BMP4 in Human Endometrial Stromal Cells Can Affect Decidualization by Regulating FOXO1 Expression

Abstract Context Recurrent spontaneous abortion (RSA) is defined as the loss of 2 or more consecutive intrauterine pregnancies with the same sexual partner in the first trimester. Despite its significance, the etiology and underlying mechanisms of RSA remain elusive. Defective decidualization is proposed as one of the potential causes of RSA, with abnormal decidualization leading to disturbances in trophoblast invasion function. Objective To assess the role of bone morphogenetic protein 4 (BMP4) in decidualization and RSA. Methods Decidual samples were collected from both RSA patients and healthy controls to assess BMP4 expression. In vitro cell experiments utilized the hESC cell line to investigate the impact of BMP4 on decidualization and associated aging, as well as its role in the maternal-fetal interface communication. Subsequently, a spontaneous abortion mouse model was established to evaluate embryo resorption rates and BMP4 expression levels. Results Our study identified a significant downregulation of BMP4 expression in the decidua of RSA patients compared to the normal control group. In vitro, BMP4 knockdown resulted in inadequate decidualization and inhibited associated aging processes. Mechanistically, BMP4 was implicated in the regulation of FOXO1 expression, thereby influencing decidualization and aging. Furthermore, loss of BMP4 hindered trophoblast migration and invasion via FOXO1 modulation. Additionally, BMP4 downregulation was observed in RSA mice. Conclusion Our findings highlighted the downregulation of BMP4 in both RSA patients and mice. BMP4 in human endometrial stromal cells was shown to modulate decidualization by regulating FOXO1 expression. Loss of BMP4 may contribute to the pathogenesis of RSA, suggesting potential avenues for abortion prevention strategies.