title: Nuclear factor-kappa B and mitogen-activated protein kinases mediate nitric oxide-enhanced transcriptional expression of interferon-beta.
abstract: Mitogen-activated protein (MAP) kinase and nuclear factor-kappaB (NF-kappaB) activation are critical for initiating the transcriptional expression of cytokines, cell adhesion molecules, and other factors in the macrophage immune response. Nitric oxide (NO), an endogenous free radical, is a product of macrophages that mediates inflammatory and cytotoxic processes in the immune system. Here we report the effects of NO on MAP kinase signaling and NF-kappaB activation in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and correlate these effects to the induction target genes, including interferon-beta (IFN-beta) and IkappaB-alpha. LPS alone induced a rapid phosphorylation of the stress-activated MAP kinases: c-Jun N-terminal kinase (JNK) and p38. Simultaneous treatment with LPS and the NO donor, diethylamine NONOate (DEA/NO), enhanced and prolonged JNK and p38 phosphorylation. Similarly, DEA/NO prolonged the LPS-induced degradation of the NF-kappaB inhibitory subunit, IkappaB-alpha, despite an increase in IkappaB-alpha mRNA levels. Whereas DEA/NO alone was sufficient to induce JNK and p38 phosphorylation, it was not sufficient to cause IkappaB-alpha degradation. The enhancement of IkappaB-alpha degradation by DEA/NO correlated with an increase in the nuclear levels of the p50 and p65 subunits and DNA-binding activity determined by electrophoretic mobility shift assay. DEA/NO and an additional NO donor, MAHMA/NO, are further demonstrated to enhance the transcriptional expression of the IFN-beta gene. The results suggest a role for NO in enhancing and propagating inflammatory conditions and the immune response.
authors.affiliation: Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California 90095, USA.
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Jacobs
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Ignarro
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation / Q000187:drug effects*; D020672:I-kappa B Proteins / Q000235:genetics; D016899:Interferon-beta / Q000235:genetics*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010766:Phosphorylation; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D017931:DNA Primers; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D020030:Nitric Oxide Donors; D000072000:NF-KappaB Inhibitor alpha; D009569:Nitric Oxide; D016899:Interferon-beta; D020928:Mitogen-Activated Protein Kinases