An isoflavone compound daidzein elicits myoblast differentiation and myotube growth

Preservation of muscle stem cell function is critical for muscle homeostasis and the regenerative capacity of stem cells declines with age, leading to muscle loss. Previously, daidzein, a natural isoflavone from Leguminosae, has been shown to prevent TNF-α-induced muscle atrophy. However, the molecular mechanisms of daidzein in these processes are currently unknown. In this study, we demonstrate a positive effect of black soybean extract (BS Ext) and daidzein on myoblast differentiation and myotube growth. Daidzein prevents dexamethasone-induced myotube atrophy through Akt activation. The promyogenic effect of BS Ext and daidzein is mediated through two promyogenic kinases, Akt and p38MAPK that in turn activates a key myogenic transcription factor MyoD. Additionally, BS Ext and daidzein promote myotube growth through Akt/mTOR/S6K pathway. Finally, daidzein augments MyoD-dependent myogenic conversion of mouse embryonic fibroblasts. Taken together, our data suggest that daidzein promotes myogenic differentiation and myotube hypertrophy through p38 and Akt/mTOR/S6K pathway.