No abstract

The regulation of adult skeletal muscle repair and regeneration is largely due to the contribution of resident adult myogenic precursor cells called satellite cells. The events preceding their participation in muscle repair include activation (exit from quiescence), proliferation, and differentiation. This study examined the effects of transforming growth factor-beta (TGF-β1) on satellite cell activation, determined whether TGF-β1 could maintain quiescence in the presence of hepatocyte growth factor (HGF), and whether the regulation of satellite cell activation with TGF-β1 improves the ability of satellite cells to withstand oxidative stress. The addition of TGF-β1 during early satellite cell activation (0-48 h) or during the proliferative phase (48-96 h) maintained and induced satellite cell quiescence, respectively, as determined by myogenic differentiation (MyoD) protein expression. TGF-β1 also attenuated satellite cell activation when used with HGF. Finally, the role of quiescence in protecting cells against oxidative stress was examined. TGF-β1 treatment and the low pH satellite cell preparation procedure, a technique that forestalls spontaneous activation in vitro, both enhanced survival of cultured satellite cells following hydrogen peroxide treatment. These findings indicate that TGF-β1 is capable of maintaining and inducing satellite cell quiescence and suggest methods to maintain satellite cell quiescence may improve their transplantation efficiency.