title: Glutathione and p53 independently mediate responses against oxidative stress in ES cells.
abstract: We have investigated the roles of the antioxidant glutathione and p53 in the response of embryonic stem (ES) cells to oxidative stress. ES cells express gammaGCS, a critical enzyme in glutathione (GSH) biosynthesis. Treatment with the pro-oxidant menadione led to elevation of GSH, a strong apoptotic response and reduced clonogenic survival. Addition of BSO, a specific gammaGCS inhibitor depleted GSH pools and prevented the menadione-induced increase in GSH, sensitizing cells to oxidative insult. Although p53 status had no bearing on either the basal levels of GSH or the menadione-induced GSH response, the levels of menadione-induced apoptosis were reduced in the absence of p53. We conclude that the pathways involving p53 and GSH act independently to protect against the deleterious effects of oxidative damage. Furthermore, the presence of an intact p53 pathway confers a long-term growth advantage post oxidative stress. Thus, in the absence of p53 ES cells bearing genotoxic damage are less likely to be propagated, suggesting that p53-dependent apoptosis acts to limit the deleterious effects of oxidative stress during early development.
authors.affiliation: CRC Laboratories, Department of Pathology, University of Edinburgh, Edinburgh, UK.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Coe
authors.forename: Irfan
authors.initials: I
authors.lastname: Rahman
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sphyris
authors.forename: Alan R
authors.initials: AR
authors.lastname: Clarke
authors.forename: David J
authors.initials: DJ
authors.lastname: Harrison
mesh_terms: D000818:Animals; D000933:Antifibrinolytic Agents; D017209:Apoptosis; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003114:Colony-Forming Units Assay; D004622:Embryo, Mammalian / Q000166:cytology; D005609:Free Radicals / Q000378:metabolism; D005721:Glutamate-Cysteine Ligase / Q000096:biosynthesis / Q000235:genetics; D005978:Glutathione / Q000378:metabolism*; D051379:Mice; D018384:Oxidative Stress / Q000502:physiology*; D015398:Signal Transduction; D013234:Stem Cells / Q000187:drug effects / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000378:metabolism*; D024483:Vitamin K 3 / Q000494:pharmacology
chemical_list: D000933:Antifibrinolytic Agents; D005609:Free Radicals; D016159:Tumor Suppressor Protein p53; D024483:Vitamin K 3; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione