Abstract 1205: Role for Nox1 NADPH Oxidase in Atherosclerosis

Abstract

NADPH oxidase-derived reactive oxygen species (ROS) contribute to the pathobiology of vascular disease. However, studies investigating NADPH oxidases in atherosclerosis have been limited in their ability to distinguish between the role of vascular cell and inflammatory cell -derived ROS. In this study, we examined the contribution of Nox1-derived ROS in a mouse model of atherosclerosis. Nox1 is a primary catalytic subunit of vascular cell, but not inflammatory cell, NADPH oxidase. At weaning, male apolipoprotein E deficient mice (AS, n=12) and male mice deficient in both apolipoprotein E and Nox1 (AS/Nox, n=16) received an atherogenic diet for 18 weeks. Mean blood pressures (116±3 vs. 110 ±3 mmHg; AS vs. AS/Nox, n=6), weights, and serum cholesterol levels (1578±150 vs. 1631±80 mg/dl; AS vs. AS/Nox) were similar between the AS and AS/Nox mice. As measured by lucigenin-enhanced chemiluminescence, superoxide levels were increased in segments of thoracic aorta from AS mice as compared to aorta from control mice (22±2 vs. 14±2 RLU/sec/mm 2 ; AS vs. C57BL/6; p<0.05, n=6). In contrast, superoxide levels in segments of thoracic aorta from AS/Nox mice were significantly lower (9±1 RLU/sec/mm 2 , n=6) than both AS and C57BL/6 mice. Dihydroethidium staining confirmed decreased superoxide levels in aorta of AS/Nox mice. Atherosclerotic lesion area was measured by staining the aorta en face with Oil Red O. Although atherosclerotic lesion area was reduced over the entire length of aorta in AS/Nox mice as compared to AS mice (10±1% vs. 14±1%, p<0.01), the reduction in lesion was primarily limited to the aortic arch (28±3% vs. 43±2%, p<0.001). In summary, Nox1 contributes to generation of ROS and lesion formation in atherosclerosis. These data confirm a role for vascular cell NADPH oxidases, and in particular Nox1, in vascular disease.