MFG-E8 protein promotes C2C12 myogenic differentiation by enhancing PI3K/Akt signaling

Abstract

Milk fat globule-EGF factor 8 (MFG-E8) protein can promote growth factor induced survival and proliferation of vascular endothelial cells, leading to angiogenesis. Little has been reported on the potential effects of MFG-E8 on cell differentiation and the molecular mechanism. In this study, MFG-E8, the major component of milk fat globule membrane (MFGM) protein (82.35%), was isolated and purified using cellulose DEAE-52. Its effects on myogenic differentiation of murine skeletal muscle C₂C₁₂ cells were investigated using qRT-PCR, Western blotting and immunofluorescence assay. MFG-E8 promoted the formation of multinucleated myotubes, and increased the fusion index. In addition, Akt-activity was significantly increased during MFG-E8 induced C₂C₁₂ cell differentiation, whereas wortmannin, a PI3K inhibitor, was able to block the differentiation of C₂C₁₂ cells promoted by MFG-E8. MFG-E8 enhanced the expression of the myogenic regulatory factor MyHC in C₂C₁₂ cells over time. Conversely, the expression of MyHC was also inhibited by wortmannin. We conclude that MFG-E8 promotes the differentiation of C₂C₁₂ cells by activating the PI3K/Akt signaling pathway. Taken together, these results show that MFG-E8 could exert a beneficial effect on C₂C₁₂ myoblast cell differentiation, and therefore, it may have potential as a differentiation-inducing agent for the therapy of sarcopenia.