Biosynthesis and distribution of Lewis X- and Lewis Y-containing glycoproteins in the murine male reproductive system.

Although Lewis X (LeX) and Lewis Y (LeY) antigens were thought to play important roles in fertility, fucosyltransferase (Fut)-deficient (Fut1, Fut2 and Fut4) mice which lack LeX or LeY antigen are still fertile. In the present study, the Fut-deficient and wild-type mice were used to measure the expression of Fut mRNA along the mouse male reproductive tract and determine the role of each Fut in the biosynthesis of LeX/LeY antigens, which are conjugated to glycoproteins in the male reproductive system. LeX/LeY-containing glycoproteins were detected in the epididymis, vas deferens, seminal vesicle and coagulating gland, but not in the testis. We demonstrate that the synthesis of LeY-containing glycoproteins in the epididymis and vas deferens is catalyzed by Fut1 and Fut4. In the seminal vesicle and the coagulating gland, they are mainly synthesized by Fut2 and an α-(1,3)-Fut, but not Fut4. The synthesis of LeX-containing glycoproteins in the middle caput epididymis is catalyzed by Fut4 and by Fut4 and Fut2 in the seminal vesicle. We provide evidence that LeX is synthesized in the coagulating gland by Fut9. We found that the lack of activity by one Fut does not completely inhibit LeX/LeY antigen expression in the male reproductive tract. This redundancy may help to explain why in vivo studies with Fut-deficient mice do not support the presumption that LeX/LeY antigens play important roles in male fertility. We provide details regarding the phenotypes of established Fut-deficient mice and lay the foundation for elucidating the functions of LeX/LeY antigens in other aspects of the male reproductive system.

LeY oligosaccharide upregulates DAG/PKC signaling pathway in the human endometrial cells.

LeY oligosaccharide is stage specifically expressed by the embryo and uterine endometrium, and it plays important roles in embryo implantation. In addition to participating in the recognition and adhesion on fetal-maternal interface, LeY potentially regulates the expression of some implantation-related factors. However, it remains elusive whether it can mediate the involved signaling pathway. In this study, agarose-LeY beads were used to mimic the embryos, and the effects of LeY oligosaccharide on DAG/PKC signaling pathway was studied in human endometrial epithelial cells. Results showed that LeY could significantly trigger the activation of cPKCalpha and cPKCbeta2, and their translocation from the cytosol to the plasma membrane. The cellular DAG content was also upregulated, and the activation of PLCgamma1 was promoted. On the contrary, DAG/PKC signaling pathway was significantly inhibited when anti-LeY antibody was used after confirmation of LeY expression in human endometrial epithelial cells by immunohistochemistry and flow cytometry. These results suggest that LeY oligosaccharide acts as a signal molecule to modulate DAG/PKC signaling pathway.

[Effects of blastocyst surface oligosaccharide LeY on secretion and expression of matrix metalloproteinase in vivo].

The effects of oligosaccharide LeY on expression and secretion of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase 1 (TIMP1) of embryos were investigated in cultured mouse blastocysts by zymography, immuno-dot blots and RT-PCR after blocking the oligosaccharide on embryo surface with specific monoclonal antibody AH6. The cultured blastocysts were treated with antibody AH6 for 3 h, then the antibody was removed and culture was continued, and the expression and secretion of MMP and TIMP1 were analyzed at 1.5 h, 3 h and 6 h. It was shown that, only 1.5 h after blocking, the expression of MMP2 gene and MMP9 gene in embryo was significantly declined, and expression of TIMP1 was slight increased, then secretions of MMP2, MMP9 were also declined at 3 h, but secretion of TIMP1 had no significant change during the period of observation. The results indicate that LeY may play a role of regulating the expression and secretion of MMP of mouse embryo at pre-implantation stage, by controlling the expression of MMP2 gene and MMP9 gene.

Ovary Hormonal Control of Le(y) Oligosaccharide Expression during Peri-implantation of Mouse Endometrium.

It has been reported that oligosaccharide Le(y) plays an essential role at the initial stage of implantation. It may act as a mediator molecule for recognition and adhesion between the surface of blastocysts and epithelial cells. Alpha 1,2 fucosyltransferase (FUT1) and alpha1,3 fucosyltransferase (FUT4) are responsible for the synthesis of its alpha1,2 and alpha1,3 fucose, respectively. In this article, the transcription of FUT1 and FUT4 genes was investigated by semi-quantitative RT-PCR and the expression of Le(y) oligosaccharide was analysized by Western blotting and immunohistochemistry with the endometrium of early pregnancymice and of the mice treated by ovary hormones after ovariectomy, in order to investigate the regulation of ovary hormones on the Le(y) oligosaccharide antigen expression. The results showed that the transcription level of FUT1 and FUT4 genes decreased during early pregnancy through days 1--5, which was in agreement with the increasing level of progesterone. In the ovariectomized group, the transcription level of the genes decreased significantly after progesterone treatment and increased after estrogen treatment, and was at the intermediate level in the group treated with both hormones. The biosynthesis of Le( y ) oligosaccharide paralleled with the transcription of FUT 1 and FUT4 gene. These results suggest that the expression of Le(y) oligosaccharide in the endometrial epithelium of mice is regulated at the level of transcription of FUT1 and FUT4 genes. It is suppressed by progesterone and stimulated by estrogen, and the effects of both hormones are in antagonism.