Prostaglandins prevent inducible nitric oxide synthase protein expression by inhibiting nuclear factor-kappaB activation in J774 macrophages.
We investigated the effect of PGE2 and iloprost (a prostacyclin analogue) on inducible nitric oxide synthase (iNOS) protein expression and nuclear factor-kappaB (NF-kappaB) activation in lipopolysaccharide (LPS)-stimulated J774 macrophages. Incubation of J774 cells with LPS (10 microg/ml) caused an increase of iNOS protein expression which was prevented in a concentration-dependent fashion by PGE2 (0.1, 1, 10 microM) and iloprost (0.01, 0.1, 1 microM). Electrophoretic mobility shift assay indicated that both prostanoids blocked the activation of NF-kappaB, a transcription factor necessary for NO synthase induction. PGE2 and iloprost also blocked disappearance of I kappaB-alpha from cytosolic fraction and nuclear translocation of NF-kappaB subunits p50 and p65. These results show for the first time that PGE2 and iloprost down-regulate iNOS protein expression by inhibiting NF-kappaB activation and suggest a negative feed-back mechanism that may be important for limiting excessive or prolonged NO production in pathological events.
D'Acquisto
F
F
Department of Experimental Pharmacology, University of Naples Federico II, Italy.
Sautebin
L
L
Iuvone
T
T
Di Rosa
M
M
Carnuccio
R
R
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000378:metabolism; D015232:Dinoprostone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic; D020672:I-kappa B Proteins; D016285:Iloprost / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D051996:Transcription Factor RelA
D015342:DNA Probes; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; C000606205:Nfkbia protein, mouse; D009573:Nitrites; D051996:Transcription Factor RelA; D000072000:NF-KappaB Inhibitor alpha; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D016285:Iloprost; D015232:Dinoprostone