RT Journal Article
SR Electronic
T1 Role of Inducible Nitric-Oxide Synthase in Regulation of Whole-Cell Current in Lung Epithelial Cells
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 500
OP 505
VO 295
IS 2
A1 Beata Kamosinska
A1 Anna Radomski
A1 Shu Fu Paul Man
A1 Marek W. Radomski
A1 Marek Duszyk
YR 2000
UL http://jpet.aspetjournals.org/content/295/2/500.abstract
AB 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-1β, and interferon-γ for 12 h. Cytokines significantly increased the expression and activity of iNOS, and reduced generation of cGMP in response to stimulation with NO donorS-nitroso-glutathione (GSNO). Patch-clamp studies showed that 100 μM 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 μM 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−. The American Society for Pharmacology and Experimental Therapeutics