摘要：

Objective MFG-E8 is a protein recently discovered by us in the human endometrium, with predominant localization in the epithelium during the window o f implantation. Our recent findings have shown that MFG-E8 promotes endometrial epithelial cell migration. Studies on non-uterine cancer cells have implicated that MFG-E8 promotes cell invasion and metastasis, in which epithelial cells acquire molecular features leading to EMT. It is not known whether MFG-E8 regulates EMT in the endometrium. TGF-β is a cytokine synthesized by trophoblast and a known EMT inducer in many tissues including endometrium. Thus, we hypothesized that embryonic TGF-β and endometrial MFG-E8 may co-participate in the modulation of EMT, contributing to implantation. Design An in vitro model was used to investigate whether endometrial MFG-E8 affects TGF-β induced EMT. Materials and Methods HEC-1A cells (which express MFG-E8 abundantly) were used as surrogate for human endometrial epithelial cells and were transfected with shRNA plasmids to inhibit MFG-E8 expression. The efficiency of MFG-E8 knockdown was determined by real-time qPCR and western blot. After two days treatment with recombinant TGF-β (20 ng/ml), induction of EMT was assessed by phenotypic changes (using inverted microscopy) and by expression changes of E- and N-cadherin (using immunofluorescence and western blot). Results Exposure to TGF-β induced EMT in HEC-1A cells. Morphological changes consistent with EMT included observation of spindle-shaped cells. Biochemical changes included down regulation of E-cadherin and up regulat ion of N-cadherin protein levels by immunofluorescence and western blot (both p < 0.05). Moreover, the TGF-β- induced EMT was significantly inhibited by silencing MFG-E8 (p < 0.05 in western results). Conclusion In this study, we provide novel evidence that MFG-E8, a potent promoter of epithelial migration, mediates the TGF-β-induced EMT. This could be a mechanism involved in epithelium remodeling during trophoblast implantation.

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