Figure 2.

Adiponectin induces S1P biosynthesis. (a) C2C12 myotubes were incubated for the indicated time intervals in the absence or in the presence of 1 µg/mL Adn. Western blot analysis was performed using specific anti-phospho-SK1 and anti-phospho-SK2 antibodies. A blot representative of at least three independent experiments with analogous results is shown. The histogram represents densitometric analysis of three independent experiments each performed in triplicate. Data are the mean ± SEM and are reported as protein expression normalized to GAPDH, fold change over control (set as 1). The increase in phospho-SK1 and phospho-SK2 content induced by Adn was found to be statistically significant by one-way ANOVA followed by Bonferroni’s post hoc test (* p < 0.05, treated vs. control). (b) C2C12 myotubes were incubated for 1 h in the absence or in the presence of 1 µg/mL Adn before the media were collected (left panel) and cells harvested (right panel) and then subjected to Sph and S1P analysis. Results are reported as mean ± SEM of fmol/mL (media) or pmol (cell lysates) of S1P and Sph normalized on protein content. The increase of S1P and Sph levels induced by Adn was statistically significant by Student’s t-test * p < 0.05, treated vs Ctrl.