Revolutionizing Implantation Studies: Uterine-Specific Models and Advanced Technologies

Implantation is a complex and tightly regulated process essential for the establishment of pregnancy. It involves dynamic interactions between a receptive uterus and a competent embryo, orchestrated by ovarian hormones such as estrogen and progesterone. These hormones regulate proliferation, differentiation, and gene expression within the three primary uterine tissue types: myometrium, stroma, and epithelium. Advances in genetic manipulation, particularly the Cre/loxP system, have enabled the in vivo investigation of the role of genes in a uterine compartmental and cell type-specific manner, providing valuable insights into uterine biology during pregnancy and disease. The development of endometrial organoids has further revolutionized implantation research. They mimic the native endometrial structure and function, offering a powerful platform for studying hormonal responses, implantation, and maternal-fetal interactions. Combined with omics technologies, these models have uncovered the molecular mechanisms and signaling pathways that regulate implantation. This review provides a comprehensive overview of uterine-specific genetic tools, endometrial organoids, and omics. We explore how these advancements enhance our understanding of implantation biology, uterine receptivity, and decidualization in reproductive research.

Systematic review on the DNA methylation role in endometriosis: current evidence and perspectives

BACKGROUND

Endometriosis appears to have a multilayered etiology, with genetic and epigenetic factors each contributing half of the pathogenesis. The molecular processes that underlie the onset of endometriosis are yet unclear, but it is assumed that an important contributor in the etiopathology of the disease is DNA methylation.

METHODS

We conducted a systematic review of the literature regarding DNA methylation in endometriosis following PRISMA guidelines. Records were obtained from PubMed and Web of Science on May 31, 2024. Original research articles analyzing regional or genome-wide DNA methylation in patients with confirmed endometriosis (by surgery and/or histological examination) were given consideration for inclusion. Only human studies were included, and there were no restrictions on the types of tissue that was analyzed (i.e., endometrium, blood, or fetal tissue). The study selection process was run by two manual reviewers. In parallel, an adapted virtual artificial intelligence-powered reviewer operated study selection and results were compared with the manual reviewers' selection. Studies were divided into targeted (e.g., single gene or region level) and epigenome-wide association studies. For each, we extracted a list of genes studied with precise location of CpGs analyzed and the DNA methylation status according to the groups compared. Quality assessment of studies was performed following the Newcastle-Ottawa scale. Quality of evidence was graded following the Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

A total of 955 studies were screened, and 70 were identified as relevant for systematic review. Our analyses displayed that endometriosis could be polyepigenetic and with alterations in specific genes implicated in major signaling pathways contributing to the disease etiopathology (cell proliferation, differentiation, and division [PI3K-Akt and Wnt-signaling pathway], cell division [MAPK pathway], cell adhesion, cell communication, developmental processes, response to hormone, apoptosis, immunity, neurogenesis, and cancer).

CONCLUSION

Our systematic review indicates that endometriosis is associated with DNA methylation modifications at specific genes involved in key endometrial biological processes, particularly in the ectopic endometrium. As DNA methylation appears to be an integral component of the pathogenesis of endometriosis, the identification of DNA methylation biomarkers would likely help better understand its causes and aggravating factors as well as potentially facilitate its diagnosis and support the development of new therapeutic approaches.

Molecular Basis of Impaired Decidualization in the Eutopic Endometrium of Endometriosis Patients

Endometriosis is a chronic gynecological disorder characterized by the presence of endometrial tissue outside the uterine cavity. A common feature of this pathology is the impaired decidualization of endometrial stromal cells, a critical process that prepares the uterus for embryo implantation. This decidualization defect has been mechanistically linked to progesterone resistance in endometriotic lesions. However, the presence and underlying mechanisms of decidualization defects in the eutopic endometrium of women with endometriosis remain controversial. The aim of the present study is to integrate and discuss molecular evidence from both in vivo and in vitro studies examining decidualization alterations in the eutopic endometrium of patients with endometriosis. Multiple studies have demonstrated impaired decidualization in the eutopic endometrium of women with endometriosis. These alterations have been reported on multiple genes, signaling pathways, and epigenetic processes. However, additional functional studies are warranted to elucidate whether these decidualization defects directly contribute to endometriosis-associated infertility. A better understanding of the decidualization process and its dysregulation in endometriosis will not only advance the development of targeted fertility treatments but also facilitate the design of more effective therapeutic strategies for managing this chronic condition.

Endometrial Receptivity-Lessons from "Omics"

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

A critical review of the recent concept of regulatory performance of DNA Methylations, and DNA methyltransferase enzymes alongside the induction of immune microenvironment elements in recurrent pregnancy loss

Recurrent pregnancy Loss (RPL)is a frequent and upsetting condition. Besides the prevalent cause of RPL including chromosomal defects in the embryo,the effect of translational elements like alterations of epigenetics are of great importance. The emergence of epigenetics has offered a fresh outlook on the causes and treatment of RPL by focusing on the examination of DNA methylation. RPL may arise as a result of aberrant DNA methylation of imprinted genes, placenta-specific genes, immune-related genes, and sperm DNA, which may have a direct or indirect impact on embryo implantation, growth, and development. Moreover, the distinct immunological tolerogenic milieu established at the interface between the mother and fetus plays a crucial role in sustaining pregnancy. Given this, there has been a great deal of interest in the regulation of DNA methylation and alterations in the cellular components of the maternal-fetal immunological milieu. The research on DNA methylation's role in RPL incidence and the control of the mother-fetal immunological milieu is summed up in this review.

Epigenetic Dysregulation in Endometriosis: Implications for Pathophysiology and Therapeutics

Endometriosis is a prevalent gynecological condition associated with pelvic pain and infertility. Despite more than a century of research, the etiology of endometriosis still eludes scientific consensus. This lack of clarity has resulted in suboptimal prevention, diagnosis, and treatment options. Evidence of genetic contributors to endometriosis is interesting but limited; however, significant progress has been made in recent years in identifying an epigenetic role in the pathogenesis of endometriosis through clinical studies, in vitro cell culture experiments, and in vivo animal models. The predominant findings include endometriosis-related differential expression of DNA methyltransferases and demethylases, histone deacetylases, methyltransferases, and demethylases, and regulators of chromatin architecture. There is also an emerging role for miRNAs in controlling epigenetic regulators in the endometrium and endometriosis. Changes in these epigenetic regulators result in differential chromatin organization and DNA methylation, with consequences for gene expression independent of a genetic sequence. Epigenetically altered expression of genes related to steroid hormone production and signaling, immune regulation, and endometrial cell identity and function have all been identified and appear to play into the pathophysiological mechanisms of endometriosis and resulting infertility. This review summarizes and critically discusses early seminal findings, the ever-growing recent evidence of epigenetic contributions to the pathophysiology of endometriosis, and implications for proposed epigenetically targeted therapeutics.

Are epigenetic mechanisms and nutrition effective in male and female infertility?

This review discusses epigenetic mechanisms and the relationship of infertility in men and women in relation to parameters pertaining to nutrition. The prevalence of infertility worldwide is 8-12 %, and one out of every eight couples receives medical treatment. Epigenetic mechanisms, aging, environmental factors, dietary energy and nutrients and non-nutrient compounds; more or less energy intake, and methionine come into play in the occurrence of infertility. It also interacts with vitamins B12, D and B6, biotin, choline, selenium, zinc, folic acid, resveratrol, quercetin and similar factors. To understand the molecular mechanisms regulating the expression of genes that affect infertility, the environment, the role of genotype, age, health, nutrition and changes in the individual's epigenotype must first be considered. This will pave the way for the identification of the unknown causes of infertility. Insufficient or excessive intake of energy and certain macro and micronutrients may contribute to the occurrence of infertility as well. In addition, it is reported that 5-10 % of body weight loss, moderate physical activity and nutritional interventions for improvement in insulin sensitivity contribute to the development of fertility. Processes that pertain to epigenetics carry alterations which are inherited yet not encoded via the DNA sequence. Nutrition is believed to have an impact over the epigenetic mechanisms which are effective in the pathogenesis of several diseases like infertility. Epigenetic mechanisms of individuals with infertility are different from healthy individuals. Infertility is associated with epigenetic mechanisms, nutrients, bioactive components and numerous other factors.

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.

HOXA10 DNA Methylation Level in the Endometrium Women with Endometriosis: A Systematic Review

Endometriosis is an inflammatory chronic systemic disease resulting in pelvic pain and infertility. However, despite a high prevalence of endometriosis, disease identification is still insufficient, and a high percentage of misdiagnosing was observed. Hence, a comprehensive study needs to be done to improve our understanding of the pathogenesis of endometriosis. Aberrant hypermethylation of HOXA10 has been reported to play a role in endometriosis. Thus, a comprehensive literature search was conducted to identify the DNA methylation level of HOXA10 among endometriosis patients across populations. The literature search was done using PubMed, Scopus, EBSCOhost, and Science Direct applying (HOXA10 OR "homeobox A10" OR "HOXA-10" OR HOX1) AND ("DNA methylation" OR methylation) AND (endometriosis OR endometrioma) as keywords. From 491 retrieved studies, five original articles investigating the DNA methylation level of HOXA10 from endometrium tissues among endometriosis women were included. All five included studies were classified as high-quality studies. High HOXA10 DNA methylation level was observed in the endometrium tissue of women with endometriosis in all the included studies. The secretory phase was identified as the best sampling time for HOXA10 DNA methylation study in endometriosis, and the most studied DNA methylation site is the promoter region of the HOXA10. However, more studies are needed to expose the HOXA10 mechanism in the pathogenesis of endometriosis.

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

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

Aberrant Hoxa10 gene methylation as a mechanism for endosulfan-induced implantation failures in rats

DNA methylation is a well-established epigenetic mechanism controlling gene expression. Environmental chemicals, such as pesticides have been shown to alter DNA methylation. We have previously shown that the insecticide endosulfan impairs female fertility in rats by increasing the rate of preimplantation embryo losses. In this study, we evaluated whether early postnatal exposure to endosulfan affects long-term transcriptional regulation of Homeobox A10 (Hoxa10) gene, which is a key marker of endometrial receptivity. Female rats were neonatally exposed to 6 or 600 μg/kg/day (ENDO6 and ENDO600, respectively) of endosulfan and uterine samples collected on gestational day (GD) 5. Hoxa10 protein and mRNA levels were assessed by immunohistochemistry and quantitative real-time PCR (qRT-PCR), respectively. In silico analysis of enzyme-specific restriction sites and predicted transcription factors were performed to investigate the methylation status of the regulatory regions of Hoxa10 gene by methylation-sensitive restriction enzymes-PCR technique. The expression of the DNA methyltransferases (Dnmts) was also evaluated. ENDO600 showed a decreased uterine Hoxa10 expression at protein and transcript level, while ENDO6 decreased only the level of transcripts, during the receptive stage. In addition, endosulfan increased levels of Dnmt3a and Dnmt3b. Dysregulation of DNA methylation patterns of Hoxa10 regulatory regions was detected in ENDO6- and ENDO600-treated rats. All these results suggest that aberrant DNA methylation in Hoxa10 gene could be an underlining mechanism contributing to explain endosulfan-induced preimplantation losses.

Epigenetic Factors in Eutopic Endometrium in Women with Endometriosis and Infertility

Eutopic endometrium in patients with endometriosis is characterized by aberrant expression of essential genes during the implantation window. It predisposes to disturbance of endometrial receptivity. The pathomechanism of implantation failures in women with endometriosis remains unclear. This paper aims to summarize the knowledge on epigenetic mechanisms in eutopic endometrium in the group of patients with both endometriosis and infertility. The impaired DNA methylation patterns of gene promoter regions in eutopic tissue was established. The global profile of histone acetylation and methylation and the analysis of selected histone modifications showed significant differences in the endometrium of women with endometriosis. Aberrant expression of the proposed candidate genes may promote an unfavorable embryonic implantation environment of the endometrium due to an immunological dysfunction, inflammatory reaction, and apoptotic response in women with endometriosis. The role of the newly discovered proteins regulating gene expression, i.e., TET proteins, in endometrial pathology is not yet completely known. The cells of the eutopic endometrium in women with endometriosis contain a stable, impaired methylation pattern and a histone code. Medication targeting critical genes responsible for the aberrant gene expression pattern in eutopic endometrium may help treat infertility in women with endometriosis.

HOX cluster and their cofactors showed an altered expression pattern in eutopic and ectopic endometriosis tissues

Endometriosis is major gynecological disease that affects over 10% of women worldwide and 30%-50% of these women have pelvic pain, abnormal uterine bleeding and infertility. The cause of endometriosis is unknown and there is no definite cure mainly because of our limited knowledge about its pathophysiology at the cellular and molecular levels. Therefore, demystifying the molecular mechanisms that underlie endometriosis is essential to develop advanced therapies for this disease. In this regard, HOX genes are remarkable because of their critical role in endometrial development and receptivity during implantation, which is attributed to their ability to mediate some of the sex steroid functions during the reproductive period. Access to the expression profiles of these genes would provide the necessary information to uncover new genes for endometriosis and assist with disease diagnosis and treatment. In this study we demonstrate an altered expression pattern for the HOX clusters (A-D) and their cofactors in both eutopic and ectopic conditions compared to control tissue biopsies. Remarkably, most of the intensive changes occurred in eutopic samples from endometriosis patients compared to control tissue biopsies. Pathway analysis revealed the involvement of differentially expressed genes in cancer that correlate with an association between endometriosis and cancer. Our results suggest critical roles for the HOX cluster and their cofactors in endometriosis pathophysiology.

Disturbed progesterone signalling in an advanced preclinical model of endometriosis

RESEARCH QUESTION

Do human endometriosis organoids recapitulate aberrant progesterone signalling in the disease to serve as advanced experimental models for uncovering epigenetic mechanisms involved in attenuated progesterone response in endometriosis?

DESIGN

Initially, the organoids were established from acquired biopsies (women with and without endometriosis) and characterized by morphological, histological and immunostaining analyses.

RESULTS

A panel of endometriosis-related genes showed a pattern of expressions in cytochrome c oxidase subunit II (COX2), matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase-3 (TIMP3), transforming growth factor beta 1 (TGF-β1), and zinc finger E-box binding homeobox 1 (ZEB1), and a contradictory expression pattern for cadherin (CDH1), POU class 5 homeobox 1 (POU5F1; also known as OCT4), and Nanog homeobox (NANOG) in the endometriosis organoids that is concordant with published research. These endometriosis organoids failed to upregulate 17β-Hydroxysteroid dehydrogenase 2 (17HSDβ2), progestogen associated endometrial protein (PAEP), secreted phosphoprotein 1 (SPP1), and leukaemia inhibitory factor (LIF) in response to progesterone at the level observed in control endometrium organoids. Progesterone receptor B (PRB) gene expression significantly decreased in both eutopic and ectopic organoids compared with control endometrium organoids. DNA hypermethylation, as an epigenetic mechanism for suppression of transcription, was detected at the PRB promoter in the eutopic, but not ectopic, organoids. Therefore, other epigenetic mechanisms, such as histone modifications and microRNAs, may be responsible for PRB downregulation in ectopic organoids.

CONCLUSIONS

Endometriosis organoids are powerful preclinical models that can be used to investigate the molecular mechanisms involved in endometriosis-associated progesterone resistance.

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.

Ovulation Induction Changes Epigenetic Marks of Imprinting Genes in Mice Fetus Organs

Objective

Genomic imprinting is an epigenetic phenomenon that plays a critical role in normal development of embryo. Using exogenous hormones during assisted reproductive technology (ART) can change an organism hormonal profile and subsequently affect epigenetic events. Ovarian stimulation changes gene expression and epigenetic pattern of imprinted genes in the organs of mouse fetus.

Materials and Methods

For this experimental study, expression of three imprinted genes H19, Igf2 (Insulin-like growth factor 2) and Cdkn1c (Cyclin-dependent kinase inhibitor 1C), which have important roles in development of placenta and embryo, and the epigenetic profile of their regulatory region in some tissues of 19-days-old female fetuses, from female mice subjected to ovarian stimulation, were evaluated by quantitative reverse-transcription PCR (qRT-PCR) and Chromatin immunoprecipitation (ChIP) methods.

Results

H19 gene was significantly lower in heart (P<0.05), liver (P<0.05), lung (P<0.01), placenta (P<0.01) and ovary (P<0.01). It was significantly higher in kidney of ovarian stimulation group compared to control fetuses (P<0.05). Igf2 expression was significantly higher in brain (P<0.05) and kidney (P<0.05), while it was significantly lower in lung of experimental group fetuses in comparison with control fetuses (P<0.05). Cdkn1c expression was significantly higher in lung (P<0.05). It was significantly decreased in placenta of experimental group fetuses rather than the control fetuses (P<0.05). Histone modification data and DNA methylation data were in accordance to the gene expression profiles.

Conclusion

Results showed altered gene expressions in line with changes in epigenetic pattern of their promoters in the ovarian stimulation group, compared to normal cycle.

Mixed-lineage leukaemia 1 contributes to endometrial stromal cells progesterone responsiveness during decidualization

Studies have reported that non‐receptive endometrium or abnormal decidualization was closely related to recurrent implantation failure (RIF). MLL1 is a histone H3 lysine 4 trimethylation (H3K4me3) transferase that regulates the transcriptional activation of target genes. The role of MLL1 has been underexplored during decidualization. In our research, we found the expression of MLL1 was closely related to endometrial receptivity, and it was responsible to hormone stimulation. Inhibiting the function of MLL1 by MM102 reduced the transformation of HESCs. Furthermore, down‐regulation of MLL1 by siRNA transfection significantly decreased PGR and its target genes expression. MLL1 act as a co‐activator of ERα, and both of them were recruited to PGR regulatory regions, thus promote PGR transcription. Our study showed that MLL1 plays a key role in promoting progesterone signalling transmission.

Genome-wide DNA methylation profiling in ectopic and eutopic of endometrial tissues

PURPOSE

Endometriosis is a gynecological disease that causes the uterine lining to appear in other organs outside the uterus. As DNA methylation has an important role in this disorder, its profiling can reveal new information to improve the diagnosis and treatment of endometriosis patients.

METHODS

We conducted a genome-wide methylation profiling of ectopic and eutopic endometrial tissues from women with and without endometriosis using Infinium Human Methylation 450K BeadChip arrays. DNA methylation samples were collected from nine ectopic and nine eutopic endometrial tissues of endometriosis and six endometrial tissues of healthy controls.

RESULTS

Correlation heatmaps and the principal component analysis divided the samples into two clusters, one consisting of all ectopic samples and the other consisting of both eutopic and control samples unexpectedly without segregation between them. The assay identified a group of methylated genes that were overrepresented in biological processes, including abnormality in signaling, development, and adhesion of cells. Pathway analysis revealed disruption in HTLV infection pathways, PI3K-Akt, oxytocin, and relaxin signaling. Moreover, we found eutopic lesions are strongly associated with autoimmune disease.

CONCLUSIONS

Our results confirmed the role of DNA methylation alternations in endometriosis development and pathogenesis. Our finding suggests aberrant DNA methylation can activate several signaling pathways including PI3k-AKT signaling, relaxin, and oxytocin which are associated with the pathogenesis of endometriosis.

A Case of Identity: HOX Genes in Normal and Cancer Stem Cells

Stem cells are undifferentiated cells that have the unique ability to self-renew and differentiate into many different cell types. Their function is controlled by core gene networks whose misregulation can result in aberrant stem cell function and defects of regeneration or neoplasia. HOX genes are master regulators of cell identity and cell fate during embryonic development. They play a crucial role in embryonic stem cell differentiation into specific lineages and their expression is maintained in adult stem cells along differentiation hierarchies. Aberrant HOX gene expression is found in several cancers where they can function as either oncogenes by sustaining cell proliferation or tumor-suppressor genes by controlling cell differentiation. Emerging evidence shows that abnormal expression of HOX genes is involved in the transformation of adult stem cells into cancer stem cells. Cancer stem cells have been identified in most malignancies and proved to be responsible for cancer initiation, recurrence, and metastasis. In this review, we consider the role of HOX genes in normal and cancer stem cells and discuss how the modulation of HOX gene function could lead to the development of novel therapeutic strategies that target cancer stem cells to halt tumor initiation, progression, and resistance to treatment.

Epigenetic role of the nuclear factor NF-Y on ID gene family in endometrial tissues of women with endometriosis: a case control study

BACKGROUND

A predominant difference between endometrial and normal cells is higher proliferation rate in the former cells which is benign. The genes of inhibitor of differentiation (ID) family play a major role in cell proliferation regulation which might be targeted by the nuclear transcription factor Y (NF-Y) for subsequent epigenetic modifications through the CCAAT box regulatory region. The present study was designed to investigate the epigenetic role of NF-Y on ID gene family in endometrial tissue of patients with endometriosis.

MATERIALS & METHODS

In this case-control study, 20 patients with endometriosis and 20 normal women were examined for the relative expression of the NF-YA, NF-YB, NF-YC and ID genes by real-time PCR during the proliferative phase. The occupancy of NF-Y on CCAAT box region of ID genes was investigated using chromatin immunoprecipitation (ChIP) followed by real-time PCR.

RESULTS

The NF-YA was over-expressed in eutopic endometrium during the proliferative phase. Although the expression level of NF-YB and NF-YC were unchanged in eutopic samples, they were remarkably higher in ectopic group (P<0.05). The ID2 and ID3 genes were up-regulated in ectopic and eutopic tissues, however ID1 and ID4 genes were down-regulated in these samples (P<0.05). The ChIP analysis revealed significant enrichment of NF-Y on regulatory regions of ID2,3 genes in eutopic group, but reduced binding level of NF-Y to the ID1,3 promoters in ectopic specimens (P<0.05).

CONCLUSION

The ability of NF-Y to regulate ID genes via CCAAT box region suggests the possible role of NF-Y transcription factor in epigenetic changes in endometrial tissues which may open novel avenues in finding new therapeutic strategies.