Notch4 facilitates decidualization of human endometrial stromal cells through regulation of mesenchymal-epithelial transition

To investigate the mechanistic role of Notch4 signaling in the decidualization of human endometrial stromal cells (HESCs), with particular emphasis on mesenchymal-epithelial transition (MET) and its potential relevance to endometrial dysfunction. Primary HESCs were cultured and hormonally induced to undergo decidualization. Notch4 expression was silenced using lentiviral shRNA. The expression levels of decidualization markers (IGFBP1 and PRL), epithelial markers (E-cadherin, ZO-1, MUC-1), and mesenchymal markers (N-cadherin, Vimentin, ZEB1) were evaluated by RT-qPCR, Western blotting, and immunofluorescence. The expression of downstream Notch pathway components (DLL4, Jagged1/2, HES1/5, HEY1) was also assessed. Statistical analysis was performed using Student's t-test and one-way ANOVA. Notch4 expression was significantly upregulated during decidualization of HESCs. Notch4 knockdown markedly reduced the expression of decidualization markers IGFBP1 and PRL. In parallel, suppression of Notch4 attenuated MET, as evidenced by decreased epithelial markers (E-cadherin, ZO-1) and increased mesenchymal markers (N-cadherin, Vimentin). Furthermore, silencing Notch4 downregulated canonical Notch downstream targets, accompanied by impaired morphological changes associated with decidual transformation. Notch4 plays a regulatory role in decidualization of human endometrial stromal cells by modulating mesenchymal-epithelial transition. These findings provide a mechanistic evidence for future investigation into the role of Notch4 signaling in endometrial dysfunction associated with decidualization defects.