Adenosine monophosphate-activated protein kinase regulates platelet-derived growth factor-BB-induced vascular smooth muscle cell migration

Abstract

Migration of vascular smooth muscle cells (VSMCs) is essential for repair of vascular injury, development of atherosclerotic lesions and restenosis after angioplasty or by-pass graft surgery. It has been reported that platelet-derived growth factor (PDGF)-BB induces VSMC migration via the p44/p42 mitogen-activated protein (MAP) kinase pathway and the phosphatidylinositol 3 (PI3)-kinase/Akt pathway. Adenosine monophosphate-activated protein kinase (AMPK) is generally known to regulate multiple metabolic pathway. In the present study, we investigated the involvement of AMPK in PDGF-BB-induced migration of VSMCs using, a VSMC line, A10 cells. PDGF-BB induced phosphorylation of AMPK-α at Thr-172 residue. Treatment of A10 cells with compound C, an AMPK inhibitor, suppressed PDGF-BB-induced migration in a concentration-dependent manner (0.01-1μM). Compound C truly attenuated PDGF-BB induced phosphorylation of acetyl-CoA carboxylase, a downstream substance of AMPK. Downregulation of AMPK-α expression by the siRNA appeared an anti-migratory effect on PDGF-BB-induced migration. PDGF-BB-induced phosphorylation of c-Raf, MEK1/2 or p44/p42 MAP kinase, and phosphorylation of PI3-kinase or Akt were markedly suppressed by compound C. In conclusion, our results strongly suggest that PDGF-BB induces activation of AMPK in VSMCs, and subsequently regulates the migration via both the p44/p42 MAP kinase pathway and the PI3-kinase/Akt pathway.