title: The role of cyclo-oxygenase 1 and 2 activity in prostaglandin E(2) secretion by cultured human adult microglia: implications for Alzheimer's disease.
abstract: Microglial cyclo-oxygenase (COX) expression is considered to be important in the pathogenesis of Alzheimer's disease (AD) and, therefore, constitutes a key target for therapeutic intervention. We investigated the influence of AD plaque associated factors on COX-1 and COX-2 expression and activity in adult human microglial cells in vitro. COX-2 immunoreactivity and mRNA were induced by lipopolysaccharide (LPS), not by AD plaque associated cytokines interleukin (IL)-1alpha, IL-1beta, IL-6, tumor necrosis factor (TNF)-alpha, or amyloid (A)beta(1-42). To assess functional COX activity, the release of PGE(2) into the culture medium was determined. LPS and also arachidonic acid (AA) dose-dependently stimulated PGE(2) release. The effects of AA are independent from induction of COX mRNA expression, or of de novo protein synthesis. No effects of either plaque-associated cytokines or Abeta(1-42) on PGE(2) secretion were seen, even when cells were co-stimulated with AA, to provide enough substrate. COX isotype selective inhibitors were used to discern relative contributions of COX-1 and COX-2 activities to microglial PGE(2) secretion. COX-2 and in part COX-1-selective inhibitors inhibited LPS-induced PGE(2) secretion, whereas the AA-induced PGE(2) secretion was reduced by COX-1-selective inhibitors only. Apparently, adult human microglia in vitro (1) constitutively express COX-1, and (2) do not express COX-2 upon exposure to either Abeta or plaque associated cytokines. In the light of microglial COX activity as a potential therapeutical target in AD, the data presented in this study suggest that classical NSAIDs, rather than selective COX-2 inhibitors, are more potent in reducing microglial prostaglandin secretion.
authors.affiliation: Department of Pathology, Graduate School Neurosciences Amsterdam, Research Institute Neurosciences, Vrije Universiteit Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands. jjm.hoozemans@vumc.nl
authors.forename: Jeroen J M
authors.initials: JJ
authors.lastname: Hoozemans
authors.forename: Robert
authors.initials: R
authors.lastname: Veerhuis
authors.forename: Ingrid
authors.initials: I
authors.lastname: Janssen
authors.forename: Evert-Jan
authors.initials: EJ
authors.lastname: van Elk
authors.forename: Annemieke J M
authors.initials: AJ
authors.lastname: Rozemuller
authors.forename: Piet
authors.initials: P
authors.lastname: Eikelenboom
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000201:enzymology*; D016229:Amyloid beta-Peptides / Q000378:metabolism / Q000494:pharmacology; D016718:Arachidonic Acid / Q000494:pharmacology; D001921:Brain / Q000166:cytology; D002478:Cells, Cultured; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D016207:Cytokines / Q000096:biosynthesis; D015232:Dinoprostone / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008565:Membrane Proteins; D017628:Microglia / Q000201:enzymology* / Q000378:metabolism*; D008875:Middle Aged; D010446:Peptide Fragments / Q000494:pharmacology; D058225:Plaque, Amyloid / Q000378:metabolism / Q000473:pathology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D016229:Amyloid beta-Peptides; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D016207:Cytokines; D007527:Isoenzymes; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016718:Arachidonic Acid; D012313:RNA; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone