Immunopathogenesis of endometriosis - a novel look at an old problem

ARG2 knockdown promotes G0/G1 cell cycle arrest and mitochondrial dysfunction in adenomyosis via regulation NF-κB and Wnt/Β-catenin signaling cascades

BACKGROUND

Adenomyosis is a common gynecological disease, characterized by overgrowth of endometrial glands and stroma in the myometrium, however its exact pathophysiology still remains uncertain. Emerging evidence has demonstrated the elevated level of arginase 2 (ARG2) in endometriosis and adenomyosis. This study aimed to determine whether ARG2 involved in mitochondrial function and epithelial to mesenchymal transition (EMT) in adenomyosis and its potential underlying mechanisms.

MATERIALS AND METHODS

RNA interference was used to inhibit ARG2 gene, and then Cell Counting Kit (CCK-8) assay and flow cytometery were performed to detect the cell proliferation capacity, cell cycle, and apoptosis progression, respectively. The mouse adenomyosis model was established and RT-PCR, Western blot analysis, mitochondrial membrane potential (Δψm) detection and mPTP opening evaluation were conducted.

RESULTS

Silencing ARG2 effectively down-regulated its expression at the mRNA and protein levels in endometrial cells, leading to decreased enzyme activity and inhibition of cell viability. Additionally, ARG2 knockdown induced G0/G1 cell cycle arrest, promoted apoptosis, and modulated the expression of cell cycle- and apoptosis-related regulators. Notably, the interference with ARG2 induces apoptosis by mitochondrial dysfunction, ROS production, ATP depletion, decreasing the Bcl-2/Bax ratio, releasing Cytochrome c, and increasing the expression of Caspase-9/-3 and PARP. In vivo study in a mouse model of adenomyosis demonstrated also elevated levels of ARG2 and EMT markers, while siARG2 treatment reversed EMT and modulated inflammatory cytokines. Furthermore, ARG2 knockdown was found to modulate the NF-κB and Wnt/β-catenin signaling pathways in mouse adenomyosis.

CONCLUSION

Consequently, ARG2 silencing could induce apoptosis through a mitochondria-dependent pathway mediated by ROS, and G0/G1 cell cycle arrest via suppressing NF-κB and Wnt/β-catenin signaling pathways in Ishikawa cells. These findings collectively suggest that ARG2 plays a crucial role in the pathogenesis of adenomyosis and may serve as a potential target for therapeutic intervention.

MCP-1 exerts the inflammatory response via ILK activation during endometriosis pathogenesis

AIMS

MCP-1 has been shown to be elevated in endometriosis. ILK functions in several cellular events and interacts with MCP-1-signaling. In the current study, we evaluated the role of MCP-1-ILK signaling in human endometriotic cell's (Hs832(C).TCs) potential for colonization, invasion, adhesion, etc. and differentiation of macrophage along with inflammation in an endometriosis mouse model.

MATERIALS AND METHODS

A mouse model of endometriosis with elevated levels of MCP-1 was developed by injecting MCP-1. We examined the migration, adhesion, colonization and invasion of Hs832(C).TCs in response to MCP-1-ILK signaling. We also examined the differentiation of THP-1 cells to macrophage in response to MCP-1-ILK signaling.

KEY FINDINGS

We observed that MCP-1 increased Ser246 phosphorylation of ILK in Hs832(C).TCs and enhanced the migration, adhesion, colonization, and invasion of Hs832(C).TCs. In the mouse model of endometriosis, we found elevated chemokines (CCL-11, CCL-22 and CXCL13) levels. An increased level of MCP-1 mediated ILK activation, leading to increased inflammatory reaction and infiltration of residential and circulatory macrophages, and monocyte differentiation, but suppressed the anti-inflammatory reaction. The inhibitor (CPD22) of ILK reversed the MCP-1-mediated action by restoring Hs832(C).TCs and THP-1 phenotype. ILK inhibition in a mouse model of endometriosis reduced the effects of MCP-1 mediated pro-inflammatory cytokines, but increased anti-inflammatory response along with T-regulatory and T-helper cell restoration.

SIGNIFICANCE

Targeting ILK restores MCP-1 milieu in the peritoneal cavity and endometrial tissues, reduces the inflammatory response, improves the T-regulatory and T-helper cells in the endometriosis mouse model and decreases the migration, adhesion, colonization and invasion of endometriotic cells.

Eating for Optimization: Unraveling the Dietary Patterns and Nutritional Strategies in Endometriosis Management

Endometriosis is a chronic gynecological disorder affecting millions of women worldwide, causing chronic pelvic pain, dyspareunia, dysmenorrhea, and infertility, and severely impacting their quality of life. Treatment primarily involves hormonal therapies and surgical excision, but high recurrence rates and the economic burden are substantial. With these challenges, significant discussion surrounds the potential role of dietary patterns in managing endometriosis, making it necessary to bridge this critical gap. This review investigates the current scientific evidence on the dietary patterns (eg, Mediterranean, vegetarian, anti-inflammatory, low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols [low-FODMAP], and Western-style diets) associated with endometriosis and provides a concise, yet thorough, overview on the subject. In addition, antioxidants, microbiota, and artificial intelligence (AI) and their potential roles were also evaluated as future directions. An electronic-based search was performed in MEDLINE, Embase, Cochrane Library, CINAHL, ClinicalTrials.gov, Scopus, and Web of Science. The current data on the topic indicate that a diet based on the Mediterranean and anti-inflammatory diet pattern, rich in dietary fiber, omega-3 fatty acids, plant-based protein, and vitamins and minerals, has a positive influence on endometriosis, yielding a promising improvement in patient symptoms. Preclinical investigations and clinical trials indicate that dietary antioxidants and gut microbiota modulation present potential new approaches in managing endometriosis. Also, AI may offer a promising avenue to explore how dietary components interact with endometriosis. Ultimately, considering genetic and lifestyle factors, a healthy, balanced, personalized approach to diet may offer valuable insights on the role of diet as a means of symptom improvement, facilitating the utilization of nutrition for the management of endometriosis.

Altered Monocyte and Lymphocyte Phenotypes Associated with Pathogenesis and Clinical Efficacy of Progestogen Therapy for Peritoneal Endometriosis in Adolescents

Background: Immunological imbalances characteristic of endometriosis may develop as early as the primary manifestations of the disease in adolescence. Objective: To evaluate subpopulation dynamics of monocytes and lymphocytes in peripheral blood and peritoneal fluid of adolescents with peritoneal endometriosis at diagnosis and after 1-year progestogen therapy. Methods: This study included 70 girls, 13-17 years old, diagnosed laparoscopically with peritoneal endometriosis (n = 50, main group) or paramesonephric cysts (n = 20, comparison group). Phenotypes of monocytes and lymphocytes of the blood and macrophages of the peritoneal fluid were analyzed by flow cytometry at diagnosis and during progestogen therapy. Results: Differential blood counts of CD16+ (p < 0.001) and CD86+ (p = 0.017) monocytes were identified as independent risk factors for peritoneal endometriosis in adolescents. During the treatment, cytotoxic lymphocytes CD56dimCD16bright (p = 0.049) and CD206+ monocytes (p < 0.001) significantly increased while CD163+ monocytes decreased in number (p = 0.017). The CD56dimCD16bright blood counts before (p < 0.001) and during progestogen therapy (p = 0.006), as well as CD206+ blood counts during the treatment (p = 0.038), were associated with the efficacy of pain relief after 1-year progestogen therapy. Conclusions: Adolescents with peritoneal endometriosis have altered counts of pro- and anti-inflammatory monocytes and lymphocytes both before and after 1-year progestogen therapy, correlating with treatment efficacy and justifying long-term hormonal therapy.

The PD-1/PD-L1 Gateway: Peripheral Immune Regulation in the Pathogenesis of Endometriosis

Endometriosis is a chronic inflammatory disease characterized by the presence of endometrial-like tissue outside the uterine cavity, causing pain and infertility. Despite the rather unclear etiopathogenesis, recent studies suggest the involvement of the immune system in the development and progression of endometriosis. The role of the PD-1/PD-L1 axis in the modulation of the immune response in this disease seems to be particularly interesting. This preliminary study aimed to investigate the expression of PD-1 and PD-L1 on T and B lymphocytes in peripheral blood in patients with endometriosis to assess their potential impact on disease progression. Our study involved peripheral blood samples from 80 patients diagnosed with endometriosis and 20 healthy women as a control group were analyzed. Flow cytometry was used to assess the expression of PD-1 and PD-L1 on T and B lymphocytes, and enzyme-linked immunosorbent assays were used to assess their soluble forms in serum and peritoneal fluid.in our research we observe significantly higher expression of PD-1 and PD-L1 on T and B lymphocytes was found in patients with endometriosis compared to the control group. Higher expression of both tested molecules correlated with the stage of endometriosis. The results of our preliminary studies indicate a potential role of the PD-1/PD-L1 axis in the modulation of the immune response in endometriosis. Modified expression of these proteins may contribute to immune evasion by ectopic tissues, supporting their survival and proliferation. These findings suggest that targeting PD-1/PD-L1 could be explored as a therapeutic option for the treatment of endometriosis, though further research with larger sample sizes is necessary to confirm these results and clarify the role of PD-1/PD-L1 in the pathogenesis of the disease.

The role of innate and adaptive immunity in endometriosis

The innate and adaptive immune systems are the two key branches that determine host protection at all mucosal surfaces in human body, including the female reproductive tract. The pattern recognition receptors within the host that recognize pathogen-associated molecular patterns are expressed on the cells of the innate immune system. Rapidly reactive, theinnate immune system, responds immediately to the presence of infectious or other non-self agents, thereby launching an inflammatory response to protect the host until the activation of slower adaptive immune system. Macrophages, dendritic cells, and toll-like receptors are integral components of the innate immune system. In contrast, T-helper (Th1/Th2/Th17) cells and regulatory T (Treg) cells are the primary components of adaptive immune system. Studies showed that the growth and progression of endometriosis continue even in unilateral ovariectomized animal suggesting that besides ovarian steroid hormones, the growth of endometriosis could be regulated by innate/adaptive immune systems in pelvic environment. Recent reports demonstrated a potential role of Th1/Th2/Th17/Treg cells either individually or collectively in the initiation, maintenance, and progression of endometriosis. Herewe review the fundamental knowledge of innate and adaptive immunity and elaborate the role of innate and adaptive immunity in endometriosis based on both human and experimental data.

Beyond the surface: Does stage I-II endometriosis impact fertility? Exploring the challenges of mild disease

Endometriosis is one of the most common gynecologic conditions that women face throughout their lives. Despite advances in technology, diagnosis and treatment of this relapsing and remitting condition is still challenging for many women. This review focuses on literature pertaining to minimal/mild (stage I/II) endometriosis and its impact on fertility. The effectiveness of medical interventions to improve infertility and obstetric outcomes in both natural and assisted reproductive technologies cycles remains debated. The recent ESHRE guidelines suggests that operative laparoscopy could be considered for rASRM stage I/II endometriosis as it improves ongoing pregnancy rates.

Reproductive Immunology and Pregnancy 3.0

This Special Issue, the third dedicated to reproductive immunology and pregnancy, is another review of the latest trends in research topics in this field [...].

Tanshinone ⅡA participates in the treatment of endometriosis by regulating adhesion, invasion, angiogenesis and inhibition of PI3K/Akt/mTOR signaling pathway

Endometriosis (EMs) is a common gynecological disorder characterized by abnormal growth of the endometrial stroma and glands outside the uterus. Tanshinone IIA, the active component of Chinese medicine Danshen (Salvia miltiorrhiza Bge.), has a number of pharmacological effects such as anti‑inflammation and anti‑oxidation and serves a significant role in the treatment of EMs. In the present study, network pharmacology and experimental validation were used to elucidate the potential mechanism of tanshinone IIA for treating EMs. Several databases were used to collect information on EMs and tanshinone IIA and cross‑targets for tanshinone IIA and EMs finally obtained. A total of 64 common targets were found between tanshinone IIA and EMs. Subsequently, a protein‑protein interaction network was constructed, a total of 14 core targets were screened for enrichment analysis. Furthermore, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed. The network pharmacology showed that intercellular adhesion molecule (ICAM)‑1, MMP‑9 and VEGF are the core targets while PI3K/AKT pathway and mTOR pathway are the main signaling pathways through which tanshinone IIA regulates relevant biological processes to intervene in EMs. Finally, the therapeutic role and mechanism of tanshinone IIA on EMs was verified in vivo. Female Sprague‑Dawley rats were treated by autologous transplantation to establish EMs. Serum inflammatory factors were detected by enzyme‑linked immunosorbent assay (ELISA). The expression of ICAM‑1, MMP‑9 and VEGF in ectopic endometrial tissues of rats was determined by immunohistochemical. The expression of PI3K/Akt/mTOR pathway‑related proteins and genes was detected by western blotting and quantitative PCR. It was found that tanshinone IIA treatment significantly decreased the formation of ectopic endometrium by reducing serum levels of TNF‑α and IL‑1β, and down regulating the levels of ICAM‑1, MMP‑9 and VEGF in ectopic uterine tissue. In addition, tanshinone IIA can also block the activation of PI3K/Akt/mTOR signaling pathway by reducing the expression of related proteins and genes. In conclusion, tanshinone IIA can regulate adhesion, invasion and angiogenesis, thereby improving the pathological morphology of ectopic endometrium and inhibiting the formation of ectopic lesions. The PI3K/Akt/mTOR signaling pathway may play a key role in controlling this process.

The deviations of CD4 + T cells during peripheral blood and peritoneal fluid of endometriosis: a systematic review and meta-analysis

OBJECTIVE

To assess whether endometriosis (EMs) was related to systematic and/or local deviations of cluster of differentiation (CD)4 + T cells.

METHODS

Until November 2022, we enrolled a total of 1363 EMs and 1564 healthy women from 32 studies who met the inclusion criteria.

RESULTS

After systematically retrieving the literature, we identified 1086 citations and 32 case-control studies were enrolled. Cumulative results suggested that there were insignificant deviations of CD4 + T cells during peripheral blood (PB) between EMs and healthy women (RR: - 0.83, I2 = 99%, p = 0.65), also no statistically significant difference was found between mild and severe EMs (RR: 3.19, I2 = 94%, p = 0.19). We also found insignificant deviations of CD4 + /CD8 + during PB between EMs and healthy women (RR: 0.09, I2 = 99%, p = 0.39), and between mild and severe EMs (RR: - 0.16, I2 = 99%, p = 0.29). The results might suggest that there was no significant correlation between EMs and systematic deviations of CD4 + T cells. When it came to local deviation during peritoneal fluid (PF), the polled results suggested that the frequency of CD4 + T cells during EMs was significantly lower than healthy women (RR: - 5.38, I2 = 93%, p = 0.01), and the ratio of CD4 + /CD8 + during EMs was significantly lower than healthy women (RR: - 0.13, I2 = 0%, p < 0.0001). However, there were insignificant deviations of CD4 + during PF between mild and severe EMs (RR: 1.65, I2 = 53%, p = 0.15), also there was an insignificant difference of CD4 + /CD8 + between mild and severe EMs (RR: - 0.09, I2 = 14%, p = 0.19). EMs might be closely related to local deviations of CD4 + T cells.

CONCLUSION

There was no obvious correlation between EMs and systematic deviations of CD4 + T cells, EMs might be closely related to local deviations of CD4 + T cells. Further study on the functional deviations and subpopulation distribution of CD4 + T cells is urgently needed.

Host immunity and KLF 11 deficiency together promote fibrosis in a mouse model of endometriosis

BACKGROUND

Endometriosis is a debilitating disease typically characterized by prolific fibrotic scarring. Earlier we reported downregulation of two transcription factors belonging TGF-βR signaling pathway Sp/Krüppel-like factor 11 (KLF11) and 10 (KLF10) in human endometriosis lesions. Here we investigated the role of these nuclear factors and immunity in the scaring fibrosis associated with endometriosis.

METHODS

We used a well characterized experimental mouse model of endometriosis. WT, KLF10 or KLF11 deficient mice were compared. The lesions were evaluated histologically, fibrosis was quantified with Masons' Trichome staining, immune-infiltrates were quantified by immunohistochemistry, peritoneal adhesions were score, gene expression was evaluated by bulk RNA sequencing.

RESULTS

Intense fibrotic reactions and large changes in gene expression were detected in KLF11 deficient implants associated with squamous metaplasia of the ectopic endometrium, as compared to KLF10 deficient or WT implants. Fibrosis was mitigated with pharmacologic agents that blocked histone acetylation or TGF-βR signaling or with genetic deficiency for SMAD3. The lesions were richly infiltrated with T-cells, regulatory T-cells, and innate immune cells. Fibrosis was exacerbated when implants expressed ectopic genes implicating autoimmunity as a major factor contributing to the scaring fibrosis.

CONCLUSIONS

Our findings identify KLF11 and TGF-βR signaling as cell intrinsic mechanisms and autoimmune responses as cell extrinsic mechanisms of scaring fibrosis in ectopic endometrium lesions.

GENERAL SIGNIFICANCE

Immunological factors associated with inflammation and tissue repair drive scaring fibrosis in experimental endometriosis, providing the rationale for immune therapy of endometriosis.

Insight into the Potential Mechanisms of Endocrine Disruption by Dietary Phytoestrogens in the Context of the Etiopathogenesis of Endometriosis

Phytoestrogens (PEs) are estrogen-like nonsteroidal compounds derived from plants (e.g., nuts, seeds, fruits, and vegetables) and fungi that are structurally similar to 17β-estradiol. PEs bind to all types of estrogen receptors, including ERα and ERβ receptors, nuclear receptors, and a membrane-bound estrogen receptor known as the G protein-coupled estrogen receptor (GPER). As endocrine-disrupting chemicals (EDCs) with pro- or antiestrogenic properties, PEs can potentially disrupt the hormonal regulation of homeostasis, resulting in developmental and reproductive abnormalities. However, a lack of PEs in the diet does not result in the development of deficiency symptoms. To properly assess the benefits and risks associated with the use of a PE-rich diet, it is necessary to distinguish between endocrine disruption (endocrine-mediated adverse effects) and nonspecific effects on the endocrine system. Endometriosis is an estrogen-dependent disease of unknown etiopathogenesis, in which tissue similar to the lining of the uterus (the endometrium) grows outside of the uterus with subsequent complications being manifested as a result of local inflammatory reactions. Endometriosis affects 10-15% of women of reproductive age and is associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. In this review, the endocrine-disruptive actions of PEs are reviewed in the context of endometriosis to determine whether a PE-rich diet has a positive or negative effect on the risk and course of endometriosis.

The Comparative Invasiveness of Endometriotic Cell Lines to Breast and Endometrial Cancer Cell Lines

Endometriosis is an invasive condition that affects 10% of women (and people assigned as female at birth) worldwide. The purpose of this study was to characterize the relative invasiveness of three available endometriotic cell lines (EEC12Z, iEc-ESCs, tHESCs) to cancer cell lines (MDA-MB-231, SW1353 and EM-E6/E7/TERT) and assess whether the relative invasiveness was consistent across different invasion assays. All cell lines were subjected to transwell, spheroid drop, and spheroid-gel invasion assays, and stained for vimentin, cytokeratin, E-Cadherin and N-Cadherin to assess changes in expression. In all assays, endometriotic cell lines showed comparable invasiveness to the cancer cell lines used in this study, with no significant differences in invasiveness identified. EEC12Z cells that had invaded within the assay periods showed declines in E-Cadherin expression compared to cells that had not invaded within the assay period, without significant changes in N-Cadherin expression, which may support the hypothesis that an epithelial-to-mesenchymal transition is an influence on the invasiveness shown by this peritoneal endometriosis cell line.

The Role of Dietary Fats in the Development and Treatment of Endometriosis

Endometriosis is an estrogen-dependent disease in women of childbearing age that affects approximately 5–15% of the female population. The etiology of endometriosis is complex, multifaceted, and not fully understood. In endometriosis, which is an estrogen-related chronic inflammatory condition, estrogen plays a major role in endometrial cellular growth. High estrogen levels could be another risk factor for developing endometriosis. The aim of this review is to update knowledge on the impact of dietary fats on the development of endometriosis and chronic inflammation in women with endometriosis and diet therapy. Dietary fat may be linked with the progression and development of endometriosis, but studies have been contradictory due to various issues including sample size, different study designs, and different methodological aspects. Results have shown that the risk of endometriosis may increase with a higher consumption of products rich in saturated fats, especially palmitic acid and trans-unsaturated fatty acids. Monounsaturated fats and omega-3 polyunsaturated fatty acids may likely be connected with a lower risk of developing endometriosis and with reductions in the severity of disease. Monounsaturated fats, omega-3 polyunsaturated fatty acids, and a suitable eicosapentaenoic acid to arachidonic acid ratio can be used in diet therapy to improve quality of life by reducing pain and inflammation. Further research is needed in order to fully understand the influence of dietary fats on the risk of development of this disease.

Review of the Potential Therapeutic Effects and Molecular Mechanisms of Resveratrol on Endometriosis

Endometriosis is a hormone-dependent inflammatory disease characterized by the existence of endometrial tissues outside the uterine cavity. Pharmacotherapy and surgery are the current dominant management options for endometriosis. The greater incidence of recurrence and reoperation after surgical treatment as well as the adverse effects of medical approaches predispose patients to potential limitations for their long-term usage. Consequently, it is essential to explore novel supplementary and alternative drugs to ameliorate the therapeutic outcomes of endometriotic patients. Resveratrol is a phenolic compound that has attracted increasing interest from many researchers due to its pleiotropic biological activities. Here, we review the possible therapeutic efficacies and molecular mechanisms of resveratrol against endometriosis based on in vitro, animal, and clinical studies. The potential mechanisms of resveratrol include anti-proliferative, pro-apoptotic, anti-angiogenic, anti-oxidative stress, anti-invasive and anti-adhesive effects, thereby suggesting that resveratrol is a promising candidate for endometriosis. Because most studies have investigated the effectiveness of resveratrol on endometriosis via in vitro trials and/or experimental animal models, further high-quality clinical trials should be undertaken to comprehensively estimate the clinical application feasibility of resveratrol on endometriosis.

I Am the 1 in 10-What Should I Eat? A Research Review of Nutrition in Endometriosis

Endometriosis is a chronic, painful, estrogen-related inflammatory disease that affects approximately 10% of the female population. Endometriosis has a significant negative impact on quality of life. Nutrition may be involved in the development and severity of endometriosis. The purpose of this paper is to discuss in detail the nutritional recommendations for patients with endometriosis. This article discusses the importance of nutrients such as polyphenols, vitamins C, D and E, PUFAs, and iron in the development of endometriosis. Alternative diets, such as the Mediterranean, anti-inflammatory, vegetarian, low-nickel and low-FODMAP diets, have also been presented in the context of their potential beneficial effects on the course of endometriosis.

Copaiba Oil Resin Exerts an Additive Effect to Babassu Oil on Behavioral Changes in Human Endometriotic Cell Cultures

Background: Current drugs for the treatment of endometriosis are not able to completely cure the condition, and significant side effects hinder the continuation of treatment. Therefore, it is necessary to search for new drug candidates. In the present paper, the use of plant extracts is highlighted. Babassu oil and Copaiba oil resin have several therapeutic properties. We investigated the in vitro effects of two nanoemulsions containing oil extracted from Babassu (Orbignya speciosa) nuts (called SNEDDS-18) and/or oil resin extracted from Copaiba trunk (Copaifera langsdorffii) (called SNEDDS-18/COPA) on cultured human eutopic endometrium stromal cells from endometrial biopsies of patients without (CESC) and with (EuESC) endometriosis as well as human stromal cells from biopsies of endometriotic lesions (EctESC). Methods: CESC, EuESC, and EctESC were taken and treated with SNEDDS-18 and SNEDDS-18/COPA to evaluate their effects on cytotoxicity, cell morphology, proliferation, and signaling pathways. Results: After 48 h of incubation with SNEDDS-18 and SNEDDS-18/COPA, cell viability and proliferation were inhibited, especially in EctESC. The lowest concentration of both nanoemulsions reduced cell viability and proliferation and broke down the cytoskeleton in EctESCs. After 24 h of treatment a decrease in IL-1, TNF-α, and MCP-1 was observed, as well as an increase in IL-10 production. Conclusions: Both nanoemulsions can affect endometriotic stromal cell behaviors, thus revealing two potential candidates for new phytotherapeutic agents for the management of endometriosis.

Epigenetic regulation and T-cell responses in endometriosis – something other than autoimmunity

Endometriosis is defined as the presence of endometrial-like glands and stroma located outside the uterine cavity. This common, estrogen dependent, inflammatory condition affects up to 15% of reproductive-aged women and is a well-recognized cause of chronic pelvic pain and infertility. Despite the still unknown etiology of endometriosis, much evidence suggests the participation of epigenetic mechanisms in the disease etiopathogenesis. The main rationale is based on the fact that heritable phenotype changes that do not involve alterations in the DNA sequence are common triggers for hormonal, immunological, and inflammatory disorders, which play a key role in the formation of endometriotic foci. Epigenetic mechanisms regulating T-cell responses, including DNA methylation and posttranslational histone modifications, deserve attention because tissue-resident T lymphocytes work in concert with organ structural cells to generate appropriate immune responses and are functionally shaped by organ-specific environmental conditions. Thus, a failure to precisely regulate immune cell transcription may result in compromised immunological integrity of the organ with an increased risk of inflammatory disorders. The coexistence of endometriosis and autoimmunity is a well-known occurrence. Recent research results indicate regulatory T-cell (Treg) alterations in endometriosis, and an increased number of highly active Tregs and macrophages have been found in peritoneal fluid from women with endometriosis. Elimination of the regulatory function of T cells and an imbalance between T helper cells of the Th1 and Th2 types have been reported in the endometria of women with endometriosis-associated infertility. This review aims to present the state of the art in recognition epigenetic reprogramming of T cells as the key factor in the pathophysiology of endometriosis in the context of T-cell-related autoimmunity. The new potential therapeutic approaches based on epigenetic modulation and/or adoptive transfer of T cells will also be outlined.