MicroRNA expression profile in endometriosis: its relation to angiogenesis and fibrinolytic factors

Targeting NGF but not VEGFR1 or BDNF signaling reduces endometriosis-associated pain in mice

INTRODUCTION

Endometriosis is a chronic inflammatory disease that affects ∼10 % of women. A significant fraction of patients experience limited or no efficacy with current therapies. Tissue adjacent to endometriosis lesions often exhibits increased neurite and vascular density, suggesting that disease pathology involves neurotrophic activity and angiogenesis.

OBJECTIVES

We aim to evaluate the potential for key tyrosine-kinase-receptor-coupled neurotrophic molecules to contribute to endometriosis-associated pain in mice.

METHODS

Peritoneal fluid was collected from endometriosis patients undergoing surgery and the levels of NGF and VEGFR1 regulators (VEGFA, VEGFB, PLGF, and sVEGFR1) were quantified by ELISA. VEGFR1 regulator concentrations were used to calculate VEGFR1 occupancy. We used genetic depletion, neutralizing antibodies, and pharmacological approaches to specifically block neurotrophic ligands (NGF or BDNF) or receptors (VEGFR1, TRKs) in a murine model of endometriosis-associated pain. Endometriosis-associated pain was measured using von Frey filaments, quantification of spontaneous abdominal pain-related behavior, and thermal discomfort. Disease parameters were evaluated by lesion size and prevalence. To evaluate potential toxicity, we measured the effect of entrectinib dose and schedule on body weight, liver and kidney function, and bone structure (via micro-CT).

RESULTS

We found that entrectinib (pan-Trk inhibitor) or anti-NGF treatments reduced evoked pain, spontaneous pain, and thermal discomfort. In contrast, even though calculated receptor occupancy revealed that VEGFR1 agonist levels are sufficient to support signaling, blocking VEGFR1 via antibody or tamoxifen-induced knockout did not reduce pain or lesion size in mice. Targeting BDNF-TrkB with an anti-BDNF antibody also proved ineffective. Notably, changing dosing schedule to once weekly eliminated entrectinib-induced bone-loss without decreasing efficacy against pain.

CONCLUSIONS

This suggests NGF-TrkA signaling, but not BDNF-TrkB or VEGF-VEGFR1, mediates endometriosis-associated pain. Moreover, entrectinib blocks endometriosis-associated pain and reduces lesion sizes. Our results also indicated that entrectinib-like molecules are promising candidates for endometriosis treatment.

Selection of reference miRNAs for RT-qPCR assays in endometriosis menstrual blood-derived mesenchymal stem cells

Choosing appropriate reference genes or internal controls to normalize RT-qPCR data is mandatory for the interexperimental reproducibility of gene expression data obtained by RT-qPCR in most studies, including those on endometriosis. Particularly for miRNAs, the choice for reference genes is challenging because of their physicochemical and biological characteristics. Moreover, the retrograde menstruation theory, mesenchymal stem cells in menstrual blood (MenSCs), and changes in post-transcriptional regulatory processes through miRNAs have gained prominence in the scientific community as important players in endometriosis. Therefore, we originally explored the stability of 10 miRNAs expressions as internal control candidates in conditions involving the two-dimensional culture of MenSCs from healthy women and patients with endometriosis. Here, we applied multiple algorithms (geNorm, NormFinder, Bestkeeper, and delta Ct) to screen reference genes and assessed the comprehensive stability classification of miRNAs using RefFinder. Pairwise variation calculated using geNorm identified three miRNAs as a sufficient number of reference genes for accurate normalization. MiR-191-5p, miR-24-3p, and miR-103a-3p were the best combination for suitable gene expression normalization. This study will benefit similar research, but is also attractive for regenerative medicine and clinics that use MenSCs, miRNA expression, and RT-qPCR.

MiR-424-5p Inhibits Proliferation, Migration, Invasion and Angiogenesis of the HTR-8/SVneo Cells Through Targeting LRP6 Mediated β-catenin

The aim of this study was to investigate the effects of miR-424-5p on biological behaviors and angiogenesis of the HTR-8/SVneo Cells. Our study included 60 parturient women, which were divided into an PA group (placenta accreta, n = 30) and a normal group (normal placenta, n = 30). QPCR was used to measure the expression of miR-424-5p in placental tissues. The effects of the miR-424-5p mimic on proliferation, migration, and invasion of human HTR-8/SVneo cells and angiogenesis were analyzed. The potential modulated relationship between miR-424-5p and low-density lipoprotein receptor-related protein-6 (LRP6) was demonstrated by luciferase assay. The expression of LRP6, β-catenin, matrix metalloproteinase-2 (MMP-2), placental growth factor (PGF) and vascular endothelial growth factor (VEGF) were measured by qPCR and Western blot assays. The expression of miR-424-5p in the PA group was significantly decreased than that in the normal group. The expression of miR-424-5p has negative correlation with blood loss. Upregulation of miR-424-5p significantly suppressed the cell proliferation, migration, and invasion of HTR-8/SVneo cells in vitro, as well as the tube formation of human umbilical vein endothelial cells (HUVECs). The luciferase assay demonstrated that LRP6 was a target of miR-424-5p. The expression of LRP6, β-catenin, MMP-2, PGF and VEGF were also decreased with upregulation of miR-424-5p (p < 0.05). The inhibitory effects of miR-424-5p on HTR-8/SVneo cells and angiogenesis were enhanced by downregulation of LRP6, but were reversed by upregulation of LRP6. The present study suggests that downregulation of miR-424-5p is related to the occurrence of PA. Enhancing miR-424-5p inhibits proliferation, migration, invasion and angiogenesis of the HTR-8/SVneo cells through targeting LRP6 mediated β-catenin, providing more insights about PA.

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.

The Different Gene Expression Profile in the Eutopic and Ectopic Endometrium Sheds New Light on the Endometrial Seed in Endometriosis

The changes in endometrial cells, both in the eutopic endometrium of patients with and without endometriosis and in lesions at ectopic sites, are frequently described and often compared to tumorigenesis. In tumorigenesis, the concept of "seed and soil" is well established. The seed refers to tumor cells with metastatic potential, and the soil is any organ or tissue that provides a suitable environment for the seed to grow. In this systematic review (PRISMA-S), we specifically compared the development of endometriosis with the "seed and soil" hypothesis. To determine changes in the endometrial seed, we re-analyzed the mRNA expression data of the eutopic and ectopic endometrium, paying special attention to the epithelial-mesenchymal transition (EMT). We found that the similarity between eutopic endometrium without and with endometriosis is extremely high (~99.1%). In contrast, the eutopic endometrium of patients with endometriosis has a similarity of only 95.3% with the ectopic endometrium. An analysis of EMT-associated genes revealed only minor differences in the mRNA expression levels of claudin family members without the loss of other cell-cell junctions that are critical for the epithelial phenotype. The array data suggest that the changes in the eutopic endometrium (=seed) are quite subtle at the beginning of the disease and that most of the differences occur after implantation into ectopic locations (=soil).

New insights about endometriosis-associated ovarian cancer: pathogenesis, risk factors, prediction and diagnosis and treatment

Previous studies have shown that the risk of malignant transformation of endometriosis in premenopausal women is approximately 1%, significantly impacting the overall well-being and quality of life of affected women. Presently, the diagnostic gold standard for endometriosis-associated ovarian cancer (EAOC) continues to be invasive laparoscopy followed by histological examination. However, the application of this technique is limited due to its high cost, highlighting the importance of identifying a non-invasive diagnostic approach. Therefore, there is a critical need to explore non-invasive diagnostic methods to improve diagnostic precision and optimize clinical outcomes for patients. This review presents a comprehensive survey of the current progress in comprehending the pathogenesis of malignant transformation in endometriosis. Furthermore, it examines the most recent research discoveries concerning the diagnosis of EAOC and emphasizes potential targets for therapeutic intervention. The ultimate objective is to improve prevention, early detection, precise diagnosis, and treatment approaches, thereby optimizing the clinical outcomes for patients.

Interactions between miRNAs and the Wnt/β-catenin signaling pathway in endometriosis

Endometriosis is a disease characterized by the ectopic growth of endometrial tissue (glands and stroma) outside the confines of the uterus and often involves vital organs such as the intestines and urinary system. Endometriosis is considered a refractory disease owing to its enigmatic etiology, propensity for recurrence following conservative or surgical interventions, and the absence of radical treatment and long-term management. In recent years, the incidence of endometriosis has gradually increased, rendering it a pressing concern among women of childbearing age. A more profound understanding of its pathogenesis can significantly improve prognosis. Recent research endeavors have spotlighted the molecular mechanisms by which microRNAs (miRNAs) regulate the occurrence and progression of endometriosis. Many miRNAs have been reported to be aberrantly expressed in the affected tissues of both patients and animal models. These miRNAs actively participate in the regulation of inflammatory reactions, cellular proliferation, angiogenesis, and tissue remodeling. Their capacity to modulate crucial signaling pathways, such as the Wnt/β-catenin signaling pathway, reinforces their potential utility as diagnostic markers or therapeutic agents for endometriosis. In this review, we provide the latest insights into the role of miRNAs that interact with the Wnt/β-catenin pathway to regulate the biological behaviors of endometriosis cells and disease-related symptoms, such as pain and infertility. We hope that this review will provide novel insights and promising targets for innovative therapies addressing endometriosis.

Differential microRNA Expression Analysis in Patients with HPV-Infected Ovarian Neoplasms

This study aimed to identify microRNAs (miRNAs) whose expression levels are altered by high-risk human papillomavirus (HR-HPV) infection in women with epithelial ovarian neoplasms. MiRNA expression was quantified by real-time polymerase chain reaction, while HR-HPV DNA was quantified using digital-droplet PCR. Analysis of 11 miRNAs demonstrated significantly lower hsa-miR-25-5p expression in HPV-infected compared to uninfected ovarian tissues (p = 0.0405), while differences in miRNA expression in corresponding serum were statistically insignificant. The expression of hsa-miR-218-5p in ovarian tumors was significantly higher in high-grade serous ovarian carcinoma (HGSOC) cases than in other neoplasms (p = 0.0166). In addition, hsa-miR-218-5p was significantly upregulated, whereas hsa-miR-191-5p was significantly downregulated in tissues with stage III/IV FIGO (p = 0.0009 and p = 0.0305, respectively). Using unsupervised clustering, we identified three unique patient groups with significantly varied frequencies of HPV16/18-positive samples and varied miRNA expression profiles. In multivariate analysis, high expression of hsa-miR-16-5p was an independent prognostic factor for poor overall survival (p = 0.0068). This preliminary analysis showed the changes in miRNA expression in ovarian neoplasms during HPV infection and those collected from HGSOCs or patients with advanced disease. This prospective study can provide new insights into the pathogenesis of ovarian neoplasms and host-virus interactions.

MLLT11 Regulates Endometrial Stroma Cell Adhesion, Proliferation and Survival in Ectopic Lesions of Women with Advanced Endometriosis

MLLT11 is a gene implicated in cell differentiation and the development and progression of human cancers, but whose role in the pathogenesis of endometriosis is still unknown. Using quantitative RT-PCR and immunohistochemistry, we analyzed 37 women with and 33 women without endometriosis for differences in MLLT11 expression. We found that MLLT11 is reduced in the ectopic stroma cells of women with advanced stage endometriosis compared to women without endometriosis. MLLT11 knockdown in control stroma cells resulted in the downregulation of their proliferation accompanied by G1 cell arrest and an increase in the expression of p21 and p27. Furthermore, the knockdown of MLLT11 was associated with increased apoptosis resistance to camptothecin associated with changes in BCL2/BAX signaling. Finally, MLLT11 siRNA knockdown in the control primary stroma cells led to an increase in cell adhesion associated with the transcriptional activation of ACTA2 and TGFB2. We found that the cellular phenotype of MLLT11 knockdown cells resembled the phenotype of the primary endometriosis stroma cells of the lesion, where the levels of MLLT11 are significantly reduced compared to the eutopic stroma cells of women without the disease. Overall, our results indicate that MLLT11 may be a new clinically relevant player in the pathogenesis of endometriosis.

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.

Impact of Continuous Estroprogestin Treatment on Circulating Microparticle Levels in Deep Endometriosis Patients

There has been increasing interest in the study of new pathogenic mechanisms in endometriosis (END), including the coagulation/fibrinolysis system and its link with inflammation and tissue remodeling. It has been suggested that END patients, especially with deep-infiltrating (DE) forms, could present a hypercoagulable state revealing higher levels of proinflammatory and procoagulant markers, such as total circulating microparticles (cMPs) and cMP-TF (tissue factor), released by cells in response to damage, activation, or apoptosis. However, no previous study has assessed the effect of END hormonal treatments on cMP and cMP-TF levels. Therefore, the aim of this study was to evaluate the impact of these treatments on cMP and cMP-TF levels in DE patients. Three groups were compared: DE patients receiving a continuous combined oral contraceptive regimen (CCOCR) (n = 41), DE patients without CCOCR (n = 45), and a control group (n = 43). cMP and cMP-TF levels were evaluated in platelet-free plasma. A significant decrease in the total cMP levels was found in the DE group with CCOCR versus the group without CCOCR, reflecting a higher chronic inflammatory status in DE patients that decreased with the treatment. cMP-TF levels were higher in DE patients receiving CCOCR versus those not receiving CCOCR, suggesting that treatments containing estrogens play a predominant role in suppressing the inhibitory pathway of TF.

Macrophages and small extracellular vesicle mediated-intracellular communication in the peritoneal microenvironment: Impact on endometriosis development

Endometriosis is an inflammatory disease that is defined as the growth of endometrium-like tissue outside the uterus, commonly on the lining of the pelvic cavity, visceral organs and in the ovaries. It affects around 190 million women of reproductive age worldwide and is associated with chronic pelvic pain and infertility, which greatly impairs health-related life quality. The symptoms of the disease are variable, this combined with a lack of diagnostic biomarkers and necessity of surgical visualisation to confirm disease, the prognosis can take an average timespan of 6–8 years. Accurate non-invasive diagnostic tests and the identification of effective therapeutic targets are essential for disease management. To achieve this, one of the priorities is to define the underlying pathophysiological mechanisms that contribute to endometriosis. Recently, immune dysregulation in the peritoneal cavity has been linked to endometriosis progression. Macrophages account for over 50% of immune cells in the peritoneal fluid and are critical for lesion growth, angiogenesis, innervation and immune regulation. Apart from the secretion of soluble factors like cytokines and chemokines, macrophages can communicate with other cells and prime disease microenvironments, such as the tumour microenvironment, via the secretion of small extracellular vesicles (sEVs). The sEV-mediated intracellular communication pathways between macrophages and other cells within the peritoneal microenvironment in endometriosis remain unclear. Here, we give an overview of peritoneal macrophage (pMΦ) phenotypes in endometriosis and discuss the role of sEVs in the intracellular communication within disease microenvironments and the impact they may have on endometriosis progression.

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.

miR-424-5p combined with miR-17-5p has high diagnostic efficacy for endometriosis

PURPOSE

Endometriosis (EMT) is a chronic benign disease with high prevalence. This study investigated the diagnostic value of serum miR-17-5p, miR-424-5p, and their combined expressions for EMT.

METHODS

Total 80 EMT patients of reproductive age who underwent laparoscopy or laparotomy and were confirmed by pathological examination were included as the study subjects, and another 80 healthy women of reproductive age receiving gynecological examination and ultrasonography with no pelvic abnormalities were selected as the control group. The whole blood samples of enrolled subjects were collected and clinical characteristics were recorded. The miR-17-5p, miR-424-5p, VEGFA, IL-4, and IL-6 levels in the serum were measured. ROC curve was used to evaluate the diagnostic efficacy of miR-17-5p and miR-424-5p expressions for EMT. Pearson correlation was performed to analyze the correlation of miR-17-5p and miR-424-5p with clinical indexes in EMT patients.

RESULTS

miR-17-5p and miR-424-5p were downregulated in EMT patients. For diagnosing EMT, the AUC of miR-17-5p was 0.865 and cutoff value was 0.890 (91.3% sensitivity and 85% specificity), the AUC of miR-424-5p was 0.737, and cutoff value was 0.915 (98.8% sensitivity and 61.2% specificity), and the AUC of miR-424-5p combined with miR-17-5p was 0.938 and cutoff value was 2.205 (93.8% sensitivity and 88.7% specificity), with the diagnostic efficacy higher than miR-424-5p or miR-17-5p alone. miR-17-5p and miR-424-5p expressions were negatively correlated with dysmenorrhea, infertility, pelvic pain, and rASRM stage, but not with age, BMI, menstrual disorder, and nulliparity. VEGFA, IL-4, IL-6, and CA-125 were increased in EMT patients and were inversely associated with miR-17-5p and miR-424-5p.

CONCLUSION

miR-424-5p combined with miR-17-5p has high diagnostic efficacy for EMT.

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.

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.

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.

Pathogenesis of Human Adenomyosis: Current Understanding and Its Association with Infertility

The aim of this review article was to summarize our current understanding on the etiologies and pathogenesis of human adenomyosis and to clarify the relative association between adenomyosis and infertility. The exact pathogenesis of adenomyosis is still elusive. Among different reported concepts, direction invagination of gland cells from the basalis endometrium deep into myometrium is the most widely accepted opinion on the development of adenomyosis. According to this concept, endometrial epithelial cells and changed fibroblasts, abnormally found in the myometrium in response to repeated tissue injury and/or disruption at the endometrium-myometrium interface (EMI), elicit hyperplasia and hypertrophy of the surrounding smooth muscle cells. In this review, a comprehensive review was performed with a literature search using PubMed for all publications in English and Japanese (abstract in English), related to adenomyosis and infertility, from inception to April 2021. As an estrogen-regulated factor, hepatocyte growth factor (HGF) exhibits multiple functions in endometriosis, a disease commonly believed to arise from the functionalis endometrium. As a mechanistic basis of gland invagination, we investigated the role of HGF, either alone or in combination with estrogen, in the occurrence of epithelial-mesenchymal transition (EMT) in adenomyosis. Aside from microtrauma at the EMI, metaplasia of displaced Müllerian remnants, differentiation of endometrial stem/progenitor cells within the myometrium and somatic mutation of some target genes have been put forward to explain how adenomyosis develops. In addition, the possible role of microRNAs in adenomyosis is also discussed. Besides our knowledge on the conventional classification (focal and diffuse), two recently proposed classifications (intrinsic and extrinsic) of adenomyosis and the biological differences between them have been described. Although the mechanistic basis is unclear, the influence of adenomyosis on fertility outcome is important, especially considering the recent tendency to delay pregnancy among women. Besides other proposed mechanisms, a recent transmission election microscopic (TEM) study indicated that microvilli damage and an axonemal alteration in the apical endometria of human adenomyosis, in response to endometrial inflammation, may be involved in negative fertility outcomes. We present a critical analysis of the literature data concerning the mechanistic basis of infertility in women with adenomyosis and its impact on fertility outcome.

Identification of miRNA signature for predicting the prognostic biomarker of squamous cell lung carcinoma

As explorations deepen, the role of microRNAs (miRNAs) in lung squamous cell carcinoma (LUSC), from its emergence to metastasis and prognosis, has elicited extensive concern. LUSC-related miRNA and mRNA samples were acquired from The Cancer Genome Atlas (TCGA) database. The data were initially screened and pretreated, and the R platform and series analytical tools were used to identify the specific and sensitive biomarkers. Seven miRNAs and 15 hub genes were found to be closely related to the overall survival of patients with LUSC. Determination of the expression of these miRNAs can help improve the overall survival of LUSC patients. The 15 hub genes correlated with overall survival (OS). The new miRNA markers were identified to predict the prognosis of LUSC. The findings of this study offer novel views on the evolution of precise cancer treatment approaches with high reliability.

Overexpression of miR-200b-3p in Menstrual Blood-Derived Mesenchymal Stem Cells from Endometriosis Women

The key relationship between Sampson's theory and the presence of mesenchymal stem cells in the menstrual flow (MenSCs), as well as the changes in post-transcriptional regulatory processes as actors in the etiopathogenesis of endometriosis, are poorly understood. No study to date has investigated the imbalance of miRNAs in MenSCs related to the disease. Thus, through literature and in silico analyses, we selected four predicted miRNAs as regulators of EGR1, SNAI1, NR4A1, NR4A2, ID1, LAMC3, and FOSB involved in pathways of apoptosis, angiogenesis, response to steroid hormones, migration, differentiation, and cell proliferation. These genes are frequently overexpressed in the endometriosis condition in our group studies. They were the trigger for the miRNAs search. Therefore, a case-control study was conducted with MenSCs of women with and without endometriosis (ten samples per group). Crossing information obtained from the STRING, PubMed, miRPathDB, miRWalk, and DIANA TOOLS databases, we chose to explore the expression of miR-21-5p, miR-100-5p, miR-143-3p, and miR-200b-3p by RT-qPCR. We found an upregulation of the miR-200b-3p in endometriosis MenSCs (P = 0.0207), with a 7.93-fold change (ratio of geometric means) compared to control. Overexpression of miR-200b has been associated with increased cell proliferation, stemness, and accentuated mesenchymal-epithelial transition process in eutopic endometrium of endometriosis. We believe that dysregulated miR-200b-3p may establish primary changes in the MenSCs, thus favoring tissue implantation at the ectopic site.

Blood tests for prediction of deep endometriosis: A case-control study

BACKGROUND

Deep endometriosis (DE) is the most aggressive subtype of endometriosis. The diagnosis may be challenging, and no biomarkers that can discriminate women with DE from those without DE have been developed.

AIM

To evaluate the role of blood hemostatic parameters and inflammatory indices in the prediction of DE.

METHODS

This case-control study was performed at the Women’s Hospital, Zhejiang University School of Medicine between January 2015 and December 2016. Women with DE and women with benign gynecologic disease (control group) eligible for gynecological surgery were enrolled. Routine plasma hemostatic parameters and inflammatory indices were obtained before surgery. Univariate and multivariate analysis were performed. Receiver operating characteristic (ROC) curves were generated, and areas under the curve (AUC) were calculated to assess the predictive values of the selected parameters.

RESULTS

A total of 126 women were enrolled, including 31 with DE and 95 controls. Plasma fibrinogen (Fg, P < 0.01), international normalized ratio (P < 0.05), and C-reactive protein levels (P < 0.01) were significantly higher in women with DE compared with controls. Plasma hemoglobin (HB) levels (P < 0.05) and shortened thrombin time (P < 0.05) were significantly lower in women with DE than in controls. Plasma Fg levels [adjusted OR (aOR) 2.12, 95%confidence interval (CI): 1.31-3.75] and plasma HB levels (aOR 0.48, 95%CI: 0.29-0.78) were significantly associated with DE (both P < 0.05). ROC analysis showed that the diagnostic value of Fg or HB alone for DE was limited. The AUC of the combination of both markers as a dual marker index was 0.773 with improved sensitivity (67.7%) and specificity (78.9%) at cutoffs of 3.09 g/L and 126 g/L, respectively.

CONCLUSION

The combination of Fg and HB was a reliable predictor of DE. A larger study is needed to confirm the findings.

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.

Role of repressed microRNAs in endometriosis

Endometriosis is a common, estrogen-dependent benign tumor that affect 3-10% women of reproductive age, and is characterized by the ectopic growth of endometrial tissue, which is found primarily in the rectovaginal septum, ovaries, and pelvic peritoneum. To date, accumulating evidence suggests that various epigenetic aberrations, including the expression of aberrant microRNAs (miRNAs), play definite roles in the pathogenesis of endometriosis. This review summarizes the recent findings on the aberrantly repressed miRNAs, as well as their potential roles regarding the pathogenesis of endometriosis.

Circulating miRNAs Related to Epithelial-Mesenchymal Transitions (EMT) as the New Molecular Markers in Endometriosis

Endometriosis is a chronic gynecological disease defined by the presence of endometrial-like tissue found outside the uterus, most commonly in the peritoneal cavity. Endometriosis lesions are heterogenous but usually contain endometrial stromal cells and epithelial glands, immune cell infiltrates and are vascularized and innervated by nerves. The complex etiopathogenesis and heterogenity of the clinical symptoms, as well as the lack of a specific non-invasive diagnostic biomarkers, underline the need for more advanced diagnostic tools. Unfortunately, the contribution of environmental, hormonal and immunological factors in the disease etiology is insufficient, and the contribution of genetic/epigenetic factors is still fragmentary. Therefore, there is a need for more focused study on the molecular mechanisms of endometriosis and non-invasive diagnostic monitoring systems. MicroRNAs (miRNAs) demonstrate high stability and tissue specificity and play a significant role in modulating a range of molecular pathways, and hence may be suitable diagnostic biomarkers for the origin and development of endometriosis. Of these, the most frequently studied are those related to endometriosis, including those involved in epithelial–mesenchymal transition (EMT), whose expression is altered in plasma or endometriotic lesion biopsies; however, the results are ambiguous. Specific miRNAs expressed in endometriosis may serve as diagnostics markers with prognostic value, and they have been proposed as molecular targets for treatment. The aim of this review is to present selected miRNAs associated with EMT known to have experimentally confirmed significance, and discuss their utility as biomarkers in endometriosis.

LncRNA AFAP1-AS1 regulates proliferation and apoptosis of endometriosis through activating STAT3/TGF-β/Smad signaling via miR-424-5p

AIM

Endometriosis is a common gynecological disorder characterized by chronic pelvic pain and infertility, which negatively affects women's health worldwide. AFAP1-AS1 has been implicated in endometriosis lesions recently, but its mechanism of endometriosis progression remains unclear.

METHODS

Endometrial stromal cells (ESCs) were used to identify the role of AFAP1-AS1 in endometriosis. The migratory capability was determined by transwell. Gene and protein expressions were identified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Cell viability and apoptosis were detected by MTT assays and flow cytometry, respectively. Luciferase report assays were used to identify the interaction of AFAP1-AS1, miR-424-5p and signal transducer and activator of transcription 3 (STAT3).

RESULTS

AFAP1-AS1 knockdown or miR-424-5p overexpression inhibited proliferation and migration, and promoted apoptosis in ESCs. In addition, knockdown of AFAP1-AS1 repressed the expression of ki-67 and Bcl-2, and promoted the levels of cleaved caspase-3 and Bax. Furthermore, knockdown of AFAP1-AS1 inhibited the conversion of E-cadherin to N-cadherin and the expression of Snail. Moreover, AFAP1-AS1 activated the STAT3/transforming growth factor-β1 (TGF-β1)/Smad2 axis via directly targeting miR-424-5p. The regulatory effect of AFAP1-AS1 silencing in ESC migration, proliferation, and apoptosis was reversed by miR-424-5p inhibition or STAT3 overexpression.

CONCLUSIONS

AFAP1-AS1 silencing could inhibit cell proliferation and promote apoptosis by regulating STAT3/TGF-β/Smad signaling pathway via targeting miR-424-5p in ESCs. AFAP1-AS1 may be a potential therapeutic target of controlling the progression of endometriosis.

Clinical consequences of defective decidualization

Decidualization is characterized by a series of genetic, metabolic, morphological, biochemical, vascular and immune changes occurring in the endometrial stroma in response to the implanting embryo or even before conception and involves the stromal cells of the endometrium. It is a fundamental reproductive event occurring in mammalian species with hemochorial placentation. A growing body of experimental and clinical evidence strongly suggests that defective or disrupted decidualization contributes to the establishment of an inappropriate maternal-fetal interface. This has relevant clinical consequences, ranging from recurrent implantation failure and recurrent pregnancy loss in early pregnancy to several significant complications of advanced gestation. Moreover, recent evidence indicates that selected diseases of the endometrium, such as chronic endometritis and endometriosis, can have a detrimental impact on the decidualization response in the endometrium and may help explain some aspects of the reduced reproductive outcome associated with these conditions. Further research efforts are needed to fully understand the biomolecular mechanisms ans events underlying an abnormal decidualization response. This will permit the development of new diagnostic and therapeutic strategies aimed to improve the likelihood of achieveing a successful pregnancy.

Exosomes and their cargo are important regulators of cell function in endometriosis

Endometriosis is a chronic oestrogen-dependent gynaecological disorder characterized by non-menstrual pelvic pain, infertility and the extrauterine growth of endometrial-like glands and stroma. It has been noted that the eutopic endometrium of women with endometriosis is functionally distinct from that of women without endometriosis. Moreover, ectopic endometrial implants are functionally different from the eutopic endometrium of women with endometriosis. However, the mechanisms directing these differences are ill-defined. It is proposed here that small membrane-bound extracellular vesicles called exosomes are important vehicles in the protection and transport of signalling molecules central to the dysregulation of endometrial function in women with endometriosis. Therefore, a critical review of the literature linking exosomes and their cargo to the pathobiology of endometriosis was conducted. Circulating peritoneal fluid and endometrial cell exosomes contained long non-coding RNA, miRNA and proteins involved in histone modification, angiogenesis and immune modulation that differed significantly in women with endometriosis compared with controls. Moreover, experimental evidence supports a role for exosomes and their cargo in angiogenesis, neurogenesis, immune modulation and endometrial stromal cell invasion. It is therefore suggested that exosomes play an important role in the pathophysiology of endometriosis.

Overview of miRNAs for the non-invasive diagnosis of endometriosis: evidence, challenges and strategies. A systematic review

OBJECTIVE

The aim of the study was to assess the evidence on miRNAs as biomarkers for the diagnosis of endometriosis, as well as to provide insights into the challenges and strategies associated with the use of these molecules as accessible tools in clinical practice.

METHODS

Systematic review conducted on PubMed®, Latin American and Caribbean Health Sciences Literature (LILACS), MEDLINE® and Web of Science databases using the search terms endometriosis (all fields) AND miRNA (all fields), evaluating all publication up to May 2019.

RESULTS

Most miRNAs found to be dysregulated in this study were harvested from tissue samples, which precludes their use as a non-invasive diagnostic test. However, differential expression of 62 miRNAs was reported in samples that may be used for non-invasive diagnosis of endometriosis, such as blood, serum and plasma.

CONCLUSION

Despite the identification of several candidates, studies are investigatory in nature and have been conducted with small number of samples. Also, no particular miRNA has been validated for diagnostic purposes so far. Studies based primarily on biological samples and applicable to translational research are warranted. Large databases comprising information on sample type and the use of saliva and vaginal fluid for miRNAs identification may prove essential to overcome current barriers to diagnosis of endometriosis.

Identification of a MicroRNA Signature Associated With Lymph Node Metastasis in Endometrial Endometrioid Cancer

Background

Lymph node metastasis (LNM) is an important prognostic factor in endometrial cancer. Anomalous microRNAs (miRNAs) are associated with cell functions and are becoming a powerful tool to characterize malignant transformation and metastasis. The aim of this study was to construct a miRNA signature to predict LNM in endometrial endometrioid carcinoma (EEC).

Method

Candidate target miRNAs related to LNM in EEC were screened by three methods including differentially expressed miRNAs (DEmiRs), weighted gene co-expression network analysis (WGCNA), and decision tree algorithms. Samples were randomly divided into the training and validation cohorts. A miRNA signature was built using a logistic regression model and was evaluated by the area under the curve (AUC) of receiver operating characteristic curve (ROC) and decision curve analysis (DCA). We also conducted pathway enrichment analysis and miRNA-gene regulatory network to look for potential genes and pathways engaged in LNM progression. Survival analysis was performed, and the miRNAs were tested whether they expressed differently in another independent GEO database.

Result

Thirty-one candidate miRNAs were screened and a final 15-miRNA signature was constructed by logistic regression. The model showed good calibration in the training and validation cohorts, with AUC of 0.824 (95% CI, 0.739-0.912) and 0.821 (95% CI, 0.691-0.925), respectively. The DCA demonstrated the miRNA signature was clinically useful. Hub miRNAs in signature seemed to contribute to EEC progression via mitotic cell cycle, cellular protein modification process, and molecular function. MiR-34c was statistically significant in survival that a higher expression of miR-34c indicated a higher survival time. MiR-34c-3p, miR-34c-5p, and miR-34b-5p were expressed differentially in GSE75968.

Conclusion

The miRNA signature could work as a noninvasive method to detect LNM in EEC with a high prediction accuracy. In addition, miR-34c cluster may be a key biomarker referring LNM in endometrial cancer.

Down-regulation of Exosomal miR-214-3p Targeting CCN2 Contributes to Endometriosis Fibrosis and the Role of Exosomes in the Horizontal Transfer of miR-214-3p

Endometriosis (EMs) is defined as the presence of tissue which somewhat resembles endometrial glands and stroma outside the uterus, and elicits fibrosis. Fibrosis is the main factor resulting in pain and infertility, while the aetiology of endometrial fibrosis is unknown. There is strong evidence from numerous experiments showing that connective tissue growth factor (CCN2) plays a central role in fibrogenesis. Exosomal miR-214-3p can regulate the expression of CCN2 through binding to complementary sites in the 3' untranslated region. This study aimed to explore the role of exosomal miR-214-3p in endometriosis fibrosis and the relationship between CCN2 and miR-214-3p in endometriosis fibrosis. Our results demonstrated that miR-214-3p was significantly down-regulated and CCN2 was up-regulated in EMs ectopic lesion and stromal cells compared with EMs eutopic and endometrium of patients without endometriosis. Exosomal miR-214-3p can inhibit fibrosis in EMs through targeting CCN2. The results were explored and verified in vitro and in vivo, respectively. Cell co-culture was used to explore the contributions of exosomes to intercellular information transmission of miR-214-3p. The results showed that exosomes play a pivotal role in the transportation of miR-214-3p between cells. Furthermore, level of exosomal miR-214-3p in endometriosis patients' serum was lower than that in patients without endometriosis. In conclusion, exosomal miR-214-3p can inhibit fibrosis in EMs by targeting CCN2. MiR-214-3p may be considered as a bio-marker and has a potential therapeutic effect in EMs.

MicroRNA‑202 inhibits endometrial stromal cell migration and invasion by suppressing the K‑Ras/Raf1/MEK/ERK signaling pathway

The enhanced migratory ability of endometrial stromal cells (ESCs) is a key factor in the formation of functional endometrium‑like tissues outside the uterine cavity during endometriosis (EMS). Although accumulating evidence has suggested the importance of microRNAs (miRNAs) in the pathogenesis of EMS, the role of particular miRNAs in the invasiveness of ESCs remain poorly understood. In the present study, the function of miRNAs in the invasiveness of ESCs, along with the associated underlying mechanism involved, were investigated. Initially, the expression patterns of miRNAs in the ectopic and eutopic endometrium isolated from patients with EMS were analyzed using microarray. MicroRNA‑202‑5p (miR‑202) was selected for further study due to its previously reported suppressive effects on the invasion in various types of cancers. The expression of miR‑202 and K‑Ras in eutopic and ectopic endometrioma tissues were detected using reverse transcription‑quantitative PCR, immunohistochemistry and western blotting. The migration and invasion ability of ESCs was determined using wound healing and Transwell invasion assays, respectively. Compared with that from healthy individuals, miR‑202 expression was demonstrated to be lower in the eutopic endometrium from patients with EMS, which was even lower in ectopic endometrium. Functional experiments in primary ESCs revealed that enhanced miR‑202 expression suppressed the cell invasion and migration abilities, which was also accompanied with increased E‑cadherin and reduced N‑cadherin expression in ESCs, suggesting its potentially suppressive role in epithelial‑mesenchymal transition. K‑Ras is a well‑known regulator of the ERK signaling pathway that was shown to be directly targeted and negatively regulated by miR‑202. In addition, K‑Ras expression was found to be upregulated in the ectopic endometrium, where it correlated negatively with that of miR‑202. Knocking down K‑Ras expression mimicked the anti‑invasive effects of miR‑202 overexpression on ESCs, whilst K‑Ras overexpression attenuated the inhibitory role of miR‑202 overexpression in ESC invasion. The K‑Ras/Raf1/MEK/ERK signaling pathway was also blocked by miR‑202 overexpression. These findings suggested that miR‑202 inhibited ESC migration and invasion by inhibiting the K‑Ras/Raf1/MEK/ERK signaling pathway, rendering miR‑202 a candidate for being a therapeutic target for EMS.

Evaluating the effect of ovarian stimulation and exogenous progesterone on CD31-positive cell density, VEGF protein, and miR-17-5p expression of endometrium immediately before implantation

BACKGROUND

MicroRNAs (miRNAs) form a special class of RNAs regulating endometrial functions like cell proliferation, differentiation, angiogenesis, and blastocyst implantation. In addition to providing suitable conditions for embryo development, angiogenesis is a prerequisite to natural pregnancy. The family of vascular endothelial growth factor (VEGF) and its receptors are the main physiological and pathological angiogenesis regulators in the endometrium. In the past, research has demonstrated alteration of angiogenesis and subsequent endometrial receptivity in the stimulated and luteal phase support cycles, when compared with natural cycles.

OBJECTIVE

The objective of this study is to investigate the effect of ovarian stimulation and exogenous progesterone on the density of CD31-positive cell (Endothelial cell), VEGF protein, and miR-17-5p expression in the mouse endometrium immediately before implantation.

METHODS

We employed ovarian stimulated and luteal phase support mice models induced by HMG/HCG and progesterone. The endometrial CD31-positive cell density was determined by immunohistochemistry (IHC) staining, the level of VEGF protein by IHC and western blot analysis, and finally the miR-17-5p expression was determined by the real-time PCR method.

RESULTS

The density of endothelial cell, VEGF protein, and miR-17-5p expression increased in all of the experimental mice when compared to the control group, with the maximum increase having been seen in the group that had received progesterone after ovarian stimulation.

CONCLUSION

This research indicates that ovarian stimulation and exogenous progesterone lead to an increase in the number of endothelial cells by upregulating the VEGF protein. Moreover, except for miR-17-5p, other microRNAs and molecules are presumably involved in angiogenic pathways, thereby requiring more studies.

miR-202-3p overexpression attenuates endometriosis-like lesions by modulating YAP-dependent transcription of S100A6 in murine models

AIM

Recent evidence has suggested the important implications of microRNAs (miRNAs) in the processes of proliferation and tissue remodeling in endometriosis (EMS). We therefore aim to determine the role of miR-202-3p in the pathophysiology of EMS and its underlying mechanisms.

METHODS

Experimental endometriosis was induced in ovariectomized mice implanted with a slow-release 17-β estradiol capsule. Eutopic endometrial stromal cells (euESCs) were isolated and assayed for proliferative, invasive and apoptotic properties by EdU staining, Transwell assays, and flow cytometry. The invasive and apoptotic features in the endometrium of mice with EMS in vivo were evaluated by using immunohistochemical staining and TUNEL assays.

RESULTS

miR-202-3p was observed to be downregulated in the endometrial tissues of EMS patients. MiR-202-3p was also found to target YAP1 which resulted in reduced euESC proliferation and invasion and increased apoptosis. YAP1 was able to phosphorylated STAT3 which consequently upregulated S100A6 to promote the proliferative and invasive abilities of euESCs. MiR-202-3p was thereby proposed to act as an inhibitor of proliferation and tissue damage in the in vivo setting of EMS, its effects however, were able to be counteracted byS100A6, which reversed the effects of miR-202-3p on tissue injury and cell proliferation.

CONCLUSION

Our data together evidenced that miR-202-3p targeted YAP1 to reduce STAT3-mediated S100A6 whereby preventing the progression of EMS.

Analysis of Reciprocally Dysregulated miRNAs in Eutopic Endometrium Is a Promising Approach for Low Invasive Diagnostics of Adenomyosis

Endometriosis is a chronic disease characterized by the growth of endometrial tissue outside of the uterine cavity. Endometriosis affects up to 10% of women of reproductive age and has great social impact. The diagnostics of endometriosis are based on clinical appearance, ultrasound, and magnetic resonance imaging (MRI); however, a diagnosis is frequently hampered by the absence of objective criteria. Adenomyosis (AM) is a particular type of endometriosis wherein the spread of the ectopic endometrial gland is limited by the uterine myometrium. Alteration of the microRNA expression profile in the eutopic endometrium can be associated with AM, and may be assayed for diagnostic purposes. In the presented study, we aimed to explore the diagnostic potency of this approach. Eutopic endometrium specimens were collected from patients (n = 33) and healthy women (n = 30). The microRNA expression was profiled to select individual microRNAs with AM-associated expression alterations. A new method of two-tailed RT-qPCR microRNA analysis was applied to assay potential markers. The expression ratios of reciprocally dysregulated microRNAs were calculated, and the diagnostic potency of these parameters was evaluated by receiver operation curve (ROC) analysis. Mir-10b, miR-200c and miR-191 were significantly dysregulated in the eutopic endometrium of AM patients. The expression ratio of reciprocally dysregulated microRNAs allowed us to diagnose AM with a range of sensitivity from 65% to 74%, and of specificity from 72% to 86%. The analysis of microRNAs from the eutopic endometrium might present a promising low-invasive method of AM diagnostics.

Ovarian stimulation and exogenous progesterone affect the endometrial miR-16-5p, VEGF protein expression, and angiogenesis

Angiogenesis, where vascular endothelial growth factor (VEGF) is critically involved, is an important factor in endometrial receptivity. Angio-miRNAs form a special class of microRNAs (miRNAs) that target angiogenic genes and regulate angiogenesis. Various studies have shown that ovarian stimulation and exogenous progesterone affect endometrial vascular density. The present research aimed to assess the impact of HMG/HCG and progesterone on miR-16-5p, VEGF protein expression, and angiogenesis in the mouse endometrium during the preimplantation period. Forty adult female mice were divided into four groups: 1) control, 2) ovarian stimulation (HMG and 48 h after HCG IP), 3) progesterone (progesterone IP for 3 days), 4) ovarian stimulation + progesterone (HMG and 48 h after HCG IP) + (progesterone IP for 3 days) groups.The mice were sacrificed 96 h following HCG administration. miR-16-5p, VEGF protein expression, and CD31-positive cell (Endothelial cell) density were specified.The results showed that endothelial cell density,VEGF protein, and miR-16-5p expression increased in all treatment groups, with the maximum increase belonging to the ovarian stimulation + progesterone group. This study provides evidence that ovarian stimulation and progesterone administration enhance endometrial angiogenesis through VEGF protein upregulation. Furthermore, except for miR-16-5p, other miRNAs and molecules appear to be involved in angiogenic pathways, thereby requiring further studies.

Plasma miRNAs as biomarkers for endometriosis

STUDY QUESTION

Can plasma miRNAs be used for the non-invasive diagnosis of endometriosis in infertile women?

SUMMARY ANSWER

miRNA-based diagnostic models for endometriosis failed the test of independent validation.

WHAT IS KNOWN ALREADY

Circulating miRNAs have been described to be differentially expressed in patients with endometriosis compared with women without endometriosis, suggesting that they could be used for the non-invasive diagnosis of endometriosis. However, these studies have shown limited consistency or conflicting results, and no miRNA-based diagnostic test has been validated in an independent patient cohort.

STUDY DESIGN, SIZE, DURATION

We performed genome-wide miRNA expression profiling by small RNA sequencing to identify a set of plasma miRNAs with discriminative potential between patients with and without endometriosis. Expression of this set of miRNAs was confirmed by RT-qPCR. Diagnostic models were built using multivariate logistic regression with stepwise feature selection. In a final step, the models were tested for validation in an independent patient cohort.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Plasma of all patients was available in the biobank of the Leuven Endometriosis Centre of Excellence. Biomarker discovery and model development were performed in a discovery cohort of 120 patients (controls = 38, endometriosis = 82), and models were tested for validation in an independent cohort of 90 patients (controls = 30, endometriosis = 60). RNA was extracted with the miRNeasy Plasma Kit. Genome-wide miRNA expression analysis was done by small RNA sequencing using the NEBNext small RNA library prep kit and the NextSeq 500 System. cDNA synthesis and qPCR were performed using the Qiagen miScript technology.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified a set of 42 miRNAs with discriminative power between patients with and without endometriosis based on genome-wide miRNA expression profiling. Expression of 41 miRNAs was confirmed by RT-qPCR, and 3 diagnostic models were built. Only the model for minimal-mild endometriosis (Model 2: hsa-miR-125b-5p, hsa-miR-28-5p and hsa-miR-29a-3p) had diagnostic power above chance performance in the independent validation (AUC = 60%) with an acceptable sensitivity (78%) but poor specificity (37%).

LIMITATIONS, REASONS FOR CAUTION

The diagnostic models were built and tested for validation in two patient cohorts from a single tertiary endometriosis centre. Further validation tests in large cohorts with patients from multiple endometriosis centres are needed.

WIDER IMPLICATION OF THE FINDINGS

Our study supports a possible biological link between certain miRNAs and endometriosis, but the potential of these miRNAs as clinically useful biomarkers is questionable in women with infertility. Large studies in well-described patient cohorts, with rigorous methodology for miRNA expression analysis, sufficient statistical power and an independent validation step, are necessary to answer the question of whether miRNAs can be used as diagnostics markers for endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

The project was funded by a grant from the Research Foundation - Flanders (FWO). A.V., D.F.O. and D.P. are PhD fellows from the FWO. T.D. is vice president and Head of Global Medical Affairs Fertility, Research and Development, Merck KGaA, Darmstadt, Germany. He is also a professor in Reproductive Medicine and Biology at the Department of Development and Regeneration, Group Biomedical Sciences, KU Leuven (University of Leuven), Belgium and an adjunct professor at the Department of Obstetrics and Gynecology in the University of Yale, New Haven, USA. Neither his corporate role nor his academic roles represent a conflict of interest with respect to the work done by him for this study. The other co-authors have no conflict of interest.

TRIAL REGISTRATION NUMBER

Not applicable.

Integrated Bioinformatics Analysis Reveals Function and Regulatory Network of miR-200b-3p in Endometriosis

Objective

MicroRNAs play vital roles in the development of endometriosis. It is reported that miR-200b-3p is downregulated in endometriosis, although its mechanisms in this disease remain still unclear. Therefore, the purpose of this study was to explore the function and potential regulatory network of miR-200b-3p in endometriosis through database analysis.

Methods

The endometriosis gene expression profiles were downloaded from the GEO database to screen differentially expressed genes (DEGs). The predicted and validated target genes of miR-200b-3p were obtained from miRWalk and miRTarBase database. Then, a comparison was performed between miR-200b-3p target genes and DEGs. GO enrichment and KEGG pathway analysis of the target genes was performed using clusterProfiler package. STRING was used to predict the protein-protein interaction among the proteins encoded by the target genes. Then, TransmiR, LncBase, StarBase, PROMO, and AnimalTFDB were employed to identify interactive transcription factors and lncRNAs of miR-200b-3p.

Results

miR-200b-3p was associated with the transcription factors DNMT1, EZH2, HNF1B, JUN, MYB, ZEB1, and ZEB2 during the pathogenesis of endometriosis. The downstream 110 target genes were involved in the biological processes of positive regulation of MAPK cascade, muscle cell proliferation, organ growth, vasculogenesis, and axon development. KEGG analysis revealed that the main pathways related to miR-200b-3p were microRNAs in cancer, PI3K-Akt signaling pathway, colorectal cancer, and tight junction. In addition, four lncRNAs such as MALAT1, NEAT1, SNHG22, and XIST interacted with miR-200b-3p and were associated with transcription factors FOXP3 and YY1.

Conclusion

The predicted target genes and molecular regulatory network of miR-200b-3p in endometriosis not only revealed its biological function but also provided a valuable guideline for further research.

Exosomes: Emerging biomarkers and targets in folliculogenesis and endometriosis

An appropriate connection of the cells in the ovary follicles is vital for a healthy ovule maturation and fertilization, and also for endometrium preparation for implantation that can cause endometriosis. Cellular communication within the follicle and endometrial epithelium involve many signaling molecules. Recent studies indicate that cellular communication can be enclosed by secretion and absorption of small membrane carriers which are named extracellular vesicles including exosomes and microvesicles. Understanding and defining these EVs (Extracellular vesicles) population are important for future studies and clinical translation. Here, we describe the various important cargos which are carried by exosomes during folliculogenesis and endometriosis. Additionally, the current knowledge of exosomes and their cargo within the FF (Follicular fluid) during the folliculogenesis and also in the intrauterine cavity which are involved in endometriosis lesions have also been summarized. Considering the potential importance of this form of the cell to cell communication in the reproductive system, the vital issues under discussion lead to a new insight in this rapidly expanding field and it may be an interesting approach for diagnostic, prognostic and especially therapeutic strategies in the field of infertility and assisted reproductive technology (ART).

MicroRNAs in endometriosis: biological function and emerging biomarker candidates†

MicroRNAs (miRNAs), a class of small noncoding RNA molecules, have been recognized as key post-transcriptional regulators associated with a multitude of human diseases. Global expression profiling studies have uncovered hundreds of miRNAs that are dysregulated in several diseases, and yielded many candidate biomarkers. This review will focus on miRNAs in endometriosis, a common chronic disease affecting nearly 10% of reproductive-aged women, which can cause pelvic pain, infertility, and a myriad of other symptoms. Endometriosis has delayed time to diagnosis when compared to other chronic diseases, as there is no current accurate, easily accessible, and noninvasive tool for diagnosis. Specific miRNAs have been identified as potential biomarkers for this disease in multiple studies. These and other miRNAs have been linked to target genes and functional pathways in disease-specific pathophysiology. Highlighting investigations into the roles of tissue and circulating miRNAs in endometriosis, published through June 2018, this review summarizes new connections between miRNA expression and the pathophysiology of endometriosis, including impacts on fertility. Future applications of miRNA biomarkers for precision medicine in diagnosing and managing endometriosis treatment are also discussed.

MicroRNA22-5p targets ten-eleven translocation and regulates estrogen receptor 2 expression in infertile women with minimal/mild endometriosis during implantation window

Based on microRNA (miR) microarray analysis, we previously found that miR22-5p expression is decreased in the mid-luteal endometrium of women with minimal/mild endometriosis. Bioinformatics analysis predicted that miR22-5p targets ten-eleven translocation (TET2) 3'-untranslated region. This study aimed to determine the regulation and roles of miR22-5p in the pathogenesis of minimal/mild endometriosis-associated infertility. MiR22-5p and TET2 expression in the mid-luteal endometrium from women with or without minimal/mild endometriosis was analyzed. After transfection with miR22-5p mimics or inhibitor, TET2 expression was analyzed by quantitative reverse transcription (RT-q) PCR, western blotting and immunohistochemistry. 5-Hydroxymethylcytosine was determined by immunofluorescence and dot blotting. Expression and promoter methylation of estrogen receptor 2 (ESR2) was measured by RT-qPCR and western blotting, and by bisulfite sequencing, respectively. We first established that miR22-5p expression decreased and TET2 expression increased in minimal/mild endometriosis during implantation window. TET2 was found to be a direct target of miR22-5p. MiR22-5p regulated the expression of ESR2, but did not directly affect methylation of its promoter region (-197/+359). Our results suggest that an imbalance in miR22-5p expression in the mid-luteal endometrium may be involved in minimal/mild endometriosis-associated infertility.

Molecular signature of eutopic endometrium in endometriosis based on the multi-omics integrative synthesis

PURPOSE

To synthesise data from genome-wide studies reporting molecular signature of eutopic endometrium through the phases of the menstrual cycle in endometriosis.

METHODS

Extraction of data from publications reporting genetic signatures characterising endometrium associated with endometriosis. The nomenclature of extracted differentially expressed transcripts and proteins was adopted according to the HUGO Gene Nomenclature Committee (HGNC). Loci were further sorted according to the different phases of the menstrual cycle, i.e. menstrual (M), proliferative (P), secretory (S), early-secretory (ES), mid-secretory (MS), late-secretory (LS), and not specified (N/S) if the endometrial dating was not available. Enrichment analysis was performed using the DAVID bioinformatics tool.

RESULTS

Altered molecular changes were reported by 21 studies, including 13 performed at the transcriptomic, 6 at proteomic, and 2 at epigenomic level. Extracted data resulted in a catalogue of total 670 genetic causes with available 591 official gene symbols, i.e. M = 3, P = 188, S = 81, ES = 82, MS = 173, LS = 36, and N/S = 28. Enriched pathways included oestrogen signalling pathway, extracellular matrix organization, and endothelial cell chemotaxis. Our study revealed that knowledge of endometrium biology in endometriosis is fragmented due to heterogeneity of published data. However, 15 genes reported as dysregulated by at least two studies within the same phase and 33 significantly enriched GO-BP terms/KEGG pathways associated with different phases of the menstrual cycle were identified.

CONCLUSIONS

A multi-omics insight into molecular patterns underlying endometriosis could contribute towards identification of endometrial pathological mechanisms that impact fertility capacities of women with endometriosis.

Genome-wide profiling of miRNA expression patterns in tubal endometriosis

MicroRNA (miRNA) expression profiles in tubal endometriosis (EM) are still poorly understood. In this study, we analyzed the differential expression of miRNAs and the related gene networks and signaling pathways in tubal EM. Four tubal epithelium samples from tubal EM patients and five normal tubal epithelium samples from uterine leiomyoma patients were collected for miRNA microarray. Bioinformatics analyses, including Ingenuity Pathway Analysis (IPA), Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, were performed. Quantitative real-time polymerase chain reaction (qRT-PCR) validation of five miRNAs was performed in six tubal epithelium samples from tubal EM and six from control. A total of 17 significantly differentially expressed miRNAs and 4343 potential miRNA-target genes involved in tubal EM were identified (fold change >1.5 and FDR-adjusted P value <0.05). IPA indicated connections between miRNAs, target genes and other gynecological diseases like endometrial carcinoma. GO and KEGG analysis revealed that most of the identified genes were involved in the mTOR signaling pathway, SNARE interactions in vesicular transport and endocytosis. We constructed an miRNA-gene-disease network using target gene prediction. Functional analysis showed that the mTOR pathway was connected closely to tubal EM. Our results demonstrate for the first time the differentially expressed miRNAs and the related signal pathways involved in the pathogenesis of tubal EM which contribute to elucidating the pathogenic mechanism of tubal EM-related infertility.

Endometriosis research in the -omics era

Endometriosis is a pathological condition extensively studied, but its pathogenesis is not completely understood, since its pathophysiology stems from a broad spectrum of environmental influences and genetic factors. Moreover, the nature of this condition is heterogeneous and includes different anatomical entities. Scientists actively pursue discovery of novel biomarkers in the hope of better identifying susceptible individuals in early stages of the disease. High-throughput technologies have substantially revolutionized medical research and, as a first step, the advent of genotyping arrays led to large-scale genome-wide association studies (GWAS) and enabled the assessment of global transcript levels, thus giving rise to integrative genetics. In this framework, comprehensive studies have been conducted at multiple biological levels by using the "omics" platforms, thus allowing to re-examine endometriosis at a greater degree of molecular resolution. -Omics technologies can detect and analyze hundreds of markers in the same experiment and their increasing use in the field of gynecology comes from an urgent need to find new diagnostic and therapeutic tools that improve the diagnosis of endometriosis and the efficacy of assisted reproductive techniques. Proteomics and metabolomics have been introduced recently into the every day methodology of researchers collaborating with gynecologists and, importantly, multi-omics approach is advantageous to gain insight of the total information that underlies endometriosis, compared to studies of any single -omics type. In this review, we expect to present multiple studies based on the high-throughput-omics technologies and to shed light in all considerable advantages that they may confer to a proper management of endometriosis.

Association of miR-27aA>G, miR-423C>a, miR-449bA>G, and miR-604A>G Polymorphisms with Risk of Recurrent Implantation Failure

Recurrent implantation failure (RIF) is defined when pregnancy failure occurs after two consecutive in vitro fertilization-embryo transfers to the endometrium using at least four high-quality embryos in women. MicroRNAs are well-known function modulators and are involved in many diseases. Recently, studies on microRNA and recurrent pregnancy loss (RPL) have been actively carried out; however, single nucleotide polymorphisms of miRNA in RPL are not well known. Therefore, we set the aim of this study to identify whether polymorphisms in miRNAs that miR-27aA>G, miR-423C>A, miR-449bA>G, and miR-604A>G are risk factors for idiopathic recurrent implantation failure (RIF) in Korean women. Genotyping was assessed with a polymerase chain reaction-restriction fragment length polymorphism assay. We examined polymorphisms in four miRNA genes: miR-27aA>G, miR-423C>A, miR-449bA>G, and miR-604A>G. We found that the miR-27aA>G, miR-449bA>G, and miR-604A>G polymorphisms were significantly associated with a risk of RIF. In addition, the miR-27aA>G and miR-449bA>G polymorphisms were associated with the frequency of implantation failures. Specifically, the miR-449bAG+GG genotype was associated with RIF prevalence (total RIF: adjusted odd ratio [AOR] = 1.584, 95% CI = 1.008-2.490, P = 0.046; IF ≥ 3 group: AOR = 1.747, 95% CI = 1.088-2.803, P = 0.021; IF ≥ 4: AOR = 1.932, 95% CI = 1.122-3.327, P = 0.018). Based on these results, the miR-449b A>G may be a predisposing factor to RIF susceptibility. However, the mechanism underlying the function of miR-449b A>G in RIF remains to be determined and further studies are needed to improve understanding of the roles of miR-449b A>G, using a larger and more heterogeneous cohort.

Knockdown of circ-ABCB10 promotes sensitivity of lung cancer cells to cisplatin via miR-556-3p/AK4 axis

BACKGROUND

Due to the acquired drug resistance, the potency of cisplatin-based chemotherapy is limited in lung cancer, which is a big obstacle in clinical treatment of lung cancer. Abundant evidence has revealed that circular RNAs (circRNAs) exerted facilitating or suppressive function on the tumorigenesis of multiple cancers. The oncogenic role of circ-ABCB10 in breast cancer and clear cell renal cell carcinoma has been validated in recent researches. However, the regulatory mechanism of circ-ABCB10 and its relation to cellular sensitivity to cisplatin in lung cancer is poorly understood.

METHODS

The expression and characteristic of circ-ABCB10 were analyzed by RT-qPCR and nucleic acid electrophoresis. CCK-8, colony formation, TUNEL and transwell assays were applied to probe the role of FOXD3-AS1 in lung cancer. The interactions of miR-556-3p with circ-ABCB10 and AK4 were testified by luciferase reporter and RIP assays.

RESULTS

Circ-ABCB10 was markedly upregulated and featured with loop structure in lung cancer. Circ-ABCB10 depletion suppresses lung cancer progression and sensitizes lung cancer cells to cisplatin. Molecular mechanism assays manifested that circ-ABCB10 bound with miR-556-3p and negatively modulated miR-556-3p expression. Additionally, AK4 was testified to be the downstream target of miR-556-3p. More importantly, rescue assays clarified that upregulation of AK4 could reverse the cisplatin-sensitizing and tumor-suppressing effect of circ-ABCB10 knockdown on lung cancer cells.

CONCLUSIONS

Circ-ABCB10 knockdown enhances sensitivity of lung cancer cells to cisplatin by targeting miR-556-3p/AK4 axis.

Dysregulation of miR-202-3p Affects Migration and Invasion of Endometrial Stromal Cells in Endometriosis via Targeting ROCK1

Dysregulation of microRNAs in endometrial cells plays a pivotal role in the pathogenesis of endometriosis (EM). This study aims to investigate the implication of aberrant miR-202-3p expression in EM and the underlying mechanisms. We demonstrated that miR-202-3p was significantly downregulated in eutopic endometrium of EM in comparison to normal endometrial samples (P < 0.05). Primary endometrial stromal cells (ESCs) isolated from eutopic or ectopic endometrium also showed a significant decrease in miR-202-3p level compared to ESCs from normal endometrium (P < 0.01). Functional studies using MTT, wound healing assay and transwell assay indicated that overexpression of miR-202-3p greatly impaired cell viability, migration, and invasion, whereas suppression of miR-202-3p exhibited the opposite effects (P < 0.05 or P < 0.01). miR-202-3p mimics or inhibitors transfection significantly decreased or increased expression of Rho-associated, coiled-coil containing protein kinase 1 (ROCK1), respectively, in ESCs (P < 0.01). Using dual luciferase reporter assay, we validated ROCK1 as a direct target of miR-202-3p. Moreover, negative correlations between miR-202-3p and ROCK1 mRNA/protein levels were determined in both eutopic and normal control endometrium (P < 0.01). In conclusion, these findings suggest that suppression of miR-202-3p in ESCs results in enhanced cell viability, invasion, and migration at least partially via upregulation of its target ROCK1, which eventually contributes to the development of endometriosis.

microRNA-141 inhibits TGF-β1-induced epithelial-to-mesenchymal transition through inhibition of the TGF-β1/SMAD2 signalling pathway in endometriosis

PURPOSE

Recent studies have demonstrated the differential expression of micro(mi)RNAs in endometriosis. Previously, we reported the low expression of miR-141 in patients with this disease. Epithelial-to-mesenchymal transition (EMT) and the transforming growth factor-beta1 (TGF-β1)-induced SMAD2 signalling pathway are central to tumour proliferation and invasion. However, the role of miR-141 in regulating the TGF-β1/SMAD2 signalling pathway and the associated EMT to be elucidated.

METHODS

The levels of TGF-β1/SMAD2 signalling and EMT markers expression in eutopic and ectopic endometria of endometriosis were determined by immunohistochemistry and western blot analyses. MiR-141 expression was analysed by quantitative reverse-transcription polymerase chain reaction. Cellular invasion and proliferation were determined by transwell and CCK-8 assays, respectively. Functional assay of miR-141 was performed using plasmid and shRNA transfection methods.

RESULT

The presence of miR-141, EMT, and TGF-β1/SMAD2 signalling markers were detected in eutopic and ectopic endometria of endometriosis. TGF-β1-induced EMT in Ishikawa (ISK) cells by activating the SMAD2 signalling pathway, whereas miR-141 inhibited the TGF-β1-induced EMT, proliferation and invasion abilities of these cells.

CONCLUSION

These data identify miR-141 as a novel driver of EMT in endometriosis, implicates the link between miR-141 and TGF-β1/SMAD2 signalling pathway in the context of endometriosis, and underscore the role of EMT in the development of endometriosis.