MicroRNA-regulated pathways associated with endometriosis

Role of Salivary MicroRNA as a Marker of Progesterone Resistance in Endometriosis: Preliminary Results from a Single-Institution Experience

This feasibility study explores the potential of salivary microRNAs (miRNAs) as non-invasive biomarkers for diagnosing endometriosis and assessing treatment response. Almost one-third of patients with endometriosis do not respond to the standard progestin treatment due to various mechanisms of progesterone resistance. MiRNAs, recognized for their stability in body fluids and role in gene regulation, may offer new diagnostic and prognostic opportunities as they are involved in the pathogenic pathways of endometriosis and progesterone resistance. We sequenced salivary miRNAs in three cohorts of patients: control women without endometriosis and patients with endometriosis who responded and did not respond to standard progestin treatment. This aims to identify the differential miRNA expression profiles associated with therapeutic response to dienogest. The preliminary results demonstrate the feasibility of miRNA sequencing from saliva and reveal distinct miRNA profiles between responders, non-responders, and controls. Key miRNAs, including mir-3168, the mir-200a family, and mir-93-5p, emerged as potential biomarkers, showing significant differential expression linked to both endometriosis presence and treatment response. Further validation of these findings in larger cohorts could pave the way for miRNA-based diagnostic and prognostic tools, potentially reducing diagnostic delays and personalizing treatment approaches for endometriosis patients, also with new target therapies.

Biomarkers of endometriosis

Endometriosis represents a diverse disease characterized by three distinct phenotypes: superficial peritoneal lesions, ovarian endometriomas, and deep infiltrating endometriosis. The most widely accepted pathophysiological hypothesis for endometriosis is rooted in retrograde menstruation, a phenomenon observed in most patients. Endometriosis is closely linked to infertility, but having endometriosis does not necessarily imply infertility. The disease can impact fertility through various mechanisms affecting the pelvic cavity, ovaries, and the uterus itself. MicroRNAs (miRNAs) indeed represent a fascinating and essential component of the regulatory machinery within cells. Discovered in the early 1990s, miRNAs have since been identified as critical players in gene expression control. Unfortunately, ovarian endometrioma is a common gynecologic disorder for which specific serum markers are currently lacking. Some have examined urocortin for its ability to differentiate endometriomas from other benign ovarian cysts. Another potential marker, Cancer Antigen 125 (CA-125) is a well-established indicator for epithelial cell ovarian cancer and its levels can be elevated in conditions such as endometriosis. CA-125 is derived from coelomic epithelia, including the endometrium, fallopian tube, ovary, and peritoneum. In this review we examine the pathophysiologic basis for endometriosis and highlight potential markers to more fully characterize the underlying biochemical processes linked to this multifaceted disease state.

Identification and analysis of oxidative stress-related genes in endometriosis

Background

Early diagnosis and treatment of endometriosis (EM) remain challenging because of the lack of knowledge about EM development. While oxidative stress (OS) has been associated with EM, the link is unclear. We explored OS-related genes (OSRGs) and their role in EM pathogenesis.

Material and methods

We combined two ectopic endometrium (EC) and eutopic endometrium (EU) datasets (GSE11691 and GSE25628) into a dataset for analysis. Bioinformatic analyses were used to identify differentially expressed genes (DEGs), OS-related genes (OSRGs), enriched pathways, competitive endogenous RNA network, and immune cell infiltration. Finally, real time-quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB) were used to validate the expression of key OSRGs in clinical patient samples.

Results

Bioinformatic analysis identified 459 DEGs between EC and EU samples, including 67 OSRGs. A ceRNA network was established, encompassing 28 DE-OSRGs, 32 miRNAs, and 53 lncRNAs. Four key OSRGs (CYP17A1, NR3C1, ENO2, and NGF) were selected from protein-protein interaction network analysis. The RT-qPCR and WB analysis showed that these genes' abnormal changes in RNA and protein levels were consistent with data in public databases. Weighted gene co-expression network analysis identified three immune-related OSRGs (CYP17A1, NR3C1, and NGF) and 20 lncRNAs that may regulate NR3C1 through 10 miRNAs.

Conclusion

The key OSRGs may function via multilayered networks in EM. We provide insights into EM and underscore the potential significance of OSRGs and the immune environment for diagnostic and prognosis evaluation.

Spatial transcriptomic analysis identifies epithelium-macrophage crosstalk in endometriotic lesions

The mechanisms underlying the pathophysiology of endometriosis, characterized by the presence of endometrium-like tissue outside the uterus, remain poorly understood. This study aimed to identify cell type-specific gene expression changes in superficial peritoneal endometriotic lesions and elucidate the crosstalk among the stroma, epithelium, and macrophages compared to patient-matched eutopic endometrium. Surprisingly, comparison between lesions and eutopic endometrium revealed transcriptional similarities, indicating minimal alterations in the sub-epithelial stroma and epithelium of lesions. Spatial transcriptomics highlighted increased signaling between the lesion epithelium and macrophages, emphasizing the role of the epithelium in driving lesion inflammation. We propose that the superficial endometriotic lesion epithelium orchestrates inflammatory signaling and promotes a pro-repair phenotype in macrophages, providing a new role for complement 3 in lesion pathobiology. This study underscores the significance of considering spatial context and cellular interactions in uncovering mechanisms governing disease in endometriotic lesions.

Expression of E-CADHERIN and miR-200b in Different Forms of Endometriosis

Background/Objectives: Epithelial-Mesenchymal Transition (EMT) is the process by which epithelial cells acquire mesenchymal properties, which helps endometriotic cells migrate and invade. This study looks at the expression of E-CADHERIN, a critical epithelial marker, and miR-200b, an EMT regulator, in several types of endometriosis, including endometriomas and deep infiltrating endometriotic (DIE) nodules. Methods: We examined 19 individuals with endometriosis (9 with just endometriotic cysts and 10 with both DIE and endometriotic cysts) and 8 controls with benign gynecological abnormalities. Tissue samples were taken during laparoscopic surgery, and E-CADHERIN and miR-200b expression were measured using Real-Time PCR, with G6PD and U6 as controls. Results:E-CADHERIN expression was maintained in the eutopic endometrium of both ovarian and DIE types, but it was considerably reduced in endometriotic cysts, indicating heightened mesenchymal features. miR-200b was downregulated in the eutopic endometrium of ovarian endometriosis but upregulated in DIE. Endometriotic cysts in both groups had greater miR-200b expression than their corresponding eutopic endometrium. E-CADHERIN and miR-200b expression in DIE lesions was similar to that found in matched eutopic endometrium. Conclusions: The regulation of E-CADHERIN and miR-200b varies across ovarian and DIE lesions. The miR-200b-ZEB1 feedback loop is increased in DIE eutopic endometrium but downregulated in ovarian endometriosis. E-CADHERIN downregulation in endometriotic cysts indicates heightened mesenchymal dynamics, whereas DIE nodules have gene expression patterns similar to eutopic endometrium. These findings emphasize the distinct regulatory processes that govern endometriotic lesions.

Serum-derived small extracellular vesicles as biomarkers for predicting pregnancy and delivery on assisted reproductive technology in patients with endometriosis

Introduction

Endometriosis can cause of infertility, and evaluation methods for predicting clinical pregnancy outcomes are desired. Extracellular vesicles (EVs) exist in blood and it contains small non-coding RNAs (ncRNAs) that may reflect disease severity. In this study, we investigated small ncRNAs in serum EVs to identify specific biomarkers for predicting clinical pregnancy.

Methods

Serum samples were collected from 48 patients who underwent assisted reproductive technology (ART). EVs were successfully isolated from serum samples and characterized using nanoparticle tracking assays, electron microscopy, and western blotting of EV's markers. We performed small RNA sequencing and analyzed microRNA (miRNA) profiles in the infertility patients with and without endometriosis to detect pregnancy-predicting biomarkers.

Results

Candidate miRNAs in serum EVs were selected by comparing patients without endometriosis who became pregnant (n = 13) with those who did not (n = 21). A total of 241 miRNAs were detected; however, no trends separated the two groups. Next, EVs from patients with endometriosis were analyzed and divided into pregnant (n = 4) and non-pregnant (n = 10) cases. Among the 224 candidate miRNAs, miRNA profiles of pregnant women with endometriosis were separated from those of non-pregnant women by receiver-operating characteristics (ROC) curve analysis (area under the curve [AUC] > 0.8). In patients with endometriosis, serum EVs may be useful for predicting possible pregnancy before infertility treatment. Finally, we used small RNA sequencing of the tissue to demonstrate that pregnancy-predicting miRNAs in serum EVs were produced from endometriosis lesions. Although no predictors were found from miRNAs in serum EVs without endometriosis, miRNAs in serum EVs of patients with endometriosis could provide novel noninvasive biomarkers to predict pregnancy and have potential clinical applicability in ART.

Discussion

Further studies are required to examine the functional importance of these miRNAs to elucidate the pathological mechanisms of endometriosis and pregnancy.

Endometrial Receptivity-Lessons from "Omics"

The window of implantation (WOI) is a critical phase of the menstrual cycle during which the endometrial lining becomes receptive and facilitates embryo implantation. Drawing on findings from various branches of "omics", including genomics, epigenomics, transcriptomics, proteomics, lipidomics, metabolomics, and microbiomics, this narrative review aims to (1) discuss mechanistic insights on endometrial receptivity and its implication in infertility; (2) highlight advances in investigations for endometrial receptivity; and (3) discuss novel diagnostic and therapeutic strategies that may improve reproductive outcomes.

Combined targeting of TCF7L1/2, PTEN, CDK6, and BCCIP by microRNA miR-29c-3p is associated with reduced invasion and proliferation of endometriotic cells

Purpose

Endometriosis is a chronic gynecological disorder associated with pain symptoms and infertility. The expression of microRNA miR-29c-3p is dysregulated in endometriosis. We aimed to identify novel molecular targets of miR-29c-3p functionally linked to proliferation and invasive growth in endometriosis.

Methods

The epithelial endometriotic cell line 12Z and primary endometriotic stromal cells (PESC) were transfected with control miRNA or pre-miR-29c-3p, and subjected to cell cycle analysis, cell viability, wound healing, and Matrigel invasion assays. Expression of bioinformatically predicted miR-29c-3p targets was analyzed by qPCR and western blot. Target gene expression in endometriotic lesions and healthy endometrium was studied in the EndometDB endometriosis database.

Results

miR-29c-3p decreased 12Z and PESC cell viability and the proportion of PESC in the S-phase. 12Z cell invasion, but not migration, was decreased after miR-29c-3p upregulation. miR-29c-3p decreased the mRNA expression of CDK6, BCCIP, TCF7L1, TCF7L2, PTEN, COL4A1, E-Cadherin, and N-Cadherin. A decrease of CDK6 and PTEN and an increase of p21 were confirmed at the protein level. EndometDB database analysis demonstrated dysregulated expression of the selected targets in both deep endometriosis and ovarian endometriosis.

Conclusions

miR-29c-3p effectively curbs endometriotic cell proliferation and invasion by combined inhibition of cell cycle regulators and transcription factors, unveiling a promising therapeutic strategy.

MicroRNAs as Biomarkers and Therapeutic Targets in Female Infertility

The study of microRNAs (miRNAs) has emerged in recent decades as a key approach to understanding the pathophysiology of many diseases, exploring their potential role as biomarkers, and testing their use as future treatments. Not only have neurological, cardiovascular diseases, or cancer benefited from this research but also infertility. Female infertility, as a disease, involves alterations at multiple levels, such as ovarian and uterine alterations. This review compiles the latest studies published in humans that link female disorders that affect fertility with altered miRNA profiles. Studies on ovarian alterations, including diminished ovarian reserve (DOR), poor ovarian response to stimulation (POR), premature ovarian insufficiency (POI), and polycystic ovary syndrome (PCOS), are summarized and classified based on the expression and type of sample analyzed. Regarding uterine disorders, this review highlights upregulated and downregulated miRNAs primarily identified as biomarkers for endometriosis, adenomyosis, decreased endometrial receptivity, and implantation failure. However, despite the large number of studies in this field, the same limitations that reduce reproducibility are often observed. Therefore, at the end of this review, the main limitations of this type of study are described, as well as specific precautions or safety measures that should be considered when handling miRNAs.

Decreased expression of miR-200a and miR-223-3p in endometriosis during the secretory phase of menstrual cycle: Insights from a case-control study on molecular biomarkers and disease-related infertility

Background

Endometriosis (EM) is a condition that causes infertility with decreasing uterine receptivity. It is reported that it affects about 20-25% of all infertile women. Some genetic markers play a crucial role in pathogenesis and infertility.

Objective

This study investigates the role of miR-200a and miR-223-3p in embryo implantation and their association with EM-related infertility.

Materials and Methods

In this case-control study, 36 women who referred to the Center for Research on Reproductive Health and Infertility of Babol University of Medical Sciences and Fatemeh Al-Zahra Infertility Specialized Treatment Center in Babol, Iran between June 2022 and July 2023 were evaluated. Participants were divided into 2 EM and control groups (n = 18/each). Endometrial samples were collected from participants between 17  th and 24  th days of their menstrual cycle. Histopathological examination (hematoxylin and eosin and periodic acid schiff) was performed to confirm the secretory stage, and miR-200a and miR-223-3p expressions were analyzed by quantitative reverse transcriptase-polymerase chain reaction.

Results

Histological analysis confirmed that both groups were in the secretory stage. Additionally, miRNA expression results showed a significant decrease in the miR-200a and miR-223-3p expression levels in EM group compared to control group. The expression level of miR-223-3p and miR-200a in the eutopic endometrial tissue of women with EM was notably lower than those in the control group.

Conclusion

Our results suggest that miR-200a and miR-223-3p are involved in the EM pathogenesis, while other genes and signaling pathways are probably involved in the implantation failure.

miR-193b-5p and miR-374b-5p Are Aberrantly Expressed in Endometriosis and Suppress Endometrial Cell Migration In Vitro

(1) Background: Endometriosis is a highly prevalent gynecological disease affecting 10% of women of reproductive age worldwide. miRNAs may play a role in endometriosis, though their exact function remains unclear. This study aimed to identify differentially expressed miRNAs in endometriosis and study their functions in the disease. (2) Methods: Endometrial tissue was collected from women with endometriosis (n = 15) and non-endometriosis controls (n = 17). Dysregulated miRNAs were identified through small RNA-sequencing, and their biological significance was explored by target gene prediction and pathway analysis. Selected miRNAs were examined in paired ectopic endometriomas and eutopic endometrium (n = 10) using qRT-PCR. Their roles in cell migration and proliferation were further examined in vitro using functional assays. To identify potential target genes, we performed mRNA sequencing on transfected cells and the endometrioma cohort. (3) Results: We identified 14 dysregulated miRNAs in the eutopic endometrium of women with endometriosis compared to endometrial tissue from women without endometriosis. Pathway analysis indicated enrichment in cell migration and proliferation-associated pathways. Further ex vivo studies of miR-193b-5p and miR-374b-5p showed that both miRNAs were upregulated in endometrioma. Overexpression of these two miRNAs in vitro inhibited cell migration, and mRNA sequencing revealed several migration-related genes that are targeted by these miRNAs. (4) Conclusions: Our study identified two key endometrial miRNAs that may be involved in the pathogenesis of endometriosis by regulating cell migration.

Expression of Reversion-Inducing Cysteine-Rich Protein with Kazal Motifs (RECK) Gene and Its Regulation by miR200b in Ovarian Endometriosis

Endometriosis is a common chronic disorder characterized by the growth of endometrium-like tissue outside the uterine cavity. The disease is associated with chronic inflammation and pelvic pain and may have an impact on the patient's fertility. The causative factors and pathophysiology of the disease are still poorly recognized. The dysregulation of the immune system, aberrant tissue remodeling, and angiogenesis contribute to the disease progression. In endometriosis patients, the proteins regulating the breakdown and reorganization of the connective tissue, e.g., collagenases, and other proteases, as well as their inhibitors, show an incorrect pattern of expression. Here, we report that the expression of reversion-inducing cysteine-rich protein with Kazal motifs (RECK), one of the inhibitors of connective tissue proteases, is elevated in endometrioma cysts as compared to normal endometrium from unaffected women. We also demonstrate a reduced level of miR200b in endometriotic tissue that correlates with RECK mRNA levels. Furthermore, we employ the 12Z cell line, derived from a peritoneal endometriotic lesion, and the Ishikawa cell line, originating from endometrial adenocarcinoma to identify RECK as a direct target of miR200b. The described effect of miR200b on RECK, together with the aberrant expression of both genes in endometrioma, may help to understand the role played by the tissue remodeling system in the pathogenesis of endometriosis.

Decoding the Promise and Challenges of miRNA-Based Cancer Therapies: An Essential Update on miR-21, miR-34, and miR-155

MicroRNAs (miRNAs)-based therapies hold great promise for cancer treatment, challenges such as expression variability, off-target effects, and limited clinical effectiveness have led to the withdrawal of many clinical trials. This review investigates the setbacks in miRNA-based therapies by examining miR-21, miR-34, and miR-155, highlighting their functional complexity, off-target effects, and the challenges in delivering these therapies effectively. Moreover, It highlights recent advances in delivery methods, combination therapies, and personalized treatment approaches to overcome these challenges. This review highlights the intricate molecular networks involving miRNAs, particularly their interactions with other non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), emphasizing the pivotal role of miRNAs in cancer biology and therapeutic strategies. By addressing these hurdles, this review aims to steer future research toward harnessing the potential of miRNA therapies to target cancer pathways effectively, enhance anti-tumor responses, and ultimately improve patient outcomes in precision cancer therapy.

Circulating Serum Micro-RNA as Non-Invasive Diagnostic Biomarkers of Endometriosis

BACKGROUND/OBJECTIVES

Endometriosis (END) is a painful gynecological condition. Clinical examination, imaging, and laparoscopy can provide a definitive diagnosis of END. Nonetheless, non-invasive biomarkers could help enhance and streamline the diagnostic process. Micro-RNAs (miRNAs), a family of small non-coding RNAs, could serve as useful non-invasive biomarkers for END. The aim of this study was to perform serum miRNA profiling in a retrospective cohort of women to identify miRNAs that are differentially expressed in END compared to control patients.

METHODS

RNA was isolated from serum samples of 67 END patients and 60 control women. The expression profile of a 754-miRNA panel was studied with RT-qPCR performed on a QuantStudio 12K Flex with the TaqMan OpenArray miRNA panel. A Censored Regression Model was used for miRNA differential expression analysis. Several gene-enrichment algorithms were employed to identify pathways related to the target genes of differentially expressed miRNAs.

RESULTS

One hundred and thirty miRNAs were detected in at least 75% of samples from either the END or the control group. Sixteen miRNAs were significantly modulated between the END and control groups. Enrichment analysis identified targets significantly overrepresented in numerous pathways involved in biological processes related to END, including inflammation, angiogenesis, cellular invasion, cell-cycle/cell proliferation, and estrogen and progesterone hormonal signaling.

CONCLUSIONS

Our study indicates that differentially expressed miRNAs between END patients and controls can be identified through liquid biopsy. Our findings also suggest a potential role for serum miRNAs in the pathophysiology of END, warranting further investigations for their use as non-invasive biomarkers.

Exploring the Role of MicroRNAs in Progesterone and Estrogen Receptor Expression in Endometriosis

Background/Objectives: Patients with endometriosis still respond poorly to progestins due to progesterone resistance associated with microRNAs (miRNAs). The aim of this study was to investigate the expression of selected miRNAs, estrogen receptor (ER)α, ERβ, progesterone receptor (PR)-A and PR-B and to determine the target genes of upregulated miRNAs in endometriosis. Methods: In this study, 18 controls, 18 eutopic and 18 ectopic samples were analysed. Profiling and validation of miRNAs associated with functions of endometriosis were performed using next-generation sequencing (NGS) and qRT-PCR. At the same time, the expression of ERα, ERβ, PR-A and PR-B was also determined using qRT-PCR. Target prediction was also performed for miR-199a-3p, miR-1-3p and miR-125b-5p using StarBase. Results: In this study, NGS identified seven significantly differentially expressed miRNAs, of which six miRNAs related to the role of endometriosis were selected for validation by qRT-PCR. The expression of miR-199a-3p, miR-1-3p, miR-146a-5p and miR-125b-5p was upregulated in the ectopic group compared to the eutopic group. Meanwhile, ERα and ERβ were significantly differentially expressed in endometriosis compared to the control group. However, the expressions of PR-A and PR-B showed no significant differences between the groups. The predicted target genes for miR-199a-3p, miR-1-3p and miR-125b-5p are SCD, TAOK1, DDIT4, LASP1, CDK6, TAGLN2, G6PD and ELOVL6. Conclusions: Our findings demonstrated that the expressions of ERα and ERβ might be regulated by miRNAs contributing to progesterone resistance, whereas the binding of miRNAs to target genes could also contribute to the pathogenesis of endometriosis. Therefore, miRNAs could be used as potential biomarkers and for targeted therapy in patients with endometriosis.

Diagnostic Value and Molecular Function of MicroRNAs in Endometrial Diseases: A Systematic Review

The human endometrium experiences significant cyclic morphological and biochemical changes throughout the menstrual cycle to prepare for embryo implantation. These processes are meticulously regulated by ovarian steroids and various locally expressed genes, encompassing inflammatory reactions, apoptosis, cell proliferation, angiogenesis, differentiation (tissue formation), and tissue remodeling. MicroRNAs (miRNAs) have been recognized as crucial regulators of gene expression, with their altered expression being linked to the onset and progression of various disorders, including cancer. This review examines the expression of miRNAs in the endometrium and their potential regulatory roles under pathological conditions such as endometriosis, recurrent implantation failure and endometrial cancer. Given miRNAs' critical role in maintaining gene expression stability, understanding the regulatory mechanisms of endometrial miRNAs and identifying their specific target genes could pave the way for developing preventive and therapeutic strategies targeting specific genes associated with these reproductive disorders.

Endometriosis: Molecular Pathophysiology and Recent Treatment Strategies-Comprehensive Literature Review

Endometriosis is an enigmatic disease, with no specific cause or trigger yet discovered. Major factors that may contribute to endometriosis in the pelvic region include environmental, epigenetic, and inflammatory factors. Most experts believe that the primary mechanism behind the formation of endometrial lesions is associated with Sampson's theory of "retrograde menstruation". This theory suggests that endometrial cells flow backward into the peritoneal cavity, leading to the development of endometrial lesions. Since this specific mechanism is also observed in healthy women, additional factors may be associated with the formation of endometrial lesions. Current treatment options primarily consist of medical or surgical therapies. To date, none of the available medical therapies have proven effective in curing the disorder, and symptoms tend to recur once medications are discontinued. Therefore, there is a need to explore and develop novel biomedical targets aimed at the cellular and molecular mechanisms responsible for endometriosis growth. This article discusses a recent molecular pathophysiology associated with the formation and progression of endometriosis. Furthermore, the article summarizes the most current medications and surgical strategies currently under investigation for the treatment of endometriosis.

Growing Role of 3D In Vitro Cell Cultures in the Study of Cellular and Molecular Mechanisms: Short Focus on Breast Cancer, Endometriosis, Liver and Infectious Diseases

Over the past decade, the development of three-dimensional (3D) models has increased exponentially, facilitating the unravelling of fundamental and essential cellular mechanisms by which cells communicate with each other, assemble into tissues and organs and respond to biochemical and biophysical stimuli under both physiological and pathological conditions. This section presents a concise overview of the most recent updates on the significant contribution of different types of 3D cell cultures including spheroids, organoids and organ-on-chip and bio-printed tissues in advancing our understanding of cellular and molecular mechanisms. The case studies presented include the 3D cultures of breast cancer (BC), endometriosis, the liver microenvironment and infections. In BC, the establishment of 3D culture models has permitted the visualization of the role of cancer-associated fibroblasts in the delivery of exosomes, as well as the significance of the physical properties of the extracellular matrix in promoting cell proliferation and invasion. This approach has also become a valuable tool in gaining insight into general and specific mechanisms of drug resistance. Given the considerable heterogeneity of endometriosis, 3D models offer a more accurate representation of the in vivo microenvironment, thereby facilitating the identification and translation of novel targeted therapeutic strategies. The advantages provided by 3D models of the hepatic environment, in conjunction with the high throughput characterizing various platforms, have enabled the elucidation of complex molecular mechanisms underlying various threatening hepatic diseases. A limited number of 3D models for gut and skin infections have been developed. However, a more profound comprehension of the spatial and temporal interactions between microbes, the host and their environment may facilitate the advancement of in vitro, ex vivo and in vivo disease models. Additionally, it may pave the way for the development of novel therapeutic approaches in diverse research fields. The interested reader will also find concluding remarks on the challenges and prospects of using 3D cell cultures for discovering cellular and molecular mechanisms in the research areas covered in this review.

Spatial Transcriptomic Analysis Identifies Epithelium-Macrophage Crosstalk in Endometriotic Lesions

The mechanisms underlying the pathophysiology of endometriosis, characterized by the presence of endometrium-like tissue outside the uterus, remain poorly understood. This study aimed to identify cell type-specific gene expression changes in superficial peritoneal endometriotic lesions and elucidate the crosstalk among the stroma, epithelium, and macrophages compared to patient-matched eutopic endometrium. Surprisingly, comparison between lesions and eutopic endometrium revealed transcriptional similarities, indicating minimal alterations in the sub-epithelial stroma and epithelium of lesions. Spatial transcriptomics highlighted increased signaling between the lesion epithelium and macrophages, emphasizing the role of the epithelium in driving lesion inflammation. We propose that the superficial endometriotic lesion epithelium orchestrates inflammatory signaling and promotes a pro-repair phenotype in macrophages, providing a new role for Complement 3 in lesion pathobiology. This study underscores the significance of considering spatial context and cellular interactions in uncovering mechanisms governing disease in endometriotic lesions.

Endometriosis-Associated Ovarian Cancer: From Molecular Pathologies to Clinical Relevance

Endometriosis is a chronic condition affecting reproductive-aged women, characterized by the growth of ectopic endometrial tissue. Despite being benign, endometriosis is associated with an increased risk of certain cancers, including endometriosis-associated ovarian cancer (EAOC). Ovarian cancer is rare, but more common in women with endometriosis, particularly endometrioid and clear-cell carcinomas. Factors such as hormonal imbalance, reproductive history, environmental exposures, and genetic predisposition contribute to the malignant transformation of endometriosis. Thus, understanding potential risk factors causing malignancy is crucial. Over the past few decades, various genetic mutations, microRNAs, as well as tumor microenvironmental factors have been identified, impacting pathways like PI3K/AKT/mTOR, DNA repair mechanisms, oxidative stress, and inflammation. Thus, this review aims to summarize molecular studies involved in EAOC pathogenesis as potential therapeutic targets. However, further research is needed to better understand the molecular and environmental factors driving EAOC development, to target the susceptibility of endometriotic lesions to malignant progression, and to identify effective therapeutic strategies.

Exploring the Effects of Endocrine-Disrupting Chemicals and miRNA Expression in the Pathogenesis of Endometriosis by Unveiling the Pathways: a Systematic Review

Endometriosis, characterized by endometrial-like mucosal tissue outside the uterine cavity, is a reproductive disorder afflicting about 10% of women within the reproductive age. The pathogenesis of endometriosis has been attributed to factors like genetics, environmental particles, and hormones. A comprehensive review of studies from July 2010 to July 2023 across multiple databases was done to aid in a better understanding of the same. The investigation focused on studies delineating the correlation between endocrine disruptors, microRNAs, and endometriosis. To optimize the search scope, keywords and subject headings were used as search terms. Then, two authors rigorously assessed studies using criteria, selecting 27 studies from various databases. Notably, dioxins, organochlorine pesticides, and polychlorinated biphenyls exhibited a solid connection for endometriosis, while bisphenol A and phthalates yielded conflicting results. The heightened presence of bisphenol A, polychlorinated biphenyls, and phthalates was linked to altered gene expression, including genes like AKR1B10, AKR1C3, and FAM49B. MicroRNAs like miRNA-31, miRNA-144, and miRNA-145 emerged as vital factors in the onset of endometriosis and progression. Furthermore, elevated expression of miR-1304-3p, miR-544, and miR-3684 and reduced expression of miR-3935 and miR-4427 exert substantial influence on signaling pathways like NF-κB, MAPK, and Wnt/β-catenin. Currently, literature shows an independent link between endocrine disruptor exposure and endometriosis and between microRNA dysregulation and endometriosis. However, research lacks the combination of all three factors. The review delves into the effects of endocrine disruptors and microRNAs on the pathogenesis of endometriosis to improve our understanding of the disorder and in finding therapies.

MiRNAs related in signaling pathways of women's reproductive diseases: an overview

BACKGROUND

One of the main health issues that can affect women's health is reproductive diseases, such as polycystic ovary syndrome (PCOS), endometriosis (EMs), uterine leiomyomas (ULs), and ovarian cancer (OC). Although these diseases are very common, we do not have a complete understanding of their underlying cellular and molecular mechanisms. It is important to mention that the majority of patients are diagnosed with these diseases at later stages because of the absence of early diagnostic techniques and dependable molecular indicators. Hence, it is crucial to discover novel and non-invasive biomarkers that have prognostic, diagnostic and therapeutic capabilities. MiRNAs, also known as microRNAs, are small non-coding RNAs that play a crucial role in regulating gene expression at the post-transcriptional level. They are short in length, typically consisting of around 22 nucleotides, and are highly conserved across species. Numerous studies have shown that miRNAs are expressed differently in various diseases and can act as either oncogenes or tumor suppressors.

METHODS

The author conducted a comprehensive review of all the pertinent papers available in web of science, PubMed, Google Scholar, and Scopus databases.

RESULTS

We achieved three goals: providing readers with better information, enhancing search results, and making peer review easier.

CONCLUSIONS

This review focuses on the investigation of miRNAs and their involvement in various reproductive disorders in women, including their molecular targets. Additionally, it explores the role of miRNAs in the development and progression of these disorders.

Identification of miR-30c-5p microRNA in Serum as a Candidate Biomarker to Diagnose Endometriosis

The diagnosis of endometriosis by laparoscopy is delayed until advanced stages. In recent years, microRNAs have emerged as novel biomarkers for different diseases. These molecules are small non-coding RNA sequences involved in the regulation of gene expression and can be detected in peripheral blood. Our aim was to identify candidate serum microRNAs associated with endometriosis and their role as minimally invasive biomarkers. Serum samples were obtained from 159 women, of whom 77 were diagnosed with endometriosis by laparoscopy and 82 were healthy women. First, a preliminary study identified 29 differentially expressed microRNAs between the two study groups. Next, nine of the differentially expressed microRNAs in the preliminary analysis were evaluated in a new cohort of 67 women with endometriosis and 72 healthy women. Upon validation by quantitative real-time PCR technique, the circulating level of miR-30c-5p was significantly higher in the endometriosis group compared with the healthy women group. The area under the curve value of miR-30c-5p was 0.8437, demonstrating its diagnostic potential even when serum samples registered an acceptable limit of hemolysis. Dysregulation of this microRNA was associated with molecular pathways related to cancer and neuronal processes. We concluded that miR-30c-5p is a potential minimally invasive biomarker of endometriosis, with higher expression in the group of women with endometriosis diagnosed by laparoscopy.

Role of microRNA in Sex Steroid Hormones Signaling and Its Effect in Regulation of Endometrial, Ovarian, and Cervical Cancer: A Literature Review

Worldwide, in 2020, an estimated 417,367 people were diagnosed with uterine cancer. Endometrial cancer accounts for more than 90% of all uterine cancers. The 15th most frequent cancer overall and the sixth most frequent cancer in women is endometrial cancer. Global ovarian cancer Incidence was diagnosed estimated at 313,959 new cases worldwide in 2020. Cervical cancer is the fourth most common malignancy in women worldwide. It has been demonstrated that sex steroid hormones (SSHs) have an essential role in regulating the susceptibility of cancer to cytotoxic therapy. Dysregulation of DNA repair contributes to genomic instability, aberrant cell survival, and cancer development as well as therapy resistance. Several crucial DNA repair components have been discovered to interact with the three main SSHs: androgen, estrogen, and progesterone. MicroRNA (miRNA) dysregulation has been associated with aberrant sex steroid hormone signaling as well as an increased risk of endometrial, cervical, and ovarian cancer. The expression of estrogen and progesterone receptors is modulated by a number of miRNAs, and it has been demonstrated that the miRNA expression profile may predict the way a patient would respond to hormone therapy. Additionally, particular miRNAs have been linked to the control of genes involved in signaling pathways connected to hormones. Recent research has shown that miRNAs can modify hormone signaling pathways and affect the expression of sex steroid hormone receptors. Our goal in this literature review is to present an overview of current knowledge regarding the role of miRNAs in cancers regulated by sex steroid hormone pathways, as well as to identify particular miRNA targets for hormonal therapy.

Progesterone resistance in endometriosis: A pathophysiological perspective and potential treatment alternatives

Background

Endometriosis is a common gynecological disease affecting women of reproductive age. Patients with endometriosis frequently experience severe chronic pain and have higher chances to experience infertility. Progesterone resistance is a major problem that develops during the medical treatment of endometriosis, which often leads to treatment failure of hormonal therapies. Previous studies indicated that the dysregulation of progesterone receptors (PR) is the primary factor leading to progesterone resistance in endometriosis.

Methods

This review article systematically reviewed and summarized findings extracted from previously published papers available on PubMed, encompassing both experimental studies and clinical trials.

Main findings

Various determinants influencing PR expression in endometriosis have been identified, including the environmental toxins, microRNAs, cell signaling pathways, genetic mutations, and the pro-inflammatory cytokines. The selective estrogen/progesterone receptor modulators have emerged as novel therapeutic approaches for treating endometriosis, offering potential improvements in overcoming progesterone resistance.

Conclusion

Concerns and limitations persist despite the newly developed drugs. Therefore, studies on unraveling new therapeutic targets based on the molecular mechanisms of progesterone resistance is warranted for the development potential alternatives to overcome hormonal treatment failure in endometriosis.

TNFα-Induced Altered miRNA Expression Links to NF-κB Signaling Pathway in Endometriosis

Endometriosis is a common gynecological inflammatory disorder characterized by immune system dysregulation, which is involved in lesion initiation and progression. Studies have demonstrated that several cytokines are associated with the evolution of endometriosis, including tumor necrosis factor-α (TNFα). TNFα is a non-glycosylated cytokine protein with potent inflammatory, cytotoxic, and angiogenic potential. In the current study, we examined the ability of TNFα to induce dysregulation of microRNAs (miRNAs) linked to NFkB signaling pathways, thus contributing to the pathogenesis of endometriosis. Using RT-qPCR, the expression of several miRNAs was quantified in primary cells derived from eutopic endometrium of endometriosis subjects (EESC) and normal endometrial stromal cells (NESC), and also TNFα-treated NESCs. The phosphorylation of the pro-inflammatory molecule NF-κB and the candidates of the survival pathways PI3K, AKT, and ERK was measured by western blot analysis. The elevated secretion of TNFα in EESCs downregulates the expression level of several miRNAs significantly in EESCs compared to NESCs. Also, treatment of NESCs with exogenous TNFα significantly reduced the expression of miRNAs in a dose-dependent manner to levels similar to EESCs. In addition, TNFα significantly increased the phosphorylation of the PI3K, AKT, ERK, and NF-κB signaling pathways. Notably, treatment with curcumin (CUR, diferuloylmethane), an anti-inflammatory polyphenol, significantly increased the expression of dysregulated miRNAs in EESC in a dose-dependent manner. Our findings demonstrate that TNFα is upregulated in EESCs, which subsequently dysregulates the expression of miRNAs, contributing to the pathophysiology of endometriotic cells. CUR effectively inhibits the expression of TNFα, subsequently altering miRNA levels and suppressing the phosphorylation of AKT, ERK, and NF-κB.

The Pathological Role of miRNAs in Endometriosis

Association studies investigating miRNA in relation to diseases have consistently shown significant alterations in miRNA expression, particularly within inflammatory pathways, where they regulate inflammatory cytokines, transcription factors (such as NF-κB, STAT3, HIF1α), and inflammatory proteins (including COX-2 and iNOS). Given that endometriosis (EMS) is characterized as an inflammatory disease, albeit one influenced by estrogen levels, it is natural to speculate about the connection between EMS and miRNA. Recent research has indeed confirmed alterations in the expression levels of numerous microRNAs (miRNAs) in both endometriotic lesions and the eutopic endometrium of women with EMS, when compared to healthy controls. The undeniable association of miRNAs with EMS hints at the emergence of a new era in the study of miRNA in the context of EMS. This article reviews the advancements made in understanding the pathological role of miRNA in EMS and its association with EMS-associated infertility. These findings contribute to the ongoing pursuit of developing miRNA-based therapeutics and diagnostic markers for EMS.

MicroRNAs in Endometriosis: Insights into Inflammation and Progesterone Resistance

Endometriosis, a non-malignant gynecological disorder influenced by estrogen, involves the growth of endometrial tissue outside the uterus. Its development includes processes such as inflammation, progesterone resistance, angiogenesis, and cell proliferation. Epigenetic factors, particularly the dysregulation of microRNAs (miRNAs), have emerged as key factors in these mechanisms in endometriosis. This review aims to unveil the intricate molecular processes that control inflammation, progesterone resistance, and miRNA functions in endometriosis. In addition, it provides a comprehensive overview of the current understanding regarding the involvement of miRNAs in the inflammatory aspects of this condition. This synthesis encompasses research investigating the molecular underpinnings of inflammation, along with the biogenesis and roles of miRNAs in endometriosis. Furthermore, it examines human studies and functional analyses to establish the intricate connection between miRNAs, inflammation, and progesterone resistance in the context of endometriosis. The results highlight the significant impact of dysregulated miRNAs on the inflammatory pathways and hormonal imbalances characteristic of endometriosis. Consequently, miRNAs hold promise as potential non-invasive biomarkers and targeted therapeutic agents aimed at addressing inflammation and enhancing the response to progesterone treatment in individuals with endometriosis.

MicroRNA-92a-3p Inhibits Cell Proliferation and Invasion by Regulating the Transcription Factor 21/Steroidogenic Factor 1 Axis in Endometriosis

Endometriosis (EMS) is an estrogen-dependent disease. However, little is known about the regulation of estrogen, a potential therapeutic target, in EMS, which remains very poorly managed in the clinic. We hypothesized that microRNAs (miRNAs) can be exploited therapeutically to regulate transcription factor 21 (TCF21) and steroidogenic factor-1 (SF-1) gene expression. In our study, paired eutopic and ectopic endometrial samples were obtained from women with EMS and processed by a standard protocol to obtain human endometrial stromal cells (EMs) for in vitro studies. We found that miR-92a-3p levels were decreased in ectopic endometrium and ectopic stromal cells (ESCs) compared with paired eutopic lesions. miR-92a-3p overexpression significantly suppressed the proliferation and migration of ESCs, whereas a decreased level of miR-92a-3p generated the opposite results. Next, we identified TCF21 as a candidate target gene of miR-92a-3p. In vitro cell experiments showed that miR-92a-3p negatively regulated the expression of TCF21 and its downstream target gene SF-1. Moreover, cell proliferation and invasion ability decreased after the silencing of SF-1 and increased after SF-1 overexpression. We also observed that silencing SF-1 while inhibiting miR-92a-3p partially blocked the increase in cell proliferation and invasion ability caused by miR-92a-3p knockdown while overexpressing both SF-1 and miR-92a-3p mitigated the impairment in cell proliferation and invasion ability caused by miR-92a-3p overexpression. Our results may provide a novel potential therapeutic target for the treatment of EMS.

TNFα-induced altered miRNA expression links to NF-κB signaling pathway in endometriosis

Endometriosis is a common gynecological inflammatory disorder characterized by immune system dysregulation, which is involved in lesion initiation and progression. Studies have demonstrated that several cytokines are associated with the evolution of endometriosis, including tumor necrosis factor-α (TNFα). TNFα is a non-glycosylated cytokine protein with potent inflammatory, cytotoxic, and angiogenic potential. In the current study, we examined the ability of TNFα to induce dysregulation of microRNAs (miRNAs) linked to NFkB-signaling pathways, thus contributing to the pathogenesis of endometriosis. Using RT-QPCR, the expression of several miRNAs were quantified in primary cells derived from eutopic endometrium of endometriosis subjects (EESC) and normal endometrial stromal cells (NESC) and also TNFα treated NESCs. The phosphorylation of the pro-inflammatory molecule NF-κB and the candidates of the survival pathways PI3K, AKT and ERK was measured by westernblot analysis. The elevated secretion of TNFα in EESCs downregulates the expression level of several miRNAs significantly (p < 0.05) in EESCs compared to NESC. Also treatment of NESCs with exogenous TNFα significantly reduced the expression of miRNAs in a dose-dependent manner to levels similar to EESCs. In addition, TNFα significantly increased the phosphorylation of the PI3K, AKT, ERK, and NF-κB signaling pathways. Notably, treatment with curcumin (CUR, diferuloylmethane), an anti-inflammatory polyphenol, significantly increased the expression of dysregulated miRNAs in EESC in a dose-dependent manner. Our findings demonstrate that TNFα is upregulated in EESCs, which subsequently dysregulates the expression of miRNAs, contributing to the pathophysiology of endometriotic cells. CUR effectively inhibits the expression of TNFα, subsequently altering miRNA levels and suppresses the phosphorylation of AKT, ERK, and NF-κB.

Influence of the ectopic location on the antigen expression and functional characteristics of endometrioma stromal cells

RESEARCH QUESTION

Are the alterations observed in the endometriotic cells, such as progesterone resistance, already present in the eutopic endometrium or acquired in the ectopic location?

DESIGN

The response to decidualization with progesterone and cyclic AMP for up to 28 days was compared in different endometrial stromal cell (EnSC) lines established from samples of endometriomas (eEnSC), eutopic endometrium from women with endometriosis (eBEnSC), endometrial tissue from healthy women (BEnSC) and menstrual blood from healthy donors (mEnSC).

RESULTS

Usual features of decidualized cells, such as changes in cell morphology and expression of prolactin, were similarly observed in the three types of eutopic EnSC studied, but not in the ectopic cells upon decidualization. Among the phenotypic markers analysed, CD105 was down-regulated under decidualization in all cell types (mEnSC, P = 0.005; BEnSC, P = 0.029; eBEnSC, P = 0.022) except eEnSC. mEnSC and BEnSC underwent apoptosis during decidualization, whereas eBEnSC and eEnSC were resistant to the induction of cell death. Lastly, migration studies revealed that mEnSC secreted undetermined factors during decidualization that inhibited cell motility, whereas eEnSC showed a significantly lower ability to produce those migration-regulating factors (P < 0.0001, P  < 0.001 and P = 0.0013 for the migration of mEnSC at 24, 48 and 72 h, respectively; P  < 0.0001 for the migration of eEnSC at all times studied).

CONCLUSIONS

This study provides novel insights into the differences between endometriotic and eutopic endometrial cells and reinforces the idea that the microenvironment in the ectopic location plays additional roles in the acquisition of the alterations that characterize the cells of the endometriotic foci.

miR-297 inhibits expression of progesterone receptor and decidualization in eutopic endometria of endometriosis

AIM

Progesterone resistance is an epigenetic factor that reduces endometrial receptivity and causes implantation failure in women with endometriosis. In addition, dysregulated miRNAs contribute to the underlying pathogenic mechanisms of endometriosis. This study aimed to determine the effect of miR-297 on the progesterone receptor (PR) expression and on insufficient decidualization of endometrial stromal cells (ESCs) within the eutopic endometria of infertile women with minimal or mild endometriosis.

METHODS

ESCs were isolated from infertile endometriosis and normal patients and were transfected with miR-297 mimic or miR-297 inhibitor or respective control. qRT-PCR and western blot were conducted to quantify the expression of miR-297 and PR. The effect of miR-297 on ESCs decidualization was investigated by induced decidualization in vitro.

RESULTS

We observed an increase in miR-297 expression and a decrease in the expression of PR in the ESCs from endometriosis patients. Moreover, the expression of PR, most notably PRB, was found to be downregulated following transfection with miR-297 mimic and upregulated following treatment with miR-297 inhibitor. In addition, overexpressed miR-297 inhibited the decidualization of ESCs in vitro. We further determined that miR-297 exerts direct regulatory effects on PR expression.

CONCLUSIONS

We demonstrated that miR-297 interferes with fertility by repressing the expression of PR and preventing efficient decidualization in eutopic endometria. Further, miR-297 directly contributes to progesterone resistance in minimal or mild cases of endometriosis. Thus, regulation of miR-297 may prove to be a promising therapeutic strategy for endometriosis.

Altered Differential Expression of Genes and microRNAs Related to Adhesion and Apoptosis Pathways in Patients with Different Phenotypes of Endometriosis

We aim to investigate the expression of genes (MAPK1 and CAPN2) and microRNAs (miR-30a-5p, miR-7-5p, miR-143-3p, and miR-93-5p) involved in adhesion and apoptosis pathways in superficial peritoneal endometriosis (SE), deep infiltrating endometriosis (DE), and ovarian endometrioma (OE), and to evaluate whether these lesions share the same pathophysiological mechanisms. We used samples of SE (n = 10), DE (n = 10), and OE (n = 10), and endometrial biopsies of these respective patients affected with endometriosis under treatment at a tertiary University Hospital. Endometrial biopsies collected in the tubal ligation procedure from women without endometriosis comprised the control group (n = 10). Quantitative real-time polymerase chain reaction was performed. The expression of MAPK1 (p < 0.0001), miR-93-5p (p = 0.0168), and miR-7-5p (p = 0.0006) was significantly lower in the SE group than in the DE and OE groups. The expression of miR-30a (p = 0.0018) and miR-93 (p = 0.0052) was significantly upregulated in the eutopic endometrium of women with endometriosis compared to the controls. MiR-143 (p = 0.0225) expression also showed a statistical difference between the eutopic endometrium of women with endometriosis and the control group. In summary, SE showed lower pro-survival gene expression and miRNAs involved in this pathway, indicating that this phenotype has a different pathophysiological mechanism compared to DE and OE.

microRNA-100 shuttled by human umbilical cord MSC-secreted extracellular vesicles induces endometriosis by inhibiting HS3ST2

In recent years, the function of human umbilical cord mesenchymal stem cell-originated extracellular vesicles (hUC-MSC-EVs) on endometriosis has been reported, while its specific mechanisms remain largely unknown. This study aimed at investigating the mechanisms underlying the modulation of EVs harboring miR-100 derived from hUC-MSCs in the growth dynamics of endometrial stromal cells in endometriosis. Endometriosis mouse models were established. miR-100 was upregulated and HS3ST2 was downregulated in endometriosis. Ectopic endometrial tissues and umbilical cord tissues were obtained to extract endometrial stromal cells and hUC-MSCs, from which EVs were isolated. Next, the endometrial stromal cells were co-cultured with hUC-MSC-EVs, during which gain- or loss-of-function approaches were employed for gene overexpression or silencing. The binding affinity among miR-100 and HS3ST2 was identified using multiple assays. It was unveiled that miR-100 could target and inhibit HS3ST2. miR-100 from hUC-MSCs could be transferred into the endometrial stromal cells via EVs. Moreover, miR-100 shuttled by hUC-MSC-EVs facilitated endometrial stromal cell proliferation, invasion, and migration, as well as EMT by inhibiting HS3ST2. In vivo experiments also confirmed that hUC-MSC-derived EVs carrying miR-100 induced the occurrence and development of endometriosis. Collectively, hUC-MSC-EV-loaded miR-100 downregulated HS3ST2 to facilitate the development of endometriosis, which highlights a promising therapeutic target for treating endometriosis.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

Effects of selective inhibition of prostaglandin E2 receptors EP2 and EP4 on the miRNA profile in endometriosis

Endometriosis is an estrogen-dependent, progesterone-resistant, chronic inflammatory gynecological disease of reproductive-age women. Two major clinical symptoms of endometriosis are chronic pelvic pain and infertility, which profoundly affect the quality of life in women. Current hormonal therapies to induce a hypoestrogenic state are unsuccessful because of undesirable side effects, reproductive health concerns, and failure to prevent disease recurrence. Prostaglandin E₂ (PGE₂) plays an important role in the survival and growth of endometriotic lesions. MicroRNAs (miRNAs) are small, noncoding RNAs that control gene expressions through multiple mechanisms and have important roles in the pathogenesis of endometriosis. The objective of the present study is to determine the effects of pharmacological inhibition of PGE₂ receptors, EP2 and EP4, on miRNA profile in endometriosis. The novel results collectively indicate that inhibition of PGE₂-EP2/EP4 signaling regulated several miRNA clusters associated with cell adhesion, migration, invasion, survival and growth in cell-specific and the chromosome-specific manner and reverses the epigenetic silencing of proapoptotic miRNAs 15a and 34c in the human endometriotic epithelial and stromal cells and experimental endometriotic lesions. Thus, selective inhibition of EP2/EP4 receptors could emerge as a potential nonsteroidal therapy for endometriosis.

miRNA-223 expression in patient-derived eutopic and ectopic endometrial stromal cells and its effect on epithelial-to-mesenchymal transition in endometriosis

OBJECTIVE

This study was designed to evaluate the expression of microRNA-223 (miRNA-223) in patient-derived eutopic and ectopic endometrial stromal cells (SCs). Given the fact that miRNA-223 was previously shown to be upregulated in these cells and that this upregulation has been linked to epithelial-to-mesenchymal transition (EMT) during endometriosis, this study aimed to further explore the expression of miRNA-223, its effect in endometriosis, and the mechanisms underlying its effects.

METHODS

Endometrial tissue was collected from 26 patients with endometriosis and 14 patients with hysteromyoma (control group). Primary endometrial SCs were isolated and cultured from several endometrial samples and miRNA-223 expression was evaluated using qRT-PCR. Cells were then transfected with a miRNA-223 overexpression lentiviral vector (sh-miR-223 cells) or an empty control (sh-NC cells) and then used to monitor the effects of miRNA-223 on the expression of several EMT-associated proteins, including N-cadherin, vimentin, and Slug, using western blot. Cellular migration, invasion, and proliferation were then evaluated using a wound healing, Transwell, and CCK-8 assay, respectively. Flow cytometry was used to detect apoptosis.

RESULTS

There was a significant decrease in the expression of miRNA-223 in both eutopic and ectopic endometrial SCs (p < 0.05) whereas upregulation of miRNA-223 inhibited the expression of EMT-related molecules and reduced cell migration, invasion, and proliferation. High levels of miRNA-223 also promoted apoptosis.

CONCLUSION

miRNA-223 expression decreased in endometrial SCs from endometriosis patients, which may facilitate the differential regulation of EMT during endometriosis.

CLINICAL TRIAL REGISTRATION NUMBER

SWYX2020-211.

MicroRNAs Dysregulation as Potential Biomarkers for Early Diagnosis of Endometriosis

Endometriosis is a benign chronic disease in women that is characterized by the presence of active foci of the endometrium or endometrial tissue occurring outside of the uterus. The disease causes disabling symptoms such as pelvic pain and infertility, which negatively affect a patient's quality of life. In addition, endometriosis imposes an immense financial burden on the healthcare system. At present, laparoscopy is the gold standard for diagnosing the disease because other non-invasive diagnostic tests have less accuracy. In addition, other diagnostic tests have low accuracy. Therefore, there is an urgent need for the development of a highly sensitive, more specific, and non-invasive test for the early diagnosis of endometriosis. Numerous researchers have suggested miRNAs as potential biomarkers for endometriosis diagnosis due to their specificity and stability. However, the greatest prognostic force is the determination of several miRNAs, the expression of which varies in a given disease. Despite the identification of several miRNAs, the studies are investigatory in nature, and there is no consensus on them. In the present review, we first provide an introduction to the dysregulation of miRNAs in patients with endometriosis and the potential use of miRNAs as biomarkers in the detection of endometriosis. Then we will describe the role of the mir-200 family in endometriosis. Several studies have shown that the expression of the mir-200 family changes in endometriosis patients, suggesting that they could be used as a diagnostic biomarker and therapeutic target for endometriosis.

Roles of microRNAs in Regulating Apoptosis in the Pathogenesis of Endometriosis

Endometriosis is a gynecologic disorder characterized by the presence of endometrial tissues outside the uterine cavity affecting reproductive-aged women. Previous studies have shown that microRNAs and their target mRNAs are expressed differently in endometriosis, suggesting that this molecule may play a role in the development and persistence of endometriotic lesions. microRNA (miRNA), a small non-coding RNA fragment, regulates cellular functions such as cell proliferation, differentiation, and apoptosis by the post-transcriptional modulation of gene expression. In this review, we focused on the dysregulated miRNAs in women with endometriosis and their roles in the regulation of apoptosis. The dysregulated miRNAs and their target genes in this pathophysiology were highlighted. Circulating miRNAs as potential biomarkers for the diagnosis of endometriosis have also been identified. As shown by various studies, miRNAs were reported to be a potent regulator of gene expression in endometriosis; thus, identifying the dysregulated miRNAs and their target genes could help discover new therapeutic targets for treating this disease. The goal of this review is to draw attention to the functions that miRNAs play in the pathophysiology of endometriosis, particularly those that govern cell death.

Unbiased In Silico Analysis of Gene Expression Pinpoints Circulating miRNAs Targeting KIAA1324, a New Gene Drastically Downregulated in Ovarian Endometriosis

Objective: To identify circulating miRNAs associated with ovarian endometriosis (OMA), and to analyze candidate genes targeted by these miRNAs. Methods: Putative regulating miRNAs were identified through an original bioinformatics approach. We first queried the miRWalk 2.0 database to collect putative miRNA targets. Then, we matched it to a transcriptomic dataset of OMA. Moving from gene expression in the tissue to possible alterations in the patient plasma, a selection of these miRNAs was quantified by qRT-PCR in plasma samples from 93 patients with isolated OMA and 95 patients surgically checked as free from endometriosis. Then, we characterized the genes regulated by more than one miRNA and validated them by immunohistochemistry and transfection experiments on endometrial cell primary cultures obtained from endometrial biopsies of 10 women with and without endometriosis with miRNA mimics. Stromal and epithelial cells were isolated and cultured separately and gene expression levels were measured by RT-qPCR. Results: Eight miRNAs were identified by bioinformatics analysis. Two of them were overexpressed in plasma from OMA patients: let-7b-5p and miR-92a-3p (p < 0.005). Three miRNAs, let-7b and miR-92a-3p, and miR-93-5p potentially targeted KIAA1324, an estrogen-responsive gene and one of the most downregulated genes in OMA. Transfection experiments with mimics of these two miRNAs showed a strong decrease in KIAA1324 expression, up to 40%. Immunohistochemistry revealed a moderate-to-intense staining for KIAA1324 in the eutopic endometrium and a faint-to-moderate staining in the ectopic endometrium for half of the samples, which is concordant with the transcriptomic data. Discussion and Conclusion: Our results suggested that KIAA1324 might be involved in endometriosis through the downregulating action of two circulating miRNAs. As these miRNAs were found to be overexpressed, their quantification in plasma could provide a tool for an early diagnosis of endometriosis.

Identification of potential repurposed drugs for treating endometriosis-associated infertility among women

Endometriosis is the most common gynecological abnormality seen in 10-15% of women of reproductive age, causing infertility in ∼25% of cases, which calls for treatment. Thus, in this study, we have identified miRNAs and genes involved in endometriosis progression, leading to infertility, by performing gene expression analysis followed by pathway analysis and protein-protein networks study. Further, we have predicted repurposed small molecule drugs that will neutralize the regulatory effect of targeting miRNAs that induce sterility in endometriosis. This study predicted two transcription factors, FOXO1, and CREB1, targeted by miRNAs that can be modulated by the repurposed drugs, BRD-K55473186, and methylstat, respectively, for the treatment of infertility due to endometriosis. The former drug seems better and more effective than the other as it showed stronger binding at the active site of FOXO1. These findings provide the rationale for targeting miRNA-regulated transcriptional regulators controlling several biological processes to treat endometriosis and prevent the recurrence of implantation failure or infertility.

Identification of miR-34-3p as a candidate follicular phase serum marker for endometriosis: a pilot study

OBJECTIVE

To identify early follicular phase microribonucleic acids (miRNAs) that are altered in serum of women with endometriosis.

DESIGN

Case-control study.

SETTING

Large university-affiliated in vitro fertilization center.

PATIENT(S)

Women with (n = 21) and without (n = 24) endometriosis.

INTERVENTION(S)

Serum samples were obtained from laparoscopy-confirmed patients with endometriosis.

MAIN OUTCOME MEASURE(S)

The differential expression of serum miRNAs relative to controls was measured using the NanoString nCounter technology and validated by quantitative real-time polymerase chain reaction in an independent cohort of 27 patients with endometriosis and controls (n = 24). Microribonucleic acid target signaling pathways and genes were analyzed bioinformatically. A chemically modified stable miR-34-3p oligonucleotide was used to examine the effect on proliferation of VK2E6/E7 endometrial cells in vitro.

RESULT(S)

Eighteen miRNAs were significantly up-regulated, and 1 miRNA (hsa-miR-34c-3p) was significantly down-regulated in the follicular phase of patients with endometriosis. The analysis of target signaling pathways using TargetScan predicted regulation of the mitogen-activated protein kinase, phosphoinositide 3-kinase/protein kinase B, Hippo, adenosine monophosphate-activated protein kinase, transforming growth factor beta, and endometrial cancer pathways, which have been implicated in the pathogenesis of endometriosis, by these miRNAs. The analysis of sequence complementarity identified prostaglandin E2 receptor 4, interleukin 6 signal transducer, and polo-like kinase 4 genes as possible direct targets of hsa-miR-34-3p. DSDI-1, a chemically modified stable miR-34-3p oligonucleotide, reduced cell proliferation in VK2E6/E7 endometrial cells in vitro.

CONCLUSION(S)

The follicular phase miRNA levels are altered in serum of women with endometriosis and may be useful as reproducible detection biomarkers for early diagnosis of endometriosis. hsa-miR-34-3p is significantly down-regulated in endometriosis, targets endometriosis genes, and reduces endometrial cell proliferation in vitro. These results support hsa-miR-34-3p as a potential therapeutic target in endometriosis.

MALAT1 accelerates proliferation and inflammation and suppresses apoptosis of endometrial stromal cells via the microRNA-142-3p/CXCR7 axis

MALAT1, microRNA (miR)-142-3p, and CXCR7 are critical molecules mediating endometriosis progression, and their correlation in endometriosis has been barely discussed. Thus, this research sought to survey the impact of MALAT1 on endometrial stromal cell (ESC) proliferation, apoptosis, and inflammation via miR-142-3p/CXCR7 axis to promote explorations on endometriosis. In endometrial tissues and ESCs, CXCR7 expression was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analysis and miR-142-3p and MALAT1 expression by qRT-PCR. Then, ESC proliferation was assessed by CCK-8 and EdU labeling assays, apoptosis by flow cytometry, and levels of inflammatory factors tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in ESC supernatant by enzyme linked immunosorbent assay. The interactions among CXCR7, miR-142-3p, and MALAT1 were evaluated by dual luciferase reporter gene, RNA pull-down, and Argonaute 2- RNA immunoprecipitation assays. At last, the relevance of miR-142-3p to MALAT1 and that of miR-142-3p to CXCR7 in ectopic endometrial tissues were analyzed using Pearson correlation analysis. CXCR7 and MALAT1 were overexpressed whilst miR-142-3p was lowly expressed in ectopic endometrial tissues. CXCR7 silencing or miR-142-3p overexpression reduced proliferative ability and enhanced apoptosis rate in ESCs and decreased TNF-α, IL-1β, and IL-6 levels in cell supernatant. miR-142-3p negatively targeted CXCR7 while MALAT1 negatively targeted miR-142-3p. However, MALAT1 silencing diminished ESC proliferation and TNF-α, IL-1β, and IL-6 levels in ESC supernatant and elevated ESC apoptosis, which was counterweighed by inhibiting miR-142-3p. Conclusively, MALAT1 promoted ESC proliferation and inflammatory factor expression and inhibited ESC apoptosis via miR-142-3p/CXCR axis.

Dissecting the miR-451a-Mif Pathway in Endometriosis Pathophysiology Using a Syngeneic Mouse Model: Temporal Expression of Lesion Mif Receptors, Cd74 and Cxcr4

Endometriosis is an enigmatic disease characterized by pain and infertility in which endometrial tissue grows in ectopic locations, predominantly the pelvic cavity. The pathogenesis and pathophysiology of endometriosis is complex and postulated to involve alterations in inflammatory, cell proliferation and post-transcriptional regulatory pathways among others. Our understanding on the pathogenesis and pathophysiology of endometriosis is further complicated by the fact that endometriosis can only be diagnosed by laparoscopy only after the disease has manifested. This makes it difficult to understand the true pathogenesis as a cause-and-effect relationship is difficult to ascertain. To aid in our understanding on endometriosis pathogenesis and pathophysiology, numerous rodent models have been developed. In this case, we discuss further assessment of a miR-451a-macrophage migration inhibitory factor (Mif) pathway which contributes to lesion survival. Specifically, we evaluate the temporal expression of lesion Mif receptors, Cd74 and Cxcr4 using host mice which express wild-type or miR-451a deficient lesions. Similar to that observed in humans and a non-human primate model of endometriosis, Cd74 expression is elevated in lesion tissue in a temporal fashion while that of Cxcr4 shows minimal increase during initial lesion establishment but is reduced later during the lifespan. Absence of miR-451a during initial lesion establishment is associated with an augmentation of Cd74, but no Cxcr4 expression. The data obtained in this study provide further support for a role of Mif receptors, Cd74 and Cxcr4 in the pathophysiology of endometriosis.

miR-203a-3p, ABL1 and TP63 gene expression is altered in the endometrium of women with endometriosis

OBJECTIVE

Many genes and miRNAs have been shown to be associated with the pathogenesis of endometriosis. TP63 (p63) is implicated in lineage specification, proliferative potential, differentiation, cell death and survival. The ABL1 proto-oncogene encodes a cytoplasmic and nuclear protein tyrosine kinase implicated in cell differentiation, cell division, and cell adhesion. Moreover, hsa-miR-203a-3p was reported to play pivotal roles in tumor progression by targeting multiple genes, including ABL1 and TP63. The aim of this study was to investigate the expression of ABL1, TP63, and miR-203a-3p in endometriosis.

METHODS

This study included 30 women with endometriosis (stage III: n = 12 and stage IV: n = 18) and 30 age-matched controls. Total RNA extraction and cDNA synthesis were performed, and a quantitative polymerase chain reaction technique was used to determine the expression of miR-203a-3p, TP63, and ABL1.

RESULTS

TP63 and ABL1 were significantly overexpressed in stages III and IV endometriosis as compared to controls (p < .0001). Moreover, overexpression of ABL1 and TP63 was observed in stage IV compared to stage III (p = .0006 and p = .0002, respectively). Furthermore, significant increase miR-203a-3p expression has been seen in stage IV endometriosis compared to controls (p = .006). The expression of miR-203a-3p in stage III was not significant compared to stage IV and control (p = .33 and p = .43, respectively).

CONCLUSION

It is concluded that miR-203a-3p, ABL1 and TP63 gene expression is altered in the endometrium of patients with endometriosis. It is also suggested that miR-203a-3p, ABL1, and TP63 might be candidate factors for the pathogenesis of endometriosis and suggesting its therapeutic potential in endometriosis.

Exosomal MicroRNA as Biomarkers for Diagnosing or Monitoring the Progression of Ovarian Clear Cell Carcinoma: A Pilot Study

Ovarian cancer is the most common cause of gynecological malignancy-related mortality since early-stage disease is difficult to diagnose. Advanced clear cell carcinoma of the ovary (CCCO) has dismal prognosis, and its incidence has been increasing in Japan, emphasizing the need for highly sensitive diagnostic and prognostic CCCO biomarkers. Exosomal microRNAs (miRNAs) secreted by tumor cells are known to play a role in carcinogenesis; however, their involvement in ovarian cancer is unclear. In this study, we performed expression profiling of miRNAs from exosomes released by five cell lines representing different histological types of ovarian cancer. Exosomes isolated from culture media of cancer and normal cells were compared for miRNA composition using human miRNA microarray. We detected 143 exosomal miRNAs, whose expression was ≥1.5-fold higher in ovarian cancer cells than in the control. Among them, 28 miRNAs were upregulated in cells of all histological ovarian cancer types compared to control, and three were upregulated in CCCO cells compared to other types. Functional analyses indicated that miR-21 overexpressed in CCCO cells targeted tumor suppressor genes PTEN, TPM1, PDCD4, and MASP1. The identified miRNAs could represent novel candidate biomarkers to diagnose or monitor progression of ovarian cancer, particularly CCCO.

Promising therapeutic targets of endometriosis obtained from microRNA studies

Endometriosis is a benign tumor that affect 6-10% women of reproductive age. To date, it is suggested that the aberrant microRNA (miRNA) expressions play important roles in the pathogenesis of endometriosis. Reviewing the literature, we found nine overexpressed miRNAs, which were thoroughly investigated in the context of endometriotic tissues and cells. Most of the overexpressed miRNAs induced endometriosis-specific characteristics including inhibition of apoptosis and decidualization, upregulation of fibrogenesis, invasion, migration, cell proliferation, attachment to extracellular matrix, inflammation, and angiogenesis in the endometriotic cells. Then, we found that the downstream target molecules of these miRNAs, such as early growth response protein-1, extracellular signal-regulated kinase, matrix metallopeptidase 1, signal transducer and activator of transcription 3, cyclooxygenase-2, phosphoinositide 3-kinase, AKT, mammalian target of rapamycin, and vascular endothelial growth factor-A are promising for the therapeutic targets of endometriosis. Recent findings suggest that complex molecular mechanisms leading to development and progression of endometriosis by miRNAs may exist in endometriosis. The meticulous balance between tumorigenic miRNAs and tumoristatic miRNAs may destine the natural course and response to the surgical, medical, and hormonal treatments of this disease. Further investigations into endometriosis-associated miRNAs may elucidate the pathogenesis of endometriosis and help to develop novel therapeutics.

The Relationship and Expression of miR-451a, miR-25-3p and PTEN in Early Peritoneal Endometriotic Lesions and Their Modulation In Vitro

BACKGROUND

miR-451a can function as a tumor suppresser and has been shown to be elevated in both endometriotic lesion tissue and serum from women with endometriosis. To further explore the role of miR-451a in the pathophysiology of endometriosis, specifically, further evaluating its association with the tumor suppressor, phosphatase and tensin homolog (PTEN), we examined their expression in individual endometriotic lesion tissue to gain insight into their relationship and further explore if miR-451a regulates PTEN expression.

METHODS

A total of 55 red, peritoneal endometriotic lesions and matched eutopic endometrial specimens were obtained from 46 patients with endometriosis. miR-451a, miR-25-3p and PTEN mRNA levels were assessed by qRT-PCR and reported for each matched eutopic and ectopic sample. To evaluate miR-451a and miR-25-3p expression of miR-25-3p and PTEN, respectively, 12Z cells (endometriotic epithelial cell line) were transfected and miR-25-3p expression was assessed by qRT-PCR, while PTEN protein expression was assessed by Western blotting.

RESULTS

PTEN and miR-25-3p expression exhibited an inverse relationship, as did miR-25-3p and miR-451a in individual lesions. Over-expression of miR-451a in 12Z cells resulted in down-regulation of miR-25-3p, while up-regulation of miR-25-3p resulted in down-regulation of PTEN protein expression.

CONCLUSIONS

By assessing individual endometriotic lesion expression, we discovered an inverse relationship between miR-451a, miR-25-3p and PTEN, while in vitro cell transfection studies suggest that miR-451a may regulate PTEN expression via modulating miR-25-3p.