Interleukin-1-induced nitric oxide production modulates glutathione synthesis in cultured rat hepatocytes
Interleukin-1-induced nitric oxide production modulates glutathione synthesis in cultured rat hepatocytes
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DOI：
10.1152/ajpcell.1996.271.3.c851
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发表时间：
1996-09-01
影响因子：
5.5
通讯作者：
Schroeder, RA
中科院分区：
文献类型：
--
作者：
Kuo, PC;Abe, KY;Schroeder, RA
在培养的大鼠肝细胞中，我们之前已经证明，在毒素介导的氧化损伤中，白细胞介素-1 （IL-1）介导的一氧化氮（NO）合成的抑制与细胞内还原性谷胱甘肽（GSH）的消耗有关。为了进一步研究NO对大鼠肝细胞GSH代谢的影响，在半胱氨酸、胱氨酸和蛋氨酸摄取的背景下，研究了il -1介导的NO合成；2) γ -谷氨酰半胱氨酸合成酶、谷胱甘肽合成限速酶、谷胱甘肽还原酶和谷胱甘肽过氧化物酶的基因转录和酶活性；3)谷胱甘肽和氧化谷胱甘肽（GSSG）水平。抑制NO合成降低了GSH含量和GSH/GSSG比例，其方式不依赖于胍基环化酶。γ -谷氨酰半胱氨酸合成酶的酶活性和mRNA的稳态水平也受到抑制。核运行分析显示γ -谷氨酰半胱氨酸合成酶基因转录的消融。肝细胞对半胱氨酸、胱氨酸和蛋氨酸的摄取没有改变。谷胱甘肽还原酶和谷胱甘肽过氧化物酶的活性和稳态mRNA水平不受影响。这些结果表明，il -1介导的NO合成通过一种依赖于GSH合成限速酶转录调节的机制来调节肝细胞GSH合成。在氧化应激和IL-1暴露的情况下，肝细胞NO的合成可能通过调节GSH的合成而起到保护作用。
In cultured rat hepatocytes, we have previously demonstrated that inhibition of interleukin-1 (IL-1)-mediated nitric oxide (NO) synthesis is associated with depletion of intracellular reduced glutathione (GSH) in toxin-mediated oxidative injury. To further examine NO's effects on GSH metabolism in rat hepatocytes, IL-1-mediated NO synthesis was examined in the context of 1) cysteine, cystine, and methionine uptake; 2) gene transcription and enzyme activities for gamma-glutamylcysteine synthetase, the rate-limiting enzyme in GSH synthesis, glutathione reductase, and glutathione peroxidase; and 3) GSH and oxidized glutathione (GSSG) levels. Inhibition of NO synthesis decreased the GSH content and GSH/GSSG ratio in a guanylyl cyclase-independent fashion. Enzyme activity and steady-state levels of mRNA for gamma-glutamylcysteine synthetase were also depressed. Nuclear run-on analysis demonstrated ablation of gamma-glutamylcysteine synthetase gene transcription. Hepatocellular uptake of cysteine, cystine, and methionine was not altered. Activity and steady-state mRNA levels for glutathione reductase and glutathione peroxidase were not affected. These results indicate that IL-1-mediated NO synthesis regulates hepatocyte GSH synthesis through a mechanism that is dependent on transcriptional regulation of the rate-limiting enzyme in GSH synthesis. In the setting of oxidative stress and IL-1 exposure, hepatocyte synthesis of NO may be protective through regulation of GSH synthesis.