Mitochondrial Electron Transport Chain-Derived Superoxide Exits Macrophages: Implications for Mononuclear Cell-Mediated Pathophysiological Processes.
Mitochondrial Electron Transport Chain-Derived Superoxide Exits Macrophages: Implications for Mononuclear Cell-Mediated Pathophysiological Processes.
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线粒体电子传输链衍生的超氧化物退出巨噬细胞：对单核细胞介导的病理生理过程的影响。
DOI：
10.20455/ros.2016.815
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Trush MA
中科院分区：
文献类型：
--
作者：
Li Y;Zhu H;Kuppusamy P;Zweier JL;Trush MA
线粒体电子传递链（METC）源性超氧阴离子自由基参与细胞原癌基因激活、促有丝分裂反应和肿瘤生长的研究近年来受到广泛关注。为了使METC衍生的超氧化物参与上述过程中的任何一个，它从线粒体中退出将是关键的一步。细胞内超氧化物的检测表明，线粒体呼吸是在未受刺激或静息的单核/巨噬细胞的细胞超氧化物的主要来源。然而，目前缺乏从线粒体中排出超氧化物的直接证据。在这里，我们表明，METC衍生的超氧化物确实从未受刺激的单核细胞/巨噬细胞的线粒体中退出。超氧化物的释放首先被发现发生在从这些细胞中分离的基质支持的线粒体中。我们还观察到细胞外超氧化物的存在与完整的未刺激/静息细胞。线粒体抑制剂鱼藤酮或解偶联剂羰基氰化物对三氟甲基苯腙可显著减少细胞外超氧化物（>90%）。此外，具有缺陷METC的细胞表现出胞外超氧化物的显著减少（>90%），表明对于完整细胞，METC衍生的超氧化物不仅从线粒体中存在，而且可以在细胞外释放。线粒体释放的超氧阴离子自由基可与外源性一氧化氮反应生成过氧亚硝基阴离子。线粒体来源的胞外超氧化物也能氧化低密度脂蛋白（LDL）。因此，这些结果解决了超氧化物从线粒体中退出的能力的任何不确定性。这项研究还首次确定了线粒体作为未受刺激的静息单核细胞/巨噬细胞中细胞外超氧化物的主要来源，这对这些单核细胞参与各种病理生理情况具有影响。
The involvement of mitochondrial electron transport chain (METC)-derived superoxide anion radical in cell protooncogene activation, mitogenic responses, and cancerous growth has recently received much attention. In order for METC-derived superoxide to participate in any of the above processes, its exit from mitochondria would be a critical step. Detection of intracellular superoxide showed that mitochondrial respiration is the major source of cellular superoxide in unstimulated or resting monocytes/macrophages. However, direct evidence for the exit of superoxide from mitochondria is presently lacking. Here we show that METC-derived superoxide does exit from mitochondria in unstimulated monocytes/macrophages. Release of superoxide was first found to occur with substrate-supported mitochondria isolated from these cells. We also observed the presence of extracellular superoxide with the intact unstimulated/resting cells. Extracellular superoxide was markedly diminished (>90%) by the mitochondrial inhibitor, rotenone, or the uncoupler, carbonylcyanide p-(trifluromethy) phenylhydrazone. Furthermore, cells with a deficient METC exhibited significant reduction (>90%) in extracellular superoxide, demonstrating that with intact cells METC-derived superoxide not only exits from mitochondria, but can be released extracellularly. Superoxide anion radical released from mitochondria could react with exogenous nitric oxide, forming peroxynitrite. Mitochondria-derived extracellular superoxide could also oxidize low-density lipoprotein (LDL). These results thus resolve any uncertainty on the ability of superoxide to exit from mitochondria. This study for the first time also identifies mitochondria as the major source of extracellular superoxide in unstimulated resting monocytes/macrophages, which has implications for the involvement of these mononuclear cells in various pathophysiological situations.