Phospholipase A2 (PLA2) activity in bovine pulmonary artery endothelial cells

We have investigated the role of recombinant human interleukin-1β (rIL-1β) and recombinant human tumor necrosis factorα (rTNF-α) on PLA2 activity, protein synthesis and eicosanoid production in bovine pulmonary artery endothelial cells. Cellular PLA2 activity increased 4-fold and production of PGE2 increased 3-fold at 1–2 hrs in the presence of 10 units/ml rIL-1β. PLA2 activity increased 3-fold at 30 min and PGE2 production increased 2-fold with 5×10−9M rTNF-α. The data show that endothelial cells respond more rapidly to rIL-1β (2–6 hr) and rTNF-α (30 min) than do chondrocytes and synovial cells (6–16 hrs), suggesting endothelial cells may play a primary role in initiating the inflammatory response.