The contribution of Nox4 to NADPH oxidase activity in mouse vascular smooth muscle

Abstract

NADPH oxidases are important sources of reactive oxygen species (ROS) in the vasculature. In phagocytic cells, the catalytic subunit of NADPH oxidase is a glycoprotein, gp91phox. However, vascular smooth muscle cells (VSMCs), which show prominent NADPH oxidase activity, lack gp91phox. Hence, we examined the role of Nox4, a gp91phox homologue, in superoxide production in mouse-cultured VSMCs. Incubation of VSMCs with NADPH increased ROS production whether detected by lucigenin-enhanced chemiluminescence or dichlorofluorescein. Superoxide production was inhibited by the NADPH oxidase inhibitors, diphenyleneiodonium and apocynin, but not by inhibitors of other potential sources of superoxide. I..