Effect and application of RNA binding protein in skeletal muscle injury repair

Abstract

The invention discloses an effect and application of RNA (Ribonucleic Acid) binding protein in skeletal muscle injury repair, and relates to the technical field of new application of medicines. A large number of experiments show that the RNA binding protein ARPP21 is up-regulated in the repair process after skeletal muscle injury. After the ARPP21 is knocked out, the repair capability of the mouse after skeletal muscle injury is weakened, and myoblast differentiation is inhibited. And when the ARPP21 is over-expressed, early migration of mouse myoblast differentiation can be promoted. Therefore, the ARPP21 plays an important regulating role in regeneration and repair after the skeletal muscle injury, can be used for preparing a medicine for regeneration and repair after the skeletal muscle injury, and provides a new clue and strategy for rehabilitation treatment after the skeletal muscle injury.

Description

Technical Field

[0001] The present invention relates to the technical field of new drug applications, and in particular to the role and application of an RNA binding protein in the repair of skeletal muscle damage. Background Art

[0002] Regeneration and repair of skeletal muscle after injury is one of the important issues that need to be overcome in the field of regenerative medicine. Skeletal muscle is the largest tissue in the human body, accounting for about 40% of the total body weight. It plays a vital role in all aspects of human life, such as adjusting posture, autonomous movement, breathing and metabolism. Maintaining healthy muscles is the main determinant of maintaining quality of life. Therefore, when skeletal muscle regeneration and repair disorders occur, muscle fiber degeneration will seriously impair body function, have a serious impact on mobility, independence and quality of life, and cause a huge socioeconomic burden. There is still a lack of effective treatment strategies.

[0003] The repair process of skeletal muscle after injury depends on the highly coordinated expression of many genes. RNA binding proteins (RBPs) are key determinants of gene expression, and they bind to RNA through one or more RNA binding domains. RBPs can interact with both coding RNA and non-coding RNA. Since many RNA molecules have similarities, most RBPs can bind to more than one RNA and participate in the regulation of multiple processes. However, only a small number of RBPs have been elucidated for their key functions in different aspects of skeletal muscle. Therefore, further understanding of the role of specific RBPs in skeletal muscle will not only help to understand the regulatory mechanism of gene expression during skeletal muscle injury and repair, but also help to understand the etiology and pathology of skeletal muscle diseases, and provide new treatment methods for the rehabilitation of skeletal muscle diseases. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a function and application of an RNA binding protein in the repair of skeletal muscle damage.

[0005] To achieve the above object, the technical solution adopted by the present invention is: use of RNA binding protein in the preparation of a drug for promoting regeneration and repair of skeletal muscle after injury.

[0006] The present invention also provides the use of RNA binding protein in the preparation of drugs for preventing or treating weakened skeletal muscle regeneration ability, skeletal muscle damage or atrophy caused by skeletal muscle related diseases.

[0007] The present invention also provides the use of RNA binding protein in preparing medicine for promoting myoblast differentiation or migration.

[0008] As a preferred embodiment of the application of the present invention, the RNA binding protein is ARPP21.

[0009] Skeletal muscle-related diseases and related defects in muscle regeneration and repair after injury or atrophy are a major public health issue in the global aging population structure, and there is a lack of truly effective prevention and treatment strategies at this stage. In-depth research on the molecular regulatory mechanisms of skeletal muscle differentiation and repair after injury is the basis for the development of treatment methods for skeletal muscle repair after injury, and is of great significance to human life. Epigenetic regulation has always been an important issue to pursue and explore in the field of RNA research. The present invention uses the RNA binding protein ARPP21 as an entry point and finds that ARPP21 is significantly upregulated in the early collagen deposition stage of skeletal muscle repair after injury, suggesting that ARPP21 is involved in the process of skeletal muscle repair after injury. Further determination of the molecular mechanism of ARPP21 regulating RNA networks will help to more fully understand the molecular mechanism of RBP's involvement in skeletal muscle differentiation and repair after injury.

[0010] As a preferred embodiment of the application of the present invention, the drug promotes the regeneration and repair of skeletal muscle after injury by promoting the growth of skeletal muscle.

[0011] As a preferred embodiment of the application of the present invention, the drug promotes the regeneration and repair of skeletal muscle after injury by promoting myoblast differentiation.

[0012] As a preferred embodiment of the application of the present invention, the drug promotes the regeneration and repair of skeletal muscle after injury by improving the migration ability of myoblasts.

[0013] As a preferred embodiment of the application of the present invention, the skeletal muscle-related diseases include torticollis and sarcopenia.

[0014] The present invention also provides a pharmaceutical composition for promoting regeneration and repair of skeletal muscle after injury, wherein the pharmaceutical composition comprises ARPP21 or a substance capable of increasing the expression level of ARPP21.

[0015] As a preferred embodiment of the pharmaceutical composition of the present invention, the pharmaceutical composition further comprises pharmaceutically acceptable excipients and / or auxiliary active ingredients.

[0016] Beneficial effects of the present invention: The present invention has found through a large number of experiments that the RNA binding protein ARPP21 is upregulated during the repair process of skeletal muscle injury. After knocking out ARPP21, it was found that the repair ability of mouse skeletal muscle injury was weakened and myoblast differentiation was inhibited. When ARPP21 is overexpressed, it can promote the early migration of mouse myoblast differentiation. Therefore, ARPP21 plays an important regulatory role in the regeneration and repair of skeletal muscle injury, and can be used to prepare drugs for the regeneration and repair of skeletal muscle injury, providing new clues and strategies for rehabilitation treatment after skeletal muscle injury. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1Figure 3 shows the changes in the expression level of ARPP21 during the skeletal muscle injury and repair process in mice. A shows the construction of the mouse skeletal muscle injury and repair model and the sampling time points; B shows the fibrosis process verified by MASSON staining during the skeletal muscle injury and repair process in mice; C shows the expression changes of ARPP21 at the protein level during the skeletal muscle injury and repair process in mice; D shows the expression changes of ARPP21 during the skeletal muscle injury and repair process in mice by IHC analysis.

[0018] Figure 2 The effects of ARPP21 deficiency on skeletal muscle development in mice, where A is the construction of skeletal muscle-specific ARPP21 knockout mice; B. shows the body shape changes of ARPP21-KO and ARPP21-WT mice at 6 weeks of age; C is HE staining showing the changes in mouse muscle fibers caused by ARPP21 knockout; D is immunofluorescence showing the changes in the cross-section of mouse muscle fibers caused by ARPP21 knockout; E is immunofluorescence showing the changes in the longitudinal section of mouse muscle fibers caused by ARPP21 knockout.

[0019] Figure 3 The effect of ARPP21 deficiency on the repair ability of skeletal muscle after injury in mice, where A constructs the skeletal muscle repair model after injury in ARPP21-KO and ARPP21-WT mice; B. HE staining shows the effect of ARPP21 knockout on the repair ability of skeletal muscle after injury in mice.

[0020] Figure 4 Figure 3 shows the effect of knocking down ARPP21 on the differentiation of mouse myoblasts, where A is the protein level verification of the ARPP21 knockdown stable strain; B is the effect of knocking down ARPP21 on the expression level of the skeletal muscle differentiation marker MHC protein; C is the effect of knocking down ARPP21 on the myofilament morphology after myoblast differentiation.

[0021] Figure 5 The effect of overexpression of ARPP21 on the migration of mouse myoblasts, wherein A is the protein level verification of overexpression of ARPP21; B is the Transwell verification of the effect of overexpression of ARPP21 on cell migration ability. DETAILED DESCRIPTION

[0022] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention.

[0023] The experimental method involved in the embodiment of the present invention is as follows:

[0024] Masson staining:

[0025] (1) Dewaxing of paraffin sections: First, soak the paraffin sections in xylene for 10 minutes, then soak them in anhydrous ethanol for 5 minutes, 95% ethanol for 5 minutes, 70% ethanol for 5 minutes, and distilled water for 5 minutes to remove the wax;

[0026] (2) chromization or mercury removal salt precipitation (this step can be omitted for formaldehyde-fixed tissues);

[0027] (3) staining cell nuclei with Weigert's iron hematoxylin stain or Regaud's hematoxylin stain for 5 to 10 minutes;

[0028] (4) Wash thoroughly. If the stain is excessive, use hydrochloric acid and alcohol to differentiate for a few seconds, then rinse with water;

[0029] (5) staining with Ponceau acid fuchsin solution for 5 to 10 minutes;

[0030] (6) treating with a 1% aqueous solution of phosphomolybdic acid for about 3 to 5 minutes;

[0031] (7) Without washing, stain directly with aniline blue or light green solution for 5 minutes;

[0032] (8) Treat with 0.2% glacial acetic acid aqueous solution for 1 minute;

[0033] (9) Place in 95% alcohol, anhydrous ethanol, and xylene in turn to make it transparent, and seal with neutral gum.

[0034] After completing the above steps, Masson-stained sections can be obtained, with different areas appearing pink or blue, cell nuclei appearing blue-black, muscle fibers, cellulose and red blood cells appearing red, and collagen fibers, mucus and cartilage appearing blue.

[0035] ICH (Immunohistochemistry):

[0036] (1) Embedding tissue: After fixing the tissue in 4% paraformaldehyde solution for 48 hours, place it in a disposable tissue embedding box for dehydration, and then embed it after wax immersion.

[0037] (2) Trimming: Trim the paraffin sections until most of the tissue is on the cut surface.

[0038] (3) Histochemistry: a. Wax block preparation: Soak the tissue wax block in an ice-water mixture in advance to soften it, place the tissue wax block on a microtome to cut 5-micron slices, and bake the slices at 60°C for 1 hour; b. Dewaxing: Place the slices in a 60°C oven and bake for more than 4 hours. Place the slices in xylene I for 0.5 hours, and then place them in xylene II for another 0.5 hours. c. Hydration: Soak the slices in alcohol. The alcohol concentrations are different, including 70%, 80%, 90%, 95%, and 100%. The soaking time for each concentration is also different. The first three concentrations are soaked for 2 minutes each, and the next two concentrations are soaked for 5 minutes and 10 minutes respectively. Finally, soak the slices in double distilled water for 2 minutes. d. Histochemistry: 1) Blocking treatment: Select an endogenous peroxidase blocker and the treatment time is 20 minutes. 2) Soak in double distilled water three times, each time for 5 minutes. 3) Antigen repair: Prepare 400-600ml of 10nM citric acid antigen repair solution with pH=6.0, put the slide in it, and seal the beaker mouth with plastic wrap to prevent boiling and overflow. Then put it in the microwave and heat it on high heat for 10 minutes. 4) After heating, fill the liquid level with double distilled water, heat in the microwave for 40 minutes (between medium and low heat and thawing), and fill the liquid level with double distilled water every 10 minutes. 5) After the repair is completed, put it at room temperature and let it cool naturally. 6) After washing with DDW for 180°C, wash with PBS for 3 minutes each time, for three times. 7) Block with primary antibody, maintain at 4°C, raise the temperature to 37°C on the next day, and then wash with PBS for 5 minutes. 8) Add reaction enhancement solution, then incubate at room temperature for 20 minutes, and then wash with PBS for 3 minutes each time, for three times. 9) Add enhancement enzyme-labeled goat anti-mouse / rabbit IgG polymer, then incubate at room temperature for 20 minutes, and then wash with PBS for 3 minutes each time, for three times. 10) Add DAB colorimetric solution (prepared immediately before use, ratio 1:19), incubate at room temperature for 2-10 minutes (choose the staining time according to different antibodies). Rinse gently with tap water. 11) Counterstaining: Add hematoxylin for 50 seconds. Use DDW, 3 minutes, PBS, 5 minutes × 3 times. 12) Dehydration: Soak the slides in different concentrations of alcohol gradients in turn: 70%, 1 minute-80%, 1 minute-90%, 1 minute-95% I, 5 minutes-95% II, 5 minutes-100% I, 5 minutes-100% II, 5 minutes. 13) Transparent: Use xylene I and xylene II for treatment, and each treatment lasts for 20 minutes. 14) Seal the slide with neutral resin, neutral resin, cover the slide with a glass (do not leave small bubbles in the tissue area), and dry naturally.

[0039] HE staining:

[0040] (1) Use xylene to remove the wax on the slices, and then wash them with ethanol (including anhydrous ethanol, 95% ethanol, 85% ethanol, 75% ethanol, and 65% ethanol) in stages.

[0041] (2) Place the dewaxed sections in a hematoxylin stain for 2 to 10 minutes. After staining, rinse with distilled water to remove excess dye.

[0042] (3) Place the sections in acid alcohol or acid solution for pickling to remove excess hematoxylin dye. The pickling time and the choice of pickling solution can be adjusted according to experimental needs.

[0043] (4) Place the sections in a blueing agent (such as acid alcohol or acid agarose) to enhance the hematoxylin staining effect. The treatment time is usually 1 to 5 minutes.

[0044] (5) Place the sections in an eosin dye solution for staining, usually for 1 to 5 minutes. After staining, rinse the sections thoroughly with distilled water to remove excess dye.

[0045] (6) The sections are dehydrated in an ethanol concentration gradient, immersed in a clearing agent to make them transparent, and finally mounted.

[0046] (7) Use appropriate sealing agents (such as sub-thermogel or acrylamide) to seal the slices.

[0047] Transwell assay to verify cell invasion ability:

[0048] (1) Dilute the matrix gel at a ratio of about 1:8 using serum-free medium on ice, add 100 μL / well to the upper chamber, cover the bottom of the chamber, and incubate in a cell culture incubator for 1-4 hours;

[0049] (2) Gently aspirate the excess matrix gel in the upper chamber, add 200 μL of cell suspension resuspended in serum-free medium, and add 500 μL of complete medium to the lower chamber. Be careful not to create bubbles when returning the cells to the chamber. Return the transwell plate to the incubator and continue culturing for 24-48 h.

[0050] (3) discard the culture medium in the upper and lower chambers, wash the upper and lower chambers three times each with PBS, and wipe away the uninvaded cells in the upper chamber with a cotton swab;

[0051] (4) Add 500 μL of paraformaldehyde to the lower chamber, place it in the chamber for fixation for 30 min, discard the paraformaldehyde, and dry the chamber;

[0052] (5) Add 500 μL of crystal violet solution to the lower chamber and place the chamber in the staining chamber for 30 minutes. Discard the crystal violet solution, use PBS to clean the staining solution, dry the chamber, and then observe under the microscope and take pictures;

[0053] (6) Five fields of view were randomly selected from each chamber for photographing. The number of invasive cells was counted using software or manually, and the average value of the five fields of view was calculated.

[0054] Example 1 Changes in the expression level of ARPP21 during the repair of mouse skeletal muscle injury

[0055] The specific experimental method is as follows: 25 μL of 10 μM cardiotoxin (CTX) was injected into the tibialis anterior (TA) muscle of 6-week-old male mice to establish a skeletal muscle injury and repair model, and 0.9% saline was injected as a control. The TA muscles of mice were collected 1, 3, 5, and 10 days after the injection of CTX to induce muscle fiber injury. Figure 1 A), and performed MASSON staining, IHC analysis, and detection of the protein expression level of ARPP21.

[0056] The results are as follows Figure 1 As shown by Figure 1 B shows a representative early inflammatory phase during mouse skeletal muscle repair, characterized by a transient increase in collagen deposition, followed by a resolution phase of healing and gradual restoration of normal tissue morphology. Figure 1 As shown in C and D, the expression level of ARPP21 is significantly upregulated in the collagen deposition stage during the repair of mouse skeletal muscle, and slowly downregulated in the late stage of skeletal muscle repair. The above results indicate that ARPP21 is activated and gradually upregulated during the repair process of skeletal muscle after injury.

[0057] Example 2 Effect of ARPP21 deficiency on skeletal muscle development in mice

[0058] The specific experimental method is as follows: mice carrying the ARPP21fl / fl allele (purchased from Cyagen) were crossed with HSA-CreER transgenic mice (purchased from Cyagen) to generate skeletal muscle-specific ARPP21 knockout (ARPP21-KO) mice. ARPP21-KO mice and control group offspring were named ARPP21-KO and ARPP21-WT, respectively. ARPP21-KO mice and control group offspring were injected with corn oil or tamoxifen every day for one week ( Figure 2 A), and recorded the changes in the body shape of the mice, used HE staining to detect the changes in the mouse muscle fibers, and used immunofluorescence to detect the changes in the cross-section and longitudinal sections of the mouse muscle fibers.

[0059] The results are as follows Figure 2 As shown by Figure 2B and C show that 7 days after tamoxifen injection, ARPP21-KO mice became smaller at 6 weeks of age; HE staining showed that the muscle fibers of ARPP21-KO mice were smaller and arranged more loosely, the muscles were poorly developed, the intercellular spaces were larger, and the interstitial proliferation ( Figure 2 D) Figure 2 E shows that the cross-sectional area of ​​ARPP21-KO mice is reduced compared with wild-type mice, and longitudinal sections show that the average diameter of ARPP21-KO mice is reduced compared with wild-type mice. These results indicate that ARPP21 is essential for skeletal muscle growth.

[0060] Example 3 Effect of ARPP21 deficiency on the repair ability of skeletal muscle after injury

[0061] The specific experimental method is as follows: ARPP21-KO and ARPP21-WT mice were injected with CTX to establish a skeletal muscle injury and repair model. TA muscles of healthy adult mice were collected 1, 3, 5, and 10 days after CTX injection to induce muscle fiber damage ( Figure 3 A), and HE staining was performed to detect the effect of ARPP21 knockout on the repair ability of mouse skeletal muscle after injury.

[0062] The results are as follows Figure 3 As shown, HE staining showed that at the late stage of skeletal muscle injury and repair, compared with ARPP21-WT, the muscle fibers of ARPP21-KO mice were smaller and more loosely arranged, and the nuclei were located in the middle of the muscle cells ( Figure 3 B). The above results indicate that ARPP21 deficiency impairs the repair ability of skeletal muscle after injury.

[0063] Example 4 Effect of knockdown of ARPP21 on mouse myoblast differentiation

[0064] The process of skeletal muscle regeneration and repair is a regeneration process dominated by terminal differentiation and growth. Mouse C2C12 cells are myogenic cells with differentiation ability obtained from the skeletal muscle of muscular dystrophy mice and are currently the most widely used cell line for studying skeletal muscle differentiation. In order to explore the function of ARPP21 in this process, an ARPP21 knockdown C2C12 stable strain ( Figure 4 A) The specific method is as follows: (1) One day in advance, C2C12 cells were plated in a 6-well plate with a cell number of 2.5 x 10 5 / well, the culture medium volume is 2300uL; (2) The next day, take 5uL of 20μM siRNA stock solution and add it to 83uL of serum-free culture medium (usually OPTI-MEM culture medium). When 5uL of siRNA is added to one well of a 6-well plate, the final concentration in the well is 50nM. Then add 12uL of HiPerFect transfection reagent to the above mixture and mix well. The total volume is 100uL at this time; (3) Incubate at room temperature for 5 to 10 minutes; (4) Add the above transfection complex dropwise to the 6-well plate and mix gently. Detect the expression level of the myoblast differentiation marker MHC in the above mouse C2C12 cells.

[0065] The results are as follows Figure 4 As shown in Figure 2, knockdown of ARPP21 significantly inhibited the expression level of myoblast differentiation marker MHC ( Figure 4 B), while immunofluorescence showed that knocking down ARPP21 also reduced the ability of myoblasts to differentiate and fuse to form myofilaments ( Figure 4 C).

[0066] Example 5 Effect of overexpression of ARPP21 on early migration of mouse myoblasts

[0067] The effect of overexpression of ARPP21 on early migration of mouse myoblast differentiation was explored by constructing ARPP21 overexpression myoblasts. The method for constructing ARPP21 overexpression myoblasts is as follows: (1) Gene construction: 1) Primers were designed according to the target gene mRNA coding region, and restriction sites EcoRI and Bgl II were added to both ends of the primers; 2) The target gene mRNA was extracted from the cells, and then reverse transcribed into cDNA, and then the CDS region of the target gene was amplified from the cDNA using primers. The target gene coding region sequence with restriction sites was amplified by PCR, connected to the pMD19-T vector, and then transformed into competent bacteria DH5α, and colony PCR identification and restriction digestion identification were performed respectively; 3) The target gene sequence was double-digested with EcoRI and Bgl II, recovered and purified by electrophoresis, and connected to the pMSCV-eGFP vector. Transform into competent bacteria DH5α again, and after successful colony PCR identification and enzyme digestion identification, send to the company for sequencing and identification; 4) After successful identification, transform the plasmid into competent bacteria DH5α, and extract the endotoxin-free plasmid. GAG plasmid and VSV plasmid can also be transformed into competent bacteria DH5α, and extract the endotoxin-free plasmid. After plasmid extraction, freeze and store at -20℃. (2) Lentivirus packaging: 1) Use DMEM complete medium to culture 6cm dish HEK293T to a confluence of 70-80%. Use opti-MEM and Lipo3000 to transfect pMSCV-eGFP, VSV, GAG plasmids containing the target gene and control vector respectively, and add liposome-plasmid transfection suspension to each dish and quantify according to the relevant instructions for purchasing liposomes. Continue to culture for 24 hours; 2) After 24 hours, replace the culture medium with fresh DMEM complete culture medium and continue to culture in a cell culture incubator for 48 to 72 hours; 3) After 48 to 72 hours, collect the upper culture medium and filter it through a 0.45μm filter membrane. Use ELISA to determine the viral titer of the obtained lentiviral vector. If not used in time, it can be frozen at -80℃. (3) Lentivirus transfection: 1) One day before transfection, inoculate the cells in a 6-well culture plate. The cell fusion rate during infection is about 50%. Before infection, change the medium and add 1mL DMEM complete culture medium. 2) After the virus melts in an ice bath, add the corresponding volume of virus solution and polybrene, mix well, and continue to culture in a 37℃ incubator. 3) After 4 hours, add 1mL of culture medium and change the medium after 14 hours (change the medium within 24 hours). 4) Observe the fluorescence under an inverted microscope 72 hours after virus infection to monitor the infection efficiency. When more fluorescence appears, add equal concentrations of Puromycin to equal amounts of transfected cells and untransfected cells (the screening concentration of Puromycin or other antibiotics needs to be explored in advance); 5) When all untransfected cells are dead and satisfactory fluorescence can be observed, reduce the Puromycin concentration for culturing.Monoclonal cell lines can also be selected for further culture to obtain satisfactory cell lines that stably express the target gene; 6) Use qRT-PCR and Western blot methods to detect whether the expression and protein levels of the target gene are significantly increased; 7) Three groups of cell lines can be obtained: a. Normal cell lines; b. Cell lines infected with empty viral vectors; c. Cells infected with viral vectors that overexpress the target gene; 8) When the stable cell lines are subsequently cultured and subcultured, low concentrations of Puromycin need to be added to the culture medium as a pressure screening condition. The ARPP21 protein level of the above-mentioned ARPP21 overexpressing myoblasts was detected, and the invasive ability of the above-mentioned ARPP21 overexpressing myoblasts was verified by Transwell assay.

[0068] The results are as follows Figure 5 As shown. Figure 5 A shows that the ARPP21 overexpressing myoblasts constructed above overexpress ARPP21 protein. Figure 5 B shows that overexpression of ARPP21 before myoblast differentiation significantly promotes myoblast migration ability, and cell migration is an essential step in the cell fusion process.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. Application of RNA binding proteins in the preparation of drugs for promoting regeneration and repair of skeletal muscle after injury.

2. The use of RNA binding proteins in the preparation of drugs for preventing or treating weakened skeletal muscle regeneration ability, skeletal muscle damage or atrophy caused by skeletal muscle related diseases.

3. Application of RNA binding protein in the preparation of drugs for promoting myoblast differentiation or migration.

4. The use according to any one of claims 1 to 3, characterized in that: The RNA binding protein is ARPP21.

5. The use according to claim 1, characterized in that: The drug promotes the regeneration and repair of skeletal muscle after injury by promoting the growth of skeletal muscle.

6. The use according to claim 1, characterized in that: The drug promotes the regeneration and repair of skeletal muscle after injury by promoting the differentiation of myoblasts.

7. The use according to claim 1, characterized in that: The drug promotes the regeneration and repair of skeletal muscle after injury by improving the migration ability of myoblasts.

8. The use according to claim 2, characterized in that: The skeletal muscle related diseases include torticollis and sarcopenia.

9. A pharmaceutical composition for promoting regeneration and repair of skeletal muscle after injury, characterized in that: The pharmaceutical composition comprises ARPP21 or a substance capable of increasing the expression level of ARPP21.

10. The pharmaceutical composition according to claim 9, characterized in that The pharmaceutical composition also includes pharmaceutically acceptable excipients and / or auxiliary active ingredients.

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