Glutathione Redox State Regulates Mitochondrial Reactive Oxygen Production

• Published in: The Journal of biological chemistry 2005-07, Vol.280 (27), p.25305-25312
• Main Authors: Shen, Dongxiao, Dalton, Timothy P, Nebert, Daniel W, Shertzer, Howard G
• Format: Article
• Language: English
• Subjects: Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Cytosol - metabolism; Glutathione - metabolism; Glutathione Disulfide - metabolism; Hydrogen Peroxide - metabolism; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria - drug effects; Mitochondria - metabolism; Oxidation-Reduction; Polychlorinated Dibenzodioxins - pharmacology; Reactive Oxygen Species - metabolism; Receptors, Aryl Hydrocarbon - genetics; Teratogens - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M500095200

Oxidative stress induced by 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD; dioxin) is poorly understood. Following one dose of TCDD (5 μg/kg body weight), mitochondrial succinate-dependent production of superoxide and H 2 O 2 in mouse liver doubled at 7–28 days, then subsided by day 56; concomitantly, levels of GSH and GSSG increased in both cytosol and mitochondria. Cytosol displayed a typical oxidative stress response, consisting of diminished GSH relative to GSSG, decreased potential to reduce protein-SSG mixed disulfide bonds (type 1 thiol redox switch) or protein-SS-protein disulfide bonds (type 2 thiol redox switch), and a +10 mV change in GSSG/2GSH reduction potential. In contrast, mitochondria showed a rise in reduction state, consisting of increased GSH relative to GSSG, increases in type 1 and type 2 thiol redox switches, and a –25 mV change in GSSG/2GSH reduction potential. Comparing Ahr (–/–) knock-out and wild-type mice, we found that TCDD-induced thiol changes in both cytosol and mitochondria were dependent on the aromatic hydrocarbon receptor (AHR). GSH was rapidly taken up by mitochondria and stimulated succinate-dependent H 2 O 2 production. A linear dependence of H 2 O 2 productionon thereduction potential for GSSG/2GSH exists between –150 and –300 mV. The TCDD-stimulated increase in succinate-dependent and thiol-stimulated production of reactive oxygen paralleled a four-fold increase in formamidopyrimidine DNA N -glycosylase (FPG)-sensitive cleavage sites in mitochondrial DNA, compared with a two-fold increase in nuclear DNA. These results suggest that TCDD produces an AHR-dependent oxidative stress in mitochondria, with concomitant mitochondrial DNA damage mediated, at least in part, by an increase in the mitochondrial thiol reduction state.