Ushio-Fukai M, Zafari A M, Fukui T, Ishizaka N, Griendling K K
Department of Medicine, Division of Cardiology, Emory University, Atlanta, Georgia 30322, USA.
J Biol Chem. 1996 Sep 20;271(38):23317-21. doi: 10.1074/jbc.271.38.23317.
Superoxide anion formation is vital to the microbicidal activity of phagocytes. Recently, however, there is accumulating evidence that it is also involved in cell growth in vascular smooth muscle cells (VSMCs). We have shown that the hypertrophic agent angiotensin II stimulates superoxide production by activating the membrane-bound NADH/NADPH oxidase and that inhibition of this oxidase attenuates vascular hypertrophy. However, the molecular identity of this oxidase in VSMCs is unknown. We have recently cloned the cytochrome b558 alpha-subunit, p22(phox) (one of the key electron transfer elements of the NADPH oxidase in phagocytes), from a rat VSMC cDNA library, but its role in VSMC oxidase activity remains unclarified. Here we report that the complete inhibition of p22(phox) mRNA expression by stable transfection of antisense p22(phox) cDNA into VSMCs results in a decrease in cytochrome b content, which is accompanied by a significant inhibition of angiotensin II-stimulated NADH/NADPH-dependent superoxide production, subsequent hydrogen peroxide production, and [3H]leucine incorporation. We provide the first evidence that p22(phox) is a critical component of superoxide-generating vascular NADH/NADPH oxidase and suggest a central role for this oxidase system in vascular hypertrophy.
超氧阴离子的形成对于吞噬细胞的杀菌活性至关重要。然而，最近有越来越多的证据表明，它也参与血管平滑肌细胞（VSMC）的细胞生长。我们已经表明，肥大因子血管紧张素II通过激活膜结合的NADH/NADPH氧化酶来刺激超氧产生，并且抑制这种氧化酶可减轻血管肥大。然而，VSMC中这种氧化酶的分子身份尚不清楚。我们最近从大鼠VSMC cDNA文库中克隆了细胞色素b558α亚基p22(phox)（吞噬细胞中NADPH氧化酶的关键电子传递元件之一），但其在VSMC氧化酶活性中的作用仍未阐明。在此我们报告，通过将反义p22(phox) cDNA稳定转染到VSMC中完全抑制p22(phox) mRNA表达，会导致细胞色素b含量降低，同时伴随着对血管紧张素II刺激的NADH/NADPH依赖性超氧产生、随后的过氧化氢产生以及[3H]亮氨酸掺入的显著抑制。我们提供了首个证据，表明p22(phox)是产生超氧的血管NADH/NADPH氧化酶的关键成分，并表明该氧化酶系统在血管肥大中起核心作用。
