The Essential Role of Stathmin in Myoblast C2C12 for Vertical Vibration-Induced Myotube Formation.

Vertical vibration (VV) is a type of whole body vibration, which induces muscle contraction through vibration to improve muscle strength and bone density. However, the mechanism of VV on muscle cell myotube formation is still unclear. In the current study, we aim to clarify the mechanism involved in VV's stimulation of myotube formation. In order to identify the molecules regulated by VV, we performed proteomics analysis including 2D electrophoresis combined with MALDI-TOF/TOF Mass. Stathmin was identified as a high potential molecule responding to VV stimulation, and we found that under VV stimulation, the expression of stathmin gene and protein increased in a time-dependent manner. In addition, we also confirmed that the increase of stathmin stimulated by VV is mediated through the PI3K/Akt pathway. Furthermore, stathmin siRNA significantly down-regulated the expression of myogenic regulatory factor (MRF) MyoD, decorin, and type I collagen (Col-I), and down-regulated the cellular process regulators such as FGF7, TGFBr1 and PAK3. Taken together, our results confirm that under the stimulation of VV, PI3K/Akt and stathmin would be activated, as well as the up-regulation of MRFs, such as FGF7, TGFBr1 and PAK3 to initiate myogenesis. It also showed that the response of MRF to VV stimulation was significantly related to stathmin expression, which also confirmed the importance of stathmin in the entire myotube formation process. This study may provide evidence of stathmin as a biological indicator of VV to increase muscle strength.