Gene expression analysis of membrane progesterone receptors in women with recurrent spontaneous abortion: a case control study

Endometrial Progesterone and Estrogen Receptors in Relation to Hormonal Levels in Women with Unexplained Recurrent Miscarriage

OBJECTIVE

 Recurrent miscarriage has been linked to hormonal disturbance due to dysregulation of its receptors rather than to the availability of the hormone. We aimed to investigate endometrial expression of progesterone and estrogen receptors in relation to serum and endometrial hormonal levels in unexplained recurrent miscarriage.

METHODS

 The present case control study included 20 cases with unexplained recurrent miscarriage and 20 parous women as controls. Ovulation was confirmed using an ovulation kit and 10 to 12 days after detecting the urinary luteinizing hormone surge, all women were subjected to a blood sample and to an endometrial biopsy. Progesterone and estrogen levels were measured in serum and in endometrial tissue and receptor concentrations were in the endometrial sample.

RESULTS

 Women with recurrent miscarriage showed significantly lower concentration of receptors in both the cytoplasm and the nucleus of endometrial tissue compared with controls. The nuclear/cytoplasm ratio of progesterone receptor was significantly higher in cases compared with controls, implicating that recurrent miscarriage is probably linked to nongenomic activity of the hormone; this was also significant for estrogen receptor. Serum progesterone and estrogen hormonal levels were comparable between groups while both hormones were significantly reduced in the endometrium of recurrent miscarriage cases. Receptors significantly correlated with endometrial hormonal level but not to serum level.

CONCLUSION

 Recurrent miscarriage might be linked to reduced endometrial progesterone and estrogen receptors and appears to be more related to nongenomic activity of progesterone. Endometrial receptors expression correlates to tissue hormonal level rather than to serum hormonal level.

Aberrant epigenetic regulation of estrogen and progesterone signaling at the level of endometrial/endometriotic tissue in the pathomechanism of endometriosis

Endometriosis is a term referring to a condition whereby the endometrial tissue is found outside the uterine cavity. This progressive and debilitating condition affects up to 15% of women of reproductive age. Due to the fact that endometriosis cells may express estrogen receptors (ERα, Erβ, GPER) and progesterone (P4) receptors (PR-A, PR-B), their growth, cyclic proliferation, and breakdown are similar to the processes occurring in the endometrium. The underlying etiology and pathogenesis of endometriosis are still not fully explained. The retrograde transport of viable menstrual endometrial cells with the retained ability to attach within the pelvic cavity, proliferate, differentiate and invade into the surrounding tissue explains the most widely accepted implantation theory. Endometrial stromal cells (EnSCs) with clonogenic potential constitute the most abundant population of cells within endometrium that resemble the properties of mesenchymal stem cells (MSCs). Accordingly, formation of the endometriotic foci in endometriosis may be due to a kind of EnSCs dysfunction. Increasing evidence indicates the underestimated role of epigenetic mechanisms in the pathogenesis of endometriosis. Hormone-mediated epigenetic modifications of the genome in EnSCs or even MSCs were attributed an important role in the etiopathogenesis of endometriosis. The roles of excess estrogen exposure and P4 resistance were also found to be crucial in the development of epigenetic homeostasis failure. Therefore, the aim of this review was to consolidate the current knowledge regarding the epigenetic background of EnSCs and MSCs and the changed properties due to estrogen/P4 imbalances in the context of the etiopathogenesis of endometriosis.

What Do We Know about Classical and Non-Classical Progesterone Receptors in the Human Female Reproductive Tract? A Review

The progesterone hormone regulates the human menstrual cycle, pregnancy, and parturition by its action via the different progesterone receptors and signaling pathways in the female reproductive tract. Progesterone actions can be exerted through classical and non-classical receptors, or even a combination of both. The former are nuclear receptors whose activation leads to transcriptional activity regulation and thus in turn leads to slower but long-lasting responses. The latter are composed of progesterone receptors membrane components (PGRMC) and membrane progestin receptors (mPRs). These receptors rapidly activate the appropriate intracellular signal transduction pathways, and they can subsequently initiate specific cell responses or even modulate genomic cell responses. This review covers our current knowledge on the mechanisms of action and the relevance of classical and non-classical progesterone receptors in female reproductive tissues ranging from the ovary and uterus to the cervix, and it exposes their crucial role in female infertility.

Estrogen- and Progesterone (P4)-Mediated Epigenetic Modifications of Endometrial Stromal Cells (EnSCs) and/or Mesenchymal Stem/Stromal Cells (MSCs) in the Etiopathogenesis of Endometriosis

Endometriosis is a common chronic inflammatory condition in which endometrial tissue appears outside the uterine cavity. Because ectopic endometriosis cells express both estrogen and progesterone (P4) receptors, they grow and undergo cyclic proliferation and breakdown similar to the endometrium. This debilitating gynecological disease affects up to 15% of reproductive aged women. Despite many years of research, the etiopathogenesis of endometrial lesions remains unclear. Retrograde transport of the viable menstrual endometrial cells with retained ability for attachment within the pelvic cavity, proliferation, differentiation and subsequent invasion into the surrounding tissue constitutes the rationale for widely accepted implantation theory. Accordingly, the most abundant cells in the endometrium are endometrial stromal cells (EnSCs). These cells constitute a particular population with clonogenic activity that resembles properties of mesenchymal stem/stromal cells (MSCs). Thus, a significant role of stem cell-based dysfunction in formation of the initial endometrial lesions is suspected. There is increasing evidence that the role of epigenetic mechanisms and processes in endometriosis have been underestimated. The importance of excess estrogen exposure and P4 resistance in epigenetic homeostasis failure in the endometrial/endometriotic tissue are crucial. Epigenetic alterations regarding transcription factors of estrogen and P4 signaling pathways in MSCs are robust in endometriotic tissue. Thus, perspectives for the future may include MSCs and EnSCs as the targets of epigenetic therapies in the prevention and treatment of endometriosis. Here, we reviewed the current known changes in the epigenetic background of EnSCs and MSCs due to estrogen/P4 imbalances in the context of etiopathogenesis of endometriosis. Graphical Abstract.

The correlation of estrogen receptor 1 and progesterone receptor genes polymorphisms with recurrent pregnancy loss in a cohort of Egyptian women

Recurrent pregnancy loss (RPL) represents one of the pregnancy complications affecting 1-3% of women. Sex hormones, progesterone and estrogen play a critical role in the maintenance of pregnancy; they are mediated by estrogen receptor 1 (ESR1) and progesterone receptor (PR) genes respectively. Polymorphisms of (ESR1) and (PR) genes are linked to RPL. We aimed to explore the association of single nucleotide polymorphisms (SNPs) of (ESR1) gene and (PR) gene with RPL in a cohort of Egyptian population (50 infertile Egyptian women who experienced RPL and 50 healthy women), using polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) of (ESR1) gene and DNA sequencing of exons 1 and 5 of (PR) gene. Genotyping of ESR1 gene SNP's: (rs2234693) and (rs9340799) revealed higher significance in cases compared to controls of p value (p = 0.006 and p = 0.001) respectively. However, the frequencies of the two variants in (PG) gene; S344T (rs3740753) (p = 0.0001) and H770H (rs1042839) (p = 0.001) were significantly higher in women compared to the healthy control women. New polymorphism P352Q was observed in 2% of cases (p = 0.0001). There was a significant association of SNP's of ESR1 and PR genes with recurrent pregnancy loss RPL. Further demographics studies should be carried on a larger number of women at risk of recurrent implantation to elucidate this SNP's association and its role in RPL women.

Selective ligands of membrane progesterone receptors as a key to studying their biological functions in vitro and in vivo

Progesterone modulates many processes in the body, acting through nuclear receptors (nPR) in various organs and tissues. However, a number of effects are mediated by membrane progesterone receptors (mPRs), which are members of the progestin and adipoQ (PAQR) receptor family. These receptors are found in most tissues and immune cells. They are expressed in various cancer cells and appear to play an important role in the development of tumors. The role of mPRs in the development of insulin resistance and metabolic syndrome has also attracted attention. Since progesterone efficiently binds to both nPRs and mPRs, investigation of the functions of the mPRs both at the level of the whole body and at the cell level requires ligands that selectively interact with mPRs, but not with nPRs, with an affinity comparable with that of the natural hormone. The development of such ligands faces difficulties primarily due to the lack of data on the three-dimensional structure of the ligand-binding site of mPR. This review is the first attempt to summarize available data on the structures of compounds interacting with mPRs and analyze them in terms of the differences in binding to membrane and nuclear receptors. Based on the identified main structural fragments of molecules, which affect the efficiency of binding to mPRs and are responsible for the selectivity of interactions, we propose directions of modification of the steroid scaffold to create new selective mPRs ligands.