Characterization of secreted proteins of 2-cell mouse embryos cultured in vitro to the blastocyst stage with and without protein supplementation

MFGE8 regulates TGF-β-induced epithelial mesenchymal transition in endometrial epithelial cells in vitro

This study investigated the role of milk fat globule-epidermal growth factor-factor 8 (MFGE8) in TGF-β-induced epithelial-mesenchymal transition (EMT) of endometrial epithelial cells. These were in vitro studies using human endometrial epithelial cells and mouse blastocysts. We investigated the ability of TGF-β to induce EMT in endometrial epithelial cells (HEC-1A) by assessment of cytological phenotype (by light and atomic force microscopy), changes in expression of the markers of cell adhesion/differentiation E- and N-cadherin, and of the transcription factor Snail (by immunofluorescence and immunoblotting), and competence to support embryo attachment in a mouse blastocyst outgrowth assay. We also studied the effects of E-cadherin expression in cells transfected by retroviral shRNA vectors specifically silencing MFGE8. Results demonstrated that TGF-β induced EMT as demonstrated by phenotypic cell changes, by a switch of cadherin expression as well as by upregulation of the expression of the mesenchymal markers Snail and Vimentin. Upon MFGE8 knockdown, these processes were interfered with, suggesting that MFGE8 and TGF-β together may participate in regulation of EMT. This study demonstrated for the first time that endometrial MFGE8 modulates TGF-β-induced EMT in human endometrium cells.

Preimplantation embryo-secreted factors modulate maternal gene expression in rat uterus

In mammalian reproduction, embryo implantation into the uterus is spatiotemporally regulated by a complex process triggered by a number of factors. Although previous studies have suggested that uterine receptivity is mediated by blastocyst-derived factors, specific functions of embryos remain to be defined during preimplantation. Therefore, the present study was conducted to identify the maternal genes regulated by embryo-secreted factors in the rat uterus. RNA-sequencing (RNA-seq) data revealed that 10 genes are up-regulated in the delayed implantation uterus compared with the pseudopregnancy uterus. The RNA-seq results were further verified by real-time quantitative polymerase chain reaction. Sulf1 expression is significantly (P < 0.05) induced in the delayed implantation uterus, although Areg, Calca, Fxyd4 and Lamc3 show a definite but non-statistically significant increase in their expression levels. During early pregnancy, the levels of Areg, Calca, Fxyd4, Lamc3 and Sulf1 expression at 3.5 days post coitus (dpc) are significantly (P < 0.05) higher than those at 1.5 dpc. Treatment with embryo-conditioned media revealed that Lamc3 and Sulf1 are up-regulated compared with the other genes studied. Thus, embryo-derived factors regulate maternal gene expression, with Lamc3 and Sulf1 possibly being suitable markers for a response study of embryo-secreted factors to improve our understanding of embryo-maternal communication.