Skeletal muscle stem cells (MuSCs) have been proposed as suitable candidates for cell therapy in muscular disorders since they exhibit good capacity for myogenic regeneration. However, for better therapeutic outcomes, it is necessary to isolate human MuSCs from a suitable tissue source with high myogenic differentiation. In this context, we isolated CD56+CD82+ cells from the extra eyelid tissue of young and aged patients, and tested in vitro myogenic differentiation potential. In the current study, myogenic cells derived from extra eyelid tissue were characterized and compared with immortalized human myogenic cells. We found that myogenic cells derived from extra eyelid tissue proliferated and differentiated myofibers in vitro, and restored DYSTROPHIN or PAX7 expression after transplantation with these cells in mice with Duchenne muscular dystrophy. Thus, human myogenic cells derived from extra eyelid tissue including the orbicularis oculi might be good candidates for stem cell-based therapies for treating muscular diseases.

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Cell therapy is one of desired method for treating intractable muscular diseases, such as Duchenne muscular dystrophy (DMD). Here, we demonstrated the effective stepwise differentiation method from human iPSCs to engraftable muscle stem cells without transgene induction. We induced myotome-like population that is identified as Myf5 positive cells, which showed highly myogenic differentiation potential in vitro. Gene expression profile of purified Myf5+ cells demonstrated that the expression of Pax7 was significantly increased in Myf5+ cells at the late stage of differentiation. To assess the regeneration potential, we transplanted the Myf5+ cells at the late stage of differentiation into immunodeficient DMD-model mice. The Myf5+ cells could be engrafted in more than one hundred of host myofibers and regenerate the diseased muscles with producing dystrophin. Finally, we confirmed the recovery of muscle function after transplantation. Taken together, we demonstrate that the transplantation of the human iPSC-derived muscle stem cells with step-wise differentiation can be effective for DMD with amelioration of muscle function.