Peritoneal fluid from endometriosis patients switches differentiation of monocytes from dendritic cells to macrophages

Causal association of immune cells and endometriosis: a Mendelian randomization study

Objective

To investigate the causal effect of immune cells on endometriosis (EMS), we performed a Mendelian randomization analysis.

Methods

Mendelian randomization (MR) uses genetic variants as instrumental variables to investigate the causal effects of exposures on outcomes in observational data. In this study, we conducted a thorough two-sample MR analysis to investigate the causal relationship between 731 immune cells and endometriosis. We used complementary Mendelian randomization (MR) methods, including weighted median estimator (WME) and inverse variance weighted (IVW), and performed sensitivity analyses to assess the robustness of our results.

Results

Four immune phenotypes have been found to be significantly associated with the risk of developing EMS: B cell %lymphocyte (WME: OR: 1.074, p = 0.027 and IVW: OR: 1.058, p = 0.008), CD14 on Mo MDSC (WME: OR: 1.056, p =0.021 and IVW: OR: 1.047, p = 0.021), CD14+ CD16- monocyte %monocyte (WME: OR: 0.947, p = 0.024 and IVW: OR: 0.958, p = 0.011), CD25 on unsw mem (WME: OR: 1.055, p = 0.030 and IVW: OR: 1.048, p = 0.003). Sensitivity analyses confirmed the main findings, demonstrating consistency across analyses.

Conclusions

Our MR analysis provides compelling evidence for a direct causal link between immune cells and EMS, thereby advancing our understanding of the disease. It also provides new avenues and opportunities for the development of immunomodulatory therapeutic strategies in the future.

Unraveling immunotherapeutic targets for endometriosis: a transcriptomic and single-cell analysis

Background

Endometriosis (EMs), a common gynecological disorder, adversely affects the quality of life of females. The pathogenesis of EMs has not been elucidated and the diagnostic methods for EMs have limitations. This study aimed to identify potential molecular biomarkers for the diagnosis and treatment of EMs.

Methods

Differential gene expression (DEG) and functional enrichment analyses were performed using the R language. WGCNA, Random Forest, SVM-REF and LASSO methods were used to identify core immune genes. The CIBERSORT algorithm was then used to analyse the differences in immune cell infiltration and to explore the correlation between immune cells and core genes. In addition, the extent of immune cell infiltration and the expression of immune core genes were investigated using single-cell RNA (scRNA) sequencing data. Finally, we performed molecular docking of three core genes with dienogest and goserelin to screen for potential drug targets.

Results

DEGs enriched in immune response, angiogenesis and estrogen processes. CXCL12, ROBO3 and SCG2 were identified as core immune genes. RT-PCR confirmed that the expression of CXCL12 and SCG2 was significantly upregulated in 12Z cells compared to hESCs cells. ROC curves showed high diagnostic value for these genes. Abnormal immune cell distribution, particularly increased macrophages, was observed in endometriosis. CXCL12, ROBO3 and SCG2 correlated with immune cell levels. Molecular docking suggested their potential as drug targets.

Conclusion

This study investigated the correlation between EMs and the immune system and identified potential immune-related biomarkers. These findings provided valuable insights for developing clinically relevant diagnostic and therapeutic strategies for EMs.

Understanding endometriosis from an immunomicroenvironmental perspective

ABSTRACT

Endometriosis, a heterogeneous, inflammatory, and estrogen-dependent gynecological disease defined by the presence and growth of endometrial tissues outside the lining of the uterus, affects approximately 5-10% of reproductive-age women, causing chronic pelvic pain and reduced fertility. Although the etiology of endometriosis is still elusive, emerging evidence supports the idea that immune dysregulation can promote the survival and growth of retrograde endometrial debris. Peritoneal macrophages and natural killer (NK) cells exhibit deficient cytotoxicity in the endometriotic microenvironment, leading to inefficient eradication of refluxed endometrial fragments. In addition, the imbalance of T-cell subtypes results in aberrant cytokine production and chronic inflammation, which contribute to endometriosis development. Although it remains uncertain whether immune dysregulation represents an initial cause or merely a secondary enhancer of endometriosis, therapies targeting altered immune pathways exhibit satisfactory effects in preventing disease onset and progression. Here, we summarize the phenotypic and functional alterations of immune cells in the endometriotic microenvironment, focusing on their interactions with microbiota and endocrine and nervous systems, and how these interactions contribute to the etiology and symptomology of endometriosis.

The role of dendritic cells in endometriosis: A systematic review

Endometriosis (EDT), a common estrogen-dependent inflammatory disorder, is characterized by endometrial-like tissue outside the uterus. While its pathogenesis is poorly understood, it is supposed that the immune system plays a role in its pathophysiology, and increased number of immune cells and changes in both cell-mediated and humoral immunity have been described. Dendritic cells (DCs) are antigen-presenting cells (APC) of the immune system that recognize, capture, and process complex antigens and present them to T cells, conferring them a unique ability as mediators between the innate and adaptive immune systems. This systematic review aims to enlighten possible disturbances (systemically and locally) of DCs in the development and progression of endometriosis. A search using the strategy: ("dendritic cells" AND "immunology" AND "endometriosis") in databases resulted in 490 citations; after applying inclusion and exclusion criteria, a total of 13 studies were assessed. The evaluated studies demonstrated that DCs are susceptible to pro-endometriotic changes which could inhibit immature DCs (imDCs) from their maturation and induce imDCs into a macrophage phenotype. In addition, the growth and vascularization of endometriosis requires the presence of endogenous DC, which infiltrate endometriotic lesions and enhance endothelial cell migration by secreting proangiogenic factors. Whereas DC maturation suppresses this response, imDC actively promote angiogenesis and growth, leading to a switch in their immunologic role from presenting antigens to support angiogenesis and EDT progression.

Mesenchymal Stromal Cells Isolated from Ectopic but Not Eutopic Endometrium Display Pronounced Immunomodulatory Activity In Vitro

A comparative analysis of the cell surface markers and immunological properties of cell cultures originating from normal endometrium and endometrioid heterotopias of women with extragenital endometriosis was carried out. Both types of cell cultures expressed surface molecules typical of mesenchymal stromal cells and did not express hematopoietic and epithelial markers. Despite similar phenotype, the mesenchymal stromal cells derived from the two sources had different immunomodulation capacities: the cells of endometrioid heterotopias but not eutopic endometrium could suppress dendritic cell differentiation from monocytes as well as lymphocyte proliferation in allogeneic co-cultures. A comparative multiplex analysis of the secretomes revealed a significant increase in the secretion of pro-inflammatory mediators, including IL6, IFN-γ, and several chemokines associated with inflammation by the stromal cells of ectopic lesions. The results demonstrate that the stromal cells of endometrioid heterotopias display enhanced pro-inflammatory and immunosuppressive activities, which most likely impact the pathogenesis and progression of the disease.

Role of IL-6 in dendritic cell functions

Dendritic cells (DCs) are efficient antigen-presenting cells that serve as a link between the innate and adaptive immune systems. These cells are broadly involved in cellular and humoral immune responses by presenting antigens to initiate T cell reactions, cytokine and chemokine secretion, T cell differentiation and expansion, B cell activation and regulation, and the mediation of immune tolerance. The functions of DCs depend on their activation status, which is defined by the stages of maturation, phenotype differentiation, and migration ability, among other factors. IL-6 is a soluble mediator mainly produced by a variety of immune cells, including DCs, that exerts pleiotropic effects on immune and inflammatory responses through interaction with specific receptors expressed on the surface of target cells. Here, we review the role of IL-6, when generated in an inflammatory context or as derived from DCs, in modulating the biologic function and activation status of DCs and emphasize the importance of searching for novel strategies to target the IL-6/IL-6 signaling pathway as a means to diminish the inflammatory activity of DCs in immune response or to prime the immunogenic activity of DCs in immunosuppressive conditions.

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.

Morphologic Features Suggestive of Endometriosis in Nondiagnostic Peritoneal Biopsies

Endometriosis is a common disorder that causes significant morbidity from dysmenorrhea, pelvic pain, and subfertility. Establishment of a definitive diagnosis has important therapeutic implications; however, only approximately 50% of biopsies of laparoscopically suspicious areas provide a diagnosis of endometriosis. Histologic criteria for diagnosis require the presence of endometrial glands or endometrial-type stroma. We hypothesize that other frequently present, but nondiagnostic, histologic features of endometriosis suggest its presence in patients with nondiagnostic peritoneal biopsies. We performed a retrospective clinicopathologic study of morphologic and immunohistochemical features that may improve the histologic diagnosis of endometriosis on laparoscopic peritoneal biopsies. We compared diagnostic (n=88) and nondiagnostic (n=54) peritoneal biopsies from pathologically confirmed endometriosis cases with negative peritoneal biopsies (n=84) from early-stage gynecologic cancer cases. Statistical analysis utilized the Fisher exact test. Multiple morphologic features were significantly increased in nondiagnostic biopsies from patients with endometriosis in comparison with those from negative controls, including foamy macrophages (P=0.0001) and submesothelial stromal clusters (SSCs) (P=0.0008). SSCs ranged from subtle aggregates of spindle cells to nodules of whorled spindle cells with small vessels and extravasated red blood cells resembling stromal endometriosis. Immunohistochemical studies confirmed that ER and CD10-positive SSCs were present in a greater proportion of both nondiagnostic and diagnostic peritoneal biopsies and at a greater number of lesions per biopsy. The overall histologic detection rate of peritoneal biopsies for endometriosis was 62.0%, and inclusion of SSCs with or without foamy macrophages in the diagnostic criteria appreciably increased this rate to between 72.5% and 76.8%. We describe SSCs, which appear to be an early or less developed form of stromal endometriosis, and, when included in the diagnostic criteria, improve the histologic detection rate of endometriosis in peritoneal biopsies.

Pathophysiology and Immune Dysfunction in Endometriosis

Endometriosis is an estrogen-dependent, chronic, proinflammatory disease prevalent in 10% of women of reproductive age worldwide. Characterized by the growth of endometrium-like tissue in aberrant locations outside of the uterus, it is responsible for symptoms including chronic pelvic pain, dysmenorrhea, and subfertility that degrade quality of life of women significantly. In Canada, direct and indirect economic cost of endometriosis amounts to 1.8 billion dollars, and this is elevated to 20 billion dollars in the United States. Despite decades of research, the etiology and pathophysiology of endometriosis still remain to be elucidated. This review aims to bring together the current understanding regarding the pathogenesis of endometriosis with specific focus on mechanisms behind vascularization of the lesions and the contribution of immune factors in facilitating lesion establishment and development. The role of hormones, immune cells, and cytokine signaling is highlighted, in addition to discussing the current pharmaceutical options available for management of pain symptoms in women with endometriosis.

Dendritic cells attenuate the early establishment of endometriosis-like lesions in a murine model

Complex interplay of innate and adaptive immune cells has been implicated in the establishment, maintenance, and progression of endometriosis. Defining the identity, activation state, and functional role of immune cells during lesion establishment will provide invaluable insight into the underlying mechanisms of disease. This study utilized a transgenic mouse model with conditional dendritic cell (DC) depletion (diphtheria toxin-treated B6.FVB-Itgax-hDTR-EGFP(tg)) and multiparametric flow cytometry to examine immune cell composition and activation state and to assess the functional role of DCs in endometriosis-like lesions. T cells and DCs were increased in lesions compared to native uteri and control splenocytes and demonstrated an activated phenotype (P < .05). Lesions in DC-depleted hosts demonstrated greater size (P < .001) and reduced expression of T-cell activation marker CD69 compared to controls (P < .05). Collectively, these results suggest that activated DCs within lesions activate T cells and result in the impairment of early lesion establishment.

Dendritic cell populations in the eutopic and ectopic endometrium of women with endometriosis

BACKGROUND

Immune alterations may be involved in the pathogenesis and progression of endometriosis. Dendritic cells (DCs) are potent antigen presenting cells that are highly involved in the initiation of the immune response. The aim of this study was to investigate DC populations in the eutopic and ectopic endometrium of women with endometriosis compared with controls.

METHODS

Hysterectomy samples were obtained from premenopausal women with (n = 33) and without (n = 28) endometriosis. In addition, paired peritoneal endometriotic lesions and uterine curettings were collected from 32 women with endometriosis. Specimen sections were stained immunohistochemically using antibodies for monoclonal mouse antibodies directed against human CD1a and CD83, which are specific for immature and mature DCs, respectively.

RESULTS

The mean density of endometrial CD1a+ DCs in the basal layer was significantly increased in women with endometriosis compared with controls during the proliferative phase only (P = 0.001). There was a highly significant decrease in the density of endometrial CD83+ DCs in women with endometriosis compared with controls in both layers of the endometrium across all phases of the menstrual cycle (P = 0.001). The density of CD1a+ DCs was significantly increased in peritoneal endometriotic lesions (P = 0.003) and in the surrounding peritoneum (P = 0.001) compared with paired uterine curettings and peritoneum distant from the lesion.

CONCLUSIONS

Both CD1a+ and CD83+ DC populations were altered in the eutopic and ectopic endometrium of women with endometriosis compared with controls. Alterations in these cells, which play a crucial role in the coordination of the immune response, may be involved in pain generation and the pathogenesis of endometriosis.

ERB-041, a selective ER beta agonist, inhibits iNOS production in LPS-activated peritoneal macrophages of endometriosis via suppression of NF-kappaB activation

OBJECTIVE

The aim of the present study was to assess the anti-inflammatory effects of selective ER beta (ER beta) agonist on lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) production in peritoneal macrophages (PMs) of endometriosis (EMS).

METHODS

ER alpha (ER alpha) and ER beta expressions in PMs were analyzed by RT-PCR and immunoblot. The PMs of endometriosis were exposed to increasing concentrations of ER beta agonist ERB-041 over a period from 0.5 to 8h before stimulation with LPS and the levels of iNOS protein were evaluated by immunoblot. Subsequently, the PMs were pretreated with vehicle, ERB-041 or ER alpha agonist PPT before exposing to LPS. iNOS expression, p65 protein and active extracellular signal-regulated kinases (ERKs) level accumulated in the nuclear were detected by immunoblot. For experiment investigating the role of ERKs in LPS-induced iNOS expression, the PMs were pretreated with U0126, a specific ERK inhibitor, for 60 min before LPS treatment and iNOS expression was detected by immunoblot.

RESULTS

The PMs of EMS expressed ER beta to a greater extent compared with normal women. Pretreatment the PMs with ERB-041 resulted in a significant inhibition of LPS-induced iNOS expression and NF-kappaB activation by preventing its nuclear translocation. The ERKs pathway was involved in the LPS-induced iNOS production and was not repressed by the activation of ERs.

CONCLUSION

The inhibitory effect of ER beta agonist on LPS-induced iNOS production in PMs of EMS is likely mediated via repressing of nuclear factor-kappa B (NF-kappaB) but not ERKs signaling pathways.

NF-kappaB decoy oligonucleotides suppress RANTES expression and monocyte chemotactic activity via NF-kappaB inactivation in stromal cells of ectopic endometrium

BACKGROUND

The nuclear factor kappa B (NF-kappaB) pathway is a critical mediator of regulated on activation, normal T cell expressed and secreted (RANTES) gene regulation and therefore represents a potential target for therapy of endometriosis-associated symptoms.

OBJECTIVE

The objective of this study was to investigate the effect of NF-kappaB decoy oligonucleotides (ODNs) on NF-kappaB activation, RANTES expression, and monocyte chemotactic activity in ectopic endometrial stromal cells in vitro.

METHODS

A specific sandwich enzyme-linked immunosorbent assay (ELISA) was used to quantify RANTES expression in ectopic and normal endometrial stromal cells stimulated by interleukin (IL)-1beta. Four hours after transfection of NF-kappaB decoy ODNs, 10 ng/ml IL-1beta was added to induce the ectopic endometrial stromal cells to secrete RANTES. The NF-kappaB activation, RANTES expression, and monocyte chemotactic activity in ectopic endometrial stromal cells were respectively evaluated by electrophoretic mobility shift assay, ELISA, and Boyden chambers.

RESULTS

IL-1beta induced significantly higher levels (P < 0.05) of RANTES expression in a time-dependent manner in ectopic endometrial stromal cells compared with IL-1beta-untreated ectopic and normal endometrial stromal cells. The RANTES accounts for the majority (68%) of the monocyte chemotactic activity in conditioned media of ectopic endometrial stromal cells. In vitro transfection of NF-kappaB decoy ODNs dramatically decreased (P < 0.05) the NF-kappaB activation, RANTES expression, and monocyte chemotactic activity in IL-1beta-induced ectopic endometrial stromal cells.

CONCLUSIONS

NF-kappaB decoy ODNs may exert anti-inflammatory effects in ectopic endometrial stromal cells via the suppression of NF-kappaB activation, RANTES expression, and monocyte chemotactic activity.