Interleukin-1 beta stimulates cytosolic phospholipase A2 in rheumatoid synovial fibroblasts

Biochem Biophys Res Commun. 1992 Apr 30;184(2):712-8. doi: 10.1016/0006-291x(92)90648-5.


Phospholipase A2 (PLA2) activities in rheumatoid synovial fibroblasts (RSF) stimulated with interleukin-1 beta (IL-1 beta) were investigated. RSF incubated in the presence of IL-1 beta (120 pg/ml) for 18 h secreted 35 fold more PGE2 than did those incubated without IL-1 beta. IL-1 beta treatment did not increase the level of secretory PLA2 (sPLA2) activity or sPLA2 protein in the conditioned medium or subcellular fractions of lysed RSF. In contrast, the cell-associated PLA2 activity increased 3 to 4 fold in IL-1 beta stimulated RSF when compared with the control. The IL-1 beta stimulated, cell-associated PLA2 required submicromolar concentrations of calcium for activity, a characteristic consistent with the calcium sensitivity of cytosolic PLA2 (cPLA2) activity reported in other cell types, such as U937 cells. These findings demonstrate that an elevation in a cytosolic PLA2, rather than a sPLA2, is associated with increased PGE2 production in IL-1 beta stimulated RSF.

MeSH terms

  • Arthritis, Rheumatoid / enzymology*
  • Cell Fractionation
  • Cells, Cultured
  • Cytosol / enzymology
  • Dinoprostone / metabolism
  • Fibroblasts / enzymology
  • Humans
  • Interleukin-1 / pharmacology*
  • Kinetics
  • Phospholipases A / metabolism*
  • Phospholipases A2
  • Recombinant Proteins / pharmacology
  • Subcellular Fractions / enzymology
  • Synovial Membrane / enzymology*


  • Interleukin-1
  • Recombinant Proteins
  • Phospholipases A
  • Phospholipases A2
  • Dinoprostone