Tissue and circulating microRNA influence reproductive function in endometrial disease

Diagnostic value of the combination of circulating serum miRNAs and CA125 in endometriosis

Circulating microRNAs (miRNAs) can serve as noninvasive biomarkers for endometriosis, but their diagnostic and prognostic values require investigation. This study evaluated the potential of 6 miRNAs in diagnosing endometriosis and predicting fertility. The study included patients with endometriosis (stages I-IV) and controls admitted to Sun Yat-Sen Memorial Hospital between May 2013 and March 2014. The serum expression levels of 6 miRNAs (miR-199a, miR-145*, miR-122, miR-9*, miR-141*, and miR-542-3p) were determined using qRT-PCR. Receiver operating characteristics curves were used to determine the diagnostic accuracy. The study included 155 patients with endometriosis and 77 controls. The model combining miR-199a, miR-122, miR-145*, and miR-141* with the carbohydrate antigen 125 (CA125) exhibited 81.8% sensitivity and 92.6% specificity and an area under the curve of 0.939 for diagnosing endometriosis. When combining miR-199a, miR-122, miR-145*, miR-542-3p, and CA125, the receiver operating characteristics curve showed an area under the curve of 0.759 and 79.6% sensitivity and 73.5% specificity for stage I/II versus III/IV endometriosis. Circulating miRNA levels were associated with pelvic adhesions (miR-199a, P < .05), lesion distribution (miR-9*, miR-145*, and miR-141*; all P < .05), and the presence of deep infiltrating endometriosis (miR-199a and miR-122; both P < .001). The expression levels of miR-199a, miR-122, and miR-542-3p decreased with an increasing endometriosis fertility index. The model combining circulating miRNAs (miR-199a, miR-122, miR-145*, and miR-141*) and CA125 is promising for diagnosing endometriosis and its severity. miR-199a, miR-122, and miR-542-3p were associated with the endometriosis fertility index and might be used to predict fertility preoperatively, but these results require confirmation.

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

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

CXADR promote epithelial-mesenchymal transition in endometriosis by modulating AKT/GSK-3β signaling

Endometriosis is a benign high prevalent disease exhibiting malignant features. However, the underlying pathogenesis and key molecules of endometriosis remain unclear. By integrating and analysis of existing expression profile datasets, we identified coxsackie and adenovirus receptor (CXADR), as a novel key gene in endometriosis. Based on the results of immunohistochemistry (IHC), we confirmed significant down-regulation of CXADR in ectopic endometrial tissues obtained from women with endometriosis compared with healthy controls. Further in vitro investigation indicated that CXADR regulated the stability and function of the phosphatases and AKT inhibitors PHLPP2 (pleckstrin homology domain and leucine-rich repeat protein phosphatase 2) and PTEN (phosphatase and tensin homolog). Loss of CXADR led to phosphorylation of AKT and glycogen synthase kinase-3β (GSK-3β), which resulted in stabilization of an epithelial-mesenchymal transition (EMT) factor, SNAIL1 (snail family transcriptional repressor 1). Therefore, EMT processs was induced, and the proliferation, migration and invasion of Ishikawa cells were enhanced. Over-expression of CXADR showed opposite effects. These findings suggest a previously undefined role of AKT/GSK-3β signaling axis in regulating EMT and reveal the involvement of a CXADR-induced EMT, in pathogenic progression of endometriosis.

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

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

Metal-Organic Framework UiO-66-Mediated Dual-Signal Ratiometric Electrochemical Sensor for microRNA Detection with DNA Walker Amplification

Electrochemical nanotags with strong signal input are necessary for a ratiometric electrochemical sensor to overcome the drawbacks of inaccurate detection results. In this paper, the metal-organic framework (MOF) UiO-66 was utilized as an electrochemical signal tag. A stable and strong current response at +0.9 V can be detected in neutral conditions. MicroRNA (miRNA) was employed as the model analyte. Herein, an enzyme-free DNA-walker-based ultrasensitive ratiometric electrochemical biosensor in combination with Zr MOF (UiO-66) signal tags to detect miRNA was demonstrated. In the presence of miRNA, the autonomous walker movement can be initiated by miRNA, leading to the release of biotin-modified fragments. Thus, streptavidin-labeled UiO-66 nanomaterials were not bound to the electrode, generating a low signal response of UiO-66 at +0.9 V. However, the current signal of electrolyte solution as reference at +0.2 V was increased due to the enhancement of electrode conductivity. This ratiometic sensor demonstrated high sensitivity, selectivity, and reproducibility. It can eliminate the disturbance of environmental factors and basic electrode characteristics, providing more accurate signals. A limit of detection (LOD) of 0.17 fM was achieved. Moreover, the method was also used to detect miRNA-21 spiked in real serum samples.

Non-coding RNAs and their cross-talks impacting reproductive health of women

Non-coding RNAs (ncRNAs) work as crucial posttranscriptional modulators of gene expression regulating a wide array of biological processes that impact normal physiology, including reproductive health. The health of women, especially reproductive health, is now a prime focus of society that ensures the females' overall physical, social, and mental well-being. Furthermore, there has been a growing cognizance of ncRNAs' possible applications in diagnostics and therapeutics of dreaded diseases. Hence, understanding the functions and mode of actions of ncRNAs in the context of women's health will allow us to develop effective prognostic and therapeutic strategies that will enhance the quality of life of women. Herein, we summarize recent progress on ncRNAs, such as microRNAs (miRNAs) and long ncRNAs (lncRNAs), and their implications in reproductive health by tying the knot with lifestyle factors that affect fertility complications, pregnancy outcomes, and so forth. We also discourse the interplay among the RNA species, especially miRNAs, lncRNAs, and protein-coding RNAs, through the competing endogenous RNA regulations in diseases of women associated with maternal and fetal health. This review provides new perspectives correlating ncRNAs, lifestyle, and reproductive health of women, which will attract future studies to improve women's lives. This article is categorized under: RNA in Disease and Development > RNA in Disease Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.

A critical appraisal of the circulating levels of differentially expressed microRNA in endometriosis†

Endometriosis is a common gynecological condition characterized by estrogen dependence, chronic pelvic pain, infertility, and diagnostic delay of between 5.4 and 12 years. Despite extensive study, no biomarker, either alone or in combination with other markers, has proven superior to laparoscopy for the diagnosis of endometriosis. Recent studies report that circulating levels of differentially expressed microRNA (miRNA) in women with endometriosis compared with controls are potential diagnostic tools. However, the lack of replication and absence of validated differential expression in novel study populations have led some to question the diagnostic value of miRNA. To elucidate potential reasons for the lack of replication of study results and explore future directions to enhance replicability of circulating miRNA results, we carried out an electronic search of the miRNA literature published between 2000 and 2020. Eighteen studies were identified in which 63 different miRNAs were differentially expressed in the circulation of women with endometriosis compared with controls. However, the differential expressions of only 14 miRNAs were duplicated in one or more studies. While individual miRNAs lacked diagnostic value, miRNA panels yielded sensitivity and specificity equal to or better than laparoscopy in five studies. Important differences in study design, sample processing, and analytical methods were identified rendering direct comparisons across studies problematic and could account for the lack of reproducibility of study results. We conclude that while the results of miRNA studies to date are encouraging, refinements to study design and analytical methods should enhance the reliability of circulating miRNA for the diagnosis of endometriosis.

Molecular dysregulations underlying the pathogenesis of endometriosis

Endometriosis is a crippling disease characterized by the presence of endometrium-like tissue or scar outside the uterine cavity, commonly confined to the peritoneal and serosal surfaces of the pelvic organs. 10-15% of women in reproductive age are estimated to be affected by endometriosis. Most of these patients present with infertility and suffer from pelvic pain. The benign disease rarely progresses to malignancy. Regardless of its high prevalence, the pathogenesis of the disease is not fully understood. Treatment options for endometriosis are limited and are often based on a symptomatic approach. The unavailability of proper diagnostic approaches, fewer therapeutic options, and sparse understanding of molecular alterations are responsible for the continued disease burden. Exploring the molecular elements causing the pathogenesis of endometriosis may lead to a number of breakthroughs in the treatment of the illness, such as the discovery of new biomarkers for diagnosis and therapeutic targets that can be a guide to better prognosis and reduced recurrence. The goal of this review is to provide the reader a critical understanding of the disease by summarizing the genetic, immunological, hormonal, and epigenetic deregulations that support the molecular basis for development of endometriotic cyst, with a special focus on the study models needed to analyze these changes in the endometriotic microenvironment.

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.

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.

A novel platform for discovery of differentially expressed microRNAs in patients with repeated implantation failure

OBJECTIVE

To identify predictor microRNAs (miRNAs) from patients with repeated implantation failure (RIF).

DESIGN

Systemic analysis of miRNA profiles from the endometrium of patients undergoing in vitro fertilization (IVF).

SETTING

University research institute, private IVF center, and molecular testing laboratory.

PATIENT(S)

Twenty five infertile patients in the discovery cohort and 11 patients in the validation cohort.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

A signature set of miRNA associated with the risk of RIF.

RESULT(S)

We designed a reproductive disease-related PanelChip to access endometrium miRNA profiles in patients undergoing IVF. Three major miRNA signatures, including hsa-miR-20b-5p, hsa-miR-155-5p, and hsa-miR-718, were identified using infinite combination signature search algorithm analysis from 25 patients in the discovery cohort undergoing IVF. These miRNAs were used as biomarkers in the validation cohort of 11 patients. Finally, the 3-miRNA signature was capable of predicting patients with RIF with an accuracy >90%.

CONCLUSION(S)

Our findings indicated that specific endometrial miRNAs can be applied as diagnostic biomarkers to predict RIF. Such information will definitely help to increase the success rate of implantation practice.

Circulating microRNAs as candidate biomarkers for the ovarian response during in vitro fertilization

MicroRNAs (miRNAs) in the let-7 family have established regulatory roles in pregnancy; in this study, we evaluated whether miRNAs detectable in the circulation are associated with the ovarian response to stimulation.In total, 25 patients with infertility were divided into 3 groups: poor response (n = 9), moderate response (n = 8), and hyper-response (n = 8). Serum and endometrial tissue samples on the second day of the menstrual phase, serum samples during the mid-luteal phase, and follicular fluid samples were collected from women undergoing in vitro fertilization. The levels of let-7g-5p, let-7f-5p, and let-7i-5p in were evaluated.The levels of circulating let-7g-5p,7f-5p, and 7i-5p in the basal sera were significantly higher in the moderate ovarian response group than in the poor response group (P < .05). The expression levels of these genes tended to be down-regulated in the mid-luteal phase in the high response group (P < .05). There were no significant differences in expression levels in the endometria and follicular fluid among groups (P > .05).Circulating let-7g-5p, 7f-5p, and 7i-5p were differentially expressed between the moderate response group and the high and poor response groups. The combination of these serum miRNAs during the menstrual phase might serve as a non-invasive predictive marker for the ovarian response to in vitro fertilization.

Identifying biomarkers for predicting successful embryo implantation: applying single to multi-OMICs to improve reproductive outcomes

BACKGROUND

Successful embryo implantation is a complex process that requires the coordination of a series of events, involving both the embryo and the maternal endometrium. Key to this process is the intricate cascade of molecular mechanisms regulated by endocrine, paracrine and autocrine modulators of embryonic and maternal origin. Despite significant progress in ART, implantation failure still affects numerous infertile couples worldwide and fewer than 10% of embryos successfully implant. Improved selection of both the viable embryos and the optimal endometrial phenotype for transfer remains crucial to enhancing implantation chances. However, both classical morphological embryo selection and new strategies incorporated into clinical practice, such as embryonic genetic analysis, morphokinetics or ultrasound endometrial dating, remain insufficient to predict successful implantation. Additionally, no techniques are widely applied to analyse molecular signals involved in the embryo-uterine interaction. More reliable biological markers to predict embryo and uterine reproductive competence are needed to improve pregnancy outcomes. Recent years have seen a trend towards 'omics' methods, which enable the assessment of complete endometrial and embryonic molecular profiles during implantation. Omics have advanced our knowledge of the implantation process, identifying potential but rarely implemented biomarkers of successful implantation.

OBJECTIVE AND RATIONALE

Differences between the findings of published omics studies, and perhaps because embryonic and endometrial molecular signatures were often not investigated jointly, have prevented firm conclusions being reached. A timely review summarizing omics studies on the molecular determinants of human implantation in both the embryo and the endometrium will help facilitate integrative and reliable omics approaches to enhance ART outcomes.

SEARCH METHODS

In order to provide a comprehensive review of the literature published up to September 2019, Medline databases were searched using keywords pertaining to omics, including 'transcriptome', 'proteome', 'secretome', 'metabolome' and 'expression profiles', combined with terms related to implantation, such as 'endometrial receptivity', 'embryo viability' and 'embryo implantation'. No language restrictions were imposed. References from articles were also used for additional literature.

OUTCOMES

Here we provide a complete summary of the major achievements in human implantation research supplied by omics approaches, highlighting their potential to improve reproductive outcomes while fully elucidating the implantation mechanism. The review highlights the existence of discrepancies among the postulated biomarkers from studies on embryo viability or endometrial receptivity, even using the same omic analysis.

WIDER IMPLICATIONS

Despite the huge amount of biomarker information provided by omics, we still do not have enough evidence to link data from all omics with an implantation outcome. However, in the foreseeable future, application of minimally or non-invasive omics tools, together with a more integrative interpretation of uniformly collected data, will help to overcome the difficulties for clinical implementation of omics tools. Omics assays of the embryo and endometrium are being proposed or already being used as diagnostic tools for personalised single-embryo transfer in the most favourable endometrial environment, avoiding the risk of multiple pregnancies and ensuring better pregnancy rates.

The role of the serum exosomal and endometrial microRNAs in recurrent implantation failure

OBJECTIVE

It has been identified that endometrium specific microRNAs have different expression levels in endometrial tissues and maternal serum during endometrial cycle. The aim of this study was to analyze microRNA expression levels in recurrent implantation failure patients and healthy controls endometrial samples for enlightening the aetiopathogenesis of the disease. The second aim was to search for a potential noninvasive molecular biomarker in early diagnosis and treatment of Recurrent Implantation Failure (RIF) patients.

METHODS

Endometrium and serum samples in two different phases (PP; proliferative phase and SP; secretory phase) from the same cases (RIF; n = 12 and Control; n = 8) were obtained. The expression levels of the microRNA by RT-qPCR method were measured. The expression levels of the healthy controls and study group were compared. Lastly performed target genes analysis of significantly dysregulated miRNA by target analyze databases for obtained related biological pathways.

RESULTS

This study showed that has-miR-145, has-miR-23b, has-miR-31 and has-miR-30b were significantly up-regulated in PP and down-regulated in SP endometrium samples. In serum samples, has-miR-145 and hsa-miR-23b were significantly down-regulated in both of PP and SP. Target gene and pathway analysis for dysregulated miRNAs identified important, validated and predicted genes for the implantation process.

CONCLUSIONS

This study is the first study to obtain endometrium and serum samples in two different phases from the same cases and measure the candidate miRNAs expression. Our finding suggests that expression level of four candidate miRNAs may be involved in RIF development in women. Furthermore, these miRNAs can be potential biomarker for early diagnosis of RIF patients.

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.

Genetic, Epigenetic, and Steroidogenic Modulation Mechanisms in Endometriosis

Endometriosis is a chronic gynecological disease, affecting up to 10% of reproductive-age women. The exact cause of the disease is unknown; however, it is a heritable condition affected by multiple genetic, epigenetic, and environmental factors. Previous studies reported variations in the epigenetic patterns of numerous genes known to be involved in the aberrant modulation of cell cycle steroidogenesis, abnormal hormonal, immune and inflammatory status in endometriosis, apoptosis, adhesion, angiogenesis, proliferation, immune and inflammatory processes, response to hypoxia, steroidogenic pathway and hormone signaling are involved in the pathogenesis of endometriosis. Accumulating evidence suggest that various epigenetic aberrations may contribute to the pathogenesis of endometriosis. Among them, DNA methyltransferases, histone deacetylators, and non-coding microRNAs demonstrate differential expression within endometriotic lesions and in the endometrium of patients with endometriosis. It has been indicated that the identification of epigenetic differences within the DNA or histone proteins may contribute to the discovery of a useful prognostic biomarker, which could aid in the future earlier detection, timely diagnosis, and initiation of a new approach to the treatment of endometriosis, as well as inform us about the effectiveness of treatment and the stage of the disease. As the etiology of endometriosis is highly complex and still far from being fully elucidated, the presented review focuses on different approaches to identify the genetic and epigenetic links of endometriosis and its pathogenesis.

Dioxin and endometriosis: a new possible relation based on epigenetic theory

Endometriosis is a chronic disease characterized by the growth of endometrial-like glands and stroma outside the uterine cavity. Nowadays, the exact etiology of endometriosis is unclear and the interaction between a variety of environmental physical and chemical compounds may potentially promote the disease in women with an individual susceptibility. The first demonstration of a relation between an environmental factor and endometriosis was obtained with the chronic dietary exposure of a primate colony to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Besides the well-known dioxin's pathway of action, several papers are focusing on the role of epigenetic mechanisms, a way through which the genome responds to the environment and can lead to permanent changes in gene expression until affecting the phenotypes or cause disease. In this review, we focus on the possible role of dioxin epigenetics modification in endometriosis.

An Anti-inflammatory microRNA Signature Distinguishes Group 3 Innate Lymphoid Cells From Natural Killer Cells in Human Decidua

Innate lymphoid cells (ILCs) are a heterogeneous subset of lymphocytes deeply implicated in the innate immune responses to different pathogens, in lymphoid organogenesis and in the maintenance of tissue homeostasis. Group 3 innate lymphoid cells (ILC3) have been detected in human decidua, where they play a role in the early inflammatory phase favoring implantation and tissue remodeling as well as in the subsequent regulatory phase preventing fetal rejection and supporting neoangiogenesis. A balance between inflammation and immune tolerance is required to maintain pregnancy, thus maternal immune system must be controlled by finely tuned mechanisms. microRNAs (miRNAs) are small non-coding RNAs with important regulatory roles in immune cells, but their function in decidual ILC3 (dILC3) and in decidual NK (dNK) cells is still undefined. Here, we examined the miRNome by microarray in these cells during the first trimester of pregnancy and compared with miRNA profiles of peripheral blood NK (pbNK) cells from pregnant women. We show that distinct miRNA profiles could clearly distinguish dILC3 from NK cells. Correlation analyses revealed that dNK and pbNK miRNome profiles are more similar to each other as compared to dILC3. In particular, we identified 302 and 279 mature miRNAs differentially expressed in dILC3 as compared to dNK and pbNK, respectively. The expression of miR-574-3p and the miR-99b/let-7e/miR-125a miRNA cluster resulted the most increased in dILC3. Remarkably, gene ontology analysis and pathway enrichments of miRNA targets revealed an involvement of these miRNAs in the promotion of anti-inflammatory responses. In agreement to this finding, we also found a higher expression of the anti-inflammatory miR-146a-5p in dILC3 with respect to NK cells. Overall, our data identified specific miRNA signatures distinguishing dILC3, dNK, and pbNK cells. Our data suggest the existence of a tight epigenetic control mediated by miRNAs in dILC3, potentially acting as a brake to prevent exaggerated inflammatory responses and to maintain the immune homeostasis in the early phases of pregnancy.

Up-regulation of miR-145 may contribute to repeated implantation failure after IVF-embryo transfer by targeting PAI-1

RESEARCH QUESTION

Repeated implantation failure (RIF) is a major limiting factor in assisted reproductive technology. As miR-145 (also known as MIR145) is up-regulated in patients with RIF, this study asked, what is the molecular mechanism underlying the affect of miR-145 on embryo implantation in RIF?

DESIGN

Ishikawa cells were infected with lentivirus containing miR-145 and miR-145 NC. Massive transcriptome data analyses and bioinformatics analysis were used to search for a potential candidate target of miR-145. The expression of the potential candidate target was detected using quantitative reverse transcription PCR (qRT-PCR) and western blotting in the Ishikawa cells infected with lentivirus containing miR-145 or miR-145 NC. Subsequently, a dual luciferase reporter assay was performed to verify whether the potential candidate target was a novel direct target of miR-145. In addition, expression of PAI-1 (plasminogen activator inhibitor 1, also known as SERPINE1) in endometrial tissue from women with RIF and in control endometrial tissue was examined using qRT-PCR and immunohistochemistry.

RESULTS

Based on massive transcriptome data analyses and bioinformatics analysis, PAI-1 was regarded as a potential candidate target of miR-145. miR-145 overexpression was achieved in Ishikawa cells. PAI-1 was confirmed as a direct target of miR-145 by bioinformatic analysis, qRT-PCR, western blotting and dual luciferase reporter assay. Further, results from the clinical sample indicated that at both the mRNA and protein levels, PAI-1 expression was down-regulated in endometrial tissues from women with RIF compared with control group women, and this was negatively related to miR-145 expression.

CONCLUSIONS

The study results suggests that miR-145 may target and down-regulate PAI-1 expression and influence embryo implantation in women with RIF who are undergoing IVF.

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.

The Pathogenesis of Endometriosis: Molecular and Cell Biology Insights

The etiopathogenesis of endometriosis is a multifactorial process resulting in a heterogeneous disease. Considering that endometriosis etiology and pathogenesis are still far from being fully elucidated, the current review aims to offer a comprehensive summary of the available evidence. We performed a narrative review synthesizing the findings of the English literature retrieved from computerized databases from inception to June 2019, using the Medical Subject Headings (MeSH) unique ID term “Endometriosis” (ID:D004715) with “Etiology” (ID:Q000209), “Immunology” (ID:Q000276), “Genetics” (ID:D005823) and “Epigenesis, Genetic” (ID:D044127). Endometriosis may origin from Müllerian or non-Müllerian stem cells including those from the endometrial basal layer, Müllerian remnants, bone marrow, or the peritoneum. The innate ability of endometrial stem cells to regenerate cyclically seems to play a key role, as well as the dysregulated hormonal pathways. The presence of such cells in the peritoneal cavity and what leads to the development of endometriosis is a complex process with a large number of interconnected factors, potentially both inherited and acquired. Genetic predisposition is complex and related to the combined action of several genes with limited influence. The epigenetic mechanisms control many of the processes involved in the immunologic, immunohistochemical, histological, and biological aberrations that characterize the eutopic and ectopic endometrium in affected patients. However, what triggers such alterations is not clear and may be both genetically and epigenetically inherited, or it may be acquired by the particular combination of several elements such as the persistent peritoneal menstrual reflux as well as exogenous factors. The heterogeneity of endometriosis and the different contexts in which it develops suggest that a single etiopathogenetic model is not sufficient to explain its complex pathobiology.

Differential microRNA expression between decidual and peripheral blood natural killer cells in early pregnancy

STUDY QUESTION

Have decidual natural killer (dNK) cells a different microRNA (miRNA or miR) expression pattern compared to NK cells circulating in the peripheral blood (pb) of healthy pregnant women in the first trimester of gestation?

SUMMARY ANSWER

dNK cells have a unique miRNA profile, showing exclusive expression of a set of miRNAs and significant up- or down-regulation of most of the miRNAs shared with pbNK cells.

WHAT IS KNOWN ALREADY

dNK cells differ from pbNK cells both phenotypically and functionally, and their origin is still debated. Many studies have indicated that miRNAs regulate several important aspects of NK cell biology, such as development, activation and effector functions.

STUDY DESIGN, SIZE, DURATION

Decidua basalis and peripheral blood specimens were collected from women (n = 7) undergoing voluntary termination of gestation in the first trimester of pregnancy. dNK and pbNK cells were then highly purified by cell sorting.

PARTICIPANTS/MATERIALS, SETTING, METHODS

miRNAs expression was analysed by quantitative RT-PCR (qRT-PCR)-based arrays using RNA purified from freshly isolated and highly purified pbNK and dNK cells. Results from arrays were validated by qRT-PCR assays. The bioinformatics tool ingenuity pathway analysis (IPA) was applied to determine the cellular network targeted by validated miRNAs and the correlated biological functions.

MAIN RESULTS AND THE ROLE OF CHANCE

Herein, we identified the most differentially expressed miRNAs in NK cells isolated from peripheral blood and uterine decidua of pregnant women. We found that 36 miRNAs were expressed only in dNK cells and two miRNAs only in pbNK cells. Moreover, 48 miRNAs were commonly expressed by both NK cell preparations although at different levels: 28 were upregulated in dNK cells, while 15 were downregulated compared to pbNK cells. Validation of a selected set (n = 11) of these miRNAs confirmed the differential expression of nine miRNAs: miR-10b and miR-214 expressed only in dNK cells and miR-200a-3p expressed only in pbNK cells; miR-130b-3p, miR-125a-5p, miR-212-3p and miR-454 were upregulated while miR-210-3p and miR-132 were downregulated in dNK cells compared to pbNK cells. IPA network analysis identified a single network connecting all the miRNAs as well as their significant involvement in several classes of functions: 'Organismal injury, Reproductive system disease, Inflammatory disease' and 'Cellular development'. These miRNAs target molecules such as argonaute 2, tumour protein p53, insulin and other genes that belong to the same network and significantly influence cell differentiation and pregnancy.

LIMITATIONS, REASONS FOR CAUTION

In the present study, the cellular network and biological functions modulated by miRNAs differentially expressed in dNK and pbNK cells were identified by IPA considering only molecules and relationships that were with confidence 'experimentally observed' in leucocytes. The decidual and pbNK cells that were analysed here are a heterogeneous population and further study will help to disentangle whether there are differences in miRNA production by the different subsets of NK cells.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study describing a different miRNA expression profile in dNK cells compared to matched pbNK cells during the first trimester of pregnancy. Our findings improved the body of knowledge on dNK cell biology and strongly suggest further investigation into the roles of miRNAs that are differentially expressed in human dNK compared to pbNK cells. Our results suggest that specific miRNAs can modulate dNK cell origin and functions, highlighting a potential role of this miRNA signature in human development and diseases.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from the Istituto Pasteur, Fondazione Cenci Bolognetti, the European NoE EMBIC within FP6 (Contract number LSHN-CT-2004-512040), Istituto Italiano di Tecnologia, and Ministero dell'Istruzione, dell'Università e della Ricerca (Ricerche Universitarie), and from Università Politecnica delle Marche. There are no conflicts of interest to declare.

MicroRNA Biogenesis Machinery Is Dysregulated in the Endometrium of Infertile Women Suggesting a Role in Receptivity and Infertility

MicroRNAs (miRs) regulate endometrial function and their dysregulation could underlie unexplained infertility in women. Ribonucleases including DICER and DROSHA, and the proteins, ARGONAUTE 1 (AGO 1) and 2 (AGO 2) regulate the biogenesis/maturation of miRs. We aimed to elucidate the expression and localization of miR biogenesis machinery components during the human menstrual cycle and compare their levels in endometrium from women with normal fertility and primary unexplained infertility. miR biogenesis components were measured by quantitative-RT-PCR and immunohistochemistry. In the endometrium of women with normal fertility, DROSHA immunolocalized maximally to the epithelium during the early and mid-secretory phases compared with the proliferative and late-secretory phases. Stromal DICER immunostaining intensity was higher in the late-secretory phase compared with all other phases in fertile women. DROSHA mRNA was reduced in the mid-secretory-infertile whole endometrial tissue (has all cells of the tissue), and primary epithelial and stromal cells while no differences were found in DICER, AGO1, and AGO2 mRNA. In the luminal epithelium, DROSHA staining intensity was reduced in early and mid-secretory-infertile while DICER staining was reduced in the early secretory-infertile compared with their respective fertile groups. DICER and DROSHA were dynamically regulated across the menstrual cycle and reduced levels during receptivity phase could underlie implantation failure/infertility.

Circulating miRNAs as Biomarkers for Endometriosis and Endometriosis-Related Ovarian Cancer-An Overview

Early detection and accurate diagnosis are pivotal in the management of endometriosis and endometriosis-related ovarian neoplasms (ERONs), yet there is no clear common ground regarding their pathogenesis. Endometriosis is a debilitating pathology that profoundly impairs the quality of life. Although the spontaneous resolution of endometriosis is possible, studies suggest that it can be a progressive condition, and ERONs can develop. The gold standard for diagnosis remains as the invasive method of laparoscopy followed by histological confirmation. In recent years, novel biomarkers have been discovered. MicroRNAs (miRNA) represent important epigenetic modulators of gene expression and are very attractive as biomarkers due to their lower complexity, tissue specificity, and stability in bodily fluids. Several studies have advanced the possibility of miRNAs becoming potential biomarkers in endometriosis and ERONs. Our aim is to bring these studies together in order to have a better understanding of whether, how, and when miRNAs might be used as biomarkers for these pathologies.

METHODS

We selected the reviewed papers from Google Academic, PubMed, and CrossRef. A total of eight studies met the inclusion criteria.

RESULTS

MiR-200 family, miR-143, 145, miR-20a, and miR199a were the most commonly dysregulated miRNAs in endometriosis, and miR-200 family was found to be dysregulated in both ERONs and endometriosis.

CONCLUSIONS

No single miRNA was considered as a sole biomarker for this pathology. However, since the prognostic value of biomarkers is generally enhanced if more are assessed at the same time, a panel of miRNAs could be a better indicator of the disease.

Acute Weight Loss Restores Dysregulated Circulating MicroRNAs in Individuals Who Are Obese

CONTEXT

Obesity is a global epidemic and an independent risk factor for several diseases. miRNAs are gaining interest as early molecular regulators of various pathological processes.

OBJECTIVE

To examine the miRNA signatures in women who are obese and determine the response of miRNAs to acute weight loss.

METHODS

Plasma samples were collected from women who are obese (n = 80) before and after acute weight loss (mean, 7.2%). Plasma samples from age-matched lean volunteers (n = 80) were used as controls. Total RNA was extracted from the plasma samples and subjected to NanoString analysis of 822 miRNAs. The expression level of candidate miRNAs was validated in all participants using quantitative real-time PCR analysis.

RESULTS

NanoString analysis identified substantial dysregulation of 21 miRNAs in women who are obese that were associated with impaired glucose tolerance, senescence, cardiac hypertrophy, angiogenesis, inflammation, and cell death. Acute weight loss reversed the expression pattern of 18 of these miRNAs toward those seen in the lean control group. Furthermore, real-time PCR validation of all the samples for 13 miRNAs with at least twofold upregulation or downregulation confirmed substantial dysregulation of all the chosen miRNAs in women who are obese at baseline. After acute weight loss, the levels of seven miRNAs in women who are obese and who are lean were comparable, with no statistically significant evidence for differences between the two groups.

CONCLUSIONS

Our study has provided evidence that the circulating miRNAs associated with various disorders are dysregulated in women who are obese. We also found that seven of these miRNAs showed levels comparable to those in lean controls after acute weight loss in women who are obese.

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.

Non-Coding RNAs in Endometrial Physiopathology

The Human Genome Project led to the discovery that about 80% of our DNA is transcribed in RNA molecules. Only 2% of the human genome is translated into proteins, the rest mostly produces molecules called non-coding RNAs, which are a heterogeneous class of RNAs involved in different steps of gene regulation. They have been classified, according to their length, into small non-coding RNAs and long non-coding RNAs, or to their function, into housekeeping non-coding RNAs and regulatory non-coding RNAs. Their involvement has been widely demonstrated in all cellular processes, as well as their dysregulation in human pathologies. In this review, we discuss the function of non-coding RNAs in endometrial physiology, analysing their involvement in embryo implantation. Moreover, we explore their role in endometrial pathologies such as endometrial cancer, endometriosis and chronic endometritis.

A Review of the Epigenetic Contributions to Endometriosis

Epigenetic influences have been postulated to affect the course of endometriosis. DNA methyltransferases, estrogen and progesterone receptors, micro-RNAs, and histone deacetylators, have shown differential expression in endometriosis compared with normal endometrium. Others such as aromatase, Steroid Factor-1, COX-2, and Homeobox A10 also have epigenetic modifications in endometriosis. Limitations in this area of research include heterogeneity in study design, patient populations, and methods of analysis. Larger, controlled studies are needed. Future targeted uses of this work may include using methylomes to noninvasively diagnose endometriosis, or targeting histone-deacetylase inhibitors for treatment.

Increased Expression of NDRG3 in Mouse Uterus During Embryo Implantation and in Mouse Endometrial Stromal Cells During In Vitro Decidualization

Decidualization is an indispensable event in the embryo implantation process, but its underlying molecular mechanisms remain elusive. In this study, we showed that in mice, the uterine expression of N-myc downstream-regulated gene 3 (NDRG3), a member of the α/β hydrolase superfamily, was induced by estradiol and progesterone. During the embryo implantation process, uterine Ndrg3 expression was remarkably upregulated, and its expression level at implantation sites (IS) was significantly higher than that at inter-IS. Increased uterine expression of Ndrg3 was associated with artificial decidualization and the activation of delayed implantation. The in vitro decidualization of mouse endometrial stromal cells (ESCs) induced by estradiol and progesterone was also accompanied by increased Ndrg3 expression, and downregulated Ndrg3 expression in ESCs effectively inhibited decidualization. miR-290b-5p was identified as an upstream regulator of Ndrg3, and the uterine expression level of miR-290b-5p was decreased during the implantation process. Furthermore, overexpression of miR-290b-5p in mouse ESCs inhibited their in vitro decidualization. Taken together, these data suggested that Ndrg3 might play an important role in embryo implantation by regulating decidualization potentially via the estrogen/progesterone/miR-290b-5p pathway.

miR-3074-5p Promotes the Apoptosis but Inhibits the Invasiveness of Human Extravillous Trophoblast-Derived HTR8/SVneo Cells In Vitro

OBJECTIVE

The objective of this study was to observe the effects of the overexpression of miR-3074-5p in human trophoblast cells in vitro.

DESIGN

Experimental in vitro study in HTR8/SVneo cells.

METHODS

HTR8/SVneo cells were transfected with miR-3074-5p mimic. The cell apoptosis and invasion were measured via flow cytometry and transwell assay, respectively. The expression levels of P53, Cyclin Dependent Kinase Inhibitor 1B (P27), BCL-2, BCL2 associated X (BAX), and BCL2 like 14 (BCL-G) in HTR8/SVneo cells were determined by Western blot. The alterations in gene expression profile of HTR8/SVneo cells were evaluated by complementary DNA microarray assay, and the differential expressions of dihydrolipoamide S-succinyltransferase (DLST), growth-associated protein 43 (GAP43), runt-related transcription factor 2 (RUNX2), and C-C type chemokine receptor 3 (CCR3) were validated by Western blot. Biofunctions of these differentially expressed genes were enriched by Gene Ontology analysis.

RESULTS

The overexpression of miR-3074-5p in HTR8/SVneo cells promoted cell apoptosis but inhibited cell invasion, being accompanied by the significantly elevated expressions of P27, BCL-2, and BCL-G. Meanwhile, an increased expression of P27 and P57 was also detected in a small sample size of placental villi of recurrent miscarriage (RM) patients. Totally, 411 genes and 397 genes were screened out, respectively, to be downregulated or upregulated at least by 2-folds in miR-3074-5p overexpressed HTR8/SVneo cells. These differentially expressed genes were involved in several important functions related to pregnancy. Subsequently, the reduced expressions of DLST and GAP43 proteins, as well as the increased expressions of CCR3 and RUNX2 proteins, were validated in miR-3074-5p overexpressed HTR8/SVneo cells.

CONCLUSION

These data suggested a potential contribution of miR-3074-5p in the pathogenesis of RM by disturbing the normal activities of trophoblast cells.

Biomarkers in endometriosis: challenges and opportunities

Endometriosis is a debilitating gynecologic disease affecting millions of women across the world, with symptoms including dysmenorrhea, chronic pelvic pain, and infertility. Theorized to stem from the phenomenon of retrograde menstruation, the diagnosis of endometriosis is typically delayed by 8-10 years owing to misinterpretation of symptoms as common menstrual cramps in adolescent girls and young women. With increased incidence of endometriosis in young girls correlated with earlier menarche, the development of diagnostic biomarkers is imperative for diagnosing and treating women afflicted with endometriosis as early as we can. In the past few years, multiple reviews highlighted the list of potential diagnostic candidates in peritoneal fluid, blood, urine, and endometrial biopsies from endometriosis patients in different stages of disease and menstrual cycle. In this review, we explore the opportunities and challenges facing the field of diagnostic biomarkers for endometriosis. We highlight the importance of eutopic endometrium as a source of potential diagnostic biomarkers by looking at the expression levels of noncoding RNA in tissue as well as in blood. Finally, we discuss some of the challenges that hinder our efforts in validating candidate diagnostic biomarkers for endometriosis.

Microvesicles secreted from equine amniotic-derived cells and their potential role in reducing inflammation in endometrial cells in an in-vitro model

Background

It is known that a paracrine mechanism exists between mesenchymal stem cells and target cells. This process may involve microvesicles (MVs) as an integral component of cell-to-cell communication.

Methods

In this context, this study aims to understand the efficacy of MVs in in-vitro endometrial stressed cells in view of potential healing in in-vivo studies. For this purpose, the presence and type of MVs secreted by amniotic mesenchymal stem cells (AMCs) were investigated and the response of endometrial cells to MVs was studied using a dose-response curve at different concentrations and times. Moreover, the ability of MVs to counteract the in vitro stress in endometrial cells induced by lipopolysaccharide was studied by measuring the rate of apoptosis and cell proliferation, the expression of some pro-inflammatory genes such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin 1β (IL-1β), and metalloproteinases (MMP) 1 and 13, and the release of some pro- or anti-inflammatory cytokines.

Results

MVs secreted by the AMCs ranged in size from 100 to 200 nm. The incorporation of MVs was gradual over time and peaked at 72 h. MVs reduced the apoptosis rate, increased cell proliferation values, downregulated pro-inflammatory gene expression, and decreased the secretion of pro-inflammatory cytokines.

Conclusion

Our data suggest that some microRNAs could contribute to counteracting in-vivo inflammation of endometrial tissue.

Fertile ground: human endometrial programming and lessons in health and disease

The human endometrium is a highly dynamic tissue that is cyclically shed, repaired, regenerated and remodelled, primarily under the orchestration of oestrogen and progesterone, in preparation for embryo implantation. Humans are among the very few species that menstruate and that, consequently, are equipped with unique cellular and molecular mechanisms controlling these cyclic processes. Many reproductive pathologies are specific to menstruating species, and studies in animal models rarely translate to humans. Abnormal remodelling and regeneration of the human endometrium leads to a range of reproductive complications. Furthermore, the processes regulating endometrial remodelling and implantation, including those controlling hormonal impact, breakdown and repair, stem/progenitor cell activation, inflammation and cell invasion have broad applications to other fields. This Review presents current knowledge regarding the normal and abnormal function of the human endometrium. The development of biomarkers for prediction of uterine diseases and pregnancy disorders and future avenues of investigation to improve fertility and enhance endometrial function are also discussed.

Deep-sequencing identification of differentially expressed miRNAs in decidua and villus of recurrent miscarriage patients

PURPOSE

MicroRNAs (miRNAs) are small non-coding RNA molecules that play critical roles in post-transcriptional gene expression regulation. The aim of this study was to identify differentially expressed miRNAs in decidua and villus of recurrent miscarriage (RM) patients.

METHODS

Participants were recruited at the outpatient Department of Gynecology and Obstetrics, The Second Hospital of Tianjin Medical University, China. Decidua and villus tissues were collected by curettage from recruited RM patients and normal pregnant women with their informed consent. MiRNAs expression profiles in decidua or villus were respectively determined by the deep-sequencing analysis. The predicated target genes of these differentially expressed miRNAs were analyzed by miRWalk. The differential expressions of four miRNAs in decidua and four miRNAs in villus between the six pairs of RM patients and normal pregnant women were confirmed by qRT-PCR analysis. The expression patterns of two predicated target genes, Bcl-2 and Pten, in the same six pairs of decidual or villus tissues were detected by Western blotting analysis, respectively.

RESULTS

Totally 18 RM patients and 15 normal pregnant women were recruited. Thirty-two miRNAs in decidua and four miRNAs in villus of RM patients were screened out to be significantly up-regulated compared to that of normal pregnant women, and five miRNAs in villus of RM patients were screened out to be remarkably down-regulated compared to that of normal pregnant women (P value < 0.05 and Fold change >2). These differentially expressed miRNAs were predicted to target a large number of genes that involved in cell apoptosis, p53 signaling pathway, cell cycle and other cellular bio-functions. Differential expressions of hsa-miR-516a-5p, -517a-3p, -519a-3p and -519d in decidua, as well as hsa-miR-1, -372, -100-5p and -146a-5p in villus, were validated by qRT-PCR analysis. In the decidual of RM patients, expression of hsa-miR-516a-5p, -517a-3p, -519a-3p and -519d were significantly up-regulated compared to normal pregnancy. In the villi of RM patients, expression of hsa-miR-100 and -146a-5p were significantly higher, while hsa-miR-1 and -372 were significantly lower compared to normal pregnancy. Furthermore, the expression of Bcl-2 and Pten, a predicated target gene of hsa-miR-1 or hsa-miR-372 respectively, was significantly up-regulated in the villi of RM patients.

CONCLUSIONS

These data suggested that the pathogenic process of RM might be associated with the alteration of miRNAs expression profiles in decidua and villus. Especially, the aberrant placental expression of hsa-miR-1 and -372 might be involved in the progression of RM, but need to be further investigated by larger studies in the future.

Understanding and improving endometrial receptivity

PURPOSE OF THE REVIEW

For a successful pregnancy, the synchronic coordination between the embryonic development and the endometrial status is crucial. The endometrium is a hormonally regulated organ that is nonadhesive to embryos throughout most of the menstrual cycle in humans. Endometrial receptivity refers to a hormone-limited period in which the endometrial tissue acquires a functional and transient ovarian steroid-dependent status allowing blastocyst implantation and therefore pregnancy initiation.

RECENT FINDINGS

Our group has developed the endometrial receptivity array (ERA), a customized array based on the expression of 238 genes coupled to a computational predictor capable of diagnosing a functionally receptive endometrium regardless of its histological appearance. Clinical results obtained in our laboratory demonstrate the diagnostic and therapeutic efficiency of the ERA test in patients with implantation failure, allowing the personalization of the optimal day for embryo transfer.

SUMMARY

To keep improving the global knowledge of endometrial receptivity stage, new high-throughput techniques like RNA-seq or genome-wide association studies will be crucial in the near future. Also the identification of new biomarkers of endometrial receptivity that could be assessed by noninvasive methods has become a challenging goal to help diagnose the endometrial status to increase implantation rates and pregnancy outcomes in patients undergoing assisted reproductive treatments.

Omics in Reproductive Medicine: Application of Novel Technologies to Improve the IVF Success Rate

Treatment for many infertile couples often consists of in vitro fertilization (IVF) but an estimated 70% of IVF cycles fail to produce a live birth. In an attempt to improve the live birth rate, the vast majority of IVF cycles performed in the United States involve the transfer of multiple embryos, a practice that increases the risk of multiple gestation pregnancy. This is a concern because multiple gestation pregnancies are associated with an increased incidence of maternal and fetal complications and significant cost associated with the care of preterm infants. As the ideal outcome of each IVF cycle is the birth of a single healthy baby, significant effort has focused on identifying embryos with the greatest developmental potential. To date, selection of euploid embryos using comprehensive chromosome screening (CCS) is the most promising approach while metabolomic and proteomic assessment of spent culture medium have the potential to noninvasively assess embryo viability. Endometrial gene expression profiling may help determine the optimal time to perform embryo transfer. While CCS has been implemented in some clinics, further development and optimization will be required before analysis of spent culture medium and endometrial gene expression profiling make the transition to clinical use. This review will describe efforts to identify embryos with the greatest potential to result in a healthy, live birth, with a particular emphasis on detection of embryo aneuploidy and metabolic profiling of spent embryo culture medium. Assessment of endometrial receptivity to identify the optimal time to perform embryo transfer will also be discussed.

MicroRNA-212 Regulates the Expression of Olfactomedin 1 and C-Terminal Binding Protein 1 in Human Endometrial Epithelial Cells to Enhance Spheroid Attachment In Vitro

Successful embryo implantation requires a synchronized dialogue between a competent blastocyst and the receptive endometrium, which occurs in a limited time period known as the "window of implantation." Recent studies suggested that down-regulation of olfactomedin 1 (OLFM1) in the endometrium and fallopian tube is associated with receptive endometrium and tubal ectopic pregnancy in humans. Interestingly, the human chorionic gonadotropin (hCG) induces miR-212 expression, which modulates OLFM1 and C-terminal binding protein 1 (CTBP1) expressions in mouse granulosa cells. Therefore, we hypothesized that embryo-derived hCG would increase miR-212 expression and down-regulate OLFM1 and CTBP1 expressions to favor embryo attachment onto the female reproductive tract. We found that hCG stimulated the expression of miR-212 and down-regulated OLFM1 but not CTBP1 mRNA in both human endometrial (Ishikawa) and fallopian (OE-E6/E7) epithelial cells. However, hCG suppressed the expression of OLFM1 and CTBP1 proteins in both cell lines. The 3'UTR of both OLFM1 and CTBP1 contained binding sites for miR-212. The miR-212 precursor suppressed luciferase expression, whereas the miR-212 inhibitor stimulated luciferase expression of the wild-type (WT)-OLFM1 and WT-CTBP1 reporter constructs. Furthermore, hCG (25 IU/ml) treatments stimulated trophoblastic (Jeg-3) spheroid (blastocyst surrogate) attachment onto Ishikawa and OE-E6/E7 cells. Transfection of miR-212 precursor increased Jeg-3 spheroid attachment onto Ishikawa cells and decreased OLFM1 and CTBP1 protein expressions, whereas the opposite occurred with miR-212 inhibitor. Taken together, hCG stimulated miR-212, which in turn down-regulated OLFM1 and CTBP1 expression in fallopian and endometrial epithelial cells to favor spheroid attachment.

Altered expression of microRNA-451 in eutopic endometrium of baboons (Papio anubis) with endometriosis

STUDY QUESTION

Are microRNAs (miRs) altered in the eutopic endometrium (EuE) of baboons following the induction of endometriosis?

SUMMARY ANSWER

Induction of endometriosis causes significant changes in the expression of eight miRs, including miR-451, in the baboon endometrium as early as 3 months following induction of the disease.

WHAT IS KNOWN ALREADY

Endometriosis is one of the most common gynecological disorders and causes chronic pelvic pain and infertility in women of reproductive age. Altered expression of miRs has been reported in women and has been suggested to play an important role in the pathophysiology of several gynecological disorders including endometriosis.

STUDY DESIGN, SIZE, DURATION

EuE was obtained from the same group of baboons before and 3 months after the induction of endometriosis. The altered expression of miR-451 was validated in the eutopic and ectopic endometrium of additional baboons between 3 and 15 months following disease induction. Timed endometrial biopsies from women with and without endometriosis were also used to validate the expression of miR-451.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Total RNA was extracted from EuE samples before and after the induction of endometriosis, and miRNA expression was analyzed using a 8 × 15 K miR microarray. Microarray signal data were preprocessed by AgiMiRna software, and an empirical Bayes model was used to estimate the changes. The present study focused on quantitative RT-PCR validation of the microarray data, specifically on miR-451 and its target genes in both baboons (n = 3) and women [control (n = 7) and endometriosis (n = 19)]. Descriptive and correlative analysis of miR-451 and target gene expression was conducted using in situ hybridization and immunohistochemistry, while functional analysis utilized an in vitro 3' untranslated region (UTR) luciferase assay and overexpression of miR-451 in human endometrial and endometriotic cell lines.

MAIN RESULTS AND THE ROLE OF CHANCE

Induction of endometriosis results in the altered expression of miR-451, -141, -29c, -21, -424, -19b, -200a and -181a in the baboon endometrium. In the baboon, induction of endometriosis significantly decreased the expression of miR-451 at 3 months (P < 0.001), which was also associated with increased expression of its target gene YWHAZ (14.3.3ζ). A similar significant (P < 0.0001) decrease in miR-451 expression was observed in women with endometriosis. The 3' UTR luciferase assay confirmed the regulation of YWHAZ expression by miR-451. Furthermore, overexpression of miR-451 in 12Z cells (immortalized human endometriotic epithelial cell line) led to the decreased expression of its target YWHAZ and this was correlated with decreased cell proliferation.

LIMITATIONS, REASONS FOR CAUTION

The study focused only on miR-451 and one of its targets, namely YWHAZ. A single miR could target number of genes and a single gene could also be regulated by number of miRs; hence, it is possible that other miRs and their regulated genes may contribute to the pathophysiology of endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Our data suggest that the presence of ectopic lesions in baboon causes changes in EuE miR expression as early as 3 months postinduction of the disease, and some of these changes may persist throughout the course of the disease. We propose that the marked down-regulation of miR-451 in both baboons and women with endometriosis increases the expression of multiple target genes. Increased expression of one of the target genes, YWHAZ, increases proliferation, likely contributing to the pathophysiology of the disease.

Potential role of cervicovaginal extracellular particles in diagnosis of endometriosis

Background

Macaques are an excellent model for many human diseases, including reproductive diseases such as endometriosis. A long-recognized need for early biomarkers of endometriosis has not yet resulted in consensus. While biomarker studies have examined many bodily fluids and targets, cervicovaginal secretions have been relatively under-investigated. Extracellular vesicles (EVs, including exosomes and microvesicles) are found in every biofluid examined, carry cargo including proteins and RNA, and may participate in intercellular signaling. Little is known about EVs in the cervicovaginal compartment, including the effects of reproductive tract disease on quantity and quality of EVs.

Case presentation

In September 2014, a 9-year-old rhesus macaque was diagnosed with endometriosis at The Johns Hopkins University School of Medicine. Ultrasound-guided fine needle aspiration of a cyst and subsequent laparotomy confirmed diagnosis. The animal was sent to necropsy following euthanasia for humane reasons. Perimortem vaginal swabs and cervicovaginal lavages were obtained. Using a combination of methods, including ultracentrifugation and NanoSight visualization technology, approximate numbers of EVs from each sample were calculated and compared to populations of EVs from other, reproductively normal macaques. Fewer EVs were recovered from the endometriosis samples as compared with those from reproductively healthy individuals.

Conclusion

To our knowledge, this is the first examination of EVs in primate cervicovaginal secretions, including those of a macaque with endometriosis. This case study suggests that additional research is justified to determine whether quantification of EVs—or their molecular cargo—in cervicovaginal lavage and vaginal swabs may provide a novel, relatively non-invasive diagnostic for primate endometrial disease or other reproductive tract diseases.

Aberrant Placental Villus Expression of miR-486-3p and miR-3074-5p in Recurrent Miscarriage Patients and Uterine Expression of These MicroRNAs during Early Pregnancy in Mice

MicroRNAs (miRNAs) are critical regulators of gene expression; they have emerged as new players in the pathophysiology of reproductive disorders such as preeclampsia and recurrent miscarriage (RM). In this study, miRNA expression profiles were determined by deep sequencing analysis in placental villi obtained from women with RM and with gestational age-matched normal pregnancy (NP). A total of 69 miRNAs were found to be aberrantly expressed in RM. Five of these human (Homo sapiens) miRNAs (hsa-miRNAs), including hsa-miR-3074-5p, -486-3p, -1269b, -6765-3p and -144-3p, were validated by qRT-PCR in 12 RM and 10 NP placental villi. Hsa-miR-3074-5p expression was significantly higher, while hsa-miR-486-3p expression was significantly lower, in RM compared to NP. Subsequently, the expression of mouse (Mus musculus) miR-486-3p (mmu-miR-486-3p) and mmu-miR-3074-5p, which are identical to hsa-miR-486-3p and hsa-miR-3074-5p, respectively, were examined by qRT-PCR in the uterus during early pregnancy. Mmu-miR-486-3p expression was significantly increased during the peri-implantation period, and the levels were significantly higher at implantation than at non-implantation sites. In contrast, the expression of mmu-miR-3074-5p was markedly decreased at implantation compared to non-implantation sites. These data suggest that miR-486-3p and miR-3074-5p may be involved in embryo implantation and that their aberrant expression is associated with RM. Larger studies are warranted to follow up this pilot study. © 2015 S. Karger AG, Basel.

Use of miRNAs as biomarkers in sepsis

Sepsis is one of the most common causes of death in critical patients. Severe generalized inflammation, infections, and severe physiological imbalances significantly decrease the survival rate with more than 50%. Moreover, monitoring, evaluation, and therapy management often become extremely difficult for the clinician in this type of patients. Current methods of diagnosing sepsis vary based especially on the determination of biochemical-humoral markers, such as cytokines, components of the complement, and proinflammatory and anti-inflammatory compounds. Recent studies highlight the use of new biomarkers for sepsis, namely, miRNAs. miRNAs belong to a class of small, noncoding RNAs with an approximate content of 19-23 nucleotides. Following biochemical and physiological imbalances, the expression of miRNAs in blood or other body fluids changes significantly. Moreover, its stability, specificity, and selectivity make miRNAs ideal candidates for sepsis biomarkers. In conclusion, we can affirm that stable species of circulating miRNAs represent potential biomarkers for monitoring the evolution of sepsis.

Inhibition of Endometrial Tiam1/Rac1 Signals Induced by miR-22 Up-Regulation Leads to the Failure of Embryo Implantation During the Implantation Window in Pregnant Mice

This study assessed first the impact of endometrial Tiam1/Rac1 signals and microRNA-22 (miR-22) on embryo implantation in mice, and then the expression of the above three genes in the endometrium during the embryo implantation window in the natural menstrual cycle in women with repeated implantation failure (RIF) after in vitro fertilization treatment. Four hundred fifty-two Kun-ming female mice and 200 women (70 infertility patients with RIF, 130 women as controls) were entered into this study. Endometrial Tiam1/Rac1 signals and miR-22 expression were studied in clinical and mouse samples and serum estrogen (E2) and progesterone (P) were analyzed in clinical subjects. A pregnant mouse model based on an endometrial miR-22 and Tiam1 mRNA expression trend of patients with RIF was constructed and then the embryo implantation numbers were analyzed, and an ovariectomized mouse model was used to assess correlations of expression of these three genes with E2 and P. The results showed that during the embryo implantation window in the natural menstrual cycle, endometrial miR-22 was significantly higher whereas Tiam1/Rac1 signals were notably lower in patients with RIF than in controls, and the P:E2 ratio was statistically lower in the RIF group. Tiam1/Rac1 signal down-regulation and miR-22 up-regulation contributed to the inhibition of embryo implantation in mice. We also found a suppressive effect of miR-22 up-regulation on Tiam1/Rac1 signal expression, and reciprocal regulation of E2 and P for these three genes' expression in mice. In conclusion, miR-22 up-regulation and Tiam1/Rac1 signal down-regulation inhibited embryo implantation in mice; this mechanism may be partially due to the suppressive effect of miR-22 on Tiam1 expression, and is regulated to some extent by serum E2 and P. Our findings provide evidence that endometrial Tiam1/Rac1 signal down-regulation along with miR-22 up-regulation during embryo implantation window in the natural menstrual cycle may be one of the reasons for the failure of embryo implantation in patients with RIF.

Altered levels of circulating miRNAs are associated Schistosoma japonicum infection in mice

Background

Dioecious flatworms of the genus Schistosoma causes schistosomiasis, which is a major public health problem in developing countries. Acquiring detailed knowledge of schistosome-host interactions may aid in the development of novel strategies for schistosomiasis control. MicroRNAs (miRNAs) are involved in processes such as development, cell proliferation, metabolism, and signal transduction. Circulating miRNAs not only serve as a novel class of biomarkers of many diseases but also regulate target gene expression in recipient cells, which are similar to hormones.

Methods

In the present study, we used miRNA microarrays to determine the profile of circulating miRNAs associated with S. japonicum infection of mice. The biological functions of the altered levels of miRNAs and their target genes were predicted using bioinformatics. Expression levels of selected miRNAs and their target genes were further analyzed by quantitative RT-PCR.

Results

Our study identified 294 and 189 miRNAs in infected mice that were expressed in two independent experiments at levels ≥ 2-fold higher or ≤ 0.5-fold lower, respectively, compared with uninfected mice. Thirty-six of the same miRNAs were detected in these analyses. Moreover, pathway analyses indicated that most of these miRNAs are putatively involved in signaling pathways associated with pathogenesis, such as Wnt and MAPK signaling. Further, we show an inverse correlation between the circulating levels of these miRNAs and their target genes, suggesting that changes in miRNA expression may cause aberrant expression of genes such as Creb1 and Caspase-3 in mice infected with S. japonicum.

Conclusions

Our study shows significant differences in the levels of circulating miRNAs between S. japonicum infected mice and uninfected mice. In particular, the altered levels of miR-706 and miR-134-5p were associated with altered levels of expression of the Caspase-3 and Creb1 genes, respectively, suggesting that circulating miRNAs may serve as important mediators of the pathology of hepatic schistosomiasis. Additionally, our results are expected to provide new insights for further understanding the mechanisms of schistosome-host interaction that may facilitate in the development of novel interventions for alleviating the symptom of S. japonicum infection as well as for preventing and treating schistosomiasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-0806-5) contains supplementary material, which is available to authorized users.

MicroRNA and gynecological reproductive diseases

MicroRNAs (miRNAs) are a class of small non-coding RNAs estimated to regulate the translation of mRNAs in 30% of all genes in animals by inhibiting translation. Aberrant miRNA expression is associated with many human diseases, including gynecological diseases, cancer, inflammatory diseases, and cardiovascular disorders. Abnormal expression of miRNAs has been observed in multiple human reproductive tract diseases including preeclampsia, endometrioid endometrial adenocarcinoma, uterine leiomyomata, ovarian carcinoma, endometriosis, and recurrent pregnancy loss. In the following review, an update of the role of microRNA and gynecological diseases is performed covering, not only impact of microRNA dysregulation in the origin of each disease, but also showing the potential useful diagnostic and therapeutic tool that miRNA may play in these gynecological pathologies.