percent pure. A substantially pure antibody can be at least about 65, 70, 75, 80, 85, 90, 95, or 99 percent pure.

In some cases, a composition that includes one or more inhibitors of a BMP-5 polypeptide inhibitor can be used to treat rotator cuff conditions. Examples of BMP-5 polypeptide inhibitors include, without limitation, a Noggin polypeptide, chordin, gremlin, glycosaminoglycans (GAGs), and GAG modifying enzymes. Examples of inhibitors of a BMP-5 polypeptide inhibitor include, without limitation, anti-Noggin, anti-chordin, and anti-gremlin antibodies, and siRNA molecules against Noggin, chordin, and gremlin. Administration of such inhibitors of a BMP-5 polypeptide inhibitor can reduce or block the activity of a BMP-5 polypeptide inhibitor to enhance BMP-5 signaling in injured or degenerative rotator cuff tendons.

In some cases, a composition that includes cells expressing a BMP-5 polypeptide can be used to treat rotator cuff conditions. For example, cells (e.g., stem cells) can be transfected to include exogenous nucleic acid (e.g., an expression vector) that encodes a BMP-5 polypeptide. In such cases, the cells can express the BMP-5 polypeptides. Examples of cells that can be designed to express BMP-5 polypeptides and used to treat rotator cuff conditions include, without limitation, stem cells (e.g., adipose derived stem cells, bone marrow derived stem cells, induced pluripotent stem cells, and primary mesenchymal cells), osteoblasts, and osteoblastic cells, cells within bone or bone fragments cultured ex vivo, and cell lines capable of producing recombinant polypeptides (e.g. CHO, COS, and Hela cells). In some cases, the cells can be cells obtained from the mammal (e.g., human) that is being treated. For example, stem cells can be obtained from a patient, designed to express human BMP- 5 polypeptides, and administered to that same patient. Examples of vectors that can be used to direct the expression of BMP-5 within cells include, without limitation, plasmids, synthetic mRNAs, and viral vectors (e.g., AAV, foamy virus, sendai virus, lentivirus, measles virus, or adenovirus vectors).

A composition provided herein (e.g., a composition containing a BMP-5 polypeptide or a cell designed to express a BMP-5 polypeptide) can be administered to a rotator cuff region of a mammal by intra-articular injection into the joint space, injection into the subacromial space, direct injection into damaged tendons, delivery as a topical at the time of surgical repair that could include delivery to the tendon itself, delivery to the bone tendon interface, or delivery directly into the joint space. In some cases, a composition provided herein (e.g., a composition containing a BMP- 5 polypeptide or a cell designed to express a BMP-5 polypeptide) can be administered to a rotator cuff region of a mammal using a suture placed into the joint, adjacent to the tendon, or at the bone tendon interface.

In some cases, a composition provided herein (e.g., a composition containing a BMP-5 polypeptide or a cell designed to express a BMP-5 polypeptide) can lack a tissue scaffold (e.g., a biodegradable nanofiber scaffold or a collagen scaffold). For example, a liquid composition without a tissue scaffold structure can be designed to include a BMP-5 polypeptide or a cell designed to express a BMP-5 polypeptide and can be administered to (e.g., injected into) a mammal to treat a rotator cuff condition.

In some cases, the methods and materials provided herein (e.g., a composition containing a BMP-5 polypeptide or a cell designed to express a BMP-5 polypeptide) can be used to treat tendonitis or a tendon disorder such as an Achilles tendon disorder, a patellar tendon disorder, a quadriceps tendon disorder, or an epicondylitis.

The invention will be further described in the following examples, which do not limit the scope of the invention described in the claims.

EXAMPLES

Example 1 - Assessment of damaged/ruptured rotator cuff tendons

High throughput RNA-sequencing of intact and ruptured rotator cuff tendons was performed. The sequencing analysis initially identified the BMP receptor, ACVR1C, as being highly up-regulated in intact tendons versus damaged/ruptured rotator cuff tendons (Table 1).

Table 1. Expression of BMP receptors in rotator cuff tendon. Gene Fold Change

Intact vs Diseased Tendon

ACVR1 3.06

ACVR1B 4.41

ACVRIC 52.41

ACVR2A 4.15

ACVR2B 2.27

ACVRL1 0.76

BMPR1A 3.48

BMPR1B 1.57

BMPR2 2.91

Once the ACVRIC receptor was identified, the ligands that bind to the ACVRIC receptor as well as downstream signaling molecules related to this receptor were evaluated. An evaluation of sequencing data revealed that BMP5 exhibited the greatest increase in expression amongst the possible ACVRIC receptor ligands, showing an 11.06 fold increase in intact rotator cuff tendon compared to diseased ruptured tendons (Table 2). A decrease in BMP signaling in damaged rotator cuff tendon also was confirmed by a reduction in the mRNA levels of the BMP specific SMAD proteins (SMADl, SMAD5, and SMAD9), which are normally activated by the binding of BMPs to the ACVR1 C receptor (Table 3).

Table 2. Expression of BMP in intact versus diseased rotator cuff tendon.

Table 3. Expression of SMAD polypeptides that are activated via downstream signaling through ACVRIC. Gene Fold Change Intact vs Diseased Tendon

SMAD1 6.17

SMAD2 2.04

SMAD3 2.26

SMAD4 1.92

SMAD5 3.25

SMAD6 2.89

SMAD7 2.92

SMAD9 4.11

BMP5 expression also was examined across various tissue types including bone, cartilage, muscle, tendon, and ligament. BMP5 exhibited the highest levels of expression in bone, but it showed the second highest levels of expression in tendon (Figure 1). These results suggest that BMP5 is involved in the maintenance of a normal tendon phenotype. These results also suggest that BMP5 polypeptides can be used therapeutically to treat degenerative rotator cuff disease, for example, as a prophylactic agent prior to rupture or as an adjunct to treat tendons that are undergoing repair (e.g., surgical repair).

RNA sequencing data also revealed a global down-regulation in gene expression in diseased rotator cuff tendon, which includes hundreds of regulatory transcription factors. SIRT6, SIRT7, HDAC10, RTNG1, and CARM1 are epigenetic regulators that promote gene silencing and were found to have elevated expression levels in degenerative tendon samples (Table 4).

Table 4. The expression of gene silencing epigenetic regulators in rotator cuff tendon.

These results suggest that SIRT6, SIRT7, HDAC10, RING1, and CARM1 are involved in the diseased rotator cuff tendon phenotype. These results also suggest that inhibitors of SIRT6, SIRT7, HDAC10, RTNGl, and CARM1 expression or activity can be used therapeutically to treat degenerative rotator cuff disease, for example, as a prophylactic agent prior to rupture or as an adjunct to treat tendons that are undergoing repair (e.g., surgical repair). Example 2 - Injecting BMP-5 polypeptides to treat

damaged/ruptured rotator cuff tendons

BMP-5 polypeptides are synthesized at GMP-grade facilities using eukaryotic cells lines (e.g., CHO cells, HeLa cells, or adipose derived mesenchymal stem cells) to produce BMP-5. The BMP-5 is purified from cell extracts. 0.5 to 10 mg of BMP-5 polypeptide is formulated with 1 to 10 mL of 4 mM HC1 or other soluble solution to obtain a liquid composition having a final concentration of about 0.5 to 5 mg/mL. This liquid composition is injected at a dose of 0.1 to 5 mg/mL directly into degenerative or surgically repaired tendons or into the joint space to deliver a total amount of BMP-5 in the range of 0.1 mg and 50 mg per administration.

Example 3 - Injecting cells designed to express BMP-5 polypeptides to treat damaged/ruptured rotator cuff tendons

A viral vector or other nucleic acid-based vector designed to express BMP-5 constitutively in a cell is introduced into stem cells or other somatic cell types. These modified cells are formulated with saline or other cell culture medium to obtain a liquid composition having a final concentration of about 100,000 to 20 x 10 ⁶ cells/mL. This liquid composition is injected at a dose of about 100,000 to 20 x 10 ⁶ cells/mL directly into a damaged tendon or a joint/subacromial space to deliver a total number of cells in the range of 100,000 and 20 x 10 ⁶ per administration. BMP-5 expressing stem cells are injected with or without ultrasound guidance. In some cases, these techniques can be used to treat degenerative tendons at risk for rupture or to augment surgical repair of previously ruptured tendons. OTHER EMBODIMENTS

It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.