title: Glutathione peroxidase 1 and a high cellular glutathione concentration are essential for effective organic hydroperoxide detoxification in astrocytes.
abstract: Organic hydroperoxides are produced in the eicosanoid metabolism and by lipid peroxidation. To examine the contribution of glutathione peroxidase-1 (GPx1) and glutathione (GSH) in the disposal of organic hydroperoxides in brain astrocytes, primary astrocyte cultures from wild type or GPx1-deficient (GPx1(-/-)) mice were exposed to cumene hydroperoxide (CHP). After application of 100 microM CHP, the peroxide disappeared quickly from the incubation medium of wild type cells with a half-life of 9 min, whereas CHP clearance was strongly retarded in GPx1(-/-) astrocytes. Depletion of GSH by pre-incubation with buthionine sulfoximine (BSO) significantly slowed CHP clearance by wild type astrocytes, while almost completely preventing peroxide disposal by GPx1(-/-) cells. In contrast, the catalase inhibitor 3-aminotriazole (3AT) had no effect on CHP clearance. Application of CHP to wild type astrocytes was followed by a rapid and transient accumulation of GSSG, whereas in GPx1(-/-) cells no increase in the GSSG content was detected. Astrocytes from both mouse lines remained viable for up to 24 h following CHP exposure, however depletion of cellular GSH by pre-treatment with BSO compromised the viability of astrocytes, an effect that was stronger in GPx1(-/-) than in wild type cells. This cell death was almost completely prevented by iron chelators, whereas pre-incubation with iron increased CHP toxicity. These novel data demonstrate that the toxicity of organic hydroperoxides in astrocytes is iron-mediated, and that an intact GSH system is required for the effective removal of organic hydroperoxides and for protection from these peroxides.
authors.affiliation: School of Psychology, Psychiatry, and Psychological Medicine, Monash University, Clayton, Victoria, Australia. jeff.liddell@med.monash.edu.au
authors.forename: Jeff R
authors.initials: JR
authors.lastname: Liddell
authors.forename: Ralf
authors.initials: R
authors.lastname: Dringen
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Crack
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Robinson
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001555:Benzene Derivatives / Q000494:pharmacology; D001921:Brain / Q000378:metabolism*; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000235:genetics*; D007501:Iron / Q000378:metabolism / Q000633:toxicity; D007502:Iron Chelating Agents / Q000494:pharmacology; D008054:Lipid Peroxides / Q000378:metabolism*; D008657:Metabolic Clearance Rate / Q000187:drug effects / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D000094765:Glutathione Peroxidase GPX1
chemical_list: D001555:Benzene Derivatives; D004791:Enzyme Inhibitors; D007502:Iron Chelating Agents; D008054:Lipid Peroxides; D016877:Oxidants; D017382:Reactive Oxygen Species; D019328:Buthionine Sulfoximine; D007501:Iron; D005979:Glutathione Peroxidase; D005978:Glutathione; C007164:cumene hydroperoxide; D000094765:Glutathione Peroxidase GPX1; C000722068:Gpx1 protein, mouse