It has been reported that microRNA-130a (miR-130a) targets GAX, the growth arrest-specific homeobox, which inhibits proliferation, differentiation, and migration of vascular smooth muscle cells (VSMCs). In the present study, we therefore investigated the effect of miR-130a on proliferation of cultured VSMCs and the potential role of miR-130a in vascular remodeling during hypertension.

Proliferation of VSMCs was determined by 5-bromo-2′-deoxyuridine (BrdU) incorporation method. The expression of miR-130a and GAX was analyzed by quantitative reverse transcription-PCR. The protein expression of GAX was analyzed by western blot. The mimic and inhibitor of miR-130a were used in gain-of-function and loss-of-function in vitro studies, respectively. The correlation of miR-130a with vascular remodeling was observed in spontaneously hypertensive rats (SHRs).

MiR-130a mimic at the concentration of 25 or 50nmol/l significantly promoted proliferation of VSMCs. The expression of miR-130a was upregulated in the remodeled aorta and superior mesenteric artery of SHRs. The expression of GAX was downregulated in VSMCs transfected with miR-130a mimic and in thoracic aorta and superior mesenteric artery of SHRs. Angiotensin II (Ang II) promoted proliferation of VSMCs and upregulated miR-130a expression concomitantly with a decreased GAX expression in a concentration- and time-dependent manner. The proliferative effects of Ang II on VSMCs were suppressed partly by the miR-130a inhibitor.

These results suggest that miR-130a is a novel regulator of proliferation of VSMCs via inhibiting the expression of GAX, which may contribute to vascular remodeling in hypertension.

American Journal of Hypertension advance online publication 14 July 2011; doi:10.1038/ajh.2011.116