Effects of AMPKα1 downregulation on AdipoRon-mediated changes in basal and PDGF-induced mTOR signaling and cyclin D1 expression in VSMCs. VSMCs were transfected with scrambled (Scr.) or AMPKα1 siRNA and maintained in culture for 48 hr. Subsequently, serum-deprived VSMCs were incubated with A-C) AdipoRon (25 μM) for 3 hr followed by stimulation with PDGF (30 ng/ml) for 6 min; or D) Adiporon (25 μM) for 30 min followed by exposure to PDGF (30 ng/ml) for 48 hr. VSMC lysates were then subjected to immunoblot analysis using the primary antibodies specific for AMPKα1, pp70S6K, p70S6K, pS6, S6, p4E-BP1, 4E-BP1 and cyclin D1. β-actin was used as internal control. The data shown in the bar graphs are the means ± SEM. * p < 0.05 compared with control (− PDGF and 0 μM AdipoRon) [C and D] or Scr. siRNA (B). # p < 0.05 compared with PDGF (+ PDGF and 0 μM AdipoRon) [C and D]. Statistical significance was determined by applying unpaired student t test (B) or two-way ANOVA followed by Bonferroni multiple comparisons test (C and D) (n = 3).