Preconditioning regulation of bcl-2 and p66shc by human NOS1 enhances tolerance to oxidative stress.
Preconditioning stress induced by a transient ischemia may increase brain tolerance to oxidative stress, and the underlying neuroprotective mechanisms are not well understood. In a series of experiments, we found that endogenous nitric oxide (NO), S-nitrosoglutathione (GSNO), and antioxidants blocked serum deprivation-induced oxidative stress and apoptosis in human neuroblastoma cells. Similar to nuclear redox factor-1 (Ref-1), mRNA of human neuronal nitric oxide synthase (hNOS1) was maximally up-regulated within 2 h after oxidative stress and down-regulated by NO/GSNO and hydroxyl radical (OH) scavenger. A brief preconditioning stress induced by serum deprivation for 2 h caused a delayed increase in the expression of hNOS1 protein and the associated formation of NO and cGMP, which in turn decreased OH generation and stress-related cell death. In addition to inhibiting caspase-3 through a dithiothreitol-sensitive S-nitrosylation process, preconditioning stress concomitantly up-regulated the expression of the anti-apoptotic bcl-2 protein and down-regulated the p66shc adaptor protein. This beneficial cytoprotective process of preconditioning stress is mediated by newly synthesized NO because it can be suppressed by the inhibition of hNOS1 and guanylyl cyclase. Therefore, the constitutive isoform of hNOS1 is dynamically redox-regulated to meet both functional and compensatory demands of NO for gene regulation, antioxidant defense, and tolerance to oxidative stress.
Andoh
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National Institute of Mental Health, NIH Clinical Center 10/3D-41, Bethesda, MD 20892-1264, USA.
Lee
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Chiueh
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D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D018384:Oxidative Stress; D011506:Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D016895:Culture Media, Serum-Free; D005609:Free Radicals; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D009569:Nitric Oxide; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I