Loss of miR-29a impairs decidualization of endometrial stromal cells by TET3 mediated demethylation of Col1A1 promoter

The roles of chromatin regulatory factors in endometriosis

PURPOSE

Endometriosis is an estrogen-dependent inflammatory disease and one of the most common gynecological diseases in women of reproductive age. The aim of the review was to explore the relationship between the chromatin regulatory factors and endometriosis.

METHODS

By searching for literature on chromatin regulators and endometriosis in PuMed. Finally, 98 documents were selected.

RESULTS

Chromatin regulators (CRs) are essential epigenetic regulatory factors that can regulate chromatin structure changes and are usually divided into three categories: DNA methylation compounds, histone modification compounds, and chromatin remodeling complexes. Noncoding RNAs are also chromatin regulators and can form heterochromatin by binding to protein complexes. Chromatin regulators cause abnormal gene expression by regulating chromatin structure, thereby affecting the occurrence and development of endometriosis.

CONCLUSION

This review summarizes the participation of chromatin regulators in the mechanisms of endometriosis, and these changes in related chromatin regulators provide a comprehensive reference for diagnosis and treatment of endometriosis.

USP7 promotes decidualization of ESCs by STAT3/PR axis during early pregnancy

Decidualization is an essential process for embryo implantation during early pregnancy. Defective decidualization is a critical leading cause of early pregnancy loss (EPL). Ubiquitin-specific protease 7 (USP7) is a deubiquitinating enzyme that is involved in uterine function. This study aimed to explore the underlying mechanism by which USP7 regulates decidualization in EPL. We found that USP7 was downregulated in the decidual tissue of EPL patients. Upregulation of USP7 enhanced decidualization in endometrial stromal cells (ESCs), with increased decidualized biomarkers IGFBP1 and PRL and progesterone receptor A/B (PR-A/B) expression. Moreover, we found that signal transducer and activator of transcription 3 (STAT3) is a direct target of USP7 in ESCs. USP7 bound to STAT3 by deubiquitination and increased STAT3 levels in ESCs. Suppression of STAT3 impeded the USP7-promoted cell viability, decidualization, and PR-A/B expression of ESCs. USP7 promoted the decidualization of ESCs through the STAT3/PR signaling pathway during early pregnancy, which provides new insight into the pathological mechanism of EPL and may contribute to the clinical treatment of EPL.

The emerging role of TET enzymes in the immune microenvironment at the maternal-fetal interface during decidualization and early pregnancy

A dysregulated immune microenvironment at the maternal-fetal interface in early pregnancy may lead to early pregnancy loss, fetal growth restriction, and preeclampsia. However, major questions about how epigenetic modifications regulate the immune microenvironment during the decidualization process and embryo implantation remain unanswered. DNA methylation, the main epigenetic mechanism involved in the endometrial cycle, is crucial for specific transcriptional networks associated with endometrial stromal cell (ESC) proliferation, hormone response, decidualization, and embryo implantation. Ten-eleven translocation (TET) enzymes, responsible for catalyzing the conversion of 5-methylcytosine to 5-hydroxymethylcyosine, 5-formylytosine, and 5-carboxylcyosine to achieve the DNA demethylation process, appear to play a critical role in decidualization and embryo implantation. Here, we provide a comprehensive view of their structural similarities and the common mechanism of regulation in the microenvironment at the maternal-fetal interface during decidualization and early pregnancy. We also discuss their physiological role in the decidual immune microenvironment. Finally, we propose a key hypothesis regarding TET enzymes at the maternal-fetal interface between decidual immune cells and ESCs. Future work is needed to elucidate their functional role and examine therapeutic strategies targeting these enzymes in pregnancy-related disease preclinical models, which would be of great value for future implications in disease diagnosis or treatment.

Possible Involvement of miR-98 in the Regulation of PGRMC1 During Decidualization

Human endometrial stromal cells (ESCs) differentiate into decidual cells for embryo implantation during the mid-secretory phase of the menstrual cycle. Decidualization is characterized by enhanced production of insulin-like growth factor-binding protein 1 (IGFBP1) and prolactin (PRL) by ESCs and their morphological transformation into polygonal cells. Progesterone (P4) receptor membrane component 1 (PGRMC1) is a member of a P4-binding complex implicated in function in female reproduction. In this study, we explored the mechanisms that regulate PGRMC1 during decidualization of human ESCs. Immunohistochemical analysis of endometrial samples showed that PGRMC1 was expressed in endometrial glandular and luminal epithelial cells and stromal cells throughout the menstrual cycle; however, the protein level in stroma was reduced in the secretory phase. Incubation of ESCs with dibutyryl (db)-cAMP and P4 in vitro, which induces decidualization, decreased the PGRMC1 protein abundance. Further, treatment with a PGRMC1-targeting siRNA or PGRMC1 inhibitor (AG-205) promoted mRNA expression of the db-cAMP/P4- and db-cAMP-induced decidual markers IGFBP1 and PRL. Moreover, the microRNA miR-98, a potential repressor of PGRMC1, was upregulated during decidualization, and transfection of ESCs with a miR-98 mimic decreased the PGRMC1 protein level. These findings suggest that miR-98-mediated downregulation of endometrial PGRMC1 may promote decidualization for the establishment of pregnancy.