title: The inhibitory action of sodium arsenite on lipopolysaccharide-induced nitric oxide production in RAW 267.4 macrophage cells: a role of Raf-1 in lipopolysaccharide signaling.
abstract: The effect of sodium arsenite (SA) on LPS-induced NO production in RAW 267.4 murine macrophage cells was studied. SA pretreatment of LPS-stimulated RAW cells resulted in a striking reduction in NO production. No significant difference in LPS binding was observed between RAW cells pretreated with SA and control untreated RAW cells, suggesting that SA might impair the intracellular signal pathway for NO production. SA inhibited LPS-induced NF-kappaB activation by preventing loss of IkappaB-alpha and -beta. Furthermore, SA blocked phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2), but not phosphorylation of p38 and c-Jun N-terminal kinase. SA treatment resulted in the disappearance of Raf-1, suggesting that it might cause the inhibition of the Erk1/2 mitogen-activated protein (MAP) kinase pathway. The SA-mediated loss of Raf-1 also abolished LPS-induced NF-kappaB activation as well as the Erk1/2 pathway. The dominant negative mutant of MAP kinase kinase 1 inhibited both NO production and NF-kappaB activation in LPS-stimulated RAW cells. Taken together, these results indicate that the inhibitory action of SA on NO production in LPS-stimulated macrophages might be due to abrogation of inducible NO synthase induction, and it might be closely related to inactivation of the NF-kappaB and Erk1/2 MAP kinase pathways through loss of Raf-1.
authors.affiliation: Department of Microbiology and Immunology and Division of Bacterial Toxin, Research Center for Infectious Disease, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Chakravortty
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
authors.forename: T
authors.initials: T
authors.lastname: Sugiyama
authors.forename: N
authors.initials: N
authors.lastname: Koide
authors.forename: M M
authors.initials: MM
authors.lastname: Mu
authors.forename: T
authors.initials: T
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Yokochi
mesh_terms: D000818:Animals; D018053:Arsenites / Q000494:pharmacology*; D016227:Benzoquinones; D001665:Binding Sites / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D004795:Enzyme Stability / Q000187:drug effects; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D047029:Lactams, Macrocyclic; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D048728:MAP Kinase Kinase Kinase 1; D046911:Macromolecular Substances; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010587:Phagocytosis / Q000276:immunology; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism / Q000502:physiology*; D011809:Quinones / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D017670:Sodium Compounds / Q000494:pharmacology*; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D018053:Arsenites; D016227:Benzoquinones; D018841:HSP90 Heat-Shock Proteins; D007166:Immunosuppressive Agents; D047029:Lactams, Macrocyclic; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D046911:Macromolecular Substances; D016328:NF-kappa B; D016376:Oligonucleotides, Antisense; D011809:Quinones; D017670:Sodium Compounds; D009569:Nitric Oxide; C017947:sodium arsenite; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D048031:JNK Mitogen-Activated Protein Kinases; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482578:Map3k1 protein, mouse; D016650:Fluorescein-5-isothiocyanate; C001277:geldanamycin