Upregulation of p67phoxand gp91phoxin aortas from angiotensin II-infused mice

Abstract

Although NAD(P)H oxidase-derived superoxide (O2−) is increased during the development of angiotensin II (ANG II)-dependent hypertension, vascular regulation at the protein level has not been reported. We have shown that four major components of NAD(P)H oxidase are located primarily in the vascular adventitia as a primary source of vascular O2−. Here we compare vascular levels of O2−and NAD(P)H oxidase in normotensive and ANG II-infused hypertensive mice and show that, after 7 days of ANG II infusion (750 μg · kg−1· day−1ip) in C57B1/6 mice, systolic blood pressure was increased compared with that after sham infusion, concomitant with increased O2−in the thoracic aorta as measured using lucigenin (25 μM)-enhanced chemiluminescence. Both p67phoxand gp91phoxwere detectable by Western blotting in aortic homogenates, and we observed increased protein levels of NAD(P)H oxidase subunits. These ANG II-induced increases were normalized by simultaneous treatment with the AT1receptor antagonist losartan. Moreover, the primary location of these subunits was the adventitia as detected immunohistochemically. Our results suggest that ANG II-induced increases in O2−are due to increased adventitial NAD(P)H oxidase activity, brought about by the heightened expression and interaction of its components.