Su Y, Han W, Giraldo C, De Li Y, Block E R
Department of Medicine, University of Florida College of Medicine, and Medical Research Service of the Department of Veterans Affairs, Gainesville, Florida, USA.
Am J Respir Cell Mol Biol. 1998 Nov;19(5):819-25. doi: 10.1165/ajrcmb.19.5.3091.
Cigarette smoking is associated with impaired endothelium-dependent vasodilation and reduced nitric oxide (NO) in the exhaled air of smokers. To explore the mechanism for the impairment of NO-mediated vasodilation, we studied the effect of cigarette smoke extract (CSE) on NO synthase (eNOS) activity and content in pulmonary artery endothelial cells (PAEC). Incubation of PAEC with CSE resulted in a time- and dose-dependent decrease in eNOS activity. The inhibitory effect of CSE on eNOS activity was not reversible. Both gas-phase and particulate-phase extracts of CSE contributed to the inhibition of eNOS activity. The protein kinase c (PKC) inhibitors staurosporine and chelerythrine did not affect the CSE-induced inhibition of eNOS activity. Catalase, superoxide dismutase (SOD), vitamin C, vitamin E, glutathione, and dithiothreitol (DTT) also did not prevent the CSE-induced inhibition of eNOS activity, and incubation of PAEC with 3 mM nicotine did not change the activity of eNOS. Treatment of PAEC with CSE also caused a nonreversible, time-dependent decrease in eNOS protein content detected by Western blot analysis, and in eNOS messenger RNA (mRNA) detected by Northern blot analysis. Treatment of PAEC with CSE had no effect on cell protein or glutathione contents or on lactate dehydrogenase (LDH) release. These results indicate that exposure to CSE causes an irreversible inhibition of eNOS activity in PAEC, and suggest that the decreased activity is secondary to reduced eNOS protein mass and mRNA. The decrease in eNOS activity may contribute to the high risk of pulmonary and cardiovascular disease in cigarette smokers.
吸烟与内皮依赖性血管舒张受损以及吸烟者呼出气体中一氧化氮（NO）减少有关。为了探究NO介导的血管舒张受损的机制，我们研究了香烟烟雾提取物（CSE）对肺动脉内皮细胞（PAEC）中一氧化氮合酶（eNOS）活性和含量的影响。用CSE孵育PAEC导致eNOS活性呈时间和剂量依赖性降低。CSE对eNOS活性的抑制作用是不可逆的。CSE的气相和颗粒相提取物均导致eNOS活性受到抑制。蛋白激酶c（PKC）抑制剂星形孢菌素和白屈菜红碱并不影响CSE诱导的eNOS活性抑制。过氧化氢酶、超氧化物歧化酶（SOD）、维生素C、维生素E、谷胱甘肽和二硫苏糖醇（DTT）也不能阻止CSE诱导的eNOS活性抑制，并且用3 mM尼古丁孵育PAEC不会改变eNOS的活性。用CSE处理PAEC还导致通过蛋白质印迹分析检测到的eNOS蛋白含量以及通过Northern印迹分析检测到的eNOS信使核糖核酸（mRNA）呈不可逆的、时间依赖性降低。用CSE处理PAEC对细胞蛋白质或谷胱甘肽含量或乳酸脱氢酶（LDH）释放没有影响。这些结果表明，暴露于CSE会导致PAEC中eNOS活性受到不可逆抑制，并提示活性降低继发于eNOS蛋白量和mRNA减少。eNOS活性降低可能是吸烟者肺部和心血管疾病高风险的原因之一。
