Nitric oxide-induced resistance to hydrogen peroxide stress is a glutamate cysteine ligase activity-dependent process.
Nitric oxide (*NO) is a reactive nitrogen species known to be involved in cytotoxic processes. Cells respond to cytotoxic injury by stress response induction leading to the development of cellular resistance. This report describes an *NO-induced stress response in Chinese hamster fibroblasts (HA1), which leads to glutathione synthesis-dependent resistance to H2O2-mediated oxidative stress. The development of resistance to H2O2 was completely abolished by the inhibition of glutamate cysteine ligase (GCL) during the first 8 h of recovery after *NO exposure. Altered thiol metabolism was observed immediately after *NO exposure as demonstrated by up to 75% decrease in intracellular thiol pools (glutathione, gamma-glutamylcysteine, and cysteine), which then reaccumulated during the *NO-mediated development of resistance. Immunoreactive protein and activity associated with GCL decreased immediately after exposure to *NO and then reaccumulated during the development of resistance to H2O2 challenge. Moreover, compared to N2 controls the activity levels of GCL in *NO-exposed cells increased approximately twofold 24 h after H2O2 challenge. These results demonstrate that *NO exposure is capable of inducing an adaptive response to H2O2-mediated oxidative stress in mammalian cells, which involves alterations in thiol metabolism and is dependent upon glutathione synthesis and increased GCL activity.
Ridnour
Lisa A
LA
Division of Radiation and Cancer Biology, Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park Boulevard, Room 411, St. Louis, MO 63108, USA. ridnourl@mail.nih.gov
Sim
Julia E
JE
Choi
Jinah
J
Dickinson
Dale A
DA
Forman
Henry J
HJ
Ahmad
Iman M
IM
Coleman
Mitchell C
MC
Hunt
Clayton R
CR
Goswami
Prahbat C
PC
Spitz
Douglas R
DR
D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005721:Glutamate-Cysteine Ligase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D009569:Nitric Oxide / Q000494:pharmacology*; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D013438:Sulfhydryl Compounds / Q000378:metabolism
D016166:Free Radical Scavengers; D016877:Oxidants; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione