The Effects Of FABP4 On Endometrial Epith Elium Cells

BackgroundThe establishment and maintenance of pregnancy occurs through the interaction between maternal uterine endometrium and embryo (mainly the trophoblasts).Embryo implantation is the first and crucial role of reproduction. Implantation failure is one of the main causes for early pregnancy loss. However, the molecular mechanism remains largely unknown. Our previous finding showed that fatty acid-binding protein 4 expressed in human endometrial epithelial cells and promoted proliferation, migration and invasion of epithelial cells of uterine endometrium.ObjectivesTo clarify the roles of fatty acid-binding protein 4 (FABP4) of endometrial epithelial cell in the establishment and maintenance of pregnancy, and try to clarify its involvement in the pathogenesis of pregnancy loss.MethodsReal-time quantitative polymerase-chain reaction (RT-PCR) was used to test the expression of FABP4 mRNA in the deciduas of women with early pregnancy loss and normal pregnancy. The expression of FABP4 and uterine receptive factor (leukemia inhibitory factor (LIF), Integrin-β3 and Claudin 4) was determined by Western blotting. FABP4 siRNA was used to silence FABP4 while FABP4 inhibitor was used to inhibit the function of FABP4 in endometrial epithelial cell. ICR mice were used to evaluate the effect of FABP4 silence or inhibition on embryo implantation in vivo after FABP4 siRNA mixture or inhibitor was injected into uterus, and an embryonic adhesion system using trophoblast spheroids mimicking embryos was set up to assess the effect of FABP4 silence or inhibition on embryonic adhesion onto endometrial cell in vitro.ResultsThe expression of FABP4 mRNA was significantly decreased in the deciduas of women with early pregnancy loss compared with that of women with normal pregnancy. FABP4 siRNA significantly reduced the number of embryos implanted and FABP4 expression in ICR mice. FABP4 inhibition also significantly decreased the number of embryos implanted. Either silence or inhibition of FABP4 in endometrial epithelial cell abolished the expression of uterine receptive factors induced by the combination of estrogen and progesterone, and reduced the number of trophoblast spheroids adhered onto endometrial cell.Conclusions1、Silence or inhibit FABP4 reduce the abtility of embryo implantation both in vivo and in vivtro.2、Silence or inhibit FABP4 reduce the expression of uterine receptivity factors.3、6The low level expression of FABP4 in endometrium may be the pathophysiologic changes of pregnany loss.