Role of reactive oxygen species in LPS-induced production of prostaglandin E2 in microglia

J Neurochem. 2004 Feb;88(4):939-47. doi: 10.1046/j.1471-4159.2003.02242.x.

Abstract

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.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Animals, Newborn
  • Blotting, Western / methods
  • Brain / cytology
  • Catalase / pharmacology
  • Catecholamines / pharmacology
  • Cell Count
  • Cells, Cultured
  • Cyclooxygenase 2
  • Dinoprostone / metabolism*
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism
  • Female
  • Fluoresceins / pharmacology
  • Imidazolines*
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Lipopolysaccharides / pharmacology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microglia / drug effects*
  • Microglia / metabolism
  • NADPH Oxidases / genetics
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase / metabolism
  • Nitric Oxide Synthase Type II
  • Organometallic Compounds / pharmacology
  • Pregnancy
  • Prostaglandin-Endoperoxide Synthases / genetics
  • Prostaglandin-Endoperoxide Synthases / metabolism
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Inbred F344
  • Reactive Oxygen Species / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Salicylates / pharmacology
  • Superoxide Dismutase / pharmacology
  • Tetrazolium Salts / pharmacology
  • Thiazoles / pharmacology

Substances

  • Catecholamines
  • EUK-134
  • EUK-189
  • Fluoresceins
  • Imidazolines
  • Isoenzymes
  • Lipopolysaccharides
  • Organometallic Compounds
  • RNA, Messenger
  • Reactive Oxygen Species
  • Salicylates
  • Tetrazolium Salts
  • Thiazoles
  • diacetyldichlorofluorescein
  • Nitric Oxide
  • (3,4-dihydroxyphenylamino)-2-imidazoline
  • Catalase
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse
  • Nos2 protein, rat
  • Cyclooxygenase 2
  • Prostaglandin-Endoperoxide Synthases
  • Superoxide Dismutase
  • NADPH Oxidases
  • thiazolyl blue
  • Dinoprostone