title: Double-stranded RNA-induced inducible nitric-oxide synthase expression and interleukin-1 release by murine macrophages requires NF-kappaB activation.
abstract: The effects of double-stranded RNA (synthetic polyinosinic-polycytidylic acid; poly(I-C)) on macrophage expression of inducible nitric-oxide synthase (iNOS), production of nitric oxide, and release of interleukin-1 (IL-1) were investigated. Individually, poly(I-C), interferon-gamma (IFN-gamma), and lipopolysaccharide (LPS) stimulate nitrite production and iNOS expression by RAW 264.7 cells. In combination, the effects of poly(I-C) + IFN-gamma are additive, while poly(I-C) does not further potentiate LPS-induced nitrite production. These results suggest that poly(I-C) and LPS may stimulate iNOS expression by similar signaling pathways, which may be independent of pathways activated by IFN-gamma. LPS-induced iNOS expression is associated with the activation of NF-kappaB. We show that inhibition of NF-kappaB by pyrrolidinedithiocarbamate prevents poly(I-C) + IFN-gamma-, poly(I-C) + LPS-, and LPS-induced iNOS expression, nitrite production and IkappaB degradation by RAW 264.7 cells. The effects of poly(I-C) on iNOS expression appear to be cell-type specific. Poly(I-C), alone or in combination with IFN-gamma, does not stimulate, nor does poly(I-C) potentiate, IL-1-induced nitrite production by rat insulinoma RINm5F cells. In addition, we show that the combination of poly(I-C) + IFN-gamma stimulates iNOS expression, nitrite production, IkappaB degradation, and the release of IL-1 by primary mouse macrophages, and these effects are prevented by pyrrolidinedithiocarbamate. These findings indicate that double-stranded RNA, in the presence of IFN-gamma, is a potent activator of macrophages, stimulating iNOS expression, nitrite production, and IL-1 release by a mechanism which requires the activation of NF-kappaB.
authors.affiliation: Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri 63104, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Heitmeier
authors.forename: A L
authors.initials: AL
authors.lastname: Scarim
authors.forename: J A
authors.initials: JA
authors.lastname: Corbett
mesh_terms: D000818:Animals; D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000201:enzymology*; D051379:Mice; D016328:NF-kappa B / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D011070:Poly I-C / Q000494:pharmacology; D011392:Proline / Q000031:analogs & derivatives / Q000494:pharmacology; D012330:RNA, Double-Stranded / Q000494:pharmacology*; D051381:Rats; D015398:Signal Transduction / Q000502:physiology; D013859:Thiocarbamates / Q000494:pharmacology
chemical_list: D007375:Interleukin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012330:RNA, Double-Stranded; D013859:Thiocarbamates; C066229:prolinedithiocarbamate; D009569:Nitric Oxide; D007371:Interferon-gamma; D011392:Proline; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; D011070:Poly I-C