Effect of primary human endometrial stromal cells on epithelial cell receptivity and protein expression is dependent on menstrual cycle stage

Abstract

Background Successful implantation requires a receptive endometrium. We hypothesized that effects of endometrial stromal cells (ESC) on epithelial cell receptivity and trophoblastendometrium interaction are menstrual cycle dependent. Methods An endometrial in vitro 3D co-culture model of primary human ESC with the endometrial epithelial cell line (RL95-2) was constructed. Co-cultures were prepared using primary ESC from biopsies taken before the window of implantation (ESCbw) and during the window of implantation (ESCw), on cycle days 1017 and 1923, respectively. RL95-2 served as a constant parameter upon which the influence of ESC from different phases of the cycle was investigated. proMMP-2 (MMP, matrix metalloproteinase) and proMMP-9 secretion was tested in response to progesterone. Progesterone receptor B (PR-B) and plexin B1 protein expression and mRNA levels were investigated using immunofluorescence and RTPCR, respectively. Results Progesterone increased proMMP-2 secretion in primary ESCbw (P 0.0046) but decreased proMMP-2 and proMMP-9 secretion in ESCw (P < 0.0005). In the presence of ESCbw, JAR spheroid attachment rate to overlying RL95-2 cells was decreased (P < 0.0001), whereas in the presence of ESCw, attachment rate was unchanged. Progesterone treatment restored epithelial cell receptivity in co-culture with ESCbw (P 0.00004). A correlation between spheroid attachment rate and plexin B1 mRNA level was observed (P 0.01). PR-B protein and mRNA level were influenced by the interplay between RL95-2 and stromal cells. Conclusion The effects of human primary ESC on epithelial cell receptivity and trophoblastendometrium interaction depended upon whether the ESC were taken before or during the window of implantation. © 2010 The Author.