Regulation of Skeletal Muscle Differentiation by Akt

Abstract

Akt plays an important role in a variety of cellular physiologies such as growth, proliferation, and differentiation. In skeletal muscle, Akt has been implicated in regulating regeneration, hypertrophy, and atrophy. In this study, the role of Akt has been examined during skeletal muscle differentiation. Culturing C2C12 myoblasts under low serum (1% horse serum) and high density converted cell morphology from a round shape to an elongated and multi-nucleated shape. Morphological changes were initiated from day 2 of differentiation. In addition, the expression of both myogenin G and myogenin D was elevated from day 2 of differentiation. Skeletal muscle differentiation was abolished by silencing Akt1 or Akt2, but was significantly enhanced by the over-expression of either Akt1 or Akt2. The activation of Akt was observed from day 2 of differentiation and disappeared after day 7. The expression of krüppel-like factor 4 was observed from day 6 of differentiation. Moreover, this expression was blocked in cells silencing either Akt1 or Akt2. In addition, the promoter activity of krüppel-like factor 4 was significantly reduced in cells silencing Akt1 or Akt2. These results suggest that Akt regulates skeletal muscle differentiation through the regulation of krüppel-like factor 4 expression.

Leucine promotes differentiation of porcine myoblasts through the protein kinase B (Akt)/Forkhead box O1 signalling pathway

“…Protein kinase B, also known as Akt, plays a critical role in control of myoblast differentiation ( 9 ) . Blockage of Akt or silencing of Akt inhibits the differentiation of skeletal muscle; however, overexpression of Akt gets an opposite result ( 10 , 11 ) . FoxO1 is one of FoxO family members, and it plays a significant role in regulating myoblast differentiation.…”