Role of angiotensin II and angiotensin II receptors in vascular smooth muscle cell migration in vitro.

OBJECTIVE: To determine the biotic effects of angiotensin II (Ang II) on the migration of rat smooth muscle cells (VSMCs) and investigate the mechanisms involved in the development of vascular injury. METHODS: VSMCs isolated from aortic media of Wistar rats and cultured by the modified explant method were adopted. In the presence and absence of Ang II, the expression of Ang II receptor (ATR) and reorganization of the actin cytoskeleton and focal adhesion of VSMCs were studied by an immunocytochemistry technique and fluorocytochemistry technique. Migration assays were performed with a modified Boyden's chamber. The effects of AT(1)R antagonist (CV-11974), AT(2)R antagonist (PD123319) on the aforementioned target were studied. RESULTS: VSMCs migration was stimulated by adding Ang II. The dynamic reorganization of actin cytoskeleton and focal adhesions may be an important mechanism by which Ang II facilitates VSMCs motility. The expression of AT(1)R in VSMCs could be upregulated initially after treatment with Ang II, then decreased gradually. The expression of AT(1)R was downregulated by AT(1)R antagonists. The effect of Ang II on VSMCs migration was mediated by AT(1)R, while AT(2)R had no significant effect. CONCLUSIONS: The dynamic reorganization of focal adhesions and the actin cytoskeleton is required for Ang II-induced VSMCs migration. This effect is mediated by AT(1)R.