Fine tuning of Piezo1 Expression and Activity Ensures Efficient Myoblast Fusion during Skeletal Myogenesis

Mechanical stimuli such as stretch and resistance training are essential to regulate growth and function of skeletal muscle. However, the molecular mechanisms involved in sensing mechanical stress during muscle formation remain unclear. Here, we investigate the role of the mechano-sensitive ion channel Piezo1 during myogenic progression. Direct manipulation of Piezo1 in muscle stem cells alters their myogenic progression. Indeed, Piezo1 knockdown suppresses myoblast fusion leading to smaller myotubes. Such event is accompanied by significant downregulation of the fusogenic protein Myomaker. In parallel, while Piezo1 knockdown also lowers Ca2+ influx in response to stretch, Piezo1 activation increases Ca2+ influx in response to stretch and enhances myoblasts fusion. We believe these findings may help understand molecular defects present in some muscle diseases. Altogether our study shows that Piezo1 is essential for terminal muscle differentiation acting on myoblast fusion, suggesting that Piezo1 deregulation may have implications in muscle aging and degenerative diseases including muscular dystrophies.