Protein Sulfenylation: A Novel Readout of Environmental Oxidant Stress

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• 作者：Phillip A. Wages ; Katelyn S. Lavrich ; Zhenfa Zhang ; Wan-Yun Cheng ; Elizabeth Corteselli ; Avram Gold ; Philip Bromberg ; Steven O. Simmons ; James M. Samet
• 刊名：Chemical Research in Toxicology
• 出版年：2015
• 出版时间：December 21, 2015
• 年：2015
• 卷：28
• 期：12
• 页码：2411-2418
• 全文大小：432K
• ISSN：1520-5010

文摘

Oxidative stress is a commonly cited mechanism of toxicity of environmental agents. Ubiquitous environmental chemicals such as the diesel exhaust component 1,2-naphthoquinone (1,2-NQ) induce oxidative stress by redox cycling, which generates hydrogen peroxide (H₂O₂). Cysteinyl thiolate residues on regulatory proteins are subjected to oxidative modification by H₂O₂ in physiological contexts and are also toxicological targets of oxidant stress induced by environmental contaminants. We investigated whether exposure to environmentally relevant concentrations of 1,2-NQ can induce H₂O₂-dependent oxidation of cysteinyl thiols in regulatory proteins as a readout of oxidant stress in human airway epithelial cells. BEAS-2B cells were exposed to 0鈥?000 渭M 1,2-NQ for 0鈥?0 min, and levels of H₂O₂ were measured by ratiometric spectrofluorometry of HyPer. H₂O₂-dependent protein sulfenylation was measured using immunohistochemistry, immunoblotting, and isotopic mass spectrometry. Catalase overexpression was used to investigate the relationship between H₂O₂ generation and protein sulfenylation in cells exposed to 1,2-NQ. Multiple experimental approaches showed that exposure to 1,2-NQ at concentrations as low as 3 渭M induces H₂O₂-dependent protein sulfenylation in BEAS-2B cells. Moreover, the time of onset and duration of 1,2-NQ-induced sulfenylation of the regulatory proteins GAPDH and PTP1B showed significant differences. Oxidative modification of regulatory cysteinyl thiols in human lung cells exposed to relevant concentrations of an ambient air contaminant represents a novel marker of oxidative environmental stress.