ABSTRACT
To achieve a successful pregnancy in humans, sperm is required for capacitation, followed by binding to and entry into an oocyte. Maternal endometrial epithelial cells (EECs) prepare the appropriate implantation environment through regulation of immune cells and endometrial cells. After acquiring endometrial receptivity, a successful pregnancy consists of complex and finely regulated steps involving apposition, adhesion, invasion, and penetration. Glycodelin is a secretory glycoprotein that affects cell proliferation, differentiation, adhesion, and motility. Glycodelin has four glycoforms (glycodelin-A, -S, -F. and -C); differences in glycosylation affect each characteristic function. Glycodelin has a unique temporospatial pattern of expression, primarily in the reproductive tract where glycodelin is mid-secretory phase-dominant. Recent studies have demonstrated that glycodelin protein has the potential to regulate various processes, including immunosuppression, fertilization, and implantation. This review details the orchestrated regulation of successful pregnancy by glycodelin as well as a discussion of the basic characteristics of glycodelin.
ABSTRACT
Human embryo implantation is a critical multistep process consisting of embryo apposition/adhesion, followed by penetration and invasion. Through embryo penetration, the endometrial epithelial cell barrier is disrupted and remodeled by an unknown mechanism. We have previously developed an in vitro model for human embryo implantation employing the human choriocarcinoma cell line JAR and the human endometrial adenocarcinoma cell line Ishikawa. Using this model we have shown that stimulation with ovarian steroid hormones (17ß-estradiol and progesterone, E2P4) and suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, enhances the attachment and adhesion of JAR spheroids to Ishikawa. In the present study we showed that the attachment and adhesion of JAR spheroids and treatment with E2P4 or SAHA individually induce the epithelial-mesenchymal transition (EMT) in Ishikawa cells. This was evident by up-regulation of N-cadherin and vimentin, a mesenchymal cell marker, and concomitant down-regulation of E-cadherin in Ishikawa cells. Stimulation with E2P4 or SAHA accelerated Ishikawa cell motility, increased JAR spheroid outgrowth, and enhanced the unique redistribution of N-cadherin, which was most prominent in proximity to the adhered spheroids. Moreover, an N-cadherin functional blocking antibody attenuated all events but not JAR spheroid adhesion. These results collectively provide evidence suggesting that E2P4- and implanting embryo-induced EMT of endometrial epithelial cells may play a pivotal role in the subsequent processes of human embryo implantation with functional control of N-cadherin.
