Expression and regulation of CCR1 in peritoneal macrophages from women with and without endometriosis

Peritoneal immune microenvironment of endometriosis: Role and therapeutic perspectives

Endometriosis, an estrogen-dependent chronic inflammatory disease characterized by the growth of endometrium-like tissues outside the uterine cavity, affects 10% of reproductive-age women. Although the pathogenesis of endometriosis is uncertain, it is widely accepted that retrograde menstruation results in ectopic endometrial tissue implantation. Given that not all women with retrograde menstruation develop endometriosis, immune factors have been hypothesized to affect the pathogenesis of endometriosis. In this review, we demonstrate that the peritoneal immune microenvironment, including innate immunity and adaptive immunity, plays a central role in the pathogenesis of endometriosis. Current evidence supports the fact that immune cells, such as macrophages, natural killer (NK) cells, dendritic cells (DCs), neutrophils, T cells, and B cells, as well as cytokines and inflammatory mediators, contribute to the vascularization and fibrogenesis of endometriotic lesions, accelerating the implantation and development of ectopic endometrial lesions. Endocrine system dysfunction influences the immune microenvironment through overexpressed estrogen and progesterone resistance. In light of the limitations of hormonal therapy, we describe the prospects for potential diagnostic biomarkers and nonhormonal therapy based on the regulation of the immune microenvironment. Further studies are warranted to explore the available diagnostic biomarkers and immunological therapeutic strategies for endometriosis.

Identification of 371 genetic variants for age at first sex and birth linked to externalising behaviour

Age at first sexual intercourse and age at first birth have implications for health and evolutionary fitness. In this genome-wide association study (age at first sexual intercourse, N = 387,338; age at first birth, N = 542,901), we identify 371 single-nucleotide polymorphisms, 11 sex-specific, with a 5-6% polygenic score prediction. Heritability of age at first birth shifted from 9% [CI = 4-14%] for women born in 1940 to 22% [CI = 19-25%] for those born in 1965. Signals are driven by the genetics of reproductive biology and externalising behaviour, with key genes related to follicle stimulating hormone (FSHB), implantation (ESR1), infertility and spermatid differentiation. Our findings suggest that polycystic ovarian syndrome may lead to later age at first birth, linking with infertility. Late age at first birth is associated with parental longevity and reduced incidence of type 2 diabetes and cardiovascular disease. Higher childhood socioeconomic circumstances and those in the highest polygenic score decile (90%+) experience markedly later reproductive onset. Results are relevant for improving teenage and late-life health, understanding longevity and guiding experimentation into mechanisms of infertility.

Possible involvement of crosstalk between endometrial cells and mast cells in the development of endometriosis via CCL8/CCR1

BACKGROUND

The density and the activity of mast cells are associated with endometriosis. However, the role of mast cells on the pathogenesis of endometriosis remains unclear. Our study aims to investigate whether endometrial cells interact with mast cells and the involvement of their crosstalk in the development of endometriosis.

METHODS

The transwell assay was applied to investigate the effect of mast cells on the migratory ability of human primary endometrial cells. Mast cells were cocultured with endometrial epithelial and stromal cells respectively and total RNAs were isolated and subjected to mRNA sequencing. Next, the transwell assay, CCK-8, and tube formation were applied to study the role of CCL8 on the endometrial and endothelial cells in vitro. The mouse model was also established to confirm the role of CCL8 in the development and angiogenesis of endometriosis.

RESULTS

CCL8 was up-regulated in mast cells when cocultured with endometrial cells. CCL8 was highly expressed in the ectopic endometrium and the serum of patients with endometriosis. CCL8 promoted the migratory ability of endometrial epithelial and stromal cells and increased the proliferation, migration, and tube formation of endothelial cells. CCR1, the receptor of CCL8, was over-expressed in the ectopic endometrium and colocalized with blood vessels in ovarian endometriomas. The inhibition of CCR1 suppressed the development and angiogenesis of endometriosis in vivo.

CONCLUSION

The crosstalk between endometrial cells and mast cells in the development of endometriosis via CCL8/CCR1 was demonstrated, thereby providing a new treatment strategy for endometriosis.

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.

Premature Immunosenescence Impairs Immune Surveillance Allowing the Endometriotic Stem Cell to Migrate: The Cytokine Profile as a Common Denominator

While endometriosis, one of the most common reasons for infertility, remains a multifactorial condition and its exact cause highly speculative, there are data pointing to novel pathways of disease initiation which involve a stem cell and its ability to migrate and implant after it differentiates into an endometriotic stem cell. Thus, the mechanisms conferring immune surveillance, which would also normally expel the mesenchymal endometriotic cell, impairing its migration and implantation, appear to be negatively influenced by a state of endometriotic premature immunosenescence. This interplay between the two immunological mechanisms and endometriosis is influenced by a number of common factors having an active role in the host's protection process that inhibits harmful diseases and maintains cellular homeostasis. It appears more than coincidental that production/inhibition of IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-15, IL-18, TNF-α, VEGF, ICAM-1, and the number of Tolllike receptors is the same in immunosenescent states and in conditions with reduced immune surveillance, while the same variations are recorded in endometriotic patients. It is probable that these are common to all process signals, guide the endometriotic stem cell and dictate its fate according to the stochastic, transdifferentiation (plasticity) or deterministic model to become capable of migration and tissue invasion. It is currently unknown whether the pathway taken by the hemopoietic stem cell to become endometriotic represents a normal or aberrant route of development. This prompts research into its isolation and in vitro study of its behavior in order to reveal its potential function and role in endometriosis. (Journal of Endometriosis 2010; 2: 7–18)

The crosstalk between endometrial stromal cells and macrophages impairs cytotoxicity of NK cells in endometriosis by secreting IL-10 and TGF-β

The dysfunction of NK cells in women with endometriosis (EMS) contributes to the immune escape of menstrual endometrial fragments refluxed into the peritoneal cavity. The reciprocal communications between endometrial stromal cells (ESCs) and lymphocytes facilitate the development of EMS. However, the mechanism of these communications on cytotoxicity of natural killer (NK) cells in endometriotic milieus is still largely unknown. To imitate the local immune microenvironment, the co-culture systems of ESCs from patients with EMS and monocyte-derived macrophages or of ESCs, macrophages and NK cells were constructed. The cytokine levels in the co-culture unit were evaluated by ELISA. The expression of functional molecules in NK cells was detected by flow cytometry (FCM). The NK cell behaviors in vitro were analyzed by cell counting kit-8 and cytotoxic activation assays. After incubation with ESCs and macrophages, the expression of CD16, NKG2D, perforin and IFN-γ, viability and cytotoxicity of NK cells were significantly downregulated. The secretion of interleukin (IL)-1β, IL-10 and transforming growth factor (TGF)-β in the co-culture system of ESCs and macrophages was increased. Exposure with anti-IL-10 receptor β neutralizing antibody (αhIL-10Rβ) or αTGF-β could partly reverse these effects of ESCs and macrophages on NK cells in vitro These results suggest that the interaction between macrophages and ESCs downregulates cytotoxicity of NK cells possibly by stimulating the secretion of IL-10 and TGF-β, and may further trigger the immune escape of ectopic fragments and promote the occurrence and the development of EMS.

Molecular network analysis of endometriosis reveals a role for c-Jun-regulated macrophage activation

Clinical management of endometriosis is limited by the complex relationship between symptom severity, heterogeneous surgical presentation, and variability in clinical outcomes. As a complement to visual classification schemes, molecular profiles of disease activity may improve risk stratification to better inform treatment decisions and identify new approaches to targeted treatment. We use a network analysis of information flow within and between inflammatory cells to discern consensus behaviors characterizing patient subpopulations. Unsupervised multivariate analysis of cytokine profiles quantified by multiplex immunoassays identified a subset of patients with a shared "consensus signature" of 13 elevated cytokines that was associated with common clinical features of endometriosis, but was not observed among patient subpopulations defined by morphologic presentation alone. Enrichment analysis of consensus markers reinforced the primacy of peritoneal macrophage infiltration and activation, which was demonstrably elevated in ex vivo cultures. Although familiar targets of the nuclear factor κB family emerged among overrepresented transcriptional binding sites for consensus markers, our analysis provides evidence for an unexpected contribution from c-Jun, c-Fos, and AP-1 effectors of mitogen-associated kinase signaling. Their crucial involvement in propagation of macrophage-driven inflammatory networks was confirmed via targeted inhibition of upstream kinases. Collectively, these analyses suggest a clinically relevant inflammatory network that may serve as an objective measure for guiding treatment decisions for endometriosis management, and in the future may provide a mechanistic endpoint for assessing efficacy of new agents aimed at curtailing inflammatory mechanisms that drive disease progression.

Retinoic acid suppresses growth of lesions, inhibits peritoneal cytokine secretion, and promotes macrophage differentiation in an immunocompetent mouse model of endometriosis

OBJECTIVE

To determine the effects of all-trans-retinoic acid (RA) on establishment and growth of endometrial lesions, peritoneal interleukin-6 (IL-6) and macrophage chemotactic factor-1 (MCP-1) concentrations, and CD38, CD11b, and F4/80 expression on peritoneal macrophages in an immunocompetent mouse model of endometriosis.

DESIGN

Experimental transplantation study using mice.

SETTING

Academic medical center.

ANIMAL(S)

C57BL/6 recipient mice and syngeneic green fluorescent protein transgenic (GFP+) mice.

INTERVENTION(S)

Recipient mice were inoculated with GFP+ minced uterine tissue to induce endometriosis and treated with RA (400 nmol/day) or vehicle for 17 days (3 days before to 14 days after tissue injection).

MAIN OUTCOME MEASURE(S)

Total number of GFP+ implants in recipient mice, number of implants showing visible blood vessels, total volume of established lesions per mouse, concentrations of IL-6 and MCP-1 in peritoneal fluid, and expression of CD11b, F4/80, and CD38 on peritoneal macrophages.

RESULT(S)

Retinoic acid treatment for 17 days reduced the number of implants versus controls and decreased the frequency of lesions with vessels. Peritoneal washings in RA-treated animals had lower concentrations of IL-6 and MCP-1 than controls 3 days after endometrial inoculation and lower levels of IL-6 on day 14 after inoculation. Concomitant with these effects on day 14, CD38, CD11b, and F4/80 were higher on macrophages from RA-treated mice versus controls.

CONCLUSION(S)

The development of endometriotic implants is inhibited by RA. This effect may be caused, at least in part, by reduced IL-6 and MCP-1 production and enhanced differentiation of peritoneal macrophages.

Immune interactions in endometriosis

Endometriosis is a common, complex gynecologic disorder characterized by the presence of endometrial glands and stroma at extrauterine (ectopic) sites. In women who develop this disease, alterations in specific biological processes involving both the endocrine and immune systems have been observed, which may explain the survival and growth of displaced endometrial tissue in affected women. In the past decade, a considerable amount of research has implicated a role for alterations in progesterone action at both eutopic and ectopic sites of endometrial growth which may contribute to the excessive inflammation associated with progression of endometriosis; however, it remains unclear whether these anomalies induce the condition or are simply a consequence of the disease process. In this article, we summarize current knowledge of alterations within the immune system of endometriosis patients and discuss how endometrial cells from women with this disease not only have the capacity to escape immunosurveillance, but also use inflammatory mechanisms to promote their growth within the peritoneal cavity. Finally, we discuss evidence that exposure to an environmental endocrine disruptor, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin, can mediate the development of an endometrial phenotype that exhibits both reduced progesterone responsiveness and hypersensitivity to proinflammatory stimuli mimicking the endometriosis phenotype. Future studies in women with endometriosis should consider whether a heightened inflammatory response within the peritoneal microenvironment contributes to the development and persistence of this disease.

Endometriosis: the role of neuroangiogenesis

Endometriosis is a common cause of pelvic pain and infertility, affecting ∼10% of reproductive-age women. Annual costs for medical and surgical care in the United States exceed $20 billion. The disorder is characterized by implants of endometrial tissue outside the uterine cavity. Endometriotic lesions induce a state of chronic peritoneal inflammation, accompanied by elevated prostaglandin, cytokine, and growth factor concentrations. The current therapy is surgical ablation of ectopic implants and hormones that block the hypothalamic-pituitary-ovarian axis, but these approaches are expensive, carry perioperative risks, or have unpleasant side effects of hypoestrogenism. Recent evidence indicates that ectopic endometriotic implants recruit their own unique neural and vascular supplies through neuroangiogenesis. It is believed that these nascent nerve fibers in endometriosis implants influence dorsal root neurons within the central nervous system, increasing pain perception in patients. We consider the mechanisms and therapeutic implications of neuroangiogenesis in these lesions and propose potential treatments for the control or elimination of endometriosis-associated pain.

Cytokine and chemokine expression in a rat endometriosis is similar to that in human endometriosis

The pathogenesis of endometriosis, a gynecologic disorder associated with infertility, appears to involve immune responses. However, the details involved have not been clarified. In this study, we analyzed expression levels of interleukin (IL)-6, IL-10, monocyte chemoattractant protein-1, eosinophil chemotactic protein, macrophage inflammatory protein-1alpha, and regulated on activation normal T cell expressed and secreted (RANTES) and CC chemokine receptor 1 in endometriotic lesions in a rat model in which endometrium is autotransplanted onto peritoneal tissue and found that they were remarkably increased, while those of IL-2, IL-4, and interferon-gamma were not. These results were obtained in a rat model induced by autologous, not allogeneic, transplantation of endometrial epithelium to the peritoneum. Expression of these factors is consistent with that of endometriosis in humans. Therefore, this model may be useful in the investigation of the pathogenesis and treatment of endometriosis.

Cognate chemokine receptor 1 messenger ribonucleic acid expression in peripheral blood as a diagnostic test for endometriosis

We investigated the expression of the cognate chemokine receptor 1 (CCR1) messenger ribonucleic acid, a G-protein-coupled cognate chemokine receptor with high affinity for RANTES (Regulated upon Activation, Normal T cells Expressed and Secreted), in peripheral blood leukocytes of women with and without endometriosis, and its potential use as a diagnostic test for endometriosis. Because patients with an earlier diagnosis of this disease have a better treatment outcome and a reduced recurrence rate, CCR1 mRNA measurement in the peripheral blood of patients with suspected endometriosis might give us a new perspective in diagnosing and treating this disease earlier and better.

Is Endometriosis Associated with Systemic Subclinical Inflammation?

Endometriosis is a pelvic inflammatory process with altered function of immune-related cells and increased number of activated macrophages in the peritoneal environment that secrete various local products, such as growth factors and cytokines. The elevation of cytokines and other factors in the peritoneal fluid is accompanied by the elevation of similar factors, such as CRP, SAA, TNF-alpha, MCP-1, IL-6, IL-8 and CCR1, in the peripheral blood of patients with endometriosis. CD44+ and CD14+ monocytes are significantly increased, while CD3+ T lymphocytes and CD20+ B lymphocytes show modest, but significant decrease in peripheral blood of women with endometriosis. This indicates that endometriosis could be viewed as a local disease with systemic subclinical manifestations. This review provides an overview of data on the changes of various factors in peripheral blood and their potential use as diagnostic tools in patients with endometriosis.

Ten estrogen-related polymorphisms and endometriosis: a study of multiple gene-gene interactions

OBJECTIVE

Genetic as well as hormonal factors are known to influence the development and clinical course of endometriosis. We aimed to investigate the association among 10 single nucleotide polymorphisms (SNPs) involved in the estrogen metabolism and endometriosis and to develop a multiple genetic model.

METHODS

In a case-control study, we investigated the genotype frequencies of 10 estrogen metabolizing SNPs in 32 patients with endometriosis and 790 healthy controls using sequencing-on-chip-technology with solid-phase polymerase chain reaction on oligonucleotide microarrays: catechol-O-methyltransferase, Val158Met G->A, 17-beta-hydroxysteroid dehydrogenase type 1 (HSD17), vlV A->C, cytochrome P450 (CYP), 17 A2 allele T->C, CYP1A1 MspI RFLP T->C, CYP1A1 Ile462Val A->G, CYP19 Arg264Cys C->T, CYP19 C1558T C->T, CYP 1B1 Leu432Val, CYP1B1 Asn453Ser, and estrogen receptor alpha IVS1 -401>C. Associations and 2-way interaction models between SNPs were calculated by stepwise logistic regression models.

RESULTS

In a univariate model, HSD17 vlV A->C was associated with a significantly increased risk of endometriosis (P = .004; odds ratio 3.9, 95% confidence interval 1.6-9.8). When all 2-way interactions of investigated SNPs were ascertained, no significant interactions among SNPs were observed. In a multivariate model, HSD17 vlV A->C was also significantly associated with endometriosis (P = .002).

CONCLUSION

We present data on multiple SNPs in patients with endometriosis indicating an association between HSD17 gene variation and the disease. Although not able to demonstrate interaction models of SNPs, we provide evidence of HSD17 vlV A->C as a low penetrance genetic marker of endometriosis.

LEVEL OF EVIDENCE

II-2.