GRP78 expression and regulation in the mouse uterus during embryo implantation

Abstract

The aim of this study was to investigate the spatiotemporal expression and regulation of GRP78 in the mouse uterus during the peri-implantation period. The GRP78 protein was mainly detected in the luminal and glandular epithelia on days 1-4 of pregnancy. On day 5 of pregnancy, the GRP78 protein was more highly observed around the implanted embryo at the implantation site. There was no detectable GRP78 protein signal on day 5 of pseudopregnancy. GRP78 mRNA and protein levels gradually increased on days 6-8 of pregnancy, and the expression pattern was also expanded, coinciding with the development of decidua. Similarly, GRP78 expression was also strongly expressed in decidualised cells following artificial decidualisation. Compared with the results obtained with the delayed uterus, a high level of GRP78 expression was detected in the implantation-activated uterus. In the uteri of ovariectomised mice, GRP78 expression increased and reached its highest level after injection of oestrogen, and progesterone seemed to have an antagonistic effect on oestrogen up-regulation of GRP78 expression. Our data indicate that GRP78 might play an important role during the process of mouse embryo implantation, and GRP78 expression was mainly regulated by active blastocysts and maternal oestrogen.

The roles of endoplasmic reticulum stress response in female mammalian reproduction

“…However, regardless of whether ERS is initiated under physiological conditions or not, previous studies have suggested that, compared with the control, the expression of Grp78 in mouse decidual uterus does not change significantly (Simmons and Kennedy 2000), suggesting that ERS might not be involved in decidualization. In contrast, our previous studies have suggested that Grp78 is remarkably upregulated in pregnant mouse uteri at day 5 (embryo implantation has occurred) and days 6-8 (decidualization; Lin et al 2014). These results indicate that ERS might be involved in decidualization.…”

Uterine RGS2 expression is regulated by exogenous estrogen and progesterone in ovariectomized mice, and downregulation of RGS2 expression in artificial decidualized ESCs inhibits trophoblast spreading in vitro

“…We used experimental mouse models of normal pregnant mice and OVX mice, according to previous studies (Lin et al, ). The model of normal pregnancy was used to investigate the spatiotemporal expression of RGS2 in the uterus during implantation.…”

“…However, examining the direct role of RGS2 in embryonic invasion, in decidualization of ESCs, and in identifying which G-protein-coupled signaling pathways are involved in the interactions between embryo and uterus during implantation requires further investigation. We used experimental mouse models of normal pregnant mice and OVX mice, according to previous studies (Lin et al, 2014). The model of normal pregnancy was used to investigate the spatio-temporal expression of RGS2 in the uterus during implantation.…”

The Mechanism of Swainsonine Causing Early Pregnancy Abnormal Decidualization and Inducing Abortion by Changing Glycosylation Modification

“…Many ER-stress-related gene expressions change during embryo implantation, suggesting that ER stress may be an essential step in embryo implantation. On day 5 of pregnancy in mice, the GRP78 protein was more highly observed around the implanted embryo at the implantation site, and we understand that the change of GRP78 expression means the occurrence of ER stress [87]. On the other hand, calcium homeostasis can cause ER stress, and ER stress and UPR regulate calcium homeostasis [88].…”