Interleukin 6 secretion from alternatively activated macrophages promotes the migration of endometriotic epithelial cells

Emerging bioengineering breakthroughs in precision diagnosis and therapy for endometriosis and adenomyosis

Endometriosis and adenomyosis are debilitating gynecological conditions that severely affect the quality of life of women. Traditional diagnostic and treatment methods, including laparoscopic surgery and hormonal therapy, face significant limitations such as incomplete lesion detection, high recurrence rates, and adverse side effects. Emerging bioengineering technologies offer promising solutions for precise diagnosis and therapy of these diseases. Advances in biomarker detection through electrochemical immunosensors, including specific molecular markers like cytokines and growth factors, have improved their early diagnosis. Innovative imaging techniques, such as near-infrared fluorescence imaging, magnetic resonance imaging, and photoacoustic imaging, enhance lesion visualization and surgical precision. In therapeutic applications, bioengineered drug delivery systems enable targeted therapy by modifying drug carriers with ligands targeting highly expressed receptors in endometriotic lesions. Such strategies could improve drug accumulation at target sites and reduce damage to healthy tissues. Integrating external energy (including lasers, focused ultrasound, and magnetic fields) with nanoplatforms offers key benefits for treating endometriosis and adenomyosis, allowing precise delivery of energy-responsive molecules to lesions and minimizing damage to healthy tissues. Additionally, novel approaches, such as immunotherapy, gene therapy, ferroptosis induction, and synthetic lethal activation, offer new avenues for effective treatment of endometriosis and adenomyosis. Significantly, this paper discusses the advantages of precision diagnosis and treatment of endometriosis in preserving the fertility of women of reproductive age. This review highlights the potential of bioengineering breakthroughs to transform the diagnosis and management of endometriosis and adenomyosis, emphasizing their role in advancing precision medicine and improving women's health.

The long road of drug development for endometriosis - Pains, gains, and hopes

Endometriosis, defined by the growth of endometrial tissues outside of the uterine cavity, is a global health burden for ∼200 million women. Patients with endometriosis usually present with chronic pain and are often diagnosed with infertility. The pathogenesis of endometriosis is still an open question; however, tissue stemness and immunological and genetic factors have been extensively discussed in the establishment of endometriotic lesions. Current treatments for endometriosis can be categorized into pharmacological management of hormone levels and surgical removal of the lesions. Both approaches have limited efficacy, with recurrences often encountered; thus, there is no complete cure for the disease or its symptoms. We review the current knowledge of the etiology of endometriosis and summarize the advancement of pharmacological management of endometriosis. We also discuss our efforts in applying DNA-encoded chemistry technology (DEC-Tec) to identify bioactive molecules for the treatment of endometriosis, offering new avenues for developing non-hormonal treatment options for those patients who seek spontaneous pregnancies.

TET3-overexpressing macrophages promote endometriosis

Endometriosis is a debilitating, chronic inflammatory disease affecting approximately 10% of reproductive-age women worldwide with no cure. While macrophages have been intrinsically linked to the pathophysiology of endometriosis, targeting them therapeutically has been extremely challenging due to their high heterogeneity and because these disease-associated macrophages (DAMs) can be either pathogenic or protective. Here, we report identification of pathogenic macrophages characterized by TET3 overexpression in human endometriosis lesions. We show that factors from the disease microenvironment upregulated TET3 expression, transforming macrophages into pathogenic DAMs. TET3 overexpression stimulated proinflammatory cytokine production via a feedback mechanism involving inhibition of let-7 miRNA expression. Remarkably, these cells relied on TET3 overexpression for survival and hence were vulnerable to TET3 knockdown. We demonstrated that Bobcat339, a synthetic cytosine derivative, triggered TET3 degradation in both human and mouse macrophages. This degradation was dependent on a von Hippel-Lindau (VHL) E3 ubiquitin ligase whose expression was also upregulated in TET3-overexpressing macrophages. Furthermore, depleting TET3-overexpressing macrophages either through myeloid-specific Tet3 ablation or using Bobcat339 strongly inhibited endometriosis progression in mice. Our results defined TET3-overexpressing macrophages as key pathogenic contributors to and attractive therapeutic targets for endometriosis. Our findings may also be applicable to other chronic inflammatory diseases where DAMs have important roles.

Targeting TET3 in macrophages provides a concept strategy for the treatment of endometriosis

Endometriosis, characterized by the presence of endometrial-like tissue outside the uterus, is a condition associated with pain and infertility. In this issue of the JCI, Lv et al. illuminate the critical pathophysiological role of the ten-eleven translocation 3 (TET3) in endometriosis. TET3 expression levels were higher in macrophages of endometriotic lesions compared with control endometrial tissue, implicating TET3 as a contributing factor in the chronic inflammation that occurs in endometriosis. TGF-β1 and MCP1 are present in the peritoneal cavity of women with endometriosis, and macrophage exposure to these factors resulted in upregulation of TET3, thereby promoting their survival. Notably, Bobcat339, a selective TET inhibitor, induced apoptosis in these macrophages. Further, myeloid-specific TET3 loss reduced endometriosis in mice. RNA-Seq analysis following TET3 knockdown revealed alterations in cytokine signaling and cell-death pathways, underscoring the therapeutic potential of targeting TET3 in macrophages as a strategy for managing endometriosis.

Resveratrol and Its Natural Analogs Mitigate Immune Dysregulation and Oxidative Imbalance in the Endometriosis Niche Simulated in a Co-Culture System of Endometriotic Cells and Macrophages

Background: Inflammation and immune cell dysfunction are critical facilitators of endometriosis pathophysiology. Macrophages are renowned for stimulating lesion growth, vascularization, innervation, and pain generation. By combining macrophages and endometriotic cells, we determined if resveratrol and its natural analogs can target the immune dysregulation and oxidative imbalance in endometriosis. Methods: After treatment with compounds (5, 10, 25 µM), we evaluated the expression of key inflammatory and oxidative stress markers, cytokines release, and ROS production by applying q-PCR, ELISA, Cytometric Beads Array, and multiplexed fluorogenic staining and flow cytometry analysis with bioimaging. Results: The results showed that endometriosis-related macrophages treated with stilbenes have impaired expression of pro-inflammatory markers (IL6, IL8, IL1B, TNF, CCL2, CXCL10, PTGS2). The effect of resveratrol, pterostilbene, and piceatannol was observed, especially in reducing IL1B, CCL2, and CXCL10 genes up to 3.5-, 5-, and 7.7-fold at 25 µM, respectively. Also, with piceatannol or polydatin exposure, the IL-6 decrease was noticeable. This study reported an antioxidant effect by reducing ROS-positive cells from 96% to 48% by pterostilbene. Results from flow cytometry correlated with the transcript activation of detoxification enzymes (SOD, GPX). Conclusions: Prospects for potential therapy based on regulating the immune microenvironment and reducing the accumulation of free radicals with stilbenes application were described in the article.

Crimson clues: advancing endometriosis detection and management with novel blood biomarkers

Endometriosis is an inflammatory condition affecting approximately 10% of the female-born population. Despite its prevalence, the lack of noninvasive biomarkers has contributed to an established global diagnostic delay. The intricate pathophysiology of this enigmatic disease may leave signatures in the blood, which, when detected, can be used as noninvasive biomarkers. This review provides an update on how investigators are utilizing the established disease pathways and innovative methodologies, including genome-wide association studies, next-generation sequencing, and machine learning, to unravel the clues left in the blood to develop blood biomarkers. Many blood biomarkers show promise in the discovery phase, but because of a lack of standardized and robust methodologies, they rarely progress to the development stages. However, we are now seeing biomarkers being validated with high diagnostic accuracy and improvements in standardization protocols, providing promise for the future of endometriosis blood biomarkers.

Regulatory T cell adoptive transfer alters uterine immune populations, increasing a novel MHC-IIlow macrophage associated with healthy pregnancy

Intrauterine fetal demise (IUFD) - fetal loss after 20 weeks - affects 6 pregnancies per 1,000 live births in the United States, and the majority are of unknown etiology. Maternal systemic regulatory T cell (Treg) deficits have been implicated in fetal loss, but whether mucosal immune cells at the maternal-fetal interface contribute to fetal loss is under-explored. We hypothesized that the immune cell composition and function of the uterine mucosa would contribute to the pathogenesis of IUFD. To investigate local immune mechanisms of IUFD, we used the CBA mouse strain, which naturally has mid-late gestation fetal loss. We performed a Treg adoptive transfer and interrogated both pregnancy outcomes and the impact of systemic maternal Tregs on mucosal immune populations at the maternal-fetal interface. Treg transfer prevented fetal loss and increased an MHC-IIlow population of uterine macrophages. Single-cell RNA-sequencing was utilized to precisely evaluate the impact of systemic Tregs on uterine myeloid populations. A population of C1q+, Trem2+, MHC-IIlow uterine macrophages were increased in Treg-recipient mice. The transcriptional signature of this novel uterine macrophage subtype is enriched in multiple studies of human healthy decidual macrophages, suggesting a conserved role for these macrophages in preventing fetal loss.

How do pre-pregnancy endometrial macrophages contribute to pregnancy?

Macrophages are professional phagocytes with a wide distribution in all tissues throughout the body. Macrophages play a crucial role in homeostasis and numerous physiological processes beyond innate and adaptive immunity, including cellular debris removal, metabolic regulation, tissue repair, and tissue remodeling. Uterine macrophages are a heterogeneous and highly plastic subset of immune cells regulated by the local microenvironment and, in addition to their anti-inflammatory and anti-infective functions, support the establishment and maintenance of pregnancy. Comprehensive reviews have summarized the role of decidual macrophages during pregnancy. However, the distribution of macrophages in the endometrium prior to pregnancy, their functional remodeling, and the knock-on effects on subsequent pregnancies have not been elucidated. In this review, we focus on 1) how the phenotypes of endometrial macrophages and their interactions with other endometrial cells indicate or contribute to the subsequent pregnancy, 2) the adaptive switching of endometrial macrophages during the initial establishment of pregnancy, 3) and the pregnancy complications and pregnancy-related disorders associated with endometrial macrophages.

Inflammation-Related Molecules at the Maternal-Fetal Interface during Pregnancy and in Pathologically Altered Endometrium

The blastocyst expresses paternally derived alloantigens and induces inflammation during implantation. However, it is necessary for the onset of pregnancy. An abnormal response might result in a pathological course of pregnancy or pregnancy failure. On the other hand, a state of maternal immune tolerance is necessary to ensure the normal development of pregnancy by suppressing inflammatory processes. This article discusses recognized mechanisms and the significance of inflammatory processes for embryo implantation and pregnancy establishment. We would also like to present disorders involving excessive inflammatory response and their influence on events occurring during embryo implantation. The chain of correlation between the processes responsible for embryo implantation and the subsequent physiological course of pregnancy is complicated. Many of those interrelationships are still yet to be discovered. Undoubtedly, their recognition will give hope to infertile couples for the emergence of new treatments that will increase the chance of giving birth to a healthy child.

In vitro modeling of endometriosis and endometriotic microenvironment - Challenges and recent advances

Endometriosis is a chronic condition with high prevalence in reproductive age women, defined as the growth of endometrial tissue outside the uterine cavity, most commonly on the pelvic peritoneum. The ectopic endometrial lesions exist in a unique microenvironment created by the interaction of epithelial, stromal, endothelial, glandular, and immune cell components, dominated by inflammatory, angiogenic, and endocrine signals. Current research is directed at understanding the complex microenvironment of the lesions and its relationship with different endometriosis stages, phenotypes, and disease symptoms and at the development of novel diagnostic and therapeutic concepts that minimalize the undesirable side effects of current medical management. Recreating pathophysiological cellular and molecular mechanisms and identifying clinically relevant metrics to assess drug efficacy is a great challenge for the experimental disease models. This review summarizes the complete range of available in vitro experimental systems used in endometriotic studies, which reflect the multifactorial nature of the endometriotic lesion. The article discusses the simplistic in vitro models such as primary endometrial cells and endometriotic cell lines to heterogeneous 2D co-cultures, and recently more common, 3D systems based on self-organization and controlled assembly, both in microfluidic or bioprinting methodologies. Basic research models allow studying fundamental pathological mechanisms by which menstrual endometrium adheres, invades, and establishes lesions in ectopic sites. The advanced endometriosis experimental models address the critical challenges and unsolved problems and provide an approach to drug screening and medicine discovery by mimicking the complicated behaviors of the endometriotic lesion.

2-methylpyridine-1-ium-1-sulfonate modifies tumor-derived exosome mediated macrophage polarization: Relevance to the tumor microenvironment

The compound "2-methylpyridine-1-ium-1-sulfonate" (MPS) is the active constituent of Allium hirtifolium Boiss. bulbs with potent anti-angiogenic and anti-cancer activities. Tumor microenvironment (TME) plays a key role in tumor progression via tumor derived exosome (TEX) mediated polarization of M2 type tumor associated macrophages (TAMs). In this study, we explored direct and colorectal cancer (CRC) exosome-mediated impacts of MPS on macrophage polarization to find out whether MPS could modify TEX in favor of anti-tumor M1-like macrophage polarization. After MPS isolation and characterization, first its direct anti-cancer effects were evaluated on HT-29 cells. Then, TEX were isolated from untreated (C-TEX) and MPS-treated (MPS-TEX) HT-29 cells. THP-1 M0 macrophages were incubated with MPS, C-TEX and MPS-TEX. Macrophage polarization was evaluated by flow cytometry, ELISA and gene expression analysis of several M1- and M2-related markers. MPS induced apoptosis and cell cycle arrest and reduced the migration ability of HT-29 cells. C-TEX polarized M0 macrophages toward a mixed M1-/M2-like phenotype with a high predominance of M2-like cells. Macrophage treatment with MPS was associated with the induction of M1-like phenotype. Also, MPS was demonstrated to ameliorate TEX-mediated effects in favor of M1-like polarization. In conclusion, our study addresses for the first time, the potential capability of MPS in skewing macrophages toward an anti-cancer M1-like phenotype both directly and in a TEX-dependent manner. Thus, in addition to its direct anti-cancer effects, this compound could also modify TME in favor of tumor eradication via its direct and TEX-mediated effects on macrophage polarization as a novel anti-cancer mechanism.

Understanding the molecular mechanisms of macrophage polarization and metabolic reprogramming in endometriosis: A narrative review

Background

Endometriosis is an estrogen-dependent disease and causes pelvic pain and infertility. The limits of current pharmacotherapy in women who desire to become pregnant prompt the development of various targeted molecules for more effective treatment. A review article focused on the unique aspect of cellular metabolic reprogramming of endometriotic cells has been reported. The cellular metabolic pathways are reprogrammed to adapt to a variety of environmental stresses (e.g., nutrient starvation or glucose deprivation, hypoxic stress, excessive reactive oxygen species generation, and other environmental factors). This review aims to summarize macrophage polarization and metabolic reprogramming in endometriosis.

Methods

A literature search was performed between January 2000 and March 2022 in the PubMed and Google Scholar databases using a combination of specific terms.

Results

Macrophage cellular metabolism has a marked influence on its phenotype and function. Preclinical studies showed that metabolic conversion toward glycolysis or oxidative phosphorylation drives macrophage polarization to M1 or M2 phenotype, respectively. Such cellular metabolic rewiring can offer new therapeutic opportunities.

Conclusion

A better understanding of metabolic reprogramming biology in endometriosis-associated macrophages is essential in considering novel therapeutic approach for endometriosis. However, there are currently no detailed studies on therapeutic strategies targeting the cellular metabolic properties of endometriosis-associated macrophages.

Association of microbial dynamics with urinary estrogens and estrogen metabolites in patients with endometriosis

Endometriosis is an estrogen dependent gynecological disease associated with altered microbial phenotypes. The association among endogenous estrogen, estrogen metabolites, and microbial dynamics on disease pathogenesis has not been fully investigated. Here, we identified estrogen metabolites as well as microbial phenotypes in non-diseased patients (n = 9) and those with pathologically confirmed endometriosis (P-EOSIS, n = 20), on day of surgery (DOS) and ~1–3 weeks post-surgical intervention (PSI). Then, we examined the effects of surgical intervention with or without hormonal therapy (OCPs) on estrogen and microbial profiles of both study groups. For estrogen metabolism analysis, liquid chromatography/tandem mass spectrometry was used to quantify urinary estrogens. The microbiome data assessment was performed with Next generation sequencing to V4 region of 16S rRNA. Surgical intervention and hormonal therapy altered gastrointestinal (GI), urogenital (UG) microbiomes, urinary estrogen and estrogen metabolite levels in P-EOSIS. At DOS, 17β-estradiol was enhanced in P-EOSIS treated with OCPs. At PSI, 16-keto-17β-estradiol was increased in P-EOSIS not receiving OCPs while 2-hydroxyestradiol and 2-hydroxyestrone were decreased in P-EOSIS receiving OCPs. GI bacterial α-diversity was greater for controls and P-EOSIS that did not receive OCPs. P-EOSIS not utilizing OCPs exhibited a decrease in UG bacterial α-diversity and differences in dominant taxa, while P-EOSIS utilizing OCPs had an increase in UG bacterial α-diversity. P-EOSIS had a strong positive correlation between the GI/UG bacteria species and the concentrations of urinary estrogen and its metabolites. These results indicate an association between microbial dysbiosis and altered urinary estrogens in P-EOSIS, which may impact disease progression.

Circulating miRNAs Related to Epithelial-Mesenchymal Transitions (EMT) as the New Molecular Markers in Endometriosis

Endometriosis is a chronic gynecological disease defined by the presence of endometrial-like tissue found outside the uterus, most commonly in the peritoneal cavity. Endometriosis lesions are heterogenous but usually contain endometrial stromal cells and epithelial glands, immune cell infiltrates and are vascularized and innervated by nerves. The complex etiopathogenesis and heterogenity of the clinical symptoms, as well as the lack of a specific non-invasive diagnostic biomarkers, underline the need for more advanced diagnostic tools. Unfortunately, the contribution of environmental, hormonal and immunological factors in the disease etiology is insufficient, and the contribution of genetic/epigenetic factors is still fragmentary. Therefore, there is a need for more focused study on the molecular mechanisms of endometriosis and non-invasive diagnostic monitoring systems. MicroRNAs (miRNAs) demonstrate high stability and tissue specificity and play a significant role in modulating a range of molecular pathways, and hence may be suitable diagnostic biomarkers for the origin and development of endometriosis. Of these, the most frequently studied are those related to endometriosis, including those involved in epithelial–mesenchymal transition (EMT), whose expression is altered in plasma or endometriotic lesion biopsies; however, the results are ambiguous. Specific miRNAs expressed in endometriosis may serve as diagnostics markers with prognostic value, and they have been proposed as molecular targets for treatment. The aim of this review is to present selected miRNAs associated with EMT known to have experimentally confirmed significance, and discuss their utility as biomarkers in endometriosis.

M1 Macrophage-Derived Nanovesicles Repolarize M2 Macrophages for Inhibiting the Development of Endometriosis

Background

Endometriosis is a common nonmalignant gynecological disorder that affects 10–15% women of reproductive age and causes several symptoms that result in decreased quality of life and a huge social burden. In recent decades, extracellular vesicles (EVs) have gained attention as a potential therapeutic tool; however, the therapeutic effects of EVs against endometriosis have not been reported. Accordingly, in this study, we investigated the feasibility of nanovesicles (NVs) derived from M1 macrophages (M1NVs) in treating endometriosis.

Methods

M1NVs were prepared by serial extrusion. Co-culture assays were performed to investigate changes in tube formation and migration/invasion of eutopic endometrial stroma cells (ESCs) obtained from patients with endometriosis (EM-ESCs). A mouse model of endometriosis was established, and mice were treated with phosphate-buffered saline, M0NVs, or M1NVs to evaluate the efficacy and safety of M1NV for treating endometriosis.

Results

M1NVs directly or indirectly inhibited the migration and invasion of EM-ESCs and reduced tube formation. In the mouse model, M1NVs suppressed the development of endometriosis through reprogramming of M2 macrophages, without causing damage to the organs.

Conclusions

M1NVs inhibit the development of endometriosis directly, or through repolarizing macrophages from M2 to M1 phenotype. Hence, administration of M1NVs may represent a novel method for the treatment of endometriosis.

Identification and Exploration of Novel Macrophage M2-Related Biomarkers and Potential Therapeutic Agents in Endometriosis

Endometriosis (EM) is a chronic neuroinflammatory disorder that is associated with pain and infertility that affects ∼10% of reproductive-age women. The pathophysiology and etiology of EM remain poorly understood, and diagnostic delays are common. Exploration of the underlying molecular mechanism, as well as novel diagnostic biomarkers and therapeutic targets, is urgently needed. Inflammation is known to play a key role in the development of lesions, which are a defining feature of the disorder. In our research, the CIBERSORT and WGCNA algorithms were used to establish a weighted gene co-expression network and to identify macrophage-related hub genes using data downloaded from the GEO database (GSE11691, 7305). The analysis identified 1,157 differentially expressed genes (DEGs) in EM lesions, of which five were identified as being related to M2 macrophages and were validated as differentially expressed by qRT-PCR and immunohistochemistry (IHC). Of these putative novel biomarker genes, bridging integrator 2 (BIN2), chemokine receptor 5 (CCR5), and macrophage mannose receptor 1 (MRC1) were upregulated, while spleen tyrosine kinase (SYK) and metalloproteinase 12 (ADAM12) were downregulated in ectopic endometria vs. normal endometria. Meanwhile, 23 potentially therapeutic small molecules for EM were obtained from the cMAP database, among which topiramate, isoflupredone, adiphenine, dexverapamil, MS-275, and celastrol were the top six molecules with the highest absolute enrichment values. This is our first attempt to use the CIBERSORT and WGCNA algorithms for the identification of novel Mϕ2 macrophage-related biomarkers of EM. Our findings provide novel insights into the impact of immune cells on the etiology of EM; nevertheless, further investigation of these key genes and therapeutic drugs is needed to validate their effects on EM.

Luteolin Promotes Apoptosis of Endometriotic Cells and Inhibits the Alternative Activation of Endometriosis-Associated Macrophages

Luteolin, a flavonoid present in several fruits, vegetables, nuts, and herbs reportedly exhibits anti-cancer and anti-inflammatory properties. However, the effect of luteolin on endometriosis, a painful condition characterized by the ectopic growth of endometrial tissue and pelvic inflammation, remains elusive. Herein, we observed that luteolin inhibited cell growth and induced apoptosis of 12Z human endometriotic cells by activating caspase-3, -8, and -9. Additionally, luteolin significantly inhibited the expression of key chemokines, C-C motif chemokine ligand 2 (CCL2) and CCL5, required for monocyte/macrophage influx at endometriotic sites. In macrophages stimulated by endometriotic cells, luteolin treatment suppressed the intracellular expression of M2 markers and endometriosis-promoting factors. Collectively, our data suggest that luteolin exerts anti-endometriotic effects by stimulating endometriotic cell apoptosis and hindering the alternative activation of macrophages.

Kiwi Root Extract Inhibits the Development of Endometriosis in Mice by Downregulating Inflammatory Factors

Purpose

To determine whether the kiwi root extract inhibits the development of endometriosis in mice by suppressing inflammatory factors.

Materials and Methods

The mouse model of endometriosis was induced by surgery after which the mice were continuously injected with the drug for 14 days. On the 14^th day, the mice were sacrificed, and the peritoneal fluid was obtained for enzyme-linked immunosorbent assay. Endometrial ectopic tissue was weighed and analyzed by tissue immunochemistry, RT-PCR, western blotting, and gelatin zymography experiment.

Results

Kiwi root extract significantly reduced endometriotic lesion volume and downregulated the proinflammatory cytokines IL-6, IL-8, IL-1β, and TNF-α, as well as the angiogenic factor VEGF-A. It also inhibited the mRNA and protein expression of COX-1 and COX-2, IL-6, TGF-β1, EP₂ receptor, and ER-β in endometriotic lesions but did not affect the expression of MMP-9 and MMP-2.

Conclusions

Kiwi root extract could significantly inhibit the growth of surgery-induced endometriosis in mice. Our results suggest that the kiwi root extract may inhibit the development and progression of ectopic endometrium through disruption of neovascularization and reducing inflammation, which may be beneficial in treating this common gynecological disease.

Alteration of systemic and uterine endometrial immune populations in patients with endometriosis

PROBLEM

Endometriosis is defined as growth of endometrial tissue in ectopic locations; it is associated with infertility and chronic pain and affects ~12% of reproductive-aged women. Although inflammation is known to play a key role in endometriosis, knowledge related to immune phenotypes associated with this disease is lacking. This study aimed to characterize immune profiles in patients with endometriosis, to assess inflammatory mediators, to and determine if surgical and/or hormonal therapies restore immune homeostasis.

METHODS OF STUDY

Samples from nine controls and 20 histologically confirmed endometriosis patients were collected upon surgery and ~1-3 weeks post-surgical intervention. Subjects were either not utilizing hormonal suppression or were currently on monophasic hormonal therapy. Tolerant regulatory T cells (Tregs = natural [nTregs] +inducible [iTregs]) and inflammatory T helper 17 (Th17) cells were identified in peripheral blood via flow cytometry and within the eutopic/ectopic endometrial tissues via immunohistochemistry and real-time-qPCR. Cytokines were assessed via 10-plex-ELISA.

RESULTS

Patients with endometriosis not utilizing hormonal therapy exhibited lower iTregs (tolerant), greater Th17 (inflammatory), and a reduction in Treg/Th17 ratio (P < .05), indicative of systemic inflammation. Treg and Th17 localizations were enhanced within the ectopic endometrial implant, which promotes lesion development. Hormonal therapy decreased systemic and local inflammation (eutopic/ectopic endometrium) via decreased iTregs and Th17 cells in patients with endometriosis (P < .05). Thus, imbalance within immune populations correlated with increased inflammation in patients with endometriosis, which was mitigated by hormonal therapy.

CONCLUSIONS

Patients with endometriosis exhibited systemic and localized inflammation within ectopic and endometrial tissues. Hormonal therapy dampened inflammation caused by disease.

Anti-IL-6 receptor monoclonal antibody as a new treatment of endometriosis

Many pro-inflammatory cytokines especially tumor necrotic factor alpha (TNFα), interleukin (IL)-1β, and IL-6 have crucial role in the pathogenesis of endometriosis. In this study, we investigated the immune-modulatory role of humanized anti-IL-6 receptor monoclonal antibodies in the treatment of endometriosis. This is a prospective, randomized, controlled, blinded study in which Sprague Dawley rats were used as animal model of endometriosis. Animals were randomly divided into two groups, a test group which received tocilizumab (Actemra; Roche, Switzerland) and a control group which received saline. Afterwards, a comparison was done between the eutopic and ectopic endometrium that was excised from both groups, histopathologically and immune-histochemically. Histopathologic assessment and immune-histochemical staining were performed using antibodies against IL-6. Tocilizumab significantly suppressed the volume of endometriotic lesions compared with non-treated rats (P = 0.006) and atrophied the ectopic endometrial-like epithelium (in 42.8% of treated rats vs 0% in the control group). Tocilizumab also decreased the anti-IL-6 receptor immune-histochemical staining intensity in ectopic endometrium (from non to +++ in the test group vs ++ or more in the control group), with no apparent difference in the eutopic one reflecting the down-regulation of IL-6-producing cells in ectopic endometriotic lesions. In rats with induced endometriosis, anti-IL-6 receptor monoclonal antibodies could offer a new horizon of usage of this immune-modulatory biologic drug, used in other autoimmune diseases, in treatment of endometriosis.

Estrogen receptor β upregulates CCL2 via NF-κB signaling in endometriotic stromal cells and recruits macrophages to promote the pathogenesis of endometriosis

STUDY QUESTION

How is the activation of estrogen receptor β (ERβ) in endometriotic stromal cells (ESCs) involved in macrophage recruitment to promote the pathogenesis of endometriosis?

SUMMARY ANSWER

ERβ modulates the production of C-C motif chemokine ligand 2 (CCL2) via nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in ESCs and thus recruits macrophages to ectopic lesions to promote pathogenesis.

WHAT IS KNOWN ALREADY

Macrophages are mainly recruited to the peritoneal cavity to promote the pathogenesis of endometriosis. Recent studies have demonstrated that ERβ plays an important role in the progression of endometriosis through modulating apoptosis and inflammation.

STUDY DESIGN, SIZE, DURATION

An observational study consisting of 22 cases (women with endometriosis, diagnosed by laparoscopy and histological analysis) and 14 controls (without endometriosis) was carried out.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Tissues and stromal cells that were isolated from 22 patients with ovarian endometrioma and deeply infiltrating endometriosis were compared with tissues and stromal cells from 14 patients with normal cycling endometrium using immunohistochemistry, quantitative PCR, Western blot, cell migration assay and cloning formation assay. P values < 0.05 were considered significant, and experiments were repeated in at least three different cell preparations.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed that accumulated macrophages were recruited to the ectopic milieu and mainly adopted an alternatively activated macrophage (M2) phenotype. To reveal the underlying mechanism for this, we conducted a series of experiments and found that high expression of ERβ led to the production of CCL2 via NF-κB signaling and macrophages were recruited to the ectopic milieu. An in vitro co-culture assay also suggested that the recruited macrophages in turn could promote the proliferation and clonogenic ability of ESCs. Overall, the activation of ERβ in ESCs is involved in macrophage recruitment via NF-κB/CCL2 signaling and subsequently appears to promote the pathogenesis of endometriosis.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Due to the limitations of obtaining surgical specimens, endometrioma tissues were collected mainly from women diagnosed with middle to late stage endometriosis. We identified the predominant presence of M2 macrophages in the samples used in our study, but the underlying mechanism of how recruited macrophages acquire the M2 phenotype is undefined.

WIDER IMPLICATIONS OF THE FINDINGS

This work provides novel insight into the mechanism by which ERβ may modulate macrophage infiltration and promote pathogenesis, which may provide a new therapeutic target for endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Natural Science Foundation of China (81671430). The authors have no conflicts of interest.

MicroRNAs in endometriosis: biological function and emerging biomarker candidates†

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

Fractalkine/CX3CR1 Contributes to Endometriosis-Induced Neuropathic Pain and Mechanical Hypersensitivity in Rats

Pain is the most severe and common symptom of endometriosis. Its underlying pathogenetic mechanism is poorly understood. Nerve sensitization is a particular research challenge, due to the limitations of general endometriosis models and sampling nerve tissue from patients. The chemokine fractalkine (FKN) has been demonstrated to play a key role in various forms of neuropathic pain, while its role in endometriotic pain is unknown. Our study was designed to explore the function of FKN in the development and maintenance of peripheral hyperalgesia and central sensitization in endometriosis using a novel endometriosis animal model developed in our laboratory. After modeling, behavioral tests were carried out and the optimal time for molecular changes was obtained. We extracted ectopic tissues and L4-6 spinal cords to detect peripheral and central roles for FKN, respectively. To assess morphologic characteristics of endometriosis-like lesions-as well as expression and location of FKN/CX3CR1-we performed H&E staining, immunostaining, and western blotting analyses. Furthermore, inhibition of FKN expression in the spinal cord was achieved by intrathecal administration of an FKN-neutralizing antibody to demonstrate its function. Our results showed that implanted autologous uterine tissue around the sciatic nerve induced endometriosis-like lesions and produced mechanical hyperalgesia and allodynia. FKN was highly expressed on macrophages, whereas its receptor CX3CR1 was overexpressed in the myelin sheath of sciatic nerve fibers. Overexpressed FKN was also observed in neurons. CX3CR1/pp38-MAPK was upregulated in activated microglia in the spinal dorsal horn. Intrathecal administration of FKN-neutralizing antibody not only reversed the established mechanical hyperalgesia and allodynia, but also inhibited the expression of CX3CR1/pp38-MAPK in activated microglia, which was essential for the persistence of central sensitization. We concluded that the FKN/CX3CR1 signaling pathway might be one of the mechanisms of peripheral hyperalgesia in endometriosis, which requires further studies. Spinal FKN is important for the development and maintenance of central sensitization in endometriosis, and it may further serve as a novel therapeutic target to relieve persistent pain associated with endometriosis.