Sonic Hedgehog Supplementation Rapidly induces Myogenesis in Human Induced Pluripotent Stem Cells

We have reported that mouse embryonic stem (ES) cells transfected with insulin-like growth factor (IGF) II differentiated into mature skeletal muscle cells in vitro and in vivo after transplantation. On the contrary, IGFII transfected human induced pluripotent stem (hiPS) cells did not demonstrate mature skeletal muscle differentiation. The morphogenic factor Sonic Hedgehog (SHH) was suggested to upregulate the myogenic process along with IGF through Phosphoinositide 3 kinase (PI3K)/Akt signaling pathway. We cultured hiPS cells with SHH to generate myoblasts and transplanted the cells to hind limbs of mice.SHH with IGFII supplementation rapidly enhanced myogenic gene and protein expressions (MyoD, myogenin, Mrf4, and dystrophin) of hiPS cells. After the transplantation, we observed severe inflammation in the transplanted sites with host immunocompetent cells despite systemic administration of dexamethasone and cyclosporine. Surviving transplanted myoblasts showed lower expressions of myogenic proteins (MyoD, myogenin, and dystrophin) than in vitro cultured myoblasts did.We successfully generated mature skeletal muscle cells from hiPS cells with SHH supplementation. We suggest that further studies are needed to characterize the underlying molecular mechanisms of transplanted myoblasts derived from hiPS cells for the formation of mature human skeletal muscle.