INDUCTION OF PROSTAGLANDIN-H SYNTHASE-2 AND TUMOR-NECROSIS-FACTOR-ALPHA IN HUMAN AMNIOTIC WISH CELLS BY VARIOUS STIMULI OCCURS THROUGH DISTINCT INTRACELLULAR MECHANISMS

These studies examined the signal transduction mechanisms by which pro staglandin (PG) E(2) production can occur in human amnionic WISH cells in response to the stimuli okadaic acid, interleukin (IL)-1 beta, tum or necrosis factor (TNF)-alpha, phorbol-12-myristate-13-acetate (PMA) or combinations of PMA with IL-1 beta or TNF-alpha. We also investigat ed whether WISH cells are capable of producing TNF-alpha or IL-1 beta in response to stimulation, because these cytokines can be produced in an autocrine fashion to perpetuate an inflammatory response. Our data indicate that the magnitude of PGE(2) production induced by a given s timulus correlated temporally with the level of PGH synthase-2 (PGHS-2 ) protein. PMA or IL-1 beta induced PGE(2) production 2 to 4 hr after treatment, whereas the combination of these agents produced the most r apid induction 2 hr after treatment. Only okadaic acid induced the pro duction of both PGE(2) and TNF-alpha after a lag of 12 to 18 hr. PGE(2 ) production by all stimuli was inhibited by dexamethasone, the IL-1 r eceptor antagonist (IL-1ra), the specific PGHS-2 inhibitor NS-398 and the protein kinase inhibitor staurosporin. In contrast, TNF-alpha prod uction in response to okadaic acid was inhibited by the TNF-converting enzyme inhibitor GI 129471 and staurosporin but was unaffected by eit her IL-1ra, dexamethasone or NS-398. We conclude that WISH cells are c apable of producing bioactive proinflammatory mediators such as TNF-al pha and PGE(2) through separable intracellular signal transduction mec hanisms. The ability of IL-1ra to reduce PGE(2) production caused by a ll stimuli used suggests an autocrine role for IL-1 in PGHS-2 inductio n in these cells.