title: Lipid A-activated inducible nitric oxide synthase expression via nuclear factor-κB in mouse choroid plexus cells.
abstract: Choroid plexus (CP) which is responsible for the inflammatory mediators including nitric oxide (NO) are thought to play a crucial role in the process of bacterial meningitis. The present study investigated the mechanisms regulating inducible nitric oxide synthase (iNOS) expression in the choroid plexus epithelium (CPe) in mice. Initially, the expression of iNOS in mouse CPe was strengthened by intracerebroventriclar (i.c.v.) administration of lipid A, which is part of a Gram-negative bacterial endotoxin located at one end of the lipopolysaccharide (LPS) molecule. Next, the expression of iNOS in the CP epithelial cell line ECPC-4 cells was increased from 24 to 48h after lipid A treatment, although mRNA and proteins of toll-like receptor (TLR)-2 and -4 expressed in ECPC-4 cells were not changed by lipid A. The expression of total nuclear factor κB (NFκB), an inflammatory transcriptional factor, in ECPC-4 cells was not changed for 72 h after lipid A treatment, while cytoplasmic NFκB was decreased and nuclear NFκB was increased from 1 to 2 h. In addition, the phosphorylation of inhibitor κB (IκB) was peaked at 10 min, and the level of IκB was attenuated from 10 to 45 min after lipid A treatment. Moreover, the RNA interference (RNAi) of NFκB suppressed the expression of iNOS induced by lipid A. We demonstrated that lipid A-induced iNOS expression in ECPC-4 cells was mainly regulated by the activation of NFκB-IκB intracellular signaling pathway. Thus, we propose that the CPe plays a pivotal role in innate immunity responses of the brain, that is, the signal pathway TLRs on the CPe following inflammatory stimulation such as meningitis is activated, leading to iNOS expression through NFκB.
authors.affiliation: Laboratory of Molecular Cell Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe 650-8586, Japan. Electronic address: takano@pharm.kobegakuin.ac.jp.
authors.forename: Masaoki
authors.initials: M
authors.lastname: Takano
authors.affiliation: Laboratory of Molecular Cell Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe 650-8586, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Ohkusa
authors.affiliation: Laboratory of Molecular Cell Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe 650-8586, Japan.
authors.forename: Mieko
authors.initials: M
authors.lastname: Otani
authors.affiliation: Laboratory of Toxicology, Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikigorikita, Tondabayashi, Osaka 584-8540, Japan.
authors.forename: Kyong-Son
authors.initials: KS
authors.lastname: Min
authors.affiliation: Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kamiohno, Himeji 670-8524 Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kadoyama
authors.affiliation: Laboratory of Molecular Cell Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe 650-8586, Japan.
authors.forename: Katori
authors.initials: K
authors.lastname: Minami
authors.affiliation: Laboratory of Molecular Cell Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe 650-8586, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Sano
authors.affiliation: Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kamiohno, Himeji 670-8524 Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Matsuyama
mesh_terms: D000818:Animals; D002460:Cell Line; D002831:Choroid Plexus / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing; D008050:Lipid A / Q000276:immunology* / Q000494:pharmacology; D051379:Mice; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D034622:RNA Interference; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D008050:Lipid A; D016328:NF-kappa B; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D052247:Nitric Oxide Synthase Type II
keywords: Choroid plexus; IκB; Lipid A; NFκB; RNAi; iNOS