|M.Sc Student||Evron Ayelet|
|Subject||Molecular Mechanisms in Maternal-Trophoblast Interaction|
|Department||Department of Medicine||Supervisor||Professor Emeritus Eliezer Shalev|
|Full Thesis text|
The importance of epithelial-stroma interactions under the influence of ovarian steroids in the acquisition of endometrial epithelial receptivity is widely recognized. We hypothesized that primary endometrial stromal cells differentially affect epithelial cell receptivity and trophoblast-endometrium interaction. For this, we constructed an endometrial in vitro 3D co-culture model of primary endometrial stromal cells with the high receptive endometrial epithelial adenocarcinoma cell line RL95-2. The first co-culture was constructed with primary endometrial stromal cells from cycle days 10-17 (before the window of implantation) and the second with stromal cells from cycle days 19-23 (at the window of implantation). In this alternative 3D co-culture model the epithelial cell line RL95-2 served as a constant parameter on which the influence of stromal cells from different phases of the menstrual cycle was investigated. ProMMP-2 and proMMP-9 secretion were tested in a dose response experimental setting to progesterone and to GnRH Agonist. Progesterone increased proMMP-2 secretion in primary stromal cells before window of implantation, but decreased proMMP-2 and proMMP-9 secretion in primary stromal cells from the window of implantation. In the co-cultures with RL95-2 cells the influence of progesterone on proMMPs secretion was abolished. GnRH Agonist increased proMMPs secretion in all endometrial cell cultures. In the co-culture with RL95-2 cells the influence of GnRH Agonist on proMMPs secretion was enhanced. Using JAR spheroid attachment assay, in the co-culture of primary stromal cells before window of implantation to overlying RL95-2 cells, decreased JAR spheroid attachment rates were observed. Treatment of this co-culture with progesterone or with GnRH Agonist restored epithelial receptivity. In the co-culture with primary stromal cells from the window of implantation, significant higher JAR spheroid growth was observed under all treatment conditions compared to co-cultures with primary stromal cells before window of implantation, but no change was observed in the spheroid attachment rates. Low Plexin B1 protein distribution was observed in co-culture with stromal cells before window of implantation. Progesterone treatment significantly increased PB-1 gene expression and protein distribution in this co-culture. Epithelial-stroma interaction was found also to change the distribution ratio of progesterone receptor isoforms that may affect progesterone responsiveness of endometrial cells. We can conclude that primary endometrial stromal cells differentially affect epithelial cell receptivity and trophoblast-endometrium interaction. Further more it seems from our results that high levels of PR-B and low levels of PB-1 may be responsible for low trophoblast attachment to endometrial epithelial cells.