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Circulation. 2004 Jul 27;110(4):444-51. Epub 2004 Jul 19.

AMP-activated protein kinase inhibits angiotensin II-stimulated vascular smooth muscle cell proliferation.

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  • 1Department of Internal Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.

Abstract

BACKGROUND:

AMP-activated protein kinase (AMPK) is a stress-activated protein kinase that works as a metabolic sensor of cellular ATP levels. Here, we investigated whether AMPK signaling has a role in the regulation of the angiotensin II (Ang II)-induced proliferation signal in rat vascular smooth muscle cells (VSMCs).

METHODS AND RESULTS:

Aminoimidazole-4-carboxamide-1-beta-ribofuranoside (AICAR) activated AMPK in rat VSMCs and inhibited Ang II-induced extracellular signal-regulated kinase 1/2 phosphorylation but not that of p38 MAPK or Akt/PKB. Although Ang II activated AMPK, this activation was significantly inhibited by catalase, N-acetylcysteine, and diphenyleneiodonium chloride, an NADPH oxidase inhibitor. Moreover, the observation that AMPK was activated by H2O2 suggests that AMPK is redox sensitive. The Ang II type 1 receptor antagonist valsartan but not the Ang II type 2 receptor antagonist PD123319 significantly inhibited Ang II-induced AMPK activation, suggesting that Ang II-induced AMPK activation was Ang II type 1 receptor dependent. Whereas 3H-thymidine incorporation by VSMCs treated with Ang II was significantly inhibited when the cells were pretreated with 1 mmol/L AICAR, the inhibition of AMPK by dominant-negative AMPK overexpression augmented Ang II-induced cell proliferation. Subcutaneous injection of AICAR (1 mg/g body weight per day) for 2 weeks suppressed neointimal formation after transluminal mechanical injury of the rat femoral artery.

CONCLUSIONS:

Our findings indicate that Ang II-induced AMPK activation is synchronized with extracellular signal-regulated kinase signaling and that AMPK works as an inhibitor of the Ang II proliferative pathway. AMPK signaling might serve as a new therapeutic target of vascular remodeling in cardiovascular diseases.

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