Mitochondrial glutathione depletion reveals a novel role for the pyruvate dehydrogenase complex as a key H2O2-emitting source under conditions of nutrient overload
Mitochondrial glutathione depletion reveals a novel role for the pyruvate dehydrogenase complex as a key H2O2-emitting source under conditions of nutrient overload
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DOI：
10.1016/j.freeradbiomed.2013.09.008
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发表时间：
2013-12-01
影响因子：
7.4
通讯作者：
Neufer, P. Darrell
中科院分区：
文献类型：
--
作者：
Fisher-Wellman, Kelsey H.;Gilliam, Laura A. A.;Neufer, P. Darrell
超氧化物/H2 O2的产生曾经被认为是有氧代谢的“副产品”，现在被理解为是一个高度专业化和广泛调节的过程，负责对大量含巯基蛋白质施加控制，统称为氧化还原敏感蛋白质组。尽管继发于过氧化物暴露升高的该过程中的中断与疾病有关，但调节过氧化物负荷增加的来源和机制仍然定义不清，因此难以使用药物治疗靶向。在这里，我们确定了丙酮酸脱氢酶复合物（PDC）作为一个关键来源的H2 O2在骨骼肌线粒体的条件下抑郁谷胱甘肽氧化还原缓冲完整性。用不同浓度的谷胱甘肽耗竭剂1-氯-2，4-二硝基苯处理透化肌纤维，导致三羟甲基丙酸盐支持的JH（2）O（2）排放（H2 O2从线粒体基质扩散到周围测定介质中的通量）呈剂量依赖性增加，排放率最终上升至超过所有测试底物组合。在从多个物种制备的透化纤维中观察到这种对谷胱甘肽耗尽的惊人敏感性，并且对PDC是特异性的。啮齿类动物在高脂喂养后细胞谷胱甘肽池的生理氧化被发现会提高PDC JH（2）O（2）的排放，以及增加复合物对GSH消耗的敏感性。这些发现揭示PDC作为H2 O2生产的潜在主要位点，其对线粒体谷胱甘肽氧化还原状态极其敏感。爱思唯尔公司出版
Once regarded as a "by-product" of aerobic metabolism, the production of superoxide/H2O2 is now understood to be a highly specialized and extensively regulated process responsible for exerting control over a vast number of thiol-containing proteins, collectively referred to as the redox-sensitive proteome. Although disruptions within this process, secondary to elevated peroxide exposure, have been linked to disease, the sources and mechanisms regulating increased peroxide burden remain poorly defined and as such are difficult to target using pharmacotherapy. Here we identify the pyruvate dehydrogenase complex (PDC) as a key source of H2O2 within skeletal muscle mitochondria under conditions of depressed glutathione redox buffering integrity. Treatment of permeabilized myofibers with varying concentrations of the glutathione-depleting agent 1-chloro-2,4-dinitrobenzene led to a dose-dependent increase in pyruvate-supported JH(2)O(2) emission (the flux of H2O2 diffusing out of the mitochondrial matrix into the surrounding assay medium), with emission rates eventually rising to exceed those of all substrate combinations tested. This striking sensitivity to glutathione depletion was observed in permeabilized fibers prepared from multiple species and was specific to PDC. Physiological oxidation of the cellular glutathione pool after high-fat feeding in rodents was found to elevate PDC JH(2)O(2) emission, as well as increasing the sensitivity of the complex to GSH depletion. These findings reveal PDC as a potential major site of H2O2 production that is extremely sensitive to mitochondrial glutathione redox status. Published by Elsevier Inc.