title: Induction of glutathione peroxidase in response to inactivation by nitric oxide.
abstract: To determine effect of nitric oxide (NO) on cellular glutathione peroxidase (GPX) level in living cells, we measured the activity, protein and mRNA of GPX in rat kidney (KNRK) cells under a high NO condition. Combined treatment of lipopolysaccharide (LPS, 1 microgram/ml) and tumor necrosis factor-alpha (TNF-alpha, 50 ng/ml) synergistically enhanced (23-folds) nitrite production from KNRK cells. This was suppressed by an inducible NO synthase (iNOS) inhibitor (aminoguanidine, N-nitro-L-arginine methylester hydrochloride) and arginase. iNOS expression was detected by RT-PCR in the treated cells. GPX was inactivated irreversibly when the cells had been homogenized before exposure to a NO donor, S-nitroso-N-acetylpenicillamine (SNAP). In living KNRK cells, SNAP and LPS + TNF-alpha exerted a transient effect on the GPX activity. The treatment with SNAP (200 microM) or sodium nitroprusside (200 microM) enhanced GPX gene expression, which was blocked by a NO scavenger, 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl-3-oxide. GPX mRNA was markedly increased by the treatment with LPS + TNF-alpha, and aminoguanidine blocked the effect. In cells metabolically labeled with 75Se, LPS + TNF-alpha accelerated the incorporation of radioactivity into GPX molecule by 2.1-fold. These results suggest that inactivation of GPX by NO triggers a signal for inducing GPX gene expression in KNRK cells, thereby restoring the intracellular level of this indispensable enzyme.
authors.affiliation: Department of Pediatrics, Yamanashi Medical University, Yamanashi, 409-3898 Japan. kdobashi@res.yamanashi-med.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Dobashi
authors.forename: K
authors.initials: K
authors.lastname: Asayama
authors.forename: T
authors.initials: T
authors.lastname: Nakane
authors.forename: K
authors.initials: K
authors.lastname: Kodera
authors.forename: H
authors.initials: H
authors.lastname: Hayashibe
authors.forename: S
authors.initials: S
authors.lastname: Nakazawa
mesh_terms: D000818:Animals; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005979:Glutathione Peroxidase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology; D008070:Lipopolysaccharides / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D020030:Nitric Oxide Donors; D012333:RNA, Messenger; C110881:S-nitro-N-acetylpenicillamine; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D005979:Glutathione Peroxidase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D010396:Penicillamine