A novel mechanism regulating pyroptosis-induced fibrosis in endometriosis via lnc-MALAT1/miR-141-3p/NLRP3 pathway†

CHS-Ⅳa activates the IGF1R/PI3K signal pathway with inhibited pyroptosis of endometrial stromal cells and progress of endometriosis

ETHNOPHARMACOLOGICAL RELEVANCE

Chikusetsusaponin IVa (CHS IVa) as a natural extract from the Panax japonicus (T.Nees) C.A.Mey (P. japonicus), can regulate the immune responses, such as anti-inflammation, which have been applied in treating various diseases. It is still unclear, nevertheless, whether the CHS IVa can target-able treat endometriosis (EMs) and what the possible mechanism would be.

PURPOSE OF THE STUDY

This work aims to investigate the possible mechanism and the impact of CHS IVa on EMs.

MATERIALS AND METHODS

The EMs models were established in mice by autologous transplantation or chemicals (lipopolysaccharide and adenosine triphosphate), inducing the pyroptotic endometrial stromal cells. Then the CHS IVa was used to treat the EMs mice. The therapeutic impact of CHS IVa was assessed by hematoxylin-eosin staining, immunofluorescent staining, western blot (WB), and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results of immunofluorescence and WB indicated that pyroptosis indicators, including Gasdermin-D (GSDMD), Caspase-1, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), and interleukin (IL)-1β, were substantially expressed in the ectopic endometrial lesions of EMs mice. The ELISA results showed that the abdominal cavity of EMs mice had higher concentrations of IL-1β, IL-6, and TNF-α than the non-EMs animals (control group). As shown in the molecule docking experiments, CHS IVa exhibited high binding affinity with GSDMD, IL-1β, Caspase-1, and NLRP3. Moreover, after treatment with CHS IVa, the expression levels of GSDMD, IL-1β, Caspase-1, and NLRP3 decreased in the EMs mice. Meanwhile, the expression level of pain-related proteins, such as pro-nerve growth factor (pro-NGF) and transient receptor potential vanilloid-1 (TRPV1), was inhibited via the treatment of CHS IVa. According to the antibody chip analysis, the insulin-like growth factor 1 receptor/phosphatidylinositide 3-kinases (IGF1R/PI3K) signal pathway was essential to the CHS IVa's treatment of EMs. Finally, according to the WB experiments, after the treatment with CHS-Ⅳa, the expression of IGF1R, PI3K, and related phosphorylated proteins increased compared to the mice in lipopolysaccharide + adenosine triphosphate (LPS + ATP) groups.

CONCLUSION

CHS IVa can activate the IGF1R/PI3K signal pathway, inhibit the pyroptosis of endometrial stromal cells, and relieve the inflammation and EMs.

The role of fibrosis in endometriosis: a systematic review

BACKGROUND

Fibrosis is an important pathological feature of endometriotic lesions of all subtypes. Fibrosis is present in and around endometriotic lesions, and a central role in its development is played by myofibroblasts, which are cells derived mainly after epithelial-to-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT). Transforming growth factor-β (TGF-β) has a key role in this myofibroblastic differentiation. Myofibroblasts deposit extracellular matrix (ECM) and have contracting abilities, leading to a stiff micro-environment. These aspects are hypothesized to be involved in the origin of endometriosis-associated pain. Additionally, similarities between endometriosis-related fibrosis and other fibrotic diseases, such as systemic sclerosis or lung fibrosis, indicate that targeting fibrosis could be a potential therapeutic strategy for non-hormonal therapy for endometriosis.

OBJECTIVE AND RATIONALE

This review aims to summarize the current knowledge and to highlight the knowledge gaps about the role of fibrosis in endometriosis. A comprehensive literature overview about the role of fibrosis in endometriosis can improve the efficiency of fibrosis-oriented research in endometriosis.

SEARCH METHODS

A systematic literature search was performed in three biomedical databases using search terms for 'endometriosis', 'fibrosis', 'myofibroblasts', 'collagen', and 'α-smooth muscle actin'. Original studies were included if they reported about fibrosis and endometriosis. Both preclinical in vitro and animal studies, as well as research concerning human subjects were included.

OUTCOMES

Our search yielded 3441 results, of which 142 studies were included in this review. Most studies scored a high to moderate risk of bias according to the bias assessment tools. The studies were divided in three categories: human observational studies, experimental studies with human-derived material, and animal studies. The observational studies showed details about the histologic appearance of fibrosis in endometriosis and the co-occurrence of nerves and immune cells in lesions. The in vitro studies identified several pro-fibrotic pathways in relation to endometriosis. The animal studies mainly assessed the effect of potential therapeutic strategies to halt or regress fibrosis, for example targeting platelets or mast cells.

WIDER IMPLICATIONS

This review shows the central role of fibrosis and its main cellular driver, the myofibroblast, in endometriosis. Platelets and TGF-β have a pivotal role in pro-fibrotic signaling. The presence of nerves and neuropeptides is closely associated with fibrosis in endometriotic lesions, and is likely a cause of endometriosis-associated pain. The process of fibrotic development after EMT and FMT shares characteristics with other fibrotic diseases, so exploring similarities in endometriosis with known processes in diseases like systemic sclerosis, idiopathic pulmonary fibrosis or liver cirrhosis is relevant and a promising direction to explore new treatment strategies. The close relationship with nerves appears rather unique for endometriosis-related fibrosis and is not observed in other fibrotic diseases.

REGISTRATION NUMBER

N/A.

Apparent lncRNAs involvement in pathogenesis of endometriosis

Endometriosis is an estrogen-dependent, debilitating gynecologic disease impacting millions of women globally. One of the main characteristics of this benign condition is the presence of endometrial-like tissue outside the uterus, causing dysmenorrhea, chronic pelvic pain, and infertility. However, despite many reports on the origin and molecular pathogenesis of endometriosis, the etiology of this disease has not been fully explored yet. Recently, significant attention has been paid to long noncoding RNAs (lncRNAs). Numerous studies focused on exploring the association between lncRNAs and the progression of various human diseases. LncRNAs function as competing endogenous RNAs (ceRNAs) interacting with microRNAs as a “sponge” to regulate cell functions. According to multiple studies, lncRNAs seem to have the potential as markers for diagnosing, and monitoring progression and staging in endometriosis. In this review, we summarized the lncRNAs that were found to influence the pathogenesis of endometriosis. Furthermore, we tried to assess its potential in the process of endometriosis transition from benign through atypical forms, up to EAOC (Endometriosis Associated Ovarian Cancer).

Blocking GATA6 Alleviates Pyroptosis and Inhibits Abdominal Wall Endometriosis Lesion Growth Through Inactivating the PI3K/AKT Pathway

Endometriosis is a benign gynecological disorder characterized by the abnormal presence of endometrium-like cells, referred to as ectopic tissue, located outside the uterine cavity. Beyond the abnormal proliferation of endometrium-like tissues within and beyond the pelvic cavity, compelling scientific evidence underscores the crucial involvement of the NOD-like receptor NLRP3 inflammasome and pyroptosis in the pathogenesis of EMS. Our investigation has revealed a striking upregulation of the endogenous protein GATA-binding protein 6 (GATA6) in abdominal wall EMS. Notably, the knockdown of GATA6 significantly impaired the viability and migratory potential of primary ectopic endometrial stromal cells (EESCs) while also inhibiting crucial markers of pyroptosis, such as NLRP3, the gasdermin D N-terminal fragment (GSDMD-N), and reactive oxygen species (ROS) levels within these cells. Delving deeper into the underlying mechanisms, we discovered that suppressing GATA6 mitigated the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in EESCs. The administration of 740 Y-P, an agonist of the PI3K/AKT pathway, mitigated the inhibitive actions of GATA6 knockdown on EESCs' growth, migration, and pyroptosis, highlighting the intricate crosstalk between GATA6 and this intricate signaling cascade. In vivo experiments corroborated these findings, demonstrating that reduced GATA6 expression effectively restrained the growth of endometrial lesions and concurrently suppressed pyroptosis, accompanied by a dampening of PI3K/AKT signaling within these lesions. In summary, our study underscores the pivotal role of GATA6 in modulating the growth and pyroptosis of abdominal wall EMS through its regulation of the PI3K/AKT signaling pathway. Silencing GATA6 emerges as a promising approach to alleviate pyroptosis and potentially offers a novel therapeutic angle for managing abdominal wall EMS.

Role of Pyroptosis in Endometrial Cancer and Its Therapeutic Regulation

Pyroptosis is an inflammatory cell death induced by inflammasomes that release several pro-inflammatory mediators such as interleukin-18 (IL-18) and interleukin-1β (IL-1β). Pyroptosis, a type of programmed cell death, has recently received increased interest both as a therapeutic and immunological mechanism. Numerous studies have provided substantial evidence supporting the involvement of inflammasomes and pyroptosis in a variety of pathological conditions including cancers, nerve damage, inflammatory diseases and metabolic conditions. Researchers have demonstrated that dysregulation of pyroptosis and inflammasomes contribute to the progression of endometriosis and gynecological malignancies. Current research also indicates that inflammasome and pyroptosis-dependent signaling pathways may further induce the progression of endometrial cancer (EC). More specifically, dysregulation of NLR family pyrin domain 3 (NLRP3) and caspase-1-dependent pyroptosis play a contributory role in the pathogenesis and development of EC. Therefore, pyroptosis-regulated protein gasdermin D (GSDMD) may be an independent prognostic biomarker for the detection of EC. This review presents the molecular mechanisms of pyroptosis-dependent signaling pathways and their contributory role and function in advancing EC. Moreover, this review offers new insights into potential future applications and innovative approaches in utilizing pyroptosis to develop effective anti-cancer therapies.

Impaired bone morphogenetic protein (BMP) signaling pathways disrupt decidualization in endometriosis

Endometriosis is linked to increased infertility and pregnancy complications due to defective endometrial decidualization. We hypothesized that identification of altered signaling pathways during decidualization could identify the underlying cause of infertility and pregnancy complications. Our study reveals that transforming growth factor β (TGFβ) pathways are impaired in the endometrium of individuals with endometriosis, leading to defective decidualization. Through detailed transcriptomic analyses, we discovered abnormalities in TGFβ signaling pathways and key regulators, such as SMAD4, in the endometrium of affected individuals. We also observed compromised activity of bone morphogenetic proteins (BMP), a subset of the TGFβ family, that control endometrial receptivity. Using 3-dimensional models of endometrial stromal and epithelial assembloids, we showed that exogenous BMP2 improved decidual marker expression in individuals with endometriosis. Our findings reveal dysfunction of BMP/SMAD signaling in the endometrium of individuals with endometriosis, explaining decidualization defects and subsequent pregnancy complications in these individuals.

Regulated Cell Death in Endometriosis

Regulated cell death (RCD) represents a distinct mode of cell demise, differing from accidental cell death (ACD), characterized by specific signaling cascades orchestrated by diverse biomolecules. The regular process of cell death plays a crucial role in upholding internal homeostasis, acting as a safeguard against biological or chemical damage. Nonetheless, specific programmed cell deaths have the potential to activate an immune-inflammatory response, potentially contributing to diseases by enlisting immune cells and releasing pro-inflammatory factors. Endometriosis, a prevalent gynecological ailment, remains incompletely understood despite substantial progress in unraveling associated signaling pathways. Its complexity is intricately tied to the dysregulation of inflammatory immune responses, with various RCD processes such as apoptosis, autophagic cell death, pyroptosis, and ferroptosis implicated in its development. Notably, limited research explores the association between endometriosis and specific RCD pathways like pyroptosis and cuproptosis. The exploration of regulated cell death in the context of endometriosis holds tremendous potential for further advancements. This article thoroughly reviews the molecular mechanisms governed by regulated cell death and their implications for endometriosis. A comprehensive understanding of the regulated cell death mechanism in endometriosis has the potential to catalyze the development of promising therapeutic strategies and chart the course for future research directions in the field.

Role of the NLRP3 inflammasome in gynecological disease

The NLR family pyrin domain containing 3 (NLRP3) inflammasome is involved in the innate immune system and is a three-part macromolecular complex comprising the NLRP3 protein, apoptosis-associated speck-like protein containing a CARD (ASC) and the cysteine protease pro-caspase-1. When the NLRP3 inflammasome is activated, it can produce interleukin (IL)- 1β and IL-18 and eventually lead to inflammatory cell pyroptosis. Related studies have demonstrated that the NLRP3 inflammasome can induce an immune response and is related to the occurrence and development of gynecological diseases, such as endometriosis, polycystic ovary syndrome and breast cancer. NLRP3 inflammasome inhibitors are beneficial for maintaining cellular homeostasis and tissue health and have been found effective in targeting some gynecological diseases. However, excessive inhibitor concentrations have been found to cause adverse effects. Therefore, proper control of NLRP3 inflammasome activity is critical. This paper summarizes the structure and function of the NLRP3 inflammasome and highlights the therapeutic potential of targeting it in gynecological diseases, such as endometriosis, polycystic ovary syndrome and breast cancer The application of NLRP3 inflammasome inhibitors is also discussed.

Impaired bone morphogenetic protein signaling pathways disrupt decidualization in endometriosis

It is hypothesized that impaired endometrial decidualization contributes to decreased fertility in individuals with endometriosis. To identify the molecular defects that underpin defective decidualization in endometriosis, we subjected endometrial stromal cells from individuals with or without endometriosis to time course in vitro decidualization with estradiol, progesterone, and 8-bromo-cyclic-AMP (EPC) for 2, 4, 6, or 8 days. Transcriptomic profiling identified differences in key pathways between the two groups, including defective bone morphogenetic protein (BMP)/SMAD4 signaling (ID2, ID3, FST), oxidate stress response (NFE2L2, ALOX15, SLC40A1), and retinoic acid signaling pathways (RARRES, RARB, ALDH1B1). Genome-wide binding analyses identified an altered genomic distribution of SMAD4 and H3K27Ac in the decidualized stromal cells from individuals without endometriosis relative to those with endometriosis, with target genes enriched in pathways related to signaling by transforming growth factor β (TGFβ), neurotrophic tyrosine kinase receptors (NTRK), and nerve growth factor (NGF)-stimulated transcription. We found that direct SMAD1/5/4 target genes control FOXO, PI3K/AKT, and progesterone-mediated signaling in decidualizing cells and that BMP2 supplementation in endometriosis patient-derived assembloids elevated the expression of decidualization markers. In summary, transcriptomic and genome-wide binding analyses of patient-derived endometrial cells and assembloids identified that a functional BMP/SMAD1/5/4 signaling program is crucial for engaging decidualization.