Wu Jun, Xu Hu, Yang Min, Martin Claudio M, Kvietys Peter R, Rui Tao
Lawson Health Research Institute, Department of Medical Biophysics, University of Western Ontario, Canada.
Free Radic Biol Med. 2009 May 15;46(10):1338-45. doi: 10.1016/j.freeradbiomed.2009.02.012. Epub 2009 Feb 26.
It has been reported that polymorphonuclear leukocyte (PMN) infiltration into the myocardial interstitium is involved in sepsis-induced myocardial dysfunction. The aim of this study was to evaluate the role of NADPH oxidase in the sepsis-induced conversion of cardiomyocytes to a proinflammatory phenotype. Using an in vitro approach we evaluated the role of NADPH oxidase in cardiomyocyte CXC chemokine production and its ability to promote PMN transendothelial migration under septic conditions. Treatment of cardiac myocytes with septic plasma (1) activated NADPH oxidase (p47phox phosphorylation) and increased its activity (O(2)(-) production) and (2) converted them to a proinflammatory phenotype; both effects were prevented by blockade of NADPH oxidase. NF-kappaB nuclear translocation was increased in cardiomyocytes conditioned with septic plasma, a response prevented by blockade of NADPH oxidase. The increase in NF-kappaB activation/translocation was associated with phosphorylation of both IKK and the p65 subunit of NF-kappaB. Blockade of NADPH oxidase prevented phosphorylation of IKK, but not p65. Blockade approaches indicated that p38 MAP kinase (previously implicated in NF-kappaB activation) did not play a role in the NADPH oxidase pathway, either upstream or downstream. Collectively, the results of this study and those of previous reports indicate that the conversion of cardiomyocytes to a proinflammatory phenotype in sepsis involves two distinct pathways: NADPH oxidase-mediated phosphorylation of IKK and p38 MAP kinase-mediated phosphorylation of p65.
据报道，多形核白细胞（PMN）浸润至心肌间质与脓毒症诱导的心肌功能障碍有关。本研究的目的是评估NADPH氧化酶在脓毒症诱导的心肌细胞向促炎表型转化中的作用。我们采用体外方法评估了NADPH氧化酶在脓毒症条件下对心肌细胞CXC趋化因子产生的作用及其促进PMN跨内皮迁移的能力。用脓毒症血浆处理心肌细胞（1）激活了NADPH氧化酶（p47phox磷酸化）并增加了其活性（超氧阴离子生成），（2）使其转化为促炎表型；这两种效应均被NADPH氧化酶的阻断所抑制。在经脓毒症血浆处理的心肌细胞中，NF-κB核转位增加，这种反应被NADPH氧化酶的阻断所抑制。NF-κB激活/转位的增加与IKK和NF-κB的p65亚基的磷酸化有关。NADPH氧化酶的阻断可抑制IKK的磷酸化，但不能抑制p65的磷酸化。阻断方法表明，p38丝裂原活化蛋白激酶（先前认为与NF-κB激活有关）在NADPH氧化酶途径的上游或下游均不起作用。总体而言，本研究结果及先前报道结果表明，脓毒症中心肌细胞向促炎表型的转化涉及两条不同的途径：NADPH氧化酶介导的IKK磷酸化和p38丝裂原活化蛋白激酶介导的p65磷酸化。
