Merad-Boudia M, Nicole A, Santiard-Baron D, Saillé C, Ceballos-Picot I
CNRS URA 1335, CHU Necker-Enfants Malades, Paris, France.
Biochem Pharmacol. 1998 Sep 1;56(5):645-55. doi: 10.1016/s0006-2952(97)00647-3.
In Parkinson's disease (PD), dopaminergic cell death in the substantia nigra was associated with a profound glutathione (GSH) decrease and a mitochondrial dysfunction. The fall in GSH concentration seemed to appear before the mitochondrial impairment and the cellular death, suggesting that a link may exist between these events. The relationships between GSH depletion, reactive oxygen species (ROS) production, mitochondrial dysfunction and the mode of cell death in neuronal cells remain to be resolved and will provide important insights into the etiology of Parkinson's disease. An approach to determine the role of GSH in the mitochondrial function and in neurodegeneration was to create a selective depletion of GSH in a neuronal cell line in culture (NS20Y) by inhibiting its biosynthesis with L-buthionine-(S,R)-sulfoximine (BSO), a specific inhibitor of gamma-glutamylcysteine synthetase. This treatment led to a nearly complete GSH depletion after 24 hr and induced cellular death via an apoptotic pathway after 5 days of BSO treatment. By using the reactive oxygen species-sensitive probe 2',7'-dichlorofluorescin, we observed that the rapid GSH depletion was accompanied, early in the process, by a strong and transient intracellular increase in reactive oxygen species evidenced after 1 hr with BSO, culminating after 3 hr when the GSH level decreased to 30% of normal. GSH depletion induced a loss of mitochondrial function after 48 hr of BSO treatment. In particular, the activities of complexes I, II and IV of the respiratory chain were decreased by 32, 70 and 65%, respectively as compared to controls. These results showed the crucial role of GSH for maintaining the integrity of mitochondrial function in neuronal cells. Oxidative stress and mitochondrial impairment, preceding DNA fragmentation, could be early events in the apoptotic process induced by GSH depletion. Our data are consistent with the hypothesis that GSH depletion could contribute to neuronal apoptosis in Parkinson's disease through oxidative stress and mitochondrial dysfunction.
在帕金森病（PD）中，黑质中的多巴胺能细胞死亡与谷胱甘肽（GSH）显著减少及线粒体功能障碍有关。GSH浓度的下降似乎出现在线粒体损伤和细胞死亡之前，这表明这些事件之间可能存在联系。GSH耗竭、活性氧（ROS）产生、线粒体功能障碍与神经元细胞死亡方式之间的关系仍有待解决，这将为帕金森病的病因学提供重要见解。一种确定GSH在神经元细胞线粒体功能和神经退行性变中作用的方法是，通过用γ-谷氨酰半胱氨酸合成酶的特异性抑制剂L-丁硫氨酸-（S，R）-亚砜胺（BSO）抑制其生物合成，在培养的神经元细胞系（NS20Y）中选择性耗竭GSH。这种处理在24小时后导致GSH几乎完全耗竭，并在BSO处理5天后通过凋亡途径诱导细胞死亡。通过使用活性氧敏感探针2'，7'-二氯荧光素，我们观察到，在该过程早期，快速的GSH耗竭伴随着活性氧在细胞内强烈且短暂的增加，在使用BSO 1小时后即可证明，在3小时达到峰值时GSH水平降至正常水平的30%。BSO处理48小时后，GSH耗竭导致线粒体功能丧失。特别是与对照组相比，呼吸链复合体I、II和IV的活性分别降低了32%、70%和65%。这些结果表明GSH对于维持神经元细胞线粒体功能的完整性至关重要。氧化应激和线粒体损伤先于DNA片段化出现可能是GSH耗竭诱导的凋亡过程中的早期事件。我们的数据与以下假设一致，即GSH耗竭可能通过氧化应激和线粒体功能障碍导致帕金森病中的神经元凋亡。
