Cytosolic NADPH may regulate differences in basal Nox oxidase-derived superoxide generation in bovine coronary and pulmonary arteries
Cytosolic NADPH may regulate differences in basal Nox oxidase-derived superoxide generation in bovine coronary and pulmonary arteries
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DOI：
10.1152/ajpheart.00629.2004
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发表时间：
2005-01-01
影响因子：
4.8
通讯作者：
Wolin, MS
中科院分区：
文献类型：
--
作者：
Gupte, SA;Kaminski, PM;Wolin, MS
由于基础NAD（P）H氧化酶活性控制的系统似乎有助于内皮去除的牛冠状动脉（BCA）和肺动脉（BPA）对缺氧的反应的差异，我们表征了这些血管节段中存在的Nox氧化酶活性以及胞质NAD（P）H氧化还原系统如何控制氧化酶活性。BPA产生的光泽精（5 μ M）化学发光可检测的超氧化物比BCA多60 - 80%。夹竹桃素（10 μ M），一种NAD（P）H氧化酶抑制剂，和6-氨基烟酰胺（1 mM），一种戊糖磷酸抑制剂（PPP），两者都减弱（约50 - 70%）BPA和BCA中检测到的超氧化物。Western blot检测Nox 2和Nox 4 mRNA和蛋白表达无明显差异。NADPH和NADH增加超氧化物在匀浆和分离的微粒体膜组分的方式与BPA和BCA具有相似的氧化酶活性水平一致。BPA的NADPH水平比BCA高4.2倍。葡萄糖-6-磷酸脱氢酶（G6 PD）的活性和蛋白质水平，限速PPP酶产生细胞溶质NADPH，BPA比BCA高1.5倍。因此，BPA与BCA的不同之处在于它们具有更高水平的G6 PD活性，NADPH和超氧化物。由于两个动脉具有相似的Nox表达和活性水平，因此细胞溶质NADPH水平升高可能有助于BPA中超氧化物的增加。
Because systems controlled by basal NAD(P) H oxidase activity appear to contribute to differences in responses of endothelium-removed bovine coronary (BCA) and pulmonary (BPA) arteries to hypoxia, we characterized the Nox oxidases activities present in these vascular segments and how cytosolic NAD( P) H redox systems could be controlling oxidase activity. BPA generated similar to 60 - 80% more lucigenin (5 muM) chemiluminescence detectable superoxide than BCA. Apocynin (10 muM), a NAD(P) H oxidase inhibitor, and 6-aminonicotinamide (1 mM), a pentose phosphate inhibitor (PPP), both attenuated (approximately by 50 - 70%) superoxide detected in BPA and BCA. There was no significant difference in the expression of Nox2 or Nox4 mRNA or protein detected by Western blot analysis. NADPH and NADH increased superoxide in homogenates and isolated microsomal membrane fractions in a manner consistent with BPA and BCA having similar levels of oxidase activity. BPA had 4.2-fold higher levels of NADPH than BCA. The activity and protein levels of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting PPP enzyme generating cytosolic NADPH, were 1.5-fold higher in BPA than BCA. Thus BPA differ from BCA in that they have higher levels of G6PD activity, NADPH, and superoxide. Because both arteries have similar levels of Nox expression and activity, elevated levels of cytosolic NADPH may contribute to increased superoxide in BPA.