Blockade NF-κB Activation Prohibits TNF-α-induced Cyclooxygenase-2 Gene Expression in ED27Trophoblast-like Cells

• Published in: Placenta (Eastbourne) 2001-01, Vol.22 (1), p.80-89
• Main Authors: Kniss, D.A., Rovin, B., Fertel, R.H., Zimmerman, P.D.
• Format: Article
• Language: English
• ISSN: 0143-4004; 1532-3102
• DOI: 10.1053/plac.2000.0591

Among the many functions of trophoblast cells is the production of prostaglandins (PGs) for governing several fetoplacental vascular functions during gestation and the triggering of events leading to parturition. Recent evidence suggests that pro-inflammatory cytokines such as tumour necrosis factors (TNF-α) induce PG formation via cyclooxygenase-2 (COX-2), a highly inducible enzyme whose gene is regulated at least in part by inducible transcription factor NF-κB. To examine the mechanism by which COX-2-driven PG biosynthesis occurs in trophoblast cells, we utilized the immortalized trophoblast-like cell line ED27. These cells exhibit many of the properties of villous or extravillous trophoblasts and produce large amounts of PGs in response to TNF-α. We demonstrated that challenge of ED27cells with TNF-α caused binding of the NF-κB complex to its κB site followed by increased accumulation of COX-2 transcripts. In addition, the inhibitor of NF-κB, IκB-α, became phosphorylated and was rapidly degraded in cytokine-treated cells; this process was abolished by co-incubation with the proteasome inhibitor, MG-132. Finally, when cells were pre-incubated with MG-132 and then challenged with TNF-α, PG formation was attenuated in a concentration-dependent manner. These data indicate that, in ED27trophoblast-like cells isolated from the first-trimester placenta, TNF-α treatment leads to activation of NF-κB and subsequent transcription of the COX-2 gene.