Differential Effects of p-Nitrophenyl-D-Xylosides on Mouse Blastocysts and Uterine Epithelial Cells1

Abstract

A number of studies have implicated glycoconjugates in cell recognition events associated with implantation of mammalian blastocysts into the uterus. We have found that p-nitrophenyl-D-xylosides inhibit mouse embryo attachment and outgrowth on monolayers of uterine epithelial cells when cocultured in vitro. Inhibition of attachment and trophoblast formation by alpha- and beta-xylosides was observed in embryos cultured on tissue culture plastic in serum containing medium or on monolayers of epithelial cells. The biochemical basis for this inhibition has been investigated. Consistent with their accepted mode of action, beta- but not alpha-D-xylosides greatly stimulated glycosaminoglycan chain production by uterine epithelial cells and likewise reduced proteoglycan assembly. In contrast, both alpha- and beta-anomers selectively inhibited embryo attachment and outgrowth without stimulating glycosaminoglycan chain production by embryos. The inhibitory effect of the xylosides on embryos was reversible and did not require concentrations that reduced the rate of protein synthesis. Both alpha- and beta-D-xylosides inhibited the synthesis of proteoglycans including heparan sulfate as well as certain other glycoconjugates by embryos. Collectively, these data indicate that proper assembly of glycoconjugates, including proteoglycans, is required for implantation-related processes, although the inhibition of embryo outgrowth by xylosides may be by an as yet uncharacterized mechanism.

Cell Surface Expression of HIP, a Novel Heparin/Heparan Sulfate-binding Protein, of Human Uterine Epithelial Cells and Cell Lines

“…Furthermore, blastocyst attachment to laminin, fibronectin, and isolated mouse uterine epithelial cells is inhibited by HP. Embryo attachment also is inhibited by the treatment of embryos with HP/HS lyases or inhibitors of proteoglycan biosynthesis (10,11). Immunological studies of murine embryo implantation sites indicated that the core protein of the basement membrane HSPG, perlecan, and HP/HS chains are located between the apical cell surfaces of trophectodermal cells and uterine epithelial cells during the peri-implantation stage (12).…”

A Peptide Sequence of Heparin/Heparan Sulfate (HP/HS)-interacting Protein Supports Selective, High Affinity Binding of HP/HS and Cell Attachment

“…HSPGs can be detected as early as the two-cell stage (10), and HSPG expression on cell surfaces of mouse blastocysts increases 4 -5-fold at the peri-implantation stage (11)(12)(13). Inhibition of HSPG synthesis or enzymatic removal of HS from blastocyst surfaces inhibits embryo attachment (12,14). Mouse embryo attachment to fibronectin, laminin, and isolated mouse uterine epithelial cells is HP/HSdependent (11).…”

The heparin-binding domain of HB-EGF mediates localization to sites of cell-cell contact and prevents HB-EGF proteolytic release

“…HSPGs have previously been shown to interact in trans with VEGFR-2 in VEGFR-mediated angiogenesis (Jakobsson et al, 2006) and with the Xenopus receptor caALK4 via the cofactor Vg1 during mesoderm migration in early left-right development (Kramer and Yost, 2002). Additionally, this interaction probably plays a role in blastocyst implantation during pregnancy, because the interaction between HB-EGF on the lumenal epithelium with EGFR and HSPGs on the adjacent blastocyst is required for successful attachment, which is reduced by exogenous heparin or blastocyst heparinase treatment (Farach et al, 1987;Farach et al, 1988;Raab et al, 1996).…”