HOXA10, EMX2 and TENM1 expression in the mid-secretory endometrium of infertile women with a Müllerian duct anomaly

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.

The effect of hysteroscopic metroplasty on fertility in T-shaped and Y-shaped dysmorphic uterus

OBJECTIVE

T/Y-shaped dysmorphic uterus is frequently associated with subfertility, abortion, preterm delivery, and recurrent implantation failure. In this study, the impact of hysteroscopic metroplasty for a T/Y-shaped uterus on obstetric outcomes was investigated in patients with infertility and recurrent pregnancy loss (RPL) and compared the uterine anomaly subgroups.

METHOD

Cases with infertility and/or RPL diagnosed with T/Y-shaped uterus by hysterosalpingography (HSG) and 3D transvaginal ultrasonography (3D TVUSG) with no other male or female pathology have recruited the study. Medical history and the obstetric outcome after two years of follow-up were recorded.

RESULTS

Out of the 92 cases recruited, T-shaped uteri (Group-1) were observed in 30, while 62 (67.3%) patients had Y-shaped uteri. Pregnancy was achieved in 50 (54.3%) of the cases, 28 (56%) of the pregnancies occurred spontaneously, and in 22 (44%) pregnancy was achieved through assisted reproductive techniques (ART). Term delivery occurred in 29 (76.3%) of the pregnancies while 9 (23.6%) had preterm deliveries and a total of 38 (76%) resulted in a live birth. Out of the 31 patients with previous RPL history, 13 (41.9%) achieved pregnancy and 11 out of 13 (84.6%) had a term pregnancy followed by live birth.

CONCLUSION

Spontaneous pregnancy, and term pregnancy rates after surgery were found to be promising in these uterine anomalies. The pregnancy outcome of the primary infertile patients was found the same in two groups (50%-46.1%), but the results of the RPL patients were found to be better in the T-shaped group than in the Y-shaped group (70%-28.5%).

An Association between EMX2 Variations and Mayer-Rokitansky-Küster-Hauser Syndrome: A Case-Control Study of Chinese Women

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by congenital malformations of Müllerian structures, including the uterus and upper two-thirds of the vagina in women. Until now, the etiology of this disease has remained unknown. We hypothesized that EMX2 (the human homologue of Drosophila empty spiracles gene (2) might be a candidate gene for MRKH syndrome because it plays an important role in the development of the urogenital system. Through sequence analysis of EMX2 in forty patients with MRKH syndrome and one hundred and forty healthy women controls, we identified eleven variations in total. Four novel variations were only found in MRKH patients, and seven single nucleotide polymorphisms were identified in both patients and controls. In silico analyses suggested that the novel variations in the 5'UTR (untranslated region) and 3'UTR might affect transcriptional activity of the EMX2 promoter or posttranscriptional processing. In conclusion, our study suggests an association between noncoding variations in the EMX2 gene and MRKH syndrome in a Chinese Han population.

HOXA10 improves endometrial receptivity by upregulating E-cadherin

In the endometrium of women with recurrent implantation failure (RIF) and unexplained recurrent miscarriage (RM)，the expression levels of homeobox A10 (HOXA10) and E-cadherin were positively correlated. To explore whether HOXA10 regulates E-cadherin during endometrial receptivity establishment, Ishikawa and RL95–2 cells were transfected with target-specific siRNA and overexpression plasmid of HOXA10. The expression levels of HOXA10 and E-cadherin were measured by western blot and qRT-PCR. Attachment assay of JEG-3 spheroids to endometrial cells were conducted to explore the adhesive functions after HOXA10 interfered. Chromatin immunoprecipitation assays and dual luciferase reporter were used to investigate the regulatory mechanism of HOXA10. CD1 mice were transfected with si-HOXA10 to confirm these results in vivo. In Ishikawa and RL95–2 cells, the expression of E-cadherin was positively correlated with HOXA10 when it was silenced/overexpressed. Consistently, the adhesion of endometrial epithelium cells and trophoblast cells was inhibited after HOXA10 was silenced, and exogenous restoration of E-cadherin expression reversed this effect to some extent. HOXA10 regulates the expression of E-cadherin by directly binding to a conserved motif (TGTACTAAAAA) located in the E-cadherin promoter region. In addition, after knockdown of HOXA10 in CD1 mice, both the implantation and live birth rates were decreased. In conclusion, HOXA10 can bind to the E-cadherin promoter region and directly regulate its expression, thereby improving endometrial receptivity and subsequently increasing the embryo adhesion and implantation.

Increased METTL3-mediated m6A methylation inhibits embryo implantation by repressing HOXA10 expression in recurrent implantation failure

BACKGROUND

Recurrent implantation failure (RIF) is a major limitation of assisted reproductive technology, which is associated with impaired endometrial receptivity. Although N⁶-methyladenosine (m⁶A) has been demonstrated to be involved in various biological processes, its potential role in the endometrium of women with RIF has been poorly studied.

METHODS

Global m⁶A levels and major m⁶A methyltransferases/demethylases mRNA levels in mid-secretory endometrium from normal and RIF women were examined by colorimetric m⁶A quantification strategy and quantitative real-time PCR, respectively. The effects of METTL3-mediated m⁶A modification on embryo attachment were evaluated by an vitro model of a confluent monolayer of Ishikawa cells co-cultured with BeWo spheroids, and the expression levels of homeo box A10 (HOXA10, a well-characterized marker of endometrial receptivity) and its downstream targets were evaluated by quantitative real-time PCR and Western blotting in METTL3-overexpressing Ishikawa cells. The molecular mechanism for METTL3 regulating HOXA10 expression was determined by methylated RNA immunoprecipitation assay and transcription inhibition assay.

RESULTS

Global m⁶A methylation and METTL3 expression were significantly increased in the endometrial tissues from women with RIF compared with the controls. Overexpression of METTL3 in Ishikawa cells significantly decreased the ration of BeWo spheroid attachment, and inhibited HOXA10 expression with downstream decreased β3-integrin and increased empty spiracles homeobox 2 expression. METTL3 catalyzed the m⁶A methylation of HOXA10 mRNA and contributed to its decay with shortened half-life. Enforced expression of HOXA10 in Ishikawa cells effectively rescued the impairment of METTL3 on the embryo attachment in vitro.

CONCLUSION

Increased METTL3-mediated m⁶A modification represents an adverse impact on embryo implantation by inhibiting HOXA10 expression, contributing to the pathogenesis of RIF.

Studying Müllerian duct anomalies - from cataloguing phenotypes to discovering causation

Müllerian duct anomalies (MDAs) are developmental disorders of the Müllerian duct, the embryonic anlage of most of the female reproductive tract. The prevalence of MDAs is 6.7% in the general female population and 16.7% in women who exhibit recurrent miscarriages. Individuals affected by these anomalies suffer from high rates of infertility, first-trimester pregnancy losses, premature labour, placental retention, foetal growth retardation and foetal malpresentations. The aetiology of MDAs is complex and heterogeneous, displaying a range of clinical pictures that generally lack a direct genotype-phenotype correlation. De novo and familial cases sharing the same genomic lesions have been reported. The familial cases follow an autosomal-dominant inheritance, with reduced penetrance and variable expressivity. Furthermore, few genetic factors and molecular pathways underpinning Müllerian development and dysregulations causing MDAs have been identified. The current knowledge in this field predominantly derives from loss-of-function experiments in mouse and chicken models, as well as from human genetic association studies using traditional approaches, such as microarrays and Sanger sequencing, limiting the discovery of causal factors to few genetic entities from the coding genome. In this Review, we summarise the current state of the field, discuss limitations in the number of studies and patient samples that have stalled progress, and review how the development of new technologies provides a unique opportunity to overcome these limitations. Furthermore, we discuss how these new technologies can improve functional validation of potential causative alterations in MDAs.

Summary: Here, we review the current knowledge about Müllerian duct anomalies in the context of new high-throughput technologies and model systems and their implications in the prevention of these disorders.

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.

Aberrant DNA methylation in the PAX2 promoter is associated with Müllerian duct anomalies

PURPOSE

Abnormalities during Müllerian duct and female reproductive tract formation during embryonic development result in Müllerian duct anomalies (MDA). Previous studies have identified a role for mutations in related genes and DNA copy number variation (CNV). However, the correlation between gene methylation and MDA remains to be understood.

METHODS

Endometrial tissues were collected from patients with septate (n = 23) or normal uterus (n = 28). We detected the methylation status of CpG sites and mRNA levels of nine candidate genes, including HOXA10, EMX2, TP63, ITGB3, PAX2, LHX1, GSC, WNT4, and H19, using MethyTarget and quantitative real-time polynucleotide chain reaction (qRT-PCR), respectively RESULTS: Compared with healthy controls, we detected three hypomethylated CpG sites (P < 0.05) and increased mRNA levels of PAX2 (P < 0.05) in individuals with MDA. HOXA10, EMX2, TP63, ITGB3, LHX1, and GSC had 1, 1, 2, 1, 5, and 2 differentially methylated CpG sites (P < 0.05), respectively, but there were no significant differences in their mRNA levels (P > 0.05). WNT4 and H19 did not show differences in methylation (P > 0.05) and mRNA levels (P > 0.05).

CONCLUSIONS

Aberrant DNA methylation within the promoter of PAX2 may contribute to the development of MDA by regulating its gene expression. However, the methylation status of HOXA10, EMX2, TP63, ITGB3, LHX1, GSC, WNT4, and H19, may not contribute to the development of MDA.

IVF outcomes after hysteroscopic metroplasty in patients with T- shaped uterus

Background

T- shaped uterus may be associated with infertility and adverse pregnancy outcomes. Hysteroscopic metroplasty may improve the reproductivity for these cases. To our knowledge, there is no data in literature about the clinical consequences of in vitro fertilization (IVF) in patients undergoing hysteroscopic metroplasty for T-shaped uterus. The principal objective of the current study is to assess the impact of hysteroscopic metroplasty for T-shaped uterus on the reproductive outcomes of IVF.

Methods

IVF outcomes of 74 patients who underwent hysteroscopic metroplasty for T- shaped uterus and 148 patients without any uterine abnormalities and with diagnosis of unexplained infertility (control group) were retrospectively analyzed.

Results

Patients in metroplasty and control groups were comparable with respect to age, BMI, partner’s age and duration of infertility. Number of patients with a history of pregnancy beyond 20 weeks of gestation was significantly lower in the metroplasty group (4.1% vs 18.2%; p < 0.05). Number of previous unsuccessful cycles and percentage of patients with ≥3 unsuccessful IVF cycles (35.1% vs 17.6%; p < 0.05) were significantly higher in the metroplasty group. There were no significant differences in the reproductive outcomes such as the pregnancy rate, clinical pregnancy or live birth rate between the metroplasty and control groups. There were non-significant trends for higher rates of miscarriage (18.8% vs 8%, p > 0.05) and biochemical pregnancy (20.0% vs 10.7%, p > 0.05) in the metroplasty group compared to the control group.

Conclusions

Reproductive results of the IVF cycles after hysteroscopic correction of T-shaped uterus were comparable to those of the patients without any uterine abnormalities and with diagnosis of unexplained infertility. Hysteroscopic metroplasty may contribute to improved IVF outcomes in patients with T-shaped uterus.

The pathophysiology of the septate uterus: a systematic review

BACKGROUND

Little is known about the pathophysiology underlying the increased risk for impaired reproductive outcomes in women with a septate uterus.

OBJECTIVES

We explored the available evidence on the pathophysiology of the septate uterus in an attempt to find a biological basis for these effects.

SEARCH STRATEGY

We performed a systematic literature search in OVID MEDLINE and OVID EMBASE from inception to January 2018.

SELECTION CRITERIA

We selected studies that investigated the pathophysiology of the septate uterus. Case reports or reviews without original data were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently evaluated potentially eligible papers.

MAIN RESULTS

Thirty-eight studies were included for analysis. The overall findings were that the intrauterine septum consists of endometrium and myometrium similar to the uterine wall. All five imaging studies that evaluated vascularity found that most of the intrauterine septa were vascularised. Histological studies found that the intrauterine septum consisted of myometrium and was covered by endometrium (n = 9). The endometrium covering the septum showed differences in histological composition in four studies and in gene expression in three studies compared with the normal uterine wall.

CONCLUSIONS

We found no clear biological basis for the impaired reproductive outcomes in women with a septate uterus. Either the gross anatomy of the septum itself or differences in histology or gene expression of the septum could account for the increased risk of reproductive waste observed after implantation in the septum.

TWEETABLE ABSTRACT

In women with a septate uterus differences in histology or gene expression could account for impaired reproductive outcome.

Defining the genetic profile of endometriosis

Endometriosis is a pathological condition which has been extensively studied, since its pathophysiology stems from a broad spectrum of environmental influences and genetic factors. Familial studies aim at defining inheritance trends, while linkage analysis studies focus on the identification of genetic sites related to endometriosis susceptibility. Genetic association studies take into account candidate genes and single nucleotide polymorphisms, and hence target at unraveling the association between disease severity and genetic variation. The common goal of various types of studies is, through genetic mapping methods, the timely identification of therapeutic strategies for disease symptoms, including pelvic pain and infertility, as well as efficient counselling. While genome-wide association studies (GWAS) play a primary role in depicting genetic contributions to disease development, they entail a certain bias as regards the case-control nature of their design and the reproducibility of the results. Nevertheless, genetic-oriented studies and the implementation of the results through clinical tests, hold a considerable advantage in proper disease management. In this review article, we present information about gene-gene and gene-environment interactions involved in endometriosis and discuss the effectiveness of GWAS in identitying novel potential therapeutic targets in an attempt to develop novel therapeutic strategies for a better management and treatment of patients with endometriosis.

Teneurins: An Integrative Molecular, Functional, and Biomedical Overview of Their Role in Cancer

Teneurins are large transmembrane proteins originally identified in Drosophila. Their essential role in development of the central nervous system is conserved throughout species, and evidence supports their involvement in organogenesis of additional tissues. Homophilic and heterophilic interactions between Teneurin paralogues mediate cellular adhesion in crucial processes such as neuronal pathfinding and synaptic organization. At the molecular level, Teneurins are proteolytically processed into distinct subdomains that have been implicated in extracellular and intracellular signaling, and in transcriptional regulation. Phylogenetic studies have shown a high degree of intra- and interspecies conservation of Teneurin genes. Accordingly, the occurrence of genetic variants has been associated with functional and phenotypic alterations in experimental systems, and with some inherited or sporadic conditions. Recently, tumor-related variations in Teneurin gene expression have been associated with patient survival in different cancers. Although these findings were incidental and molecular mechanisms were not addressed, they suggested a potential utility of Teneurin transcript levels as biomarkers for disease prognosis. Mutations and chromosomal alterations affecting Teneurin genes have been found occasionally in tumors, but literature remains scarce. The analysis of open-access molecular and clinical datasets derived from large oncologic cohorts provides an invaluable resource for the identification of additional somatic mutations. However, Teneurin variants have not been classified in terms of pathogenic risk and their phenotypic impact remains unknown. On this basis, is it plausible to hypothesize that Teneurins play a role in carcinogenesis? Does current evidence support a tumor suppressive or rather oncogenic function for these proteins? Here, we comprehensively discuss available literature with integration of molecular evidence retrieved from open-access databases. We show that Teneurins undergo somatic changes comparable to those of well-established cancer genes, and discuss their involvement in cancer-related signaling pathways. Current data strongly suggest a functional contribution of Teneurins to human carcinogenesis.

Expression of teneurins is associated with tumor differentiation and patient survival in ovarian cancer

Teneurins are a family of highly conserved pair-rule proteins involved in morphogenesis and development of the central nervous system. Their function in adult tissues and in disease is largely unknown. Recent evidence suggests a role for dysregulated expression of Teneurins in human tumors, but systematic investigations are missing. Here, we investigated Teneurin-2 and Teneurin-4 expression in various cancer cell lines and in ovarian tumor tissues. Teneurin-2 and Teneurin-4 were expressed in most of the breast cancer cell lines tested. Teneurin-4 was also detected in ovarian cancer cell lines, and throughout ovarian tumors and normal ovary tissue. Ovarian tumors with low Teneurin-4 expression showed less differentiated phenotypes and these patients had shorter mean overall survival. Similarly, Teneurin-2 expression correlated with overall survival as well, especially in patients with serous tumors. In the various cell lines, 5-Aza-cytidine-induced changes in DNA methylation did not alter expression of Teneurin-2 and Teneurin-4, despite the existence of predicted CpG islands in both genes. Interestingly, however, we found evidence for the control of Teneurin-2 expression by the oncogenic growth factor FGF8. Furthermore, we identified multiple transcript splicing variants for Teneurin-2 and Teneurin-4, indicating complex gene expression patterns in malignant cells. Finally, downregulation of Teneurin-4 expression using siRNA caused a cell-type dependent increase in proliferation and resistance to cisplatin. Altogether, our data suggest that low Teneurin-4 expression provides a growth advantage to cancer cells and marks an undifferentiated state characterized by increased drug resistance and clinical aggressiveness. We conclude that Teneurin-2 and Teneurin-4 expression levels could be of prognostic value in ovarian cancer.