title: The role of a formaldehyde dehydrogenase-glutathione pathway in protein S-nitrosation in mammalian cells.
abstract: Intracellular sulfhydryls, both protein and non-protein, are potential targets of nitric oxide-related species. S-Nitrosation of proteins can occur in vivo and can affect their activity. Metabolic pathways that regulate protein S-nitrosation are therefore likely to be biologically important. We now report that formaldehyde dehydrogenase, an enzyme that decomposes S-nitrosoglutathione, can indirectly regulate the level of cellular protein S-nitrosation. Nitrogen oxide donors induced high levels of protein S-nitrosation in HeLa cells and lower levels in Mutatect fibrosarcoma cells, as determined by Saville-Griess assay and Western-dot-blot analysis. Depletion of glutathione by treatment with buthionine sulfoximine markedly increased protein S-nitrosation in both cell lines. Glutathione depletion also increased cytokine-induced S-nitrosation in brain endothelial cells. Formaldehyde dehydrogenase activity was 2-fold higher in Mutatect than in HeLa cells. We downregulated formaldehyde dehydrogenase activity in Mutatect cells by stably expressing antisense RNA and short-interfering RNA. In these cells, both protein S-nitrosation and S-nitrosoglutathione levels were significantly enhanced after exposure to nitrogen oxide donors as compared to parental cells. Overall, a strong inverse correlation between total S-nitrosothiols and formaldehyde dehydrogenase activity was seen. Inhibition of glutathione reductase, the enzyme that converts oxidized to reduced glutathione, by dehydroepiandrosterone similarly increased protein S-nitrosation and S-nitrosoglutathione levels in both cell lines. Our results provide the first evidence that formaldehyde dehydrogenase-dependent decomposition of S-nitrosoglutathione plays a role in protecting against nitrogen oxide-mediated protein S-nitrosation. We propose that formaldehyde dehydrogenase and glutathione reductase participate in a glutathione-dependent metabolic cycle that decreases protein S-nitrosation following exposure of cells to nitric oxide.
authors.affiliation: Institute for Biological Sciences, National Research Council, Ottawa, Ont., Canada.
authors.forename: Arsalan S
authors.initials: AS
authors.lastname: Haqqani
authors.forename: Skyz K
authors.initials: SK
authors.lastname: Do
authors.forename: H Chaim
authors.initials: HC
authors.lastname: Birnboim
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000445:Aldehyde Oxidoreductases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D000818:Animals; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002478:Cells, Cultured; D003545:Cysteine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D003687:Dehydroepiandrosterone / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism* / Q000502:physiology; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D015538:Nitrosation / Q000187:drug effects; D011506:Proteins / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D026422:S-Nitrosoglutathione / Q000494:pharmacology*; D026403:S-Nitrosothiols / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D020030:Nitric Oxide Donors; D011506:Proteins; D034741:RNA, Small Interfering; D026403:S-Nitrosothiols; D009599:Nitroprusside; D009569:Nitric Oxide; D003687:Dehydroepiandrosterone; D019328:Buthionine Sulfoximine; C024940:S-nitroso-N-acetylcysteine; D026422:S-Nitrosoglutathione; C021315:S-nitrosocysteine; C020145:formaldehyde dehydrogenase (glutathione); D000445:Aldehyde Oxidoreductases; D005980:Glutathione Reductase; D005978:Glutathione; D003545:Cysteine; D000111:Acetylcysteine