Current View on EpCAM Structural Biology
CELLS
Authors: Gaber, Aljaz; Lenarcic, Brigita; Pavsic, Miha
Abstract
EpCAM, a carcinoma cell-surface marker protein and a therapeutic target, has been primarily addressed as a cell adhesion molecule. With regard to recent discoveries of its role in signaling with implications in cell proliferation and differentiation, and findings contradicting a direct role in mediating adhesion contacts, we provide a comprehensive and updated overview on the available structural data on EpCAM and interpret it in the light of recent reports on its function. First, we describe the structure of extracellular part of EpCAM, both as a subunit and part of a cis-dimer which, according to several experimental observations, represents a biologically relevant oligomeric state. Next, we provide a thorough evaluation of reports on EpCAM as a homophilic cell adhesion molecule with a structure-based explanation why direct EpCAM participation in cell-cell contacts is highly unlikely. Finally, we review the signaling aspect of EpCAM with focus on accessibility of signaling-associated cleavage sites.
Hashimoto's thyroiditis impairs embryo implantation by compromising endometrial morphology and receptivity markers in euthyroid mice
REPRODUCTIVE BIOLOGY AND ENDOCRINOLOGY
Authors: Wu, Zhangbi; Cai, Yaojun; Xia, Qin; Liu, Tiantian; Yang, Hao; Wang, Fen; Wang, Nan; Yu, Zhen; Yin, Chunying; Wang, Qunan; Zhu, Defa
Abstract
Background Although thyroid dysfunction caused by Hashimoto's thyroiditis (HT) is believed to be related to implantation failure due to the underdevelopment of the receptive uterus, it is unknown whether HT itself, even in the euthyroid state, impairs embryo implantation associated with endometrial receptivity defects. To address whether HT itself can affect endometrial receptivity accompanied by implantation alterations, a euthyroid HT model was established in mice. Methods Female NOD mice were immunized twice with thyroglobulin and adjuvant to induce the experimental HT model. Four weeks after the second treatment, the mice were normally mated, and pregnant ones were sacrificed in implantation window for thyroid-related parameter and steroid hormones measurements by electrochemiluminescence immunoassay and enzyme-linked immunosorbent assay and implantation site number calculation by uptake of Chicago Blue dye. In addition, certain morphological features of endometrial receptivity were observed by hematoxylin-eosin staining and scanning electron microscopy, and the expression of other receptivity markers were analyzed by immunohistochemistry, RT-qPCR or Western Blot. Results HT mice displayed intrathyroidal monocyte infiltration and elevated serum thyroid autoantibody levels without thyroid dysfunction, defined as euthyroid HT in humans. Euthyroid HT resulted in implantation failure, fewer pinopodes, retarded pinopode maturation, and inhibited expression of receptivity markers: estrogen receptor alpha (ER alpha), integrin beta 3, leukemia inhibitory factor (LIF), and cell adhesion molecule-1 (ICAM-1). Interestingly, despite this compromised endometrial receptivity response, no statistical differences in serum estradiol or progesterone level between groups were found. Conclusions These findings are the first to indicate that HT induces a nonreceptive endometrial milieu in the euthyroid state, which may underlie the detrimental effects of HT itself on embryo implantation.