No abstract

Embryo implantation and decidualization are key steps for successful reproduction. Although numerous factors have been identified to be involved in embryo implantation and decidualization, the mechanisms underlying these processes are still unclear. Based on our preliminary data, Prss56, a trypsin-like serine protease, is strongly expressed at implantation site in mouse uterus. However, the expression, regulation and function of Prss56 during early pregnancy are still unknown. In mouse uterus, is strongly expressed in the subluminal stromal cells at implantation site on day 5 of pregnancy compared to inter-implantation site. Under delayed implantation, expression is undetected. After delayed implantation is activated by estrogen, Prss56 is obviously induced at implantation site. Under artificial decidualization, Prss56 signal is seen at the primary decidual zone at the initial stage of artificial decidualization. When stromal cells are induced for decidualization, expression is significantly elevated. expression under decidualization is suppressed by siRNA. In cultured stromal cells, HB-EGF markedly stimulates expression through EGFR/ERK pathway. Based on promoter analysis, we also showed that Egr2 is involved in Prss56 regulation by HB-EGF. Collectively, expression at implantation site is modulated by HB-EGF/EGFR/ERK signaling pathway and involved in mouse decidualization.

There are around 300 million adolescent pregnancies worldwide, accounting for 11% of all births worldwide. Accumulating evidence demonstrates that many adverse perinatal outcomes are associated with adolescent pregnancies. However, how and why these abnormalities occur remain to be defined. In this study, pregnancy at different stages were compared between 25-30 day old and mature female mice. We found the litter size of adolescent pregnancy is significantly decreased from F1 to F3 generations compared to mature pregnancy. On days 8 and 12 of pregnancy, multiple abnormalities in decidual and placental development appear in F3 adolescent pregnancy. On days 5 and 8, uterine endoplasmic reticulum stress is dysregulated in F3 adolescent pregnancy. Embryo implantation and decidualization are also compromised in adolescent pregnancy. Many genes are abnormally expressed in adolescent estrous uteri. The abnormal endocrine environment and abnormal implantation from uterine immaturity may result in multiple pregnancy failures in adolescent pregnancy. This study should shed light on human adolescent pregnancy.