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Glutathione peroxidase 1 and a high cellular glutathione concentration are essential for effective organic hydroperoxide detoxification in astrocytes
Author(s) -
Liddell Jeff R.,
Dringen Ralf,
Crack Peter J.,
Robinson Stephen R.
Publication year - 2006
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.20433
Subject(s) - cumene hydroperoxide , glutathione , gpx1 , buthionine sulfoximine , biochemistry , glutathione peroxidase , incubation , toxicity , biology , lipid peroxidation , catalase , astrocyte , gpx4 , neuroglia , antioxidant , chemistry , microbiology and biotechnology , endocrinology , enzyme , organic chemistry , central nervous system , catalysis
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 μM 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. © 2006Wiley‐Liss, Inc.