Myostatin is an inhibitor of myogenic differentiation

Myostatin (MSTN), atransforming growth factor (TGF)- superfamily member, has been shownto negatively regulate muscle growth by inhibiting muscle precursorcell proliferation. Here, we stably transfectedC₂C₁₂ cells with mouse MSTN cDNA to investigateits possible role in myoblast differentiation. We found that MSTN cDNAoverexpression reversibly inhibits the myogenic process by downregulating mRNA levels of the muscle regulatory factors myoD andmyogenin, as well as the activity of their downstream target creatinekinase. Taking into consideration that MSTN expression duringdevelopment is restricted to muscle, our results suggest that MSTNprobably regulates myogenic differentiation by an autocrine mechanism.