Negative regulation by phosphatidylinositol 3-kinase of inducible nitric oxide synthase expression in macrophages.
Triggering of the macrophage cell line RAW 264.7 with LPS promotes a transient activation of phosphatidylinositol 3-kinase (PI3-kinase). Incubation of activated macrophages with wortmannin and LY294002, two inhibitors of PI3-kinase, increased the amount of inducible nitric oxide synthase (iNOS) and the synthesis of nitric oxide. Treatment with wortmannin promoted a prolonged activation of NF-kappaB in LPS-treated cells as well as an increase in the promoter activity of the iNOS gene as deduced from transfection experiments using a 1.7-kb fragment of the 5' flanking region of the iNOS gene. Cotransfection of cells with a catalytically active p110 subunit of PI3-kinase impaired the responsiveness of the iNOS promoter to LPS stimulation, whereas transfection with a kinase-deficient mutant of p110 maintained the up-regulation in response to wortmannin. These results indicate that PI3-kinase plays a negative role in the process of macrophage activation and suggest that this enzyme might participate in the mechanism of action of antiinflammatory cytokines.
Díaz-Guerra
M J
MJ
Instituto de Bioquímica, Facultad de Farmacia, 28040 Madrid, Spain.
Castrillo
A
A
Martín-Sanz
P
P
Boscá
L
L
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D002867:Chromones / Q000494:pharmacology; D004789:Enzyme Activation; D016753:Interleukin-10 / Q000276:immunology; D018793:Interleukin-13 / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation / Q000276:immunology*; D008264:Macrophages / Q000201:enzymology / Q000276:immunology*; D051379:Mice; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D014158:Transcription, Genetic; D015854:Up-Regulation; D000077191:Wortmannin
D000730:Androstadienes; D002867:Chromones; D016753:Interleukin-10; D018793:Interleukin-13; D008070:Lipopolysaccharides; D009025:Morpholines; D016328:NF-kappa B; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C496317:Nos2 protein, mouse