Inhibitory effect of Hsp70 on angiotensin II-induced vascular smooth muscle cell hypertrophy

Angiotensin Ⅱ (Ang Ⅱ), which is an important mediator of both vascular responsiveness and growth, has been shown to induce vascular smooth muscle cell (VSMC) hypertrophy via the activation of a complex series of intracellular signaling events. Heat shock protein 70 (Hsp70) has recently been shown to protect against Ang Ⅱ-induced hypertension. In this study, we tested the hypothesis that Hsp70 can protect VSMC from Ang Ⅱ-induced hypertrophy. We treated VSMCs with Ang Ⅱ to induce hypertrophy and to activate MAPK signaling pathway. We observed that the augmentation of Hsp70 expression inhibited Ang Ⅱ-stimulated VSMC hypertrophy. This inhibitory effect of Hsp70 appears to be partly due to extracellular signal-regulated kinase (ERK½) in - activation, which in turn, may possibly result from the accumulation of MAP kinase phosphatase-1 (MKP-1).