Possible involvement of Rho-kinase in aldosterone-induced vascular smooth muscle cell remodeling.

There is increasing evidence supporting potential roles of aldosterone in the pathogenesis of vascular injury. The present study aimed to determine the involvement of Rho-kinase in aldosterone-induced vascular smooth muscle cell (VSMC) remodeling. In cultured rat VSMC, the effects of aldosterone on Rho-kinase activity, the reorganization of the cytoskeleton and cellular migration were examined. Aldosterone (1 nmol/L) significantly increased phosphorylation of myosin phosphate target subunit-1 (MYPT1), a marker of Rho-kinase activity, and the amount of GTP-Rho with a peak at 90 min in VSMC. Aldosterone also stimulated VSMC stress fiber formation and migration. These effects of aldosterone were markedly attenuated by pretreatment with eplerenone (10 micromol/L), a selective mineralocorticoid receptor antagonist, or Y27632 (10 micromol/L), a specific Rho-kinase inhibitor. These findings indicate that Rho-kinase is involved in the pathogenesis of aldosterone-induced VSMC remodeling.