Human endometrial MUC1 carries keratan sulfate: characteristic glycoforms in the luminal epithelium at receptivity

Abstract

MUC1 is a high molecular mass, highly glycosylated epithelial apical glycoprotein that has been shown to exhibit both adhesive and anti-adhesive properties. Its expression in human glandular endometrial epithelium is transcriptionally regulated with the highest levels in the mid secretory phase, the "receptive" period during which implantation occurs. We demonstrate that endometrial MUC1 carries highly sulfated lactosaminoglycan chains recognized by monoclonal antibody (Mab) 5D4, and the sialokeratan sulfate epitope recognized by Mab D9B1. These glycans are hormonally regulated in endometrium, and show increased abundance in the secretory phase, but detailed evaluation of their distribution shows important differences. The 5D4 epitope is abundant at the luminal epithelial surface until the implantation phase, when it disappears, first from patches of cells, then altogether. D9B1 binding sites are retained in the luminal epithelium at receptivity. These data show that endometrial MUC1 carries sulfated lactosaminoglycans. They identify the luminal epithelial compartment as a site of unique MUC1 glycosylation and independent regulation. Glycosylation and the negative charge associated with sialo- and sulfoglycans may be important in the regulation of embryo attachment.

Effect of low-dose mifepristone administration on day 2 after ovulation on transcript profiles in implantation-stage endometrium of rhesus monkeys

“…Relative abundance of transcripts for prolactin receptor and mucin became lower in mifepristone-treated endometrium on days 4 and 6 respectively after ovulation, compared with control endometrium. These factors are known to be regulated in endometrium by progesterone (Salamonsen & Woolley 1996, Aplin et al 1998, Nayak et al 1998, Kim et al 1999, Marions & Gemzell-Danielsson 1999, Tseng & Mazella 1999, Milne & Jobbour 2003, Lalitkumar et al 2005a, 2005b, Stavreus-Evers et al 2005, Critchley et al 2006, Goff et al 2006, Slayden & Brenner 2006, Makino et al 2007. It may be conjectured that significant changes in the expression of these factors are involved in endometrial hostility in mifepristonetreated endometrium.…”

Golgi Localization of Carbohydrate Sulfotransferases Is a Determinant of L-selectin Ligand Biosynthesis

“…1B), but the antibody also binds 6-sulfosialylLacNAc, which lacks fucose, with lower affinity (43). This latter epitope is a capping group that has been observed on keratan sulfate chains and various glycoproteins (23,44,45).…”

Continuous model of conceptus implantation to the maternal endometrium

“…Cell-cell interactions between the conceptus and endometrium have also been documented to be critical for successful implantation in humans and murine species (Aplin et al 1998, Armant 2005, in which the extracellular domain of ITGs acts as a receptor for extracellular matrix components (ECMs) such as fibronectin, vitronectin, laminin, collagen-type IV and osteopontin (SPP) (Akiyama 1996, MacIntyre et al 2002. In goats, sheep, and cattle, constituents of uterine histotroph such as CXCL10, LGALS15 and IGFBP1 have been characterized to activate ITGs through their RGD domain during the period of TE cell attachment to the uterine epithelium (Akiyama 1996, Aplin et al 1998, Nagaoka et al 2003b.…”

“…In goats, sheep, and cattle, constituents of uterine histotroph such as CXCL10, LGALS15 and IGFBP1 have been characterized to activate ITGs through their RGD domain during the period of TE cell attachment to the uterine epithelium (Akiyama 1996, Aplin et al 1998, Nagaoka et al 2003b. In particular, the expression of ITGs has been characterized at the uteroplacental interface during the periods of bovine TE attachment (MacIntyre et al 2002, Pfarrer et al 2003 and placentation (Pfarrer 2006).…”