Inhibition of myostatin promotes myogenic differentiation of rat bone marrow-derived mesenchymal stromal cells.
OBJECTIVE
Mesenchymal stromal cells (MSC) have been thought to be attractive candidates for the treatment of Duchenne muscular dystrophy (DMD), but the rate of MSC myogenesis is very low. Thus MSC treatment for DMD is restricted. Myostatin (Mstn), a negative regulator of myogenesis, is known to be responsible for limiting skeletal muscle regeneration. We hypothesized that inhibition of Mstn by using anti-Mstn antibody (Ab) would ameliorate the myogenic differentiation of MSC in vitro and in vivo.


METHODS
MSC were isolated from rat bone marrow. Induced rat MSC (rMSC) were treated with various concentrations of anti-Mstn Ab. The expression of myogenic differentiation antigen (MyoD), myogenin and myosin heavy chain-type alpha (MHC-alpha) were estimated by immunofluorescence analysis and reverse transcription-polymerase chain reaction (RT-PCR). Adipogenic differentiation of rMSC inhibited by anti-Mstn Ab was evaluated by Oil Red O staining. The expression of dystrophin was detected 16 weeks after anti-Mstn Ab injection and rMSC transplantation by immunofluorescence staining, RT-PCR and Western blot. Motor function, serum creatine kinase (CK) and histologic changes were also evaluated.


RESULTS
Five-azacytidine-mediated myogenic differentiation induced significant endogenous Mstn expression. Anti-Mstn Ab improved the expression of MyoD, myogenin and MHC-alpha and inhibited adipocyte formation. Sixteen weeks after transplantation, the inhibition of Mstn had improved motor function and muscle mass. In accordance with the increased motor function and muscle mass, dystrophin expression had increased. Furthermore, serum CK and centrally nucleated fiber (CNF) levels decreased slightly, suggesting specific pathologic features of the dystrophic muscle were partially restored.


CONCLUSIONS
Using anti-Mstn Ab, we found that inhibition of Mstn improved myogenic differentiation of rMSC in vitro and in vivo. A combination of Mstn blockade and MSC transplantation may provide a pharmacologic and cell-based strategy for the treatment of DMD.
Geng
Jia
J
Neurology Department, The First Affiliated Hospital, Sun Yat-Sen University, Guang Zhou, PR China.
Peng
Funing
F
Xiong
Fu
F
Shang
Yanchang
Y
Zhao
Cuiping
C
Li
Wanyi
W
Zhang
Cheng
C
D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D000943:Antigens, Differentiation / Q000378:metabolism; D001374:Azacitidine / Q000008:administration & dosage; D001853:Bone Marrow / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D009043:Motor Activity; D024510:Muscle Development; D020388:Muscular Dystrophy, Duchenne / Q000139:chemically induced / Q000473:pathology / Q000628:therapy*; D055435:Myostatin / Q000037:antagonists & inhibitors / Q000276:immunology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017154:Stromal Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
D019138:Antibodies, Blocking; D000943:Antigens, Differentiation; D055435:Myostatin; D001374:Azacitidine