title: Co-induction of argininosuccinate synthetase, cationic amino acid transporter-2, and nitric oxide synthase in activated murine microglial cells.
abstract: Nitric oxide (NO) produced by activated microglia has been implicated in many pathophysiological events in the brain including neurodegenerative diseases. Cellular NO production depends absolutely on the availability of arginine, a substrate of NO synthase (NOS). Murine microglial MG5 cells were treated with bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma), and expression of inducible NO synthase (iNOS) and arginine-supplying enzymes was investigated by RNA blot analysis. iNOS mRNA was strongly induced after treatment and reached a maximum at 6-12 h. mRNA for argininosuccinate synthetase (AS), a citrulline-arginine recycling enzyme, increased at 6 h and reached a maximum at 12 h. Immunoblot analysis showed that iNOS and AS proteins were also induced. In addition, mRNA encoding the cationic amino acid transporter-2 (CAT-2) was strongly induced shortly after treatment. Induction of mRNAs for iNOS, AS, and CAT-2 by LPS/IFN-gamma was also observed following stimulation of rat primary microglial cells. These results strongly suggest that both arginine transport by CAT-2 and citrulline-arginine recycling are important for high-output production of NO in activated microglial cells.
authors.affiliation: Department of Biofunctional Chemistry, Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Ohe-Honmachi, 862-0973, Kumamoto, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kawahara
authors.forename: T
authors.initials: T
authors.lastname: Gotoh
authors.forename: S
authors.initials: S
authors.lastname: Oyadomari
authors.forename: M
authors.initials: M
authors.lastname: Kajizono
authors.forename: A
authors.initials: A
authors.lastname: Kuniyasu
authors.forename: K
authors.initials: K
authors.lastname: Ohsawa
authors.forename: Y
authors.initials: Y
authors.lastname: Imai
authors.forename: S
authors.initials: S
authors.lastname: Kohsaka
authors.forename: H
authors.initials: H
authors.lastname: Nakayama
authors.forename: M
authors.initials: M
authors.lastname: Mori
mesh_terms: D026923:Amino Acid Transport Systems, Basic; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001124:Argininosuccinate Synthase / Q000235:genetics* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D002956:Citrulline / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D007371:Interferon-gamma / Q000494:pharmacology; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D017628:Microglia / Q000166:cytology / Q000201:enzymology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar
chemical_list: D026923:Amino Acid Transport Systems, Basic; D000970:Antineoplastic Agents; D002352:Carrier Proteins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D012333:RNA, Messenger; D002956:Citrulline; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; D001124:Argininosuccinate Synthase