Cell adhesion molecules and endometriosis

CADM2 participates in endometriosis development by influencing the epithelial-mesenchymal transition

Endometriosis (EM) is a common gynecologic condition that often leads to infertility in women of reproductive age. Cell adhesion molecule 2 (CADM2) is involved in maintaining cell adhesion and polarity, as well as suppressing tumors. However, the role and mechanism of CADM2 in endometriosis is unclear. Therefore, this study evaluated the expression levels of CADM2 and epithelial-mesenchymal transition (EMT)-related marker proteins (E-cadherin, α-SMA, and N-cadherin). Compared to normal endometrial tissue, CADM2 was expressed at low levels in ectopic endometrial tissue from patients with EM. We performed clone formation assays, wound healing assays, and Transwell cell invasion assays to investigate the effects of CADM2 on the biological behavior of endometriosis epithelial cells (11Z) and ectopic endometrial stromal cells (EESCs). The growth, migration, and invasion abilities of these cells were significantly inhibited by overexpression of CADM2. The results were reversed after the knockdown of CADM2. Finally, western blotting (WB) was utilized to detect the effect of CADM2 on EMT in endometriosis cells. CADM2 inhibited EMT in endometriosis cells. In conclusion, our study suggests that CADM2 is a negative regulator of endometriosis development and may inhibit endometriosis development by suppressing EMT.

Impaired bone morphogenetic protein (BMP) signaling pathways disrupt decidualization in endometriosis

Endometriosis is linked to increased infertility and pregnancy complications due to defective endometrial decidualization. We hypothesized that identification of altered signaling pathways during decidualization could identify the underlying cause of infertility and pregnancy complications. Our study reveals that transforming growth factor β (TGFβ) pathways are impaired in the endometrium of individuals with endometriosis, leading to defective decidualization. Through detailed transcriptomic analyses, we discovered abnormalities in TGFβ signaling pathways and key regulators, such as SMAD4, in the endometrium of affected individuals. We also observed compromised activity of bone morphogenetic proteins (BMP), a subset of the TGFβ family, that control endometrial receptivity. Using 3-dimensional models of endometrial stromal and epithelial assembloids, we showed that exogenous BMP2 improved decidual marker expression in individuals with endometriosis. Our findings reveal dysfunction of BMP/SMAD signaling in the endometrium of individuals with endometriosis, explaining decidualization defects and subsequent pregnancy complications in these individuals.

Impaired bone morphogenetic protein signaling pathways disrupt decidualization in endometriosis

It is hypothesized that impaired endometrial decidualization contributes to decreased fertility in individuals with endometriosis. To identify the molecular defects that underpin defective decidualization in endometriosis, we subjected endometrial stromal cells from individuals with or without endometriosis to time course in vitro decidualization with estradiol, progesterone, and 8-bromo-cyclic-AMP (EPC) for 2, 4, 6, or 8 days. Transcriptomic profiling identified differences in key pathways between the two groups, including defective bone morphogenetic protein (BMP)/SMAD4 signaling (ID2, ID3, FST), oxidate stress response (NFE2L2, ALOX15, SLC40A1), and retinoic acid signaling pathways (RARRES, RARB, ALDH1B1). Genome-wide binding analyses identified an altered genomic distribution of SMAD4 and H3K27Ac in the decidualized stromal cells from individuals without endometriosis relative to those with endometriosis, with target genes enriched in pathways related to signaling by transforming growth factor β (TGFβ), neurotrophic tyrosine kinase receptors (NTRK), and nerve growth factor (NGF)-stimulated transcription. We found that direct SMAD1/5/4 target genes control FOXO, PI3K/AKT, and progesterone-mediated signaling in decidualizing cells and that BMP2 supplementation in endometriosis patient-derived assembloids elevated the expression of decidualization markers. In summary, transcriptomic and genome-wide binding analyses of patient-derived endometrial cells and assembloids identified that a functional BMP/SMAD1/5/4 signaling program is crucial for engaging decidualization.

Biomarker identification for endometriosis as a target for real-time intraoperative fluorescent imaging: A new approach using transcriptomic analysis to broaden the search for potential biomarkers

Intra-operative fluorescent imaging of endometriosis could help to optimize surgical treatment. Potential biomarkers to use as target for endometriosis-binding fluorescent probes were identified using a new five-phase transcriptomics-based approach to broaden the search for biomarkers. Using publicly available datasets, a differentially expressed gene (DEG) analysis was performed for endometriosis versus surgically relevant surrounding tissue (peritoneum, bladder, sigmoid, rectum, transverse colon, small intestine, vagina, and fallopian tubes) for which data was available. The remaining relevant surrounding tissues were analyzed for low expression levels. DEGs with a predicted membranous or extracellular location and with low expression levels in surrounding tissue were identified as candidate targets. Modified Target Selection Criteria were used to rank candidate targets based on the highest potential for use in fluorescent imaging. 29 potential biomarkers were ranked, resulting in Folate receptor 1 as the most potential biomarker. This is a first step towards finding a fluorescent tracer for intra-operative visualization of endometriosis. Additionally, this approach, using transcriptomics analysis to identifying candidate targets for a specific type of tissue for use in fluorescence-guided surgery could be translated to other surgical fields. TWEETABLE ABSTRACT: A new approach using transcriptomics analysis is shown to identify candidate targets for intra-operative fluorescent imaging for endometriosis, resulting in 29 potential candidates.

Molecular Mechanisms of Endometriosis Revealed Using Omics Data

Endometriosis is a gynecological disorder prevalent in women of reproductive age. The primary symptoms include dysmenorrhea, irregular menstruation, and infertility. However, the pathogenesis of endometriosis remains unclear. With the advent of high-throughput technologies, various omics experiments have been conducted to identify genes related to the pathophysiology of endometriosis. This review highlights the molecular mechanisms underlying endometriosis using omics. When genes identified in omics experiments were compared with endometriosis disease genes identified in independent studies, the number of overlapping genes was moderate. However, the characteristics of these genes were found to be equivalent when functional gene set enrichment analysis was performed using gene ontology and biological pathway information. These findings indicate that omics technology provides invaluable information regarding the pathophysiology of endometriosis. Moreover, the functional characteristics revealed using enrichment analysis provide important clues for discovering endometriosis disease genes in future research.

Effects of pharmacological inhibition of hyaluronic acid synthesis on experimental endometriosis

BACKGROUND

Dysregulated hyaluronic acid (HA) metabolism has been shown to be implicated in several pathologies including endometriosis. 4-Methylumbelliferone (4MU) is an HA synthesis inhibitor with proven antitumour activity. In this study, we aim to evaluate the effect of 4MU on endometriosis development both in vivo and in vitro.

METHODS

Endometriosis was surgically induced by uterine tissue auto-transplantation in 32 two-month-old BALB/c mice. Animals were designated into the early or late starting treatment group, which initiated on day 2 or day 15 after surgery, respectively. Within each group, 4MU 200 mg/kg/day or vehicle (Control) were administered by oesophageal gavage for 28 days. After sacrifice, the percentage of developed lesions, lesion size, cell proliferation, vascularization and HA deposition within the endometriotic-like lesions were evaluated. Cell viability was assessed in endometrial epithelial cells (ECC-1) and in endometrial stromal cells (t-HESC); and migration was evaluated in t-HESC.

RESULTS

There was a significant reduction in the percentage of developed lesions in mice that started the 4MU treatment on day 2 compared with its respective control group, and compared with those that started treatment on day 15. However, no significant changes were found when analysing endometriotic-like lesion's cell proliferation, vascularization and HA deposition. In vitro, both cell viability and migration were inhibited by 4MU treatment.

CONCLUSIONS

The inhibition of HA synthesis could be a beneficial and alternative option to treat endometriosis at the early stage of the disease. Further research is necessary to elucidate 4MU's mechanism of action and better strategies for delivering this promising drug.

Altered Differential Expression of Genes and microRNAs Related to Adhesion and Apoptosis Pathways in Patients with Different Phenotypes of Endometriosis

We aim to investigate the expression of genes (MAPK1 and CAPN2) and microRNAs (miR-30a-5p, miR-7-5p, miR-143-3p, and miR-93-5p) involved in adhesion and apoptosis pathways in superficial peritoneal endometriosis (SE), deep infiltrating endometriosis (DE), and ovarian endometrioma (OE), and to evaluate whether these lesions share the same pathophysiological mechanisms. We used samples of SE (n = 10), DE (n = 10), and OE (n = 10), and endometrial biopsies of these respective patients affected with endometriosis under treatment at a tertiary University Hospital. Endometrial biopsies collected in the tubal ligation procedure from women without endometriosis comprised the control group (n = 10). Quantitative real-time polymerase chain reaction was performed. The expression of MAPK1 (p < 0.0001), miR-93-5p (p = 0.0168), and miR-7-5p (p = 0.0006) was significantly lower in the SE group than in the DE and OE groups. The expression of miR-30a (p = 0.0018) and miR-93 (p = 0.0052) was significantly upregulated in the eutopic endometrium of women with endometriosis compared to the controls. MiR-143 (p = 0.0225) expression also showed a statistical difference between the eutopic endometrium of women with endometriosis and the control group. In summary, SE showed lower pro-survival gene expression and miRNAs involved in this pathway, indicating that this phenotype has a different pathophysiological mechanism compared to DE and OE.

Non-invasive diagnosis of endometriosis: Immunologic and genetic markers

Endometriosis, a benign gynecologic and chronic inflammatory disease, is defined by the presence of endometrial tissue outside the uterus characterized mainly by pelvic pain and infertility. Because endometriosis affects approximately 10% of females, it represents a significant socioeconomic burden worldwide having tremendous impact on daily quality of life. Accurate and prompt diagnosis is crucial for the management of this debilitating disorder. Unfortunately, diagnosis is typically delayed to lack of specific symptoms and readily accessible biomarkers. Although histopathologic examination remains the current gold standard, this approach is highly invasive and not applicable for early screening. Recent work has focused on the identification of reliable biomarkers including immunologic, ie, immune cells, antibodies and cytokines, as well as genetic and biochemical markers, ie, microRNAs, lncRNAs, circulating and mitochondrial nucleic acids, along with some hormones, glycoproteins and signaling molecules. Confirmatory research studies are, however, needed to more fully establish these markers in the diagnosis, progression and staging of these endometrial lesions.

An Update on the Multifaceted Role of NF-kappaB in Endometriosis

Endometriosis remains a common but challenging gynecological disease among reproductive-aged women with an unclear pathogenesis and limited therapeutic options. Numerous pieces of evidence suggest that NF-κB signaling, a major regulator of inflammatory responses, is overactive in endometriotic lesions and contributes to the onset, progression, and recurrence of endometriosis. Several factors, such as estrogen, progesterone, oxidative stress, and noncoding RNAs, can regulate NF-κB signaling in endometriosis. In the present review, we discuss the mechanisms by which these factors regulate NF-κB during endometriosis progression and provide an update on the role of NF-κB in affecting endometriotic cells, peritoneal macrophages (PMs) as well as endometriosis-related symptoms, such as pain and infertility. Furthermore, the preclinical drugs for blocking NF-κB signaling in endometriosis are summarized, including plant-derived medicines, NF-κB inhibitors, other known drugs, and the potential anti-NF-κB drugs predicted through the Drug-Gene Interaction Database. The present review discusses most of the studies concerning the multifaceted role of NF-κB signaling in endometriosis and provides a summary of NF-κB-targeted treatment in detail.

Bioinformatical analysis of the key differentially expressed genes and associations with immune cell infiltration in development of endometriosis

Background

This study explored the key genes related to immune cell infiltration in endometriosis.

Results

The Gene Expression Omnibus (GEO) datasets (GSE7305, GSE7307, and GSE11691), containing a total of 37 endometriosis and 42 normal tissues, were retrieved and analyzed to determine the differentially expressed genes (DEGs). Gene ontology (GO) annotations and Kyoto Encyclopedia of Genes (KEGG) analysis were performed to identify the pathways that were significantly enriched. The xCell software was used to analyze immune cell infiltration and correlation analyses were performed to uncover the relationship between key genes and immune cells. The analysis identified 1031 DEGs (581 upregulated and 450 downregulated DEGs), while GO analysis revealed altered extracellular matrix organization, collagen-containing extracellular matrix, and glycosaminoglycan binding and KEGG enrichment showed genes related to metabolic pathways, pathways in cancer, phosphatidylinositol 3-kinase-protein kinase B (PI3K-Akt) signaling, proteoglycans in cancer, and the mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, the protein–protein interaction network revealed 10 hub genes, i.e., IL6, FN1, CDH1, CXCL8, IGF1, CDK1, PTPRC, CCNB1, MKI67, and ESR1. The xCell analysis identified immune cells with significant changes in all three datasets, including CD4⁺ and CD8⁺ T cells, CD8⁺ Tem, eosinophils, monocytes, Th1 cells, memory B-cells, activated dendritic cells (aDCs), and plasmacytoid dendritic cells (pDCs). These 10 hub genes were significantly associated with at least three types of immune cells.

Conclusions

Aberrant gene expression was related to abnormal infiltration of different immune cells in endometriosis and was associated with endometriosis development by affecting the tissue microenvironment and growth of ectopic endometrial cells.

Reduced frequency of perforin-positive CD8+ T cells in menstrual effluent of endometriosis patients

Endometriosis is a widespread disease and commonly reduces the life quality of those affected. Scientific literature indicates different underlying immunological changes. Frequently examined tissues are peripheral blood, endometrial tissue and peritoneal fluid. Yet, knowledge on immunological differences in menstrual effluent (ME) is scarce. In this study, between January 2018 and August 2019, 12 women with endometriosis (rASRM classification: stages I-IV) and 11 healthy controls were included. ME was collected using menstrual cups and venous blood samples (PB) were taken. Mononuclear cells were obtained from ME (MMC) and PB (PBMC) and analyzed using flow cytometry. Concentrations of cell adhesion molecules (ICAM-I and VCAM-I) and cytokines (IL-6, IL-8 and TNF-α) were measured using ELISA. CD8 + T cells obtained from ME were significantly less often perforin-positive in women with endometriosis compared to healthy controls. A comparison between MMC and PBMC revealed that MMC contained significantly less T cells and more B cells. The CD4/CD8 ratio was significantly higher in MMC, and Tregs were significantly less frequently in MMC. In ME, T cells and NK cells expressed significantly more CD69. NK cells obtained from ME were predominantly CD56^bright/CD16^dim and had a lower frequency of perforin + cells compared to PBMC NK cells. Moreover, ICAM-1 plasma levels were significantly reduced in women with endometriosis compared to healthy controls. In conclusion, CD8 + T cells obtained from the ME were significantly less perforin-positive in endometriosis patients indicating a reduced cytotoxic potential. MMC are distinctively different from PBMC and, thus, seem to be of endometrial origin.

Peritoneal Fluid from Patients with Ovarian Endometriosis Displays Immunosuppressive Potential and Stimulates Th2 Response

Endometriosis is a common gynaecological disorder characterized by the ectopic growth of endometrial tissue outside the uterine cavity. It is associated with chronic pelvic inflammation and autoimmune reactivity manifesting by autoantibody production and abrogated cellular immune responses. Endometriotic peritoneal fluid contains various infiltrating leucocyte populations and a bulk of proinflammatory and immunoregulatory cytokines. However, the nature and significance of the peritoneal milieu in women with endometriosis still remains obscure. Therefore, the aim of the present study was to investigate the immunoregulatory activity of the peritoneal fluid (PF) from women with endometriosis. The peritoneal fluid samples were collected during laparoscopic surgery from 30 women with and without endometriosis. Immunoregulatory cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ and TNF) and chemokines (CCL2, CCL5, CXCL8 and CXCL9) were evaluated in PF and culture supernatants generated by unstimulated and CD3/CD28/IL-2-stimulated CD4⁺ T cells cultured in the presence of PF. The effect of PF on the generation of Treg and Th17 cells in CD4⁺ T cell cultures, as well as the natural cytotoxic activity of peripheral blood mononuclear cells, was also investigated. Concentrations of IL-6, IL-10, CCL2, CXCL8 and CXCL9 were significantly upregulated in the PF from women with endometriosis when compared to control women, whereas concentrations of other cytokines and chemokines were unaffected. The culturing of unstimulated and CD3/CD28/IL-2-stimulated CD4⁺ T cells in the presence of endometriotic PF resulted in the downregulation of their IL-2, IFN-γ, IL-17A and TNF production as compared to culture medium alone. On the other side, endometriotic PF significantly stimulated the production of IL-4 and IL-10. Endometriotic PF also stimulated the release of CCL2 and CXCL8, whereas the production of CCL5 and CXCL9 was downregulated. Endometriotic PF stimulated the generation of Treg cells and had an inhibitory effect on the generation of Th17 cells in cultures of CD4⁺ T cells. It also inhibited the NK cell cytotoxic activity of the peripheral blood lymphocytes. These results strongly imply that the PF from patients with endometriosis has immunoregulatory/immunosuppressive activity and shifts the Th1/Th2 cytokine balance toward the Th2 response, which may account for deviation of local and systemic immune responses. However, a similar trend, albeit not a statistically significant one, was also observed in case of PF from women without endometriosis, thus suggesting that peritoneal milieu may in general display some immunoregulatory/immunosuppressive properties. It should be stressed, however, that our present observations were made on a relatively small number of PF samples and further studies are needed to reveal possible mechanism(s) responsible for this phenomenon.

Polyphenols as a Diet Therapy Concept for Endometriosis-Current Opinion and Future Perspectives

Endometriosis represents an often painful, estrogen-dependent gynecological disorder, defined by the existence of endometrial glands and stroma exterior to the uterine cavity. The disease provides a wide range of symptoms and affects women’s quality of life and reproductive functions. Despite research efforts and extensive investigations, this disease’s pathogenesis and molecular basis remain unclear. Conventional endometriosis treatment implies surgical resection, hormonal therapies, and treatment with nonsteroidal anti-inflammatory drugs, but their efficacy is currently limited due to many side effects. Therefore, exploring complementary and alternative therapy strategies, minimizing the current treatments’ adverse effects, is needed. Plants are sources of bioactive compounds that demonstrate broad-spectrum health-promoting effects and interact with molecular targets associated with endometriosis, such as cell proliferation, apoptosis, invasiveness, inflammation, oxidative stress, and angiogenesis. Anti-endometriotic properties are exhibited mainly by polyphenols, which can exert a potent phytoestrogen effect, modulating estrogen activity. The available evidence derived from preclinical research and several clinical studies indicates that natural biologically active compounds represent promising candidates for developing novel strategies in endometriosis management. The purpose of this review is to provide a comprehensive overview of polyphenols and their properties valuable for natural treatment strategy by interacting with different cellular and molecular targets involved in endometriosis progression.

The Link Between Stress and Endometriosis: from Animal Models to the Clinical Scenario

There is strong evidence from humans and animal models showing that abnormal functioning of the hypothalamic-pituitary-adrenal (HPA) axis and/or the inflammatory response system disrupts feedback regulation of both neuroendocrine and immune systems, contributing to disease. Stress is known to affect the physiology of pelvic organs and to disturb the HPA axis leading to chronic, painful, inflammatory disorders. A link between stress and disease has already been documented for many chronic conditions. Endometriosis is a complex chronic gynecological disease associated with severe pelvic pain and infertility that affects 10% of reproductive-aged women. Patients report the negative impact of endometriosis symptoms on quality of life, work/study productivity, and personal relationships, which in turn cause high levels of psychological and emotional distress. The relationship between stress and endometriosis is not clear. Still, we have recently demonstrated that stress increases the size and severity of the lesions as well as inflammatory parameters in an animal model. Furthermore, the "controllability" of stress influences the pathophysiology in this model, offering the possibility of using stress management techniques in patients. The crosstalk between stress-inflammation-pain through HPA axis activity indicates that stress relief should alleviate inflammation and, in turn, decrease painful responses. This opens up the opportunity of altering brain-body-brain pathways as potential new therapeutic option for endometriosis. The goal of this review is to gather the research evidence regarding the interaction between stress (psychological and physiological) and the development and progression of endometriosis on the exacerbation of its symptoms with the purpose of proposing new lines of emerging research and possible treatment modalities for this still incurable disease.

Ureaplasma Urealyticum Infection Contributes to the Development of Pelvic Endometriosis Through Toll-Like Receptor 2

Endometriosis is a chronic gynecological disorder, characterized by the presence of ectopic endometrial tissue outside the uterine cavity. Among several hypotheses, Sampson's theory of retrograde menstruation is still applicable. Recent studies have reported the importance of inflammation among endometrial tissue, the peritoneum, and immune cells. However, less is known regarding the role of bacterial infection in the pathophysiology of endometriosis. We hypothesized that Ureaplasma urealyticum infection might contribute to the development of endometriosis by inducing the production of inflammatory mediators by peritoneal mesothelial cells (PMCs), possibly through TLR2. Hence, our objective was to reveal whether PMC infection by U. urealyticum is associated with endometriosis. Moreover, we aimed to demonstrate the molecular mechanism involved in this relationship. We developed a new infection-induced mouse model of endometriosis with wild type and Tlr2-deficient mice. Based on the in vivo mouse model, U. urealyticum-infected mice showed significantly increased numbers and sizes of ectopic endometriotic lesions. U. urealyticum upregulated not only the production of IL-6, CXCL1, and CCL2, but also the expression of ICAM-1, VCAM-1, and MMP2 in murine PMCs. Similarly, endometrial stromal cells dose-dependently produced IL-6, CXCL1, and CCL2 in response to U. urealyticum infection. The series of inflammatory responses in PMCs was mediated mainly through TLR2. The phosphorylation of ERK and JNK was observed when U. urealyticum was added to PMCs and knock out of Tlr2 inhibited these MAPKs phosphorylation. Based on our co-culture study, U. urealyticum-infected PMCs exhibited significantly increased attachment to ESCs compared with uninfected PMCs. Collectively, U. urealyticum infection promotes the development of endometriosis by increasing inflammatory mediators, adhesion molecules, and MMP-2 expression in PMCs through TLR2 signaling. Through our results, we present a theory that infection-induced pelvic inflammation contributes to the initiation and progression of endometriosis. Appropriate treatment of reproductive tract infection may decrease the prevalence of endometriosis.

NK Cells as Potential Targets for Immunotherapy in Endometriosis

Endometriosis is a common gynecological disease defined by the presence of endometrial-like tissue outside the uterus, most frequently on the pelvic viscera and ovaries, which is associated with pelvic pains and infertility. It is an inflammatory disorder with some features of autoimmunity. It is accepted that ectopic endometriotic tissue originates from endometrial cells exfoliated during menstruation and disseminating into the peritoneum by retrograde menstrual blood flow. It is assumed that the survival of endometriotic cells in the peritoneal cavity may be partially due to their abrogated elimination by natural killer (NK) cells. The decrease of NK cell cytotoxic activity in endometriosis is associated with an increased expression of some inhibitory NK cell receptors. It may be also related to the expression of human leukocyte antigen G (HLA-G), a ligand for inhibitory leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1) receptors. The downregulated cytotoxic activity of NK cells may be due to inhibitory cytokines present in the peritoneal milieu of patients with endometriosis. The role of NK cell receptors and their ligands in endometriosis is also confirmed by genetic association studies. Thus, endometriosis may be a subject of immunotherapy by blocking NK cell negative control checkpoints including inhibitory NK cell receptors. Immunotherapies with genetically modified NK cells also cannot be excluded.

Transforming growth factor β1 enhances adhesion of endometrial cells to mesothelium by regulating integrin expression

Endometriosis is the abnormal growth of endometrial cells outside the uterus, causing pelvic pain and infertility. Furthermore, adhesion of endometrial tissue fragments to pelvic mesothelium is required for the initial step of endometriosis formation outside uterus. TGF-β1 and adhesion molecules importantly function for adhesion of endometrial tissue fragments to mesothelium outside uterus. However, the function of TGF-β1 on the regulation of adhesion molecule expression for adhesion of endometrial tissue fragments to mesothelium has not been fully elucidated. Interestingly, transforming growth factor β1 (TGF-β1) expression was higher in endome-triotic epithelial cells than in normal endometrial cells. The adhesion efficiency of endometriotic epithelial cells to meso-thelial cells was also higher than that of normal endometrial cells. Moreover, TGF-β1 directly induced the adhesion of endometrial cells to mesothelial cells through the regulation of integrin of αV, α6, β1, and β4 via the activation of the TGF-β1/TGF-βRI/Smad2 signaling pathway. Conversely, the adhesion of TGF-β1-stimulated endometrial cells to mesothelial cells was clearly reduced following treatment with neutralizing antibodies against specific TGF-β1-mediated integrins αV, β1, and β4 on the endometrial cell membrane. Taken together, these results suggest that TGF-β1 may act to promote the initiation of endometriosis by enhancing integrin-mediated cell-cell adhesion.

Increased expression of resistin in ectopic endometrial tissue of women with endometriosis

PROBLEM

Inflammation is a key process in the establishment and progression of endometriosis. Resistin, an adipocytokine, has biological properties linked to immunologic functions, but its role in endometriosis is unclear.

METHOD OF STUDY

Resistin gene expression was examined in eutopic and ectopic endometrial tissues from women with (n=25) or without (n=25) endometriosis. Resistin mRNA and protein levels were determined in endometrial tissue using quantitative real-time reverse transcription PCR and Western blotting, following adipokine profiling arrays.

RESULTS

Resistin protein was detected in human endometrial tissues using an adipokine array test. Resistin mRNA and protein levels were significantly higher in ectopic endometrial tissue of patients with endometriosis than in normal eutopic endometrial tissue.

CONCLUSION

Our results indicate that resistin is differentially expressed in endometrial tissues from women with endometriosis and imply a role for resistin in endometriosis-associated pelvic inflammation.

MicroRNA expression analysis in endometriotic serum treated mesenchymal stem cells

Endometriosis is defined by presence of endometrial-like-tissue outside the uterus. Recently, ectopic endometriotic lesions have been suggested to originate by abnormal differentiation of endometrial mesenchymal stem cells (eMSCs). MicroRNAs (miRNAs) play an important role in the pathophysiology of endometriosis. Through a PCR array approach, we aimed to assess the differential expression of microRNAs in human eMSC treated in culture with sera derived from women with severe endometriosis. Sera were collected from five patients with severe endometriosis and three control women and added individually in the culture medium to conduct experimental and control eMSC sets, respectively. Regular microscopic follow-up for cell morphology was performed. SYBR Green based real-time PCR array was used to assess the expression of 84 miRNAs. Bioinformatics analysis was done to predict the target genes of the significantly dysregulated miRNAs and their enriched biological processes and pathways. Thirty-two miRNAs were found significantly dysregulated in experimental cultures. Functional enrichment analysis revealed several endometriosis associated biological processes and pathways were enriched by target genes of these miRNAs. In conclusion, treatment of human eMSCs with sera of severe endometriosis cases affects the expression of certain miRNAs and their target genes. This may result in altering cell functions and consequently, endometriosis development.

High-throughput mRNA sequencing of stromal cells from endometriomas and endometrium

The aetiology of endometriosis is still unclear and to find mechanisms behind the disease development, it is important to study each cell type from endometrium and ectopic lesions independently. The objective of this study was to uncover complete mRNA profiles in uncultured stromal cells from paired samples of endometriomas and eutopic endometrium. High-throughput mRNA sequencing revealed over 1300 dysregulated genes in stromal cells from ectopic lesions, including several novel genes in the context of endometriosis. Functional annotation analysis of differentially expressed genes highlighted pathways related to cell adhesion, extracellular matrix-receptor interaction and complement and coagulation cascade. Most importantly, we found a simultaneous upregulation of complement system components and inhibitors, indicating major imbalances in complement regulation in ectopic stromal cells. We also performed in vitro experiments to evaluate the effect of endometriosis patients' peritoneal fluid (PF) on complement system gene expression levels, but no significant impact of PF on C3, CD55 and CFH levels was observed. In conclusion, the use of isolated stromal cells enables to determine gene expression levels without the background interference of other cell types. In the future, a new standard design studying all cell types from endometriotic lesions separately should be applied to reveal novel mechanisms behind endometriosis pathogenesis.

Endometriosis: Epidemiology, Diagnosis and Clinical Management

Purpose of review

Endometriosis is a disease of adolescents and reproductive-aged women characterized by the presence of endometrial tissue outside the uterine cavity and commonly associated with chronic pelvic pain and infertility. Here we review the epidemiology of endometriosis as well as potential biomarkers for detection and with the goal of highlighting risk factors that could be used in combination with biomarkers to identify and treat women with endometriosis earlier..

Recent findings

Early age at menarche, shorter menstrual length, and taller height are associated with a higher risk of endometriosis while parity, higher body mass index (BMI) and smoking are associated with decreased risk. Endometriosis often presents as infertility or continued pelvic pain despite treatment with analgesics and cyclic oral contraceptive pills.

Summary

Despite a range of symptoms, diagnosis of endometriosis is often delayed due to lack of non-invasive, definitive and consistent biomarkers for diagnosis of endometriosis. Hormone therapy and analgesics are used for treatment of symptomatic endometriosis. However, the efficacy of these treatments are limited as endometriosis often recurs. In this review, we describe potential diagnostic biomarkers and risk factors that may be used as early non-invasive in vitro tools for identification of endometriosis to minimize diagnostic delay and improve reproductive health of patients.

Syndecan-4 expression is upregulated in endometriosis and contributes to an invasive phenotype

OBJECTIVE

To study the expression and function of syndecan-4 in endometriosis.

DESIGN

Histopathological investigation of eutopic endometrium and experimental laboratory study on a cell line derived from epithelial endometriotic cells (12Z).

SETTING

University hospital laboratory.

PATIENT(S)

One hundred six women (62 controls/44 endometriosis) from the IVF center of Münster University Hospital aged 23-44 undergoing Pipelle biopsy and diagnostic exploratory laparoscopy.

INTERVENTION(S)

Eutopic endometrial tissue was investigated by immunohistochemistry for the expression of syndecan-4. The human endometriotic cell line 12Z was transiently transfected with syndecan-4 small interfering RNA and investigated for changes in cell behavior.

MAIN OUTCOME MEASURE(S)

Syndecan-4 expression in eutopic endometrium was evaluated immunohistochemically in endometrial glands and stroma. Scoring results were correlated with the stages of the menstrual cycle and presence or absence of endometriosis. Quantitative polymerase chain reaction was used to measure syndecan-4-dependent expression changes of MMP2, MMP3, MMP9, Rac1, and ATF2. Altered cell behavior was monitored by matrigel invasion assays and cell viability assays.

RESULT(S)

Syndecan-4 expression was significantly higher in the glands and stroma of patients with endometriosis compared with controls, whereas no menstrual cycle-dependent expression was observed. In 12Z cells, syndecan-4 depletion did not affect cell viability but resulted in a significantly reduced matrigel invasiveness and reduced expression of the small GTPase Rac1, the transcription factor ATF-2, and MMP3.

CONCLUSION(S)

The upregulation of syndecan-4 in the eutopic endometrium of endometriosis patients may facilitate the pathogenetic process by promoting invasive cell growth via Rac1, MMP3, and ATF-2.

Enhanced inflammatory activity of endometriotic lesions from the rectovaginal septum

Endometriosis is characterised by the growth of ectopic lesions at multiple locations outside the uterine cavity and may be considered a collection of distinct but related conditions. The exact aetiology of endometriosis is still not clear although a role for inflammation is increasingly accepted. We therefore investigated the inflammatory activity of eutopic tissue and that of the matching ectopic lesions from different locations by measuring the genetic expression of inflammatory chemokines and cytokines. The gene expression in matching eutopic and ectopic tissue was compared, as was the gene expression in lesions from different locations. A significantly higher mRNA expression of the chemokines ENA-78 and RANTES and the cytokines IL-6 and TNFα was observed in endometriotic lesions of the rectovaginal septum (RVS) compared to that of matching eutopic tissue. Comparisons across lesion locations showed a significantly higher expression of IL-6 and TNFα in the RVS compared to lesions from either the ovaries or the peritoneum. These results show that the production of some inflammatory chemokines and cytokines is significantly increased in the ectopic endometrial tissue compared to matching eutopic tissue. Furthermore, IL-6 and TNFα are produced in significantly higher quantities in RVS lesions compared to other lesions.

COUP-TFII regulates human endometrial stromal genes involved in inflammation

Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII; NR2F2) is an orphan nuclear receptor involved in cell-fate specification, organogenesis, angiogenesis, and metabolism. Ablation of COUP-TFII in the mouse uterus causes infertility due to defects in embryo attachment and impaired uterine stromal cell decidualization. Although the function of COUP-TFII in uterine decidualization has been described in mice, its role in the human uterus remains unknown. We observed that, as in mice, COUP-TFII is robustly expressed in the endometrial stroma of healthy women, and its expression is reduced in the ectopic lesions of women with endometriosis. To interrogate the role of COUP-TFII in human endometrial function, we used a small interfering RNA-mediated loss of function approach in primary human endometrial stromal cells. Attenuation of COUP-TFII expression did not completely block decidualization; rather it had a selective effect on gene expression. To better elucidate the role of COUP-TFII in endometrial stroma cell biology, the COUP-TFII transcriptome was defined by pairing microarray comparison with chromatin immunoprecipitation followed by deep sequencing. Gene ontology analysis demonstrates that COUP-TFII regulates a subset of genes in endometrial stroma cell decidualization such as those involved in cell adhesion, angiogenesis, and inflammation. Importantly this analysis shows that COUP-TFII plays a role in controlling the expression of inflammatory cytokines. The determination that COUP-TFII plays a role in inflammation may add insight into the role of COUP-TFII in embryo implantation and in endometrial diseases such as endometriosis.

RHOC: a key gene for endometriosis

Considerable efforts have been invested in elucidating the potential mechanisms involved in the physiopathology of endometriosis. The aims of our study were to investigate whether RHOC expression is differentially altered in the endometrium and in endometriotic lesions. A total of 40 patients diagnosed with endometriosis and 15 healthy fertile women were selected for the study. Paired biopsies of endometrial tissue (eutopic endometrium) and endometriotic lesions (ectopic endometrium) were obtained from the patients with endometriosis. Endometrium from women without endometriosis was used as a control. Expression of the RHOC gene was analyzed by real-time polymerase chain reaction in autologous endometrial tissues of women with endometriosis and in the endometrium of control women. Increased RHOC expression was detected in endometriotic lesions compared to the eutopic endometrium of women with endometriosis and control women. RHOC changes may be among the key elements involved in the origin and the maintenance of endometriosis.

Expression profile of extracellular matrix and adhesion molecules in the development of endometriosis in a mouse model

Ectopic endometrial tissue induces various reactions in surrounding tissues, such as the surface of the ovary and peritoneal cavity, leading to endometriosis. The aim of this study is to investigate the expression profile of extracellular matrix (ECM) and adhesion molecules in the early steps of development of experimental mouse endometriosis, specifically in peritoneum adjacent to endometrium transplants attached via autotransplantation. The endometriosis model was induced by autotransplantation of endometrium to peritoneal tissue. Peritoneal tissues adjacent to the transplant were obtained at 1, 4, and 7 days posttransplantation. The results showed that messenger RNA expression levels of most of the integrins, collagens, and other ECM reached a peak at 7 days posttransplantation. Uniquely, Lamc2 was significantly increased to its maximum level within 24 hours posttransplantation and may be strongly associated with initiation of the development of endometriosis. These data will be helpful in further investigations of the treatment of endometriosis.

Novel estrogen-related genes and potential biomarkers of ovarian endometriosis identified by differential expression analysis

In the search for novel biomarkers of endometriosis, we selected 152 genes from the GeneLogic database based on results of genome-wide expression analysis of ovarian endometriosis, plus 20 genes related to estrogen metabolism and action. We then performed low-density array analysis of these 172 genes on 11 ovarian endometriosis samples and 9 control endometrium samples. Principal component analysis of the gene expression levels showed clear separation between the endometriosis and control groups. We identified 78 genes as differentially expressed. Based on Ingenuity pathway analysis, these differentially expressed genes were arranged into groups according to biological function. These analyses revealed that 32 differentially expressed genes are estrogen related, 23 of which have not been reported previously in connection with endometriosis. Functional annotation showed that 25 and 22 genes are associated with the biological terms "secreted" and "extracellular region", respectively. Differential expression of 4 out of 5 genes related to estrogen metabolism and action (ESR1, ESR2, PGR and BGN) was also confirmed by immunohistochemistry. Our study thus reveals differential expression of several genes that have not previously been associated with endometriosis and that encode potential novel biomarkers and drug targets.

Peroxisome-proliferator activator receptor-gamma activation decreases attachment of endometrial cells to peritoneal mesothelial cells in an in vitro model of the early endometriotic lesion

The aim of this study was to investigate whether peroxisome proliferator-activated receptor (PPAR)-gamma activation has an effect on the attachment of endometrial cells to peritoneal mesothelial cells in a well-established in vitro model of the early endometriotic lesion. The endometrial epithelial cell line EM42 and mesothelial cell line LP9 were used for this study. EM42 cells, LP9 cells or both were treated with the PPAR-gamma agonist ciglitazone (CTZ) at varying concentrations (10, 20 and 40 microM) x 48 h with subsequent co-culture of EM42 and LP9 cells. The rate of EM42 attachment and invasion through LP9 cells was then assessed and compared with control (EM42 and LP9 cells co-cultured without prior treatment with CTZ). Next, attachment of CTZ-treated and untreated EM42 cells to hyaluronic acid (HA), a cell adhesion molecule (CAM) on peritoneal mesothelial cells, were assessed. Although there was no difference in EM42 attachment when LP9 cells alone were treated with CTZ, treatment of EM42 cells with 40 microM CTZ decreased EM42 attachment to LP9 cells by 27% (P < 0.01). Treatment of both EM42 and LP9 cells with 40 microM CTZ decreased EM42 attachment to LP9 by 37% (P < 0.01). Treatment of EM42 cells with 40 microM CTZ decreased attachment to HA by 66% (P = 0.056). CTZ did not decrease invasion of EM42 cells through the LP9 monolayer. CTZ may inhibit EM42 cell proliferation. In conclusion, CTZ significantly decreased EM42 attachment to LP9 cells and HA in an in vitro model of the early endometriotic lesion.

Proteomics technologies in endometriosis

Endometriosis is a common disorder that is associated with infertility and pelvic pain. Diagnosis is based on the visualization of endometriotic lesions during surgery as no reliable serum marker is currently available. The etiology of endometriosis is largely unknown. Over the last 20 years, several proteomics technologies have been used to research novel proteins with a potential etiological role in endometriosis, and to identify candidate serum markers for this condition. While some molecules identified by proteomics technologies may have a relevant role in the pathogenesis of endometriosis, the research of potential serum markers for this condition is still far from any clinical application. This review summarizes the state of the art and potential applications of proteomics in endometriosis research.

Alteration of focal adhesion kinase expression in eutopic endometrium of women with endometriosis

OBJECTIVE

To investigate whether focal adhesion kinase (FAK) expression is altered in eutopic endometrium of women with endometriosis.

DESIGN

Experimental study using human endometrial tissue.

SETTING

Academic research center.

PATIENT(S)

Women with or without endometriosis who were undergoing surgery for benign indications.

INTERVENTION(S)

Endometrial biopsy.

MAIN OUTCOME MEASURE(S)

Expression of FAK was assessed by immunohistochemistry, Western blotting analysis, and reverse-transcription polymerase chain reaction.

RESULT(S)

At secretory phase, the average level of endometrial FAK expression of women with endometriosis was significantly higher than that of controls, but no significant difference was found between the two groups at proliferative phase. There was a positive correlation between FAK expression in secretory endometrial tissues and disease stage and pelvic pain in women with endometriosis. Furthermore, the endometrial FAK protein expression varied with the serum E(2) at proliferative phase and with the ratio of E(2) to P at secretory phase.

CONCLUSION(S)

The study showed a significant increase of FAK expression in the secretory endometrial tissues of women with endometriosis, a relationship between FAK expression and disease stage, pelvic pain, and serum steroid hormones. Those results suggest that FAK may play a role in the pathogenesis of endometriosis and be regulated by steroid hormones.

Adhesion molecules changes at 20 gestation weeks in pregnancies complicated by preeclampsia

OBJECTIVES

To examine soluble E-selectin, L-selectin, P-selectin, ICAM-1, and VCAM-1 levels in normotensive and preeclamptic pregnancies. To determine cut-offs useful for preeclampsia early detection.

STUDY DESIGN

A cohort of nulliparous women was recruited at family medicine clinics in Mexico City. Preeclampsia developed in 75 patients; 125 normotensive controls were matched. Adhesion molecules were assessed in serum obtained at 20 gestation weeks and in third trimester pregnancies. Predictive values and odds ratios for preeclampsia development were calculated with the 20 gestation week results. Threshold values were selected based on ROC curves values.

RESULTS

In women with subsequent preeclampsia, sL-selectin and sVCAM-1 concentrations were significantly lower, whereas sE-selectin, sP-selectin and sICAM-1 levels were significantly higher, compared with controls at mid-pregnancy (p<0.05). The odds ratio for low sL-selectin was 25.6 (95% CI, 8.9-73.5; cut-off, 1414 ng/ml). The sensitivity, specificity, and positive and negative predictive values of low sL-selectin for preeclampsia development were 84, 90, 39, and 98%, respectively, whereas its sensitivity, specificity, and positive and negative predictive values for severe preeclampsia development (cut-off, 1210 ng/ml) were 100, 98, 60, and 100%, respectively.

CONCLUSIONS

Early enhanced activation of endothelial cells, platelets and leukocytes seem to be present in preeclamptic patients, especially in those that develop severe preeclampsia. Low sL-selectin levels at 20 gestation weeks may be an indicator of preeclampsia development.

The role of endometrium in endometriosis

Endometriosis is defined as the presence of endometrial glands and stroma outside the uterus. Several theories have been proposed to explain the pathogenesis of this disease. According to Sampson's retrograde menstruation theory, endometrial cells are refluxed through the fallopian tubes during the menstruation and implant onto peritoneum or pelvic organs. Since retrograde menstruation is a very common phenomenon among women of reproductive age, there must be other factors that may contribute to the pathophysiology and/or pathogenesis of endometriosis. Genetic predisposition, environmental factors, and alterations in immune and endocrine functions are believed to play significant roles in the establishment and maintenance of endometriosis. Although the eutopic endometriums of women with and without endometriosis are histologically similar, studies revealed that there are many fundamental differences between these two tissues. Invasive properties, decreased apoptosis, alterations in expression of specific gene and proteins, and increased steroid and cytokine production have been identified in eutopic endometrium of women with endometriosis. Furthermore, significant biochemical differences exist even between ectopic and autologous eutopic endometrium. These differences can be explained by the direct effects of an inflammatory peritoneal environment.