The role of pyroptosis in inflammatory diseases

Breaking the barriers: Overcoming cancer resistance by targeting the NLRP3 inflammasome

Inflammation has a pivotal role in the initiation and progression of various cancers, contributing to crucial processes such as metastasis, angiogenesis, cell proliferation and invasion. Moreover, the release of cytokines mediated by inflammation within the tumour microenvironment (TME) has a crucial role in orchestrating these events. The activation of inflammatory caspases, facilitated by the recruitment of caspase-1, is initiated by the activation of pattern recognition receptors on the immune cell membrane. This activation results in the production of proinflammatory cytokines, including IL-1β and IL-18, and participates in diverse biological processes with significant implications. The NOD-Like Receptor Protein 3 (NLRP3) inflammasome holds a central role in innate immunity and regulates inflammation through releasing IL-1β and IL-18. Moreover, it interacts with various cellular compartments. Recently, the mechanisms underlying NLRP3 inflammasome activation have garnered considerable attention. Disruption in NLRP3 inflammasome activation has been associated with a spectrum of inflammatory diseases, encompassing diabetes, enteritis, neurodegenerative diseases, obesity and tumours. The NLRP3 impact on tumorigenesis varies across different cancer types, with contrasting roles observed. For example, colorectal cancer associated with colitis can be suppressed by NLRP3, whereas gastric and skin cancers may be promoted by its activity. This review provides comprehensive insights into the structure, biological characteristics and mechanisms of the NLRP3 inflammasome, with a specific focus on the relationship between NLRP3 and tumour-related immune responses, and TME. Furthermore, the review explores potential strategies for targeting cancers via NLRP3 inflammasome modulation. This encompasses innovative approaches, including NLRP3-based nanoparticles, gene-targeted therapy and immune checkpoint inhibitors.

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.

Targeting hepcidin in colorectal cancer triggers a TNF-dependent-gasdermin E-driven immunogenic cell death response

Interactions between colorectal cancer (CRC) cells and the noncancerous cells in the tumor microenvironment (TME) induce mechanisms for the escape of tumor cells from immune attack. Hepcidin, a peptide that controls immune cell functions, is overproduced by CRC cells. This study aimed to evaluate whether hepcidin acts as a regulator of anti-tumor immunity in CRC. Hepcidin silencing in CRC cells was followed by enhanced TNF-driven caspase-dependent cleavage of GSDM E and death. Mice engrafted with hepcidin-deficient CT26 cells developed fewer and smaller tumors than control mice as a result of the action of tumor-infiltrating CD8+ T lymphocytes and were protected from the development of tumors in a vaccination model and exhibited long-lasting tumor protection. Additionally, hepcidin deficiency enhanced the response of mice bearing CT26-derived tumors to anti-PD-1 therapy. These results suggest that targeting hepcidin in CRC cells enhances the production of TNF thereby triggering a caspase/GSDM E-driven lytic cell death with the downstream effect of boosting a robust immune response against tumor antigens.

Tamarixetin Protects Chondrocytes against IL-1β-Induced Osteoarthritis Phenotype by Inhibiting NF-κB and Activating Nrf2 Signaling

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage breakdown and chronic inflammation in joints. As the most prevalent form of arthritis, OA affects around 600 million people globally. Despite the increasing number of individuals with OA risk factors, such as aging and obesity, there is currently no effective cure for the disease. In this context, this study investigated the therapeutic effects of tamarixetin, a flavonoid with antioxidative and anti-inflammatory properties, against OA pathology and elucidated the underlying molecular mechanism. In interleukin-1β (IL-1β)-treated chondrocytes, tamarixetin inhibited the OA phenotypes, restoring cell viability and chondrogenic properties while reducing hypertrophic differentiation and dedifferentiation. Tamarixetin alleviated oxidative stress via the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway activation and inhibited mitogen-activated protein kinase and nuclear factor-κB (NF-κB). Furthermore, tamarixetin attenuated pyroptosis, a programmed cell death caused by excessive inflammation, by suppressing inflammasome activation. We confirmed that the chondroprotective effects of tamarixetin are mediated by the concurrent upregulation of Nrf2 signaling and downregulation of NF-κB signaling, which are key players in balancing antioxidative and inflammatory responses. Overall, our study demonstrated that tamarixetin possesses chondroprotective properties by alleviating IL-1β-induced cellular stress in chondrocytes, suggesting its therapeutic potential to relieve OA phenotype.

Icaritin Exerts Anti-Cancer Effects through Modulating Pyroptosis and Immune Activities in Hepatocellular Carcinoma

Icaritin (ICT), a natural compound extracted from the dried leaves of the genus Epimedium, possesses antitumor and immunomodulatory properties. However, the mechanisms through which ICT modulates pyroptosis and immune response in hepatocellular carcinoma (HCC) remain unclear. This study demonstrated that ICT exhibits pyroptosis-inducing and anti-hepatocarcinoma effects. Specifically, the caspase1-GSDMD and caspase3-GSDME pathways were found to be involved in ICT-triggered pyroptosis. Furthermore, ICT promoted pyroptosis in co-cultivation of HepG2 cells and macrophages, regulating the release of inflammatory cytokines and the transformation of macrophages into a proinflammatory phenotype. In the Hepa1-6+Luc liver cancer model, ICT treatment significantly increased the expression of cleaved-caspase1, cleaved-caspase3, and granzyme B, modulated cytokine secretion, and stimulated CD8+ T cell infiltration, resulting in a reduction in tumor growth. In conclusion, the findings in this research suggested that ICT may modulate cell pyroptosis in HCC and subsequently regulate the immune microenvironment of the tumor. These observations may expand the understanding of the pharmacological mechanism of ICT, as well as the therapy of liver cancer.

Ginsenoside Rb1 ameliorates apical periodontitis via suppressing macrophage pyroptosis

OBJECTIVES

The objectives of current study were to investigate the role and related mechanism of Ginsenoside Rb1 (GRb1) on regulating apical periodontitis (AP) prognosis.

MATERIALS AND METHODS

Clinical specimens were used to determine the involvement of calcium overload-induced macrophage pyroptosis in periapical tissues. Next, a calcium ion-chelating agent (BAPTA-AM) was applied to detect the suppression of intracellular calcium overload in macrophage pyroptosis. Then, network pharmacology, western blot (WB) analysis, and Fluo-4 calcium assay were conducted to explore the role of GRb1 on intracellular calcium overload. To gain a better understanding of GRb1 in calcium overload-induced macrophage pyroptosis linked AP, GRb1-treated AP models were established.

RESULTS

We discovered clinically and experimentally that calcium overload-dependent macrophage pyroptosis is involved in AP pathogenesis, and reducing calcium overload greatly decreased macrophage pyroptosis in an AP cell model. Next, based on GRb1's inhibitory role in aberrant intracellular calcium accumulation, we discovered that GRb1 alleviates AP by suppressing calcium-dependent macrophage pyroptosis in both in vitro and in vivo models.

CONCLUSIONS

GRb1 is an effective therapeutic strategy to rescue the periapical tissues from inflammation due to its anti-pyroptosis function. Thus, the present study supports further investigation of GRb1 as an adjuvant therapy for AP.

Overview of Systemic Autoinflammatory Diseases

Systemic autoinflammatory diseases (SAID) are a growing family of disorders of the innate immune system. Over the years, there have been changes in the definition, classification and nomenclature of SAID as new syndromes and pathophysiologic mechanisms continue to be described. Recognizing the clinical manifestations of SAID is important for their early diagnosis and management. The field continues to advance with potential new therapies underway.

A novel role of AIM2 inflammasome-mediated pyroptosis in radiofrequency ablation of hepatocellular carcinoma

INTRODUCTION AND OBJECTIVES

The absence of melanoma 2 (AIM2) protein triggers the activation of the inflammasome cascade. It is unclear whether AIM2 plays a role in hepatocellular carcinoma (HCC) and radiofrequency ablation (RFA), which uses radiofrequency waves to treat tumors. In this study, we investigated if RFA could induce pyroptosis, also called cell inflammatory necrosis, in HCC through AIM2-inflammasome signaling in vivo and in vitro.

MATERIALS AND METHODS

BALB/c nude mice were used to generate HepG2 or SMMC-7721 cell-derived tumor xenografts. HCC cells with knockdown or overexpression of AIM2 were created using short hairpin RNA (shRNA) and expression vector transfection, respectively, for functional and mechanistic studies. Downstream effects were examined using flow cytometry, qRT-PCR, ELISAs, and other molecular assays.

RESULTS

RFA significantly suppressed tumor growth in HCC cell xenografts. Flow cytometry analysis revealed that RFA could induce pyroptosis. Furthermore, AIM2, NLRP3, caspase-1, γ-H2AX, and DNA-PKc had significantly greater expression levels in liver tissues from mice treated with RFA compared with those of the controls. Additionally, interleukin (IL)-1β and IL-18 expression levels were significantly higher in the HCC cell-derived xenograft mice treated with RFA compared with those without RFA. Notably, a significantly greater effect was achieved in the RFA complete ablation group versus the partial ablation group. Knockdown or overexpression of AIM2 in HCC cells demonstrated that AIM2 exerted a role in RFA-induced pyroptosis.

CONCLUSIONS

RFA can suppress HCC tumor growth by inducing pyroptosis via AIM2. Therefore, therapeutically intervening with AIM2-mediated inflammasome signaling may help improve RFA treatment outcomes for HCC patients.

[Research Progress on the Role of GSDME-mediated Pyroptosis in the Treatment of Lung Cancer]

Lung cancer causes a significant threat to human health. Despite considerable advancements in the treatment technologies in recent years, the five-year survival rate for lung cancer patients remains low. In this context, the discovery of pyroptosis, a unique cell death mechanism, offers a novel perspective for exploring new pathways of lung cancer treatment. Particularly, the role of gasdermin E (GSDME) in the process of pyroptosis reveals its tremendous potential in lung cancer therapy. Recent studies have made considerable progress in understanding the role of GSDME-mediated pyroptosis in lung cancer growth, the lung cancer microenvironment, and the effect of GSDME methylation on lung cancer treatment. This paper summarizes these research advancements and analyzes the potential and possible side effects of GSDME-mediated pyroptosis in lung cancer therapy, aiming to provide a theoretical foundation for developing more effective strategies for lung cancer treatment.
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The impact of AIM2 inflammasome-induced pyroptosis on acute gouty arthritis and asymptomatic hyperuricemia patients

Objective

This study aimed to evaluate the role of absent in melanoma 2 (AIM2) inflammasome-mediated pyroptosis in the pathogenesis of acute gouty arthritis (AGA) and asymptomatic hyperuricemia(AHU).

Methods

A cohort of 30 AGA patients, 30 AHU individuals, and 30 healthy controls (HC) was assembled. Demographic and biochemical data, along with blood samples, were collected. Serum double-stranded DNA (dsDNA) levels were quantified using a fluorescent assay. Transcriptomic and proteomic analysis of AIM2, Caspase-1, GSDMD, IL-1β, and IL-18 in peripheral blood mononuclear cells was performed using qRT-PCR and Western blot. Enzyme-linked immunosorbent assay (ELISA) was employed to measure serum IL-1β and IL-18. Spearman correlation analysis was utilized to assess relationships between variables.

Results

Both AGA and AHU groups demonstrated elevated metabolic indicators and serum levels of dsDNA, IL-1β, and IL-18 compared to the HC group. AGA patients exhibited higher inflammatory markers than the AHU group. In the AGA group, there was a significant increase in the mRNA and protein levels of AIM2, Caspase-1, GSDMD, IL-1β, and IL-18 (P<0.05 to P<0.001). The AHU group showed higher AIM2, Caspase-1, GSDMD, and IL-18 mRNA levels than the HC group (P<0.001 to P<0.01), with a non-significant increase in AIM2, GSDMD, and IL-1β proteins (P>0.05). In contrast, Caspase-1 and IL-18 proteins were significantly higher in the AHU group (P<0.05). Notable correlations were observed between AIM2 protein expression and levels of Caspase-1 and GSDMD in both AGA and AHU groups. In the AGA group, AIM2 protein correlated with IL-1β, but not in the AHU group. The AIM2 protein in the AHU group was positively associated with IL-18, with no such correlation in the AGA group.

Conclusion

AIM2 inflammasome may play a role in the inflammatory processes of AGA and AHU and that its activation may be related to the pyroptosis pathway.

Metabolism-inflammasome crosstalk shapes innate and adaptive immunity

Inflammasomes are a central component of innate immunity and play a vital role in regulating innate immune response. Activation of inflammasomes is also indispensable for adaptive immunity, modulating the development and response of adaptive immunity. Recently, increasing studies have shown that metabolic alterations and adaptations strongly influence and regulate the differentiation and function of the immune system. In this review, we will take a holistic view of how inflammasomes bridge innate and adaptive (especially T cell) immunity and how inflammasomes crosstalk with metabolic signals during the immune responses. And, special attention will be paid to the metabolic control of inflammasome-mediated interactions between innate and adaptive immunity in disease. Understanding the metabolic regulatory functions of inflammasomes would provide new insights into future research directions in this area and may help to identify potential targets for inflammasome-associated diseases and broaden therapeutic avenues.

B355252 Suppresses LPS-Induced Neuroinflammation in the Mouse Brain

B355252 is a small molecular compound known for potentiating neural growth factor and protecting against neuronal cell death induced by glutamate in vitro and cerebral ischemia in vivo. However, its other biological functions remain unclear. This study aims to investigate whether B355252 suppresses neuroinflammatory responses and cell death in the brain. C57BL/6j mice were intraperitoneally injected with a single dosage of lipopolysaccharide (LPS, 1 mg/kg) to induce inflammation. B355252 (1 mg/kg) intervention was started two days prior to the LPS injection. The animal behavioral changes were assessed pre- and post-LPS injections. The animal brains were harvested at 4 and 24 h post-LPS injection, and histological, biochemical, and cytokine array outcomes were examined. Results showed that B355252 improved LPS-induced behavioral deterioration, mitigated brain tissue damage, and suppressed the activation of microglial and astrocytes. Furthermore, B355252 reduced the protein levels of key pyroptotic markers TLR4, NLRP3, and caspase-1 and inhibited the LPS-induced increases in IL-1β, IL-18, and cytokines. In conclusion, B355252 demonstrates a potent anti-neuroinflammatory effect in vivo, suggesting that its potential therapeutic value warrants further investigation.

Study on network pharmacology of Ginkgo biloba extract against ischaemic stroke mechanism and establishment of UPLC-MS/MS methods for simultaneous determination of 19 main active components

INTRODUCTION

Ginkgo biloba extract (GBE) is an effective substance from traditional Chinese medicine (TCM) G. biloba for treating ischaemic stroke (IS). However, its active ingredients and mechanism of action remain unclear.

OBJECTIVES

This study aimed to reveal the potential active component group and possible anti-IS mechanism of GBE.

MATERIALS AND METHODS

The network pharmacology method was used to reveal the possible anti-IS mechanism of these active ingredients in GBE. An ultra-high-performance liquid chromatography triple quadrupole electrospray tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous detection of the active ingredients of GBE.

RESULTS

The active components of GBE anti-IS were screened by literature integration. Network pharmacology results showed that the anti-IS effect of GBE is achieved through key active components such as protocatechuic acid, bilobalide, ginkgolide A, and so on. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the possible anti-IS mechanism of GBE is regulating the PI3K-Akt signalling pathway and other signal pathways closely related to inflammatory response and apoptosis regulation combined with AKT1, MAPK, TNF, ALB, CASP3, and other protein targets. Nineteen main constituents in seven batches of GBE were successfully analysed using the established UPLC-MS/MS method, and the results showed that the content of protocatechuic acid, gallic acid, ginkgolide A, and so forth was relatively high, which was consistent with network pharmacology results, indicating that these ingredients may be the key active anti-IS ingredients of GBE.

CONCLUSION

This study revealed the key active components and the anti-IS mechanism of GBE. It also provided a simple and sensitive method for the quality control of related preparations.

Extracellular vesicles of Weizmannia coagulans lilac-01 reduced cell death of primary microglia and increased mitochondrial content in dermal fibroblasts in vitro

We investigated the properties of extracellular vesicles from the probiotic Weizmannia coagulans lilac-01 (Lilac-01EVs). The phospholipids in the Lilac-01EV membrane were phosphatidylglycerol and mitochondria-specific cardiolipin. We found that applying Lilac-01EVs to primary rat microglia in vitro resulted in a reduction in primary microglial cell death (P < .05). Lilac-01EVs, which contain cardiolipin and phosphatidylglycerol, may have the potential to inhibit cell death in primary microglia. The addition of Lilac-01EVs to senescent human dermal fibroblasts suggested that Lilac-01 EVs increase the mitochondrial content without affecting their membrane potential in these cells.

The NLRP3 inflammasome in viral infection (Review)

The interplay between pathogen and host determines the immune response during viral infection. The Nod‑like receptor (NLR) protein 3 inflammasome is a multiprotein complex that induces the activation of inflammatory caspases and the release of IL‑1β, which play an important role in the innate immune responses. In the present review, the mechanisms of the NLR family pyrin domain containing 3 inflammasome activation and its dysregulation in viral infection were addressed.