Suppression of PRDX4 inhibits cell proliferation and invasion of ectopic endometrial stromal cells in endometriosis

Iron overload increases the sensitivity of endometriosis stromal cells to ferroptosis via a PRC2-independent function of EZH2

Given the high concentration of iron in the micro-environment of ovarian endometriosis, it is plausible to hypothesize that ectopic endometrial cells may be more susceptible to undergoing ferroptosis. Manipulation of ferroptosis has been explored as a potential therapeutic strategy to treat related diseases. In this study, we examined the impact on ectopic endometrial stromal cells (EESCs) of iron overload and an inducer of ferroptosis. We found that the iron concentration in the ovarian endometriosis was much higher than control samples. Treatment of cultured EESCs with ferric ammonium citrate (FAC) increase the sensitivity to undergo ferroptosis. By analyzing the RNA-seq results, it was discovered that zeste 2 polycomb repressive complex 2 subunit (EZH2) was significantly downregulated in ferroptosis induced EESCs. Moreover, overexpression of EZH2 effectively prevented the induction of ferroptosis. In addition, the activity or expression of EZH2 is directly and specifically inhibited by the methyltransferase inhibitor GSK343, which raises the sensitivity of stromal cells to ferroptosis. Taken together, our findings revealed that EZH2 act as a suppressor in the induced cell ferroptosis through a PRC2-independent methyltransferase mechanism. Therefore, blocking EZH2 expression and inducing ferroptosis may be effective treatment approaches for ovarian endometriosis.

The role of mitochondrial dynamics in the pathophysiology of endometriosis

AIM

Endometriosis is a chronic disease of reproductive age, associated with pelvic pain and infertility. Endometriotic cells adapt to changing environments such as oxidative stress and hypoxia in order to survive. However, the underlying mechanisms remain to be fully elucidated. In this review, we summarize our current understanding of the pathogenesis of endometriosis, focusing primarily on the molecular basis of energy metabolism, redox homeostasis, and mitochondrial function, and discuss perspectives on future research directions.

METHODS

Papers published up to March 31, 2023 in the PubMed and Google Scholar databases were included in this narrative literature review.

RESULTS

Mitochondria serve as a central hub sensing a multitude of physiological processes, including energy production and cellular redox homeostasis. Under hypoxia, endometriotic cells favor glycolysis and actively produce pyruvate, nicotinamide adenine dinucleotide phosphate (NADPH), and other metabolites for cell proliferation. Mitochondrial fission and fusion dynamics may regulate the phenotypic plasticity of cellular energy metabolism, that is, aerobic glycolysis or OXPHOS. Endometriotic cells have been reported to have reduced mitochondrial numbers, increased lamellar cristae, improved energy efficiency, and enhanced cell proliferation and survival. Increased mitochondrial fission and fusion turnover by hypoxic and normoxic conditions suggests an activation of mitochondrial quality control mechanisms. Recently, candidate molecules that influence mitochondrial dynamics have begun to be identified.

CONCLUSION

This review suggests that unique energy metabolism and redox homeostasis driven by mitochondrial dynamics may be linked to the pathophysiology of endometriosis. However, further studies are needed to elucidate the regulatory mechanisms of mitochondrial dynamics in endometriosis.

ITRAQ-based proteomics analysis of human ectopic endometrial stromal cells treated by Maqian essential oil

BACKGROUND

Endometriosis is a common and complex syndrome characterized by the presence of endometrial-like tissue outside the uterus. Chinese medicine has been recently found to show good efficacy in treating endometriosis. Our previous results revealed that Maqian fruit essential oil (MQEO) could inhibit the proliferation and induce apoptosis of ectopic endometrial stromal cells (EESCs), but the mechanisms remain unclear. In this study, we aim to explore the molecular mechanism of MQEO's specific effects in EESCs.

METHODS

We conducted a quantitative proteomics analysis by iTRAQ on EESCs treated with MQEO or DMSO. Then deep analysis was performed based on differentially expressed proteins, including Gene Ontology enrichment analysis, pathway enrichment analysis and protein interaction analysis. Candidate protein targets were subsequently verified by western blotting.

RESULTS

Among 6575 identified proteins, 435 proteins exhibited altered expression levels in MQEO-treated EESCs. Of these proteins, most were distributed in signal transduction as well as immune system and the most significantly altered pathway was complement and coagulation cascades. Moreover, two differentially expressed proteins (Heme oxygenase 1 and Acyl-CoA 6-desaturase) were verified and they can be potential biomarkers for endometriosis treatment.

CONCLUSIONS

Our proteomic analysis revealed distinct protein expression patterns induced by MQEO treatment in EESCs, highlighting the potential of MQEO for endometriosis treatment and biomarker discovery.

Transcriptome-wide high-throughput m6 A sequencing of differential m6 A methylation patterns in the decidual tissues from RSA patients

Recurrent spontaneous abortion (RSA) is characterized by two or more consecutive pregnancy losses in the first trimester of pregnancy, experienced by 5% of women during their reproductive age. As a complex pathological process, the etiology of RSA remains poorly understood. Recent studies have established that gene expression changes dramatically in human endometrial stromal cells (ESCs) during decidualization. N6-methyladenosine (m⁶ A) modification is the most prevalent epigenetic modification of mRNA in eukaryotic cells and it is closely related to the occurrence and development of many pathophysiological phenomena. In this study, we first confirmed that high levels of m⁶ A mRNA methylation in decidual tissues are associated with RSA. Then, we used m⁶ A-modified RNA immunoprecipitation sequence (m⁶ A-seq) and RNA sequence (RNA-seq) to identify the differentially expressed m⁶ A methylation in decidual tissues from RSA patients and identified the key genes involved in abnormal decidualization by bioinformatics analysis. Using m⁶ A-seq, we identified a total of 2169 genes with differentially expressed m⁶ A methylation, of which 735 m⁶ A hypermethylated genes and 1434 m⁶ A hypomethylated genes were identified. Further joint analysis of m⁶ A-seq and RNA-seq revealed that 133 genes were m⁶ A modified with mRNA expression. GO and KEGG analyses indicated that these unique genes were mainly enriched in environmental information processing pathways, including the cytokine-cytokine receptor interaction and PI3K-Akt signaling pathway. In summary, this study uncovered the transcriptome-wide m⁶ A modification pattern in decidual tissue of RSA, which provides a theoretical basis for further research into m⁶ A modification and new therapeutic strategies for RSA.

Emerging hallmarks of endometriosis metabolism: A promising target for the treatment of endometriosis

Endometriosis, characterized by ectopic endometrium growth in the extrauterine environment, is one of the most notable diseases of the female reproductive system. Worldwide, endometriosis affects nearly 10 % of women in their reproductive years and causes a significant decline in quality of life. Despite extensive investigations of endometriosis over the past years, the mechanisms of endometriosis pathogenesis remain unclear. In recent years, metabolic factors have increasingly been considered factors in endometriosis. There is compelling evidence regarding the progress of endometriosis in the context of severe metabolic dysfunction. Hence, the curative strategies and ongoing attempts to conquer endometriosis might start with metabolic pathways. This review focuses on metabolic mechanisms and summarizes current research progress. These findings provide valuable information for the non-intrusive diagnosis of the disease and may contribute to the understanding of the pathogenesis of endometriosis.

In Vitro Inhibitory Effects of Maqian Essential Oil against Ectopic Endometrial Stromal Cells and LPS-Induced Endometrial Epithelial Cells

Previous studies revealed that MQEO (Maqian fruits essential oil), which is extracted from the fruit of Maqian (Zanthoxylum myriacanthum var. Pubescens), had a good anti-inflammatory effect, but the effect on endometriosis in vitro remains unknown. In the present study, the inhibitory effects of MQEO against the EESCs (ectopic endometrial stromal cells) were investigated. Cells were treated with a concentration gradient (from 0.025 % to 0.15 %) of MQEO for 24 h and cell viability was detected by CCK-8. In addition, apoptotic rates were investigated using flow cytometry. The effect of MQEO on cell migration was determined by wound-healing and transwell assay. The expression of apoptosis-associated and cell adhesion-related proteins was assessed by western blotting. The transcriptional levels of IL-1, IL-6 and TNF-α were determined by Real-time qPCR. RNA-seq was used to identify the DEGs (differentially expressed genes) in MQEO-pretreated EESCs. We found that the MQEO condition dosage-dependently reduced the cell viability of EESCs. Based on flow cytometry results, the number of apoptotic cells increased significantly with dosage. The wound-healing and transwell results showed that MQEO group exhibited a significantly decreased cell motility and migration ability in comparison with the normal group. Western blotting results showed that MQEO down-regulated the expression of Bcl-2, ICAM-1 (intercellular adhesion molecule 1) and CD44, but up-regulated the cleaved caspase-3 expression in EESCs. What's more, MQEO also inhibited the LPS-induced inflammation in human EECs (endometrial epithelial cells). RNA-seq revealed that 221 DEGs were up-regulated genes and 284 DEGs were down-regulated in MQEO-pretreated EESCs. Our data uncovered the beneficial effects of MQEO in endometriosis and provided new insights into the mechanism of the effect of MQEO on EESCs, suggesting MQEO could be a promising new therapeutic agent for endometriosis.