Membrane Progesterone Receptor Beta Regulates the Decidualization of Endometrial Stromal Cells in Women with Endometriosis.

Endometriosis is a disorder characterized by the presence of endometrial tissue outside the uterus, leading to dyspareunia, chronic pelvic pain, dysuria, and infertility. The latter has been related to implantation failure associated with alterations in decidualization, a process regulated by sex hormones such as progesterone. Membrane progesterone receptor β (mPRβ) exhibits a lower expression in endometriotic tissues than in normal endometrial ones. However, the role of mPRβ in decidualization is unknown. This work aimed to investigate whether mPRβ plays a role in the decidualization of endometrial stromal cells (ESCs) derived from women with and without endometriosis. The mPR agonist OrgOD-2 induced the gene expression of key decidualization markers (insulin-like growth factor binding protein 1, prolactin, transcription factor heart and neural crest derivatives-expressed transcript 2, and fork-head transcription factor) in healthy ESCs, eutopic (uterine cavity), and ectopic (outside of the uterine cavity) ESCs from women with endometriosis. Notably, the expression of the decidualization markers was lower in endometriotic cells than in healthy endometrial ones. An siRNA mediated knockdown of mPRβ reduced the expression of decidualization-associated genes in ESCs treated with a decidualization stimuli, regardless of whether cells were derived from healthy women or those with endometriosis. Our data suggest that progesterone, through mPRβ activation, regulates the decidualization process in endometrial stromal cells from women with and without endometriosis.