Molecular profiling of experimental endometriosis identified gene expression patterns in common with human disease

Cannabidiol as a possible treatment for endometriosis through suppression of inflammation and angiogenesis

BACKGROUND

Endometriosis is associated with a wide variety of signs and symptoms and can lead to infertility, embryo death, and even miscarriage. Although the exact pathogenesis and etiology of endometriosis is still unclear, it has been shown that it has a chronic inflammatory nature and angiogenesis is also involved in it.

OBJECTIVE

This review aims to explore the role of inflammation and angiogenesis in endometriosis and suggest a potential treatment targeting these pathways.

FINDINGS

Among the pro-inflammatory cytokines, studies have shown solid roles for interleukin 1β (IL-β), IL-6, and tumor necrosis factor α (TNF-α) in the pathogenesis of this condition. Other than inflammation, angiogenesis, the formation of new blood vessels from pre-existing capillaries, is also involved in the pathogenesis of endometriosis. Among angiogenic factors, vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1α (HIF-1α), transforming growth factor β1 (TGF-β1), and matrix metalloproteinases (MMPs) are more essential in the pathogenesis of endometriosis. Interestingly, it has been shown that inflammation and angiogenesis share some similar pathways with each other that could be potentially targeted for treatment of diseases caused by these two processes. Cannabidiol (CBD) is a non-psychoactive member of cannabinoids which has well-known and notable anti-inflammatory and antiangiogenic properties. This agent has been shown to decrease IL-1β, IL-6, TNF-α, VEGF, TGFβ, and MMPs in different animal models of diseases.

CONCLUSION

It seems that CBD could be a possible treatment for endometriosis due to its anti-inflammatory and antiangiogenic activity, however, further studies are needed.

A Comprehensive Review of the Efficacy and Safety of Dopamine Agonists for Women with Endometriosis-associated Infertility from Inception to July 31, 2022

Background

Current medical management of endometriosis leads to suppression of ovulation and will not be helpful for women with endometriosis who are desirous of pregnancy. Thus, drugs that can both treat endometriosis and its associated infertility are highly warranted.

Objective

Anti-angiogenic agents are potential drugs for patients with endometriosis and infertility. Among these drugs, dopamine agonist (DA) is promising since it does not interfere with ovulation, is safe, and not teratogenic. The aim of the study is to determine the efficacy and safety of DA for improving reproductive outcomes in women with endometriosis and infertility.

Methods

A qualitative narrative review was done from inception to July 31, 2022 using the appropriate MeSH terms in PubMed, Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, ClinicalTrial.gov, and World Health Organization International Clinical Trials Registry Platform. Date analysis was through qualitative analysis and synthesis of researches and their outcome measures.

Results

No studies used the core outcomes for trials evaluating treatments for infertility associated with endometriosis. All the included articles in the review supported the possible anti-angiogenic effects of DA on the vascular endothelial growth factor [VEGF] /VEGF receptor system. The use of DA does not have an effect on ovulation and menstrual cyclicity. Studies on safety profile of DA were consistent with existing data.

Conclusion

Most of studies reviewed demonstrated that DA were effective in reducing endometriotic lesions. However, further research is required to establish whether this anti-angiogenic effect can improve reproductive outcomes in women with endometriosis-associated infertility.

Dissecting the shared genetic architecture between endometriosis and polycystic ovary syndrome

Background

Previous study suggested evidence for coexistence and similarities between endometriosis and polycystic ovary syndrome (PCOS), but it is unclear regarding the shared genetic architecture and causality underlying the phenotypic similarities observed for endometriosis and PCOS.

Methods

By leveraging summary statistics from public genome-wide association studies regarding endometriosis (European-based: N=470,866) and PCOS (European-based: N=210,870), we explored the genetic correlation that shared between endometriosis and PCOS using linkage disequilibrium score regression. Shared risk SNPs were derived using PLACO (Pleiotropic analysis under composite null hypothesis) and FUMA (Functional Mapping and Annotation of Genetic Associations). The potential causal association between endometriosis and PCOS was investigated using two-sample Mendelian randomization (MR). Linkage disequilibrium score for the specific expression of genes analysis (LDSC-SEG) were performed for tissue enrichment analysis. The expression profiles of the risk gene in tissues were further examined.

Results

A positive genetic association was observed between endometriosis and PCOS. 12 significant pleiotropic loci shared between endometriosis and PCOS were identified. Genetic associations between endometriosis and PCOS were particularly enriched in uterus, endometrium and fallopian tube. Two-sample MR analysis further indicated a potential causative effect of endometriosis on PCOS, and vice versa. Microarray and RNA-seq verified the expressions of SYNE1 and DNM3 were significantly altered in the endometrium of patients with endometriosis or PCOS compared to those of control subjects.

Conclusion

Our study indicates the genetic correlation and shared risk genes between PCOS and endometriosis. These findings provide insights into the potential mechanisms behind their comorbidity and the future development of therapeutics.

Uterine Collagen Cross-Linking: Biology, Role in Disorders, and Therapeutic Implications

Collagen is an essential constituent of the uterine extracellular matrix that provides biomechanical strength, resilience, structural integrity, and the tensile properties necessary for the normal functioning of the uterus. Cross-linking is a fundamental step in collagen biosynthesis and is critical for its normal biophysical properties. This step occurs enzymatically via lysyl oxidase (LOX) or non-enzymatically with the production of advanced glycation end-products (AGEs). Cross-links found in uterine tissue include the reducible dehydro-dihydroxylysinonorleucine (deH-DHLNL), dehydro-hydroxylysinonorleucine (deH-HLNL), and histidinohydroxymerodesmosine (HHMD); and the non-reducible pyridinoline (PYD), deoxy-pyridinoline (DPD); and a trace of pentosidine (PEN). Collagen cross-links are instrumental for uterine tissue integrity and the continuation of a healthy pregnancy. Decreased cervical cross-link density is observed in preterm birth, whereas increased tissue stiffness caused by increased cross-link density is a pathogenic feature of uterine fibroids. AGEs disrupt embryo development, decidualization, implantation, and trophoblast invasion. Uterine collagen cross-linking regulators include steroid hormones, such as progesterone and estrogen, prostaglandins, proteoglycans, metalloproteinases, lysyl oxidases, nitric oxide, nicotine, and vitamin D. Thus, uterine collagen cross-linking presents an opportunity to design therapeutic targets and warrants further investigation in common uterine disorders, such as uterine fibroids, cervical insufficiency, preterm birth, dystocia, endometriosis, and adenomyosis.

Chronic Pelvic Puzzle: Navigating Deep Endometriosis with Renal Complications

This case report delves into the intricacies of a challenging clinical scenario involving deep pelvic endometriosis, which manifested with renal complications. Endometriosis, a complex gynecological condition, is explored in this case, highlighting its multifaceted nature. The patient presented with a complex interplay of symptoms, including chronic pelvic pain, urinary tract issues, and severe deep adenomyosis. The diagnostic journey was protracted, emphasizing the need for early recognition and intervention in such cases. A thorough evaluation, including laparoscopic examination and histopathological analysis, revealed the extensive presence of endometriotic lesions in various pelvic and renal structures, ultimately leading to left hydronephrosis. The report underscores the significance of timely diagnosis and surgical intervention to prevent irreversible renal damage. This case provides valuable insights into the management of deep endometriosis with renal involvement and the importance of interdisciplinary collaboration. Understanding the complexities of this condition can aid in improving patient outcomes and enhancing the quality of care provided.

MLLT11 Regulates Endometrial Stroma Cell Adhesion, Proliferation and Survival in Ectopic Lesions of Women with Advanced Endometriosis

MLLT11 is a gene implicated in cell differentiation and the development and progression of human cancers, but whose role in the pathogenesis of endometriosis is still unknown. Using quantitative RT-PCR and immunohistochemistry, we analyzed 37 women with and 33 women without endometriosis for differences in MLLT11 expression. We found that MLLT11 is reduced in the ectopic stroma cells of women with advanced stage endometriosis compared to women without endometriosis. MLLT11 knockdown in control stroma cells resulted in the downregulation of their proliferation accompanied by G1 cell arrest and an increase in the expression of p21 and p27. Furthermore, the knockdown of MLLT11 was associated with increased apoptosis resistance to camptothecin associated with changes in BCL2/BAX signaling. Finally, MLLT11 siRNA knockdown in the control primary stroma cells led to an increase in cell adhesion associated with the transcriptional activation of ACTA2 and TGFB2. We found that the cellular phenotype of MLLT11 knockdown cells resembled the phenotype of the primary endometriosis stroma cells of the lesion, where the levels of MLLT11 are significantly reduced compared to the eutopic stroma cells of women without the disease. Overall, our results indicate that MLLT11 may be a new clinically relevant player in the pathogenesis of endometriosis.

Copper in Gynecological Diseases

Copper (Cu) is an essential micronutrient for the correct development of eukaryotic organisms. This metal plays a key role in many cellular and physiological activities, including enzymatic activity, oxygen transport, and cell signaling. Although the redox activity of Cu is crucial for enzymatic reactions, this property also makes it potentially toxic when found at high levels. Due to this dual action of Cu, highly regulated mechanisms are necessary to prevent both the deficiency and the accumulation of this metal since its dyshomeostasis may favor the development of multiple diseases, such as Menkes' and Wilson's diseases, neurodegenerative diseases, diabetes mellitus, and cancer. As the relationship between Cu and cancer has been the most studied, we analyze how this metal can affect three fundamental processes for tumor progression: cell proliferation, angiogenesis, and metastasis. Gynecological diseases are characterized by high prevalence, morbidity, and mortality, depending on the case, and mainly include benign and malignant tumors. The cellular processes that promote their progression are affected by Cu, and the mechanisms that occur may be similar. We analyze the crosstalk between Cu deregulation and gynecological diseases, focusing on therapeutic strategies derived from this metal.

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

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

Ginsenosides in endometrium-related diseases: Emerging roles and mechanisms

Ginsenosides, agents extracted from an important herb (ginseng), are expected to provide new therapies for endometrium-related diseases. Based on the molecular types of ginsenosides, we reviewed the main pharmacological effects of ginsenosides against endometrium-related diseases (e.g., endometrial cancers, endometriosis, and endometritis). The mechanism of action of ginsenosides involves inducing apoptosis of endometrium-related cells, promoting autophagy of endometrium-related cells, regulating epithelial-mesenchymal transition (EMT) in endometrium-related cells, and activating the immune system to kill cells associated with endometrial diseases. We hope to provide a theoretical foundation for the treatment of endometrium-related diseases by ginsenosides.

The copper chelator ammonium tetrathiomolybdate inhibits the progression of experimental endometriosis in TNFR1-deficient mice

The TNF-α/TNFR system is involved in endometriosis (EDT), a gynecologic estrogen-dependent disease. Elevated copper concentrations have also been associated with EDT, even in TNFR1-deficient mice where disease worsening occurs. We aimed to evaluate whether treatment with ammonium tetrathiomolybdate (TM, copper chelator) is beneficial in TNFR1-deficient mice presenting with worsened EDT status. Female C57BL/6 mice were divided into three groups: KO Sham, KO EDT, and KO EDT+TM. TM was administered from the 15th postoperative day, and samples were collected one month after inducing pathology. In peritoneal fluid, copper and estradiol levels were determined by electrothermal atomic absorption spectrometry and electrochemiluminescence, respectively. Lesions were processed for the analysis of cell proliferation (PCNA immunohistochemistry), expression of angiogenic markers (RT-qPCR), and oxidative stress (spectrophotometric methods). We found that EDT increased copper and estradiol levels compared to the KO Sham group, while the TM administration restored the levels of both factors. TM also reduced the volume and weight of the lesions and cell proliferation rate. Besides, TM treatment decreased the number of blood vessels and the Vegfa, Fgf2, and Pdgfb expression. Furthermore, superoxide dismutase and catalase activity decreased, and lipid peroxidation increased. TM administration inhibits EDT progression in TNFR1-deficient mice where the pathology is exacerbated.

Assessment of BMP7, SMAD4, and CDH1 Expression Profile and Regulatory miRNA-542-3p in Eutopic and Ectopic Endometrium of Women with Endometriosis

Alterations in the expression of numerous genes and the miRNAs that are recognized as their regulators in the endometrial cells of women with endometriosis may disrupt the intracellular signaling pathways associated with epithelial–mesenchymal transition (EMT). So far, the functional role of BMP7 in endometrial physiology has been confirmed, especially in the context of fertility, but the role of the activation of a specific mechanism operating through the BMP–SMAD–CDH1 axis in the formation of endometrial lesions remains unexplored. The aim of this study was to evaluate the expression profile of miR-542-3p and the EMT markers (BMP7, SMAD4, CDH1) in matched eutopic endometrium (EUE) and ectopic endometrium (ECE) samples from women with endometriosis in relation to healthy women. The levels of expression of the studied genes and miRNA in peripheral blood mononuclear cells (PBMCs) obtained from women diagnosed with endometriosis and those without the disease were also evaluated. Fifty-four patients (n = 54: with endometriosis—n = 29 and without endometriosis—n = 25) were included in the study. A comparative analysis of the relative mean expression values (RQ) of the studied mRNA and miRNA assessed by RT-qPCR demonstrated downregulation of BMP7, SMAD4, and CDH1 expression in ectopic lesions and upregulation in the eutopic endometrium compared with the control group. In the eutopic tissue of women with endometriosis, miR-542-3p expression was similar to that of the control but significantly lower than in endometrial lesions. We also confirmed a trend towards a negative correlation between miR-542-3p and BMP7 in ectopic tissue, and in PBMC, a significant negative correlation of miR-542-3p with further BMP signaling genes, i.e., SMAD4 and CDH1, was observed. These results indicate that the miRNA selected by us may be a potential negative regulator of BMP7-SMAD4-CDH1 signaling associated with EMT. The different patterns of BMP7, SMAD4, and CDH1 gene expression in ECE, EUE, and the control endometrium observed by us suggests the loss of the endometrial epithelium phenotype in women with endometriosis and demonstrates their involvement in the pathogenesis and pathomechanism of this disease.

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.

Diagnostic gene biomarkers for predicting immune infiltration in endometriosis

OBJECTIVE

To determine the potential diagnostic markers and extent of immune cell infiltration in endometriosis (EMS).

METHODS

Two published profiles (GSE7305 and GSE25628 datasets) were downloaded, and the candidate biomarkers were identified by support vector machine recursive feature elimination analysis and a Lasso regression model. The diagnostic value and expression levels of biomarkers in EMS were verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blotting, then further validated in the GSE5108 dataset. CIBERSORT was used to estimate the composition pattern of immune cell components in EMS.

RESULTS

One hundred and fifty-three differential expression genes (DEGs) were identified between EMS and endometrial with 83 upregulated and 51 downregulated genes. Gene sets related to arachidonic acid metabolism, cytokine-cytokine receptor interactions, complement and coagulation cascades, chemokine signaling pathways, and systemic lupus erythematosus were differentially activated in EMS compared with endometrial samples. Aquaporin 1 (AQP1) and ZW10 binding protein (ZWINT) were identified as diagnostic markers of EMS, which were verified using qRT-PCR and western blotting and validated in the GSE5108 dataset. Immune cell infiltrate analysis showed that AQP1 and ZWINT were correlated with M2 macrophages, NK cells, activated dendritic cells, T follicular helper cells, regulatory T cells, memory B cells, activated mast cells, and plasma cells.

CONCLUSION

AQP1 and ZWINT could be regarded as diagnostic markers of EMS and may provide a new direction for the study of EMS pathogenesis in the future.

Metabolite profiles in the peritoneal cavity of endometriosis patients and mouse models

RESEARCH QUESTION

Which metabolites are altered in the peritoneal cavity of women with endometriosis? Could the mouse endometriosis model simulate these alterations?

DESIGN

Thirteen women with endometriosis and seven women with other benign gynaecological diseases, who underwent laparoscopic surgery, were included in this study. None had received hormonal therapy for 3 months before surgery. For the animal experiments, six and five mice were included in the endometriosis and control groups, respectively. Peritoneal fluid from the patients and peritoneal lavage fluid from the mice was collected and analysed. Non-targeted metabolomics via liquid chromatography with tandem mass spectrometry was used to identify the altered metabolites in the peritoneal fluid of endometriosis patients and mouse models. MetaboAnalyst 4.0 was used to visualize the data.

RESULTS

Several metabolites in the peritoneal cavity were significantly altered in both humans and mice with endometriosis. Concentrations of lysophosphatidylcholine (LysopC) (P=0.017 in patients and P=0.041 in the mouse model) and derivatives of phosphoethanolamine (1-arachidonoyl-sn-glycero-3-phosphoethanolamine in patients, P=0.027; 1-oleoyl-sn-glycero-3-phosphoethanolamine in patients, P=0.0086; and phosphorylethanolamine in the mouse model, P=0.0027) were significantly up-regulated in both, whereas concentrations of acylcarnitines (l-palmitoylcarnitine, P=0.047; and stearoylcarnitine, P=0.029) and kynurenine (P=0.045) were significantly increased only in humans. The human and mouse samples shared three altered enriched metabolite sets.

CONCLUSIONS

Women with endometriosis show an altered metabolic state in the abdominal cavity. The endometriosis mouse model shared half of the significantly altered metabolite sets found in the abdominal cavity of humans.

Diagnostic potential of differentially regulated microRNAs among endometriosis, endometrioid ovarian cancer, and endometrial cancer

Background

There is an increased risk of developing endometrioid ovarian and endometrial cancer in patients with endometriosis and there are no definitive diagnostic biomarkers available for these three associated diseases. Therefore, we evaluated the diagnostic potential of differentially expressed microRNAs (miRNAs) from the tissue samples of endometriosis, endometrioid ovarian cancer, and endometrial cancer to establish them as biomarkers for these diseases.

Materials and Methods

Ten samples of each, i.e., endometriosis, endometrioid ovarian cancer, endometrial cancer and control healthy endometrium were enrolled after obtaining ethical clearance. Differential expression of miR-16, miR-20a, miR-99b, miR-125a, miR-143, and miR-145 and some of their target genes, i.e., vascular endothelial growth factor (VEGF), hypoxia inducible factor 1A (HIF1A), cyclooxygenase 2 (COX2), and tumor necrosis factor (TNF) were quantified using quantitative reverse transcription polymerase chain reaction. Receiver operating characteristic (ROC) curve analysis was performed to predict the diagnostic potential.

Results

miR-16 and miR-20a were significantly downregulated, whereas miR-99b, miR-125a, and miR-143 were significantly upregulated in all three diseased samples. miR-145 was significantly upregulated in endometriosis and endometrioid ovarian cancer but significantly downregulated in endometrial cancer. mRNA levels of VEGF, HIF1A, COX2, and TNF were significantly increased in all three diseased samples as compared to control samples. ROC curve analysis revealed that for endometriosis, miR-99b, and miR-125a were giving highest area under curve (AUC) (0.950 and 0.733, respectively), for endometrioid carcinoma of ovary miR-143 was giving highest AUC (0.933) and for endometrioid endometrial cancer miR-16 (AUC = 0.815), miR-99b (AUC = 0.920), and miR-145 (AUC = 0.985) were found to be best predictors.

Conclusion

These findings suggest that these miRNAs can act as good predictors and discriminators of these three diseases and might serve as potential biomarkers for them.

Investigation on factors related to uterine fibroids in rural women of northern Anhui province

AIM

Given the increasing prevalence of hysteromyoma among the Chinese rural women of childbearing age, it is imperative that more attention should be given to researching risk factors that predispose women to this condition so that early preventive measures may be taken. Our study investigates potential risk factors for uterine fibroids such as participants' demographic characteristics (age, ethnicity, education), physiological characteristics (age at menarche, primiparous age), and the occurrence of several different female reproductive diseases (vaginitis, pelvic inflammatory disease).

METHODS

2200 rural women of reproductive age were screened from a cross-sectional study carried out in the northern Anhui province. Data were collected by questionnaire surveys, gynecological and laboratory examinations and were subjected to univariate and multivariate analysis to evaluate the risk factors for uterine fibroids.

RESULTS

Of the 2200 women, 440 had uterine fibroids. In general, women with endometriosis, ovarian cysts and early menarche were more likely to suffer from hysteromyoma. Factors including higher parity, late age of first childbirth, and a regular menstrual cycle were associated with the reduced risk of uterine fibroids.

CONCLUSIONS

Our findings indicate that parameters such as earlier age of menarche, early primiparous age, lower parity and a variety of female reproductive diseases were associated with an increased risk of uterine fibroids. These findings may be used to guide the formulation of effective prevention and intervention protocols to improve the reproductive health of rural women.

Establishment of endometriotic models: the past and future

Endometriosis is a prevalent chronic disease that affects approximately 6% to 10% of reproductive-aged women. Although numerous researchers have endeavored to explore the etiology of endometriosis over a century, its etiology still remains an enigma. The exploration of pathophysiologic mechanism and novel therapy for endometriosis depends on ideal endometriotic models. In the previous decade, various endometriotic models have been established; therefore, we made a conclusion for available information on these models. This review summarized the common experimental models used in endometriotic studies, including their origins, characteristics, applications, and limitations. Endometriotic models played an important role in studying etiologies and novel treatments of endometriosis during the last decades. Among them, animal models and endometriotic cell lines were viewed as most common studying tools to explore the intrinsic entities of endometriosis. In addition, endometrial organoid also emerged and was regarded as an ideal studying tool for endometriosis research. Different research models collectively complement each other to advance the endometriosis research. The successful establishment of endometrial organoids means that organoids are expected to become an ideal model for studying endometriosis in the future.

Down-regulation of Exosomal miR-214-3p Targeting CCN2 Contributes to Endometriosis Fibrosis and the Role of Exosomes in the Horizontal Transfer of miR-214-3p

Endometriosis (EMs) is defined as the presence of tissue which somewhat resembles endometrial glands and stroma outside the uterus, and elicits fibrosis. Fibrosis is the main factor resulting in pain and infertility, while the aetiology of endometrial fibrosis is unknown. There is strong evidence from numerous experiments showing that connective tissue growth factor (CCN2) plays a central role in fibrogenesis. Exosomal miR-214-3p can regulate the expression of CCN2 through binding to complementary sites in the 3' untranslated region. This study aimed to explore the role of exosomal miR-214-3p in endometriosis fibrosis and the relationship between CCN2 and miR-214-3p in endometriosis fibrosis. Our results demonstrated that miR-214-3p was significantly down-regulated and CCN2 was up-regulated in EMs ectopic lesion and stromal cells compared with EMs eutopic and endometrium of patients without endometriosis. Exosomal miR-214-3p can inhibit fibrosis in EMs through targeting CCN2. The results were explored and verified in vitro and in vivo, respectively. Cell co-culture was used to explore the contributions of exosomes to intercellular information transmission of miR-214-3p. The results showed that exosomes play a pivotal role in the transportation of miR-214-3p between cells. Furthermore, level of exosomal miR-214-3p in endometriosis patients' serum was lower than that in patients without endometriosis. In conclusion, exosomal miR-214-3p can inhibit fibrosis in EMs by targeting CCN2. MiR-214-3p may be considered as a bio-marker and has a potential therapeutic effect in EMs.

Toxic Animal-Based Medicinal Materials Can Be Effective in Treating Endometriosis: A Scoping Review

Animal toxins and venoms have recently been developed as cancer treatments possessing tumor cell growth-inhibitory, antiangiogenesis, and proapoptotic effects. Endometriosis is a common benign gynecological disorder in reproductive-age women, and no definite treatment for this disorder is without severe side effects. As endometriosis and malignant tumors share similar characteristics (progressive, invasive, estrogen-dependent growth, and recurrence), animal toxins and venoms are thought to be effective against endometriosis. The objective of this study was to outline studies using toxic animal-based medicinal materials (TMM) as endometriosis treatment and to explore its clinical applicability. Preclinical and clinical studies using TMM were searched for in four databases from inception to October 2020. A total of 20 studies of TMM on endometriosis were included. In eight clinical studies, herbal medicines containing TMM were effective in relieving symptoms of endometriosis, with no side effects. In twelve experimental studies, the main therapeutic mechanisms of TMM against endometriosis were proapoptotic, antiangiogenesis, estrogen level-reducing, and possible anti-inflammatory effects. TMM are thus considered promising sources for the development of an effective treatment method for endometriosis. Further studies are needed to clarify the therapeutic mechanism of TMM against endometriosis and to provide sufficient grounds for clinical application.

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.

Bioinformatic analysis reveals the importance of epithelial-mesenchymal transition in the development of endometriosis

Background: Endometriosis is a frequently occurring disease in women, which seriously affects their quality of life. However, its etiology and pathogenesis are still unclear. Methods: To identify key genes/pathways involved in the pathogenesis of endometriosis, we recruited 3 raw microarray datasets (GSE11691, GSE7305, and GSE12768) from Gene Expression Omnibus database (GEO), which contain endometriosis tissues and normal endometrial tissues. We then performed in-depth bioinformatic analysis to determine differentially expressed genes (DEGs), followed by gene ontology (GO), Hallmark pathway enrichment and protein-protein interaction (PPI) network analysis. The findings were further validated by immunohistochemistry (IHC) staining in endometrial tissues from endometriosis or control patients. Results: We identified 186 DEGs, of which 118 were up-regulated and 68 were down-regulated. The most enriched DEGs in GO functional analysis were mainly associated with cell adhesion, inflammatory response, and extracellular exosome. We found that epithelial-mesenchymal transition (EMT) ranked first in the Hallmark pathway enrichment. EMT may potentially be induced by inflammatory cytokines such as CXCL12. IHC confirmed the down-regulation of E-cadherin (CDH1) and up-regulation of CXCL12 in endometriosis tissues. Conclusions: Utilizing bioinformatics and patient samples, we provide evidence of EMT in endometriosis. Elucidating the role of EMT will improve the understanding of the molecular mechanisms involved in the development of endometriosis.

Genome-wide profiling of miRNA expression patterns in tubal endometriosis

MicroRNA (miRNA) expression profiles in tubal endometriosis (EM) are still poorly understood. In this study, we analyzed the differential expression of miRNAs and the related gene networks and signaling pathways in tubal EM. Four tubal epithelium samples from tubal EM patients and five normal tubal epithelium samples from uterine leiomyoma patients were collected for miRNA microarray. Bioinformatics analyses, including Ingenuity Pathway Analysis (IPA), Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, were performed. Quantitative real-time polymerase chain reaction (qRT-PCR) validation of five miRNAs was performed in six tubal epithelium samples from tubal EM and six from control. A total of 17 significantly differentially expressed miRNAs and 4343 potential miRNA-target genes involved in tubal EM were identified (fold change >1.5 and FDR-adjusted P value <0.05). IPA indicated connections between miRNAs, target genes and other gynecological diseases like endometrial carcinoma. GO and KEGG analysis revealed that most of the identified genes were involved in the mTOR signaling pathway, SNARE interactions in vesicular transport and endocytosis. We constructed an miRNA-gene-disease network using target gene prediction. Functional analysis showed that the mTOR pathway was connected closely to tubal EM. Our results demonstrate for the first time the differentially expressed miRNAs and the related signal pathways involved in the pathogenesis of tubal EM which contribute to elucidating the pathogenic mechanism of tubal EM-related infertility.

The Pathogenesis of Endometriosis: Molecular and Cell Biology Insights

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

Pharmacological blockage of the CXCR4-CXCL12 axis in endometriosis leads to contrasting effects in proliferation, migration, and invasion

High levels of inflammatory factors including chemokines have been reported in peritoneal fluid and blood of women with endometriosis. CXCL12 mediates its action by interaction with its specific receptor, CXCR4, reported to be elevated in human endometriosis lesions and in the rat model of endometriosis. Activation of the CXCR4-CXCL12 axis increases cell proliferation, migration, and invasion of cancer cells. To obtain insights into the CXCR4 expression profile in lesions and endometrium, as well as functionality of the CXCR4-CXCL12 axis in endometriosis, we analyzed the expression of CXCR4 in tissues on a human tissue array and studied CXCL12-mediated activation of proliferation, invasion, and migration in vitro. We observed differences in levels of nuclear CXCR4 expression among lesion types, being higher in ovarian lesions. Endometriotic cell lines (12Z) showed higher levels of CXCR4, proliferative and migratory potential, and AKT phosphorylation/kinase activity compared to untreated control cells (endometrial epithelial cells). CXCL12 and endometriotic stromal cell-enriched media increased proliferation of non-endometriotic epithelial cells. CXCL12 caused a significant increase in 12Z cell invasion but had no effect on migration; AMD3100, a CXCR4-specific inhibitor, significantly increased invasion of 12Z cells but decreased their migration. However, treatment with CXCL12 plus AMD3100 significantly decreased invasion and migration of 12Z cells. In conclusion, the CXCR4-CXCL12 axis is functional in endometriosis cells, but the expression of CXCR4 varies among lesions. CXCL12 promoted proliferation, migration, and invasion of endometriotic cells, while inducing AKT phosphorylation and activity, but pharmacologically blocking this axis in the absence of the ligand induced their invasiveness.

The nervous system and genomics in endometriosis

Endometriosis is a gynaecological disease that occurs in approximately 10% to 15% of women of reproductive age and up to 47% of infertile women. The presence of implants of endometrial-like glands and stroma outside the uterus, characteristic of this disease, induce a wide variety of symptoms, mainly pelvic pain and infertility. Women suffering from this condition experience great distress, which significantly affects their quality of life. Numerous studies attempting to decipher the pathogenic mechanisms of endometriosis have been conducted around the world, yet its aetiology still remains unknown. It is widely believed that in women with endometriosis, the endometrium has characteristic features that allow the formation of implants once fragments have entered the peritoneal cavity through retrograde menstruation. Furthermore, a strong genetic tendency to develop the disease has been reported among patients and first-degree relatives. Thanks to the recent technological advances achieved in genomics and bioinformatics, a number of studies have had the potential to analyse several aspects of the pathogenesis of endometriosis from a genetic perspective. Due to the recent identification of nerve fibres in the endometrium of women with endometriosis, research on the neurogenesis of the disease has increased in the past few years. However, the genetic aspects of nerve growth in endometriosis have not been analysed in depth and further research providing important insights into the mechanisms that mediate pain in affected patients has the potential to contribute substantially to the future management of the condition.

Anti-angiogenic treatment of endometriosis via anti-VEGFA siRNA delivery by means of peptide-based carrier in a rat subcutaneous model

Development of gene therapy for endometriosis requires inhibition of vascularization in endometrial lesions. We have previously developed CXCR4 receptor-targeted siRNA carrier L1 and observed efficient RNAi-mediated down-regulation of VEGFA gene expression in endothelial cells followed by decrease in VEGFA protein production and inhibition of cell migration. In this study we evaluated L1 carrier as non-viral vector for anti-VEGFA siRNA delivery into endometrial implants in rat subcutaneous endometriosis model created by subcutaneous auto-transplantation of uterus horn's fragments. Therapeutic anti-angiogenic efficiency of anti-VEGFA siRNA/L1 polyplexes was evaluated by lesion size measurement, histopathologic examination, immunohistochemical staining and real-time reverse transcriptase-PCR analysis. After in vivo administration of anti-VEGFA siRNA we observed a 55-60% inhibition of endometriotic lesions growth and approximately two-fold decrease in VEGFA gene expression in comparison with untreated implants. Results of immunohistochemical examination of endometriotic lesions confirmed anti-angiogenic effects of anti-VEGFA siRNA/L1 polyplexes. Ultimately, our results demonstrate the efficiency of anti-angiogenic treatment of EM by means of anti-VEGFA siRNA delivery with L1 peptide-based carrier.

Genome-Wide Analysis on the Landscape of Transcriptomes and Their Relationship With DNA Methylomes in the Hypothalamus Reveals Genes Related to Sexual Precocity in Jining Gray Goats

The Jining Gray goat is famous for its sexual precocity; however, the exact regulatory mechanism is still unknown. The hypothalamus is the key centrum in the process of animal reproduction, especially in signal transduction, and the initiation of puberty. The identification of potential genes and pathways in the hypothalamus of Jining Gray goat is critical to understanding the regulatory mechanism of sexual precocity in these goats. In this study, mRNA transcriptome analysis of the hypothalamus of juvenile and pubertal goats revealed eight genes (NTS, ADORA1, CRH, UCN3, E2F2, PDGFRB, GNRH1, and CACNA1C) and three pathways [neuroactive ligand-receptor interaction; gonadotropin-releasing hormone (GnRH) signal; melanoma] that are involved in this regulation. Subsequent methylation analysis on differentially methylated region (DMR) genes revealed the potential regulation network that influences pubertal onset. Correlation analysis verified the methylation level of some DMR genes correlates negatively with expression level. Integrated analysis between transcriptomes and methylomes identified 80 candidate genes involved in GnRH and neuroactive ligand signal pathways, of which CACNA1C and CRH were differentially expressed genes (DEGs) influenced by methylation level. The GnRH gene was the only DEG not affected by its methylation level. In summary, in this study, we identified eight genes and three pathways that are related to pubertal onset in Jining Gray goats, and the expression of CACNA1C and CRH genes of the GnRH and neuroactive ligand signal pathways were influenced by DNA methylation, while that of the GnRH gene was not affected.

IL-1β Inhibits Connexin 43 and Disrupts Decidualization of Human Endometrial Stromal Cells Through ERK1/2 and p38 MAP Kinase

Inflammation can interfere with endometrial receptivity. We examined how interleukin 1β (IL-1β) affects expression of the uterine gap junction protein connexin 43 (Cx43), which is known to be critical for embryonic implantation. We used an in vitro model of human endometrial stromal cells (ESCs), Western blotting, and a combination of validated, selective kinase inhibitors to evaluate five canonical IL-1β signaling pathways. Cx43 and two other markers of ESC differentiation (prolactin and VEGF) were inhibited predominantly via IL-1β-activated ERK1/2 and p38 MAP kinase cascades. The findings were corroborated using small interfering RNA to silence critical genes in either pathway. By contrast, upregulation of endogenous pro-IL-1α and pro-IL-1β following recombinant IL-1β treatment was mediated via the Jun N-terminal kinase pathway. The clinicopharmacological significance of our findings is that multiple signaling cascades may need to be neutralized to reverse deleterious effects of IL-1β on human endometrial function.

Relevant human tissue resources and laboratory models for use in endometriosis research

Endometriosis is characterized by the growth of endometrium‐like tissue outside the uterus, most commonly on the pelvic peritoneum and ovaries. Although it may be asymptomatic in some women, in others it can cause debilitating pain, infertility or other symptoms including fatigue. Current research is directed both at understanding the complex etiology and pathophysiology of the disorder and at the development of new nonsurgical approaches to therapy that lack the unwanted side effects of current medical management. Tools for endometriosis research fall into two broad categories; patient‐derived tissues, and fluids (and cells isolated from these sources) or models based on the use of cells or animals. In this review, we discuss the literature that has reported data from the use of these tools in endometriosis research and we highlight the strengths and weaknesses of each. Although many different models are reported in the literature, hypothesis‐driven research will only be facilitated with careful experimental design and selection of the most appropriate human tissue from patients with and without endometriosis and combinations of physiologically relevant in vitro and in vivo laboratory models.

Evaluation of two endometriosis models by transplantation of human endometrial tissue fragments and human endometrial mesenchymal cells

BACKGROUND

The animal models of endometriosis could be a valuable alternative tool for clarifying the etiology of endometriosis.

OBJECTIVE

In this study two endometriosis models at the morphological and molecular levels was evaluated and compared.

MATERIALS AND METHODS

The human endometrial tissues were cut into small fragments then they were randomly considered for transplantation into γ irradiated mice as model A; or they were isolated and cultured up to fourth passages. 2×106 cultured stromal cells were transplanted into γ irradiated mice subcutaneously as model B. twenty days later the ectopic tissues in both models were studied morphologically by Periodic acid-Schiff and hematoxylin and eosin staining. The expression of osteopontin (OPN) and matrix metalloproteinase 2 (MMP2) genes were also assessed using real time RT-PCR. 17-β estradiol levels of mice sera were compared before and after transplantation.

RESULTS

The endometrial like glands and stromal cells were formed in the implanted subcutaneous tissue of both endometriosis models. The gland sections per cubic millimeter, the expression of OPN and MMP2 genes and the level of 17-β estradiol were higher in model B than model A (p=0.03).

CONCLUSION

Our observation demonstrated that endometrial mesenchymal stromal cells showed more efficiency to establish endometriosis model than human endometrial tissue fragments.

Bone Marrow Stem Cell Chemotactic Activity Is Induced by Elevated CXCl12 in Endometriosis

Endometriosis is an inflammatory gynecological disorder caused by the growth of endometrial tissue outside the uterus. Endometriosis produces chemokines, including CXCL12, that attract bone marrow cells to the lesions. In this study, we describe the expression, localization, and chemotactic activity of CXCL12 in endometriotic lesions. Biopsies were collected both from women with endometriosis undergoing laparoscopy and control endometrium from women without endometriosis. Expression of CXCl12 and CXCR4 messenger RNA was increased approximately 4- and 6-fold, respectively, in endometriosis compared to eutopic endometrium. Immunohistochemistry of lesions revealed that CXCR4 was expressed in the stroma and epithelium in both endometriosis and control eutopic endometrium. The level of CXCR4 protein expression was significantly higher in all cellular compartments of the endometriotic lesions compared to control endometrium. CXCL12 protein expression was also higher in endometriotic lesions and was greatest in the epithelial compartment. CXCL12 was increased more in the condition media of cultured endometriosis than in controls as measured by enzyme-linked immunosorbent assay. Transwell chamber migration was used to demonstrate 2-fold increased chemoattraction of mouse bone marrow stem cells toward CXCL12 in the endometriotic-conditioned medium compared with eutopic endometrium. Our results indicate that a preferential recruitment of stem cells to endometriosis can explain how endometriosis outcompetes eutopic endometrium in recruiting the limited supply of circulating stem cells. The CXCL12/CXCR4 signaling axis is a potential target for the treatment of endometriosis and its associated disorders.

Kuntai Capsule Inhibited Endometriosis via Inducing Apoptosis in a Rat Model

We evaluated the effectiveness of Kuntai Capsule (KTC) for treating endometriosis using rat model and investigated its preliminary mechanism of action involved. SD rats were implanted with endometrial tissues and treated with KTC for three weeks. Then, laparotomy was performed to examine volume changes of the autografts. The serum levels of TNF-α, IL-6, COX-2, E₂, and P4 were measured through ELISA. TUNEL was performed to analyze the apoptosis on ectopic endometrium. Protein levels of caspases 8, 9, and 3 and cytochrome c in the ectopic and eutopic endometrium were measured by western blotting. Results showed that KTC significantly decreased the volumes of ectopic endometrium. The level of TNF-α increased and E₂ decreased in the KTC treatment groups. TUNEL and western blot assay showed that KTC could induce apoptosis of endometriotic tissues, accompanied with the increased protein expression of caspases 8 and 9, activated caspase-3, and cytochrome c in a dose-dependent manner. However, these protein expression profiles were not affected in eutopic endometrium. Our findings suggest that KTC could inhibit the growth of ectopic endometrial tissue through upregulating the level of TNF-α and its downstream signaling, including caspases and cytochrome c.

Platelets drive smooth muscle metaplasia and fibrogenesis in endometriosis through epithelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation

Smooth muscle metaplasia (SMM) and fibrotic tissues are frequently seen in endometriotic lesions, yet the mechanisms underlying their formation are poorly understood. In this study, we investigated the roles of activated platelets in driving epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT) in endometriosis. Through in vitro experimentations, we found that activated platelets, through the release of TGF-β1 and the induction of TGF-β/Smad signaling pathway, promoted EMT and FMT in endometriosis, resulting in increased cell contractility, collagen production, and ultimately to fibrosis. TGF-β blockade reversed these processes. Prolonged exposure of endometriotic stromal cells to activated platelets induced increased expression of α-SMA as well as markers of differentiated smooth muscle cells. Consequently, endometriotic lesions and their microenvironment contain all the necessary molecular machinery to promote SMM and fibrogenesis. Our results suggest that endometriotic lesions are wounds that undergo repeated injury and healing, highlighting the importance of platelets in the development of endometriosis.

microRNA miR-200b affects proliferation, invasiveness and stemness of endometriotic cells by targeting ZEB1, ZEB2 and KLF4

Endometriosis is characterized by growth of endometrial tissue at ectopic locations. Down-regulation of microRNA miR-200b is observed in endometriosis and malignant disease, driving tumour cells towards an invasive state by enhancing epithelial-to-mesenchymal transition (EMT). miR-200b up-regulation may inhibit EMT and invasive growth in endometriosis. To study its functional impact on the immortalized endometriotic cell line 12Z, the stromal cell line ST-T1b, and primary endometriotic stroma cells, a transient transfection approach with microRNA precursors was employed. Expression of bioinformatically predicted targets of miR-200b was analysed by qPCR. The cellular phenotype was monitored by Matrigel invasion assays, digital-holographic video microscopy and flow cytometry. qPCR revealed significant down-regulation of ZEB1 (P < 0.05) and ZEB2 (P < 0.01) and an increase in E-cadherin (P < 0.01). miR-200b overexpression decreased invasiveness (P < 0.0001) and cell motility (P < 0.05). In contrast, cell proliferation (P < 0.0001) and the stemness-associated side population phenotype (P < 0.01) were enhanced following miR-200b transfection. These properties were possibly due to up-regulation of the pluripotency-associated transcription factor KLF4 (P < 0.05) and require attention when considering therapeutic strategies. In conclusion, up-regulation of miR-200b reverts EMT, emerging as a potential therapeutic approach to inhibit endometriotic cell motility and invasiveness.

Transforming growth factor β1 signaling coincides with epithelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation in the development of adenomyosis in mice

STUDY QUESTION

Do platelets have any role in the development of adenomyosis?

SUMMARY ANSWER

Activated platelets coincide with the release of transforming growth factor (TGF)-β1 and induction of the TGF-β/Smad signaling pathway as well as evidence of epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT) in a mouse model of adenomyosis, resulting ultimately in fibrosis, as in adenomyosis.

WHAT IS KNOWN ALREADY

Both EMT and FMT are known to play vital roles in fibrogenesis in general and in endometriosis in particular. EMT has been implicated in the development of adenomyosis, but this was based primarily on cross-sectional observation. It is unclear as to whether adenomyotic lesions and their microenvironment have the machinery to promote EMT and FMT, resulting ultimately in fibrosis. There has not been any published study on the role of platelets in the development of adenomyosis, even though adenomyotic lesions undergo repeated cycles of tissue injury and repair, which implicates the involvement of platelets and constitutes an environment conducive for fibrogenesis.

STUDY DESIGN, SIZE, DURATION

Adenomyosis was induced in 28 female ICR mice by neonatal dosing of tamoxifen. Another 32 were neonatally dosed without tamoxifen. These mice were sacrificed serially and their tissue samples were subsequently evaluated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Female ICR mice with and without induced adenomyosis were sacrificed in batch at 5, 10, 15, 42 and 60 days of age. The depth of myometrial infiltration of endometrial tissues was assessed and immunohistochemistry analysis of biomarkers of EMT and FMT, as well as TGF-β1, phosphorylated Smad3 (p-Smad3) and markers of proliferation, angiogenesis and extracellular matrix (ECM) deposits was performed in ectopic (for adenomyotic mice) and eutopic (controls) endometrial tissue samples. Masson trichrome and Van Gieson stainings were performed to quantify the extent of fibrosis in lesions. Progesterone receptor isoform B (PR-B) staining also was performed.

MAIN RESULTS AND THE ROLE OF CHANCE

While TGF-β1 immunoreactivity was consistently low in control endometrium, its level was increased dramatically starting from Day 10, along with the extent of platelet aggregation. Staining for TGF-β1 and p-Smad3 increased progressively as adenomyosis progressed, along with markers for proliferation, angiogenesis and ECM deposits. Consistently, staining of vimentin (a marker for stromal or mesenchymal cells) was also increased while that of E-cadherin (a marker for epithelial cells) was reduced. PR-B staining also decreased progressively. Starting from Day 42, α-SMA staining, a marker for myofibroblasts, was elevated in lesions, while in control endometrium, it was negative. Concomitantly, the extent of fibrosis also was increased.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by the use of histochemistry and immunohistochemistry analyses only and the lack of intervention.

WIDER IMPLICATIONS OF THE FINDINGS

Like their endometriotic counterpart, adenomyotic lesions and their microenvironment may contain all the necessary molecular machinery to promote fibrogenesis. Platelet-induced activation of the TGF-β/Smad signaling pathway may be a driving force in EMT and FMT in the development of adenomyosis, leading to fibrosis. This study provides the first piece of evidence that adenomyotic lesions are wounds that undergo repeated injury and healing, and as such, platelets play critical roles in the development of adenomyosis. It suggests the potential for the use of anti-platelet therapy in the treatment of adenomyosis, and also opens a new venue for developing novel biomarkers for diagnostic or prognostic purposes.

STUDY FUNDING/COMPETING INTERESTS

Support for data collection and analysis was provided by grants from the National Science Foundation of China. None of the authors has anything to disclose.

Dysregulation of Lysyl Oxidase Expression in Lesions and Endometrium of Women With Endometriosis

Lysyl oxidases (LOXs) are enzymes involved in collagen deposition, extracellular membrane remodeling, and invasive/metastatic potential. Previous studies reveal an association of LOXs and endometriosis. We aimed to identify the mechanisms activated by upregulation of lysyl oxidases (LOX) in endometriotic cells and tissues. We hypothesized that LOX plays a role in endometriosis by promoting invasiveness and epithelial to mesenchymal transition (EMT).

METHODS

The LOX protein expression levels were measured by immunohistochemistry in lesions and endometrium on a tissue microarray (TMA) and in endometrial biopsies from patients and controls during the window of implantation (WOI). Estradiol regulation of LOX expression was determined by quantitative polymerase chain reaction (qPCR). Proliferation, invasion, and migration assays were performed in epithelial (endometrial epithelial cell), endometrial (human endometrial stromal cell), and endometriotic cell lines (ECL and 12Z). Pathway-focused multiplex qPCR was used to determine transcriptome changes due to LOX overexpression.

RESULTS

LOX protein was differentially expressed in ovarian versus peritoneal lesions. During WOI, LOX levels were higher in luminal epithelium of patients with endometriosis-associated infertility compared to controls. Invasive epithelial cell lines expressed higher levels of LOX than noninvasive ones. Transfection of LOX into noninvasive epithelial cells increased their migration in an LOX inhibitor-sensitive manner. Overexpression of LOX did not fully induce EMT but the expression of genes related to fibrosis and extracellular matrix remodeling were dysregulated.

CONCLUSIONS

This study documents that expression of LOX is differentially regulated in endometriotic lesions and endometrium. A role for LOX in mediating proliferation, migration, and invasion of endometrial and endometriotic cells was observed, which may be implicated in the establishment and progression of endometriotic lesions.

A current view of the role of epigenetic changes in the aetiopathogenesis of endometriosis

The purpose of the study was to examine the role of epigenetic changes in the aetiopathogenesis of endometriosis. The analysis and review of the relevant current literature in English language related to the role of epigenetic changes in the aetiopathogenesis of endometriosis. Epigenetic changes are common denominators for hormonal, immunological and inflammatory aberrations which play a key role in the aetiopathogenesis of endometriosis. Many internal and external factors may cause the different running of the epigenetic mechanism. As yet fully unknown genetic factors may increase the sensitivity of the epigenetic mechanism to various internal and external factors. The breakdown of epigenetic regulation is the main factor initiating the pathogenetic mechanisms for endometriosis formation.

Endometriosis still a challenge

Endometriosis is a debilitating disease with features of chronic inflammation. Endometriosis appears to be one of the most common benign gynecological proliferations in premenopausal women since it is estimated that 10-15% of reproductive aged women suffer from pelvic endometriosis. The biology of endometriosis is unclear. Despite its prevalence, this disease remains poorly understood and current studies prove that there is no relationship between the extent of the disease and its symptomatology. There is no blood test available for the diagnosis of endometriosis. Up to this point, there is no single very successful option for the treatment of endometriosis. Due to the relatively poor efficacy of hormonal therapy for endometriosis, several other experimental therapies are currently undergoing clinical trial.

Transforming growth factor-β induced Warburg-like metabolic reprogramming may underpin the development of peritoneal endometriosis

CONTEXT

TGF-β is believed to play a major role in the etiology of peritoneal endometriosis. In tumors, TGF-β induces the metabolic conversion of glucose to lactate via glycolysis, a process referred to as the "Warburg effect." Lactate increases cell invasion, angiogenesis, and immune suppression, all crucial steps in the development of endometriosis.

OBJECTIVE

The aim of this study was to determine whether TGF-β induces a "Warburg-like" effect in peritoneal endometriosis.

DESIGN

The study was informed by human tissue analysis and cel culture.

SETTING

The study was conducted at the university research institute.

PATIENTS OR OTHER PARTICIPANTS

We studied women undergoing surgical investigation for endometriosis.

INTERVENTIONS

Concentrations of lactate and TGF-β1 in peritoneal fluid (n = 16) were measured by commercial assay. Expression of genes implicated in glycolysis was measured in endometrial and peritoneal biopsies (n = 31) by quantitative RT-PCR and immunohistochemistry. The effect of TGF-β1 on primary human peritoneal mesothelial cells (n = 6) and immortalized mesothelial (MeT-5A) cells (n = 3) was assessed by quantitative RT-PCR, Western blot, and commercial assays.

MAIN OUTCOME MEASURES

Lactate, TGF-β1, and markers of glycolysis were measured.

RESULTS

Concentrations of lactate in peritoneal fluid paralleled those of TGF-β1, being significantly higher in women with endometriosis compared to women without (P < .05). Endometriosis lesions expressed higher levels of glycolysis-associated genes HIF1A, PDK1, and LDHA than eutopic endometrium, and adjacent peritoneum had higher levels of HIF1A and SLC2A1 than peritoneum from women without disease (P < .05 to P < .001). Exposure of mesothelial cells to TGF-β1 increased production of lactate (P < .05), increased HIF1A mRNA (P < .05), and protein, and increased concentrations of mRNAs encoded by glycolysis-associated genes (LDHA, PDK1, SLC2A1; P < .05).

CONCLUSIONS

A change in the metabolic phenotype of endometriosis lesions and peritoneal mesothelium in women with endometriosis may favor development of endometriosis.

MicroRNA and gynecological reproductive diseases

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

Air pollution exposures during adulthood and risk of endometriosis in the Nurses' Health Study II

BACKGROUND

Particulate matter and proximity to large roadways may promote disease mechanisms, including systemic inflammation, hormonal alteration, and vascular proliferation, that may contribute to the development and severity of endometriosis.

OBJECTIVE

Our goal was to determine the association of air pollution exposures during adulthood, including distance to road, particulate matter<2.5 μm, between 2.5 and 10 μm, and <10 μm, (PM2.5, PM10-2.5, PM10), and timing of exposure with risk of endometriosis in the Nurses' Health Study II.

METHODS

Proximity to major roadways and outdoor levels of PM2.5, PM10-2.5, and PM10 were determined for all residential addresses from 1993 to 2007. Multivariable-adjusted time-varying Cox proportional hazard models were used to estimate the relation between these air pollution exposures and endometriosis risk.

RESULTS

Among 84,060 women, 2,486 incident cases of surgically confirmed endometriosis were identified over 710,230 person-years of follow-up. There was no evidence of an association between endometriosis risk and distance to road or exposure to PM2.5, PM10-2.5, or PM10 averaged over follow-up or during the previous 2- or 4-year period.

CONCLUSIONS

Traffic and air pollution exposures during adulthood were not associated with incident endometriosis in this cohort of women.

Differential TGFB1-Signalling in Endometrium from Women with Endometriosis: Importance of Appropriate Housekeeping Genes

Purpose

Endometriosis is characterised by inflammation, fibrosis and scarring, all processes known to involve transforming growth factor-β1 (TGFB1). We examined the expression of genes involved in TGFB1 signalling in epithelium and stroma from eutopic versus ectopic endometrium in women with endometriosis.

Methods

Eutopic and ectopic endometrium was collected during laparoscopy from women with endometriosis (n = 4 proliferative, n = 7 secretory). Laser capture microdissection was used to collect glandular epithelium and CD10-positive stroma from ectopic lesions and eutopic endometrium. Quantitative real-time RT-PCR was used to examine TGFB1, SMAD family member-2 (SMAD2), SMAD3 and SMAD4 mRNA. Expression of mRNA was relative to an RNA-spike. B2M and RPL13A mRNA, and 18S rRNA were also examined; however, expression varied between eutopic and ectopic sites making them unsuitable housekeeping genes in this model.

Results

TGFB1, SMAD3 and SMAD4 mRNA expression was significantly higher in eutopic versus ectopic glandular epithelium; SMAD3 expression was significantly higher in secretory versus proliferative phase eutopic epithelium. TGFB1 expression was significantly higher in eutopic versus ectopic stroma.

Conclusions

Variations in TGFB1, SMAD3 and SMAD4 mRNA expression in eutopic relative to ectopic tissues are consistent with a specific function in eutopic endometrium not replicated in lesions. We suggest that TGFB1-mediated activity is altered in ectopic lesions relative to eutopic endometrium in women with endometriosis, which may affect lesion maintenance. Further research examining the functional consequences of TGFB1 signalling variations is required, including extension of these studies to women without the disorder. Further studies must also carefully consider their housekeeping method and its impact on data and conclusions.

L1 cell adhesion molecule as a potential therapeutic target in murine models of endometriosis using a monoclonal antibody approach

Background/Aims

The neural cell adhesion molecule L1CAM is a transmembrane glycoprotein abnormally expressed in tumors and previously associated with cell proliferation, adhesion and invasion, as well as neurite outgrowth in endometriosis. Being an attractive target molecule for antibody-based therapy, the present study assessed the ability of the monoclonal anti-L1 antibody (anti-L1 mAb) to impair the development of endometriotic lesions invivo and endometriosis-associated nerve fiber growth.

Methods and Results

Endometriosis was experimentally induced in sexually mature B6C3F1 (n=34) and CD-1 nude (n=21) mice by autologous and heterologous transplantation, respectively, of endometrial fragments into the peritoneal cavity. Transplantation was confirmed four weeks post-surgery by invivo magnetic resonance imaging and laparotomy, respectively. Mice were then intraperitoneally injected with anti-L1 mAb or an IgG isotype control antibody twice weekly, over a period of four weeks. Upon treatment completion, mice were sacrificed and endometrial implants were excised, measured and fixed. Endometriosis was histologically confirmed and L1CAM was detected by immunohistochemistry. Endometriotic lesion size was significantly reduced in anti-L1-treated B6C3F1 and CD-1 nude mice compared to mice treated with control antibody (P<0.05). Accordingly, a decreased number of PCNA positive epithelial and stromal cells was detected in autologously and heterologously induced endometriotic lesions exposed to anti-L1 mAb treatment. Anti-L1-treated mice also presented a diminished number of intraperitoneal adhesions at implantation sites compared with controls. Furthermore, a double-blind counting of anti-neurofilament L stained nerves revealed significantly reduced nerve density within peritoneal lesions in anti-L1 treated B6C3F1 mice (P=0.0039).

Conclusions

Local anti-L1 mAb treatment suppressed endometriosis growth in B6C3F1 and CD-1 nude mice and exerted a potent anti-neurogenic effect on induced endometriotic lesions invivo. The findings of this preliminary study in mice provide a strong basis for further testing in invivo models.