Loss of miR-29a Impairs Decidualisation of Endometrial Stromal Cells by Enhancing TET3 Binding to the Col1A1 Promoter

MicroRNA-29a (miR-29a) plays an important role in the differentiation and proliferation of various uterine cells. However, whether miR-29a can regulate the proliferation and decidualisation of endometrial stromal cells (ESCs) remain to be elucidated. Inhibition of miR-29a led to decreased decidualisation and viability of ESCs in vitro. The expression of biomarkers PRL and IGFBP1, induced by decidualisation, reduced in the absence of miR-29a, while Tetmethylcytosine dioxygenase 3 (TET3) and its potential demethylation target, the collagen type I alpha 1 chain (COL1A1), were restored. The ChIP assay demonstrated that the binding capacity of TET3 to the Col1A1 promoter could be enhanced by the inhibition of miR-29a. Our study revealed that inhibition of miR-29a suppressed the decidualisation of ESCs by enhancing the recruitment of TET3 to the promoter region of Col1A1, thus revealing the critical role of the miR-29a/TET3/Col1A1 axis involved in the regulation of endometrial decidualisation and embryo implantation during early pregnancy.