Abstract
Background aims
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 α (MHC-α) 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-α 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.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (30370510, 30170337, 30400322, 30870851), CMB fund (4209347), Key Project of the State Ministry of Public Health (2001321), Fok Ying Tung Education Foundation (91029) and Key Projects in the National Science and Technology Pillar Program during the Eleventh Five-Year Plan Period (2006BAI05A07).
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.