NO-induced oxidative stress and glutathione metabolism in rodent and human cells
NO-induced oxidative stress and glutathione metabolism in rodent and human cells
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DOI：
10.1016/0891-5849(96)00219-5
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发表时间：
1996-01-01
影响因子：
7.4
通讯作者：
Tannenbaum, SR
中科院分区：
文献类型：
--
作者：
Luperchio, S;Tamir, S;Tannenbaum, SR
一氧化氮（NO）是一种由许多类型的细胞产生的自由基物质，已知在调节过程和细胞防御中起关键作用，但它也可能参与附带反应，导致NO产生细胞和邻近细胞中的DNA损伤和细胞死亡。已证明谷氨酸可保护细胞免受自由基和活性氧的毒性作用。本研究的目的是调查谷胱甘肽代谢的差异是否可以解释对NO杀伤细胞的抗性或敏感性。NO的细胞毒作用。在CHO-AA 8（中国人卵巢）细胞和TK 6（人淋巴母细胞）细胞中检测了用L-丁硫氨酸SR-亚砜亚胺（SO）（一种有效的γ-谷氨酰半胱氨酸合成酶抑制剂）和1，3-双-（2-氯乙基）-1-亚硝基脲（BCNU）（一种不可逆的谷胱甘肽还原酶抑制剂）预处理的细胞。谷胱甘肽水平的耗尽和氧化还原的逮捕所造成的后果，使我们能够显示参与谷胱甘肽保护细胞从NO和调查的重要性，谷胱甘肽代谢的变化对NO诱导的毒性。在CHO-AA 8细胞中，我们发现用NO处理导致还原型谷胱甘肽（GSH）氧化为氧化型谷胱甘肽（GSSG）和混合型谷胱甘肽二硫化物（GSSR）。由此产生的GSH耗竭刺激其从头合成，使细胞能够抵抗NO的杀伤。在TK 6细胞中观察到GSH代谢的轻微差异。NO导致GSSG水平升高，与在CHO-AA 8细胞中观察到的相似，然而，还发现GSH水平降低，GSSR水平没有变化，并且毒性水平更高，这表明NO处理的TK 6细胞不如CHO细胞那样能够保持GSH稳态。我们的结论是，GSH参与保护细胞免受NO的杀伤，并且GSH的从头合成和GSSG的减少在维持足够的细胞保护水平中是重要的。
Nitric oxide (NO), a radical species produced by many types of cells, is known to play a critical role in both regulatory processes and cell defense, yet it may also participate in collateral reactions, leading to DNA damage and cell death in both NO-generating and neighboring cells. Glutathione has been shown to protect cells from the toxic effects of free radicals and reactive oxygen species. The goal of this study was to investigate whether differences in glutathione metabolism could account for the resistance or sensitivity to cell killing by NO .. The cytotoxic effect of NO . was examined in CHO-AA8 (Chinese Hamster Ovary)cells and TK6 (human lymphoblastoid) cells pretreated with L-buthionine SR-sulfoximine (SO), a potent inhibitor of gamma-glutamylcysteine synthetase, and with 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU), an irreversible inhibitor of glutathione reductase. The consequences resulting from the depletion of glutathione levels and from the arrest of oxidoreduction allowed us to show the involvement of glutathione in protecting cells from NO and to investigate the importance of changes in glutathione metabolism on NO-induced toxicity. In CHO-AA8 cells, we found that treatment with NO resulted in the oxidation of reduced glutathione (GSH) to oxidized glutathione (GSSG) and to mixed glutathione disulfides (GSSR). The resulting depletion of GSH stimulated its de novo synthesis, enabling the cells to resist killing by NO. A slight difference in GSH metabolism was observed in TK6 cells. NO led to an increase in GSSG levels similar to that observed in CHO-AA8 cells, however, a decrease in GSH levels, no change in GSSR levels, and higher levels of toxicity were also found, suggesting that NO-treated TK6 cells are not as competent in GSH homeostasis as CHO cells. We conclude that GSH is involved in protecting cells from killing by NO and that both de novo synthesis of GSH and GSSG reduction are important in maintaining an adequate level of protection for the cells.