Interleukin-1 alpha induces the accumulation of cytosolic phospholipase A2 and the release of prostaglandin E2 in human fibroblasts.

Treatment of the human lung fibroblast cell line, WI-38, with interleukin-1 alpha (IL-1 alpha) results in a large increase in the production of cytosolic phospholipase A2 (cPLA2) and prostaglandin E2 (PGE2). The IL-1-induced accumulation of cPLA2 is closely correlated with increased PGE2 release. In contrast to cPLA2, the level of cyclooxygenase remains unchanged following IL-1 alpha treatment. The glucocorticoid, dexamethasone, blocks the IL-1 alpha-mediated increases in both cPLA2 and PGE2 without affecting the cyclooxygenase level. Taken together, these data suggest that in these cells, the regulation of prostaglandin production by IL-1 and glucocorticoid can be attributed to the level of cPLA2. These results provide a new mechanism for the effect of IL-1 and glucocorticoids on eicosanoid synthesis and provide additional support for an important role of cPLA2 in the inflammatory response.