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

J Leukoc Biol. 2004 Jul;76(1):227-36. doi: 10.1189/jlb.1203627. Epub 2004 Apr 1.


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.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Arthritis / chemically induced
  • Cells, Cultured
  • Cyclooxygenase 2
  • Disease Models, Animal
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Flow Cytometry
  • Immunosuppressive Agents / pharmacology
  • Interleukin-6 / biosynthesis*
  • Isoenzymes / biosynthesis
  • Isoenzymes / drug effects
  • Joints / immunology*
  • Macrophages, Peritoneal / immunology*
  • Mice
  • Mice, Inbred Strains
  • Nitric Oxide Synthase / biosynthesis
  • Nitric Oxide Synthase / drug effects
  • Nitric Oxide Synthase Type II
  • Prostaglandin-Endoperoxide Synthases / biosynthesis
  • Prostaglandin-Endoperoxide Synthases / drug effects
  • Receptors, Prostaglandin E / drug effects
  • Receptors, Prostaglandin E / metabolism*
  • Receptors, Prostaglandin E, EP4 Subtype
  • Reverse Transcriptase Polymerase Chain Reaction
  • Synovial Membrane / cytology
  • Synovial Membrane / drug effects
  • Synovial Membrane / immunology
  • Terpenes / pharmacology
  • Thioglycolates / pharmacology
  • Tumor Necrosis Factor-alpha / biosynthesis
  • Tumor Necrosis Factor-alpha / drug effects*
  • Up-Regulation


  • Immunosuppressive Agents
  • Interleukin-6
  • Isoenzymes
  • Ptger4 protein, mouse
  • Receptors, Prostaglandin E
  • Receptors, Prostaglandin E, EP4 Subtype
  • Terpenes
  • Thioglycolates
  • Tumor Necrosis Factor-alpha
  • pristane
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse
  • Cyclooxygenase 2
  • Prostaglandin-Endoperoxide Synthases