Palmitate exerts opposite effects on proliferation and differentiation of skeletal myoblasts

Abstract The purpose of the study was to examine mechanisms controlling cell cycle progression/arrest and differentiation of mouse C2C12 myoblasts exposed to long‐chain saturated fatty acid salt, palmitate. Treatment of proliferating myoblasts with palmitate (0.1 mmol/l) markedly decreased myoblast number. Cyclin A and cyclin D1 levels decreased, whereas total p21 and p21 complexed with cyclin‐dependent kinase‐4 (cdk4) increased in myoblasts treated with palmitate. In cells induced to differentiation addition of palmitate augmented the level of cyclin D3, the early (myogenin) and late (α‐actinin, myosin heavy chain) markers of myogenesis, and caused an increase of myotube diameter. In conclusion, exposure to palmitate inhibits proliferation of myoblasts through a decrease in cyclin A and cyclin D1 levels and an increase of p21‐cdk4 complex formation; however, it promotes cell cycle exit, myogenic differentiation and myotube growth.