title: Role of inducible nitric-oxide synthase in regulation of whole-cell current in lung epithelial cells.
abstract: Lung inflammation is associated with enhanced expression of proinflammatory cytokines and increased production of nitric oxide (NO) by inducible NO synthase (iNOS). To investigate the possible relationship between cytokine-induced expression of iNOS and epithelial ion channel function, we measured whole-cell current in A549 cells treated with a mixture of cytokines: tumor necrosis factor, interleukin-1 beta, and interferon-gamma for 12 h. Cytokines significantly increased the expression and activity of iNOS, and reduced generation of cGMP in response to stimulation with NO donor S-nitroso-glutathione (GSNO). Patch-clamp studies showed that 100 microM GSNO increased the whole-cell current from 11.2 +/- 1.8 to 19.6 +/- 2.7 pA/pF (n = 16) in control cells, but had no effect in cytokine-treated cells (n = 9). N-(3-(Aminomethyl)benzyl)acetamidine (1400W), a selective inhibitor of iNOS, restored activation of the current by GSNO in cytokine-treated cells, indicating a crucial role for iNOS in this process. Cells treated with cytokines showed increased levels of peroxynitrite (ONOO(-)), compared with the control, or cells that were treated with the cytokines and 1400W or superoxide dismutase/catalase. Treatment of cells with 100 microM ONOO(-) had no effect on the whole-cell current, but in contrast to untreated cells, subsequent application of GSNO did not activate the current. In conclusion, cytokine-induced expression of iNOS affects activation of the whole-cell current via NO/cGMP pathway, likely by increasing the generation of ONOO(-).
authors.affiliation: Department of Physiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Kamosinska
authors.forename: A
authors.initials: A
authors.lastname: Radomski
authors.forename: S F
authors.initials: SF
authors.lastname: Man
authors.forename: M W
authors.initials: MW
authors.lastname: Radomski
authors.forename: M
authors.initials: M
authors.lastname: Duszyk
mesh_terms: D006152:Cyclic GMP / Q000378:metabolism / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology*; D004789:Enzyme Activation; D005978:Glutathione / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D007473:Ion Channels / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009566:Nitrates / Q000378:metabolism / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009603:Nitroso Compounds / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011994:Recombinant Proteins; D026422:S-Nitrosoglutathione; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D007473:Ion Channels; D009566:Nitrates; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C039642:peroxynitric acid; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D007371:Interferon-gamma; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D005978:Glutathione; D006152:Cyclic GMP