INTERLEUKIN-1-BETA INDUCES CYCLOOXYGENASE-2 IN CULTURED HUMAN DECIDUAL CELLS

PROBLEM: The purpose of this study was to examine the hypothesis that interleukin-1 beta (IL-1 beta)-elicited increases in decidual prostaglandin E(2) and F-2 alpha (PGE(2) and PGF(2 alpha)) biosynthesis are due to the de novo expression of the inducible isoform of cyclooxygenase (i.e., COX-2). METHOD: Primary human decidual cell cultures were established from term placentas delivered by cesarean section. After 8 days in vitro, when the cultures secreted immunoreactive prolactin, the cells were incubated for 24 h in serum-free medium, and then challenged with IL-1 beta from 1 to 48 h. PGE(2) and PGF(2 alpha) content in the media were measured by specific radioimmunoassays. RESULTS: IL-1 beta stimulated a time-dependent enhancement in PGE(2) and PGF(2 alpha) production, with PGF(2 alpha) synthesis predominating over PGE(2). IL-1 beta also induced a dose-dependent increase in the output of both arachidonic acid metabolites. When Northern blots of IL-1 beta-treated and control cells were probed with cDNAs encoding either COX-1 or COX-2 isoforms or an oligonucleotide probe encoding a portion of the human beta-actin, we detected a time-and dose-dependent increase in the steady-state levels of COX-2, but not COX-1 or beta-actin mRNA transcripts. Moreover, the expression of COX-2 mRNA in IL-1 beta-stimulated cells was superinduced by preincubation with cycloheximide, but completely abolished by actinomycin D. CONCLUSIONS: Taken together, the data suggest that COX-2 mRNA expression is largely responsible for the robust increase in PG formation seen in IL-1 beta-treated decidual cells.