Figure 2. Hepatocyte growth factor activates protein synthesis pathway and increases protein expression of myogenic factors.

In order to establish if HGF initiated the protein synthesis and myogenesis pathways and the timeframe in vivo, we injected a total of 21 normoxic mice (N = 3 for each time point) with hepatocyte growth factor (20 ng HGF/g body weight) and sacrificed them at time points between 0 and 48 h. A western blot of components of the protein synthesis and myogenesis pathways demonstrates how the signal activates the different proteins with time and eventually leads to an increased expression of myogenic factors (A). Two mice were given a 10 times higher dose of hepatocyte growth factor (200 ng HGF/g body weight) and sacrificed after 60 min ( = 60 minH). Western blots of tibialis anterior homogenates (N = 3 for each time point) shows activation of protein synthesis pathway through phosphorylation of PDK1 (B)/mTOR (C)/Akt (D)/p70S6K (E), and increased protein expression of myogenic factors MyoD (F) and myogenin (G). A 200 ng HGF/g body weight dose of hepatocyte growth factor yields a diminished response compared to a 20 ng HGF/g body weight dose RU = Relative Units. Error bars are SD. Thin dividing lines on the blot are for clarification only whereas the bold red line symbolizes that samples were run on two separate gels. One-way ANOVA with Bonferroni post hoc correction for multiple comparisons was used to assess differences among groups for each dependent variable. *denotes significant (P<0.05). Data are representative of one independent experiment.