Role of reactive oxygen species in LPS-induced production of prostaglandin E2 in microglia.
We determined the roles of reactive oxygen species (ROS) in the expression of cyclooxygenase-2 (COX-2) and the production of prostaglandin E2 (PGE2) in lipopolysaccharide (LPS)-activated microglia. LPS treatment increased intracellular ROS in rat microglia dose-dependently. Pre-treatment with superoxide dismutase (SOD)/catalase, or SOD/catalase mimetics that can scavenge intracellular ROS, significantly attenuated LPS-induced release in PGE2. Diphenylene iodonium (DPI), a non-specific NADPH oxidase inhibitor, decreased LPS-induced PGE2 production. In addition, microglia from NADPH oxidase-deficient mice produced less PGE2 than those from wild-type mice following LPS treatment. Furthermore, LPS-stimulated expression of COX-2 (determined by RT-PCR analysis of COX-2 mRNA and western blot for its protein) was significantly reduced by pre-treatment with SOD/catalase or SOD/catalase mimetics. SOD/catalase mimetics were more potent than SOD/catalase in reducing COX-2 expression and PGE2 production. As a comparison, scavenging ROS had no effect on LPS-induced nitric oxide production in microglia. These results suggest that ROS play a regulatory role in the expression of COX-2 and the subsequent production of PGE2 during the activation process of microglia. Thus, inhibiting NADPH oxidase activity and subsequent ROS generation in microglia can reduce COX-2 expression and PGE2 production. These findings suggest a potential therapeutic intervention strategy for the treatment of inflammation-mediated neurodegenerative diseases.
Wang
Tongguang
T
Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, North Carolina 27709, USA.
Qin
Liya
L
Liu
Bin
B
Liu
Yuxin
Y
Wilson
Belinda
B
Eling
Thomas E
TE
Langenbach
Robert
R
Taniura
Seijiro
S
Hong
Jau-Shyong
JS
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western / Q000379:methods; D001921:Brain / Q000166:cytology; D002374:Catalase / Q000494:pharmacology; D002395:Catecholamines / Q000494:pharmacology; D002452:Cell Count; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005452:Fluoresceins / Q000494:pharmacology; D048288:Imidazolines; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D019255:NADPH Oxidases / Q000235:genetics; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009942:Organometallic Compounds / Q000494:pharmacology; D011247:Pregnancy; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012459:Salicylates / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000494:pharmacology; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology
D002395:Catecholamines; C433928:EUK-134; C436526:EUK-189; D005452:Fluoresceins; D048288:Imidazolines; D007527:Isoenzymes; D008070:Lipopolysaccharides; D009942:Organometallic Compounds; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D012459:Salicylates; D013778:Tetrazolium Salts; D013844:Thiazoles; C029569:diacetyldichlorofluorescein; D009569:Nitric Oxide; C011775:(3,4-dihydroxyphenylamino)-2-imidazoline; D002374:Catalase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; C022616:thiazolyl blue; D015232:Dinoprostone