title: Dual effect of nitric oxide donors on cyclooxygenase-2 expression in human mesangial cells.
abstract: Nitric oxide (NO) is emerging as a key regulator of gene expression, capable of playing either positive or negative roles. The results of this study indicate that NO exerts a dual effect on cyclooxygenase-2 (COX-2) expression in human mesangial cells (HMC). Treatment of HMC with NO synthase inhibitors attenuated interleukin-1beta (IL-1beta/tumor necrosis factor-alpha (TNF-alpha)-elicited COX-2 protein and mRNA expression, suggesting a positive role of endogenous NO on COX-2 induction. However, NO donors (sodium nitroprusside [SNP] and S-nitroso-N-acetylpenicillamine [SNAP]) amplified cytokine-elicited COX-2 expression at early time points of treatment (up to 8 h for mRNA and up to 24 h for protein expression), but were inhibitory at later times. Oligonucleotide decoy experiments confirmed the importance of nuclear factor kappaB (NF-kappaB) activation for COX-2 induction by IL-1beta/TNF-alpha. Treatment with N(G)-nitro-L-arginine methyl ester (L-NAME) did not affect initial activation of NF-kappaB by IL-1beta/TNF-alpha, but unveiled an inhibitory effect of NO generation on NF-kappaB activity after 4 h. In HMC supplemented with SNP, cytokine-induced NF-kappaB activation was potentiated at early times of induction (5 to 15 min), but inhibited at later times (1 to 4 h), suggesting a dual effect of NO donors on NF-kappaB activation. Interestingly, IkappaBalpha protein levels followed a reciprocal pattern of expression: IkappaBalpha levels were lower at early times of induction in NO donor-supplemented cells; however, after 1 h of treatment, IkappaBalpha levels became higher than in cells treated only with cytokines. In the presence of SNP, cytokine-elicited IkappaBalpha mRNA induction was initially delayed, but was amplified at later times. These changes in IkappaBalpha expression could contribute to the dual effects of NO donors on NF-kappaB activation and COX-2 expression in HMC.
authors.affiliation: Departamento de Estructura y Función de Proteínas, Centro de Investigaciones Biológicas and Instituto Reina Sofía de Investigaciones Nefrológicas, C.S.I.C., Velázquez, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Díaz-Cazorla
authors.forename: D
authors.initials: D
authors.lastname: Pérez-Sala
authors.forename: S
authors.initials: S
authors.lastname: Lamas
mesh_terms: D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D006801:Humans; D020672:I-kappa B Proteins; D007375:Interleukin-1 / Q000494:pharmacology; D007527:Isoenzymes / Q000187:drug effects / Q000378:metabolism*; D008565:Membrane Proteins; D016328:NF-kappa B / Q000235:genetics / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009599:Nitroprusside / Q000494:pharmacology*; D009841:Oligonucleotides / Q000235:genetics / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects / Q000378:metabolism*; D026423:S-Nitroso-N-Acetylpenicillamine; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D020672:I-kappa B Proteins; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D020030:Nitric Oxide Donors; D009841:Oligonucleotides; D014409:Tumor Necrosis Factor-alpha; D009599:Nitroprusside; D026423:S-Nitroso-N-Acetylpenicillamine; D019001:Nitric Oxide Synthase; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D010396:Penicillamine; D019331:NG-Nitroarginine Methyl Ester