WO2007062000A2 - Fibroblast growth factor-5 and uses thereof - Google Patents

Abstract

The present invention provides methods of using a FGF5 polypeptide, a FGF5 polynucleotide, and a cell expressing a FGF5 polypeptide in stimulating formation of a skeletal muscle cell, stimulating formation, growth and survival of a skeletal muscle tissue in a subject. The present invention further provides methods of using a FGF5 polypeptide, a FGF5 polynucleotide, a cell expressing a FGF5 polypeptide in regenerating a skeletal muscle tissue, or treating a disorder or disease or injury of a skeletal muscle tissue in a subject.

Description

Fibroblast Growth Factor-5 and Uses Thereof

TECHNICALFIELD

This invention relates to the therapeutic uses of fibroblast growth factor 5 (FGF5).

BACKGROUND

Under normal circumstances, mammalian adult skeletal muscle is a stable tissue with very little turnover of nuclei. However, upon, injury, damage, or disease or disorder, skeletal muscle has the remarkable ability to initiate a rapid and extensive repair process preventing the loss of muscle mass. Skeletal muscle repair is a highly synchronized process involving the activation of various cellular responses. The initial phase of muscle repair is characterized by necrosis of the damaged tissue and activation of an inflammatory response. This phase is rapidly followed by activation of myogenic cells such as muscle precursor cells to proliferate, differentiate, and fuse leading to new myotube and myofiber formation, which consequently replace the damaged or injured muscle fibers.

Fibroblast growth factors have been shown to play important roles in muscle regeneration. They represent a set of secreted polypeptides that have known functions in developmental processes. See Bottcher & Niehrs (2005), Endocrine Rev. 26(1): 63-77.

SUMMARY

In one aspect, the present invention relates to a method of using FGF5 polypeptides for formation, growth and survival of skeletal muscle cells. In one embodiment, the method includes contacting skeletal muscle precursor cells with a FGF5 polypeptide described herein. The skeletal muscle precursor cells can be satellite cells, myoblasts, skeletal muscle stem cells or mononucleated cells.

In another aspect, the present invention relates to a method for treating a disorder or disease, injury of a skeletal muscle tissue, or regeneration of a skeletal muscle tissue in a subject, by administering to the subject an effective amount of a pharmaceutical i composition comprising a FGF5 polypeptide. In one embodiment, the method of the present invention includes systemic administration of the composition comprising the FGF5 polypeptide as described herein. In another embodiment, the method of the present invention includes local administration of the composition comprising the FGF5 polypeptide as described herein.

The pharmaceutical composition comprising the FGF5 polypeptide can be administered to the subject alone or in combination with one or more other therapeutic agents, preferably myogenic agents.

Another aspect of the present invention relates to gene therapy using the FGF5 polynucleotide. In one embodiment, the present invention relates to ex vivo gene therapy. The ex vivo gene therapy involves removing cells from the skeletal muscle tissues of a subject, genetically modifying the cells by introducing the FGF5 polynucleotide into the cells and culturing the cells in vitro, and subsequently transplanting the cells back into the same subject.

Alternatively, the cells can be removed from the skeletal muscle tissues of a subject, genetically modified with the FGF5 polynucleotide, cultured in vitro, then transplanted back into the a different subject of the same species.

In another embodiment, the present invention relates to in vivo gene therapy. Such method involves the direct administration of the FGF5 polynucleotide or a complex comprising the FGF5 polynucleotide into the skeletal muscle cells of the subject being treated.

BRIEF DESCRIPTION OF DRAWINGS

FIG. IA is a photograph of undifferentiated C2C12 myoblasts (top) and is a photograph of terminally differentiated C2C12 myotubes 5 days after induction (bottom).

FIG. IB is a line graph illustrating a myogenic gene expression profile in C2C12 myoblasts during differentiation. Known myogenic gene transcript regulation is shown as a function of time. Each data point is the average of 3 experiments. Differentiation was induced at day 0 by lowering the serum concentration from 10% to 3% v/v.

FIG. 2A is a line graph illustrating^/ gene expression in C2C12 cells during differentiation as derived from Affymetrix gene expression profile data.

FIG. 2B is a line graph illustrating bmp4 gene expression in C2C12 cells during differentiation of C2C12 cells as derived from Affymetrix gene expression profile data. t FIG. 3 A is a photograph illustrating differentiation of C2C12 cells in the absence of lμM

FGF5 for 3 days. Approximate percentage of myoblast conversion to myotubes in the culture is indicated.

FIG. 3B is a photograph illustrating differentiation of C2C12 cells in the presence of lμM FGF5 for 3 days. Approximate percentage of myoblast conversion to myotubes in the culture is indicated.

FIG. 3 C is a photograph illustrating differentiation of C2C12 cells in the presence of 1OnM bone morphogenic protein 4 (BMP4) for 3 days. Approximate percentage of myoblast conversion to myotubes in the culture is indicated.

FIG. 4 is a line graph illustrating PGC- lα promoter driven reporter gene activity through C2C12 differentiation. Luciferase reporter gene expression driven by the 2kb PGC-I α gene promoter was used as a surrogate marker to track mitochondrial biogenesis as a function of time. Differentiation of C2C12 cells was induced at day 0 and reporter gene activity was tracked for 5 days. Cells were cultured in the absence or presence of either 10 nM BMP4 or 1 μM FGF5.

DETAILED DESCRIPTION

Definitions

As used herein, the term "polynucleotide" refers to deoxyribonucleotides or ribonucleotides and polymers thereof in either single- or double-stranded form. The term encompasses nucleic acids containing known nucleotide analogs or modified backbone residues or linkages, which are synthetic, naturally occurring, and non-naturally occurring, which have similar binding properties as the reference nucleic acids, and which are metabolized in a manner similar to the reference nucleotides. Examples of such analogs include, without limitation, phosphorothioates, phosphoramidates, methyl phosphonates, chiral-methyl phosphonates, 2-0- methyl ribonucleotides, and peptide- nucleic acids (PNAs). A polynucleotide sequence also encompasses naturally-occurring allelic variants of said polynucleotide.

As used herein, the term "polypeptide" refers to a polymer in which the monomers are amino acids and are joined together through peptide or disulfide bonds. It also refers to either a full-length naturally-occurring amino acid sequence or a fragment thereof between about 8 and about 500 amino acids in length. Additionally, unnatural amino acids, for example, beta-alanine, phenyl glycine and homoarginine may be included. Commonly-encountered amino acids which are not gene-encoded may also be used in the present invention. All of the amino acids used in the present invention may be either the D- or L-optical isomer. The L-isomers are preferred. A polypeptide sequence also encompasses naturally-occurring allelic variants of said polypeptide.

As used herein, the term "an analog" in the context of a polypeptide of the present invention refers to a polypeptide that differs in amino acid sequences from the referenced polypeptide but retains similar or substantially the same biological function of the referenced polypeptide. Typically, polypeptide analogs comprise a conservative amino acid substitutions (or insertions or deletions) with respect to the referenced polypeptide sequence. A "conservative amino acid substitution" is one in which an amino acid residue is replaced with another residue having a chemically similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Alternatively, a polypeptide analog can comprise non-conservative amino acid substitutions where the analog retains similar or substantially the same biological function. The polypeptide analog also refers to a polypeptide where one or more amino acid residues are modified with chemical groups or are chemical mimetics of corresponding amino acid residues. Polypeptide mimetics are structurally similar to the referenced polypeptides, but have one or more peptide linkages optionally replaced by a linkage selected from the group consisting of: ~ CH₂NH-, — CH₂S-, -CH₂-CH₂-, -CH=CH- (cis and trans), ~ COCH₂-, -CH(OH)CH₂-, and ~ CH₂SO-.

As used herein, the term "a skeletal muscle cell" refers to a myotube or a muscle fiber.

As used herein, "a skeletal muscle precursor cell" refers to any cell that commits to the process of proliferation and differentiation into a skeletal muscle cell. Furthermore, the term "a skeletal muscle precursor cell" can be referred to as a myoblast or a satellite cell or a skeletal muscle stem cell or a mononucleated cell found in close contact with muscle fibers in skeletal muscle.

As used herein, the term "tissue" refers to a collection of similar cells and the intercellular substances surrounding them. One of ordinary skill in the art recognizes that a tissue is an aggregation of similarly specialized cells for the performance of a particular function. One of ordinary skill in the art further recognizes that there are four basic tissues in the body: 1) epithelium; 2) connective tissues, including blood, bone, and cartilage; 3) muscle tissue (smooth, cardiac and skeletal); and 4) nerve tissue. As used herein, the term "skeletal muscle tissue" is a contractile tissue comprised of skeletal muscle cells, dominated by skeletal muscle fibers and characterized as striated, voluntary muscle, having principally bony attachments. The "skeletal muscle tissue" is also called striated muscle tissue.

As used herein, the term "formation of a skeletal muscle cell" refers to production of a new skeletal muscle cell resulting from activation, proliferation or differentiation of a skeletal muscle precursor cell. In one embodiment, the term "formation of a skeletal muscle cell" refers to activation, proliferation of a satellite cell to yield a myoblast cell and/or differentiation and fusion of a myoblast to yield a myotube and/or muscle fiber.

As used herein, the term "formation of a skeletal muscle tissue" refers to production of a new skeletal muscle tissue as a result of formation of skeletal muscle cells.

As used herein, the term "growth of a skeletal muscle tissue" refers to an increase in the number of skeletal myotubes and skeletal muscle fibers. The term "growth of a skeletal muscle tissue" also refers to an increase in skeletal muscle fiber size or the number of fibers. The increase is preferably at least about 10%, about 25%, about 40%, about 50%, about 75%, about 100% or more. The growth of a skeletal muscle tissue can be measured by methods known in the art, such as but not limited to, measurement of: 1) an increase in wet weight of the skeletal muscle; 2) an increase in protein content; 3) an increase in the number of skeletal muscle fibers; or 4) an increase in skeletal muscle fiber diameter.

As used herein, the term "survival of a skeletal muscle tissue" refers to prevention of loss of the skeletal muscle fibers. The term also refers to a decrease in the rate of skeletal muscle cell death relative to an untreated control by at least about 10%, about 30%, about 50%, about 100%, about 200% or more.

As used herein, the term "injury of a skeletal muscle tissue" refers to a strained, torn or pulled skeletal muscle, as well as a skeletal muscle with a contusion (bruise), laceration, ischemia or rupture.

As used herein, the term "regenerating a skeletal muscle tissue" or "regeneration of a skeletal muscle tissue" refers to a process by which new muscle fibers form, reproduce or renew from skeletal muscle precursor cells, preferably from satellite cells or myoblast cells.

As used herein, the term "stimulating" or "stimulation" refers to activating or inducing. As used herein, the term "a myogenic agent" refers to an agent that stimulates activation, and/or proliferation, and/or differentiation of skeletal muscle precursor cells. Preferably the myogenic agent stimulates formation, growth and survival of skeletal muscle cells.

As used herein, the term "pharmaceutically acceptable carrier" includes any and all solvents, dispersion media, coatings, surfactants, antioxidants, preservatives (e.g., antibacterial agents, antifungal agents), isotonic agents, absorption delaying agents, salts, preservatives, drugs, drug stabilizers, binders, excipients, disintegration agents, lubricants, sweetening agents, flavoring agents, dyes, such like materials and combinations thereof, as would be known to one of ordinary skill in the art (see, for example, Remington's Pharmaceutical Sciences, 18th Ed. Mack Printing Company, 1990, pp. 1289- 1329, incorporated herein by reference). Except insofar as any conventional carrier is incompatible with the active ingredient, its use in the therapeutic or pharmaceutical compositions is contemplated.

The term "an effective amount or dose" of a compound of the present invention refers to an amount of the compound of the present invention that will elicit the biological or medical response of a subject, or ameliorate symptoms, slow or delay disease progression, or prevent a disease, etc. In a preferred embodiment, the "effective amount" refers to the amount that is sufficient to induce activation, proliferation, differentiation, growth or survival of a skeletal muscle cell.

As used herein, the term "subject" refers to an animal. Preferably, the animal is a mammal, either human or non-human. A subject also refers to for example, primates (e.g., humans), cows, pigs, sheep, goats, horses, dogs, cats, rabbits, rats, mice, fish, birds and the like. In a preferred embodiment, the subject is a human.

As used herein, the term "a disorder" or "a disease" refers to any derangement or abnormality of function; a morbid physical or mental state. See Dorland's Blustrated Medical Dictionary, (W.B. Saunders Co. 27th ed. 1988). As used herein, the term "treating" or "treatment" of any disease or disorder refers in one embodiment, to ameliorating the disease or disorder (i.e., arresting or reducing the development of the disease or at least one of the clinical symptoms thereof). In another embodiment "treating" or "treatment" refers to ameliorating at least one physical parameter, which may not be discernible by the patient. In yet another embodiment,

"treating" or "treatment" refers to modulating the disease or disorder, either physically, (e.g., stabilization of a discernible symptom), physiologically, (e.g., stabilization of a physical parameter), or both. In yet another embodiment, "treating" or "treatment" refers to preventing or delaying the onset or development or progression of the disease or disorder.

As used herein, the term "a," "an," "the" and similar terms used in the context of the present invention (especially in the context of the claims) are to be construed to cover both the singular and plural unless otherwise indicated herein or clearly contradicted by the context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

Method of stimulating formation of skeletal muscle cells

The present invention is based on the surprising discovery that FGF5 polypeptide stimulates or induces myoblasts to differentiate into skeletal myotubes. Accordingly, in one aspect, the present invention relates to a method of using FGF5 polypeptides for formation, growth and survival of skeletal cells. In one embodiment, the method includes contacting skeletal muscle precursor cells with a FGF5 polypeptide described herein. The skeletal muscle precursor cells can be satellite cells, myoblasts, skeletal muscle stem cells or mononucleated cells. The contact of the FGFG5 polypeptide with the skeletal muscle precursor cells can cause the skeletal muscle precursor cells to be activated, resulting in proliferation, differentiation and formation of new skeletal muscle cells such as myotubes and muscle fibers. The newly formed skeletal muscle cells promote survival of skeletal muscle tissues.

The method described herein employs a mammalian FGF5 polypeptide. The FGF5 polypeptide sequences from many mammalian species are well known in the art. An exemplary human FGF-5 polypeptide including all or a portion of the following sequence is shown below.

MSLSFLLLLFFSHLILSAWAHGEKRLAPKGQPGPAATDRNPRGSSSRQSSSSAMSS SSASSSPAASLGSQGSGLEQSSFQWSPSGRRTGSLYCRVGIGFHLQIYPDGKVNGS HEANMLSVLEIFAVSQGIVGIRGVFSNKFLAMSKKGKLHASAKFTDDCKFRERFQ ENSYNTYASAIHRTEKTGREWYVALNKRGKAKRGCSPRVKPQHISTHFLPRFKQ SEQPELSFTVTVPEKKKPPSPIKPKIPLSAPRKNTNSVKYRLKFRFG (SEQ ID NO:2).

The corresponding human FGF-5 polynucleotide sequence encoding for the above FGF5 polypeptide sequence are the following:

CCCAGAATCAGCCCTACAAGATGCACTTAGGACCCCCGCGGCTGGAAGAATG AGCTTGTCCTTCCTCCTCCTCCTCTTCTTCAGCCACCTGATCCTCAGCGCCTGG GCTCACGGGGAGAAGCGTCTCGCCCCCAAAGGGCAACCCGGACCCGCTGCCA CTGATAGGAACCCTAGAGGCTCCAGCAGCAGACAGAGCAGCAGTAGCGCTA TGTCTTCCTCTTCTGCCTCCTCCTCCCCCGCAGCTTCTCTGGGCAGCCAAGGA AGTGGCTTGGAGCAGAGCAGTTTCCAGTGGAGCCCCTCGGGGCGCCGGACCG GCAGCCTCTACTGCAGAGTGGGCATCGGTTTCCATCTGCAGATCTACCCGGAT GGCAAAGTCAATGGATCCCACGAAGCCAATATGTTAAGTGTTTTGGAAATAT TTGCTGTGTCTCAGGGGATTGTAGGAATACGAGGAGTTTTCAGCAACAAATTT TTAGCGATGTCAAAAAAAGGAAAACTCCATGCAAGTGCCAAGTTCACAGATG ACTGCAAGTTCAGGGAGCGTTTTCAAGAAAATAGCTATAATACCTATGCCTC AGCAATACATAGAACTGAAAAAACAGGGCGGGAGTGGTATGTGGCCCTGAA TAAAAGAGGAAAAGCCAAACGAGGGTGCAGCCCCCGGGTTAAACCCCAGCA TATCTCTACCCATTTTCTGCCAAGATTCAAGCAGTCGGAGCAGCCAGAACTTT CTTTCACGGTTACTGTTCCTGAAAAGAAAAAGCCACCTAGCCCTATCAAGCC AAAGATTCCCCTTTCTGCACCTCGGAAAAATACCAACTCAGTGAAATACAGA CTCAAGTTTCGCTTTGGATAATATTCCTCTTGGCCTTGTGAGAAACC (SEQ ID NO:1; for RNA, all "T's" are replaced with "U's").

Although the above-described polypeptide and nucleic acid are particularly useful in the present invention, one of ordinary skill in the art will recognize that numerous . analogs or fragments of the sequences are also useful in the methods of the present invention. Accordingly, analogs or fragments of the FGF5 polypeptides exhibiting similar or substantially the same biological activity are also encompassed by the present invention. One of ordinary skill in the art also recognizes that FGF-5 polypeptides and nucleic acids obtained from other animal species e.g., rodent, primate, canine, feline, etc., can be used in the described method as well, provided that they are, or that they encode, polypeptides with similar or substantially the same biological function as the human FGF5 polypeptide.

A variety of methods known in the art can be utilized to prepare the FGF5 polypeptides of the present invention.

Pharmaceutical compositions and routes of administration

The FGF5 polypeptides of the present invention can be administered to skeletal muscle precursor cells as pharmaceutical compositions. Therefore, another aspect of the present invention relates to a pharmaceutical composition comprising a FGF5 polypeptide and a pharmaceutically acceptable carrier. The characteristics of the pharmaceutical carrier depend on the route of administration, which can be any suitable route, locally or systemically. Suitable routes of administration can, for example, include oral, rectal, transmucosal, or intestinal administration; parenteral delivery, including intramuscular, subcutaneous, intramedullary injections, as well as intrathecal, direct intraventricular, intravenous, intraperitoneal, intranasal, or intraocular injections. Administration of polypeptides of the present invention used in the pharmaceutical compositions or to practice the method of the present invention can be carried out in a variety of conventional ways, such as oral ingestion, inhalation, topical application or cutaneous, subcutaneous, intraperitoneal, parenteral or intravenous injection. Intravenous administration to the patient is preferred.

In one embodiment, the pharmaceutical compositions of the present invention are systemically administered to the muscle tissue in need of muscle regeneration. Systemic administration of a FGF5 polypeptide or other therapeutic composition according to the invention can be performed by methods of whole-body drug delivery are well known in the art. These include, but are not limited to, intravenous drip or injection, subcutaneous, intramuscular, intraperitoneal, intracranial and spinal injection, ingestion via the oral route, inhalation, trans-epithelial diffusion (such as via a drug-impregnated, adhesive patch).

In another embodiment, the pharmaceutical compositions of the present invention are administered locally to the target muscle cell or tissue, or the vicinity of the target muscle cell or tissue. This can be achieved by, for example, and not by way of limitation, local infusion during surgery, topical application, e.g., in conjunction with a wound dressing after surgery, by injection, by means of a catheter, by means of a suppository, or by means of an implant, said implant being of a porous, non-porous, or gelatinous material, including membranes, such as sialastic membranes, or fibers. Furthermore, the pharmaceutical compositions of the present invention are administered in a targeted drug delivery system, for example, in a liposome coated with a specific antibody, targeting for example, and skeletal muscle tissue.

Typically, the route of administration depends on the type of formulation being used and the indication treated. The determination of a suitable route of administration and an effective dosage for a particular indication is within the level of skill in the art. For inducing skeletal muscle production or treatment of conditions responsive to the skeletal muscle regeneration, any suitable route of administration described herein will apply. Preferably, routes of administration include, for example, injection or implantation of the pharmaceutical compositions directly to the site in need of production of new muscle cells (muscle regeneration), oral administration, topical administration and liposome.

The pharmaceutical compositions suitable for injection can be formulated in the form of a pyrogen-free, parenterally acceptable aqueous solution. The preparation of such formulation has due regard to pH, isotonicity, stability, and the like, is within the skill in the art. A preferred pharmaceutical composition injection should contain, in addition to protein or other active ingredient of the present invention, an isotonic vehicle such as Sodium Chloride Injection, Ringer's Injection, Dextrose Injection, Dextrose and Sodium Chloride Injection, Lactated Ringer's Injection, or other vehicle as known in the art. The pharmaceutical composition of the present invention can also contain stabilizers, preservatives, buffers, antioxidants, or other additives known to those of skill in the art for injection, the polypeptides of the invention can be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks's solution, Ringer's solution, or physiological saline buffer.

The pharmaceutical compositions suitable for implantation can formulated as a depot preparation, or a sustained release formulation or an injectable formulation described above. The implantable pharmaceutical compositions can be shaped as desired in anticipation of surgery or shaped by the physician or technician during surgery. Preferably, the shape spans a tissue defect and takes the desired form of the new tissue. Moreover, the implantable pharmaceutical composition can be partially enclosed in a supporting physical structure such as a mesh, wire matrix, microparticles or microspheres that are placed in contact or in close vicinity to the skeletal muscle site in need of muscle formation, growth or regeneration.

The pharmaceutical compositions for oral administration can be formulated by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient to be treated. Pharmaceutical preparations for oral use can be obtained from a solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores. Suitable excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP). If desired, disintegrating agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate. Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs. or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.

The pharmaceutical composition for topical administration can be formulated in liquid or semi-liquid preparations suitable for penetration through the skin, and drops suitable for administration to the eye, ear, or nose. The formulation includes but is not limited to, liquid or semi-liquid preparations such as liniments, lotions, oil-in-water or water-in-oil emulsions such as creams, ointments or pastes, and solutions or suspensions. Topically- administrable formulations may, for example, comprise from about 1% to about 10% (w/w) active ingredient, although the concentration of the active ingredient may be as high as the solubility limit of the active ingredient in the solvent.

Treatment of muscle-related conditions

The pharmaceutical compositions of the present invention are particular useful for treatment of conditions in which muscle regeneration is specifically frustrated.

Therefore, another aspect of the present invention relates to a method for treating a disorder or disease, injury of a skeletal muscle tissue, or regeneration of a skeletal muscle tissue in a subject, by administering to the subject an effective amount of a pharmaceutical composition comprising a FGF5 polypeptide. In one embodiment, the method of the present invention includes systemic administration of the composition comprising the FGF5 polypeptide as described herein. In another embodiment, the method of the present invention includes local administration of the composition comprising the FGF5 polypeptide as described herein.

The skeletal muscle disorder, disease, or injury includes, but is not limited to, myopathies, dystrophies, cachexia, sarcopenia, myoneural conductive diseases, muscle injury and results of nerve injury, disuse atrophy, and age-related muscle atrophy.

Alternatively, the pharmaceutical compositions and methods of the present invention can be used to increase muscle mass in normal muscle tissues, e.g., during aging and athletic activity in subjects, either humans or non-human mammals (such as hourse and dog, etc). For example, the present invention contemplates increasing muscle mass in subjects (e.g., humans, horses or dogs) for enhancement of athletic abilities and to increase the protein yield from farm animals (e.g., pigs, cows and chickens).

Individuals considered at risk for muscle disorders or diseases may benefit particularly from the invention, primarily because the treatment can begin before there is any evidence of the disorder. Individuals "at risk" include, e.g., subjects infected with HIV, those who have sustained trauma to the muscle tissues, those diagnosed with but not yet displaying symptoms of muscular dystrophy, those suffering from loss of appetite or cachexia, those who are bedridden for long periods, those undergoing chemotherapy and those who become paralyzed, e.g., due to car or other accident, among many others.

In conjugation with the treatments of the present invention, other approaches can be employed in the treatment of muscle-related disorder, diseases, or injuries. The approaches include, but are not limited to, administration of anti-inflammatory agents, pain killers, steroids, hypertrophy-inducing hormones, physical therapy, therapeutic ultrasound, hyperbaric oxygen, and surgical intervention.

The pharmaceutical compositions of the present invention include compositions wherein the active ingredients are contained in an effective amount or dose to achieve its intended purposes. One of ordinary skill in the art can determine the appropriate dose and frequency of administration(s) to achieve an optimum clinical result. The dose of the FGF5 polypeptides for the use of the present invention depends on a variety of factors, including the size of the muscle, the severity of the muscle disorder or disease or injury. An exemplary dose can range from about 0.01 μg/kg to about 200mg/kg of body weight daily, preferably about 0.1 μg/kg to about 50 mg/kg of body weight daily. The dose can be once daily, or equivalent doses can be delivered at longer or shorter intervals.

The pharmaceutical compositions comprising the FGF5 polypeptide can be administered to the subject alone or in combination with one or more other therapeutic agents ("combinations of FGF5"). Preferably the agents are myogenic agents that would facilitate or stimulate formation, growth, survival or regeneration of a skeletal muscle cell or tissue. Non-limiting examples of such agents include fibroblast growth factor 1, fibroblast growth factor 2, insulin-like growth factors I and II, hepatocyte growth factor and myostatin inhibitors. These factors are involved in nearly all stages of muscle regeneration, they promote satellite cell activation and proliferation, as well as differentiation of myoblast into muscle tubes and fibers

Furthermore, the combinations of FGF 5 can be administered to a subject via simultaneous, separate or sequential administration. Simultaneous administration can take place in the form of one fixed combination of the FGF5 polypeptide with one or more other agents, or by simultaneously administering the FGF5 polypeptide and one or more other agents that are formulated independently. Sequential administration preferably means administration of the FGF polypeptide in a combination at one time point, other agents at a different time point, that is, in a chronically staggered manner, preferably such that the combination shows more efficiency than the single compounds administered independently (especially showing synergism). Separate administration preferably means administration of the FGF 5 polypeptide and other agents in the combinations independently of each other at different time points.

Also combinations of FGF 5 of sequential, separate and simultaneous administrations are possible, preferably such that the combination agents show a joint therapeutic effect that exceeds the effect found when the combination agents are used independently at time intervals so large that no mutual effect on their therapeutic efficiency can be found, a synergistic effect being especially preferred.

Gene Therapy

The FGF5 polynucleotides of the present invention can be used for gene therapy. Such polynucleotides can be introduced either ex vivo or in vivo into cells for expression in a subject.

In one embodiment, the present invention relates to ex vivo gene therapy. The ex vivo gene therapy involves removing cells from the skeletal muscle tissues of a subject, genetically modifying by introducing the FGF5 polynucleotide into the cells and culturing the cells in vitro, and subsequently transplanting the cells back into the same subject. Alternatively, the cells can be removed from the skeletal muscle tissues of a subject, genetically modified with the FGF5 polynucleotide, cultured in vitro, then transplanted back into the a different subject of the same species.

In another embodiment, the present invention relates to in vivo gene therapy. Such method involves the direct administration of the FGF5 polynucleotide or a complex comprising the FGF5 polynucleotide into the skeletal muscle cells of the subject being treated. In in vivo gene therapy, the cells are not removed from the subject.

The polynucleotides of the present invention are in a suitable form for expression in the cells of a subject. Accordingly, the polynucleotides can include coding and regulatory sequences required for transcription of a gene (or portion thereof) and translation of the polypeptide encoded by the gene. Regulatory sequences which can be included in the polynucleotide include promoters, enhancers and polyadenylation signals, as well as sequences necessary for transport of an encoded polypeptide, for example N- terminal signal sequences for transport of polypeptides to the surface of the cell or for secretion.

Nucleotide sequences which regulate expression of a gene (e.g., promoter and enhancer sequences) are selected based upon the type of cell in which the gene product is to be expressed and the desired level of expression of the gene product. For example, a promoter known to confer cell-type specific expression of a gene linked to the promoter can be used. A promoter specific for myoblast gene expression can be linked to a gene of interest to confer muscle-specific expression of that gene product. Muscle-specific regulatory elements which are known in the art include upstream regions from the dystrophin gene (Klamut et al., (1989) MoI. Cell. Biol. 9:2396), the creatine kinase gene (Buskin and Hauschka, (1989) MoI. Cell Biol. 9:2627) and the troponin gene (Mar and Ordahl, (1988) Proc. Natl. Acad. ScL USA. 85:6404). Regulatory elements specific for other cell types are known in the art (e.g., the albumin enhancer for liver-specific expression; insulin regulatory elements for pancreatic islet cell-specific expression; various neural cell-specific regulatory elements, including neural dystrophin, neural enolase and A4 amyloid promoters). Alternatively, a regulatory element which can direct constitutive expression of a gene in a variety of different cell types, such as a viral regulatory element, can be used. Examples of viral promoters commonly used to drive gene expression include those derived from polyoma virus, Adenovirus 2, cytomegalovirus and Simian Virus 40, and retroviral LTRs. Alternatively, a regulatory element which provides inducible expression of a gene linked thereto can be used. The use of an inducible regulatory element (e.g., an inducible promoter) allows for modulation of the production of the gene product in the cell. Examples of potentially useful inducible regulatory systems for use in eukaryotic cells include hormone-regulated elements (e.g., see Mader, S. and White, J. H. (1993) Proc. Natl. Acad. Sci. USA

90:5603-5607), synthetic ligand-regulated elements (see, e.g. Spencer, D. M. et al. (1993) Science 262:1019-1024) and ionizing radiation-regulated elements (e.g., see Manome, Y. et al. (1993) Biochemistry 32:10607-10613; Datta, R. et al. (1992) Proc. Natl. Acad. ScL USA 89: 10149-10153). Additional tissue-specific or inducible regulatory systems which may be developed can also be used in accordance with the invention.

There are a number of techniques known in the art for introducing genetic material into a cell that can be applied to modify a cell of the invention. In one embodiment, the polynucleotide is in the form of a naked nucleic acid molecule. In this situation, the nucleic acid molecule introduced into a cell to be modified consists only of the polynucleotide encoding the gene product and the necessary regulatory elements. Alternatively, the nucleic acid (including the necessary regulatory elements) is contained within a plasmid vector that is well known in the art. In another embodiment, the nucleic acid molecule to be introduced into a cell is contained within a viral vector such as, by way of non-limiting examples, a retroviral vector, an adenovirus vector and adeno- associated virus (AAV). Yet in another embodiment, the nucleic acid molecule to be introduced into the cells is in the form of microparticle bombardment such as gene gun, or coating with lipids or cell-surface receptors or transfecting agents, or in linkage to a homeobox-like peptide which is known to enter the nucleus (See Joliot et al., Proc. Natl. Acad. Sd. USA 88:1864-1868(1991)). Alternative, the nucleic acid can be introduced and incorporated into the host cell DNA for expression by homologous recombination.

Vector DNA or nucleic acids described herein can be introduced into host cells using conventional transformation or transfection techniques. As used herein, the terms "transformation" and "transfection" are intended to refer to a variety of art-recognized techniques for introducing foreign nucleic acid (e.g., DNA) into a host cell, including calcium phosphate or calcium chloride co-precipitation, DEAE-dextran-mediated transfection, lipofection, "naked" DNA, viral infection, "gene gun" or electroporation. Suitable methods for transforming or transfecting host cells can be found in Sambrook et al. {supra) and other laboratory manuals.

EXAMPLES

Example 1. FGF-5 augments differentiation of C2C12 myoblasts

Cell culture and differentiation

C2C12 mouse skeletal myoblasts were cultured in DMEM high glucose (Gibco) with 10% FBS (Gibco) and 1% penicillin/streptomycin (Gibco). Cells were maintained at 37°C and 5% CO₂. To differentiate C2C12 myoblasts into myotubes, the serum concentration was reduced to 2-3% and maintained in culture for up to 5 days with media changes every 2 days. Gene expression profiling

C2C12 cell RNA was harvested using the RNeasy Midiprep kit (Qiagen) following the manufacturer's instructions. Cells were cultured in 6-well plates and a time-course of differentiation was performed. Induction of differentiation was initiated at time 0, when the C2C12 cells were confluent, by reducing the serum concentration in the wells to 3% v/v. Cells were lysed for RNA preparation at days -1, 0, 0.25, 1, 2, 3, 4 and 5 post differentiation. RNA was analyzed using the Affymetrix mouse whole genome microarray, MOE430 PLUS 2.0.

Reporter gene assay

Undifferentiated C2C12 cells were harvested from 75mm flasks to 100mm plates

(Falcon), and immediately transfected while still in suspension. For transient transfection, 25μl of Fugene, along with 800μl Optimem, 5μg reporter gene plasmid, and 0.5μg renilla luciferase reporter gene plasmid were prepared as recommended by the manufacturer. Culture plates were incubated overnight at 37⁰C to allow efficient transfection. Cells were trypsinized, harvested, and split into 24-well or 96-well plates, and calculated for immediate confluency upon adherence of the cells. Differentiation media containing 2% serum was added to the cells either simultaneously with plating, or after the cells were seeded and grown for a night in regular growth media. In the latter case, the regular growth media was exchanged for differentiation media the following morning. After 48 hours incubation, cells were harvested in lysis buffer and frozen at - 80⁰C until needed for analysis. The luciferase assay was performed in accordance with the manufacturers' (Promega) instructions. Luminescence was determined using a luminescence plate reader with dual-injection capability (Perkin Elmer). Data was analyzed using Microsoft Excel, and figures were generated using Graphpad Prism4 software. Results

C2C12 cell differentiation and gene expression profiling

To identify potential regulatory genes of myogenic differentiation, we profiled the gene expression pattern of the entire mouse genome during differentiation of C2C12 myoblasts to skeletal myotubes. A time-course experiment was carried out in which cells undergoing differentiation were isolated, mRNA harvested, and expression profiles generated by microarray analysis between the stages of myoblast proliferation, through confluency, cell-cycle arrest, cell fusion and terminal differentiation. Figure 1 (panel A) shows photographs of C2C12 cells whilst proliferating as mononucleate cells (top panel), and as terminally differentiated myotubes (bottom panel). Using Affymetrix microarray chips, we generated expression data from which we analyzed the variation in specific gene expression as a function of time. Panel B shows myogenic gene transcript regulation as a function of time, during the differentiation of C2C12 myoblasts. Each data point is the average of 3 experiments. Differentiation was induced at day 0 by lowering the serum concentration from 10% to 3% v/v. As expected, a chosen set of myogenic genes that included myogenin, creatine kinase, cyclin Dl and nicotinic receptor, all responded consistently with C2C12 differentiation (Figure 1, panel B)

Fibroblast growth factor gene expression

Figure 2 shows a time-course of A) various fgf genes and B) bmp4 gene expression during differentiation of C2C12 cells, as derived from Affymetrix gene expression profile data. Of the 23 FGFs that have been identified to date, we found that four were significantly regulated during the differentiation process. Three of these genes, FGF7, FGF 13 and FGF21, were upregulated over the time-course, whereas FGF5 was repressed (Figure 2, panel A). This profile interested us because we assumed that the data was likely an underestimation of the actual profile, as not all of the C2C12 cells were differentiated to myotubes. Thus it was highly likely that those cells that remained mononucleate myoblasts were expressing higher levels of FGF5, such that the overall expression level in the culture was falsely elevated. We also speculated that FGF5 may in fact stimulate, or permit myogenesis, such that when cells reached the myotube phenotype, a feedback mechanism to reduce incessant differentiation may ensue. We derived this hypothesis from our own data, as we noticed that the myogenic inhibitory factor BMP4 was significantly upregulated through C2C12 differentiation (Figure 2, panel B). Thus, within the enclosed culture system of the experiment it appeared that a feedback mechanism may emerge as a significant factor in cell state regulation.

Effect of exogenous FGF5 on C2C12 differentiation

Figure 3 shows differentiation of C2C12 cells in the absence (A) or presence of lμM FGF5 (B) or 1OnM BMP4 (C) for 3 days. Approximate percentage of myoblast conversion to myotubes in the culture was assessed by visual analysis and is indicated as an approximate value. To test whether FGF5 had a direct functional effect on differentiation of C2C12 cells, we induced differentiation in the presence or absence of exogenous FGF5. After 3 days, the degree of differentiation in the FGF5-treated cells was significantly augmented, compared with the control cells (Figure 3, panels A-B). We quantitated that approximately 75% of the myoblasts had formed myotubes in the presence of FGF5, whereas only 35% of cells were differentiated under control conditions. As a further control, we treated myoblasts with BMP4 protein during induction of differentiation (Figure 3, panel C). As expected, BMP4 blocked differentiation, and moreover, prevented cell-cycle arrest such that the density of mononucleate C2C12 cells was clearly increased. From these data, we suggest that BMP4 prevents myogenic differentiation of C2C12 cells, whereas FGF5 augments differentiation compared with the untreated control.

Effect of exogenous FGF5 on PGC-I a promoter-driven reporter gene activity

As a surrogate biomarker of mitochondrial biogenesis, we used a PGC- lα promoter driven reporter gene assay. The results are shown in Figure 4. Luciferase reporter gene expression driven by the 2kb PGC- lα gene promoter was used as a surrogate marker to track mitochondrial biogenesis as a function of time. Differentiation of C2C12 cells was induced at day 0 and reporter gene activity was tracked for 5 days. Cells were treated in the absence or presence of either 10 nM BMP4 or 1 μM FGF5.

Data represents mean values of reporter gene expression +/- standard deviation (n = 6). Mitochondrial biogenesis is a necessary step in the differentiation process of myoblasts, as additional energy is required for the physical process of fusion to form myotubes. After 5 days of C2C12 differentiation, PGC- lα reporter gene expression was increased approximately 12 fold over day 0 (Figure 4). In the presence of BMP4, which is known to block differentiation but not proliferation, the PGC- lα reporter gene activity was maintained at basal level. In the presence of exogenous FGF5, reporter gene activity was augmented beyond that of the control by approximately 2-fold at 5 days post differentiation induction, such that levels reached approximately 24-fold above basal level. Though not direct evidence, these data suggest that mitochondrial biogenesis is augmented as a function of FGF 5 treatment during myogenic differentiation, and support the data in Figure 3 showing that FGF5 enhances myogenic differentiation.

The data presented here suggest that FGF5 functions directly on myoblasts to augment their differentiation potential toward skeletal myotubes, and also supports the hypothesis that FGF5 plays a mechanistic role in myogenesis and/or muscle regeneration. Firstly, FGF5 gene expression was down-regulated as cells reached terminal differentiation. This was determined by gene expression analysis and was likely an underestimation of the shift in gene expression level. Secondly, exogenous FGF5 treatment clearly augmented myotube formation of C2C12 cells following induction of differentiation by serum deprivation. Thirdly, PGC- lα gene promoter activity was significantly enhanced when C2C12 cells were differentiated in the presence of FGF5. Collectively, these data argue that FGF5 plays a functional role in the myogenic process.

These studies pave the way for further investigations into the functional role of FGF5 in myogenesis and skeletal muscle regeneration. Such studies should include FGF5's impact on mesenchymal stem cell commitment to the myogenic lineage. Relevance to the mesenchymal switch from adipose to muscle is an underlying mechanism that may be further clarified with such studies. Potential therapeutic impact should also be investigated by testing the effects of exogenous FGF5 in the context of various muscular disease states, including muscular dystrophy, sarcopenia, cachexia, disuse atrophy and diabetes. Efforts to identify the signaling pathways by which FGF5 signals in muscle cells will provide important insight to myogenic commitment and may also present novel target discovery opportunities within this field of research.

References

Bottcher RT, Niehrs C (2005) Fibroblast growth factor signaling during early vertebrate development. Endocr Rev. 26(1): 63-77.

Clase KL, Mitchell PJ, Ward PJ, et al. (2000) FGF5 stimulates expansion of connective tissue fibroblasts and inhibits skeletal muscle development in the limb. Dev Dyn;2l9:368- 380.

Kastner S, Elias MC, Rivera AJ, et al. (2000) Gene expression patterns of the fibroblast growth factors and their receptors during myogenesis of rat satellite cells. J Histochem Cytochem;48:l079-I096.

Parker MH, Seale P, Rudnicki MA (2003) Looking back to the embryo: defining transcriptional networks in adult myogenesis. Nat Rev Genet;4:497-507.

Zhou P, Hoffman EP (2004) Embryonic myogenesis pathways in muscle regeneration. Dev Dyn;229:3S0-92.

Yamaguchi A, Ishii H, Morita I, et al. (2004) mRNA expression of fibroblast growth factors and hepatocyte growth factor in rat plantaris muscle following denervation and compensatory overload. Pflugers Arch; 448:539-546.

Other Embodiments

Other embodiments will be evident to those of skill in the art. It should be understood that the foregoing detailed description is provided for clarity only and is merely exemplary. The spirit and scope of the present invention are not limited to the above examples, but are encompassed by the following claims.

Claims

The Claims:

1 A method for stimulating formation of a skeletal muscle cell, comprising contacting the muscle cell with a FGF5 polypeptide.

2 A method for stimulating formation, growth and survival of a skeletal muscle tissue in a subject comprising administering to said subject an effective amount of a pharmaceutical composition comprising a FGF5 polypeptide.

3 A method for regenerating a skeletal muscle tissue in a subject comprising administering to said subject an effective amount of pharmaceutical composition comprising a FGF5 polypeptide.

4 A method of treating a disorder or disease or injury of a skeletal muscle tissue in a subject comprising administering to said subject an effective amount of a pharmaceutical composition comprising a FGF5 polypeptide.

5 The method of claim 4, the disorder or disease is one selected from myopathies, dystrophies, cachexia, sarcopenia, myoneural conductive diseases, muscle injury and results of nerve injury.

6 A method for regenerating a skeletal muscle tissue in a subject comprising administering to said subject an effective amount of a pharmaceutical composition comprising a FGF5 polypeptide in combination with a myogenic agent.

7 The method of claim 6, the myogenic agent is selected from fibroblast growth factor 1, fibroblast growth factor 2, insulin-like growth factors I arid II and hepatocyte growth factor.

8 A method for treating a disorder or disease or injury of a skeletal muscle tissue in a subject comprising administering to said subject an effective amount of a pharmaceutical composition comprising a FGF5 polypeptide in combination with a myogenic agent. The method of claim 8, the myogenic agent is selected from fibroblast growth factor 1, fibroblast growth factor 2, insulin-like growth factors I and II and hepatocyte growth factor.

A method for regenerating a skeletal muscle tissue in a subject comprising locally administering to the muscle tissue or the vicinity of the muscle tissue an effective amount of a pharmaceutical composition comprising a FGF5 polynucleotide or polypeptide.

A method for treating a disorder or disease or injury of a skeletal muscle tissue in a subject comprising locally administering to the muscle tissue or the vicinity of the muscle tissue an effective amount of a pharmaceutical composition comprising a

FGF5 polynucleotide or polypeptide.

A method for regenerating a skeletal muscle tissue in a subject comprising locally administering to the muscle tissue or the vicinity of the muscle tissue a muscle cell expressing and secreting a FGF5 polypeptide.

A method for treating a disorder or disease or injury of a skeletal muscle tissue in a subject comprising locally administering to the muscle tissue or the vicinity of the muscle tissue one or more skeletal muscle cells expressing and secreting a FGF5 polypeptide.

Use of a FGF5 polypeptide for the preparation of medicaments for stimulating formation of a skeletal muscle cell.

Use of a FGF5 polypeptide for the preparation of medicaments for stimulating formation, growth and survival of a skeletal muscle tissue in a subject.

Use of a FGF5 polypeptide for the preparation of medicaments for treating a disorder or disease or injury of a skeletal muscle tissue in a subject.