Expression of interleukin-8 receptors in endometriosis

Transcriptomics of receptive endometrium in women with sonographic features of adenomyosis

BACKGROUND

Women with uterine adenomyosis seeking assisted reproduction have been associated with compromised endometrial receptivity to embryo implantation. To understand the mechanisms involved in this process, we aimed to compare endometrial transcriptome profiles during the window of implantation (WOI) between women with and without adenomyosis.

METHODS

We obtained endometrial biopsies LH-timed to the WOI from women with sonographic features of adenomyosis (n=10) and controls (n=10). Isolated RNA samples were subjected to RNA sequencing (RNA-seq) by the Illumina NovaSeq 6000 platform and endometrial receptivity classification with a molecular tool for menstrual cycle phase dating (beREADY®, CCHT). The program language R and Bioconductor packages were applied to analyse RNA-seq data in the setting of the result of accurate endometrial dating. To suggest robust candidate pathways, the identified differentially expressed genes (DEGs) associated with the adenomyosis group in the receptive phase were further integrated with 151, 173 and 42 extracted genes from published studies that were related to endometrial receptivity in healthy uterus, endometriosis and adenomyosis, respectively. Enrichment analyses were performed using Cytoscape ClueGO and CluePedia apps.

RESULTS

Out of 20 endometrial samples, 2 were dated to the early receptive phase, 13 to the receptive phase and 5 to the late receptive phase. Comparison of the transcriptomics data from all 20 samples provided 909 DEGs (p<0.05; nonsignificant after adjusted p value) in the adenomyosis group but only 4 enriched pathways (Bonferroni p value < 0.05). The analysis of 13 samples only dated to the receptive phase provided suggestive 382 DEGs (p<0.05; nonsignificant after adjusted p value) in the adenomyosis group, leading to 33 enriched pathways (Bonferroni p value < 0.05). These included pathways were already associated with endometrial biology, such as "Expression of interferon (IFN)-induced genes" and "Response to IFN-alpha". Data integration revealed pathways indicating a unique effect of adenomyosis on endometrial molecular organization (e.g., "Expression of IFN-induced genes") and its interference with endometrial receptivity establishment (e.g., "Extracellular matrix organization" and "Tumour necrosis factor production").

CONCLUSIONS

Accurate endometrial dating and RNA-seq analysis resulted in the identification of altered response to IFN signalling as the most promising candidate of impaired uterine receptivity in adenomyosis.

Bioinformatics approach reveals the key role of C‑X‑C motif chemokine receptor 2 in endometriosis development

Endometriosis is a common gynecological disease, affecting 6‑10% of women of reproductive age. The precise mechanisms underlying the development of endometriosis remain unclear. In the present study, a bioinformatics approach was applied to systematically identify the pathways and genes involved in the development of endometriosis and to discover potential biomarkers. The gene expression profiles of GSE6364, a microarray dataset of endometrial biopsies obtained from women with or without endometriosis, was downloaded from the Gene Expression Omnibus DataSets database that stores original submitter‑supplied records (series, samples and platforms), as well as curated datasets. Differentially expressed gene (DEG) analysis was performed with GEO2R. DAVID was used to analyze the gene ontology enrichment of the DEGs. Gene Set Enrichment Analysis (GSEA) was conducted using the GSEA v3.0 software. Protein‑protein interactions (PPI) were evaluated with the Search Tool for the Retrieval of Interacting Genes, and PPI network visualization was performed with Cytoscape. In addition, Cell Counting kit‑8 and Transwell assays were performed on human endometrial stromal cells (HESCs). A total of 172 DEGs were extracted. Inflammatory response genes were significantly upregulated in the endometriosis tissues and C‑X‑C motif chemokine receptor 2 (CXCR2), was one of the most up‑regulated genes according to DEG analysis. Cell‑based experiments confirmed that CXCR2 promoted the proliferation, migration and invasion of HESCs. In conclusion, a bioinformatics approach combined with in vitro experiments in the present study revealed that CXCR2 may be associated with the development of endometriosis and has potential as a biomarker for the diagnosis of endometriosis.

Endometrial biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, which is a costly, chronic disease that causes pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Currently, there are no non-invasive tests available in clinical practice that accurately diagnose endometriosis. This is the first diagnostic test accuracy review of endometrial biomarkers for endometriosis that utilises Cochrane methodologies, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To determine the diagnostic accuracy of the endometrial biomarkers for pelvic endometriosis, using a surgical diagnosis as the reference standard. We evaluated the tests as replacement tests for diagnostic surgery and as triage tests to inform decisions to undertake surgery for endometriosis.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. To identify trials, we searched the following databases: CENTRAL (2015, July), MEDLINE (inception to May 2015), EMBASE (inception to May 2015), CINAHL (inception to April 2015), PsycINFO (inception to April 2015), Web of Science (inception to April 2015), LILACS (inception to April 2015), OAIster (inception to April 2015), TRIP (inception to April 2015) and ClinicalTrials.gov (inception to April 2015). We searched DARE and PubMed databases up to April 2015 to identify reviews and guidelines as sources of references to potentially relevant studies. We also performed searches for papers recently published and not yet indexed in the major databases. The search strategies incorporated words in the title, abstract, text words across the record and the medical subject headings (MeSH).

SELECTION CRITERIA

We considered published peer-reviewed, randomised controlled or cross-sectional studies of any size that included prospectively collected samples from any population of reproductive-aged women suspected of having one or more of the following target conditions: ovarian, peritoneal or deep infiltrating endometriosis (DIE).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each study and performed a quality assessment. For each endometrial diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis and calculated the estimates of sensitivity and specificity. We considered two or more tests evaluated in the same cohort as separate data sets. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient data were available. The predetermined criteria for a clinically useful test to replace diagnostic surgery was one with a sensitivity of 94% and a specificity of 79%. The criteria for triage tests were set at sensitivity at or above 95% and specificity at or above 50%, which in case of negative results rules out the diagnosis (SnOUT test) or sensitivity at or above 50% with specificity at or above 95%, which in case of positive result rules in the diagnosis (SpIN test).

MAIN RESULTS

We included 54 studies involving 2729 participants, most of which were of poor methodological quality. The studies evaluated endometrial biomarkers either in specific phases of the menstrual cycle or outside of it, and the studies tested the biomarkers either in menstrual fluid, in whole endometrial tissue or in separate endometrial components. Twenty-seven studies evaluated the diagnostic performance of 22 endometrial biomarkers for endometriosis. These were angiogenesis and growth factors (PROK-1), cell-adhesion molecules (integrins α3β1, α4β1, β1 and α6), DNA-repair molecules (hTERT), endometrial and mitochondrial proteome, hormonal markers (CYP19, 17βHSD2, ER-α, ER-β), inflammatory markers (IL-1R2), myogenic markers (caldesmon, CALD-1), neural markers (PGP 9.5, VIP, CGRP, SP, NPY, NF) and tumour markers (CA-125). Most of these biomarkers were assessed in single studies, whilst only data for PGP 9.5 and CYP19 were available for meta-analysis. These two biomarkers demonstrated significant diversity for the diagnostic estimates between the studies; however, the data were too limited to reliably determine the sources of heterogeneity. The mean sensitivities and specificities of PGP 9.5 (7 studies, 361 women) were 0.96 (95% confidence interval (CI) 0.91 to 1.00) and 0.86 (95% CI 0.70 to 1.00), after excluding one outlier study, and for CYP19 (8 studies, 444 women), they were were 0.77 (95% CI 0.70 to 0.85) and 0.74 (95% CI 0.65 to 84), respectively. We could not statistically evaluate other biomarkers in a meaningful way. An additional 31 studies evaluated 77 biomarkers that showed no evidence of differences in expression levels between the groups of women with and without endometriosis.

AUTHORS' CONCLUSIONS

We could not statistically evaluate most of the biomarkers assessed in this review in a meaningful way. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Although PGP 9.5 met the criteria for a replacement test, it demonstrated considerable inter study heterogeneity in diagnostic estimates, the source of which could not be determined. Several endometrial biomarkers, such as endometrial proteome, 17βHSD2, IL-1R2, caldesmon and other neural markers (VIP, CGRP, SP, NPY and combination of VIP, PGP 9.5 and SP) showed promising evidence of diagnostic accuracy, but there was insufficient or poor quality evidence for any clinical recommendations. Laparoscopy remains the gold standard for the diagnosis of endometriosis, and using any non-invasive tests should only be undertaken in a research setting. We have also identified a number of biomarkers that demonstrated no diagnostic value for endometriosis. We recommend that researchers direct future studies towards biomarkers with high diagnostic potential in good quality diagnostic studies.

TLR4 Activation Promotes the Secretion of IL-8 Which Enhances the Invasion and Proliferation of Endometrial Stromal Cells in an Autocrine Manner via the FAK Signal Pathway

PROBLEM

Chronic inflammation is important for the occurrence of endometriosis, but the molecular mechanisms are still poorly understood. TLR4 is not only expressed on immune cells but is also present in the human endometrium, and its regulation might be crucial for the pathogenesis of endometriosis.

METHOD OF STUDY

In this study, the expression of TLR4 in normal, eutopic endometrium, and ectopic tissues was analyzed by immunohistochemistry. The expression of the key molecules in endometrial stromal cells (ESCs) was assessed by in-cell Western assays. The invasion of eutopic ESCs from patients with endometriosis was evaluated by Matrigel invasion assay. The effects of CXCL8 on the proliferation of ESCs in vitro were assessed using BrdU assays.

RESULTS

We found that the expression of TLR4 is higher in the eutopic endometrium than the normal endometrium and that ectopic tissue had the highest level of expression. TLR4 activation stimulated IL-8 secretion and the expression of its receptor CXCR1 in ESCs by activating p38/ERK, but not JNK and NK-κB signal pathways. IL-8 could enhance the invasion and proliferation of ESCs through the FAK signal pathway, and these effects could be abolished by an anti-CXCL8 neutralizing antibody or by a FAK inhibitor.

Lipoxin A4 suppresses the development of endometriosis in an ALX receptor-dependent manner via the p38 MAPK pathway

BACKGROUND AND PURPOSE

Lipoxins can function as endogenous 'breaking signals' in inflammation and play important roles in the progression of endometriosis. In this study, we further investigated the molecular mechanism by which lipoxin A4 (LXA4 ) suppresses the development of endometriosis.

EXPERIMENTAL APPROACH

Primary endometriotic stromal cells (ESCs) were treated with IL-1β, or pre-incubated with LXA4 before incubation with IL-1β. The LXA4 receptor (ALX receptor) antagonist Boc-2 and gene-silencing approaches were used to study the involvement of the ALX receptor in anti-inflammatory signalling responses in ESCs. An animal model of endometriosis was induced in BALB/c mice by i.p. injection of an endometrium-rich fragment.

KEY RESULTS

Decreased levels of LXA4 and 15-LOX-2 expression but increased expression of AXL receptors were observed in endometriotic tissues. LXA4 inhibited the release of inflammatory factors and phosphorylation of p38 MAPK in IL-1β-induced ESCs, an effect mediated by ALX receptors. LXA4 inhibited the proliferation of ESCs, as indicated by reduced DNA replication, caused G0 /G1 phase cell cycle arrest and down-regulated the expression of proliferating cell nuclear antigen in ESCs. LXA4 also attenuated the invasive activity of ESCs mainly by suppressing the expression and activity of MMP-9. In vivo, we further confirmed that LXA4 could inhibit the progression of endometriosis by acting as an anti-inflammatory.

CONCLUSIONS AND IMPLICATIONS

LXA4 exerted anti-inflammatory, anti-proliferative and anti-invasive effects on endometriosis through a mechanism that involved down-regulating the activities of p38 MAPK, which was mediated by ALX receptors.

Association of the neutrophil-to-lymphocyte ratio and CA 125 with the endometriosis score

Objective

To evaluate the association between the severity of endometriosis and the preoperative neutrophil-to-lymphocyte ratio (NLR) and serum level of cancer antigen 125 (CA 125).

Methods

Data were obtained from the medical records of 419 patients who underwent laparoscopic conservative surgery for ovarian endometrioma between April 2005 and March 2013. Each patient's preoperative complete blood count was recorded and the endometriosis score was assessed.

Results

The endometriosis score was not associated with either the NLR or the serum level of CA 125. The endometriosis score was negatively related to preoperative hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration. The only positive association was between NLR and the patients' age. NLR and preoperative serum anti-Müllerian hormone level were found to be negatively related.

Conclusion

The severity of endometriosis was not associated with the serum level of CA 125 or the NLR. The presence of a negative correlation between the severity of endometriosis and red blood cell dynamics needs further investigation.

Mechanical signaling in reproductive tissues: mechanisms and importance

The organs of the female reproductive system are among the most dynamic tissues in the human body, undergoing repeated cycles of growth and involution from puberty through menopause. To achieve such impressive plasticity, reproductive tissues must respond not only to soluble signals (hormones, growth factors, and cytokines) but also to physical cues (mechanical forces and osmotic stress) as well. Here, we review the mechanisms underlying the process of mechanotransduction-how signals are conveyed from the extracellular matrix that surrounds the cells of reproductive tissues to the downstream molecules and signaling pathways that coordinate the cellular adaptive response to external forces. Our objective was to examine how mechanical forces contribute significantly to physiological functions and pathogenesis in reproductive tissues. We highlight how widespread diseases of the reproductive tract, from preterm labor to tumors of the uterus and breast, result from an impairment in mechanical signaling.

Increased oxidation-related glutathionylation and carbonic anhydrase activity in endometriosis

This study examined the possible involvement of carbonic anhydrase activation in response to an endometriosis-related increase in oxidative stress. Peripheral blood samples obtained from 27 healthy controls and 30 endometriosis patients, classified as having endometriosis by histological examination of surgical specimens, were analysed by multiple immunoassay and carbonic anhydrase activity assay. Red blood cells (RBC) were analysed for glutathionylated protein (GSSP) content in the membrane, total glutathione (GSH) in the cytosol and carbonic anhydrase concentration and activity. In association with a membrane increase of GSSP and a cytosolic decrease of GSH content in endometriosis patients, carbonic anhydrase significantly increased (P < 0.0001) both monomerization and activity compared with controls. This oxidation-induced activation of carbonic anhydrase was positively and significantly correlated with the GSH content of RBC (r = 0.9735, P < 0.001) and with the amount of the 30-kDa monomer of carbonic anhydrase (r = 0.9750, P < 0.001). Because carbonic anhydrase activation is implied in many physiological and biochemical processes linked to pathologies such as glaucoma, hypertension, obesity and infections, carbonic anhydrase activity should be closely monitored in endometriosis. These data open promising working perspectives for diagnosis and treatment of endometriosis and hopefully of other oxidative stress-related diseases. Endometriosis is a chronic disease associated with infertility and local inflammatory response, which is thought to spread rapidly throughout the body as a systemic subclinical inflammation. One of the causes in the pathogenesis/evolution of endometriosis is oxidative stress, which occurs when reactive oxygen species are produced faster than the endogenous antioxidant defence systems can neutralize them. Once produced, reactive oxygen species can alter the morphological and functional properties of endothelial cells, including permeability and adhesion molecule expression, thus contributing to ongoing inflammation. Due to their main cellular functions--delivery of O2 from lung to tissue and removal of CO2 from tissue to lung--red blood cells (RBC) are exposed to oxidative stress. Carbon dioxide in tissue capillaries diffuses into red cells, where it is rapidly hydrated by the action of cytosolic carbonic anhydrase. Analysis of the oxidation status of endometriotic RBC membranes showed a high content of glutathionylated proteins, indicating pre-existing oxidation-related alterations. The increase in glutathionylated proteins was correlated to increased carbonic anhydrase activity in endometriotic RBC compared with healthy controls. Carbonic anhydrase is a family of metalloenzymes involved in many physiological processes such as acid-base homeostasis, respiration, carbon dioxide and ion transport, and bone resorption, and in the regulation of ureagenesis, gluconeogenesis, lipogenesis and tumourigenesis. Due to the potential implication of carbonic anhydrase activation in many pathologies, such as glaucoma, hypertension, obesity and infections, carbonic anhydrase activity should be closely monitored in endometriosis to prevent possible complications and/or worsening of related conditions.

Effect of acupuncture on CXCL8 receptors in rats suffering from embryo implantation failure

To observe the effect of acupuncture on CXCL8 receptors (CXCR1 and CXCR2) in rat endometrium experiencing embryo implantation failure, 72 pregnant rats were randomly divided into four groups: normal group (N), embryo implantation failure group (M), acupuncture treatment group (A), and progestin treatment group (W). Then the rats in each group were equally randomized into a day-6 (D6) group, a day-8 (D8) group, and a day-10 (D10) group. The rats in group M, group A, and group W were treated with mifepristone-sesame oil solution on day 1, while the rats in group N were injected with the same amount of sesame oil. Meanwhile, "Housanli" and "Sanyinjiao" were selected for acupuncture. From day 1 to the time of death, the rats in group A were fastened up and then acupuncture was administered while the rats in group N and group M were only fixed, and the rats in group W were given progestin. The number of implanted embryos was calculated. The expression of CXCR1 and CXCR2 in rat endometrium was detected by immunohistochemistry, Western blotting and real-time PCR. Compared to group N, the average number of implanted embryos, the protein and mRNA expression of CXCR1 (D6, D8 and D10), and the protein and mRNA expression of CXCR2 (D8 and D10) in rat endometrium were significantly decreased in group M. Compared to group M, there was significant elevation in the average number of implanted embryos, the protein expression (D6, D8 and D10) and mRNA expression (D8) of CXCR1 in rat endometrium of group A, and the protein expression (D8 and D10) and mRNA expression (D8) of CXCR2 in rat endometrium of group W. These findings indicated that acupuncture can increase the number of implanted embryos in rats of embryo implantation failure, which may be relevant with up-regulation the expression of CXCR1 and CXCR2 at maternal-fetal interface of rats with embryo implantation failure.

Copeptin is associated with the severity of endometriosis

PURPOSE

Endometriosis is defined as the presence of endometrial glands and stroma in ectopic locations and may be associated with local and systemic inflammatory processes. Copeptin is elevated in acute and chronic inflammation conditions. The aim of the present study was to determine whether serum copeptin levels were altered in women with endometriosis and played a role in the pathophysiology of the disease.

METHODS

A total of 86 women were recruited for this case-control study. 50 patients with surgically proven endometriosis were included, while 36 patients without endometriosis comprised the control group. Patients were classified as having minimal, mild, moderate and severe disease in accordance with American Society of Reproductive Medicine revised classification. Two subgroups were formed by combining patients with minimal and mild disease and with moderate and severe disease (Stage 1-2, stage 3-4; respectively). Levels of copeptin, tumor markers (CA-125, CA-19-9, CA-15-3) and C-reactive protein in serum were measured.

RESULTS

Serum copeptin, CA-125, CA-15-3 and CA-19-9 levels were higher in the endometriosis group (p: 0.002; 0.001; 0.017; 0.015; respectively). Copeptin and CA-19-9 levels were significantly higher in stage 3-4 group as compared to stage 1-2 group (p: 0.004; 0.036 respectively). Serum copeptin levels were positively correlated with stage of the disease and size of endometriomas. ROC analysis revealed that CA-125 had the highest AUC for predicting endometriosis (0.938; 95 % confidence interval 0.882-0.993; p: 0.001).

CONCLUSIONS

Serum copeptin levels were significantly higher in patients with endometriosis as compared to healthy controls. Moreover, severity of the disease was correlated with serum copeptin levels.

Chemokines in the pathogenesis of endometriosis and infertility

Endometriosis is a chronic benign disease that affects women of reproductive age causing abdominal pain and infertility. Its pathogenesis remains obscure despite all the research conducted over the past 100 years. However, there is a consensus among the specialists that the basis of its pathophysiology would be multifactorial. Many publications have demonstrated that chemokines are somehow associated with the development of endometriosis and infertility. In this study, we reviewed all PubMed literature using MeSH terms "chemokines" and "endometriosis" as well as "chemokines" and "female infertility" to establish what we know and what we do not yet know about this relationship.

Seminal plasma induces angiogenic chemokine expression in cervical cancer cells and regulates vascular function

Cervical cancer is one of the leading gynecological malignancies in women. We have recently shown that seminal plasma (SP) can regulate the inflammatory cyclooxygenase-prostaglandin pathway and enhance the growth of cervical epithelial tumours in vivo by promoting cellular proliferation and alteration of vascular function. This study investigated the molecular mechanism whereby SP regulates vascular function using an in vitro model system of HeLa cervical adenocarcinoma cells and human umbilical vein endothelial cells (HUVECs). We found that SP rapidly enhanced the expression of the angiogenic chemokines, interleukin (IL)-8 and growth regulated oncogene alpha (GRO) in HeLa cells in a time-dependent manner. We investigated the molecular mechanism of SP-mediated regulation of IL-8 and GRO using a panel of chemical inhibitors of cell signalling. We found that treatment of HeLa cells with SP elevated expression of IL-8 and GRO by transactivation of the epidermal growth factor receptor, activation of extracellular signal-regulated kinase and induction of cyclooxygenase enzymes and nuclear factor kappa B. We investigated the impact of IL-8 and GRO, released from HeLa cells after treatment with SP, on vascular function using a co-culture model system of conditioned medium (CM) from HeLa cells, treated with or without SP, and HUVECs. We found that CM from HeLa cells induced the arrangement of endothelial cells into a network of tube-like structures via the CXCR2 receptor on HUVECs. Taken together our data outline a molecular mechanism whereby SP can alter vascular function in cervical cancers via the pro-angiogenic chemokines, IL-8 and GRO.

The expression of interleukin-8 and interleukin-8 receptors in endometrial carcinoma

Interleukin-8 (IL-8) is a pro-inflammatory cytokine which exerts its effects via binding to 2 receptors, CXCR1 and CXCR2 and is known to promote angiogenesis, mitogenesis and motogenesis in cancer. IL-8 is over expressed in endometrial carcinoma, but the expression of CXCR1 and CXCR2 in endometrial carcinoma has not been previously investigated. The aim of this study was to determine the expression of IL-8 receptors in endometrial carcinoma. The expression of CXCR1 and CXCR2 was studied in endometrial carcinomas and normal endometrium by immunohistochemistry in 101 tumours. IL-8 and IL-8 receptor expression was also studied by Real-time quantitative PCR (RT-qPCR) in 17 tumours in comparison to normal endometrium. The expression profile was correlated to the clinico-pathological features of the tumours. Immunohistochemistry showed CXCR1 and CXCR2 were expressed in all cases of endometrial carcinoma, with CXCR1 showing stronger expression. There was a statistically significant correlation between CXCR2 staining intensity and tumour grade (P=0.012) and disease free survival (P=0.015) independently. On RT-qPCR, 14/17, 15/17 and 16/17 tumours showed significant increase in IL-8, CXCR1 and CXCR2 expression levels in comparison to normal endometrium, with median fold increase of 42-fold, 51-fold and 27-fold, respectively. This is the first report of the expression of IL-8 receptors in endometrial carcinoma and the results show an association between IL-8 and IL-8 receptors and the pathogenesis of endometrial carcinoma, and represent potential prognostic biomarkers and therapeutic targets.

CXCL8 enhances proliferation and growth and reduces apoptosis in endometrial stromal cells in an autocrine manner via a CXCR1-triggered PTEN/AKT signal pathway

BACKGROUND

Chemokine CXCL8 (also known as IL-8) has been identified as a potential regulator of endometrial stromal cells (ESCs), but it is unclear how CXCL8 regulates the survival of ESCs in the pathogenesis of endometriosis.

METHODS

We assessed the secretion of CXCL8 by enzyme-linked immunosorbent assays and the expression of its receptors, CXCR1 and CXCR2, by in-cell Western assay and immunohistochemistry. The effects of CXCL8 on the activation or expression of various cell mediators were also investigated by in-cell Western assay. The effects of CXCL8 on the proliferation, growth and apoptosis of ESCs in vitro were assessed by BrdU assays, cell counts and annexin V labeling, respectively.

RESULTS

Secretion of CXCL8 and expression of CXCR1 in the eutopic ESCs from women with endometriosis were significantly higher than that in control ESCs, but the expression of CXCR2 showed no significant difference between these two cell types. CXCL8 stimulated proliferation and growth and reduced apoptosis of ESCs in an autocrine manner, and these effects were abolished by anti-human CXCL8 and CXCR1 neutralizing antibodies and by a PI3K/Akt inhibitor. Moreover, CXCL8 up-regulated the expression of the anti-apoptotic proteins, survivin and Bcl-2, inhibited the expression of the Phosphatase and tensin homolog (PTEN) and activated the phosphorylation of Akt.

CONCLUSIONS

This study suggests that CXCL8 and CXCR1 are involved in the pathogenesis of endometriosis by up-regulating proliferation and growth and restricting apoptosis in ESCs by activating the PTEN/Akt pathway and mediating the expression of survivin and Bcl-2.

Abnormal regulation of chemokine TECK and its receptor CCR9 in the endometriotic milieu is involved in pathogenesis of endometriosis by way of enhancing invasiveness of endometrial stromal cells

The chemokine thymus-expressed chemokine (TECK), which regulates T-cell development and tissue-specific homing, has been identified as a potential contributor to the pathogenesis and progression of endometriosis. Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD), an air pollutant, and estrogen also appear to be involved in endometriosis. Both endometrial stromal cells (ESCs) and the combination of 17beta-estradiol and TCDD increase the secretion of TECK in the endometriosis-associated cells and promote the invasiveness of ESCs by increasing expression of matrix metalloproteinase (MMP)-2 and MMP-9. Anti-TECK neutralizing antibodies can effectively inhibit the invasiveness of ESCs and the expression of MMP-2 and MMP-9 in the cells. Interestingly, the expression of chemokine C receptor 9 (CCR9) and its ligand TECK increases significantly in the endometriotic milieu of patients with endometriosis. Therefore, the over-expressed TECK interacts with CCR9 on the ESCs in the endometriotic milieu, which may contribute to the onset and progression of endometriosis.

Evaluation of erythrocyte band 3 phosphotyrosine level, glutathione content, CA-125, and human epididymal secretory protein E4 as combined parameters in endometriosis

OBJECTIVE

To investigate the biochemical parameters of the erythrocyte response to diamide-induced oxidative stress, alone or as adjuncts to serum values of CA-125 and human epididymal secretory protein E4 (HE4), in the diagnosis and study of endometriosis.

SETTING

University of Padova.

DESIGN

Prospective study.

PATIENT(S)

Forty-five patients of reproductive age undergoing laparoscopy.

INTERVENTION(S)

All women were studied for endometriotic foci during laparoscopic surgery. Forty-one had laparoscopically and histologically confirmed endometriosis, and four did not. Twenty women with confirmed endometriosis were reassessed 1-4 months later.

MAIN OUTCOME MEASURE(S)

CA-125 and HE4 and two new parameters evaluated in erythrocytes after diamide-induced stress, that is, band 3 tyrosine phosphorylation (Tyr-P) level and decrease in total glutathione content (ΔGSH), were assessed in all patients.

RESULT(S)

In association with serum CA-125 levels but not with HE4, diamide-related erythrocyte band 3 Tyr-P and ΔGSH were significantly higher in patients with endometriosis and were able to discriminate with high sensitivity and specificity between patients before and after surgery.

CONCLUSION(S)

Endometriosis is associated with an increase in systemic oxidative stress, affecting the antioxidative defenses of circulating erythrocytes. All related implications, including evaluation of other oxidative stress-related changes, warrant further study.

Prostaglandin F(2alpha)-F-prostanoid receptor regulates CXCL8 expression in endometrial adenocarcinoma cells via the calcium-calcineurin-NFAT pathway

Pro-inflammatory mediators, like prostaglandin (PG) and chemokines, promote tumourigenesis by enhancing cell proliferation, migration of immune cells and recruitment of blood vessels. Recently we showed elevated expression of the chemokine (C-X-C motif) receptor 2 (CXCR2) in endometrial adenocarcinomas localized to neutrophils and neoplastic epithelial and vascular cells. Furthermore we found that PGF_2α-F-prostanoid (FP) receptor regulates the expression of the CXCR2 ligand CXCL1, to promote neutrophil chemotaxis in endometrial adenocarcinomas. In the present study we identified another CXCR2 ligand, CXCL8 as a target for PGF_2α-FP receptor signalling which enhances epithelial cell proliferation in endometrial adenocarcinoma cells in vitro and in nude mice in vivo. We found that PGF_2α-FP receptor interaction induces CXCL8 expression in endometrial adenocarcinoma cells via the protein kinase C–calcium–calcineurin–NFAT signaling pathway. Promoter analysis revealed that CXCL8 transcriptional activation by PGF_2α signaling is mediated by cooperative interactions between the AP1 and NFAT binding sites. Furthermore, PGF_2α via the FP receptor induced the expression of the regulator of calcineurin 1 isoform 4 (RCAN1-4) via the calcineurin/NFAT pathway in a reciprocal manner to CXCL8. Using an adenovirus to overexpress RCAN1-4, we found that RCAN1-4 is a negative regulator of CXCL8 expression in endometrial adenocarcinoma cells. Taken together our data have elucidated the molecular and cellular mechanism whereby PGF_2α regulates CXCL8 expression via the FP receptor in endometrial adenocarcinomas and have highlighted RCAN1-4 as a negative regulator of CXCL8 expression which may be exploited therapeutically to inhibit CXCL8-mediated tumour development.

Inflammatory pathways in female reproductive health and disease

Inflammation involves alterations to vascular and immune cell function. It is well recognised that many physiological reproductive events such as ovulation, menstruation, implantation and onset of labour display hallmark signs of inflammation. These are orchestrated by specific molecular pathways involving a host of growth factors, cytokines, chemokines and lipid mediators. Resumption of normal reproductive function involves prompt and proper resolution of these inflammatory pathways. Recent literature confirms that resolution of inflammatory pathways involves specific biochemical events that are activated to re-establish homeostasis in the affected tissue. Moreover, initiation and maintenance of inflammatory pathways are the key components of many pathologies of the reproductive tract and elsewhere in the body. The onset of reproductive disorders or disease may be the result of exacerbated activation and maintenance of inflammatory pathways or their dysregulated resolution. This review will address the role of inflammatory events in normal reproductive function and its pathologies.

Evaluation of serum and urinary angiogenic factors in patients with endometriosis

PROBLEM

The aim of this study was to evaluate serum and urinary levels of vascular endothelial growth factors, tumor necrosis factor-alpha (TNF-alpha), and soluble fms-like tyrosine kinase (sFlt-1) in patients with endometriosis.

METHOD OF STUDY

During surgery for pelvic pain, pelvic mass or infertility, serum and urine were collected. Of 70 patients, 46 had histology-proven endometriosis and 24 patients without endometriosis participated as controls.

RESULTS

Serum TNF-alpha levels and urinary sFlt-1 levels corrected for creatinine excretion were significantly increased in the endometriosis group (P=0.001 and P=0.011 respectively). Serum sFlt-1 levels and urinary sFlt-1 levels corrected for creatinine were significantly higher in patients with minimal-to-mild disease (P=0.014 and P=0.015 respectively), where serum TNF-alpha levels were increased in moderate-to-severe endometriosis (P<0.001).

CONCLUSION

The pathogenesis of minimal-to-mild endometriosis and moderate-to-severe endometriosis seems to be different. Increased sFlt-1 levels in serum and urine of minimal-to-mild disease indicate that sFlt-1 may have an important role in inhibiting angiogenic process of the disease.

Combination of 17β-estradiol with the environmental pollutant TCDD is involved in pathogenesis of endometriosis via up-regulating the chemokine I-309–CCR8

OBJECTIVE

To explore the effects of the combined E(2) with the environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on CCR8-I-309 expression by the endometriotic lesion-associated cells in the pathogenesis of endometriosis.

DESIGN

Prospective laboratory study.

SETTING

University hospital.

PATIENT(S)

Chinese women with endometriosis.

INTERVENTION(S)

The endometriotic tissue and matched eutopic endometrium were collected. Endometrial stromal cells (ESCs), HPMC, and U937 cells were treated with 17beta-E(2) or TCDD. The ESCs were stimulated with I-309.

MAIN OUTCOME MEASURE(S)

The expression of CCR8 in tissues was analyzed by reverse transcription-polymerase chain reaction and immunohistochemistry. The effect of I-309 on integrin beta1 and alphavbeta3 expression intensity was analyzed by flow cytometry, and the chemotactic activity of I-309 on the ESC was explored by chemotactic assay. Concentration of I-309 in the culture supernatant was quantified by enzyme-linked immunosorbent assay.

RESULT(S)

CCR8 was overexpressed in the endometriotic tissue. I-309 promoted the expression of integrin beta1. Estradiol and TCDD up-regulated CCR8 expression by ESCs. Estradiol magnified the stimulatory effect of TCDD on I-309 secretion by U937. The interaction of HPMC and U937 cells promoted I-309 secretion.

CONCLUSION(S)

These findings imply that the combination of 17beta-E(2) with the environmental pollutant TCDD is involved in the pathogenesis of endometriosis via up-regulating the chemokine CCR8-I-309.

Laser capture microdissection and cDNA array analysis of endometrium identify CCL16 and CCL21 as epithelial-derived inflammatory mediators associated with endometriosis

BACKGROUND

Understanding the pathophysiology of chemokine secretion in endometriosis may offer a novel area of therapeutic intervention. This study aimed to identify chemokines differentially expressed in epithelial glands in eutopic endometrium from normal women and those with endometriosis, and to establish the expression profiles of key chemokines in endometriotic lesions.

METHODS

Laser capture microdissection isolated epithelial glands from endometrial eutopic tissue from women with and without endometriosis in the mid-secretory phase of their menstrual cycles. Gene profiling of the excised glands used a human chemokine and receptor cDNA array. Selected chemokines were further examined using real-time PCR and immunohistochemistry.

RESULTS

22 chemokine/receptor genes were upregulated and two downregulated in pooled endometrial epithelium of women with endometriosis compared with controls. CCL16 and CCL21 mRNA was confirmed as elevated in some women with endometriosis compared to controls on individual samples. Immunoreactive CCL16 and CCL21 were predominantly confined to glands in eutopic and ectopic endometrium: leukocytes also stained. Immunoreactive CCL16 was overall higher in glands in ectopic vs. eutopic endometrium from the same woman (P < 0.05). Staining for CCL16 and CCL21 was highly correlated in individual tissues.

CONCLUSION

This study provides novel candidate molecules and suggests a potential local role for CCL16 and CCL21 as mediators contributing to the inflammatory events associated with endometriosis.

The role of endometrium in endometriosis

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

Effects of combined 17beta-estradiol with TCDD on secretion of chemokine IL-8 and expression of its receptor CXCR1 in endometriotic focus-associated cells in co-culture

BACKGROUND

Chemokines play an important role in the pathogenesis of endometriosis. In the present study, the transcription of 18 chemokine receptors in eutopic endometrium and ectopic tissue with endometriosis was first analysed by RT-PCR. Dioxin, an air pollutant, and estrogen are reported to be associated with endometriosis. The regulatory mechanisms of dioxin and estrogen in the expression of CXCR1/IL-8 in the corresponding cells will help in elucidating roles of the chemokine in the aetiology of endometriosis.

METHODS AND RESULTS

CXCR1, a type of chemokine receptor, was over-expressed in endometriotic tissue. The high translation of the receptor and its ligand, interleukin (IL-8), in endometriotic tissue was then demonstrated by immunochemistry. Estradiol and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alone inhibited expression of CXCR1, whereas the combination of estradiol with TCDD up-regulated the expression. TCDD promoted IL-8 secretion by human pelvic mesothelial cells (HPMC), and 17beta-estradiol magnified the stimulatory effect. Both 17beta-estradiol and TCDD alone inhibited IL-8 secretion of U937 (a cell line of monocyte), but combination of 17beta-estradiol and TCDD had no further inhibitory effect. The co-culture of endometrial stromal cells (ESC) with HPMC produced more IL-8 than respective or total production of either of the cells alone, and estradiol played a synergistic stimulatory role with TCDD in IL-8 secretion of the co-culture. Interaction of HPMC and the monocytes significantly stimulated IL-8 secretion, suggesting a main resource of IL-8 in peritoneal cavity with endometriosis. TCDD promoted IL-8 secretion by HPMC-U937 co-culture, but exerted a contrary effect for IL-8 secretion when combined with estradiol.

CONCLUSION

Estradiol and TCDD in the peritoneal cavity can lead to a persistent and serious inflammation, which gives a new insight into the interactions of estrogen and TCDD in endometriosis.

Expression of interleukin-8 receptors in patients with adenomyosis

OBJECTIVE

To investigate the expression of interleukin-8 (IL-8) receptors CXCR1 and CXCR2 in adenomyosis.

DESIGN

Comparative immunohistochemical study.

SETTING

Academic medical center.

PATIENT(S)

Thirty women who had undergone hysterectomy and were proved histopathologically to have adenomyosis, and 27 women without adenomyosis who had a hysterectomy for nonendometrial pathology such as leiomyomata or benign ovarian cysts.

INTERVENTION(S)

Tissue sections were immunostained with murine monoclonal anti-human CXCR1 and CXCR2 antibodies.

MAIN OUTCOME MEASURE(S)

Microscopic evaluation to assess the presence and localization of CXCR1 and CXCR2 throughout the menstrual cycle in both eutopic endometrial and adenomyotic tissues of women with adenomyosis and compare it with normal endometrium.

RESULT(S)

In eutopic endometrium of women with adenomyosis, proliferative phase samples showed higher epithelial CXCR1 and CXCR2 staining intensity compared with proliferative phase samples of normal endometrium. Adenomyosis foci expressed higher epithelial CXCR1 compared with the homologous eutopic endometrium and normal endometrium. On the other hand, adenomyosis foci and the homologous eutopic endometrium showed similar epithelial CXCR2 staining intensity, and this expression was higher than the normal controls.

CONCLUSION(S)

Intrinsic abnormalities concerning IL-8 and its receptor system may be present in the eutopic endometrium of women affected by adenomyosis. These findings suggest that IL-8 receptors may be involved in the pathogenesis and/or pathophysiology of adenomyosis.

Transcriptional characterizations of differences between eutopic and ectopic endometrium

Endometriosis, defined as the presence of endometrial glandular and stromal cells outside the uterine cavity, is a common gynecological disease with poorly understood pathogenesis. Using laser capture microdissection and a cDNA microarray with 9600 genes/expressed sequence tags (ESTs), we have conducted a comprehensive profiling of gene expression differences between the ectopic and eutopic endometrium taken from 12 women with endometriosis adjusted for menstrual phase and the location of the lesions. With dye-swapping and replicated arrays, we found 904 genes/ESTs that are differentially expressed. We validated the gene expression using real-time RT-PCR. We found that the expression patterns of these genes/ESTs correctly classified the 12 patients into ovarian and nonovarian endometriosis. We identified gene clusters that are location-specific. In addition, we identified several biological themes using Expression Analysis Systematic Explorer. Finally, we identified 79 pathways with over 100 genes with known functions, which include oxidative stress, focal adhesion, Wnt signaling, and MAPK signaling. The identification of these genes and their associated pathways provides new insight. Our findings will stimulate future investigations on molecular genetic mechanisms underlying the pathogenesis of endometriosis.