Cross-talk between trophoblastic cells and maternal immune cells coordinated by Ccl25 Ccr9 during mouse embryo implantation

Abstract

Background: CC’ and CXC’terminal chemokines are known to be involved with the polarity of blastocyst and uterus, leukocyte recruitment and capture/coordination of leukocyte migration. Particularly the chemokine CCL25 is expressed by the mouse trophoblast cells during implantation phase. Objectives: The aim of this study is to investigate the expression and localization of Ccl25 and its receptor Ccr9 during the mouse embryo implantation period. Methodology: Ccl25 and Ccr9 transcript abundance was measured by qPCR on fl ushed blastocyst from gestation days (gd) 3.5, 4.5, 5.5 and 7.5 and protein by immunofluorescence on frozen sections of implantation sites and on fl ushed blastocyst from gd4.5, 5.5 and 7.5. Results: Blastocyst expression of Ccl25/Ccr9 mRNA increased on gd4.5 and 5.5 and 7.5. Ccl25 was immunolocalized at trophoblast cells surrounding the blastocyst and glandular and uterine luminal epithelial cells, while Ccr9 was expressed at leukocytes inside maternal vessels surrounding the implanting embryo. Conclusion: Expression of chemokine /receptor during blastocyst implantation suggests a role and likely a cross-talk between trophoblast cells and the maternal immune cells and adds new elements to the understanding of trophoblast interactions during embryo implantation.