MicroRNA 135 regulates HOXA10 expression in endometriosis

Single-cell transcriptomic analysis of immune cell dynamics in the healthy human endometrium

The microenvironment of the endometrial immune system is crucial to the success of placental implantation and healthy pregnancy. However, the functionalities of immune cells across various stages of the reproductive cycle have yet to be fully comprehended. To address this, we conducted advanced bioinformatic analysis on 230,049 high-quality single-cell transcriptomes from healthy endometrial samples obtained during the proliferative, secretory, early pregnancy, and late pregnancy stages. Our investigation has unveiled that proliferative natural killer (NK) cells, a potential source of endometrial NK cells, exhibit the most robust proliferative and differentiation potential during non-pregnant stages. We have also identified similar differentiation trajectories of NK cells originating from proliferative NK cells across four stages. Notably, during early pregnancy, NK cells demonstrate the highest oxidative phosphorylation metabolism activity, and, in conjunction with macrophages and T cells, exhibit the strongest type II interferon response. With spatial transcriptome data, we have discerned that the most robust immune-non-immune interactions are associated with the promotion and inhibition of cell proliferation, differentiation and migration during four stages. Furthermore, we have compiled lists of stage-specific risk genes implicated in reproductive diseases, which hold promise as potential disease biomarkers. Our study provides insights into the dynamics of the endometrial immune microenvironment during different reproductive cycle stages, thus serving as a reference for detecting pathological changes during pregnancy.

Uterine fluid microRNAs in repeated implantation failure

Recurrent implantation failure (RIF) is a significant obstacle in assisted reproductive procedures, primarily because of compromised receptivity. As such, there is a need for a dependable and accurate clinical test to evaluate endometrial receptiveness, particularly during embryo transfer. MicroRNAs (miRNAs) have diverse functions in the processes of implantation and pregnancy. Dysregulation of miRNAs results in reproductive diseases such as recurrent implantation failure (RIF). The endometrium secretes several microRNAs (miRNAs) during the implantation period, which could potentially indicate whether the endometrium is suitable for in vitro fertilization (IVF). The goal of this review is to examine endometrial miRNAs as noninvasive biomarkers that successfully predict endometrium receptivity in RIF.

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.

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.

Expression of HOXA10 Gene in Women with Endometriosis: A Systematic Review

The homeobox A10 (HOXA10) gene is known to be related to endometriosis; however, due to a lack of knowledge/evidence in the pathogenesis of endometriosis, the mechanisms that link HOXA10 to endometriosis still need to be clarified. This review addresses the difference in the expression of the HOXA10 gene in endometriotic women versus non-endometriotic women across populations by country and discusses its influences on women's fertility. An organized search of electronic databases was conducted in Scopus, ScienceDirect, PubMed, and Web of Science. The keywords used were (HOXA10 OR "homeobox A10" OR PL OR HOX1 OR HOX1H OR HOX1.8) AND ("gene expression") AND (endometriosis). The initial search resulted in 623 articles, 10 of which were included in this review. All ten papers included in this study were rated fair in terms of the quality of the studies conducted. The expression of the HOXA10 gene was found to be downregulated in most studies. However, one study provided evidence of the downregulation and upregulation of HOXA10 gene expression due to the localization of endometriotic lesions. Measuring the expression of the HOXA10 gene in women is clinically essential to predicting endometriosis, endometrial receptivity, and the development of pinopodes in the endometrium during the luteal phase.

Towards a Better Understanding of Endometriosis-Related Infertility: A Review on How Endometriosis Affects Endometrial Receptivity

Endometriosis is the most common cause of infertility. Endometrial receptivity has been suggested to contribute to infertility and poor reproductive outcomes in affected women. Even though experimental and clinical data suggest that the endometrium differs in women with endometriosis, the pathogenesis of impaired endometrial receptivity remains incomplete. Therefore, this review summarizes the potential mechanisms that affect endometrial function and contribute to implantation failure. Contemporary data regarding hormone imbalance, inflammation, and immunoregulatory dysfunction will be reviewed here. In addition, genetic, epigenetic, glycosylation, metabolism and microRNA in endometriosis-related infertility/subfertility will be summarized. We provide a brief discussion and perspectives on their future clinical implications in the diagnosis and therapy to improve endometrial function in affected women.

The role of miRNAs and lncRNAs in neurofibromatosis type 1

Neurofibromatosis Type 1 (NF1) is a frequent cancer predisposition syndrome. The common hallmark of patients with this multisystemic genetic disorder is the formation of peripheral nerve sheath tumors, which can be seen as either dermal, plexiform, and malignant forms. MicroRNA (miRNA) is an essential gene regulation factor and consists of 22-25 nucleotides. MiRNAs are identified to act as both tumor suppressors and oncogenes (oncomirs) in a wide variety of human cancers. They play multiple roles in molecular pathways responsible for tumor homing, progression, and invasion. Long noncoding RNA (lncRNA) also has a key role in cancer transcriptomics. Altered lncRNA expression levels have been found in various malignancies. This review aims to summarize the role of two noncoding RNA groups, miRNAs and lncRNAs, in NF1 establishment, development, and progression. We also highlight their potential for future clinical interventions and devising new diagnostic tools.

FHL1 mediates HOXA10 deacetylation via SIRT2 to enhance blastocyst-epithelial adhesion

Recurrent implantation failure (RIF) is a rather thorny problem in the clinical practice of assisted reproductive technology. Due to the complex aetiology of RIF, its pathogenesis is far from fully understood, and there is no effective treatment available. Here, We explored the regulatory mechanism of the four half-domains of LIM domain 1 (FHL1), which is significantly downregulated in the endometrium of RIF patients, in blastocyst-epithelial adhesion. Indeed, FHL1 expression was dramatically increased in normal female mid-secretory endometrial epithelial cells and was abnormally reduced in RIF patients. Furthermore, FHL1 overexpression promoted blastocyst-epithelial adhesion, and interfering with FHL1 expression in the mouse uterus significantly inhibited embryo implantation. Mechanistically, FHL1 did not regulate HOXA10 mRNA expression but increased HOXA10 protein stability and activated HOXA10, thereby promoting its regulation of downstream gene expression and the β3 integrin/FAK pathway. Meanwhile, FHL1 regulates HOXA10 function by increasing HOXA10 deacetylation through enhanced binding of HOXA10 and SIRT2. SIRT2-specific inhibitors can significantly inhibit this effect. In the endometrial epithelial cells of RIF patients, the correlation between FHL1 and HOXA10 and its downstream target genes has also been verified. Finally, our data indicated FHL1 is a regulatory molecule that promotes blastocyst-epithelial adhesion. Altogether, downstream dysfunction due to aberrant FHL1 expression is an important molecular basis for embryo implantation failure in patients with RIF and to provide new potential therapeutic targets.

Endometriosis-associated infertility: From pathophysiology to tailored treatment

Despite the clinically recognized association between endometriosis and infertility, the mechanisms implicated in endometriosis-associated infertility are not fully understood. Endometriosis is a multifactorial and systemic disease that has pleiotropic direct and indirect effects on reproduction. A complex interaction between endometriosis subtype, pain, inflammation, altered pelvic anatomy, adhesions, disrupted ovarian reserve/function, and compromised endometrial receptivity as well as systemic effects of the disease define endometriosis-associated infertility. The population of infertile women with endometriosis is heterogeneous, and diverse patients' phenotypes can be observed in the clinical setting, thus making difficult to establish a precise diagnosis and a single mechanism of endometriosis related infertility. Moreover, clinical management of infertility associated with endometriosis can be challenging due to this heterogeneity. Innovative non-invasive diagnostic tools are on the horizon that may allow us to target the specific dysfunctional alteration in the reproduction process. Currently the treatment should be individualized according to the clinical situation and to the suspected level of impairment. Here we review the etiology of endometriosis related infertility as well as current treatment options, including the roles of surgery and assisted reproductive technologies.

A review on the importance of miRNA-135 in human diseases

MicroRNA-135 (miR-135) is a microRNA which is involved in the pathoetiology of several neoplastic and non-neoplastic conditions. Both tumor suppressor and oncogenic roles have been reported for this miRNA. Studies in prostate, renal, gallbladder and nasopharyngeal cancers as well as glioma have shown down-regulation of miR-135 in cancerous tissues compared with controls. These studies have also shown the impact of miR-135 down-regulation on enhancement of cell proliferation and aggressive behavior. Meanwhile, miR-135 has been shown to be up-regulated in bladder, oral, colorectal and liver cancers. Studies in breast, gastric, lung and pancreatic cancers as well as head and neck squamous cell carcinoma have reported dual roles for miR-135. Dysregulation of miR-135 has also been noted in various non-neoplastic conditions such as Alzheimer’s disease, atherosclerosis, depression, diabetes, Parkinson, pulmonary arterial hypertension, nephrotic syndrome, endometriosis, epilepsy and allergic conditions. In the current review, we summarize the role of miR-135 in the carcinogenesis as well as development of other disorders.

Hsa-mir-135a Shows Potential as A Putative Diagnostic Biomarker in Saliva and Plasma for Endometriosis

Endometriosis is a chronic disease characterized by the implantation and proliferation of endometrial tissue outside of the uterine cavity. The nonspecific nature of the symptoms and the lack of sensitive, noninvasive diagnostic methods often lead to a significant delay in diagnosis, highlighting the need for diagnostic biomarkers. The correlation of circulating miRNAs with altered inflammatory signals seen in patients with endometriosis has raised the possibility that miRNAs can serve as biomarkers for the disease. In our study, we analyzed miRNA expression in saliva of women with and without endometriosis using a FireFly custom multiplex circulating miRNA assay. This focused panel included 28 human miRNAs, 25 of which have been previously found to be differentially expressed either in plasma, serum, and/or blood of women with endometriosis, compared to controls. We found that hsa-mir-135a was expressed significantly higher in the saliva of women with endometriosis, independent of disease stage and menstrual cycle phase. We confirmed that hsa-mir-135a also showed significantly elevated expression in the plasma of endometriosis patients. This indicates that hsa-mir-135a is a putative noninvasive biomarker of endometriosis in both saliva and plasma, but further validation studies are required to assess its clinical value as a biomarker.

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.

MiR-135a-5p suppresses trophoblast proliferative, migratory, invasive, and angiogenic activity in the context of unexplained spontaneous abortion

BACKGROUND

Spontaneous abortions (SA) is amongst the most common complications associated with pregnancy in humans, and the underlying causes cannot be identified in roughly half of SA cases. We found miR-135a-5p to be significantly upregulated in SA-associated villus tissues, yet the function it plays in this context has yet to be clarified. This study explored the function of miR-135a-5p and its potential as a biomarker for unexplained SA.

METHOD

RT-qPCR was employed for appraising miR-135a-5p expression within villus tissues with its clinical diagnostic values being assessed using ROC curves. The effects of miR-135a-5p in HTR-8/SVneo cells were analyzed via wound healing, Transwell, flow cytometry, EdU, CCK-8, and tube formation assays. Moreover, protein expression was examined via Western blotting, and interactions between miR-135a-5p and PTPN1 were explored through RIP-PCR, bioinformatics analyses and luciferase reporter assays.

RESULTS

Relative to normal pregnancy (NP), villus tissue samples from pregnancies that ended in unexplained sporadic miscarriage (USM) or unexplained recurrent SA (URSA) exhibited miR-135a-5p upregulation. When this miRNA was overexpressed in HTR-8/SVneo cells, their migration, proliferation, and cell cycle progression were suppressed, as were their tube forming and invasive activities. miR-135a-5p over-expression also downregulated the protein level of cyclins, PTPN1, MMP2 and MMP9. In RIP-PCR assays, the Ago2 protein exhibited significant miR-135a-5p and PTPN1 mRNA enrichment, and dual-luciferase reporter assays indicated PTPN1 to be a bona fide miR-135a-5p target gene within HTR-8/SVneo cells.

CONCLUSION

miR-135a-5p may suppress trophoblast migratory, invasive, proliferative, and angiogenic activity via targeting PTPN1, and it may thus offer value as a biomarker for unexplained SA.

Methylation of microribonucleic acid Let-7b regulatory regions in endometriosis

OBJECTIVE

To evaluate whether Let-7b regulatory regions are methylated in endometriosis and whether there are specific CpG methylation sites that can be identified as key epigenetic regulatory locations.

DESIGN

Laboratory study.

SETTING

Academic Medical Center.

PATIENT(S)

Twenty-one women with (n = 12) and without (n = 9) endometriosis.

INTERVENTION(S)

Laboratory investigation. In vitro assessment of Let-7b methylation.

MAIN OUTCOME MEASURE(S)

Four targeted regions upstream of Let-7b predicted to be the regulatory regions of this microribonucleic acid (miRNA) were amplified using bisulfite-specific polymerase chain reaction. Deoxyribonucleic acid sequences were analyzed to determine methylation status at each predicted regulatory region and CpG island.

RESULT(S)

Regions were chosen on the basis of percent (%) GC content and data from Ensembl/ENCODE databases, which predict locations of promoters, enhancers, CTCF, and transcription factor binding sites as well as candidate cis-regulatory elements. A region 1,161 base pairs upstream of the Let-7b coding region was significantly differentially methylated in ectopic samples compared with eutopic endometrium from patients with endometriosis. Four specific CpG islands within this region 2 were further analyzed individually, and 1 was found to be significantly methylated in endometriosis. We identified that transcription factor SP1 was predicted to bind to a sequence that contained this specific methylated CpG in endometriosis.

CONCLUSION(S)

We identified differential Let-7b methylation in endometriosis, demonstrating that the epigenetic nature of the disease extends to the regulation of miRNAs. Methylation of this novel Let-7b regulatory region explains the decreased levels of this miRNA in endometriosis and is distinct from the regions implicated in regulating Let-7b in cancer. Understanding of the disease-specific mechanisms leading to diminished expression may allow for better understanding of the etiology of endometriosis as well as development of new treatment options.

Anti-miR-135/SPOCK1 axis antagonizes the influence of metabolism on drug response in intestinal/colon tumour organoids

Little is known about the role of microRNAs (miRNAs) in rewiring the metabolism within tumours and adjacent non-tumour bearing normal tissue and their potential in cancer therapy. This study aimed to investigate the relationship between deregulated miRNAs and metabolic components in murine duodenal polyps and non-polyp-derived organoids (mPOs and mNPOs) from a double-mutant Apc^MinFbxw7^∆G mouse model of intestinal/colorectal cancer (CRC). We analysed the expression of 373 miRNAs and 12 deregulated metabolic genes in mPOs and mNPOs. Our findings revealed miR-135b might target Spock1. Upregulation of SPOCK1 correlated with advanced stages of CRCs. Knockdown of miR-135b decreased the expression level of SPOCK1, glucose consumption and lactic secretion in CRC patient-derived tumours organoids (CRC tPDOs). Increased SPOCK1 induced by miR-135b overexpression promoted the Warburg effect and consequently antitumour effect of 5-fluorouracil. Thus, combination with miR-135b antisense nucleotides may represent a novel strategy to sensitise CRC to the chemo-reagent based treatment.

Overexpression of HOXA10 promotes the growth and metastasis of nasopharyngeal carcinoma

Deregulation of HOX transcription factor family has frequently been observed in multiple human cancers; however, their role in nasopharyngeal carcinoma remains largely unclear. In the present study, we found that HOX gene family is consistently upregulated in nasopharyngeal carcinoma and identified HOXA10 as one of the mostly upregulated HOX genes. Importantly, we show that HOXA10 overexpression is associated with transcriptional activation of multiple oncogenes essential for nasopharyngeal carcinoma carcinogenesis, including S-phase kinase-associated protein 2 (SKP2), calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2), and matrix metalloproteinase 1 (MMP1). Mechanistically, the overexpression of SKP2 induces the degradation of cell cycle inhibitor p27, leading to rapid cell cycle progression and cell proliferation. The overexpression of CAMKK2 is associated with enhanced mTOR signaling activity to meet the increased demand for proteins synthesis in rapid growing nasopharyngeal carcinoma cells. Moreover, MMP1 overexpression facilitates nasopharyngeal carcinoma cell migration and invasion and contributes to cancer metastasis and progression. We thus concluded that HOXA10 overexpression promotes the growth and metastasis of nasopharyngeal carcinoma by transcriptionally activating various oncogenic pathways.

The role of epigenetic mechanisms in the regulation of gene expression in the cyclical endometrium

BACKGROUND

The human endometrium is a highly dynamic tissue whose function is mainly regulated by the ovarian steroid hormones estradiol and progesterone. The serum levels of these and other hormones are associated with three specific phases that compose the endometrial cycle: menstrual, proliferative, and secretory. Throughout this cycle, the endometrium exhibits different transcriptional networks according to the genes expressed in each phase. Epigenetic mechanisms are crucial in the fine-tuning of gene expression to generate such transcriptional networks. The present review aims to provide an overview of current research focused on the epigenetic mechanisms that regulate gene expression in the cyclical endometrium and discuss the technical and clinical perspectives regarding this topic.

MAIN BODY

The main epigenetic mechanisms reported are DNA methylation, histone post-translational modifications, and non-coding RNAs. These epigenetic mechanisms induce the expression of genes associated with transcriptional regulation, endometrial epithelial growth, angiogenesis, and stromal cell proliferation during the proliferative phase. During the secretory phase, epigenetic mechanisms promote the expression of genes associated with hormone response, insulin signaling, decidualization, and embryo implantation. Furthermore, the global content of specific epigenetic modifications and the gene expression of non-coding RNAs and epigenetic modifiers vary according to the menstrual cycle phase. In vitro and cell type-specific studies have demonstrated that epithelial and stromal cells undergo particular epigenetic changes that modulate their transcriptional networks to accomplish their function during decidualization and implantation.

CONCLUSION AND PERSPECTIVES

Epigenetic mechanisms are emerging as key players in regulating transcriptional networks associated with key processes and functions of the cyclical endometrium. Further studies using next-generation sequencing and single-cell technology are warranted to explore the role of other epigenetic mechanisms in each cell type that composes the endometrium throughout the menstrual cycle. The application of this knowledge will definitively provide essential information to understand the pathological mechanisms of endometrial diseases, such as endometriosis and endometrial cancer, and to identify potential therapeutic targets and improve women's health.

Endometriosis, infertility and MicroRNA's: A review

The review aims to explore circulating small non- coding regulatory Ribonucleic Acids (miRNA) as biomarkers of endometriosis; a reproductive age group disorder. miRNA are linked with genetic, epigenetic and angiogenic factors, hormones, cytokines, chemokines, oxidative stress (OS) markers, mediators of inflammation, hypoxia, angiogenesis and altered immune system contributing to the pathogenesis of endometriosis. Hormonal imbalance occurs by decreased levels of miRNAs -23a and miRNAs -23b and increase in miRNAs -:135a, 135b, 29c and 194-3p. Angiogenesis by vascular endothelial growth factor is attributed to increased miRNAs -126, miRNAs -210, miRNAs -21, miRNAs -199a-5p and miRNAs 20A. OS upregulates miRNAs -302a by increased levels of Tumor Necrosis factor (TNF)-α, TNF- β and Interleukin -1β. Upregulation of miRNAs -199a and miRNAs -16 promotes inflammation and cell proliferation in the endometriotic lesions. The gold standard to diagnose endometriosis is laparoscopy, yet miRNA can be validated as diagnostic tool for detection, progression and prevention of endometriosis in large, independent cohorts of women, with and without endometriosis.

Binding of microRNA-135a (miR-135a) to homeobox protein A10 (HOXA10) mRNA in a high-progesterone environment modulates the embryonic implantation factors beta3-integrin (ITGβ3) and empty spiracles homeobox-2 (EMX2)

Background

Patients with elevated circulating progesterone concentrations on the day of the human chorionic gonadotropin (hCG) trigger had relatively low implantation rates during assisted reproductive treatments. In this study, we assess the hypothesis that different concentrations of progesterone regulate the expression of homeobox protein A10 (HOXA10) and its downstream genes through miRNA-135a.

Methods

MicroRNA-135a (miR-135a), HOXA10, beta3-integrin (ITGβ3), and empty spiracles homeobox-2 (EMX2) expression levels in endometrial tissues from patients with elevated progesterone were measured. To determine the threshold of progesterone level which can impair implantation, Ishikawa cells were used to determine the expression of the aforementioned 4 genes after exposure to 5 graded concentrations of progesterone. The dual-luciferase reporter assay was used to verify whether miR-135a regulated the expression of HOXA10. Furthermore, the effects of HOXA10 on the expression of key endometrial receptivity genes ITGβ3 and EMX2 were confirmed.

Results

High progesterone levels promoted miR-135a expression in vivo, and miR-135a bound to the 3'-untranslated region (3'-UTR) of HOXA10 mRNA to inhibit HOXA10 expression. Reduction of HOXA10 promoted EMX2 expression and inhibited ITG-3 production. Progesterone promoted the expression of HOXA10 in vitro at low concentrations. However, when the concentration was greater than 10⁻⁷ ng/mL, progesterone inhibited HOXA10 by promoting miR-135a expression, thereby altering the expression of related genes and affecting endometrial receptivity.

Conclusions

In vitro, the trend in miR-135a expression (which first decreased and then increased) was in direct contrast to that of HOXA10 expression (which first increased and then decreased) as progesterone levels increased. The key factors regulating endometrial receptivity included ITGβ3 and EMX2, which were confirmed to be regulated by HOXA10. High progesterone levels affected miR-135a expression, and miR-135a inhibited HOXA10 expression, thereby affecting endometrial receptivity.

Lnc-RNA LINC01279 induces endometriosis via targeting of HOXA10

AIM

To explore the regulatory role and molecular mechanism of lncRNA-LINC01279 in endometriosis (EMs).

METHODS

Between September 2018 and July 2019, 20 EMs patients and 20 healthy subjects were recruited to detect the expression of lncRNA-LINC01279 in EMs and in normal endometrium via qRT-PCR. Autograft was used to establish EMs models on Spraque-Dawley (SD) rats, which was followed by taking volume measurements of EMs endometrium and observing pathological changes in the morphology of EMs via hematoxylin and eosin (H&E) staining. The qRT-PCR technique was further carried out to determine mRNA expression of lncRNA-LINC01279 and HOXA10 in the serum of EMs rats and LINC01279 shRNA-transfected rats, while the protein expression of HOXA10 was determined using a Western blot.

RESULTS

EMs patients presented with upregulation of lncRNA-LINC01279 and downregulation of HOXA10 (p < 0.01 or 0.001). Online predictions further revealed that lncRNA-LINC01279 regulated the expression of HOXA10 via miRNA-135b. In EMs models, it was observed that there were a significantly enlarged endometrium and poor pathological morphology, significant upregulation of lncRNA-LINC01279, and downregulation of miR-135b and HOXA10 in serum (p < 0.05, 0.01 or 0.001). In the lncRNA-LINC01279 shRNA group, EMs rats, following treatment, had a sharp decrease in the volume of EMs endometrium, and an improvement in pathological morphology, while lncRNA-LINC01279 was downregulated, with upregulation of miR-135b and HOXA10 (p < 0.05, 0.01 or 0.001).

CONCLUSION

LncRNA-LINC01279, by the mechanism of targeting miR-135b, has the potential to downregulate the expression of HOXA10, and therefore, can promote the development and progression of EMs.

Association of miRNA-145 with the occurrence and prognosis of hydrosalpinx-induced defective endometrial receptivity

MiR-145 is reported to facilitate inflammation and is also associated with unsuccessful embryonic implantation. Whether miR-145 mediates inflammatory response underlying hydrosalpinx-induced defective endometrial receptivity (ER) remains unclear, and this study attempted to clarify this point. Endometrium samples were collected from hydrosalpinx patients (case, n = 243) and patients with tubal patency/obstruction (control, n = 187). The peripheral blood samples of cases and controls were collected to determine the genotypes of miR-145 SNPs. The value of miR-145 expression in the diagnosis and prognostic estimation of hydrosalpinx was assessed using ROC curve and regression analysis, respectively. Lipopolysaccharide (LPS) cell model was established with endometrial cells, and cells were transfected with miR-145 mimic, inhibitor, or negative control. MiR-145 and cytokine levels were quantified by quantitative reverse transcription PCR or western blot. MiR-145 expression was significantly higher in hydrosalpinx compared to control group, and high miR-145 expression was significantly associated with moderate/severe tube lesion, high pulsatility index (>1.06), and high resistance index (>0.61) in hydrosalpinx patients. ROC curve analysis indicated that monitoring miR-145 expression may be useful for the diagnosis of hydrosalpinx (AUC = 0.704). A alleles of rs41291957 (G>A) and rs353292 (G>A) were significantly associated with an increased risk of hydrosalpinx compared to G allele (p < 0.05), yet the mutant allele of rs353291 (A>G) and rs4705343 (T>C) significantly reduced susceptibility to hydrosalpinx compared to the wild type allele. Treatments with miR-145 mimic and LPS in endometrial cells significantly increased the levels of transforming growth factor-β1, tumor necrosis factor -α, interleukin (IL)-6, and IL-8 compared to negative control, while treatment with miR-145 inhibitor decreased the cytokine levels. In conclusion, abnormally expressed miR-145 may be involved in hydrosalpinx-induced ER defects by regulating the inflammatory response.

Effects of Erbuzhuyu Decoction Combined with Acupuncture on Endometrial Receptivity Are Associated with the Expression of miR-494-3p

Background/Aim

Erbuzhuyu decoction (EBZYD) is a traditional Chinese medicine (TCM) formula and has been used in infertility treatment. Meanwhile, acupuncture is also used to treat female infertility. However, it is unclear whether EBZYD combined with acupuncture has better therapeutic effect. The aim of this study was to explore the effect of EBZYD combined with acupuncture and investigate its mechanism in superovulation mice.

Methods

The mice received the treatment of EBZYD, acupuncture, EBZYD combined with acupuncture, or miR-494-3p agomir combined with EBZYD and acupuncture. The blastocysts' number, endometrial microstructure, and endometrial thickness were observed, followed by the detection of endometrial receptivity-related factors, PI3K/Akt/mTOR pathway-related proteins, and miR-494-3p expression using quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Luciferase reporter assay was performed to confirm the targeting relationship between HOXA10 and miR-494-3p.

Results

EBZYD combined with acupuncture treatment could increase the number of blastocysts, pinopodes, endometrial thickness, and the expression of endometrial receptivity-related factors, and the treatment effect of EBZYD combined with acupuncture was better than EBZYD or acupuncture alone. In addition, EBZYD combined with acupuncture treatment activated PI3K/Akt/mTOR pathway and inhibited the expression of miR-494-3p. HOXA10 is one of the target genes of miR-494-3p. Overexpression of miR-494-3p reversed the therapeutic effect of EBZYD combined with acupuncture and suppressed the expression of HOXA10 and the activity of PI3K/Akt/mTOR pathway.

Conclusion

This study suggests that EBZYD combined with acupuncture could improve endometrial receptivity in superovulation mice via miR-494-3p/HOXA10 axis.

Endometriosis and ovarian cancer risk, an epigenetic connection

Endometriosis is a gynecological disorder that affects 176 million women worldwide and 1 in 10 females in the United States. Endometriosis most often affects women of child-bearing age, with most going undiagnosed. Endometriosis also shares many characteristics common to invasive cancer and has been known to be associated with epithelial ovarian cancer. Ovarian cancer is the 11^th most common cancer among women and over 22,000 new cases will be diagnosed within the next year. Women most commonly diagnosed with this cancer are between the ages of 55–64 years, outside the range of the age of women affected with endometriosis. While no known cause of either disease has been established, epigenetic regulation is thought to play a major role in both. This review focuses on epigenetic changes that occur within each individual disease as well as those that are similar in both, suggesting a possible etiological link between the two diseases.

miR-21 reverses impaired decidualization through modulation of KLF12 and NR4A1 expression in human endometrial stromal cells†

Impaired decidualization has been considered a major cause of infertility in adenomyosis. However, the mechanism remains poorly understood. Recent studies suggest that microRNAs (miRNA) play a crucial role in embryo implantation. The aim of the present study was to identify the role of miR-21 in human endometrial stromal cell (hESC) decidualization in vitro. To explore the roles of miR-21 in decidualization, we detected the expression of miR-21 in the endometrium of fertile control and adenomyosis patients, and analyzed the effects of miR-21 on the biological behaviors of hESC decidualization. The results demonstrated that miR-21 was downregulated in the endometrium of adenomyosis patients compared with the control endometrium. miR-21 effectively promoted the expression of the 8Br-cAMP plus medroxyprogesterone acetate (MPA)-induced hESC decidualization marker genes PRL and IGFBP-1 and morphological transformation through the modulation of KLF12 and NR4A1 expression; conversely, inhibition of miR-21 expression compromised hESC decidualization in vitro. In addition, Luciferase reporter, western blotting, and quantitative real-time PCR (qRT-PCR) assays confirmed that miR-21 interacted with the 3' untranslated region of the transcription factor KLF12 and downregulated KLF12 at the transcriptional and translational levels. KLF12 overexpression abolished miR-21-enhanced 8Br-cAMP plus MPA-induced decidualization. Taken together, these results illustrate that miR-21 promotes endometrial decidualization by inhibiting KLF12, and miR-21 overexpression reverses the poor decidual response of hESCs in patients with adenomyosis in vitro.

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.

Identification of MicroRNAs as Potential Biomarkers in Ovarian Endometriosis

Endometriosis, as a prevalent gynecological disease, is characterized by the presence of endometrial-like tissue outside the uterus, causing infertility and considerable pain and affecting the quality of life of women. The pathogenic mechanism has not been fully elucidated, and there are no effective biomarkers for endometriosis. In our study, microRNA (miRNA) expression profiling of 10 ectopic endometrial plasma from patients with ovarian endometriosis and 10 normal plasma from healthy controls was analyzed using a microarray. As a result, 114 differentially expressed miRNAs were identified. Among them, 14 miRNAs were significantly downregulated in patients with ovarian endometriosis, which matched the microarray results. The diagnostic value of the 14 downregulated miRNAs in ovarian endometriosis was evaluated by receiver operating characteristic (ROC) curve analysis, and hsa-let-7i-5p showed the highest area under the ROC curve (AUC) with a value of 0.900. The target genes of the 14 miRNAs were predicted by miRWalk2.0, and the genes that were targeted by at least 2 of the 14 miRNAs were analyzed by function enrichment. The target genes were significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, such as microRNAs in cancer, bladder cancer, and endocrine resistance pathways, and the Gene Ontology (GO) terms such as nucleobase-containing compound metabolic process, cellular nitrogen compound biosynthetic process, and heterocycle metabolic process. The identified 14 differentially expressed miRNAs could be potential biomarkers and therapeutic targets for the diagnosis and treatment of endometriosis.

Endometrial microRNAs and their aberrant expression patterns

MicroRNAs (miRNAs) are a class of small noncoding RNAs that regulate gene expression. They play fundamental roles in several biological processes, including cell differentiation and proliferation, embryo development, organ development, and organ metabolism. Besides regulating the physiological processes, miRNAs regulate various pathological conditions such as tumors, metastases, metabolic diseases, and osteoporosis. Although several studies have been performed on miRNAs, only few studies have described the miRNA expression and functions in human reproductive tract tissues. During menstruation, the human endometrium undergoes extensive cyclic morphological and biochemical modifications before embryo implantation. In addition to the ovarian steroid hormones (estrogen and progesterone), endometrial autocrine or paracrine factors and embryo-derived signals play a significant role in endometrial functions. miRNAs are considered key regulators of gene expression in the human endometrium and implantation process, and their aberrant expression levels are associated with the development of various disorders, including tumorigenesis. In this review, we summarize the studies that show the role of miRNAs in regulating the physiological conditions of the endometrium and the implantation process and discuss the aberrant expression of miRNAs in ectopic pregnancy, endometriosis, and endometrial cancer.

Apoptotic functions of microRNAs in pathogenesis, diagnosis, and treatment of endometriosis

MicroRNAs or miRNAs are a component of the non-coding RNAs family which is engaged in many cellular functions such as cell proliferation, apoptosis, gene expression, signaling pathways, angiogenesis, and etc. Endometriosis is a malignant gynecologic disorder occurring in women before menopausal age. Pathogenesis of this illness is still a discussion subject between the scientists but in our knowledge, microRNAs can be one of the possible involved factors. The purpose of this paper is to investigate the role of apoptotic activities of miRNAs in endometriosis. Accumulative evidence has demonstrated the role of cell proliferation, apoptosis, and invasion in the progression of these diseases. In this review, we looked into the specific role of apoptosis and its related genes and pathways in endometriosis and tied to present an explanation of how miRNAs can affect endometriosis by their apoptotic activities. What we found is that a great extent of miRNAs is involved in this illness and they are responsible for repressing apoptosis and progression of the disease. As a result, miRNAs have two different usages in endometriosis: biomarkers and potential therapeutic targets. In this review we gathered a great amount of evidence to inquire into the role of micro RNAs in inducing apoptosis and how this mechanism can be exerted for therapeutic purposes for endometriosis.

Suppressing HOXA-10 Gene Expression by MicroRNA 135b During the Window of Implantation in Infertile Women

BACKGROUND

Implantation failure has long been identified as a common problem underlying low success rate of IVF. Currently, endometrial receptivity has gained expert attention as it is demonstrated to contribute to successful embryo implantation. MicroRNAs (miRNAs) is known to affect endometrial receptivity through post-transcriptional gene expression regulation. This study aimed to evaluate the expression of miRNA 135b and HOXA-10 during the implantation window in endometrial tissue of infertile women.

METHODS

A total of 14 patients diagnosed with infertility in the gynaecology clinic of Cipto Mangunkusumo and Daya Medika hospitals Jakart, Indonesia were selected as the observed group, and 9 fertile patients were enrolled in the control group. Total RNA was isolated from endometrial tissues collected at the secretory phase of the menstrual cycle. The miRNA 135b and HOXA-10 mRNA expression were measured using quantitative real-time PCR (qPCR). The correlation between these variables was then determined using Pearson's correlation coefficient.

RESULTS

The expression of miRNA 135b in the infertile group was significantly higher by 1.81-fold compared to the control group (p<0.01), whereas, expression of HOXA-10 mRNA was significantly lower in the infertile group compared to the controls (p=0.047). Significant negative correlation was observed between the expression of miRNA 135b and HOXA-10 mRNA in infertile women (p=0.021; r=-0.607).

CONCLUSION

Taken together, this study provides that alteration of miRNA expression is involved in regulating the implantation process partly via modulation of the expression of gene required for implantation.

Deciphering the Role of miRNAs in Endometriosis Pathophysiology Using Experimental Endometriosis Mouse Models

Endometriosis is an enigmatic disease for which we still have a poor understanding on how and why the disease develops. In recent years, miRNAs, small noncoding RNAs which regulate gene expression posttranscriptionally, have been evaluated for their role in endometriosis pathophysiology. This review will provide a brief summary on the role of miRNAs in endometrial physiology and pathophysiology as related to endometriosis. We will then discuss mouse models used in endometriosis research and the incorporation of some of these models in studies which examined the role of miRNAs in endometriosis pathophysiology. We conclude with providing future prospective on the role of mouse models in dissecting the role of miRNAs in endometriosis pathophysiology.

The Role of Exosomes in Diseases Related to Infertility

Exosomes, small extracellular vesicles with diameters of 40-100nm, are generated through the fusion of multivessel with plasma membrane and secreted by a variety of living cells. Exosomes contain lipid bilayer membrane and releasable functionally active proteins, mRNA and microRNAs (miRNAs). This article reviews the latest progress of researches on exosomes in diseases that lead to infertility.

Prognostic significance of microRNA-135 in patients with digestive system cancers: a systematic review and meta-analysis

Background: MicroRNA-135 (miR-135) is a well-known non-coding RNA that has been demonstrated to participate in tumorigenesis and cancer development; however, the clinical prognostic value of miR-135 in digestive system cancers remains controversial. This meta-analysis aims to explore the potential value of miR-135 as a prognostic marker for digestive system cancers.

Methods: The PubMed, Embase, Cochrane Library, and Web of Science databases were searched for eligible articles published before 31 August 2019. Stata 12.0 software was used to analyze the overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RFS) rates to access the prognostic value of miR-135 in digestive system cancers. We then used The Cancer Genome Atlas (TCGA) datasets to validate the meta-analysis results.

Results A total of 1470 patients from 17 studies were included in this meta-analysis. The pooled results showed that enhanced miR-135 expression was significantly associated with poor OR (hazard ratio (HR): 1.790; 95% confidence interval (95% CI): 1.577–2.031; P=0.000), DFS (HR: 1.482; 95% CI: 0.914–2.403; P=0.110), and RFS (HR: 3.994; 95% CI: 1.363–11.697; P=0.012) in digestive system cancers. A sensitivity analysis confirmed the reliability of our findings, and no significant publication bias was observed.

Conclusion: MiR-135 can be used as a novel biomarker for patients with digestive system cancers. We look forward to future large-scale clinical studies that will investigate the prognostic value of miR-135.

MicroRNA-135a promotes proliferation, migration, invasion and induces chemoresistance of endometrial cancer cells

Aims

MicroRNAs play essential roles in tumorigenesis and progression in various cancers including endometrial cancer. Here we assessed the role of miR-135a on proliferation, chemosensitivity, migration and invasion of endometrial cancer cells.

Methods

WST-1 assay was performed to examine the proliferation of HEC-1-B and ISHIKAWA endometrial cancer cells with altered expression of miR-135a, with or without cisplatin treatment. Transwell migration and matrigel invasion assays were used to assess the migration and invasion of endometrial cancer cells. The Caspase-Glo3/7 assay was used to examine the effect of miR-135a on cisplatin-induced apoptosis of endometrial cancer cells. The dual-luciferase reporter assay was conducted to validate the putative binding site.

Results

Upregulation of miR-135a improved the proliferation, and promoted migration and invasion of endometrial cancer cells. Furthermore, miR-135a decreased the sensitivity of HEC-1-B and ISHIKAWA cells after cisplatin treatment. The cisplatin-induced apoptosis in endometrial cancer cells was inhibited by miR-135a by regulation of BAX and Bcl-2 expression. Meanwhile, miR-135a could regulate epithelial to mesenchymal transition (EMT) by altering the expression of E-cadherin, N-cadherin, snail and Vimentin in endometrial cancer cells. Further study showed that the expression levels of PTEN and p-AKT in endometrial cancer cells were changed after aberrant expression of miR-135a.

Conclusion

MiR-135a played important roles in tumorigenesis and disease progression of endometrial cancer by regulating proliferation and chemosensitivy of endometrial cancer cells by targeting AKT signaling pathway. Our study indicates that miR-135a might act as a potential biomarker to predict chemotherapy response and prognosis in endometrial cancer.

Evaluation of miR-135a/b expression in endometriosis lesions

The pathogenesis of endometriosis is not clear; however, microRNAs (miRNAs/miRs) are involved in the pathogenesis. miRNAs are short noncoding RNAs involved in post-transcriptional regulation of gene expression by silencing the expression of target genes. The expression of miR-135a/b is associated with endometrial receptivity and implantation; the expression is also associated with the expression of certain genes, including homeobox protein Hox-A10 (HOXA-10). The present study investigated the expression of miR-135a/b in eutopic and ectopic endometrium tissues throughout the different phases of the menstrual cycle. Samples of ectopic endometriosis lesions and eutopic endometrium tissue from 23 patients who underwent laparoscopic surgery were obtained and analyzed. miRNA was extracted and the expression levels of miR-135a/b were determined by reverse transcription quantitative polymerase chain reaction assays using U6 as a housekeeping control. The expression levels of miR-135a and miR-135b in endometriosis lesions were decreased compared with the levels in endometrium tissue. However, miR-135a/b expression levels were increased in the secretory phase compared with the proliferative phase in endometriosis lesions. The increased expression of miR-135a/b during the secretory phase compared with the proliferative phase suggested that these genes serve a determinant role in the homeostasis of reproductive tissue. Therefore, the expression of genes may affect endometrial functioning, impairing embryo implantation.

The effects of human umbilical cord-derived mesenchymal stem cell transplantation on endometrial receptivity are associated with Th1/Th2 balance change and uNK cell expression of uterine in autoimmune premature ovarian failure mice

Background

To explore the mechanism of human umbilical cord-derived mesenchymal stem cell (hUMSC) transplantation to improve ovarian function and the endometrial receptivity in autoimmune premature ovarian failure (POF) mice.

Methods

The POF model was established in mice treated with zona pellucida 3 polypeptide fragment (zona pellucida 3, ZP3). The hUMSCs were transplanted into the POF mice through tail vein injection. Following the transplantation, the serum hormone levels of follicle stimulating hormone (FSH), estrogen (E₂), progesterone (P), γ-interferon (IFN-γ), interleukin-2 (IL-2), and interleukin-4 (IL-4) were evaluated by ELISA analysis. Morphological changes of ovarian and uterus tissues were examined by HE staining and immunohistochemistry. The expression of Th1/Th2 cytokines of T cells in spleen and CD56⁺CD16⁻ cells (uterine natural killer cells, uNK cells) in uterine was measured by flow cytometry (FCM) and immunohistochemistry. The expression of HOXA10 in uterine endometrium was examined by immunohistochemistry and RT-PCR analysis. The pinopodes of epithelial cells in uterine endometrium were examined by scanning electron microscopy.

Results

Following hUMSC transplantation, the serum levels of E₂, P, and IL-4 were increased but FSH, IFN-γ, and IL-2 levels were decreased in POF mice. Also, the transplantation of hUMSCs caused an increase in total number of healthy follicles and decrease of atresia follicles. The expression of HOXA10 gene was significantly increased but the CD56⁺CD16⁻ uNK cells decreased in the endometrium of uterine. The ratio of Th1/Th2 cytokines was also significantly decreased.

Conclusion

The data suggest that the recovery of ovarian function and endometrial receptivity in POF mice was regulated by the balance of Th1/Th2 cytokines and expression of uNK cells in the endometrium following hUMSC transplantation.

Plasma miRNAs Display Limited Potential as Diagnostic Tools for Endometriosis

CONTEXT

Despite extensive searches for novel noninvasive diagnostics, laparoscopy remains the reference test for endometriosis. Circulating miRNAs are purported endometriosis biomarkers; however, the miRNA species and their diagnostic accuracy differ between studies and have not been validated in independent cohorts.

OBJECTIVE

Identify endometriosis-specific plasma miRNAs and determine their diagnostic test accuracy.

SETTING

Two university-based, public hospitals and a private gynecology practice in Australia.

DESIGN AND PARTICIPANTS

Four phases: (i) Explorative phase. Plasma miRNA menstrual cycle fluctuations were evaluated in women with endometriosis and asymptomatic controls (n = 16). (ii) Biomarker discovery. Endometriosis-specific plasma miRNAs were identified in (a) women with endometriosis and asymptomatic controls (n = 16) and (b) women with and without surgically defined endometriosis (n = 20). (iii) Biomarker selection. Plasma miRNAs with the best diagnostic potential for endometriosis were selected in a surgically defined selection cohort (n = 78). (iv) Biomarker validation. The diagnostic test accuracy of these miRNAs was calculated in an independent, surgically defined validation cohort (n = 119).

RESULTS

Forty-nine miRNAs were differentially expressed in women with endometriosis. Nine maintained dysregulation in the selection cohort, but only three (miR-155, miR574-3p and miR139-3p) did so in the validation cohort. Combined, these three miRNAs demonstrated a sensitivity and specificity of 83% and 51%, respectively.

CONCLUSION

Plasma miRNAs demonstrated modest sensitivity and specificity as diagnostic tests or triage tools for endometriosis. Other groups' findings were not replicated and accorded poorly with our results. Circulating miRNAs demonstrate diagnostic potential, but stringent, standardized methodological approaches are required for the development of a clinically applicable tool.

Increased circulating miR-370-3p regulates steroidogenic factor 1 in endometriosis

Endometriosis is a gynecologic disease common among reproductive-aged women caused by the growth of endometrial tissue outside the uterus. Altered expression of numerous genes and microRNAs has been reported in endometriosis. Steroidogenic factor 1 (SF-1), an essential transcriptional regulator of multiple genes involved in estrogen biosynthesis, is aberrantly increased and plays an important role in the pathogenesis of endometriosis. Here, we show the expression of SF-1 in endometriosis is regulated by miR-370-3p. Sera and tissue were collected from 20 women surgically diagnosed with endometriosis and 26 women without endometriosis. We found that miR-370-3p levels were decreased in the serum of patients with endometriosis while SF-1 mRNA levels were inversely upregulated in endometriotic lesions compared with respective controls. Transfection of primary endometriotic cells with miR-370-3p mimic or inhibitor resulted in the altered expression of SF-1 and SF-1 downstream target genes steroidogenic acute regulatory protein (StAR) and CYP19A1. Overexpression of miR-370-3p inhibited cell proliferation and induced apoptosis in endometriotic cells. This study reveals that miR-370-3p functions as a negative regulator of SF-1 and cell proliferation in endometriotic cells. We suggest a novel therapeutic strategy for controlling SF-1 in endometriosis.

MiR-135 suppresses glycolysis and promotes pancreatic cancer cell adaptation to metabolic stress by targeting phosphofructokinase-1

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human cancers. It thrives in a nutrient-poor environment; however, the mechanisms by which PDAC cells undergo metabolic reprogramming to adapt to metabolic stress are still poorly understood. Here, we show that microRNA-135 is significantly increased in PDAC patient samples compared to adjacent normal tissue. Mechanistically, miR-135 accumulates specifically in response to glutamine deprivation and requires ROS-dependent activation of mutant p53, which directly promotes miR-135 expression. Functionally, we found miR-135 targets phosphofructokinase-1 (PFK1) and inhibits aerobic glycolysis, thereby promoting the utilization of glucose to support the tricarboxylic acid (TCA) cycle. Consistently, miR-135 silencing sensitizes PDAC cells to glutamine deprivation and represses tumor growth in vivo. Together, these results identify a mechanism used by PDAC cells to survive the nutrient-poor tumor microenvironment, and also provide insight regarding the role of mutant p53 and miRNA in pancreatic cancer cell adaptation to metabolic stresses.

Non-coding RNAs in endometriosis: a narrative review

BACKGROUND

Endometriosis is a benign gynaecological disorder, which affects 10% of reproductive-aged women and is characterized by endometrial cells from the lining of the uterus being found outside the uterine cavity. However, the pathophysiological mechanisms causing the development of this heterogeneous disease remain enigmatic, and a lack of effective biomarkers necessitates surgical intervention for diagnosis. There is international recognition that accurate non-invasive diagnostic tests and more effective therapies are urgently needed. Non-coding RNA (ncRNA) molecules, which are important regulators of cellular function, have been implicated in many chronic conditions. In endometriosis, transcriptome profiling of tissue samples and functional in vivo and in vitro studies demonstrate that ncRNAs are key contributors to the disease process.

OBJECTIVE AND RATIONALE

In this review, we outline the biogenesis of various ncRNAs relevant to endometriosis and then summarize the evidence indicating their roles in regulatory pathways that govern disease establishment and progression.

SEARCH METHODS

Articles from 2000 to 2016 were selected for relevance, validity and quality, from results obtained in PubMed, MEDLINE and Google Scholar using the following search terms: ncRNA and reproduction; ncRNA and endometriosis; miRNA and endometriosis; lncRNA and endometriosis; siRNA and endometriosis; endometriosis; endometrial; cervical; ovary; uterus; reproductive tract. All articles were independently screened for eligibility by the authors.

OUTCOMES

This review integrates extensive information from all relevant published studies focusing on microRNAs, long ncRNAs and short inhibitory RNAs in endometriosis. We outline the biological function and synthesis of microRNAs, long ncRNAs and short inhibitory RNAs and provide detailed findings from human research as well as functional studies carried out both in vitro and in vivo, including animal models. Although variability in findings between individual studies exists, collectively, the extant literature justifies the conclusion that dysregulated ncRNAs are a significant element of the endometriosis condition.

WIDER IMPLICATIONS

There is a compelling case that microRNAs, long non-coding RNAs and short inhibitory RNAs have the potential to influence endometriosis development and persistence through modulating inflammation, proliferation, angiogenesis and tissue remodelling. Rapid advances in ncRNA biomarker discovery and therapeutics relevant to endometriosis are emerging. Unravelling the significance of ncRNAs in endometriosis will pave the way for new diagnostic tests and identify new therapeutic targets and treatment approaches that have the potential to improve clinical options for women with this disabling condition.

Metformin Regulates Key MicroRNAs to Improve Endometrial Receptivity Through Increasing Implantation Marker Gene Expression in Patients with PCOS Undergoing IVF/ICSI

To some extent, the use of metformin may improve endometrial receptivity and pregnancy outcomes of women with polycystic ovarian syndrome (PCOS) undergoing in vitro fertilization/intracytoplasmic sperm injection. However, the mechanism is not well-known. The endometrium of metformin-treated group (metformin-treated patients with PCOS) and the control group (non-metformin-treated patients with PCOS) were analyzed for the expression of homeobox A10 (HOXA10) and integrin beta-3 (ITGB3) and differential micro RNA (miRNA) expression profiles. On this basis, miRDB and Target Scan databases were used to predict and screen out that miR-491-3p and miR-1910-3p may target HOXA10 and ITGB3. Furthermore, we verified the effects of metformin on the expression of HOXA10 and ITGB3, and regulatory effects of miR-1910-3p and miR-491-3p on HOXA10 and ITGB3 using Ishikawa cell line. Metformin induced a significant dose-dependent upregulation of HOXA10 and ITGB3. The results from the microarray analyses showed there were 40 differentially expressed miRNAs between the 2 groups. Among them, miR-1910-3p and miR-491-3p were the 2 significantly downregulated miRNAs. Bioinformatics prediction indicated that HOXA10 and ITGB3 are potential target genes for miR-1910-3p and miR-491-3p. In Ishikawa cells transfected with miR-491-3p mimics, the expression of HOXA10 and ITGB3 on both messenger RNA (mRNA) and protein level were lower than those in control group (P < .001). Also, the expression of HOXA10 mRNA and protein was lower in Ishikawa cells transfected with miR-1910-3p mimics (P < .001). However, no significant changes in ITGB3 levels were observed in cells transfected with miR-1910-3p mimics (P > .05). Metformin likely improves endometrial receptivity through downregulating the expression of miR-491-3p and miR-1910-3p, thereby increasing the expression of HOXA10 and ITGB3 in the endometrium of PCOS women.

Endometrial Epithelial Cell Apoptosis Is Inhibited by a ciR8073-miR181a-Neurotensis Pathway during Embryo Implantation

Development of the receptive endometrium (RE) from the pre-receptive endometrium (PE) is essential for embryo implantation, but its molecular mechanisms have not been fully understood. In this study, lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA networks were constructed to explore the functions of potential competing endogenous RNAs (ceRNA) during the development of RE in dairy goats. We observed that circRNA8073 (ciR8073) decreased the levels of miR-181a by acting as a miRNA sponge. This effect indirectly increased the expression of neurotensin in endometrial epithelial cells (EECs). Neurotensin then inhibited EEC apoptosis by increasing the expression of BCL-2/BAX in favor of BCL-2 via the MAPK pathway and also induced increased expression of leukemia-inhibitory factor, cyclo-oxygenase 2, vascular endothelial growth factor A, and homeobox A10. We have thus identified a ciR8073-miR181a-neurotensin pathway in the endometrium of dairy goats. Through this pathway, ciR8073 functions as a ceRNA that sequesters miR-181a, thereby protecting neurotensin transcripts from miR-181a-mediated suppression in EECs.

The nervous system and genomics in endometriosis

Endometriosis is a gynaecological disease that occurs in approximately 10% to 15% of women of reproductive age and up to 47% of infertile women. The presence of implants of endometrial-like glands and stroma outside the uterus, characteristic of this disease, induce a wide variety of symptoms, mainly pelvic pain and infertility. Women suffering from this condition experience great distress, which significantly affects their quality of life. Numerous studies attempting to decipher the pathogenic mechanisms of endometriosis have been conducted around the world, yet its aetiology still remains unknown. It is widely believed that in women with endometriosis, the endometrium has characteristic features that allow the formation of implants once fragments have entered the peritoneal cavity through retrograde menstruation. Furthermore, a strong genetic tendency to develop the disease has been reported among patients and first-degree relatives. Thanks to the recent technological advances achieved in genomics and bioinformatics, a number of studies have had the potential to analyse several aspects of the pathogenesis of endometriosis from a genetic perspective. Due to the recent identification of nerve fibres in the endometrium of women with endometriosis, research on the neurogenesis of the disease has increased in the past few years. However, the genetic aspects of nerve growth in endometriosis have not been analysed in depth and further research providing important insights into the mechanisms that mediate pain in affected patients has the potential to contribute substantially to the future management of the condition.

Endometrial miR-543 Is Downregulated During the Implantation Window in Women With Endometriosis-Related Infertility

BACKGROUND

Differentially expressed microRNAs (miRNAs) and their target mRNAs may lead to alterations in normal physiological status of the tissues and initiate pathological processes. The aim of this study was to investigate the expression of the most relevant miRNAs in the eutopic endometrial tissue during the window of implantation in women with endometriosis-related infertility.

METHODS

In the study, 76 infertile women with a regular menstrual cycle were recruited from the Center for Reproductive Medicine, Peking University Third Hospital between January 2014 and June 2016. We performed a combined messenger RNA and miRNA microarray and bioinformatics analysis of eutopic endometrium in 6 women with and without endometriosis-related infertility at the time of implantation window. Quantitative real-time polymerase chain reaction arrays were utilized to examine the expression levels of selected miRNAs (from 35 patients with endometriosis and 35 disease-free individuals at different menstrual stages).

RESULTS

Five differentially expressed miRNAs (miR-142-5p, miR-146a-5p, miR-1281, miR-940, and miR-4634) were significantly upregulated, whereas miR-543 was significantly downregulated in the eutopic endometrium during the window of implantation in patients with endometriosis. Further analysis showed that miR-543 was significantly upregulated at the peri-implantation phase compared with that at proliferative phase in the endometrium of disease-free patients (P < .05). However, the expression level of miR-543 was significantly decreased in patients with endometriosis (P < .05), especially downregulated at the window of implantation phase (P < .05).

CONCLUSIONS

miR-543 plays an important role during embryo implantation process and is associated with endometrial receptivity. Downregulation of miR-543 may affect embryo implantation, resulting in the pathogenesis of endometriosis-related infertility.

The relationship between the expression levels of miR-135a and HOXA10 gene in the eutopic and ectopic endometrium

BACKGROUND

The study of microRNA expression can be effective in the diagnosing and treating different diseases. miR-135a is one of the most important micro-ribonucleic acids involved in endometriosis. Among the genes that become the target of the miR-135a and are subjected to changes in the endometrium of patients with endometriosis is HOXA10 gene which is expressed in the endometrium in response to steroid hormones.

OBJECTIVE

The aim of this study was to evaluate the expression of miR-135a and its relationship with the level of HOXA10 gene expression in both endometrial ectopic and eutopic tissues in patients with endometriosis compared to the control samples.

MATERIALS AND METHODS

In this prospective case-control study, both case-eutopic and case-ectopic tissue samples were obtained from 17 women with endometriosis and the eutopic endometrial tissue was sampled from 17 women with normal endometrium as the control group. The gene's expression of miR-135a and HOXA10 were investigated using quantitative reverse transcription PCR (q-RT PCR).

RESULTS

A significant decrease in the expression of HOXA10 gene was detected in case-eutopic during the luteal phase compared to the control samples (p=0.001), while in the case-ectopic, the expression of this gene was increased (p=0.681) compared to the control samples. In addition, the expression miR-135a in the luteal phase showed a remarkable increase in the case-eutopic endometrial tissue (p=0.026) as well as a significant decrease in the case-ectopic endometrial tissue compared to the control samples (p=0.008).

CONCLUSION

Considering the inverse relations between the over-expression of miR-135a and the reduction of HOXA10, it seems that miR-135a may be applied as an endometrial diagnostic and therapeutic biomarker.

Serum MicroRNA Biomarkers Regulated by Simvastatin in a Primate Model of Endometriosis

Endometriosis is a chronic inflammatory and estrogen-dependent disease that causes pain and infertility in reproductive-aged women. Due to the delay in diagnosis, there is a pressing need for accurate biomarkers. Detection of serum noncoding RNA molecules such as microRNAs (miRNAs) shows promise as a noninvasive diagnostic strategy; we previously identified miRNAs that are highly sensitive and specific biomarkers for the disease. In this study, we investigate the expression of these miRNAs in a nonhuman primate model of endometriosis. As part of a pilot study evaluating simvastatin for the treatment of endometriosis, the disease was induced in 16 baboons by induction laparoscopy and the animals were divided into 2 groups. One group was treated with simvastatin for 90 days, while the second group received vehicle only. Endometriosis was evaluated after 3 months by laparoscopy. Serum samples were analyzed for 9 circulating miRNAs using quantitative real time-polymerase chain reaction, focusing on the miRNAs we found to be dysregulated in human endometriosis. In the simvastatin-treated endometriosis group, levels of miR-150-5p and miR-451a were decreased, while miR-3613-5p levels were increased compared to the untreated endometriosis group. The changes in circulating miRNA expression patterns parallel our previous results in human patients and show that specific miRNAs correlate with endometriosis severity and reverted toward control expression levels after simvastatin treatment. This is the first report showing serum miRNA expression normalized in response to endometriosis treatment, supporting the potential for this class of biomarkers to be used both to diagnose endometriosis and to monitor its progression and response to therapy.

Calpain7 impairs embryo implantation by downregulating β3-integrin expression via degradation of HOXA10

Endometriosis (ENDO) is a common gynecological disease that causes infertility in many women. Previous studies noted that the dysregulation of Homeo box A10 (HOXA10) in the endometrium of women with ENDO was involved in the failure of embryo implantation. However, the mechanism by which HOXA10 expression is reduced in women with ENDO is still poorly understood. Here we found that a member of the calcium (Ca²⁺)-dependent cysteine protease family calpain7 (CAPN7), negatively correlated with HOXA10, was highly expressed in the endometrium of infertile women with ENDO and was significantly downregulated during the window of embryo implantation in mice. Overexpression of CAPN7 in Ishikawa cells or in the uterus of mice inhibited embryo implantation in vitro and in vivo. In the current study, we identified a sequence rich in proline, glutamic acid, serine, and threonine (PEST sequence) that enhanced the Ca²⁺-dependent degradation of HOXA10 by CAPN7. Furthermore, the interaction between HOXA10 and CAPN7 repressed the transcriptional activity and protein stability of HOXA10. In contrast, the administration of the calpain inhibitor ALLN reversed the CAPN7-induced HOXA10 degradation. Moreover, truncation of the PEST motif in HOXA10 abolished its CAPN7-dependent proteolysis. These studies reveal a novel pattern of HOXA10 regulation via PEST sequence-mediated calpain proteolysis that was demonstrated to be reversed by a calpain inhibitor. Thus, the inhibition of CAPN7-induced HOXA10 degradation may represent a novel potential therapeutic method to improve impaired embryo implantation in women with ENDO.

The miRNA Mirage: How Close Are We to Finding a Non-Invasive Diagnostic Biomarker in Endometriosis? A Systematic Review

Background: Endometriosis is a common disorder of the reproductive age group, characterised by the presence of ectopic endometrial tissue. The disease not only causes enormous suffering to the affected women, but also brings a tremendous medical and economic burden to bear on society. There is a long lag phase between the onset and diagnosis of the disease, mainly due to its non-specific symptoms and the lack of a non-invasive test. Endometriosis can only be diagnosed invasively by laparoscopy. A specific, non-invasive test to diagnose endometriosis is an unmet clinical need. The recent discovery of microRNAs (miRNAs) as modulators of gene expression, and their stability and specificity, make them an attractive candidate biomarker. Various studies on miRNAs in endometriosis have identified their cardinal role in the pathogenesis of the disease, and have proposed them as potential biomarkers in endometriosis. Rationale/Objectives: The aims of this review were to study the role of circulatory miRNAs in endometriosis, and bring to light whether circulatory miRNAs could be potential non-invasive biomarkers to diagnose the disease. Search methods: Three databases, PubMed, EMBASE, and BIOSIS were searched, using a combination of Mesh or Emtree headings and free-text terms, to identify literature relating to circulating miRNAs in endometriosis published from 1996 to 31 December 2017. Only peer-reviewed, full-text original research articles in English were included in the current review. The studies meeting the inclusion criteria were critically assessed and checked using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies) tool. The dysregulated miRNAs were assessed regarding the concordance between the various studies and their role in the disease. Outcomes: Nine studies were critically analysed, and 42 different miRNAs were found to be dysregulated in them, with only one common miRNA (miR-20a) differentially expressed in more than one study. miR-17-5p/20a, miR-200, miR-199a, miR-143, and miR-145 were explored for their pivotal role in the aetiopathogenesis of endometriosis. Wider implications: It is emerging that miRNAs play a central role in the pathogenesis of endometriosis and have the potential of being promising biomarkers. Circulating miRNAs as a non-invasive diagnostic tool may shorten the delay in the diagnosis of the disease, thus alleviating the suffering of women and reducing the burden on health care systems. However, despite numerous studies on circulating miRNAs in endometriosis, no single miRNA or any panel of them seems to meet the criteria of a diagnostic biomarker. The disagreement between the various studies upholds the demand of larger, well-controlled systematic validation studies with uniformity in the research approaches and involving diverse populations.

MicroRNA expression profiling in placenta and maternal plasma in early pregnancy loss

Early pregnancy loss (EPL), also termed early miscarriage, is determined as the unintentional expulsion of an embryo or fetus prior to the 12th week of gestation. EPL frequency is ~15% in pregnancies. Fetal development and growth is associate with placental function and vessel development; therefore, the placental genome would represent a useful miscarriage model for (epi)genetic and genomic studies. An important factor of placental development and function is epigenetic regulation of gene expression. microRNAs (miRNAs) are the primary epigenetic regulators which have an important role in placental development and function. In the present study, maternal plasma and villous tissue were collected from 16 EPL cases in 6th-8th gestational weeks (GWs) and 8 abortions (control group) in 6th-8th GWs. Detection of the differences in miRNA expression was performed using microarrays and dysregulated miRNAs were validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). miRNA microarray findings revealed that four miRNAs, including hsa-miRNA (miR)-125a-3p, hsa-miR-3663-3p, hsa-miR-423-5p and hsa-miR-575 were upregulated in tissue samples. In maternal plasma, two miRNAs (hsa-let-7c, hsa-miR-122) were upregulated and one miRNA (hsa-miR-135a) was downregulated. A total of 6 out of 7 dysregulated miRNAs were validated using RT-qPCR. The target genes of these dysregulated miRNAs were detected using the GeneSpring database. The aim of the present study was to detect dysregulated miRNAs in maternal plasma and villous cells and identify the target genes of dysregulated miRNAs and their associated pathways. The target gene analyses have revealed that the affected genes are primarily associated with cell migration, proliferation, implantation, adhesion, angiogenesis and differentiation and all are involved with EPL pathogenesis. Therefore, the present study may contribute to the understanding of the molecular mechanisms which lead to EPL.

Future Directions in Endometriosis Research and Therapeutics

Background

Endometriosis is a disease common among women of reproductive age characterized by pain, anxiety and infertility. Defined as the growth of endometrial tissue in ectopic locations, endometriosis remains an enigmatic disease for which current treatments are less than ideal. Much of these shortcomings to current therapy stem from our incomplete understanding on the pathogenesis of the disease. It is generally accepted that endometriosis is an estrogen-dependent disease and, as such, the majority of treatment approaches aim at reducing estrogen action and/or production. Unfortunately, this approach is not effective in all women with endometriosis and in those women where success is achieved with their use, there is potential for health-comprising side effects.

Objective

The objective of this review is to summarize current approaches for treatment of endometriosis, discuss their limitations and potential reasons for lack of progress towards better therapeutics for this disease.

Results

In this review we summarize the current approaches for treatment of endometriosis, discuss their limitations and potential reasons for lack of progress towards better therapeutics for this disease.

Conclusion

Based upon the current state of knowledge, there is a strong necessity for through assessment at the level of the genome, miRNAome and proteome as well as the importance of integrating clinically-relevant endpoints in future studies which evaluate potential endometriosis therapies in experimental models of endometriosis.