Compound C (6-[4-(2-piperidin-1-yl-ethoxy)-phenyl0]3-pyridin-4-yl-pyrazolo[1,5-a] pyrimidine) is a cell-permeable pyrrazolopyrimidine derivative that acts as a potent inhibitor of adenosine monophosphate-activated protein kinase (AMPK). Although compound C is often used to determine the role of AMPK in various physiological processes, it also evokes AMPK-independent actions. In the present study, we investigated whether compound C influences vascular smooth muscle cell (SMC) function through the AMPK pathway. Treatment of rat aortic SMCs with compound C (0.02-10μM) inhibited vascular SMC proliferation and migration in a concentration-dependent fashion. These actions of compound C were not mimicked or affected by silencing AMPKα expression or by infecting SMCs with an adenovirus expressing a dominant-negative mutant of AMPK (AdAMPK-DN). In contrast, the pharmacological activator of AMPK 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside inhibited the proliferation and migration of SMCs in a manner that was strictly dependent on AMPK activity. Flow cytometry experiments revealed that compound C arrested SMCs in the G0/G1 phase of the cell cycle and this was associated with a decrease in cyclin D1 and cyclin A protein expression and retinoblastoma protein phosphorylation, and with an increase in p21 protein expression. Finally, local perivascular delivery of compound C immediately after balloon injury of rat carotid arteries markedly attenuated neointima formation. These studies identify compound C as novel AMPK-independent regulator of vascular SMC function that exerts inhibitory effects on SMC proliferation and migration, and neointima formation following arterial injury. Compound C represents a potentially new therapeutic agent in treating and preventing occlusive vascular disease.
- adenosine monophosphate-activated protein kinase
- cell cycle
- compound c
- smooth muscle cells
- Received March 17, 2011.
- Revision received April 28, 2011.
- Accepted May 4, 2011.
- The American Society for Pharmacology and Experimental Therapeutics