title: Protein Sulfenylation: A Novel Readout of Environmental Oxidant Stress.
abstract: 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 0-1000 μM 1,2-NQ for 0-30 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 μM 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.
authors.affiliation: Curriculum in Toxicology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States.
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Wages
authors.affiliation: Curriculum in Toxicology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States.
authors.forename: Katelyn S
authors.initials: KS
authors.lastname: Lavrich
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7400, United States.
authors.forename: Zhenfa
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.
authors.forename: Wan-Yun
authors.initials: WY
authors.lastname: Cheng
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7400, United States.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Corteselli
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7400, United States.
authors.forename: Avram
authors.initials: A
authors.lastname: Gold
authors.affiliation: Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States.
authors.forename: Philip
authors.initials: P
authors.lastname: Bromberg
authors.affiliation: National Center for Computational Toxicology, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.
authors.forename: Steven O
authors.initials: SO
authors.lastname: Simmons
authors.affiliation: Curriculum in Toxicology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7310, United States.|Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency , Chapel Hill, North Carolina 27711, United States.
authors.forename: James M
authors.initials: JM
authors.lastname: Samet
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D008954:Models, Biological; D009285:Naphthoquinones / Q000633:toxicity; D018384:Oxidative Stress; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011506:Proteins / Q000737:chemistry* / Q000187:drug effects; D013434:Sulfenic Acids / Q000737:chemistry* / Q000633:toxicity
chemical_list: D009285:Naphthoquinones; D011506:Proteins; D013434:Sulfenic Acids; C040756:1,2-naphthoquinone