GAPDH inhibition mediated by thiol oxidation in human airway epithelial cells exposed to an environmental peroxide
Syed Masood,
Hye-Young H. Kim,
Edward R. Pennington,
Keri A. Tallman,
Ned A. Porter,
Philip A. Bromberg,
Rebecca L. Rice,
Avram Gold,
Zhenfa Zhang,
James M. Samet
Affiliations
Syed Masood
Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Hye-Young H. Kim
Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
Edward R. Pennington
Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA; Public Health and Integrated Toxicology Division, U.S. Environmental Protection Agency, Chapel Hill, NC, USA
Keri A. Tallman
Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
Ned A. Porter
Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
Philip A. Bromberg
Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Rebecca L. Rice
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Avram Gold
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Zhenfa Zhang
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
James M. Samet
Public Health and Integrated Toxicology Division, U.S. Environmental Protection Agency, Chapel Hill, NC, USA; Corresponding author. EPA Human Studies Facility Chapel Hill, NC 27514, USA.
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.
