No abstract

Embryo implantation in the uterus is an essential process for successful pregnancy in mammals. In general, the endocrine system induces sufficient embryo receptivity in the endometrium, where adhesion-promoting molecules increase and adhesion-inhibitory molecules decrease. Although the precise mechanisms remain unknown, it is widely accepted that maternal–embryo communications, including embryonic signals, improve the receptive ability of the sex steroid hormone-primed endometrium. The embryo may utilize repulsive forces produced by an Eph–ephrin system for its timely attachment to and subsequent invasion through the endometrial epithelial layer. Importantly, the embryonic signals are considered to act on maternal immune cells to induce immune tolerance. They also elicit local inflammation that promotes endometrial differentiation and maternal tissue remodeling during embryo implantation and placentation. Additional clarification of the immune control mechanisms by embryonic signals, such as human chorionic gonadotropin, pre-implantation factor, zona pellucida degradation products, and laeverin, will aid in the further development of immunotherapy to minimize implantation failure in the future.

Our results suggest the involvement of peritoneal versican in the development of peritoneal endometriosis.

These findings suggest that Eph-ephrin interaction plays some role in the regulation of choriocarcinoma invasion in cooperation with integrins.

The endometrium extracellular matrix (ECM) is essential for embryo implantation. Versican, a large chondroitin sulfate proteoglycan that binds hyaluronan and forms large ECM aggregates, can influence fundamental physiological phenomena, such as cell proliferation, adhesion and migration. The present study investigated the possible role of versican in human embryo implantation. Versican V1 expression and secretion in human endometrial epithelial cells (EECs) was most prominent in the mid-secretory phase. Versican expression in EECs significantly increased after treatment with estrogen and progesterone, but not by estrogen alone. We also established versican V1-overexpressing Ishikawa (endometrial cancer cell line) cells (ISKW-V1), versican V3-overexpressing (ISKW-V3) and control GFP-overexpressing (ISKW-GFP) Ishikawa cells. By the in vitro implantation model, the attachment ratio of BeWo (choriocarcinoma cell line) spheroids to the monolayer of ISKW-V1, but not of ISKW-V3, was found significantly enhanced compared with attachment to the ISKW-GFP monolayer. The conditioned medium derived from ISKW-V1 (V1-CM) also promoted the attachment of BeWo spheroids to the ISKW monolayer. However, this attachment-promoting effect was abolished when V1-CM was pretreated with chondroitinase ABC, which degrades chondroitin sulfate. Therefore, out of the ECM components, versican V1 may facilitate human embryo implantation.Reproduction (2019) 157 53-64