Glutathione peroxidase 1 and glutathione are required to protect mouse astrocytes from iron-mediated hydrogen peroxide toxicity.
The enzyme glutathione peroxidase 1 (GPx1) is involved in the cellular detoxification of peroxides. To test for the consequences of GPx deficiency in astrocytes, astrocyte-rich primary cultures from wild-type and GPx1-deficient [GPx1(-/-)] mice were exposed to H(2)O(2). In GPx1(-/-) astrocytes, the clearance rate of H(2)O(2) was slower than in wild-type cells. In contrast to GPx1-deficient astrocytes, wild-type cells exhibited, within 2 min of H(2)O(2) application, a rapid and transient accumulation of cellular glutathione disulfide that amounted to 60% of total glutathione. The peroxide treatment did not affect the viability of wild-type astrocytes, whereas 45% of the GPx1(-/-) cells died within 8 hr. However, the viability of both types of astrocytes was strongly compromised by lowering cellular glutathione content before peroxide application. In contrast, inactivation of catalase caused substantial cell death only in GPx1(-/-) cells but not in wild-type astrocytes. The cell death observed was prevented by the iron chelators deferoxamine, 1,10-phenathroline, or 2,2'-dipyridyl, whereas preincubation with ferric ammonium citrate increased the toxicity of peroxide treatments. These results demonstrate that GPx1 contributes to the rapid clearance of H(2)O(2) by mouse astrocytes and that both GPx1 and a high concentration of glutathione are required to protect these cells from iron-dependent peroxide damage.
Liddell
Jeff R
JR
School of Psychology, Psychiatry and Psychological Medicine, Monash University, Clayton, Victoria, Australia.
Hoepken
Hans H
HH
Crack
Peter J
PJ
Robinson
Stephen R
SR
Dringen
Ralf
R
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002374:Catalase / Q000037:antagonists & inhibitors / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology*; D015536:Down-Regulation / Q000235:genetics; D005290:Ferric Compounds / Q000633:toxicity; D016166:Free Radical Scavengers / Q000378:metabolism / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000633:toxicity; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000494:pharmacology; D008657:Metabolic Clearance Rate / Q000187:drug effects / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D000644:Quaternary Ammonium Compounds / Q000633:toxicity; D000094765:Glutathione Peroxidase GPX1
D005290:Ferric Compounds; D016166:Free Radical Scavengers; D005609:Free Radicals; D007502:Iron Chelating Agents; D000644:Quaternary Ammonium Compounds; D006861:Hydrogen Peroxide; D007501:Iron; D002374:Catalase; D005979:Glutathione Peroxidase; D005978:Glutathione; C013531:ferric ammonium citrate; D000094765:Glutathione Peroxidase GPX1; C000722068:Gpx1 protein, mouse