Pulmonary artery NADPH-oxidase is activated in hypoxic pulmonary vasoconstriction
Pulmonary artery NADPH-oxidase is activated in hypoxic pulmonary vasoconstriction
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DOI：
10.1165/ajrcmb.15.5.8918370
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发表时间：
1996-11-01
影响因子：
6.4
通讯作者：
Marshall, BE
中科院分区：
文献类型：
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作者：
Marshall, C;Mamary, AJ;Marshall, BE
NADPH-氧化酶复合体包含至少两个蛋白质组分(gp91-Phox和p22-Phox)和独特的低氧化还原电位(-245 mV)细胞色素b(-245)，是中性粒细胞中细菌杀灭所产生的超氧化物的来源，已被认为是颈动脉体氧传感器。在小牛肺小动脉(直径300微米)的纯培养的平滑肌细胞中，用单抗48进行Western印迹分析，证明存在这种细胞色素特异性的91kD蛋白。这些细胞匀浆的低温差示光谱显示，当在-152 mV和-345 mV的氧化还原电位之间滴定时，具有特征的细胞色素b(-245)光谱，与低氧化还原电位形式一致。当这些细胞暴露于低氧(类似于40毫米汞)时，超氧化物歧化产物从1.4+/-0.2增加到73+/-12nmol.min(-1)mg(-1)蛋白。NADPH酶抑制剂二苯基碘(DPI：10mM)可抑制缺氧性超氧化物的产生，而线粒体抑制剂咪唑硫唑(10mM)则不能抑制缺氧性超氧化物的生成，缺氧性超氧化物的增加明显高于大、小动脉的血管。荧光免疫细胞化学显示NADPH-氧化酶蛋白存在于大鼠肺切片的肺动脉壁中，共聚焦显微镜显示该复合体广泛分布于动脉平滑肌壁附近。在低氧或去甲肾上腺素(NP)引起的猫肺动脉环血管收缩中，DPI对低氧抑制的敏感性(ED(50)=0.8mM)明显高于NP引起的收缩(ED(50)=13.4mU M)。综上所述，这些观察结果表明，含有NADPH-氧化酶的独特细胞色素b(-245)存在于肺动脉平滑肌中，在低氧条件下，NADPH-氧化酶或NADH-氧化还原酶复合体被激活以释放超氧化物。结论：跨膜NADPH-氧化酶可能参与了缺氧性肺血管收缩的启动。
An NADPH-oxidase complex containing at least two protein components (gp91-phox and p22-phox) and a unique low redox potential (-245mV) cytochrome b(-245) is the source of superoxide generated for bacterial killing in neutrophils and has been suggested as the oxygen sensor in the carotid body. In pure cultures of smooth muscle cells from calf small pulmonary arteries (300 mu m diameter) the presence of the 91 kD protein specific to this cytochrome was demonstrated by Western blot analysis with monoclonal antibody 48. Low-temperature-difference spectrophotometry of homogenates of these cells demonstrated the characteristic cytochrome b(-245) spectrum when titrated between redox potentials of -152 and -345 mV, consistent with the low redox potential form. When these same cells were exposed to hypoxia (similar to 40 mmHg), superoxide production increased significantly from 1.4 +/- 0.2 to 73 +/- 12 nmoles.min(-1) mg(-1) protein. Hypoxic generation of superoxide was inhibited by the NADPH-oxidase inhibitor diphenyleneiodonium (DPI: 10 mu M) but not by the mitochondrial inhibitor myxathiazole (10 mu M), The hypoxic superoxide increase was significantly greater than that observed from smooth muscle cells from large pulmonary arteries or from large or small systemic arteries. Fluorescence immunocytochemistry revealed the presence of the NADPH-oxidase protein in the walls of pulmonary arteries in rat lung slices, and confocal microscopy showed the complex to be widely distributed in the vicinity of the arterial smooth muscle walls. In hypoxia or norepinephrine (NP)-induced vasoconstriction of pulmonary artery rings from cats, the sensitivity to inhibition by DPI was observed to be significantly greater for hypoxia (ED(50) = 0.8 mu M) than for NP-induced (ED(50) = 13.4 mu M) constriction. Together these observations demonstrate that the unique cytochrome b(-245) containing NADPH-oxidase is present in pulmonary artery smooth muscle and that an NADPH-oxidase or NADH-oxidoreductase complex is activated to release superoxide by hypoxic conditions. It is concluded that a trans-membrane NADPH-oxidase is the most likely and that activation of this system may be involved in the initiation of hypoxic pulmonary vasoconstriction.