title: Prostaglandin E2 receptors EP2 and EP4 are up-regulated in peritoneal macrophages and joints of pristane-treated mice and modulate TNF-alpha and IL-6 production.
abstract: Prostaglandin E(2) (PGE(2)) can have pro- or anti-inflammatory effects, depending on engagement of different PGE(2) receptor (EP) subtypes. The role of EPs in regulating autoimmune inflammation was studied in the murine arthritis/lupus model induced by pristane. Peritoneal macrophages were isolated (biomagnetic beads) from BALB/c, DBA/1, or C57BL/6 mice treated with pristane (intraperitoneally, 3 months earlier) or thioglycolate (3 days earlier) or with untreated controls. EPs, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) mRNA expression was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Cells were cultured unstimulated or stimulated with lipopolysaccharide (LPS) or LPS + interferon-gamma in combination with EP subtype-specific agonists. Tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-6 production was tested by enzyme-linked immunosorbent assay (culture supernatant) and flow cytometry. TNF-alpha mRNA levels also were examined. High levels of EPs (EP4/2>EP1>EP3), iNOS, and COX-2 mRNA were expressed in peritoneal macrophages from pristane-treated but not untreated or thioglycolate-treated mice (RT-PCR). TNF-alpha production was inhibited 50-70% at 2-24 h by EP4/2 agonists, whereas IL-6 was enhanced up to approximately 220%. TNF-alpha inhibition is mediated partly via the protein kinase A pathway and partly via IL-6. Intracellular TNF-alpha staining was inhibited 20% by EP4/2 agonists. TNF-alpha mRNA levels were inhibited 50-70% at 2-24 h, indicating that TNF-alpha inhibition was partly at the level of transcription. EP1/3 agonists had little effect. Synovial cells from mice with pristane-induced arthritis (DBA/1) also expressed EP2/4, and the EP2/4 agonist inhibited TNF-alpha production. PGE(2) can modulate inflammatory reactions via the EP2/4 receptor through its regulation of TNF-alpha and IL-6. Modification of EP signaling may be a new therapeutic strategy in inflammatory/autoimmune diseases.
authors.affiliation: University of Florida, P.O. Box 100221, Gainesville, FL 32610-0221, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Akaogi
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Yamada
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kuroda
authors.forename: Dina C
authors.initials: DC
authors.lastname: Nacionales
authors.forename: Westley H
authors.initials: WH
authors.lastname: Reeves
authors.forename: Minoru
authors.initials: M
authors.lastname: Satoh
mesh_terms: D000818:Animals; D001168:Arthritis / Q000139:chemically induced; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D007166:Immunosuppressive Agents / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis*; D007527:Isoenzymes / Q000096:biosynthesis / Q000187:drug effects; D007596:Joints / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000187:drug effects; D052247:Nitric Oxide Synthase Type II; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis / Q000187:drug effects; D018078:Receptors, Prostaglandin E / Q000187:drug effects / Q000378:metabolism*; D058309:Receptors, Prostaglandin E, EP4 Subtype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013583:Synovial Membrane / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D013729:Terpenes / Q000494:pharmacology; D013864:Thioglycolates / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000187:drug effects*; D015854:Up-Regulation
chemical_list: D007166:Immunosuppressive Agents; D015850:Interleukin-6; D007527:Isoenzymes; C545651:Ptger4 protein, mouse; D018078:Receptors, Prostaglandin E; D058309:Receptors, Prostaglandin E, EP4 Subtype; D013729:Terpenes; D013864:Thioglycolates; D014409:Tumor Necrosis Factor-alpha; C009042:pristane; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases