Objective: The effects of prostaglandin E2 (PGE2) are mediated through G-protein coupled receptors, acting via different second messengers. The aim of this study was to characterize the temporal and tissue specific localization and expression of the PGE2 receptor subtypes (EP1-4) in uteroplacental tissues during human pregnancy.
Study design: Placenta and fetal membranes were collected after delivery at preterm or term, each with or without labor. The localization and expression of the PGE2 receptor subtypes were determined by immunohistochemistry and Western blot.
Results: All 4 receptors were expressed in the placenta and fetal membranes; only EP3 was present in the syncytiotrophoblast layer. EP1 to EP4 were consistently expressed across gestation in the fetal membranes; however, a different cellular localization with labor was observed in the amnion for EP1, EP2, and EP4.
Conclusion: The presence of these receptors in the placenta and fetal membranes may indicate autocrine roles for PGE2 in the signaling pathways associated with placental function and parturition.