Mild thermotolerance induced at 40°C protects HeLa cells against activation of death receptor-mediated apoptosis by hydrogen peroxide.
Preexposure to mild temperatures such as 40°C induces thermotolerance, whereby cells resist subsequent exposure to a toxic insult. This study investigates the protective effect of mild thermotolerance (3h, 40°C) against activation of death receptor-mediated apoptosis by H(2)O(2) in HeLa cells. H(2)O(2) (5-50μM) caused rapid activation (1-3h) of the Fas death receptor pathway of apoptosis, which was evident by up-regulation of the death ligand FasL and recruitment of the adaptor protein Fas-associated death domain to the plasma membrane. This resulted in activation of caspase-8 and caspase-2, which led to activation of the cross-talk pathway involving Bid cleavage, t-Bid translocation to mitochondria, and caspase-9 activation. These changes were all diminished in thermotolerant cells. Mild thermotolerance also protected cells against cytotoxicity from H(2)O(2) as well as execution-phase events of apoptosis such as caspase-3 activation and chromatin condensation. The antioxidant polyethylene glycol-catalase abolished FasL induction and caspase-8 activation due to H(2)O(2). FasL up-regulation; activation of caspases-8, -2, -9, and -3; and chromatin condensation were decreased by the p53 inhibitor pifithrin-α, implicating p53 as an upstream factor in the activation of death receptor-mediated apoptosis by H(2)O(2). This study advances knowledge about the protective effect of adaptive responses induced by mild stresses, such as fever temperatures, against induction of apoptosis by oxidative stress.
Département des sciences biologiques and TOXEN, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada.
Pragathi
P
Pallepati
Diana A
DA
Averill-Bates
D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D052160:Benzothiazoles / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D002374:Catalase / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D053222:Fas Ligand Protein / Q000235:genetics / Q000378:metabolism; D053200:Fas-Associated Death Domain Protein / Q000378:metabolism; D005434:Flow Cytometry; D016158:Genes, p53; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000633:toxicity*; D008928:Mitochondria / Q000378:metabolism; D018384:Oxidative Stress; D011092:Polyethylene Glycols / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000494:pharmacology; D053218:Receptors, Death Domain / Q000378:metabolism*; D013696:Temperature; D014050:Toluene / Q000031:analogs & derivatives / Q000494:pharmacology; D019014:fas Receptor / Q000378:metabolism
D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D052160:Benzothiazoles; D002843:Chromatin; C505533:FADD protein, human; C491901:FAS protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D053200:Fas-Associated Death Domain Protein; D017382:Reactive Oxygen Species; D053218:Receptors, Death Domain; C070295:catalase-polyethylene glycol; D019014:fas Receptor; D014050:Toluene; D011092:Polyethylene Glycols; D006861:Hydrogen Peroxide; C121565:pifithrin; D002374:Catalase; D020169:Caspases