NADPH oxidase p47phox siRNA attenuates adventitial fibroblasts proliferation and migration in apoE(-/-) mouse

BACKGROUND: Reactive oxide species (ROS) derived from NADPH oxidases is involved in atherosclerosis. However, as a key component of NADPH oxidase, how p47phox regulates NADPH oxidases activity, ROS production and adventitial fibroblasts (AFs) function remains unclear. METHODS: p47phox in aortic arteries of apoE(-/-) mice fed with hyperlipid diet was detected by immunohistochemistry. NADPH oxidase activity, superoxide anion (O(2)(−)) generation and p47phox expression were analyzed in primary AFs treated by diphenyleneiodonium (DPI). The proliferation and migration of AFs were also analyzed. RESULTS: p47phox expression was low in the aortic adventitia but high in the site of intimal injury with continuous hyperlipidic diet. Compared to AFs from wild-type mice, AFs derived from apoE(-/-) mice exhibited elevated NADPH oxidase activity, O(2)(−) production and higher mRNA and protein levels of p47phox, correlated with increased capability of proliferation and migration. DPI inhibited NADPH oxidase activity and AFs proliferation and migration in a dose-dependent manner. In addition, siRNA mediated knockdown of p47phox attenuated the proliferation and migration of AFs derived from apoE(-/-) mice. CONCLUSION: p47phox plays a critical role in the regulation of adventitial fibroblast proliferation and migration and may be a new therapeutic target for neointimal hyperplasia.