Cigarette Smoke Targets Glutaredoxin 1, Increasing S-Glutathionylation and Epithelial Cell Death
Cigarette Smoke Targets Glutaredoxin 1, Increasing S-Glutathionylation and Epithelial Cell Death
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DOI：
10.1165/rcmb.2010-0249oc
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发表时间：
2011-11-01
影响因子：
6.4
通讯作者：
Reynaert, Niki L.
中科院分区：
文献类型：
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作者：
Kuipers, Ine;Guala, Amy S.;Reynaert, Niki L.
众所周知，香烟烟雾（CS）会导致肺上皮细胞发生不可逆的氧化，并可能导致其死亡。然而，它对可逆和生理相关的氧化还原依赖性蛋白质修饰的影响仍有待研究。谷胱甘肽是一种重要的抗氧化剂，可以直接清除吸入的活性氧，但它也可以在轻度氧化应激下与蛋白质硫醇共价结合，以保护它们免受不可逆氧化。这种翻译后修饰称为 S-谷胱甘肽化，在生理条件下可被谷氧还蛋白 1 (Grx1) 酶逆转。本研究的目的是调查 CS 是否修饰 Grx1，以及这是否对蛋白质 S-谷胱甘肽化和上皮细胞死亡产生影响。将肺泡上皮细胞暴露于 CS 提取物 (CSE) 后，观察到 Grx1 mRNA 和蛋白质表达减少，同时活性降低，蛋白质 S-谷胱甘肽化增加。使用质谱法，证明了 CSE 和丙烯醛对重组 Grx1 的不可逆氧化，这与酶活性减弱有关。此外，暴露于 CSE 后，上皮细胞中的 Grx1 发生羰基化。 Grx1 的过度表达减弱了 CSE 诱导的蛋白质 S-谷胱甘肽化的增加并增加了存活率。相反，缺乏Grx1的小鼠的原代气管上皮细胞对CS诱导的细胞死亡更敏感，蛋白质S-谷胱甘肽化相应增加。这些结果表明CS不仅可以在表达水平上调节Grx1，还可以直接修饰Grx1本身，降低其活性。这些发现证明了 Grx1/S-谷胱甘肽氧化还原系统在 CS 诱导的肺上皮细胞死亡中的作用。
It is established that cigarette smoke (CS) causes irreversible oxidations in lung epithelial cells, and can lead to their death. However, its impact on reversible and physiologically relevant redox-dependent protein modifications remains to be investigated. Glutathione is an important antioxidant against inhaled reactive oxygen species as a direct scavenger, but it can also covalently bind protein thiols upon mild oxidative stress to protect them against irreversible oxidation. This posttranslational modification, known as S-glutathionylation, can be reversed under physiological conditions by the enzyme, glutaredoxin 1 (Grx1). The aim of this study was to investigate if CS modifies Grx1, and if this impacts on protein S-glutathionylation and epithelial cell death. Upon exposure of alveolar epithelial cells to CS extract (CSE), a decrease in Grx1 mRNA and protein expression was observed, in conjunction with decreased activity and increased protein S-glutathionylation. Using mass spectrometry, irreversible oxidation of recombinant Grx1 by CSE and acrolein was demonstrated, which was associated with attenuated enzyme activity. Furthermore, carbonylation of Grx1 in epithelial cells after exposure to CSE was shown. Overexpression of Grx1 attenuated CSE-induced increases in protein S-glutathionylation and increased survival. Conversely, primary tracheal epithelial cells of mice lacking Grx1 were more sensitive to CS-induced cell death, with corresponding increases in protein S-glutathionylation. These results show that CS can modulate Grx1, not only at the expression level, but can also directly modify Grx1 itself, decreasing its activity. These findings demonstrate a role for the Grx1/S-glutathionylation redox system in CS-induced lung epithelial cell death.