Imatinib attenuates severe mouse dystrophy and inhibits proliferation and fibrosis-marker expression in muscle mesenchymal progenitors

Imatinib mesylate inhibits signaling of tyrosine kinase receptors, including PDGFRα, and has been used for human cancer therapy. Recent studies have indicated that imatinib is also effective in treatment of some chronic diseases with fibrosis. Fibrosis is the feature of Duchenne muscular dystrophy. It has been reported that imatinib attenuates fibrosis in mdx mice. Recently we revealed that PDGFRα is specifically expressed in muscle mesenchymal progenitors, which are the origin of muscle fibrosis. Here, we show that imatinib ameliorates the muscular pathology of DBA/2-mdx, a more severe mouse muscular dystrophy. In addition, imatinib inhibits both the proliferation and fibrosis marker expression induced by PDGF-AA in muscle mesenchymal progenitors in vitro. Importantly, the effective dose of imatinib on muscle mesenchymal progenitors did not inhibit myoblast proliferation. These results suggest that imatinib targets mesenchymal progenitors, and that a therapeutic strategy targeting mesenchymal progenitors could be a potential treatment for muscular dystrophies.