Altered gene expression and secretion of interleukin-6 in stromal cells derived from endometriotic tissues

Macrophage polarization in adenomyosis: A review

Adenomyosis (AM) is a common gynecological disorder characterized by the presence of endometrial glands and stroma within the uterine myometrium. It is associated with abnormal uterine bleeding (AUB), dysmenorrhea, and infertility. Although several mechanisms have been proposed to elucidate AM, the exact cause and development of the condition remain unclear. Recent studies have highlighted the significance of macrophage polarization in the microenvironment, which plays a crucial role in AM initiation and progression. However, a comprehensive review regarding the role and regulatory mechanism of macrophage polarization in AM is currently lacking. Therefore, this review aims to summarize the phenotype and function of macrophage polarization and the phenomenon of the polarization of adenomyosis-associated macrophages (AAMs). It also elaborates on the role and regulatory mechanism of AAM polarization in invasion/migration, fibrosis, angiogenesis, dysmenorrhea, and infertility. Furthermore, this review explores the underlying molecular mechanisms of AAM polarization and suggests future research directions. In conclusion, this review provides a new perspective on understanding the pathogenesis of AM and provides a theoretical foundation for developing targeted drugs through the regulation of AAM polarization.

Establishment of Immortalized Human Endometriotic Stromal Cell Line from Ectopic Lesion of a Patient with Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease characterized by the growth of endometrial-like tissues containing endometrial stromal cells and glandular epithelium outside the uterine cavity. An insufficient response to progesterone contributes to disease progression and systemic inflammation during the pathogenesis of endometriosis. Patients with endometriosis usually experience painful symptoms, dysmenorrhea, and infertility, which contribute to a significant reduction in their quality of life. To determine the possible molecular mechanisms of endometriosis and explore novel therapeutic targets, we derived primary human ovarian endometriotic stromal cells (hOESCs) from a patient of reproductive age with ovarian endometriosis. In this study, we successfully established immortalized human ovarian endometriotic stromal cell lines (ihOESCs) using primary stromal cells obtained from endometriotic lesions to overcome short lifespan and growth inhibition. Immortalization of hOESCs with human telomerase reverse transcriptase (hTERT) transfection led to cells that maintained a proliferative state under passage culture conditions without mutagenesis during cellular senescence. The morphology and karyotype of ihOESCs were unchanged compared with those of hOESCs. Moreover, ihOESCs were continuously positive for vimentin and negative for E-cadherin expression. Following decidual stimuli and inflammatory responses, both hOESCs and ihOESCs sensitively express decidualization markers and proinflammatory cytokines. Collectively, we characterized ihOESCs to maintain their phenotypic and functional properties with a longer lifespan and normal physiological responses than those of hOESCs. These immortalized cells could aid in a detailed understanding of the pathological mechanisms of endometriosis.

IL-10 is not anti-fibrotic but pro-fibrotic in endometriosis: IL-10 treatment of endometriotic stromal cells in vitro promotes myofibroblast proliferation and collagen type I protein expression

STUDY QUESTION

Is interleukin-10 (IL-10) anti-fibrotic in endometriosis?

SUMMARY ANSWER

IL-10 is not anti-fibrotic but pro-fibrotic in endometriosis, because IL-10 treatment of endometriotic stromal cells in vitro promotes myofibroblast proliferation and collagen type I protein expression.

WHAT IS KNOWN ALREADY

We previously showed that persistent activation of signal transducer and activator of transcription 3 (STAT3) via IL-6 trans-signaling promotes fibrosis of endometriosis. Studies showed marked anti-fibrotic effects of IL-10 via the STAT3 signaling pathway, which is generally considered to be anti-inflammatory, in various organs.

STUDY DESIGN, SIZE, DURATION

Endometrial and/or endometriotic samples of 54 patients who had histological evidence of deep endometriosis, and endometrial samples from 30 healthy fertile women were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The effects of IL-10/STAT3 signaling as well as inhibition of STAT3 activation by knockdown of STAT3 gene on the pro-fibrotic phenotype in endometrial and endometriotic stromal cells in vitro were investigated. Then, the effects of various time points of IL-10 treatment in combination with transforming growth factor (TGF)-β1 and/or IL-6/soluble IL-6 receptor (sIL-6R) on the profibrotic phenotype of endometrial and endometriotic stromal cells were investigated.

MAIN RESULTS AND THE ROLE OF CHANCE

IL-10 induced pro-fibrotic phenotype (cell proliferation, collagen type I synthesis, α-smooth muscle actin positive stress fibers and collagen gel contraction) of endometriotic stromal cells. Knockdown of STAT3 gene decreased the IL-10 induced pro-fibrotic phenotype of endometriotic stromal cells. In contrast, IL-10 had no significant effects on pro-fibrotic phenotype of endometrial stromal cells of healthy women. Sequential IL-10 treatment with or without TGF-β1 and/or IL-6/sIL-6R induced persistent activation of STAT3 and significantly increased proliferation of myofibroblasts (cells with α-smooth muscle actin positive stress fibers) and protein expression of collagen type I in endometriotic stromal cells. TGF-β1 and/or IL-6/sIL6RIL-6/sIL6R treatment significantly increased tissue inhibitor of metalloproteinase 1 (TIMP1) protein expression, whereas IL-10 had no significant effects. Knockdown of STAT3 gene significantly decreased the TGF-β1 and/or IL-6/sIL6R induced TIMP1 protein expression. In contrast, pre-treatment with IL-10 before TGF-β1 and/or IL-6/sIL-6R treatment and sequential IL-10 treatment with or without TGF-β1 and/or IL-6/sIL-6R significantly decreased proliferation of fibroblasts (cells without α-smooth muscle actin positive stress fibers) and collagen type I protein expression in endometrial stromal cells of healthy women.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Given the large number of complex interactions and signaling pathways of pro- and anti-inflammatory mediators that are involved in the pathophysiology of endometriosis, the present study investigated only a very small portion of the whole. Further in vivo studies are required to validate the present findings.

WIDER IMPLICATIONS OF THE FINDINGS

Inflammatory mediators in the pathophysiology of endometriosis have been extensively investigated as potential therapeutic targets. However, the present study showed that anti-inflammatory signals of IL-10 and IL-6 through persistent STAT3 activation may promote endometriosis fibrosis. Therapeutic strategies, such as suppression of 'inflammation', might dysregulate the cross-regulation of 'pro- and anti-inflammatory mediators', leading to detrimental effects in patients with endometriosis, such as fibrosis. To develop new, but not deleterious, therapeutic strategies, studies are required to investigate whether, how and what 'anti-inflammatory mediators' along with pro-inflammatory mediators are involved in individual patients with endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported in part by KARL STORZ SE & Co. KG (Tuttlingen, Germany). The authors have no conflict of interest to disclose.

Gene expression analysis in endometriosis: Immunopathology insights, transcription factors and therapeutic targets

Background

Endometriosis is recognized as an estrogen-dependent inflammation disorder, estimated to affect 8%-15% of women of childbearing age. Currently, the etiology and pathogenesis of endometriosis are not completely clear. Underlying mechanism for endometriosis is still under debate and needs further exploration. The involvement of transcription factors and immune mediations may be involved in the pathophysiological process of endometriosis, but the specific mechanism remains to be explored. This study aims to investigate the underlying molecular mechanisms in endometriosis.

Methods

The gene expression profile of endometriosis was obtained from the gene expression omnibus (GEO) database. Gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA) were applied to the endometriosis GSE7305 datasets. Cibersort and MCP-counter were used to explore the immune response gene sets, immune response pathway, and immune environment. Differentially expressed genes (DEGs) were identified and screened. Common biological pathways were being investigated using the kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis. Transcription factors were from The Human Transcription Factors. The least absolute shrinkage and selection operator (Lasso) model identified four differential expressions of transcription factors (AEBP1, HOXB6, KLF2, and RORB). Their diagnostic value was calculated by receiver operating characteristic (ROC) curve analysis and validated in the validation cohort (GSE11691, GSE23339). By constructing the interaction network of crucial transcription factors, weighted gene coexpression network analysis (WGCNA) was used to search for key module genes. Metascape was used for enrichment analysis of essential module genes and obtained HOXB6, KLF2. The HOXB6 and KLF2 were further verified as the only two intersection genes according to Support Vector Machine Recursive Feature Elimination (SVM-RFE) and random forest models. We constructed ceRNA (lncRNA-miRNA-mRNA) networks with four potential transcription factors. Finally, we performed molecular docking for goserelin and dienogest with four transcription factors (AEBP1, HOXB6, KLF2, and RORB) to screen potential drug targets.

Results

Immune and metabolic pathways were enriched in GSVA and GSEA. In single sample gene set enrichment analysis (ssGSEA), most immune infiltrating cells, immune response gene sets, and immune response pathways are differentially expressed between endometriosis and non-endometriosis. Twenty-seven transcription factors were screened from differentially expressed genes. Most of the twenty-seven transcription factors were correlated with immune infiltrating cells, immune response gene sets and immune response pathways. Furthermore, Adipocyte enhancer binding protein 1 (AEBP1), Homeobox B6 (HOXB6), Kruppel Like Factor 2 (KLF2) and RAR Related Orphan Receptor B (RORB) were selected out from twenty-seven transcription factors. ROC analysis showed that the four genes had a high diagnostic value for endometriosis. In addition, KLF2 and HOXB6 were found to play particularly important roles in multiple modules (String, WGCNA, SVM-RFE, random forest) on the gene interaction network. Using the ceRNA network, we found that NEAT1 may regulate the expressions of AEBP1, HOXB6 and RORB, while X Inactive Specific Transcript (XIST) may control the expressions of HOXB6, RORB and KLF2. Finally, we found that goserelin and dienogest may be potential drugs to regulate AEBP1, HOXB6, KLF2 and RORB through molecular docking.

Conclusions

AEBP1, HOXB6, KLF2, and RORB may be potential biomarkers for endometriosis. Two of them, KLF2 and HOXB6, are critical molecules in the gene interaction network of endometriosis. Discovered by molecular docking, AEBP1, HOXB6, KLF2, and RORB are targets for goserelin and dienogest.

The Phytochemical Profile and Biological Activity of Malva neglecta Wallr. in Surgically Induced Endometriosis Model in Rats

Leaves and aerial parts of Malva neglecta Wallr. have been traditionally used in Anatolia for the treatment of pain, inflammation, hemorrhoids, renal stones, constipation, and infertility. This study investigated the effects of M. neglecta leaves in a rat endometriosis model. The dried plant material was extracted with n-hexane, ethyl acetate, and methanol, successively. Experimental endometriosis was surgically induced in six-week-old female, non-pregnant, Wistar albino rats by autotransplant of endometrial tissue to the abdominal wall. After twenty-eight days, rats were evaluated for a second laparotomy. Endometrial foci areas were assessed, and intraabdominal adhesions were scored. Rats were divided into five groups as control, n-hexane, ethyl acetate, methanol, and aqueous extracts, as well as reference. At the end of the treatment, all rats were sacrificed and endometriotic foci areas and intraabdominal adhesions were re-evaluated and compared with the previous findings. Moreover, peritoneal fluid was collected to detect tumor necrosis factor- α (TNF-α), vascular endothelial growth factor (VEGF), and interleukin-6 (IL-6) levels, and cDNA synthesis, and a quantitative real-time polymerase chain reaction (PCR) test was done. The phytochemical content of the most active extract was determined using High-Performance Liquid Chromatography (HPLC). Both endometrial volume and adhesion score decreased significantly in the group treated with methanol extract. In addition, significant decreases were observed in TNF-α, VEGF, and IL-6 levels in animals administered methanol extract. HPLC results showed that the activity caused by the methanol extract of M. neglecta was due to the polyphenols. Taken together, these novel findings indicate that M. neglecta may be a promising alternative for the treatment of endometriosis.

Effects of risk factors for ovarian cancer in women with and without endometriosis

OBJECTIVE

To evaluate the associations between 10 well-established ovarian cancer risk factors and risk of ovarian cancer among women with vs. without endometriosis.

DESIGN

Pooled analysis of 9 case-control studies in the Ovarian Cancer Association Consortium.

SETTING

Population-based.

PATIENT(S)

We included 8,500 women with ovarian cancer, 13,592 control women.

INTERVENTION(S)

Ten well-established ovarian cancer risk factors.

MAIN OUTCOME MEASURE(S)

Risk of ovarian cancer for women with and without endometriosis.

RESULT(S)

Most risk factor-ovarian cancer associations were similar when comparing women with and without endometriosis, and no interactions were statistically significant. However, body mass index (BMI) 25-<30 kg/m² was associated with increased ovarian cancer risk among women with endometriosis (odds ratio [OR] = 1.27, 95% confidence interval [CI] 1.00-1.60), but not associated with the risk among women without endometriosis (OR = 0.97; 95% CI, 0.91-1.05) when compared with BMI 18.5-<25 kg/m²; an increased risk was observed for a BMI ≥30 kg/m², although there was little difference comparing women with endometriosis (OR = 1.21; 95% CI, 0.94-1.57) to women without (OR = 1.13; 95% CI, 1.04-1.22) (P-interaction = .51). Genital talcum powder use and long-term menopausal estrogen-only therapy use showed increased ovarian cancer risk, but risk appeared greater for those with endometriosis vs. those without (genital talcum powder: OR = 1.38; 95% CI, 1.04-1.84 vs. OR = 1.12; 95% CI, 1.01-1.25, respectively; ≥10 years of estrogen-only therapy: OR = 1.88; 95% CI, 1.09-3.24 vs. OR = 1.42; 95% CI, 1.14-1.76, respectively); neither of these interactions were statistically significant (P-interaction = .65 and P-interaction = .96, respectively).

CONCLUSION(S)

The associations between ovarian cancer and most risk factors were similar among women with and without endometriosis. However, there was some suggestion of differences by endometriosis status for BMI, menopausal hormone therapy use, and genital talcum powder use, highlighting the complexity of ovarian cancer etiology.

Roles of microRNAs in Regulating Apoptosis in the Pathogenesis of Endometriosis

Endometriosis is a gynecologic disorder characterized by the presence of endometrial tissues outside the uterine cavity affecting reproductive-aged women. Previous studies have shown that microRNAs and their target mRNAs are expressed differently in endometriosis, suggesting that this molecule may play a role in the development and persistence of endometriotic lesions. microRNA (miRNA), a small non-coding RNA fragment, regulates cellular functions such as cell proliferation, differentiation, and apoptosis by the post-transcriptional modulation of gene expression. In this review, we focused on the dysregulated miRNAs in women with endometriosis and their roles in the regulation of apoptosis. The dysregulated miRNAs and their target genes in this pathophysiology were highlighted. Circulating miRNAs as potential biomarkers for the diagnosis of endometriosis have also been identified. As shown by various studies, miRNAs were reported to be a potent regulator of gene expression in endometriosis; thus, identifying the dysregulated miRNAs and their target genes could help discover new therapeutic targets for treating this disease. The goal of this review is to draw attention to the functions that miRNAs play in the pathophysiology of endometriosis, particularly those that govern cell death.

Epigenetic regulation and T-cell responses in endometriosis – something other than autoimmunity

Endometriosis is defined as the presence of endometrial-like glands and stroma located outside the uterine cavity. This common, estrogen dependent, inflammatory condition affects up to 15% of reproductive-aged women and is a well-recognized cause of chronic pelvic pain and infertility. Despite the still unknown etiology of endometriosis, much evidence suggests the participation of epigenetic mechanisms in the disease etiopathogenesis. The main rationale is based on the fact that heritable phenotype changes that do not involve alterations in the DNA sequence are common triggers for hormonal, immunological, and inflammatory disorders, which play a key role in the formation of endometriotic foci. Epigenetic mechanisms regulating T-cell responses, including DNA methylation and posttranslational histone modifications, deserve attention because tissue-resident T lymphocytes work in concert with organ structural cells to generate appropriate immune responses and are functionally shaped by organ-specific environmental conditions. Thus, a failure to precisely regulate immune cell transcription may result in compromised immunological integrity of the organ with an increased risk of inflammatory disorders. The coexistence of endometriosis and autoimmunity is a well-known occurrence. Recent research results indicate regulatory T-cell (Treg) alterations in endometriosis, and an increased number of highly active Tregs and macrophages have been found in peritoneal fluid from women with endometriosis. Elimination of the regulatory function of T cells and an imbalance between T helper cells of the Th1 and Th2 types have been reported in the endometria of women with endometriosis-associated infertility. This review aims to present the state of the art in recognition epigenetic reprogramming of T cells as the key factor in the pathophysiology of endometriosis in the context of T-cell-related autoimmunity. The new potential therapeutic approaches based on epigenetic modulation and/or adoptive transfer of T cells will also be outlined.

Intricate Connections between the Microbiota and Endometriosis

Imbalances in gut and reproductive tract microbiota composition, known as dysbiosis, disrupt normal immune function, leading to the elevation of proinflammatory cytokines, compromised immunosurveillance and altered immune cell profiles, all of which may contribute to the pathogenesis of endometriosis. Over time, this immune dysregulation can progress into a chronic state of inflammation, creating an environment conducive to increased adhesion and angiogenesis, which may drive the vicious cycle of endometriosis onset and progression. Recent studies have demonstrated both the ability of endometriosis to induce microbiota changes, and the ability of antibiotics to treat endometriosis. Endometriotic microbiotas have been consistently associated with diminished Lactobacillus dominance, as well as the elevated abundance of bacterial vaginosis-related bacteria and other opportunistic pathogens. Possible explanations for the implications of dysbiosis in endometriosis include the Bacterial Contamination Theory and immune activation, cytokine-impaired gut function, altered estrogen metabolism and signaling, and aberrant progenitor and stem-cell homeostasis. Although preliminary, antibiotic and probiotic treatments have demonstrated efficacy in treating endometriosis, and female reproductive tract (FRT) microbiota sampling has successfully predicted disease risk and stage. Future research should aim to characterize the "core" upper FRT microbiota and elucidate mechanisms behind the relationship between the microbiota and endometriosis.

Resveratrol treatment reduces expression of MCP-1, IL-6, IL-8 and RANTES in endometriotic stromal cells

Endometriosis is an inflammatory disease affecting reproductive‐aged women. Immunologic disturbance, as well as inflammation, have crucial roles in the pathogenesis of endometriosis. In this study, we evaluated the effects of resveratrol treatment on expression of monocyte chemotactic protein‐1 (MCP‐1), interleukin‐6 (IL‐6), IL‐8, and regulated upon activation, normal T cell expressed and secreted (RANTES) in endometrial stromal cells from patients with endometriosis compared with non‐endometriotic controls. Thirteen eutopic (EuESCs) and nine ectopic (EESCs) endometrial stromal cells from endometriotic patients as well as eleven endometrial stromal cells from non‐endometriotic controls (CESCs) were treated with resveratrol (100 μmol/L) or ethanol, and gene and/or protein expression of MCP‐1, IL‐6, IL‐8 and RANTES was examined at 6, 24 and 48 hours following treatment in the cells from all origins. Resveratrol treatment significantly reduced gene and protein expression of MCP‐1, IL‐6, and IL‐8 in EuESCs and EESCs compared with CESCs (P < .05‐.001, P < .05‐.001 and P < .05‐<.01, respectively), and this reduction was more noticeable in EESCs than EuESCs (P < .05‐<.001). Besides, resveratrol treatment significantly reduced RANTES protein expression in EESCs in all time intervals (P < .05). Resveratrol treatment significantly reduced the expression of MCP‐1, IL‐6, IL‐8 and RANTES in EESCs.

Purinergic Signaling in Endometriosis-Associated Pain

Endometriosis is an estrogen-dependent gynecological disease, with an associated chronic inflammatory component, characterized by the presence of endometrial tissue outside the uterine cavity. Its predominant symptom is pain, a condition notably altering the quality of life of women with the disease. This review is intended to exhaustively gather current knowledge on purinergic signaling in endometriosis-associated pain. Altered extracellular ATP hydrolysis, due to changes in ectonucleotidase activity, has been reported in endometriosis; the resulting accumulation of ATP in the endometriotic microenvironment points to sustained activation of nucleotide receptors (P2 receptors) capable of generating a persistent pain message. P2X3 receptor, expressed in sensory neurons, mediates nociceptive, neuropathic, and inflammatory pain, and is enrolled in endometriosis-related pain. Pharmacological inhibition of P2X3 receptor is under evaluation as a pain relief treatment for women with endometriosis. The role of other ATP receptors is also discussed here, e.g., P2X4 and P2X7 receptors, which are involved in inflammatory cell–nerve and microglia–nerve crosstalk, and therefore in inflammatory and neuropathic pain. Adenosine receptors (P1 receptors), by contrast, mainly play antinociceptive and anti-inflammatory roles. Purinome-targeted drugs, including nucleotide receptors and metabolizing enzymes, are potential non-hormonal therapeutic tools for the pharmacological management of endometriosis-related pain.

Expression of monocyte chemotactic protein 2 and tumor necrosis factor alpha in human normal endometrium and endometriotic tissues

Endometriosis is a gynocological disease characterized by the presence of the endometrial glands and stroma outside the uterine cavity. This disease affects % 6-10 of women with reproductive age and it causes serious problems such as pelvic pain, dysmenorrhea and infertility. Although endometriosis is one of the most investigated disease of gynecology, its pathogenesis is not clear completely. In recent years, many studies revealed the inflammatory nature of endometriosis. Many of the immune cells and their secretory products cytokines and chemokines has been detected in body fluids of women with endometriosis. Cytokines are protein or glycoprotein in structures and hormon-like molecules that act generally in a paracrine fashion to regulate immun responses. They involved in chemotaxis, cell proliferation, cell activation, motility, adhesion and morphogenesis. Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine secreted by the macrophages, monocytes, neutrophiles, T cells and natural killer cells. It stimulates increase in the level of the chemokines in body fluids. Monocyte chemotactic protein 2 (MCP-2) is a chemokine act to recruit and activate monocytes into sites of inflammation area. The aim of this study to investigate the ultrastructural properties and whether the expression and localization of TNF-α and MCP-2 in the eutopic endometrium (normal endometrium of women with endometriosis) and endometritic tissues of women with endometriosis. Eutopic endometrial and endometriotic tissue samples were obtained from women with endometriosis between 20-41 y and normal endometrial tissues were collected from 5 women without endometriosis as a control group. Tissues were processed for light and electron microscopy and examined. The epithelial cells of endometriotic tissues were revealed strongly cytoplasmic TNF-α and MCP-2 immunreactivities. Eutopic endometrial tissues were also stained prominently for both TNF-α and MCP-2. Furthermore, a significant increase in stromal macrophages were observed in endometriotic tissues. Moreover, the ultrastructural observations on the normal and endometriotic tissues were exhibited microvilli-rich cells and ciliated cells. These findings suggest that TNF-α and MCP-2 may be involved in normal endometrial biology and in the pathogenesis of endometriosis.

Pyrvinium pamoate induces in-vitro suppression of IL-6 and IL-8 produced by human endometriotic stromal cells

Endometriosis, a chronic inflammatory disease, is identified by the presence of endometrial tissue outside the uterus. The prevalence of this disease among reproductive-age women is almost 10-15%. High levels of IL-6 and IL-8 have been found in the peritoneal fluid (PF) of women with endometriosis and are involved in its pathogenesis. Isolated stromal cells from 12 ectopic and eutopic endometrial biopsies of women with ovarian endometrioma and also 12 endometrial biopsies of nonendometriotic controls were treated with 1.1 µM pyrvinium pamoate, a Wnt/β-catenin signaling pathway inhibitor, for 72 hrs. Before treatment, mRNA gene expression and secretion of IL-6 and IL-8 were significantly higher in ectopic (EESCs) than eutopic (EuESCs) and control (CESCs) endometrial stromal cells. After treatment, mRNA gene expression and also secretion of IL-6 and IL-8 were significantly reduced. Our Findings showed that pyrvinium pamoate suppresses the mRNA gene expression and secretion of IL-6 and IL-8 in human endometriotic stromal cells. Additional investigations on this compound are required before clinical application.

MicroRNAs in endometriosis: biological function and emerging biomarker candidates†

MicroRNAs (miRNAs), a class of small noncoding RNA molecules, have been recognized as key post-transcriptional regulators associated with a multitude of human diseases. Global expression profiling studies have uncovered hundreds of miRNAs that are dysregulated in several diseases, and yielded many candidate biomarkers. This review will focus on miRNAs in endometriosis, a common chronic disease affecting nearly 10% of reproductive-aged women, which can cause pelvic pain, infertility, and a myriad of other symptoms. Endometriosis has delayed time to diagnosis when compared to other chronic diseases, as there is no current accurate, easily accessible, and noninvasive tool for diagnosis. Specific miRNAs have been identified as potential biomarkers for this disease in multiple studies. These and other miRNAs have been linked to target genes and functional pathways in disease-specific pathophysiology. Highlighting investigations into the roles of tissue and circulating miRNAs in endometriosis, published through June 2018, this review summarizes new connections between miRNA expression and the pathophysiology of endometriosis, including impacts on fertility. Future applications of miRNA biomarkers for precision medicine in diagnosing and managing endometriosis treatment are also discussed.

Enhanced local and systemic inflammatory cytokine mRNA expression in women with endometriosis evokes compensatory adaptive regulatory mRNA response that mediates immune suppression and impairs cytotoxicity

PROBLEM

Endometriosis is a disease characterized by ectopic implantation of endometrium and impaired immune responses. To explore its pathogenic mechanisms, we studied the local and systemic cytokine mRNA profiles and their role in the immunity of patients with endometriosis and healthy controls.

METHOD OF STUDY

mRNA for eleven cytokines defining cytotoxic Th1, humoral Th2, regulatory Tr1/Th3, and inflammatory cytokine profiles was characterized locally in endometriotic tissue and endometrium, and systemically in PBMCs from women with endometriosis and healthy controls, using real-time qRT-PCR. In addition, immunohistochemical stainings with monoclonal antibodies were performed looking for T regulatory cells in endometriotic lesions.

RESULTS

We found a downregulation of mRNA for cytokines mediating cytotoxicity and antibody response and an upregulation of inflammatory and T-regulatory cytokines in the endometriotic tissues and endometrium from the patients with endometriosis, suggesting enhanced local inflammation and priming of an adaptive regulatory response. Consistent with those findings, there was an abundancy of T regulatory cells in the endometriotic lesions.

CONCLUSIONS

The ectopic implantation seen in endometriosis could be possible as a consequence of increased inflammation and priming of adaptive T regulatory cells, resulting in impaired cytotoxicity and enhanced immune suppression.

Endometrial stromal cells treated by tumor necrosis factor-α stimulate macrophages polarized toward M2 via interleukin-6 and monocyte chemoattractant protein-1

AIM

This study aimed to investigate the effects of endometrial stromal cells (ESC)-derived interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 on macrophage polarization in endometriosis.

METHODS

Macrophage polarization was measured in eutopic endometrium of control participants ('normal endometrium'), eutopic endometrium of patients with endometriosis ('eutopic endometrium') and ectopic endometrium of endometriosis patients ('ectopic endometrium') by immunohistochemical staining. Expression of IL-6 and MCP-1 were measured in the eutopic and ectopic endometrium through enzyme-linked immunosorbent assays. Expression of CD163 was measured in human acute monocytic leukemia (THP-1) cell-derived macrophages that were treated with conditional medium induced by tumor necrosis factor (TNF)-α, TNF-α + anti-IL-6 or TNF-α + anti-MCP-1 via flow cytometry.

RESULTS

The ratio of CD163+/CD68+ macrophages in the normal endometrium was higher than that in the eutopic endometrium, while differences between the eutopic and ectopic endometrium were not statistically significant. IL-6 and MCP-1 exhibited enhanced expression in the ectopic endometrium group and decreased expression in the eutopic endometrium group. TNF-α could promote the expression of ESC-derived IL-6 and MCP-1. Intervention with TNF-α-induced conditioned medium resulted in the upregulation of CD163 in THP-1 cells, while conditional medium induced with IL-6 and MCP-1 neutralizing antibodies decreased the proportion of CD163+ macrophages significantly.

CONCLUSION

In endometriosis patients, the macrophages of the eutopic endometrium polarize toward M1 compared with the normal endometrium, and those of the ectopic endometrium were mainly M2-polarized. Under the action of TNF-α, ESC-derived IL-6 and MCP-1 could stimulate peritoneal macrophages toward M2-polarization, which could modulate endometriosis.

Progesterone and Estrogen Signaling in the Endometrium: What Goes Wrong in Endometriosis?

In the healthy endometrium, progesterone and estrogen signaling coordinate in a tightly regulated, dynamic interplay to drive a normal menstrual cycle and promote an embryo-receptive state to allow implantation during the window of receptivity. It is well-established that progesterone and estrogen act primarily through their cognate receptors to set off cascades of signaling pathways and enact large-scale gene expression programs. In endometriosis, when endometrial tissue grows outside the uterine cavity, progesterone and estrogen signaling are disrupted, commonly resulting in progesterone resistance and estrogen dominance. This hormone imbalance leads to heightened inflammation and may also increase the pelvic pain of the disease and decrease endometrial receptivity to embryo implantation. This review focuses on the molecular mechanisms governing progesterone and estrogen signaling supporting endometrial function and how they become dysregulated in endometriosis. Understanding how these mechanisms contribute to the pelvic pain and infertility associated with endometriosis will open new avenues of targeted medical therapies to give relief to the millions of women suffering its effects.

Human endometriotic lesion expression of the miR-144-3p/miR-451a cluster, its correlation with markers of cell survival and origin of lesion content

Endometriosis is an inflammatory condition in which endometrial tissue grows in ectopic locations. Survival and growth of these ectopic lesions is associated with pain and infertility. MicroRNAs (miRNAs) have been postulated to play a role in the pathophysiology of the disease and we have previously demonstrated expression of miR-451 in human endometriotic lesion tissue. Here we report elevated expression of the miR-144-3p/miR-451a cluster in human endometriotic lesion tissue. Use of an endometriotic epithelial cell line (12Z) in which the miRNA processing enzyme, DROSHA, was knocked down resulted in an enrichment in the primary (pri) form of miR-144-3p but not that of pri-miR-451a. Using an experimental mouse model of endometriosis in which ectopic endometriotic lesions were deficient for both of these miRNAs revealed that miR-451a, but not miR-144-3p may be derived from exogenous sources such as the circulation/erythrocytes. Together, these data suggest that the miR-144-3p/miR-451a cluster is expressed in human endometriotic lesion tissue, the level of expression correlates with survival status of the lesion tissue and that miR-451a, but not miR-144-3p may be derived from exogenous sources such as erythrocytes.

Serum and Ectopic Endometrium from Women with Endometriosis Modulate Macrophage M1/M2 Polarization via the Smad2/Smad3 Pathway

Objective

This study investigated the alterations in macrophage polarization in patients with endometriosis as well as the underlying molecular mechanisms.

Methods

Peritoneal washings, serum samples, and endometrial tissues were collected from endometriosis patients and control subjects. Endometrial stromal cells (ESCs) were isolated from endometrial tissue, and conditioned medium was prepared by treating ESCs with or without various concentrations of interleukin- (IL-) 6, estrogen, or progestin. The frequencies of CD86+ and CD163+ cells and expression levels of these markers as well as the cytokines IL-12 and IL-10 were measured in THP-1- (human monocytic leukemia cell) derived macrophages.

Results

There was a decrease in the percentage of CD86+ macrophages in the peritoneal wash solution of patients with endometriosis. Ectopic endometrial homogenates could promote M1 to M2 macrophage polarization in response to lipopolysaccharide (LPS), as evidenced by the increased percentage of CD163+ macrophages and increased IL-10 expression as well as a decreased percentage of CD86+ cells and lower IL-12 expression. In contrast, addition of serum from women with endometriosis to THP-1 cells resulted in the polarization of macrophages towards both M1 and M2 phenotypes. Upregulation of Smad2/Smad3 in macrophages upon exposure to eutopic and ectopic endometrial homogenates as well as serum of women with endometriosis was observed, and blockage of Smad2/Smad3 with their inhibitor SB431542 could reverse the macrophage polarization from M1 to M2. Conditioned medium induced by IL-6, but neither estrogen nor progestin, could facilitate M2 polarization. Neutralization of IL-6 diminished macrophage M2 polarization in endometriosis.

Conclusion

This study provides detailed evidence supporting alterations in M1 to M2 macrophage polarization that may contribute to the initiation as well as progression of endometriosis.

Expression of inflammatory cytokines in serum and peritoneal fluid from patients with different stages of endometriosis

OBJECTIVE

To investigate the level of inflammatory cytokines in endometriosis patients, and explore the relationship between IL-37 concentration and endometriosis stages.

METHODS

Inflammatory cytokine concentrations from 27 patients with different stages of endometriosis and 52 controls without endometriosis were examined by ELISA. Then, the specificity and sensitivity of cytokines for distinguishing from controls and the different stages of endometriosis were analyzed using the ROC curve.

RESULTS

The difference in serum concentrations of IL-37, IL-17A, IL-10, and IL-2 between the endometriosis and control groups was statistically significant (p < .01). Compared with controls, significantly higher levels of serum IL-37 and IL-10, and significantly lower levels of serum IL-17A and IL-2 were detected in patients with endometriosis (p < .01). Furthermore, IL-2 concentration was significantly higher in peritoneal fluid (PF) in the endometriosis group (p = .0034), IL-10 concentrations in PF were significantly lower in the early-stages of endometriosis than in the more advanced groups (p = .0439), and IL-4 concentration in PF was significantly higher in more advanced endometriosis (p = .0228). The sensitivity and specificity of serum IL-37 for distinguishing endometriosis were 81.48% and 83.33%, respectively, and the cutoff concentration was 69.84 pg/ml. For IL-17A, the sensitivity and specificity were 96.30% and 100%, respectively, and the cutoff concentration was 57.54 pg/ml. For IL-10, the sensitivity and specificity was 92.59% and 100%, respectively, and the cutoff concentration was 3.301 pg/ml. For IL-2, the sensitivity and specificity were 74.07% and 93.75%, respectively, and the cutoff concentration was 1.813 pg/ml. For PF IL-2, the sensitivity and specificity were 29.73% and 100%, respectively, and the cutoff concentration was 1.06 pg/ml.

CONCLUSIONS

IL-37, IL-17A, IL-10, and IL-2 may play a significant role in immune response in endometriosis. IL-37 levels may be used as a diagnostic marker for endometriosis.

Effect of simvastatin on baboon endometriosis

Endometriosis, a common disorder affecting women of reproductive age, is characterized by ectopic growth of the endometrial tissues, altered steroid hormone response, and inflammation. Previous studies revealed that statins, selective inhibitors of the key step of mevalonate pathway, inhibit growth of endometrial stromal cells in vitro and reduce endometriotic lesions in murine models of endometriosis. This study evaluated the effects of simvastatin on the development of endometriosis in a baboon model of this disease. Sixteen baboons were randomly assigned to the treatment group (simvastatin, 20 mg daily) or to the control group. Endometriotic lesions were evaluated by laparoscopy after 3 months. The volume of red, orange-red, and white endometriotic lesions was significantly reduced by 78% in animals treated with simvastatin. The expression of a marker of proliferation, proliferating cell nuclear antigen (PCNA), was significantly reduced in animals receiving simvastatin in red lesions, white lesions, black lesions, and in adhesions. Simvastatin was also associated with an increase in the expression of estrogen receptor alpha in red lesions, and a decrease in the expression of estrogen receptor beta in black lesions, in adhesions, and in eutopic endometrium. Furthermore, simvastatin significantly reduced the expression of neopterin, a marker of inflammation, oxidative stress, and immune system activation. Collectively, the present findings indicate that the inhibition of the mevalonate pathway by simvastatin reduces the risk of developing endometriosis in the primate model of this disease by decreasing the growth of endometrial lesions, by modulating the expression of genes encoding for estrogen receptors, and by reducing inflammation.

Dysfunctional signaling underlying endometriosis: current state of knowledge

Endometriosis is defined as the presence of endometrial tissue outside the uterine cavity. It affects approximately 5-10% of women of reproductive age. Endometriosis is associated with dysmenorrhea, dyspareunia and, often, severe pelvic pain. In addition to pain, women with endometriosis often experience infertility. Defining the molecular etiology of endometriosis is a significant challenge for improving the quality of women's lives. Unfortunately, the pathophysiology of endometriosis is not well understood. Here, we summarize the potential causative factors of endometriosis in the following three categories: (1) dysregulation of immune cells in the peritoneal fluid and endometriotic lesions; (2) alteration of apoptotic signaling in retrograde menstrual tissue and cytotoxic T cells involved in endometriosis progression and (3) dysregulation of oxidative stress. Determining the molecular etiology of these dysregulated cellular signaling pathways should provide crucial clues for understanding initiation and progression of endometriosis. Moreover, improved understanding should suggest new molecular therapeutic targets that could improve the specificity of endometriosis treatments and reduce the side effects associated with current approaches.

Circulating and peritoneal fluid interleukin-6 levels and gene expression in pelvic endometriosis

Current data are inconsistent regarding the association between interleukin-6 (IL-6), a marker of acute phase inflammation, and pelvic endometriosis. The aim of the present study was to assess IL-6 levels in serum and peritoneal fluid (PF), as well as IL-6 gene expression in adipose tissue (AT) and endometrial samples in pelvic endometriosis. A total of 30 patients with endometriosis and 18 women with a normal pelvis were enrolled in this case-control study. IL-6 levels in PF and serum were determined using a human enzyme-linked immunosorbent assay and IL-6 gene expression was evaluated using reverse transcription-quantitative polymerase chain reaction. It was observed that IL-6 levels in the PF were higher in patients with endometriosis than in the control group (P=0.047) and patients with stage III/IV endometriosis exhibited higher IL-6 levels in the PF than those with stage I/II endometriosis and the control group (P<0.001). Furthermore, a strong correlation between PF IL-6 levels and the revised American Society for Reproductive Medicine score for endometriosis severity was identified (r=0.77; P<0.001). IL-6 gene expression did not differ significantly between endometriosis and control groups in endometrial samples or in AT of both groups. The results of the current study suggest that there may be an association between IL-6 and the presence and severity of pelvic endometriosis. The source of this higher IL-6 seems not to be specifically related to regional AT.

Hypoxia-inhibited DUSP2 expression promotes IL-6/STAT3 signaling in endometriosis

PROBLEM

How does hypoxia-mediated downregulation of dual-specificity phosphatase-2 (DUSP2) promote the development of endometriotic lesions?

METHOD OF STUDY

The levels of IL-6 and DUSP2 were assessed in eutopic stromal cells with DUSP2 knockdown or hypoxia treatment. Bromodeoxyuridine (BrdU) incorporation was applied for evaluating cell proliferation. The protein levels of DUSP2, cleaved caspase-3, phosphorylated STAT3, and STAT3 were analyzed using immunoblot.

RESULTS

The genomewide analysis of cells with DUSP2 overexpression indicated IL-6 regulates multiple pathways related to inflammation, proliferation, and apoptosis. DUSP2 overexpression significantly suppressed IL-6 expression, while DUSP2 knockdown promoted IL-6 expression. The hypoxia-treated eutopic stromal cells expressed higher levels of IL-6, recapitulating the elevated levels of IL-6 in ectopic stromal cells. The treatment with IL-6 elicited the phosphorylation of STAT3, mimicking the elevated levels of phosphorylated STAT3 in the ectopic stromal cells. The IL-6-treated eutopic stromal cells showed more BrdU incorporation and less cleaved caspase-3, which can be reversed by STAT3 inhibitor.

CONCLUSION

Hypoxia-induced IL-6 production in endometriotic lesions is mediated via downregulation of DUSP2, which causes aberrant activation of STAT3 signaling pathway and helps the endometriotic cells survive under the ectopic environment.

Clinical management of endometriosis-associated infertility

Endometriosis is a common chronic benign disease that affects reproductive age women and causes chronic pelvic pain and infertility. Despite its prevalence, the exact mechanisms of the pathogenesis of endometriosis-associated infertility are unknown, and precise standards of management have not yet been established. Medical and surgical treatments for endometriosis have different effects on the chance of conception, either spontaneously or via assisted reproductive technologies (ART). In this manuscript, we review the literature from years 1979 to 2015 to report on the proposed mechanism of endometriosis-associated infertility, the staging system of endometriosis for pregnancy outcomes and the current management of patients with endometriosis-associated infertility.

Prospective Evaluation of a Panel of Plasma Cytokines and Chemokines as Potential Markers of Pelvic Endometriosis in Symptomatic Women

BACKGROUND

Endometriosis is a chronic inflammatory disease for which no accurate peripheral diagnostic marker is available. Many cytokines and chemokines have been found altered in the plasma and peritoneal fluid of women with endometriosis compared to healthy controls, but little is known about their diagnostic utility to confirm or discard endometriosis among symptomatic women.

OBJECTIVE

The study aims to assess the diagnostic value of a panel of plasma cytokines and chemokines to detect endometriosis in women undergoing laparoscopy for gynecological complains.

METHODS

We performed a prospective cohort study evaluating simultaneously plasma concentrations of interleukin (IL)-2, IL-4, IL-6, IL-10, MCP-1/CCL2, IP-10/CXCL10 and eotaxin/CCL11 in 75 symptomatic women (chronic pelvic pain, infertility or ovarian cyst) submitted to laparoscopy. Assays were performed by Cytometric Bead Array System. Endometriosis was confirmed by histopathological examination of surgical specimens.

RESULTS

Plasma IL-2, IL-4, IL-6, IL-10, MCP-1/CCL2, IP-10/CXCL10 and eotaxin/CCL11 concentrations were not able to distinguish the women who eventually were diagnosed with endometriosis.

CONCLUSION

Although previously shown to be altered in women with endometriosis compared to healthy women, the tested cytokines and chemokines were not useful to predict the presence of endometriosis among symptomatic women. This finding suggests that inflammatory markers modified by endometriosis may also be altered by other conditions associated with similar symptoms, which limits their use in clinical practice.

Enhanced epithelial to mesenchymal transition (EMT) and upregulated MYC in ectopic lesions contribute independently to endometriosis

BACKGROUND

Epithelial to mesenchymal transition (EMT) is a process in which epithelial cells lose polarity and cell-to-cell contacts and acquire the migratory and invasive abilities of mesenchymal cells. These abilities are thought to be prerequisites for the establishment of endometriotic lesions. A hallmark of EMT is the functional loss of E-cadherin (CDH1) expression in epithelial cells. TWIST1, a transcription factor that represses E-cadherin transcription, is among the EMT inducers. SNAIL, a zinc-finger transcription factor, and its close relative SLUG have similar properties to TWIST1 and are thus also EMT inducers. MYC, which is upregulated by estrogens in the uterus by an estrogen response cis-acting element (ERE) in its promoter, is associated with proliferation in endometriosis. The role of EMT and proliferation in the pathogenesis of endometriosis was evaluated by analyzing TWIST1, CDH1 and MYC expression.

METHODS

CDH1, TWIST1, SNAIL and SLUG mRNA expression was analyzed by qRT-PCR from 47 controls and 74 patients with endometriosis. Approximately 42 ectopic and 62 eutopic endometrial tissues, of which 30 were matched samples, were collected during the same surgical procedure. We evaluated TWIST1 and MYC protein expression by immunohistochemistry (IHC) in the epithelial and stromal tissue of 69 eutopic and 90 ectopic endometrium samples, of which 49 matched samples were analyzed from the same patient. Concordant expression of TWIST1/SNAIL/SLUG and CDH1 but also of TWIST1 and MYC was analyzed.

RESULTS

We found that TWIST1, SNAIL and SLUG are overexpressed (p < 0.001, p = 0.016 and p < 0.001) in endometriosis, while CDH1 expression was concordantly reduced in these samples (p < 0.001). Similar to TWIST1, the epithelial expression of MYC was also significantly enhanced in ectopic endometrium compared to eutopic tissues (p = 0.008). We found exclusive expression of either TWIST1 or MYC in the same samples (p = 0.003).

CONCLUSIONS

Epithelial TWIST1 is overexpressed in endometriosis and may contribute to the formation of endometriotic lesions by inducing epithelial to mesenchymal transition, as CDH1 was reduced in ectopic lesions. We found exclusive expression of either TWIST1 or MYC in the same samples, indicating that EMT and proliferation contribute independently of each other to the formation of endometriotic lesions.

Aberrant activation of signal transducer and activator of transcription-3 (STAT3) signaling in endometriosis

STUDY QUESTION

Are STAT3 signaling molecules differentially expressed in endometriosis?

SUMMARY ANSWER

Levels of phospho-STAT3 and HIF1A, its downstream signaling molecule, are significantly higher in eutopic endometrium from women with endometriosis when compared with women without the disease.

WHAT IS KNOWN ALREADY

Endometriosis is an estrogen-dependent inflammatory condition. Interleukin 6 (IL-6) is an inflammatory survival cytokine known to induce prolonged activation of STAT3 via association with the IL-6 receptor.

STUDY DESIGN, SIZE, DURATION

Cross-sectional measurements of STAT3 and HIF1A protein levels in eutopic endometrium from women with endometriosis versus those without.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Levels of phospho-STAT3 (pSTAT3) and HIF1A were examined in the endometrium of patients with and without endometriosis as well as in a non-human primate animal model using western blot and immunohistochemical analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

Levels of pSTAT3 were significantly higher in the eutopic endometrium from women with endometriosis when compared with women without the disease in both the proliferative and secretory phases. HIF1A is known to be stabilized by STAT3 and IL-6. Our immunohistochemistry results show abundant HIF1A expression within the eutopic endometrial epithelial cells of women with endometriosis. Furthermore, pSTAT3 and HIF1A proteins are co-localized in endometriosis. This aberrant activation of pSTAT3 and HIF1A is confirmed by sequential analysis of eutopic endometrium using a baboon animal model of induced endometriosis. Lastly, we confirmed this IL-6 induction of both STAT3 phosphorylation and HIF1A mRNA expression in Ishikawa human endometrial adenocarcinoma cell line.

LIMITATIONS, REASONS FOR CAUTION

Ishikawa cancer cell line was used to study a benign disease. The peritoneal fluid contains various inflammatory cytokines in addition to IL-6 and so it is possible that other cytokines may affect the activity and expression of STAT3 signaling molecules.

WIDER IMPLICATIONS OF THE FINDINGS

Our results imply that aberrant activation of STAT3 signaling plays an important role in the pathogenesis of endometriosis. Our findings could progress in our understanding of the etiology and pathophysiology of endometriosis and potential therapeutic interventions by targeted pharmacological.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by NIH R01 HD067721 (to S.L.Y and B.A.L) and NIH R01 HD057873 and American Cancer Society Research Grant RSG-12-084-01-TBG (to J.-W.J.). There are no conflicts of interest.

The cellular inhibitor of apoptosis protein-2 is a possible target of novel treatment for endometriosis

PROBLEM

How is the tumor necrosis factor (TNF) α-induced inhibitor of apoptosis (IAP) protein expression in endometriotic stromal cells (ESCs) involved in cell viability and signaling pathways?

METHOD OF STUDY

Endometriotic stromal cells were isolated from ovarian chocolate cysts in 20 patients who underwent laparoscopic surgery. IAP protein expression and IκB phosphorylation were evaluated by Western blot analysis. Interleukin (IL)-8 protein expression and cell proliferation were assessed by ELISA.

RESULTS

Cellular IAP (cIAP)-2 protein expression in endometriotic tissue was higher than that of endometrium. TNFα markedly enhanced cIAP-2 protein expression in ESCs. Pretreatment with a nuclear factor (NF)-κB inhibitor attenuated TNFα-induced cIAP-2 expression. An antagonist of IAPs abrogated TNFα-induced cIAP-2 protein expression and showed a decrease in TNFα-induced IL-8 protein expression and BrdU incorporation in ESCs.

CONCLUSIONS

TNFα and its downstream NFκB pathway have proven to be critical regulators of highly expressed cIAP-2 in ESCs. cIAP-2 may be a novel therapeutic target for endometriosis.

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.

Inducers of G-protein coupled estrogen receptor (GPER) in endometriosis: potential implications for macrophages and follicle maturation

Endometriosis is an estrogen dependent chronic inflammation and thus a condition of stress. Though the G-protein coupled estrogen receptor (GPER) has been shown to be up-regulated in ovarian endometriosis, insights involved in inducing this receptor expression are largely elusive. Therefore, this study investigated whether stress-related factors (ACTH, prednisolone) or inflammatory factors (IL-1β, TNFα, and PGE(2)) factors may affect GPER. To further link GPER to endometriosis pathophysiology it was tracked in macrophages and follicles of endometriotic ovaries. This study found GPER expression to be modulated by stress-related hormones as well as inflammation and to be up-regulated in endometriosis-associated macrophages. At the same time, follicles of ovaries affected by endometriosis presented significantly reduced GPER positivity when compared to controls, suggesting a possible way by which endometriosis may affect folliculogenesis. The multiple roles of GPER as presented herein make it a promising future candidate for targeted molecular endometriosis treatment.

Parthenolide reduces cell proliferation and prostaglandin E2 [corrected] in human endometriotic stromal cells and inhibits development of endometriosis in the murine model

OBJECTIVE

To evaluate the effects of parthenolide on human endometriotic cells and murine endometriotic lesions.

DESIGN

Experimental study.

SETTING

University hospital and laboratory of animal science.

PATIENT(S) AND ANIMAL(S)

Twenty women with ovarian endometrioma and 30 mice.

INTERVENTION(S)

Ectopic endometrial tissue from the endometrioma was collected.

MAIN OUTCOME MEASURE(S)

Human endometriotic stromal cells (ESCs) were pretreated with parthenolide and exposed to tumor necrosis factor (TNF)-α. Interleukin 8 (IL-8) and COX-2 gene expressions were evaluated by real-time reverse transcription-polymerase chain reaction. Interleukin-8 protein, prostaglandin E₂ (PGE₂) level, and intranuclear p65 protein concentration were determined by ELISA. Cell proliferation was assessed by 5-bromo-2'-deoxyuridine-ELISA. Phosphorylation of signaling pathways in ESCs was evaluated by Western blotting. Gene expression and proliferative activity in murine endometriosis-like lesions were assessed by real-time reverse transcription-polymerase chain reaction and Ki67 staining, respectively.

RESULT(S)

With parthenolide pretreatment, TNF-α-induced IL-8 gene and protein expression in ESCs were diminished. Tumor necrosis factor α-induced COX-2 expression and PGE2 synthesis were also inhibited. Adding parthenolide repressed TNF-α-induced 5-bromo-2'-deoxyuridine incorporation and IκB phosphorylation in ESCs. As in vivo experiments, administering parthenolide reduced the number, surface area, and weight, the level of Vegf, Il-6, Mcp-1, and Lif gene expression, and the percentage of Ki67-positive cells in murine endometriosis-like lesions.

CONCLUSION(S)

Parthenolide repressed the development of endometriosis by suppressing the inflammatory peritoneal environment through the nuclear factor κB pathway.

CDC42-positive macrophages may prevent malignant transformation of ovarian endometriosis

It is currently thought that most clear cell and endometrioid carcinomas arise from ovarian endometriosis. We recently suggested that, besides their origin in the ovary, reduction of CDC42 messenger RNA (a member of the RHO GTPase family) may contribute to explain why clear cell carcinomas are not uncommonly found limited to the ovary (stage I). On the other hand, little is known about the expression of CDC42 in ovarian endometriosis with and without carcinoma. Twenty-two endometriotic cysts not associated with carcinoma, 19 endometriotic cysts associated with carcinoma (contiguous endometriosis), as well as the 19 corresponding tumors (11 clear cell, 4 endometrioid, and 4 mixed-clear cell and endometrioid-carcinomas) were investigated. We analyzed CDC42 expression both by real-time polymerase chain reaction and immunohistochemistry. Endometriotic cysts not associated with carcinoma showed higher expression of CDC42 messenger RNA than cysts associated with carcinoma (P = .002). Immunohistochemically, CDC42 was exclusively expressed by macrophages. CDC42-positive macrophages were present in most of the endometriotic cysts not associated with carcinoma (11/19, or 58%). In contrast, only 5 endometriotic cysts containing carcinoma (contiguous endometriosis) (5/18, or 28%) and 1 ovarian carcinoma arising from endometriosis (1/18, or 5%) had CDC42-positive macrophages (58% versus 28%, P = .065; 28% versus 5%, P = .046). Our results raise the possibility that CDC42-positive macrophages may prevent the development of endometrioid and clear cell carcinomas.

Apoptosis resistance in endometriosis

INTRODUCTION

In a cytological analysis of endometriotic lesions neither granulocytes nor cytotoxic T-cells appear in an appreciable number. Based on this observation we aimed to know, whether programmed cell death plays an essential role in the destruction of dystopic endometrium. Disturbances of the physiological mechanisms of apoptosis, a persistence of endometrial tissue could explain the disease. Another aspect of this consideration is the proliferation competence of the dystopic mucous membrane.

METHODS

Endometriotic lesions of 15 patients were examined through a combined measurement of apoptosis activity with the TUNEL technique (terminal deoxyribosyltransferase mediated dUTP Nick End Labeling) and the proliferation activity (with the help of the Ki-67-Antigens using the monoclonal antibody Ki-S5).

RESULTS

Twelve out of 15 women studied showed a positive apoptotic activity of 3-47% with a proliferation activity of 2-25% of epithelial cells. Therefore we concluded that the persistence of dystopic endometrium requires proliferative epithelial cells from middle to lower endometrial layers.

CONCLUSION

A dystopia misalignment of the epithelia of the upper layers of the functionalism can be rapidly eliminated by apoptotic procedures.

Proteolytic tailoring of the heat shock protein 70 and its implications in the pathogenesis of endometriosis

OBJECTIVE

To investigate the mechanism underlying the appearance of a 20-kd HSP70 fragment and its consequences in the ectopic endometrium of endometriosis patients.

DESIGN

Experimental study.

SETTING

Research institute and obstetrics and gynecology clinic.

PATIENT(S)

Participants with (n = 18) and without (n = 20) endometriosis.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Reverse-transcription polymerase chain reaction, protease assays, and in silico tools were used to investigate the origin of the 20-kd HSP70 fragment. Immunocolocalization studies were carried out to determine whether subtilisin/kexin isozyme 1 (SKI-1) and HSP70 are colocalized. Expression and localization of surrogate markers of inflammation, such as nuclear factor NF-κB and interleukin IL-6 were examined by immunoblotting and in situ studies.

RESULT(S)

HSP70 is posttranslationally processed into a 20-kd fragment by SKI-1, a protease of the subtilisin family, in ectopic endometrium (ECE). Immunocolocalization studies revealed spatial proximity of SKI-1 and HSP70 in ECE. Furthermore, ECE demonstrated nuclear localization of the transcription factor, NF-κB and high expression of its target protein, IL-6.

CONCLUSION(S)

This study hints at the possible mechanisms underlying the trimming of HSP70 in ECE and also at the role of proteases in the pathogenesis of endometriosis. The possible repercussions of HSP70 fragmentation include dysregulation of key regulatory proteins, resulting in the escalation of inflammatory events in endometriotic lesions.

Differential expression of microRNAs between eutopic and ectopic endometrium in ovarian endometriosis

Endometriosis, defined as the presence of endometrial tissue outside the uterus, is a common gynecological disease with poorly understood pathogenesis. MicroRNAs are members of a class of small noncoding RNA molecules that have a critical role in posttranscriptional regulation of gene expression by repression of target mRNAs translation. We assessed differentially expressed microRNAs in ectopic endometrium compared with eutopic endometrium in 3 patients through microarray analysis. We identified 50 microRNAs differentially expressed and the differential expression of five microRNAs was validated by real-time RT-PCR in other 13 patients. We identified in silico their predicted targets, several of which match the genes that have been identified to be differentially expressed in ectopic versus eutopic endometrium in studies of gene expression. A functional analysis of the predicted targets indicates that several of these are involved in molecular pathways implicated in endometriosis, thus strengthening the hypothesis of the role of microRNAs in this pathology.

Interleukin-6 and other soluble factors in peritoneal fluid and endometriomas and their relation to pain and aromatase expression

Immunological changes and gene expression anomalies are involved in the etiopathophysiology of endometriosis, although how these alterations are connected is not well established. The aim of this study was to determine the relationship between levels of immune cell populations, cytokines and CA-125 in peritoneal fluid (PF) and 'chocolate' cyst fluid (CF), and aromatase expression in endometriotic tissue, as well as to investigate any association with symptoms or recurrence of the disease. Eutopic and ectopic endometrium, CF and PF were collected from 84 women with endometriomas and 24 with benign non-functioning ovarian tumors undergoing radical or conservative surgery. Immunohistochemistry was performed to determine aromatase expression. PF cell populations were assessed by flow cytometry, and CF and PF levels of interleukin (IL)-6, IL-8, IL-13, IL-17 and CA-125 were quantified by ELISA. These parameters were compared with aromatase expression, symptoms and recurrence of the disease. IL-6 levels in PF were higher in patients with endometriosis than in patients with benign non-functioning ovarian cysts, and correlated positively to dysmenorrhea and pelvic pain in the first group. An association between PF IL-8 and CA-125 was also observed in endometriosis. Aromatase positive patients showed higher levels of PF CA-125 and CF IL-17. Recurrence of symptoms or endometrioma occurred sooner in patients having higher IL-6 or IL-8 levels in CF, respectively. These findings suggest an association of IL-6 with pain in endometriosis, as well as a relationship between cytokine expression and recurrence of the disease. However no clear relationship between aromatase expression and other parameters was found.