Endometrial stromal cell inflammatory phenotype during severe ovarian endometriosis as a cause of endometriosis-associated infertility

m6A methyltransferase METTL3 inhibits endometriosis by regulating alternative splicing of MIR17HG

In brief

Inflammation and abnormal immune response are the key processes in the development of endometriosis (EMs), and m6A modification can regulate the inflammatory response. This study reveals that METTL3-mediated N6-methyladenosine (m6A) modification plays an important role in EMs.

Abstract

m6A modification is largely involved in the development of different diseases. This study intended to investigate the implication of m6A methylation transferase methyltransferase like 3 (METTL3) in EMs. EMs- and m6A-related mRNAs and long non-coding RNAs were identified through bioinformatics analysis. Next, EM mouse models established by endometrial autotransplantation and mouse endometrial stromal cell (mESC) were prepared and treated with oe-METTL3 or sh-MIR17HG for pinpointing the in vitro and in vivo effects of METTL3 on EMs in relation to MIR17HG through the determination of mESC biological processes as well as estradiol (E2) and related lipoprotein levels. We demonstrated that METTL3 and MIR17HG were downregulated in the EMs mouse model. Overexpression of METTL3 suppressed the proliferation, migration, and invasion of mESCs. In addition, METTL3 enhanced the expression of MIR17HG through m6A modification. Moreover, METTL3 could inhibit the E2 level and alter related lipoprotein levels in EMs mice through the upregulation of MIR17HG. The present study highlighted that the m6A methylation transferase METTL3 prevents EMs progression by upregulating MIR17HG expression.

Overexpression of ErbB-1 (EGFR) Protein in Eutopic Endometrium of Infertile Women with Severe Ovarian Endometriosis during the ‘Implantation Window’ of Menstrual Cycle

The strong association between endometriosis and infertility is of high clinical significance. High proliferative bias in eutopic endometrium during the secretory phase is a hallmark of endometriosis, which may result in high occurrence of implantation failure and resultant infertility in endometriosis. The ErbB family of proteins regulates the proliferation capacity in the endometrium, potentially causing endometrial hostility to the implantation process in endometriosis. However, our knowledge regarding the involvement of the ErbB family in human endometrium during the window of implantation (WOI) in endometriosis-associated infertility is scant. In the present study, the cellular profiles of immunopositive ErbBs-1 to -4 in the endometrium of endometriosis-free, infertile women (Group 1; n = 11) and in eutopic endometrium of infertile women diagnosed with stage IV ovarian endometriosis (Group 2; n = 13) during the mid-secretory phase were compared using standardized guidelines. Computer-aided standardized combinative analysis of immunoprecipitation in different compartments revealed an overexpression of ErbB-1 in the epithelial, stromal and vascular compartments, along with marginally higher ErbB-3 expression (p < 0.06) in the vascular compartment and ErbB-4 expression (p < 0.05) in the glandular epithelium and stroma in the endometrium during the WOI in women with primary infertility associated with stage IV ovarian endometriosis compared with disease-free endometrium of control infertile women. It appears that changes in ErbBs in the eutopic endometrium during WOI induce anomalous proliferative, inflammatory and angiogenic activities in it, which can antagonize endometrial preparation for embryo implantation in endometriosis. This knowledge appears usable in strategizing methods for the treatment of endometriosis-associated infertility, as well as preempting the oncogenic potential of endometriosis.

LncRNA HOTAIR regulates cell invasion and migration in endometriosis through miR-519b-3p/PRRG4 pathway

Endometriosis is a common benign disease in gynecology and has malignant biological behaviors, such as hyperplasia, invasion, metastasis, and recurrence. However, the pathogenesis of endometriosis remains unclear. The present study aimed to investigate whether LncRNA HOTAIR regulates cell invasion and migration in endometriosis by regulating the miR-519b-3p/PRRG4 pathway. The qRT-PCR results showed that the average relative expression of LncRNA HOTAIR was much higher in ectopic endometrial tissues than in eutopic endometrial tissues. Scratch and transwell assays showed that the cell migration and invasion ability of LncRNA HOTAIR overexpression group was significantly higher than those in the control group. Conversely, the LncRNA HOTAIR knockdown group showed the opposite results. Bioinformatics analysis suggested that the downstream target genes of LncRNA HOTAIR were miR-519b-3p and Prrg4. Knockdown of LncRNA HOTAIR can reduce the up-regulation of Prrg4 by miR-519b-3p and then inhibit the invasion and migration ability of endometrial stromal cells. In Conclusion, LncRNA HOTAIR can regulate the ability of invasion and migration of endometrial stromal cells, and its mechanism is proved by regulating the miR-519b-3p/PRRG4 pathway.

Circ_0004712 promotes endometriotic epithelial cell proliferation, migration and invasion by regulating miR-488-3p/ROCK1 axis in vitro

Recent evidence indicates that circular RNAs (circRNAs) play crucial regulatory roles in the pathogenesis and development of endometriosis. Circ_0004712 was found to be differentially expressed in endometriosis. However, the detailed function and mechanism of circ_0004712 in endometriosis are still unclear. Quantitative real-time polymerase chain reaction and Western blot were used for the detection of circ_0004712, miR-488-3p and ROCK1 (Rho Associated Coiled-Coil Containing Protein Kinase 1) levels. In vitro experiments in endometrial endothelial cells were performed by cell counting kit-8, EdU, transwell, wound healing assays, and flow cytometry, respectively. The molecular mechanism of circ_0004712 function was investigated using bioinformatics target predication, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assays. The expression of circ_0004712 was higher in endometriotic endometrial tissues and epithelial cells. Knockdown of circ_0004712 suppressed cell proliferation, migration, invasion, EMT process and induced apoptosis in ectopic endometrial epithelial cells in vitro. Mechanistically, circ_0004712 acted as a ceRNA to sponge miR-488-3p, thus elevating the expression of ROCK1, which was confirmed to be a target of miR-488-3p. Rescue experiments suggested that miR-488-3p inhibition reversed the inhibitory effects of circ_0004712 silencing on cell growth and metastasis. Moreover, miR-488-3p restoration restrained the proliferation and metastasis in ectopic endometrial epithelial cells, which were attenuated by ROCK1 overexpression. Circ_0004712 knockdown suppressed the proliferation and metastasis of ectopic endometrial epithelial cells via miR-488-3p/ROCK1 axis in vitro, suggesting a new insight into the pathogenesis of endometriosis.

CLTA-4 Expression is Associated with the Maintenance of Chronic Inflammation in Endometriosis and Infertility

Altered immune mechanisms are implicated in the pathogenesis of endometriosis. CTLA-4 is a membrane receptor that favors the anergic state of lymphocytes, which may disrupt the immune system response in the endometriotic environment. In this study, we examined the expression of CTLA-4 on T and B cells by flow cytometry and its levels in blood serum and peritoneal fluid by ELISA. Levels of CTLA-4+ T cells were significantly higher in patients with more advanced endometriosis than in those with less advanced disease. Additionally, the negative correlation of CTLA-4⁺ T lymphocytes and the percentage of NK and NKT-like cells in women with endometriosis and infertility may indicate a different etiopathogenesis of endometriosis accompanying infertility. Our findings shed light on the potential of CTLA-4 in developing new diagnostic and therapeutic approaches in endometriosis management.

A robust permutation test for the concordance correlation coefficient

In this work, we developed a robust permutation test for the concordance correlation coefficient (ρ_c) for testing the general hypothesis H₀ : ρ_c = ρ_c(0). The proposed test is based on an appropriately studentized statistic. Theoretically, the test is proven to be asymptotically valid in the general setting when two paired variables are uncorrelated but dependent. This desired property was demonstrated across a range of distributional assumptions and sample sizes in simulation studies, where the test exhibits robust type I error control in all settings tested, even when the sample size is small. We demonstrated the application of this test in two real world examples across cardiac output measurements and endocardiographic imaging.

Pathophysiological Basis of Endometriosis-Linked Stress Associated with Pain and Infertility: A Conceptual Review

Women with endometriosis are often under stress due to the associated pain, infertility, inflammation-related and other comorbidities including cancer. Additionally, these women are also under stress due to taboos, myths, inter-personal troubles surrounding infertility and pain of the disease as well as due to frequent incidences of missed diagnosis and treatment recurrence. Often these women suffer from frustration and loss of valuable time in the prime phase of life. All these complexities integral to endometriosis posit a hyperstructure of integrative stress physiology with overt differentials in effective allostatic state in women with disease compared with disease-free women. In the present review, we aim to critically examine various aspects of pathophysiological basis of stress surrounding endometriosis with special emphasis on pain and subfertility that are known to affect the overall health and quality of life of women with the disease and promising pathophysiological basis for its effective management.