Phagocytic NADPH Oxidase-Dependent Superoxide Production Stimulates Matrix Metalloproteinase-9: Implications for Human Atherosclerosis

G. Zalba, A. Fortuno, J. Orbe, G. San Jose, M. U. Moreno, M. Belzunce, J. A. Rodriguez, O. Beloqui, J. A. Paramo, J. Diez
2007 Arteriosclerosis, Thrombosis and Vascular Biology  
Objective-Data suggest that matrix metalloproteinase-9 (MMP-9) has a role in atherosclerosis. The phagocytic NADPH oxidase has been also associated with atherosclerosis. This study aimed to investigate the association between phagocytic NADPH oxidase and MMP-9 in human atherosclerosis. Methods and Results-In vitro experiments performed in human monocytes showed that NADPH oxidase activation enhanced MMP-9 secretion and activity, determined by enzyme-linked immunosorbent assay and zymography,
more » ... and zymography, respectively. Immunohistochemical study showed that phagocytic NADPH oxidase localized with MMP-9 in endarterectomies from patients with carotid stenosis. In addition, a positive relationship (PϽ0.001) was found between phagocytic NADPH oxidase-dependent superoxide production determined with lucigenin and plasma MMP-9 levels in 188 asymptomatic subjects free of overt clinical atherosclerosis. In multivariate analysis, this association remained significant after adjustment for cardiovascular risk factors. Interestingly, subjects in the upper quartile of superoxide production exhibited the highest values of MMP-9, oxidized low-density lipoprotein, nitrotyrosine, carotid intima media thickness, and an increased presence of carotid plaques. Conclusions-Enhanced NADPH oxidase-dependent ⅐O 2 Ϫ production stimulates MMP-9 in monocytes and this relationship may be relevant in the atherosclerotic process. Moreover, MMP-9 emerges as an important mediator of the phagocytic NADPH oxidase-dependent oxidative stress in atherosclerosis. (Arterioscler Thromb Vasc Biol. 2007;27: 587-593.) Key Words: atherosclerosis Ⅲ NADPH oxidase Ⅲ superoxide Ⅲ MMP T he NADPH oxidase systems, which constitute the most important sources of superoxide (⅐O 2 Ϫ ) in the vessel wall, are present in endothelial cells, smooth muscle cells (SMCs), fibroblasts, and infiltrated monocytes/macrophages. 1,2 The phagocytic NADPH oxidase consists of a membraneassociated cytochrome b 558 , which comprises gp91 phox and p22 phox subunits, and cytosolic components p47 phox , p67 phox , and rac. 2 Several studies have shown a key role for vascular NADPH oxidase isoforms in the development of human atherosclerosis. 3-7 Interestingly, phagocytic NADPH oxidase seems to play also a key role in the development and progression of atherosclerotic lesion. 5-7 Recently, enhanced phagocytic NADPH oxidase-dependent ⅐O 2 Ϫ production has been correlated positively with carotid intima-media thickness (IMT), a surrogate marker of atherosclerosis. 8 Metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases capable as a class of degrading extracellular matrix components, which participate in the atherosclerotic process by remodeling the extracellular matrix. 9 Available evidence substantiates that plasma MMP-9 levels correlate with the presence of atherosclerosis 10 and represent an independent risk factor for atherothrombotic events (ie, coronary heart disease events and cerebrovascular disease). 11,12 Thus, plasma MMP-9 levels can provide a useful emerging plasma biomarker in the prediction of atherothrombotic events. 13 Whereas NADPH oxidase-mediated ⅐O 2 Ϫ generation participates in MMP-2 and MMP-9 activation in cardiomyocytes, endothelial cells, and SMCs, 14 -18 no data are available on its ability to regulate MMPs in blood phagocytic cells. We therefore hypothesized that an association may exist between phagocytic NADPH oxidase and MMP-9 in human atherosclerosis. To test this hypothesis, we performed the study at 3 levels; (1) we analyzed in vitro the ability of NADPH oxidase to regulate MMP-9 in human monocytes; (2) we studied the association between NADPH oxidase and MMP-9 in athero-
doi:10.1161/01.atv.0000256467.25384.c6 pmid:17194891 fatcat:ezy2qln2wffajbiyjxqogx6fv4