Expression And Regulation Of CLEC-2 And Podoplanin At Human Maternal-fetal Interface In The First-trimester Pregnancy

At the beginning of pregnancy, decidua together with trophoblasts constitute the human maternal-fetal interface. The biological behavior of trophoblast is something like malignant tumor cells, especially in the early pregnancy. Human embryo implantation begins from the intravillus trophoblast invading into uterus endometrium and matrix under basilar membrane. After disintegrating and proliferating, introvillus trophoblast, differentiated as extravillus trophoblast, which invading deeply into maternal decidua and replacing the vascular endothelial cell of uterus spiral artery to fix placenta and fetus, remodel uterus vascular system, and provide abundant blood supply and nutrition for the developing embryo. The invasiveness of trophoblast is highly important for blastula implantation, placenta development, and the establishment of maternal-fetal circulation. The invasive abnormity of the trophoblast and abnormal remodeling of uterus spiral artery are the main reason causing pre-eclampsia, fetal growth restriction and spontaneous abortion. Therefore, the invasiveness of trophoblast has always been deeply concerned by reproductive medicine workers.The process of embryo implantation involves complex and timed molecule and cell interaction between uterus and the placenta. Trophoblast invading into endometrium is regulated by trophoblast itself, and maternal-fetal microenvironment, such as various kinds of cytokines, and pregnancy-associated hormone. There are high-level of estrogen, progesterone and hCG in the pregnancy. Progesterone and hCG can up-regulate the invasiveness of trophoblast, but the mechanisms remain unclear so far .CLEC-2, a member of C-type lectin-like receptor family, is a 33-kDa type II transmembrane glycoprotein. Initially, CLEC-2 was considered locally expressing on platelet, but there is expression of CLEC-2 on human megalokaryocyte and murine peripheral blood neutrophi. Rhodocytin and HIV are exogenous ligands of CLEC-2, and Rhodocytin can activate CLEC-2 ITAM-like motif in cytoplasmic domain, triggering cell activation when binding to CLEC-2 extracellular domain, which leads to platelet aggregation. HIV interaction with CLEC-2 may promote the migration of HIV-1. CLEC-2 may regulate the homeostasis by recognizing endogenous ligand. Podoplanin is an identified endogenous ligand of CLEC-2.As to now, we don't know if CLEC-2 is relative to pregnancy. Our research is to investigate the expression regulation of podoplanin and its receptor CLEC-2 at the maternal-fetal interface.Part 1 Expression of CLEC-2 and podoplanin at human maternal-fetal interface in the first-trimester pregnancyObjective To found out the expression of CLEC-2 and podoplanin at normal and abortive maternal-fetal interface in the first-trimester pregnancy. Methods Human normal and abortive villus and decidua were collected, and then detected for the expression of CLEC-2 and podoplanin by using immunohistochemistry, immunocytochemistry and western blot. Results CLEC-2 and podoplanin are expressed in villus, decidua, primary trophoblasts, primary decidual stromal cell (DSC), and trophoblast cell-line HTR-8/SVneo. CLEC-2 expression is lower significantly in miscarriage villus than that of the normal pregnancy, while podoplanin expression is higher in the abortive villus. However, no difference was found in normal and miscarriage decidua. Conclusion CLEC-2 and podoplanin are expressed at maternal-fetal interface in the first-trimester pregnancy, which suggests that CLEC-2 and podoplanin may be involved in the cross-talking of molecules at human maternal-fetal interface in the first-trimester pregnancy. Part 2 The regulation of CLEC-2 expression in trophoblast cell-line HTR-8/SVneoObjective To investigate regulation of the pregnancy-associated hormone on the expression of CLEC-2 in trophoblast cell-line HTR-8/SVneo. Methods HTR-8/SVneo was treated by different concentration of hCG, progesterone or estrogen, respectively, and the expression of CLEC-2 was detected by using western blot. Results Compare with control group, hCG up-regulates the expression of CLEC-2;in contrast, CLEC-2 expression in HTR-8/SVneo is down-regulated by estrogen, but progesterone has no effect on the expression of CLEC-2. Conclusion The expression of CLEC-2 in trophoblast cell-line HTR-8/SVneo is regulated by hCG and estrogen, CLEC-2 may be involved in the regulation on trophoblast invasion in human first trimester pregnancy.