Abstract: Objective: To investigate the effects of YY1-TGF-β1-MMPs signal axis on trophoblast cell activity, invasion and migration. Methods: HTR8/SVneo trophoblast cell line was used as the research object to construct the cell model of the YY1 knockdown (siYY1) group and the normal expression (NC) group. The experimental groups were divided into NC group, siYY1 group and siYY1+SD-208 (TGF-β inhibitor, 1 μmol/L, 48 h) group. RT-PCR and Western blotting were used to detect the expression of the signaling pathway related molecules; CCK-8 was used to detect cell viability; scratch assay and Trans-well assay were used to detect cell migration and invasion. Results: The cell viability, migration and invasion ability of siYY1 group were significantly attenuated, and the expression levels of MMP-2 and MMP-9 were significantly decreased, while TIMP1 and TIMP2 were significantly increased. In addition, the expression levels of TGF-β1, Smad2 and Smad3 were significantly increased, while the expression of inhibitory Smad7 was decreased. Subsequent treatment with TGF-β inhibitors significantly improved the activity, invasion and migration of YY1 knockdown cells. Conclusions: The signal axis of YY1-TGF-β1 can regulate the activity, invasion and migration of trophoblast cells, which may be involved in embryo implantation and placental development, resulting in miscarriage.

Key words: Yin Yang-1, Transforming growth factor beta1, Trophoblast, Abortion