Proliferative effect of PDGF and anti-proliferative activity of AMPK on vascular smooth muscle cells

AIM: To investigate the proliferative effect of platelet-derived growth factor (PDGF) and anti-proliferative activity of AMP-activated protein kinase (AMPK) on vascular smooth muscle cells (VSMCs). METHODS: The proliferation of VSMCs cultured with PDGF and activation of AMPK were observed. VSMCs were divided in 4 groups: control group; PDGF group; 5-aminoimidazole-4 -carboxamide-1-β-D-riboside (AICAR) group and AICAR+PDGF group. The time course of AMPK activation was determined. The protein level of mTOR was also measured. RESULTS: Compared with control group, the proliferative rate in PDGF group was significantly increased. The growth of VSMCs was inhibited in a time-dependent manner and the activity of p-mTOR was significantly decreased in AICAR group. Compared with control group, the expression of p-AMPK in PDGF group was significantly decreased, and that in AICAR group and AICAR+PDGF group was significantly increased. The expression of p-AMPK in AICAR+PDGF group was higher than that in PDGF group. The activity of p-mTOR in PDGF group was significantly higher than that in control group, while that of AICAR group and AICAR+PDGF group was significantly decreased. The expression of p-mTOR in AICAR+PDGF group was lower than that in PDGF group. CONCLUSION: Stimulation of VSMCs with PDGF promotes the cell proliferation, which can be inhibited by AICAR. The proliferation of VSMCs activated by AMPK is probably correlated with the down-regulation of mTOR expression.