Nitric oxide suppresses IL-8 transcription by inhibiting c-Jun N-terminal kinase-induced AP-1 activation.
The role of activator protein-1 (AP-1) in tumor necrosis factor-alpha (TNF-alpha)-induced interleukin-8 (IL-8) gene expression was evaluated. We showed that TNF-alpha activates AP-1 in the transformed endothelial cell line ECV304 by transient transfections of IL-8 promoter construct pGL-3BF(2). Mutation of either the AP-1 site or the NF-IL-6 site on the IL-8 promoter suppressed the TNF-alpha-induced activation, suggesting cooperation between these transcription factors and transcription factor NF-kappaB. Overexpression of dominant negative mutants of c-Jun suppressed AP-1-driven transcription of the IL-8 promoter following stimulation by TNF-alpha, suggesting that cooperative interaction between AP-1 and NF-kappaB is essential for IL-8 transcription in the presence of TNF-alpha. We also showed that nitric oxide (NO), in the form of an exogenous NO donor, suppressed the level of activation of the AP-1 subunit, c-Jun, by down-regulation of c-Jun NH2 terminal kinase. This down-regulation could be the putative mechanism of action for NO-mediated inhibition of IL-8 secretion in activated endothelium. These observations suggest for the first time that NO has broad suppressive activities on various proinflammatory effectors in activated endothelium.
Natarajan
R
R
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
Gupta
S
S
Fisher
B J
BJ
Ghosh
S
S
Fowler
A A
AA
D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D015536:Down-Regulation; D004727:Endothelium / Q000187:drug effects / Q000378:metabolism*; D005978:Glutathione / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics*; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D009154:Mutation; D009569:Nitric Oxide / Q000502:physiology*; D009603:Nitroso Compounds / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D026422:S-Nitrosoglutathione; D018808:Transcription Factor AP-1 / Q000378:metabolism* / Q000502:physiology; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D022782:CCAAT-Enhancer-Binding Protein-beta; D016209:Interleukin-8; D009603:Nitroso Compounds; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D004247:DNA; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D005978:Glutathione