Background: The invasion of first trimester extravillous trophoblast (EVT) to decidua is an important event in placentation. Leukemia inhibitory factor (LIF) is an essential factor for mouse implantation, and it is reported that LIF may be involved in human first trimester EVT invasion. Prostaglandin E2 (PGE2) is also known as a critical factor for first trimester EVT invasion. In this study, we investigated the role of LIF in PGE2 production and EVT invasion using a human first trimester EVT cell line, HTR-8/SVneo.
Methods and results: Co-stimulation with LIF and IL-1beta induced higher amounts of PGE2 production and further migration of HTR-8/SVneo cells compared with that by stimulation with LIF or IL-1beta alone. Enhanced PGE2 production was most probably due to the enhanced expression of cyclooxygenase-2 (COX-2) and microsomal PGE synthase-1 (mPGES-1). PGE2 produced by HTR-8/SVneo cells promoted the migration of HTR-8/SVneo cells. A COX-2 inhibitor suppressed PGE2 production and the migration of HTR-8/SVneo cells. Agonists to PGE2 receptors, EP1, EP2 and EP4, promoted the migration of HTR-8/SVneo cells. Moreover, stimulation with LIF up-regulated EP1, EP2 and EP4 expression in HTR-8/SVneo cells.
Conclusions: It is suggested that LIF participates in placentation through EVT invasion by up-regulating PGE2 production and PGE2 receptor expression in first trimester EVT.