title: Activation of p38 MAPK induced peroxynitrite generation in LPS plus IFN-gamma-stimulated rat primary astrocytes via activation of iNOS and NADPH oxidase.
abstract: We have shown that immunostimulated astrocytes produce excess nitric oxide (NO) and eventually peroxynitrite (ONOO(-)) that was closely associated with the glucose deprivation-potentiated death of astrocytes. The present study shows that activated p38 MAPK regulates ONOO(-) generation from lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma)-stimulated astrocytes. LPS+IFN-gamma-induced p38 MAPK activation and ONOO(-) generation were attenuated by SB203580 or SKF-86002, specific inhibitors of p38 MAPK. ONOO(-) generation was blocked by NADPH oxidase inhibitor, diphenyleneiodonium chloride, and nitric oxide synthase (NOS) inhibitor, N omega-nitro-L-arginine methyl ester, suggesting both enzymes are involved in ONOO(-) generation. Inhibition of p38 MAPK suppressed LPS+IFN-gamma-induced NO production through down-regulating inducible form of NOS expression. It also suppressed LPS+IFN-gamma-induced NADPH oxidase activation and eventually, the inducible form of superoxide production. Transfection with dominant negative vector of p38 alpha reduced LPS+IFN-gamma-induced ONOO(-) generation through blocking both iNOS-derived NO production and NADPH oxidase-derived O2(-) production. Our results suggest that activated p38 MAPK may serve as a potential signaling molecule in ONOO(-) generation through dual regulatory mechanisms, involving iNOS induction and NADPH oxidase activation.
authors.affiliation: Department of Pharmacology, College of Pharmacy, Seoul National University, San 56-1, Shinlim-Dong, Kwanak-Gu, Seoul 151-742, Republic of Korea.
authors.forename: Byoung Kwon
authors.initials: BK
authors.lastname: Yoo
authors.forename: Ji Woong
authors.initials: JW
authors.lastname: Choi
authors.forename: Chan Young
authors.initials: CY
authors.lastname: Shin
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Jeon
authors.forename: Seo Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Cheong
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Han
authors.forename: Jae Ryun
authors.initials: JR
authors.lastname: Ryu
authors.forename: Mi Ryoung
authors.initials: MR
authors.lastname: Song
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Ko
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D004660:Encephalitis / Q000201:enzymology* / Q000276:immunology / Q000503:physiopathology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007371:Interferon-gamma / Q000276:immunology / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D019255:NADPH Oxidases / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D030421:Peroxynitrous Acid / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D007371:Interferon-gamma; D052247:Nitric Oxide Synthase Type II; D019255:NADPH Oxidases; D048051:p38 Mitogen-Activated Protein Kinases