Resveratrol Suppresses Angiotensin II-Induced Akt/Protein Kinase B and p70 S6 Kinase Phosphorylation and Subsequent Hypertrophy in Rat Aortic Smooth Muscle Cells

Resveratrol (RV), a polyphenolic substance found in grape skin, is proposed to account in part for the protective effect of red wine in the cardiovascular system. Angiotensin II (Ang II)-induced hypertrophy of vascular smooth muscle cells (VSMCs) is a pivotal step in the development of cardiovascular disease. The aims of this study were to test the hypothesis that RV may alter Ang II-mediated hypertrophic VSMC growth and to identify the putative underlying signaling pathways. We show that RV indeed potently inhibits Ang II-induced [ 3 H]leucine incorporation in a concentration-dependent manner (50 μM RV, 71% inhibition). Western blot analysis reveals that phosphorylation of Akt/protein kinase B (PKB) and to a lesser extent the mitogen-activated protein kinase extracellular signal-regulated kinase (ERK) 1/2, both essentially involved in Ang II-mediated hypertrophy, is dose dependently reduced by RV. Consistent with these results, we show that RV attenuates phosphorylation of the p70 ribosomal protein S6 kinase (p70 S6K ), a kinase downstream of the ERK 1/2 as well as the Akt pathway, that is implicated in Ang II-induced protein synthesis. Upstream of Akt/PKB RV seems to mediate its antihypertrophic effect by inhibiting phosphorylation of the phosphatidylinositol 3-kinase (PI 3 K) rather than by activating phosphatases. In summary, we demonstrate for the first time that RV inhibits Ang II-induced VSMC hypertrophy, possibly by interfering mainly with the PI 3 K/Akt and p70 S6K but also with the ERK 1/2 signaling pathway. Thus, this study delivers important new insight in the molecular pathways that may contribute to the proposed beneficial effects of RV in cardiovascular disease.