Expression of microsomal prostaglandin E synthase 1 in rheumatoid arthritis synovium

Arthritis Rheum. 2004 Jun;50(6):1774-80. doi: 10.1002/art.20286.


Objective: Microsomal prostaglandin E synthase 1 (mPGES-1) catalyzes the formation of PGE(2) from cyclooxygenase-derived PGH(2). Microsomal PGES-1 is induced by proinflammatory cytokines and is strongly linked to conditions that result in high PGE(2) biosynthesis. PGE(2) contributes to the pathogenesis of rheumatoid arthritis (RA), acting as a mediator of inflammation and promoting bone destruction. Induction of mPGES-1 in rheumatoid synoviocytes by proinflammatory cytokines has been demonstrated in vitro, indicating an important role in RA pathogenesis. Recent studies using mPGES-1-deficient mice demonstrated the importance of this gene in chronic inflammation. The aim of this study was to investigate the expression and localization of mPGES-1 in synovial biopsy specimens obtained from patients with RA.

Methods: Synovial tissue samples from 24 patients with RA were obtained, and immunohistologic analysis was performed using polyclonal antibodies against mPGES-1. Double immunofluorescence staining was performed with antibodies to CD3, CD19, CD20, CD68, CD163, and prolyl 4-hydroxylase.

Results: Intracellular mPGES-1 staining was observed in synovial membranes from all of the RA patients studied. Specifically, strong expression of mPGES-1 was detected in synovial lining cells. In sublining mononuclear and fibroblast-like cells, the extent of mPGES-1 staining was less than that in the synovial lining cells. In some patients, positive staining was observed in endothelial cells. With the double immunofluorescence technique, mPGES-1 production was detected in synovial macrophages and fibroblasts, while mPGES-1 expression was not observed in lymphocytes.

Conclusion: The demonstration of mPGES-1 expression in synovial tissues from patients with RA suggests a role for mPGES-1 in the RA disease process. Microsomal PGES-1 might be a potential new target for treatment strategies to control PGE(2) synthesis in patients with RA, without the systemic side effects associated with cyclooxygenase inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibody Specificity
  • Arthritis, Rheumatoid / metabolism*
  • Arthritis, Rheumatoid / pathology
  • Dinoprostone / metabolism
  • Fluorescent Antibody Technique
  • Humans
  • Intramolecular Oxidoreductases / immunology
  • Intramolecular Oxidoreductases / metabolism*
  • Microsomes / enzymology
  • Prostaglandin-E Synthases
  • Synovial Membrane / enzymology*
  • Synovial Membrane / pathology


  • Intramolecular Oxidoreductases
  • PTGES protein, human
  • Prostaglandin-E Synthases
  • Ptges protein, mouse
  • Dinoprostone