Estradiol and Progesterone Increases First Trimester Trophoblast Tube Formation Through LPA3 Receptor.

RIBEIRO ML; BELTRAME JS; SORDELLI MS; CAÑUMIL VA

San Diego

Congreso; 65th Annual Meeting of the Society for Reproductive Investigation; 2018

Society for Reproductive Investigation

INTRODUCTION: Remodeling of the spiral arteries by the trophoblast is crucial during human implantation. Lysophosphatidic acid (LPA) is a lipid mediator that regulates female reproductive functions and plays an important role during angiogenesis. Previously, we observed that LPA enhances first trimester trophoblast tube formation via LPA3, the main LPA receptor involved in female reproductive physiology. Estradiol (E2) and progesterone (P4) are the master hormones at implantation and regulate trophoblast behavior. Therefore, we studied if E2 and P4 modulate the participation of LPA3 in trophoblast tube formation.METHODS: First trimester trophoblast cells (HTR-8/SVneo line) were seeded on a reduced growth factor basement membrane matrix (Geltrex), incubated with E2 (10-7, 10-8, 10-9 and 10-10 M) and/or P4 (10-5, 10-6, 10-7 and 10-8 M), in the presence of a selective LPA3 antagonist (DGPP 10-4 M), a selective LPA1 antagonist (BMT 10-5 M), or a non-selective LPA antagonist (8 Br-LPA 5.10-6 M that antagonizes LPA1, 2, 3 and 4 receptors). Cells were assayed for tube formation during 6h. Tubule length and the number of branches were calculated. The expression of LPA3 mRNA was determined by real time PCR.RESULTS: We observed that both E2 and P4 exerted a concentration-response effect. The incubation with E2 (10-8 M) or with P4 (10-7 M) separately increased tube formation of HTR-8/SVneo cells (p<0.05). The co-incubation of E2 or P4 with DGPP or 8 Br-LPA completely blocked the increase of both steroid hormones when incubated separately. BMT did not change E2 or P4 stimulatory effect. Surprisingly, when we incubated trophoblast cells with E2 (10-8 M) and P4 (10-7 M) together we did not observe any effect on tube formation. Thus, we tested different combinations of E2+P4 concentrations. We observed that only E2 (10-5 M) plus P4 (10-7 M) increased trophoblast tubulogenesis (p<0.05), and that this action was reverted by DGPP, the selective LPA3 antagonist. Finally, the expression of LPA3 mRNA was not regulated by E2 (10-5 M) + P4 (10-7 M).CONCLUSION: Collectively our results suggest that E2 and P4 increase first trimester trophoblast tube formation through LPA3 receptor. Extravillous trophoblast cells are crucial in uterine vascular remodeling, and aberrant angiogenesis due to failures in LPA3 regulation may contribute to obstetric complications such as implantation failure and preeclampsia.