Abstract
6-[4-(2-Piperidin-1-yl-ethoxy)-phenyl]-3-pyridin-4-yl-pyrazolo[1,5-a] pyrimidine (compound C) is a cell-permeable pyrrazolopyrimidine derivative that acts as a potent inhibitor of AMP-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 (0.02–10 μM) 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 infecting SMCs with an adenovirus expressing a dominant-negative mutant of AMPK. In contrast, the pharmacological activator of AMPK 5-aminoimidazole-4-carboxamide-1-β-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 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 a novel AMPK-independent regulator of vascular SMC function that exerts inhibitory effects on SMC proliferation and migration and neointima formation after arterial injury. Compound C represents a potentially new therapeutic agent in treating and preventing occlusive vascular disease.
Footnotes
This work was supported by the National Institutes of Health National Heart, Lung and Blood Institute [Grants R01-HL74966, R01-HL59976, R01-HL77288]; and a University of Missouri Summer Research Internship in Cell and Molecular Biology (to B.Y.).
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.111.181784.
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ABBREVIATIONS:
- SMC
- smooth muscle cell
- compound C
- 6-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-3-pyridin-4-yl-pyrazolo[1,5-a] pyrimidine
- AMPK
- AMP-activated protein kinase
- AICAR
- 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside
- ACC
- acetyl-CoA-carboxylate
- siRNA
- small interfering RNA
- AdAMPK-DN
- adenovirus expressing a dominant-negative AMPK mutant
- AdGFP
- adenovirus expressing green fluorescent protein
- PBS
- phosphate-buffered saline
- NT
- nontargeting.
- Received March 17, 2011.
- Accepted May 4, 2011.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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