Intracellular redox homeostasis in the airway epithelium is closely regulated through adaptive signaling and metabolic pathways. However, inhalational exposure to xenobiotic stressors such as secondary organic aerosols (SOA) can alter intracellular redox homeostasis. Isoprene hydroxy hydroperoxide (ISOPOOH), a ubiquitous volatile organic compound derived from the atmospheric photooxidation of biogenic isoprene, is a major contributor to SOA. We have previously demonstrated that exposure of human airway epithelial cells (HAEC) to ISOPOOH induces oxidative stress through multiple mechanisms including lipid peroxidation, glutathione oxidation, and alterations of glycolytic metabolism. Using dimedone-based reagents and copper catalyzed azo-alkynyl cycloaddition to tag intracellular protein thiol oxidation, we demonstrate that exposure of HAEC to micromolar levels of ISOPOOH induces reversible oxidation of cysteinyl thiols in multiple intracellular proteins, including GAPDH, that was accompanied by a dose-dependent loss of GAPDH enzymatic activity. These results demonstrate that ISOPOOH induces an oxidative modification of intracellular proteins that results in loss of GAPDH activity, which ultimately impacts the dynamic regulation of the intracellular redox homeostatic landscape in HAEC.

中文翻译：

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暴露于环境过氧化物的人气道上皮细胞中硫醇氧化介导的 GAPDH 抑制


气道上皮细胞内氧化还原稳态通过适应性信号传导和代谢途径受到密切调节。然而，吸入暴露于异生物质应激源（例如二次有机气溶胶（SOA））可能会改变细胞内氧化还原稳态。异戊二烯羟基过氧化氢 (ISOPOOH) 是一种普遍存在的挥发性有机化合物，源自生物异戊二烯的大气光氧化作用，是 SOA 的主要贡献者。我们之前已经证明，人气道上皮细胞（HAEC）暴露于 ISOPOOH 会通过多种机制诱导氧化应激，包括脂质过氧化、谷胱甘肽氧化和糖酵解代谢的改变。使用基于双甲酮的试剂和铜催化的偶氮炔基环加成来标记细胞内蛋白质硫醇氧化，我们证明将 HAEC 暴露于微摩尔水平的 ISOPOOH 会诱导多种细胞内蛋白质（包括 GAPDH）中半胱氨酰硫醇的可逆氧化，并伴随一定剂量的氧化。 GAPDH 酶活性的依赖性丧失。这些结果表明，ISOPOOH 会诱导细胞内蛋白质发生氧化修饰，导致 GAPDH 活性丧失，最终影响 HAEC 细胞内氧化还原稳态的动态调节。