213. Chemokines: key players at the maternal-fetal interface

Abstract

Establishment of pregnancy requires extensive communication at the maternal-fetal interface and involves a plethora of locally acting molecules, including the chemokines. Chemokines are multifunctional molecules initially described for roles in leukocyte trafficking, but since found to participate in many other processes such as differentiation and directed migration. Previously we have shown that the chemokines, CX3CL1 and CCL14, are abundant in human endometrial vasculature, leukocytes, epithelial and decidual cells at the time of implantation and that their receptors, CX3CR1 and CCR1, are present on invading human trophoblast. CX3CL1 and CCL14 directly promote human trophoblast migration. We hypothesised that these endometrial chemokines promote trophoblast migration by regulating adhesion molecules and extracellular matrix (ECM) components on the trophoblast, similar to mechanisms used in leukocyte trafficking. Trophoblast cells (AC1M-88) used previously, showed a marked increase in adhesion to fibronectin following treatment with CX3CL1 and CCL14. Alterations in trophoblast adhesion associated and ECM genes following chemokine stimulation were examined using pathway specific oligo-arrays and quantitative real-time RT–PCR. Over 30 transcripts were affected by CX3CL1 treatment and 15 were regulated by CCL14 treatment. Real-time RT–PCR confirmed significant changes in the mRNA transcripts of α-catenin (CTNNA1), extracellular matrix protein-1 (ECM1), osteopontin (SPP1), integrin α6 (ITGA6), matrix metalloproteinase-12 (MMP12) and integrin β5 (ITGB5) following chemokine treatment. Several of these molecules have previously been implicated in implantation. Immunohistochemistry confirmed the presence of integrin α6, SPP1 and ECM1 protein in first trimester human implantation sites. The temporal and spatial expression of chemokines, their receptors and adhesion related molecules at the maternal-fetal interface emphasises an important role in the controlled directional migration of trophoblast through the maternal decidua. For the first time this study demonstrates direct effects of CX3CL1 and CCL14 on trophoblast adhesion and ECM molecules suggesting mechanisms by which trophoblast cells migrate during early pregnancy.