Landmesser Ulf, Cai Hua, Dikalov Sergey, McCann Louise, Hwang Jinah, Jo Hanjoong, Holland Steven M, Harrison David G
Division of Cardiology, Emory University School of Medicine and Atlanta Veterans Administration Hospital, Atlanta, Ga 30322, USA.
Hypertension. 2002 Oct;40(4):511-5. doi: 10.1161/01.hyp.0000032100.23772.98.
Hypertension caused by angiotensin II is dependent on vascular superoxide (O2*-) production. The nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase is a major source of vascular O2*- and is activated by angiotensin II in vitro. However, its role in angiotensin II-induced hypertension in vivo is less clear. In the present studies, we used mice deficient in p47(phox), a cytosolic subunit of the NADPH oxidase, to study the role of this enzyme system in vivo. In vivo, angiotensin II infusion (0.7 mg/kg per day for 7 days) increased systolic blood pressure from 105+/-2 to 151+/-6 mm Hg and increased vascular O2*- formation 2- to 3-fold in wild-type (WT) mice. In contrast, in p47(phox-/-) mice the hypertensive response to angiotensin II infusion (122+/-4 mm Hg; P<0.05) was markedly blunted, and there was no increase of vascular O2*- production. In situ staining for O2*- using dihydroethidium revealed a marked increase of O2*-production in both endothelial and vascular smooth muscle cells of angiotensin II-treated WT mice, but not in those of p47(phox-/-) mice. To directly examine the role of the NAD(P)H oxidase in endothelial production of O2*-, endothelial cells from WT and p47(phox-/-) mice were cultured. Western blotting confirmed the absence of p47(phox) in p47(phox-/-) mice. Angiotensin II increased O2*- production in endothelial cells from WT mice, but not in those from p47(phox-/-) mice, as determined by electron spin resonance spectroscopy. These results suggest a pivotal role of the NAD(P)H oxidase and its subunit p47(phox) in the vascular oxidant stress and the blood pressure response to angiotensin II in vivo.
血管紧张素 II 所致高血压依赖于血管超氧化物（O2*-）的生成。烟酰胺腺嘌呤二核苷酸磷酸（NAD[P]H）氧化酶是血管 O2*- 的主要来源，且在体外可被血管紧张素 II 激活。然而，其在体内血管紧张素 II 诱导的高血压中的作用尚不清楚。在本研究中，我们使用缺乏 p47(phox)（NADPH 氧化酶的胞质亚基）的小鼠来研究该酶系统在体内的作用。在体内，野生型（WT）小鼠连续 7 天输注血管紧张素 II（每天 0.7 mg/kg）可使收缩压从 105±2 升高至 151±6 mmHg，并使血管 O2*- 生成增加 2 至 3 倍。相比之下，在 p47(phox-/-)小鼠中，对血管紧张素 II 输注的高血压反应（122±4 mmHg；P<0.05）明显减弱，且血管 O2*- 生成未增加。使用二氢乙锭对 O2*- 进行原位染色显示，血管紧张素 II 处理的 WT 小鼠的内皮细胞和血管平滑肌细胞中 O2*- 生成显著增加，而 p47(phox-/-)小鼠则未增加。为了直接检测 NAD(P)H 氧化酶在内皮细胞生成 O2*- 中的作用，培养了 WT 和 p47(phox-/-)小鼠的内皮细胞。蛋白质印迹证实 p47(phox-/-)小鼠中不存在 p47(phox)。通过电子自旋共振光谱法测定，血管紧张素 II 可增加 WT 小鼠内皮细胞中的 O2*- 生成，但不增加 p47(phox-/-)小鼠内皮细胞中的 O2*- 生成。这些结果表明，NAD(P)H 氧化酶及其亚基 p47(phox)在体内血管氧化应激以及对血管紧张素 II 的血压反应中起关键作用。
