Pyroptosis: host cell death and inflammation

Exploring the efficacy and constraints of platinum nanoparticles as adjuvant therapy in silicosis management

Silicosis represents a formidable occupational lung pathology precipitated by the pulmonary assimilation of respirable crystalline silica particulates. This condition engenders a cascade of cellular oxidative stress via the activation of bioavailable silica, culminating in the generation of reactive oxygen species (ROS). Such oxidative mechanisms lead to irrevocable pulmonary impairment. Contemporary scholarly examinations have underscored the substantial antioxidative efficacy of platinum nanoparticles (PtNPs), postulating their utility as an adjunct therapeutic modality in silicosis management. The physicochemical interaction between PtNPs and silica demonstrates a propensity for adsorption, thereby facilitating the amelioration and subsequent pulmonary clearance of silica aggregates. In addition to their detoxifying attributes, PtNPs exhibit pronounced anti-inflammatory and antioxidative activities, which can neutralize ROS and inhibit macrophage-mediated inflammatory processes. Such attributes are instrumental in attenuating inflammatory responses and forestalling subsequent lung tissue damage. This discourse delineates the interplay between ROS and PtNPs, the pathogenesis of silicosis and its progression to pulmonary fibrosis, and critically evaluates the potential adjunct role of PtNPs in the therapeutic landscape of silicosis, alongside a contemplation of the inherent limitations associated with PtNPs application in this context.

Intracellular Staphylococcus aureus in osteoblasts and osteocytes and its impact on bone homeostasis during osteomyelitis

Osteomyelitis is a severe infection of bone tissue that can lead to bone loss and even osteonecrosis. This condition is mostly caused by Gram-positive bacteria, with Staphylococcus aureus being the most common etiological agent. Among the pathophysiological mechanisms involved in osteomyelitis, the ability of S. aureus to be internalized by osteoblasts or osteocytes and to survive within these cells, is particularly noteworthy. Infected osteoblasts and osteocytes not only serve as reservoirs in chronic cases of osteomyelitis but also play an active role in the osteoimmunology process, notably by producing mediators that promote the bone resorption activity of osteoclasts, thereby disrupting bone homeostasis. The present review explores both historical and recent literature on the internalization of S. aureus by osteoblasts and osteocytes, its intracellular behavior following internalization, and its mechanisms for inducing cell death. Additionally, it examines how S. aureus affects bone formation activity and promotes the production of inflammatory and pro-osteoclastic mediators. This review aims to highlight the limitations of current findings and outline key questions for future investigations.

The inflammasome adaptor pycard is essential for immunity against Mycobacterium marinum infection in adult zebrafish

Inflammasomes regulate the host response to intracellular pathogens including mycobacteria. We have previously shown that the course of Mycobacterium marinum infection in adult zebrafish (Danio rerio) mimics the course of tuberculosis in human. To investigate the role of the inflammasome adaptor pycard in zebrafish M. marinum infection, we produced two zebrafish knockout mutant lines for the pycard gene with CRISPR/Cas9 mutagenesis. Although the zebrafish larvae lacking pycard developed normally and had unaltered resistance against M. marinum, the loss of pycard led to impaired survival and increased bacterial burden in the adult zebrafish. Based on histology, immune cell aggregates, granulomas, were larger in pycard-deficient fish than in wild-type controls. Transcriptome analysis with RNA sequencing of a zebrafish haematopoietic tissue, kidney, suggested a role for pycard in neutrophil-mediated defence, haematopoiesis and myelopoiesis during infection. Transcriptome analysis of fluorescently labelled, pycard-deficient kidney neutrophils identified genes that are associated with compromised resistance, supporting the importance of pycard for neutrophil-mediated immunity against M. marinum. Our results indicate that pycard is essential for resistance against mycobacteria in adult zebrafish.

Particulate matter 2.5 stimulates pyroptosis and necroptosis via the p38 MAPK/Akt/NF-κB signaling pathway in human corneal epithelial cells

Particulate matter 2.5 (PM2.5) exposure poses significant health risks, particularly to the eyes. This study aimed to investigate the cytotoxic effects of PM2.5 on human corneal epithelial cells (HCECs) and to elucidate the mechanisms involved in pyroptosis and necroptosis. HCECs were exposed to PM2.5, and cytotoxicity, reactive oxygen species (ROS) levels, and the expression of pyroptosis- and necroptosis-related proteins were assessed. The roles of nuclear factor-kappa B (NF-κB) and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome signaling pathways were also investigated. Exposure to PM2.5 caused a dose-dependent decrease in cell viability, accompanied by significant NLRP3 inflammasome activation, leading to pyroptosis and the release of pro-inflammatory cytokines. Enhanced ROS generation and mitochondrial dysfunction have also been observed, along with indicators of necroptosis, such as increased levels of mixed-lineage kinase domain-like proteins. Importantly, activation of the NF-κB signaling pathway was crucial for these responses. The suppression of p38 mitogen-activated protein kinase (MAPK) and activation of protein kinase B (Akt) using pharmacological modulators SB203580 and SC79, respectively, significantly reduced PM2.5-mediated cellular damage. These findings indicate that p38 MAPK inhibition and Akt activation are key regulatory mechanisms that help attenuate the deleterious effects of PM2.5 on HCECs. In conclusion, our findings offer new insights into the mechanisms by which PM2.5 induces pyroptosis and necroptosis in HCECs, especially by activating the NLRP3 inflammasome and NF-κB signaling pathways. The critical regulatory roles of p38 MAPK and Akt underscore their potential as therapeutic targets to alleviate PM-induced ocular damage.

Identification of pyroptosis-related gene S100A12 as a potential diagnostic biomarker for sepsis through bioinformatics analysis and machine learning

Sepsis is a non-discriminatory inflammatory reaction that can result in a diverse array of organ dysfunctions, which can be fatal. Pyroptosis is a programmed mechanism of cell death that is distinguishable from apoptosis and other forms of cellular demise. However, the role of pyroptosis in sepsis remains to be further explored. In this study, by employing a combination of the difference analysis, WGCNA, Friends' analysis, and machine learning, the central gene S100A12 was successfully identified. S100A12 demonstrated superb diagnostic capabilities in both the integrated and external validation datasets. Furthermore, significant disparities were observed in the levels of monocytes, eosinophils, and neutrophils between sepsis patients and the control group, as per the findings of immune infiltration analysis. The aforementioned immune infiltrating cells exhibited an increase in expression levels among patients diagnosed with sepsis and were found to be significantly and positively associated with S100A12 expression. The results of the single-cell analysis indicated a significant expression of S100A12 in both neutrophils and monocytes, which was in complete alignment with the outcomes of immune infiltration. In summary, the pyroptosis-related gene S100A12 represents a potential biomarker for the diagnosis and treatment of sepsis.

Mechanisms of LPS-induced toxicity in endothelial cells and the protective role of geniposidic acid

Vascular inflammation and oxidative stress are critical pathogenic factors in cardiovascular diseases. Lipopolysaccharide (LPS)-induced endothelial cytotoxicity, driven by oxidative stress and inflammation, remains incompletely understood. This study highlights the molecular mechanisms underlying LPS toxicity, focusing on the ROS/JNK/NLRP3 signaling axis. LPS disrupts mitochondrial function, increases ROS accumulation, activates JNK phosphorylation, and induces NLRP3 inflammasome activation, culminating in pyroptosis through caspase-1-mediated GSDMD cleavage. Mechanistic studies with the JNK inhibitor SP600125 confirmed the critical role of the ROS/JNK/NLRP3 pathway in LPS-induced endothelial damage. Additionally, PGC-1α, a key regulator of mitochondrial homeostasis, was identified as a protective factor suppressed by LPS, exacerbating ROS overproduction and inflammasome activation. To validate these findings, geniposidic acid (GPA), a natural antioxidant and anti-inflammatory compound, was employed. GPA effectively reduced ROS levels, inhibited JNK activation, and suppressed pyroptosis, supporting its utility as a chemical tool to confirm the pivotal role of ROS/JNK/NLRP3 signaling. This study elucidates the intricate interplay between oxidative stress, mitochondrial dysfunction, and pyroptosis, providing a comprehensive framework for addressing inflammation-driven vascular damage.

Two-photon photosensitizer for specific targeting and induction of tumor pyroptosis to elicit systemic immunity-boosting anti-tumor therapy

Photodynamic therapy (PDT) has garnered increasing attention in cancer treatment due to its precise spatiotemporal selectivity and non-invasive nature. However, several challenges, including the inability of photosensitizers to discriminate between tumor and healthy tissues, as well as the limited tissue penetration depth of light sources, impede its broader application. To surmount these impediments, our research introduces a two-photon photosensitizer (TPSS) that specifically targets tumor overexpressing carbonic anhydrase IX (CA IX), thereby exhibiting exceptional specificity for tumor cells. Under two-photon laser stimulation, TPSS generates a large amount of reactive oxygen species (ROS), inducing cell pyroptosis and subsequently triggering a strong anti-tumor immune response. Additionally, proteomics analysis provides compelling evidence to elucidate the anti-tumor mechanism of TPSS in vivo. Through comprehensive immune assessments, TPSS under two-photon laser irradiation effectively activates both the innate and adaptive immune systems, efficiently suppressing the proliferation of distant metastatic tumors, underscoring its considerable therapeutic potential. Collectively, this study provides a viable strategy to overcome the limitations of PDT, highlighting the prospects of two-photon excitation photosensitizers.

Dipeptidyl peptidase 9 (DPP9) depletion from hepatocytes in experimental primary liver cancer

Dipeptidyl peptidase 9 (DPP9) is an indispensable intracellular protease. Among its many molecular functions is suppression of the NLRP1 inflammasome. Inhibitors targeting all four proteases of the DPP4 family, including DPP9, can reduce tumour burden, including in mouse liver. To explore hepatocyte DPP9 in experimental hepatocellular carcinoma (HCC), we generated hepatocyte-specific DPP9-KO mice by crossing albumin-Cre mice with DPP9 floxed mice and treated sequentially with diethylnitrosamine, then with thioacetamide combined with an atherogenic high-fat diet until 28 weeks of age. DPP9-KO mice had less body, liver and subcutaneous adipose tissue mass, lower fasting plasma glucose and fewer small macroscopic liver nodules compared to DPP9-WT control mice. However, there were no differences in the total number of macroscopic liver nodules, or of microscopic tumour burden, inflammation, fibrosis or steatosis. Consistent with the known function of DPP9 to suppress NLRP1 activation, activated caspase-1 protein and inflammation markers Nfkbib, Cxcl10 and Ccl5 were elevated in DPP9-KO liver. The tumour suppressor protein p53 was increased and the autophagy proteins beclin1, LC3B and p62 were altered. In conclusion, hepatocyte-specific DPP9 gene deletion in experimental primary liver cancer improved energy metabolism and may reduce liver cancer initiation, via mechanisms that may include increased autophagy and tumour suppression.

Ferroptosis-activating metabolite acrolein antagonizes necroptosis and anti-cancer therapeutics

Dysregulated cell death leading to uncontrolled cell proliferation is a hallmark of cancer. Chemotherapy-induced cell death is critical for the success of cancer treatment but this process is impaired by metabolic byproducts. How these byproducts interfere with anti-cancer therapy is unclear. Here, we show that the metabolic byproduct acrolein derived from polyamines, tobacco smoke or fuel combustion, induces ferroptosis independently of ZBP1, while suppressing necroptosis in cancer cells by inhibiting the oligomerization of the necroptosis effector MLKL. Loss of the enzyme SAT1, which contributes to intracellular acrolein production, sensitizes cells to necroptosis. In mice, administration of an acrolein-trapping agent relieves necroptosis blockade and enhances the anti-tumor efficacy of the chemotherapeutic drug cyclophosphamide. Human patients with cancer coupled with a higher cell death activity but a lower expression of genes controlling polyamine metabolism exhibit improved survival. These findings highlight that the removal of metabolic byproducts improves the success of certain chemotherapies.

High uric acid exacerbates nonalcoholic steatohepatitis through NLRP3 inflammasome and Gasdermin D-mediated pyroptosis

Hyperuricemia is independently associated with an increased risk of nonalcoholic steatohepatitis (NASH), but the underlying mechanisms responsible for this association remain unclear. We first analyzed the association between intrahepatic UA levels and gasdermin D (GSDMD)-mediated pyroptosis in vivo and in vitro. We subsequently generated hepatic-specific glucose transporter 9 (GLUT9)-knockout mice and GSDMD knockout (GSDMD-/-) mice to explore the role of intrahepatic UA in GSDMD-induced pyroptosis in NASH. We found that high intrahepatic UA levels were positively related to GSDMD-mediated pyroptosis in NASH mice. The inhibition of hepatic UA production by allopurinol alleviated hepatic inflammation and GSDMD-mediated pyroptosis in NASH mice. Hepatic-specific knockout of Glut9 significantly decreased intrahepatic UA levels, attenuated NOD-like receptor family pyrin domain containing 3 (NLRP3)-Caspase-1-GSDMD-mediated pyroptosis in hepatocytes, and ameliorated hepatic inflammation and fibrosis in different mouse models of NASH. Further experiments revealed that inhibiting the NLRP3/Caspase-1/GSDMD pathway obviously blocked UA-induced pyroptosis and inflammation in hepatocytes. Additionally, GSDMD deficiency markedly reversed hepatic inflammation and fibrosis in NASH mice. In conclusion, our results showed that high UA could induce NLRP3-Caspase1-GSDMD-mediated pyroptosis, thereby aggravating NASH in mice.

Molecular Insight into the Role of Vitamin D in Immune-Mediated Inflammatory Diseases

In the last decades, it has become increasingly evident that the role of vitamin D extends beyond the regulation of calcium homeostasis and the maintenance of bone health. A significant extraskeletal function of vitamin D is its role in modulating the immune system, particularly highlighted in the context of immune-mediated inflammatory diseases, where correlations between vitamin D status and genetic variations in the vitamin D receptor have been observed about the incidence and severity of these conditions. Additionally, different studies have reported the existence of immunomodulatory effects of vitamin D, particularly the effects of vitamin D on dendritic cell function, maturation, cytokine production, and antigen presentation, and that its deficiency may be associated with a sub-inflammatory state. In this sense, different clinical trials have been conducted to assess the therapeutic efficacy of vitamin D in different immune-mediated inflammatory disorders, including asthma, atopic dermatitis (AD), rheumatoid arthritis (RA), psoriasis, thyroid diseases, infectious diseases, and systemic lupus erythematosus (SLE). This review will provide a comprehensive overview of the current understanding of the molecular mechanisms underlying vitamin D's immunomodulatory properties, its role, and innovative therapeutic applications in patients with immune-mediated inflammatory diseases.

Engineering pyroptotic vesicles as personalized cancer vaccines

Tumour vaccines are designed to stimulate the host's immune system against existing tumours or tumour recurrence. However, individual differences, tumour heterogeneity and side effects hinder the applications of current tumour vaccines and require the development of personalized cancer vaccines. To overcome these challenges, we engineered pyroptotic vesicles-extracellular vesicles formed during tumour cell pyroptosis-as a tumour vaccine platform. The extracted pyroptotic vesicles possess abundant tumour antigens and potent immune-stimulating ability and, loaded into a biocompatible hydrogel, they can be implanted into post-surgical tumour cavities to prevent tumour recurrence. The pyroptotic-vesicle-based vaccine outperforms both exosome- and apoptotic-body-based vaccines in inhibiting tumour recurrence and metastasis in different post-surgical mouse models. Mechanistic studies reveal that the pyroptotic-vesicle-based vaccine could stimulate robust antigen-specific dendritic cell and T cell immune responses against both artificial OVA antigens and cancer neoantigens. In sum, our vaccine platform can be tailored to stimulate robust antitumour immune responses for treating individual cancer patients.

Effects of Adipose-Derived Mesenchymal Stem Cell-Secretome on Pyroptosis of Laparoscopic Hepatic Ischemia Reperfusion Injury in a Porcine Model

Extensive research has been conducted on mesenchymal stem cells (MSCs) regarding their ability to modify the immune response and reduce tissue damage. Many researchers have found that the regulatory capacity of MSCs primarily comes from their secretome. As a result, there has been much interest in utilizing "cell-free" therapies as alternatives to stem cell treatments. In this study, the secretome from adipose mesenchymal stem cells (ADSC-secretome) was extracted and injected into minipigs with established liver injury models. Blood and liver tissue samples were obtained prior to the procedure, as well as on days 1, 3, and 7 after surgery. It was found that ADSC-secretome effectively suppressed the synthesis of the NOD-like receptor protein 3 (NLRP3) inflammasome, leading to a downregulation of gasdermin-D (GSDMD) expression, and demonstrated a more prominent anti-pyroptosis effect compared to ADSCs. Furthermore, ADSC-secretome inhibited the high mobility group box 1 (HMGB1)/toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) inflammatory pathway. In summary, both ADSC-secretome and ADSCs inhibited pyroptosis in right hemihepatic ischemia-reperfusion combined with left hemihepatectomy injury, and ADSC-secretome exhibited a stronger therapeutic effect. ADSC-secretome exerted these therapeutic effects through the inhibition of the HMGB1/TLR4/NF-κB inflammatory pathway. In the future, "cell-free" therapy is expected to replace cell-based methods.

Targeting cholesterol-driven pyroptosis: a promising strategy for the prevention and treatment of atherosclerosis

Funding Pyroptosis is a type of programmed cell death (PCD) pathway distinguished by inflammation. It is activated by specific inflammasomes. Once activated, it causes the physical breakdown of the cell, along with the discharge of pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin-18 (IL-18). Abundant evidence has demonstrated the existence of pyroptotic cell death within atherosclerotic plaques, which has significance for the development of atherosclerosis (AS). As a result, pyroptosis has become a new and important topic in cardiovascular disease (CVD) research. Cholesterol, it is recognized to have a connection with inflammation, exerts a crucial function in the development process of AS, and has been linked to the initiation of pyroptosis. This review aims to briefly summarize the fundamental aspects of pyroptosis and the influence of cholesterol-related inflammation in AS. Additionally, this review will explore potential therapeutic approaches based on pyroptosis that could be utilized for the prevention and treatment of AS.

Evodiamine inhibits NLRP3 inflammasome-mediated microglial pyroptosis and promotes remyelination via SLC2A4-regulated autophagy

BACKGROUND

Activation of the NLRP3 inflammasome triggers pyroptosis, a pro-inflammatory type of cell death, in multiple sclerosis (MS). Evodiamine (EVO) possesses anti-inflammatory and neuroprotective properties; however, its potential molecular and signaling pathways in MS remain to be elucidated. This study aimed to explore the therapeutic potential of EVO for remyelination in MS and elucidated its underlying mechanisms.

METHODS

We utilized cuprizon (CPZ)/experimental autoimmune encephalomyelitis (EAE)-induced demyelinated mice and lipopolysaccharide+adenosine triphosphate (LPS+ATP)-induced pyroptosis of BV2 cells to investigate the potential of EVO in MS treatment. Various analyses were conducted, including rotarod fatigue test, RNA sequence, luxol fast blue, molecular docking, SPR, immunoblotting, qRT-PCR, immunofluorescence, and transmission electron microscopy, to analysis the targets and signaling pathways involved in EVO treatment.

RESULTS

EVO emerged as a promising remyelination agent in the CPZ/EAE demyelination models, acting through SLC2A4. Regarding its mechanism, EVO inhibited NLRP3 inflammasome-mediated microglial pyroptosis through SLC2A4 regulation of autophagy during demyelinating disease, but this change was reversed by SLC2A4 inhibitor PGF2α in vivo. Additionally, EVO inhibited LPS+ATP-induced pyroptosis of BV2 cells by preventing NLRP3 inflammasome activity and cleavage of the pyroptosis executive protein gasdermin D. It also promoted autophagy and inhibited NLRP3 inflammasome-mediated pyroptosis in BV2 cells via SLC2A4. Furthermore, an autophagy inhibitor 3-methyladenine reversed the inhibitory effect of EVO on NLRP3 inflammasome-mediated pyroptosis in BV2 cells.

CONCLUSION

The present study demonstrated that EVO inhibits NLRP3 inflammasome-mediated microglial pyroptosis and promotes remyelination via SLC2A4-regulated autophagy during demyelinating disease, which suggests EVO as a promising drug candidate for the treatment of MS.

Bone marrow microenvironment in myelodysplastic neoplasms: insights into pathogenesis, biomarkers, and therapeutic targets

Myelodysplastic neoplasms (MDS) represent a heterogeneous group of malignant hematopoietic stem and progenitor cell (HSPC) disorders characterized by cytopenia, ineffective hematopoiesis, as well as the potential to progress to acute myeloid leukemia (AML). The pathogenesis of MDS is influenced by intrinsic factors, such as genetic insults, and extrinsic factors, including altered bone marrow microenvironment (BMM) composition and architecture. BMM is reprogrammed in MDS, initially to prevent the development of the disease but eventually to provide a survival advantage to dysplastic cells. Recently, inflammation or age-related inflammation in the bone marrow has been identified as a key pathogenic mechanism for MDS. Inflammatory signals trigger stress hematopoiesis, causing HSPCs to emerge from quiescence and resulting in MDS development. A better understanding of the role of the BMM in the pathogenesis of MDS has opened up new avenues for improving diagnosis, prognosis, and treatment of the disease. This article provides a comprehensive review of the current knowledge regarding the significance of the BMM to MDS pathophysiology and highlights recent advances in developing innovative therapies.

MiR-214-3p targets RIPK1 to regulate pyroptosis and vascular endothelial function in diabetic ketoacidosis: mechanistic insights

BACKGROUNDS

MicroRNAs (miRNAs) exhibit essential effects on the occurrence and progress of diabetes mellitus (DM) and DM complications. However, the detailed role of miRNAs in diabetic ketoacidosis (DKA) is rarely reported.

OBJECTIVE

The present work focused on the role of miR-214-3p on DKA and the detailed mechanisms.

METHODS

First, macrophages were isolated from the venous blood of DKA patients, and ELISA was employed to determine the serum levels of inflammatory factors, serum macrophage numbers by flow cytometry, and macrophage miR-214-3p expression levels determined through PCR.. Subsequently, miR-214-3p was overexpressed in macrophages to detect macrophage proliferation, apoptosis, pyroptosis and inflammatory factor secretion. A dual luciferase reporter was used to analyze the downstream targets of miR-214-3p. Finally, macrophages overexpressing miR-214-3p were co-cultured with Human Umbilical Vein Endothelial Cells (HUVECs) to detect the effects of HUVECs proliferation, apoptosis, and angiogenesis and barrier function.

RESULTS

First, there is an elevation in serum inflammatory factors and a reduction in miR-214-3p levels in serum macrophages among DKA patients, and overexpression of miR-214-3p by macrophages promotes their proliferation, inhibits their pyroptosis, and reduces the secretion of inflammatory factors. In addition, Receptor-interacting protein kinase 1 (RIPK1) was predicted to be a target of miR-214-3p. Finally, co-culture of macrophages overexpressing miR-214-3p with HUVECs promoted HUVECs proliferation, inhibited apoptosis, and facilitated the tube-forming ability and repaired the barrier function of HUVECs.

CONCLUSION

MiR-214-3p targets RIPK1 and regulates vascular endothelial function in diabetic ketoacidosis, suggesting that miR-214-3p has the potential to be a novel marker for the treatment of DKA.

Multifunctional Fluorescent Probes for Profiling Cys, Hcy, GSH, and SO₂: Illuminating Their Dynamics in Apoptosis and Ferroptosis

The ability to perform simultaneous fluorescence imaging of multiple targets is essential, providing crucial multi-parametric information necessary for understanding complex biological interactions and processes. In this study, TBC, a novel multi-signal fluorescent probe is presented, crafted for simultaneous differentiation and in situ real-time monitoring of homocysteine (Hcy), cysteine (Cys), sulfur dioxide (SO2), and glutathione (GSH), illuminating the dynamic metabolic status of endogenous reactive sulfur species. TBC achieves an ultrahigh signal-to-background ratio, enabling wash-free direct fluorescence imaging of the dynamics and distribution of these entities in living cells and zebrafish. Notably, TBC has revealed distinctive dynamic metabolic features of Hcy/Cys/SO2/GSH during apoptosis and ferroptosis. This innovative probe acts as a key tool for unraveling the conversion networks of multiple reactive sulfur species and assessing the impact of metabolic oscillations during programmed cell death and the progression of diverse diseases, effectively uncovering concurrent biochemical dynamics in various biological settings and cell death events.

Abalone Haliotis discus caspase 8 is an apoptosis effector and a pyroptosis activator

In mammals, caspase 8 (CASP8) is a well-known initiator caspase of apoptosis. In invertebrates, the function of CASP8 is poorly understood. Herein, we examined the function of abalone Haliotis discus CASP8 (HdCASP8). Compared to mammalian CASP8, HdCASP8 possesses the conserved DED and CASc domains but also has an extra death domain (DD). HdCASP8 induced marked apoptosis of HEK293T cells without activating CASP3/6/7. Consistently, HdCASP8 did not cleave H. discus CASP3 (HdCASP3). HdCASP8 exhibited CASP3/6-like cleavage specificity and cleaved the apoptotic substrate DFF45. HdCASP3 is known to activate abalone pyroptosis by cleaving H. discus gasdermin E (HdGSDME) at two sites, DQVD and DEID. In the present work, HdCASP8 was found to interact with HdGSDME at its C-terminal region and induce pyroptosis by cleaving HdGSDME at DQVD but not at DEID. During bacterial infection, the expressions of HdCASP8 and HdGSDME were significantly upregulated in multiple tissues of abalone in a time-dependent manner. Together these results indicate that, most likely owing to its unique structural feature, HdCASP8 differs from the classical CASP8 by acting as an apoptosis/pyroptosis-regulating CASP3 and from the classical CASP3 in certain aspects of substrate specificity. These findings provide new insights into CASP8-mediated programmed cell death in invertebrates.

Intestinal 8 gingerol attenuates TBI-induced neuroinflammation by inhibiting microglia NLRP3 inflammasome activation in a PINK1/Parkin-dependent manner

BACKGROUND

traumatic brain injury (TBI) is irreversible brain damage, leading to inflammation and cognitive dysfunction. Microglia involved in the inflammatory response after TBI. The gut microbiota, known as the body's "second brain," regulates neurogenesis and immune responses, but its precise role in regulating TBI remains unclear.

PURPOSE

to investigate the effect of gut microbiota and metabolites disorder on TBI injury.

STUDY DESIGN

16SrRNA and metabolomics compared gut microbiota and metabolites in sham group and TBI group, then proved that the differential metabolite 8-gingerol (8G) alleviated the microglia neuroinflammatory response after TBI.

METHODS

fecal microbiota transplantation explored the role of dysbiosis in TBI. LC/MS detected the content of 8-gingerol in cecum, blood, and brain. HE, Nissl, Tunel staining and mNSS score evaluated brain injury. Western blot and immunofluorescence detected the expression of inflammasome-related proteins and mitophagy-related proteins in brain tissue and BV2 cells. RNA sequencing analyzed the molecular mechanism of 8-gingerol.

RESULT

rats transplanted with TBI feces had worse brain injury and neurological deficits than those with normal feces. 16SrRNA and metabolomics found that TBI caused dysbiosis and decreased 8-gingerol level, leading to severe neuroinflammation. Mechanistically, 8-gingerol inhibited NLRP3 inflammasome by promoting PINK1-Parkin mediated mitophagy in microglia. Inhibition of Parkin, through either small interfering RNA or the inhibitor 3MA reversed the inhibitory effect of 8-gingerol on NLRP3 by blocking mitophagy. BV2 cells transcriptome showed that 8-gingerol significantly increased the expression of autophagy factor Wipi1, and small interfering RNA of Wipi1 abolished the effect of 8-gingerol on promoting mitophagy and the inhibitory effect on NLRP3.

CONCLUSION

our findings shed light on the pivotal role of gut microbes in TBI, and identify 8 gingerol as an important anti-inflammatory compound during TBI.

Unraveling the mechanisms of NINJ1-mediated plasma membrane rupture in lytic cell death and related diseases

Plasma membrane rupture (PMR), the ultimate event during lytic cell death, releases damage-associated molecular patterns (DAMPs) that trigger inflammation and immune responses in the development of various diseases. Recent years have witnessed significant advances in understanding the PMR mediated by ninjurin1 (NINJ1) in different lytic cell death processes. NINJ1 oligomerizes and ruptures the membrane in pyroptosis and other lytic cell death, participating in the pathogenesis of multiple diseases. Although the membrane-permeabilizing function of NINJ1 is well recognized, the role of NINJ1 in different types of lytic cell death and its impact on multiple disease processes have yet to be fully elucidated. This review summarizes the latest advances in the mechanisms of NINJ1-mediated PMR, discusses the membrane-inducing activity of NINJ1 in different lytic cell death, explains the implications of NINJ1 in lytic cell death-related diseases, and lists the inhibitory strategies for NINJ1. We expect to provide new insights into targeting NINJ1 to suppress lytic cell death for therapeutic benefit, which may become a new strategy to control inflammatory cell lysis-related diseases.

A bibliometric analysis of the literature published on autophagy, ferroptosis, necroptosis, and pyroptosis in cardiovascular disease from 2009 to 2023

Background

Programmed cell death (PCD) plays a pivotal role in the development and progression of cardiovascular disease (CVD), which remains the leading cause of mortality worldwide. Among the various types of PCD, autophagy, ferroptosis, necroptosis, and pyroptosis have garnered increasing attention due to their involvement in inflammation, oxidative stress, and cardiomyocyte survival. Although numerous studies have explored the underlying mechanisms of these pathways, their therapeutic potential in clinical practice remains limited. With the rapid growth of publications in this field, a comprehensive understanding of research trends and influential studies is essential to guide future investigations. This study aimed to characterize the progress and research hotspots of autophagy in CVD, ferroptosis in CVD, necroptosis in CVD, and pyroptosis in CVD through a bibliometric analysis to provide a comprehensive overview of PCD in CVD.

Methods

Publications from January 1, 2009, to December 31, 2023, were analyzed using the "bibliometrix" R package to assess research output, key contributors, and influential journals in each field.

Results

For the topic of autophagy in CVD, 6,426 articles published by 4,891 institutions from 90 countries/regions were retrieved. For the topic of necroptosis in CVD, 393 articles from 616 organizations in 53 countries/regions were retrieved. For the topic of pyroptosis in CVD, 640 publications from 754 institutions in 48 countries/regions were retrieved. Finally, for the topic of ferroptosis in CVD, 687 articles from 827 institutions in 49 countries/regions were retrieved. Key contributors included Adriana A (22 publications on necroptosis), Ge J, and Ye B (8 publications each on pyroptosis), and Ren J (lead contributor in autophagy and ferroptosis, with 120 and 10 publications, respectively). The most frequently co-cited journals were Cell, Nature, Free Radical Biology and Medicine, and the Journal of Biological Chemistry.

Conclusions

This bibliometric analysis highlights the growing interest in PCD in CVD research, with autophagy and pyroptosis being the central themes. Future studies should examine therapeutic strategies targeting ferroptosis and necroptosis to improve CVD treatment. The findings provide a roadmap for researchers to navigate emerging research hotspots and foster interdisciplinary collaboration.

Inflammasome signaling in astrocytes modulates hippocampal plasticity

Emerging evidence indicates that a baseline level of controlled innate immune signaling is required to support proper brain function. However, little is known about the function of most innate immune pathways in homeostatic neurobiology. Here, we report a role for astrocyte-dependent inflammasome signaling in regulating hippocampal plasticity. Inflammasomes are multiprotein complexes that promote caspase-1-mediated interleukin (IL)-1 and IL-18 production in response to pathogens and tissue damage. We observed that inflammasome complex formation was regularly detected under homeostasis in hippocampal astrocytes and that its assembly is dynamically regulated in response to learning and regional activity. Conditional ablation of caspase-1 in astrocytes limited hyperexcitability in an acute seizure model and impacted hippocampal plasticity via modulation of synaptic protein density, neuronal activity, and perineuronal net coverage. Caspase-1 and IL-18 regulated hippocampal IL-33 production and related plasticity. These findings reveal a homeostatic function for astrocyte inflammasome activity in regulating hippocampal physiology in health and disease.

Salivary Biomarkers of Inflammasome Activation in Unstable Periodontitis: A Case-Control Study

The objective of this study was to investigate the complex network of inflammasome-related biomarkers (NOD-like receptor thermal protein domain associated protein 3 [NLRP3], caspase-1, interleukin [IL]-1β, IL-18, and IL-37) in unstable periodontitis by examining the salivary concentrations of these specific biomarkers and correlating them with periodontal parameters.The design of this study was an observational case-control study. A salivary sample was collected from periodontally healthy patients (n = 40) and unstable periodontitis patients (n = 40). Full-mouth clinical periodontal parameters were recorded (plaque index, bleeding on probing, periodontal pocket depth, and clinical attachment loss). Enzyme-linked immunosorbent assay analyzed NLRP3, caspase-1, IL-1β, IL-18, and IL-37 salivary levels.The normality of the data was tested using the Shapiro-Wilk test. Mean, standard deviation, and percentages were used for data description. An independent sample t-test, Mann-Whitney U test, and chi-square test were used to compare the two groups with a p-value of < 0.05. Spearman's correlation analysis was conducted to examine the relationships between variables.In saliva samples, NLRP3, caspase-1, IL-1β, and IL-18 were the highest in the periodontitis group (p < 0.005), while IL-37 was highest in the healthy group (p < 0.005). There was significant (p < 0.012) negative weak correlation (-0.395) between IL-37 and IL-1β, and significant (p < 0.003) negative moderate correlation (-0.455) between IL-37 and IL-18 in the healthy group. A significant (0.031) positive weak correlation (0.342) was found between the salivary IL-37 and NLRP3, and a significant (p < 0.001) negative moderate correlation (-0.508) was found between salivary IL-37 and IL-1β, in the periodontitis group.The NLRP3 inflammasomes and their cytokines (caspase-1, IL-1β, and IL-18) significantly promote periodontal inflammation and tissue destruction. In contrast, IL-37 acts as an anti-inflammatory cytokine, inhibiting the activity of the NLRP3 inflammasome and reducing excessive inflammation. This interplay highlights the potential of targeting NLRP3 and enhancing IL-37 as a therapeutic approach for the treatment of periodontal disease.

Pyroptosis in sepsis-associated acute kidney injury: mechanisms and therapeutic perspectives

Sepsis-associated acute kidney injury (S-AKI) is a severe complication characterized by high morbidity and mortality, driven by multi-organ dysfunction. Recent evidence suggests that pyroptosis, a form of programmed cell death distinct from apoptosis and necrosis, plays a critical role in the pathophysiology of S-AKI. This review examines the mechanisms of pyroptosis, focusing on inflammasome activation (e.g., NLRP3), caspase-mediated processes, and the role of Gasdermin D in renal tubular damage. We also discuss the contributions of inflammatory mediators, oxidative stress, and potential therapeutic strategies targeting pyroptosis, including inflammasome inhibitors, caspase inhibitors, and anti-inflammatory therapies. Lastly, we highlight the clinical implications and challenges in translating these findings into effective treatments, underscoring the need for personalized medicine approaches in managing S-AKI.

A Pyroptosis-Related LncRNA Signature for Predicting Prognosis, Immune Features and Drug Sensitivity in Ovarian Cancer

Background

Multiple studies have suggested that lncRNAs and pyroptosis play important roles in ovarian cancer (OC). However, the function of pyroptosis-related lncRNAs (PRLs) in OC is not fully understood.

Methods

Clinical information and RNA-seq data of OC patients (n = 379) were collected from TCGA database. Pearson correlation analysis and univariate Cox analysis were performed to identify prognostic PRLs, respectively. LASSO-COX regression was utilized to construct a prognostic PRLs signature. Kaplan-Meier (K-M) curve analyses and receiver operating characteristics (ROC) were used to evaluate the prognostic prediction of the signature. The association between risk score and tumor microenvironment infiltration, immunotherapy response and chemotherapy sensitivity were also analyzed. In addition, the function of TYMSOS on OC and pyroptosis was experimentally confirmed in cell lines.

Results

Firstly, 32 prognostic PRLs were identified, and a novel prognostic PRLs signature was constructed and validated. Surprisingly, the prognostic PRLs signature could solidly predict the clinical outcome of patients with OC and patients with high-risk score shown a short overall survival. GSEA results suggested that the RPLs were mainly enriched in the inflammatory response pathway, p53 pathway, TGF-β signaling and TNFα signaling. Besides, our results demonstrated that the risk score was significantly associated with patients with immune infiltration, immunotherapy response and the sensitivity of veliparib and metformin. Furthermore, the oncogene effect of TYMSOS on OC by inhibiting pyroptosis was verified by experiments.

Conclusion

This study found that the prognostic PRLs signature may serve as an efficient biomarker in predicting the prognosis, tumor microenvironment infiltration, and sensitivity of chemotherapeutic agents. TYMSOS is a potential biomarker in OC, and it might promote tumor progression by inhibiting pyroptosis.

Pyroptosis of pulmonary fibroblasts and macrophages through NLRC4 inflammasome leads to acute respiratory failure

The NAIP/NLRC4 inflammasome plays a pivotal role in the defense against bacterial infections, with its in vivo physiological function primarily recognized as driving inflammation in immune cells. Acute lung injury (ALI) is a leading cause of mortality in sepsis. In this study, we identify that the NAIP/NLRC4 inflammasome is highly expressed in both macrophages and pulmonary fibroblasts and that pyroptosis of these cells plays a critical role in lung injury. Mice challenged with gram-negative bacteria or flagellin developed lethal lung injury, characterized by reduced blood oxygen saturation, disrupted lung barrier function, and escalated inflammation. Flagellin-induced lung injury was protected in caspase-1 or GSDMD-deficient mice. These findings enhance our understanding of the NAIP/NLRC4 inflammasome's (patho)physiological function and highlight the significant role of inflammasome activation and pyroptosis in ALI during sepsis.

Ferroptosis in immune chaos: Unraveling its impact on disease and therapeutic potential

Since its introduction in 2012, ferroptosis has garnered significant attention from researchers over the past decade. Unlike autophagy and apoptosis, ferroptosis is an atypical iron-dependent programmed cell death that falls under necrosis. It is regulated by various cellular metabolic and signaling processes, which encompass amino acid, lipid, iron, and mitochondrial metabolism. The initiation of ferroptosis occurs through iron-dependent phospholipid peroxidation. Notably, ferroptosis exhibits a dual effect and is associated with various diseases. A significant challenge lies in managing autoimmune disorders with unknown origins that stem from the reactivation of the immune system. Two contributing factors to autoimmunity are the aberrant stimulation of cell death and the inadequate clearance of dead cells, which can expose or release intracellular components that activate the immune response. Ferroptosis is distinct from other forms of cell death, such as apoptosis, necroptosis, autophagy, and pyroptosis, due to its unique morphological, biochemical, and genetic characteristics and specific relationship with cellular iron levels. Recent studies indicate that immune cells can both induce and undergo ferroptosis. To better understand how ferroptosis influences immune responses and its imbalance in disease, a molecular understanding of the relationship between ferroptosis and immunity is essential. Consequently, further research is needed to develop immunotherapeutics that target ferroptosis. This review primarily focuses on the role of ferroptosis in immune-related disorders.

TLR4-mediated endoplasmic reticulum stress regulates pyroptosis in macrophages infected with the Bacillus Calmette-Guérin mycobacterial

Tuberculosis results from Mycobacterium tuberculosis (Mtb) infection. Immune responses controlled by Toll-like receptor 4 (TLR4) are closely associated with the host response to pathogens, including Mtb. NLRP3 inflammasome-mediated pyroptosis forms a significant part of the inflammatory response during Mtb infection, and endoplasmic reticulum stress (ERS) is implicated in the activation of the NLRP3 inflammasome. Here, the function of TLR4 in macrophage pyroptosis induced by infection with the Bacillus Calmette-Guérin (BCG) mycobacterial strain was investigated. It was found that infection with BCG activated TLR4 signaling, induced ERS and subsequent NLRP3 inflammasome activation, leading to pyroptosis in mouse lung tissues. The TLR4 inhibitor TAK 242 inhibited the ERS onset, NLRP3 inflammasome stimulation, and pyroptosis, while the ERS inhibitor TUDCA blocked both inflammasome activation and pyroptosis, and the NLRP3 inhibitor MCC950 specifically inhibited pyroptosis. Furthermore, TAK 242, TUDCA, and MCC950 all exacerbated lung injury caused by BCG infection and promoted BCG survival. Similarly, after in BCG-infected THP-1 macrophages, TLR4 signaling was found to mediate NLRP3 inflammasome activation through ERS, thereby inducing pyroptosis. In summary, BCG infection leads to macrophage pyroptosis via the TLR4/ERS/NLRP3 inflammasome signaling axis, providing new insights for further research into the pathogenesis and treatment of tuberculosis.

Decoding NLRP3 Inflammasome Activation in Alzheimer's Disease: A Focus on Receptor Dynamics

Alzheimer's disease (AD) is a leading neurodegenerative disorder marked by progressive cognitive decline and significant neuropsychiatric disturbances. Neuroinflammation, mediated by the NLRP3 inflammasome, is increasingly recognized as a critical factor in AD pathogenesis. The NLRP3 inflammasome, a crucial component of the innate immune system, is activated in response to both pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). In AD, amyloid-beta (Aβ) plaques and tau aggregates act as DAMPs, triggering NLRP3 inflammasome activation in microglia and astrocytes. This activation leads to the production of pro-inflammatory cytokines IL-1β and IL-18, contributing to chronic neuroinflammation and neuronal death. This review explores the intricate mechanisms involved in NLRP3 activation, with a particular focus on TREM-2, Msn Kinase MINK, NF-κB, Toll-like receptors, and P2X7 receptors. Understanding these mechanisms offers insight into the multifaceted regulation of the NLRP3 inflammasome and its impact on AD pathology. By elucidating the roles of TREM-2, MINK1, NF-κB, TLRs, and P2X7 receptors, this review highlights potential therapeutic targets for modulating NLRP3 activity. Targeting these pathways could offer novel strategies for mitigating neuroinflammation and slowing the progression of AD. The interplay between these receptors and signaling pathways underscores the complexity of NLRP3 inflammasome regulation and its significance in AD, providing a foundation for future research aimed at developing effective therapeutic interventions.

The entrenchment of NLRP3 inflammasomes in autoimmune disease-related inflammation

Autoinflammation and autoimmunity are almost "opposite" phenomena characterized by chronic activation of the immune system, 'innate' in the first and 'adaptive' in the second, leading to inflammation of several tissues with specific protean effectors of tissue damage. The mechanism of involvement of multiprotein complexes called 'inflammasomes' within autoimmune pictures, differently from autoinflammatory conditions, is yet undeciphered. In this review we provide a comprehensive overview on NLRP3 inflammasome contribution into the pathogenesis of some autoimmune diseases. In response to autoantibodies against nucleic acids or tissue-specific antigens the NLRP3 inflammasome is activated within dendritic cells and macrophages of patients with systemic lupus erythematosus. Crucial is NLRP3 inflammasome to amplify tissue inflammation with interleukin-1 overexpression and matrix metalloproteinase production at the joint level in rheumatoid arthritis. A deregulated NLRP3 inflammasome activation occurs in the serous acini of salivary and lacrimal glands prone to Sjogren's syndrome, but also in the inflammatory process involving endothelial cells, leucocyte recruitment, and platelet plugging of vasculitides. Furthermore, organ-specific autoimmune diseases such as thyroiditis and hepatitis may display hyperactive NLRP3 inflammasomes at the level of resident immune cells within thyroid or liver, respectively. Therefore, it is not unexpected that preclinical studies have shown how specific inflammasome inhibitors may significantly overthrow the severity of different autoimmune diseases and slow down their trend towards an ominous progression. Specific markers of inflammasome activation could also reveal subclinical inflammatory components escaping conventional diagnostic approaches or improve monitoring of autoimmune diseases and personalizing their treatment.

Neuroprotective role of morin hydrate on 3-nitropropionic acid-elicited huntington's disease: in vivo investigation of RIPK1/RIPK3/MLKL necroptosis signaling pathway

BACKGROUND

Huntington's disease (HD) is a rare dominantly inheritable autosomal neurodegenerative disease with unclear pathophysiological pathways. In neurodegenerative disorders, including HD, necroptosis plays a significant role in neuronal death. Morin hydrate (MH), a natural bioactive flavonoid, has various pharmacological properties via orchestrating neuroinflammation, apoptosis, and necroptosis. Up to now, there is no extant data on the impact of MH on the necroptotic pathway in HD.

AIM

This research aimed to scrutinize the effect of MH on neurodegeneration initiated by 3-nitropropionic acid (3-NP) administration in rats via modulating necroptosis and apoptosis signaling pathways and compare it with necrosulfonamide (NSA) as a necroptosis inhibitor.

METHODS

HD was triggered in male wistar rats by intraperitoneal injection of 3-NP (10 mg/kg/day) for 14 days. Intraperitoneal injection of MH (20 mg/kg/day, i.p.) or NSA (1.65 mg/kg/day, i.p.) an hour prior to 3-NP administration for 14 days. At the end of study, rats were weighed, and their locomotor activity was assessed via grip strength and open field tests. Striata of rats were investigated histologically and immunohistochemically by evaluation the expression levels of glial fibrillary acidic protein (GFAP). Striatal tumor necrosis factor-alpha (TNF-α), caspase 3, and 8 levels were quantified through the ELISA technique, while striatal expression of necroptosis-associated proteins; phosphorylated form of receptor interacting protein kinase 1/3(p-RIPK1, p-RIPK3) and phosphorylated form of mixed lineage kinase domain-like protein (p-MLKL) were assessed by the Western blot technique. Striatal succinate dehydrogenase (SDH) activity was assayed colorimetrically. Finally, gene enrichment analysis using ShinyGO was employed.

RESULTS

MH and NSA significantly mitigated body weight loss and ameliorated locomotor deterioration, besides reversing histological abnormalities in the striatum of rats. Intriguingly, MH exerted similar effects on specific biomarkers and molecular signals as NSA. MH and NSA inhibited neuroinflammation, apoptosis, and necroptosis by significantly decreasing the striatal (TNF-α), caspase 3, and necroptosis-associated proteins (P-RIPK1, P-RIPK3, and P-MLKL) levels. Besides, MH and NSA also decreased striatal GFAP and increased SDH activity. Gene enrichment analysis revealed a significant interaction between genes. Together, MH exerts a neuroprotective action on 3-NP-elicited HD rats via reducing neuroinflammation, apoptosis, and necroptosis. This study highlights MH as a potential protection against HD, calling for further research to confirm its neuroprotective effects.

Manipulation of cancer cell pyroptosis for therapeutic approaches: challenges and opportunities

Remarkable advances have been achieved following discoveries that gasdermins are the executioners of pyroptosis. The pyroptotic process consists a subcellular permeabilization phase and a cell lysis phase, the latter of which is irreversible. Besides immune cells, pyroptosis has also been observed in cancer cells, which exhibit distinct mechanisms compared to canonical immune cell pyroptosis. Although chronic cancer cell pyroptosis fuels tumor growth, intense pyroptotic cell death in tumor cells enhances anticancer immunity by promoting killer lymphocytes infiltration. Triggering pyroptosis in cancer cells is emerging as a promising strategy for cancer treatment. In this review, we introduce the process of cancer cell pyroptosis and its role in antitumor immunity, discuss the translation of these insights into therapies, and highlight current challenges and opportunities in the investigation of cancer cell pyroptosis.

Kaempferol inhibits cardiomyocyte pyroptosis via promoting O-GlcNAcylation of GSDME and improved acute myocardial infarction

Acute myocardial infarction (AMI) is a leading fatal cardiovascular disease and poses a major threat to human health. Pyroptosis, an inflammation-related programmed cell death, plays a critical role in the progression of AMI. Kaempferol is a natural flavonoid compound with a variety of pharmacological effects, which exerts a significant cardioprotective function. The role of O-GlcNAcylation, a post-translation modification, has received attention in diseases including AMI. In this research, we explored the therapeutic potential of Kaempferol to AMI due to its well-known cardioprotective effect, including its antioxidant and anti-inflammatory properties. Hypoxia/reoxygenation (H/R) model was adopted to provoke myocardial injury and AMI mice model was established. Our findings indicated that H/R lessened cell viability and contributed to the release of LDH, IL-1β and IL-18, cell pyroptosis rate, and the expression of NLRP3, active caspase 1 and GSDMD-N-terminal domain (GSDMD-N). Kaempferol mitigated myocardial damage caused by H/R through repressing cell pyroptosis. Besides, we discovered that Kaempferol restored the levels of O-GlcNAcylation by regulating the activity of OGT (O-GlcNAc transferase) and OGA (O-GlcNAcase) in H/R-treated H9c2 cells. Notably, molecular docking revealed the binding relationship between Kaempferol and OGT. Further, we proved that knockdown of OGT abrogated the function of Kaempferol in H/R-induced pyroptosis. In AMI mice, Kaempferol relieved the myocardial tissue injury and decreased the NLRP3 and GSDME-N protein levels. More importantly, our results illustrated that OGT was responsible for the O-GlcNAcylation of GSDME at T94 site and acted as an inducing factor for GSDME phosphorylation. Namely, this study validated that Kaempferol facilitated GSDME O-GlcNAcylation to inhibit H/R-induced pyroptosis in an OGT-dependent manner.

NLRP3 as a therapeutic target in cyclophosphamide-associated toxicities

Cyclophosphamide (CPM), a potent chemotherapeutic agent, while effective against various cancers, can cause significant organ damage. The NLRP3 inflammasome, a key player in the innate immune response, is implicated in this toxicity. This review delves into the intricate relationship between CPM and NLRP3 inflammasome activation, focusing on oxidative stress-mediated organ damage. We explore the mechanisms by which CPM induces NLRP3 activation in the kidneys, heart, liver, and gastrointestinal tract. Additionally, we examine the signaling pathways involved in this process. The review also discusses potential therapeutic interventions, including phytotherapeutic agents, that target NLRP3 inflammasome activation to mitigate CPM-induced organ injury. By highlighting the crucial role of NLRP3 in CPM-related toxicity, this review provides a foundation for future research aimed at developing novel therapeutic strategies to minimize adverse effects and improve patient outcomes.

Pyroptosis; igniting neuropsychiatric disorders from mild depression to aging-related neurodegeneration

Neuropsychiatric disorders significantly impact global health and socioeconomic well-being, highlighting the urgent need for effective treatments. Chronic inflammation, often driven by the innate immune system, is a key feature of many neuropsychiatric conditions. NOD-like receptors (NLRs), which are intracellular sensors, detect danger signals and trigger inflammation. Among these, NLR protein (NLRP) inflammasomes play a crucial role by releasing pro-inflammatory cytokines and inducing a particular cell death process known as pyroptosis. Pyroptosis is defined as a proinflammatory form of programmed cell death executed by cysteine-aspartic proteases, also known as caspases. Currently, the role of pyroptotic flux has emerged as a critical factor in innate immunity and the pathogenesis of multiple diseases. Emerging evidence suggests that the induction of pyroptosis, primarily due to NLRP inflammasome activation, is involved in the pathophysiology of various neuropsychiatric disorders, including depression, stress-related issues, schizophrenia, autism spectrum disorders, and neurodegenerative diseases. Within this framework, the current review explores the complex relationship between pyroptosis and neuropsychiatric diseases, aiming to identify potential therapeutic targets for these challenging conditions.

Unveiling the nexus: pyroptosis and its crucial implications in liver diseases

Pyroptosis, a distinctive form of programmed cell death orchestrated by gasdermin proteins, manifests as cellular rupture, accompanied by the release of inflammatory factors. While pyroptosis is integral to anti-infection immunity, its aberrant activation has been implicated in tumorigenesis. The liver, as the body's largest metabolic organ, is rich in various enzymes and governs metabolism. It is also the primary site for protein synthesis. Recent years have witnessed the emergence of pyroptosis as a significant player in the pathogenesis of specific liver diseases, exerting a pivotal role in both physiological and pathological processes. A comprehensive exploration of pyroptosis can unveil its contributions to the development and regression of conditions such as hepatitis, cirrhosis, and hepatocellular carcinoma, offering innovative perspectives for clinical prevention and treatment. This review consolidates current knowledge on key molecules involved in cellular pyroptosis and delineates their roles in liver diseases. Furthermore, we discuss the potential of leveraging pyroptosis as a novel or existing anti-cancer strategy.

Lactylation and regulated cell death

Lactylation, a newly identified post-translational modification, entails the attachment of lactate to lysine residues within proteins, profoundly modulating diverse cellular mechanisms underlying regulated cell death (RCD). This modification encompasses two primary categories: histone lactylation and non-histone lactylation. Histone lactylation assumes a pivotal regulatory function in the RCD process, primarily by modulating the transcriptional landscape of genes implicated in cell death. In contrast, non-histone lactylation exerts its influence by targeting transferases, transcription, cell cycle progression, death pathways, and metabolic processes that are intricately involved in RCD. This review provides a comprehensive overview of recent breakthroughs in understanding how lactylation regulates RCD, while also offering insights into potential avenues for future research, thereby deepening our comprehension of cellular fate determination.

Probenecid Inhibits NLRP3 Inflammasome Activity and Mitogen-Activated Protein Kinases (MAPKs)

Probenecid has long been a versatile drug in pharmacological therapies, primarily known for blocking active tubular secretion in the kidney, affecting both endogenous substances like uric acid and exogenous ones like penicillin. Beyond its renal applications, probenecid has shown capabilities in crossing the blood-brain barrier and modulating the activity of various membrane channels and transporters. This compound has emerged as a potent antiviral agent, demonstrating efficacy against multiple viruses, including influenza, COVID-19, and RSV. Clinical trials with COVID-19 patients have confirmed its antiviral potential, sparking further investigation into its mechanisms of action. This study explores probenecid's significant anti-inflammatory properties, focusing on its ability to inhibit inflammasome activation. Our study aims to unravel the anti-inflammatory effects of probenecid on the NLRP3 inflammasome and MAPK signaling pathways using murine macrophages as a relevant inflammation model. We reveal that probenecid treatment blocks JNK and ERK signaling without affecting p38 MAPK, suppressing NLRP3 inflammasome activation. Additionally, probenecid does not affect NFκB-directed protein expression, although it efficiently inhibits NLRP3 inflammasome outputs, e.g., IL-1β and pyroptosis. These results indicate probenecid's potential therapeutic applications.

Nicotinamide Riboside Mitigates Retinal Degeneration by Suppressing Damaged DNA-Stimulated Microglial Activation and STING-Mediated Pyroptosis

Purpose

Microglial activation plays a pivotal role in the pathogenesis of retinal degeneration, contributing to neuroinflammation within the retina. Previous studies identified that nicotinamide riboside (NR) mitigated light-induced retinal degeneration (LIRD) and inhibited microglial activation. The cGAS-STING signaling pathway has been recognized as a key mediator of inflammation in response to cellular stress and tissue damage. This study further explores the regulatory impact of NR on microglial activation and STING-mediated pyroptosis in retinal degeneration.

Methods

Balb/c mice were subjected to bright light exposure to induce retinal degeneration. Bioinformatics analysis was used to identify the upregulated key genes and signaling pathways involved in the progression of retinal degeneration, based on mouse transcriptomes from the LIRD model. Molecular biology techniques and immunofluorescence staining were used to assess cGAS-STING activation and expression of pyroptosis-associated molecules. Retinal function, photoreceptor apoptosis and inflammatory response were evaluated in the presence and absence of NR supplementation.

Results

Exposure to bright light resulted in mitochondrial dysfunction and the release of dsDNA, significantly triggering the activation of cGAS-STING pathway and microglial pyroptosis. In contrast, NR treatment preserved mitochondrial biosynthesis, inhibited STING expression in reactive microglia, and dampened the pro-inflammatory response. Additionally, intraperitoneal administration of the STING inhibitor H151 reduced light-induced microglial activation and pyroptosis, while improving retinal function and promoting photoreceptor survival.

Conclusions

These findings suggest that NR confers neuroprotection by attenuating damaged DNA-triggered STING-mediated microglial activation and pyroptosis. Targeting the cGAS-STING pathway presents a promising therapeutic avenue for retinal degeneration.

Ghrelin-LEAP2 interactions along the stomach-liver axis

Ghrelin produced in the stomach promotes food intake and GH secretion, and acts as an anabolic peptide during starvation. Ghrelin binds to the growth hormone secretagogue receptor, a G protein-coupled receptor (GPCR), whose high-resolution complex structures have been determined in the apo state and when bound to an antagonist. Anamorelin, a low-molecular-weight ghrelin agonist, has been launched in Japan for the treatment of cancer cachexia, and its therapeutic potential has attracted attention due to the various biological activities of ghrelin. In 2019, liver-expressed antimicrobial peptide (LEAP2), initially discovered as an antimicrobial peptide produced in the liver, was identified to be upregulated in the stomach of diet-induced obese mice after vertical sleeve gastrectomy. LEAP2 binds to the GHSR and antagonizes ghrelin's activities. The serum concentrations of human LEAP2 are positively correlated with body mass index, body fat accumulation, and fasting serum concentrations of glucose and triglyceride. Serum LEAP2 elevated and ghrelin reduced in obesity. Ghrelin and LEAP2 regulate body weight, food intake, and GH and blood glucose concentrations, and other physiological phenomena through their interactions with the same receptor, GHSR.

Necrosis-like cell death modes in heart failure: the influence of aetiology and the effects of RIP3 inhibition

Since cell dying in heart failure (HF) may vary based on the aetiology, we examined the main forms of regulated necrosis, such as necroptosis and pyroptosis, in the hearts damaged due to myocardial infarction (MI) or pressure overload. We also investigated the effects of a drug inhibiting RIP3, a proposed convergent point for both these necrosis-like cell death modes. In rat hearts, left ventricular function, remodelling, pro-cell death, and pro-inflammatory events were investigated, and the pharmacodynamic action of RIP3 inhibitor (GSK'872) was assessed. Regardless of the HF aetiology, the heart cells were dying due to necroptosis, albeit the upstream signals may be different. Pyroptosis was observed only in post-MI HF. The dysregulated miRNAs in post-MI hearts were accompanied by higher levels of a predicted target, HMGB1, its receptors (TLRs), as well as the exacerbation of inflammation likely originating from macrophages. The RIP3 inhibitor suppressed necroptosis, unlike pyroptosis, normalised the dysregulated miRNAs and tended to decrease collagen content and affect macrophage infiltration without affecting cardiac function or structure. The drug also mitigated the local heart inflammation and normalised the higher circulating HMGB1 in rats with post-MI HF. Elevated serum levels of HMGB1 were also detected in HF patients and positively correlated with C-reactive protein, highlighting pro-inflammatory axis. In conclusion, in MI-, but not pressure overload-induced HF, both necroptosis and pyroptosis operate and might underlie HF pathogenesis. The RIP3-targeting pharmacological intervention might protect the heart by preventing pro-death and pro-inflammatory mechanisms, however, additional strategies targeting multiple pro-death pathways may exhibit greater cardioprotection.

Emerging role of PANoptosis in kidney diseases: molecular mechanisms and therapeutic opportunities

Kidney diseases represent a significant global public health challenge, characterized by complex pathogenesis, high incidence, low awareness, insufficient early screening, and substantial treatment disparities. Effective therapeutic options remain lacking. Programmed cell death (PCD), including apoptosis, pyroptosis, and necroptosis, play pivotal roles in the pathogenesis of various kidney diseases. In 2019, PANoptosis, a novel form of inflammatory cell death, was introduced, providing new insights into innate immunity and PCD research. Although research on PANoptosis in kidney diseases is still limited, identifying key molecules within PANoptosomes and understanding their regulatory roles is critical for disease prevention and management. This review summarizes the various forms of PCD implicated in kidney diseases, along with PANoptosomes activated by Z-DNA binding protein 1 (ZBP1), absent in melanoma 2 (AIM2), receptor-interacting protein kinase 1 (RIPK1), NOD-like receptor family CARD domain containing 12 (NLRP12), and NOD-like receptor family member C5 (NLRC5). It also reviews the advancements in PANoptosis research in the field of kidney diseases, particularly in renal tumors and acute kidney injuries (AKI). The goal is to establish a foundation for future research into the role of PANoptosis in kidney diseases.

Synthetic RIG-I-Agonist RNA Induces Death of Hepatocellular Carcinoma Cells

Retinoic acid-inducible gene I (RIG-I) is a critical sensor of viral RNA and is activated in response to binding to RNA containing exposed 5'-triphosphate (5'ppp) and poly-uridine to trigger innate immune activation and response including induction of type I and III interferons (IFNs). RIG-I signaling plays a key role in not only restricting RNA virus infection but also suppressing tumor progression via oncolytic signaling. We evaluated the actions of a specific RIG-I agonist RNA (RAR) as a potential therapeutic against model tumor cell lines representing hepatocellular carcinoma (HCC). RAR constitutes a synthetic-modified RNA motif derived from the hepatitis C virus genome that is specifically recognized by RIG-I and induces innate immune activation when delivered to cells. We found that RAR directs RIG-I-dependent signaling to drive HCC cell death. Analysis of knockout cell lines lacking RIG-I, mitochondrial activator of virus signaling, or IRF3 confirmed that RAR-induced cell death signaling propagates through the RIG-I-like receptor (RLR) pathway to mediate caspase activation and HCC cell death. RAR-induced cell death is potentiated by type I IFN. Thus, RAR actions trigger HCC cell death through RIG-I linkage of RLR, caspase, and IFN signaling programs. RAR offers a potent application in antitumor therapeutic strategies leveraging innate immunity against liver cancer.

Pyroptosis for osteoarthritis treatment: insights into cellular and molecular interactions inflammatory

Osteoarthritis (OA) is a widely prevalent chronic degenerative disease often associated with significant pain and disability. It is characterized by the deterioration of cartilage and the extracellular matrix (ECM), synovial inflammation, and subchondral bone remodeling. Recent studies have highlighted pyroptosis-a form of programmed cell death triggered by the inflammasome-as a key factor in sustaining chronic inflammation. Central to this process are the inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18), which play crucial roles mediating intra-articular pyroptosis through the NOD-like receptor protein 3 (NLRP3) inflammasome. This paper investigates the role of the pyroptosis pathway in perpetuating chronic inflammatory diseases and its linkage with OA. Furthermore, it explores the mechanisms of pyroptosis, mediated by nuclear factor κB (NF-κB), the purinergic receptor P2X ligand-gated ion channel 7 (P2X7R), adenosine monophosphate (AMP)-activated protein kinase (AMPK), and hypoxia-inducible factor-1α (HIF-1α). Additionally, it examines the interactions among various cellular components in the context of OA. These insights indicate that targeting the regulation of pyroptosis presents a promising therapeutic approach for the prevention and treatment of OA, offering valuable theoretical perspectives for its effective management.

A Pyroptosis Radiosensitizer Facilitates Hypoxic Tumor Necrosis

Hypoxia-related tumor radioresistance markedly impairs the efficacy of radiotherapy. Herein, a targeted radiosensitization strategy is introduced, leveraging the upregulation of gasdermin C (GSDMC) in hypoxic tumor cells, aiming to induce pyroptosis through the application of a cobalt-containing polyoxometalate-based radiosensitizer. This novel radiosensitizer is designed for the precisely controlled release of cobalt ions upon X-ray irradiation, thereby activating caspase-8 and prompting the cleavage of GSDMC. This sequence of events selectively triggers pyroptosis in hypoxic tumor cells, directly addressing radioresistance. The ensuing results highlight the enhanced radiotherapy efficacy and tumor necrosis both in vitro and in vivo models. Overall, the findings confirm the effectiveness of this strategy targeting high GSDMC expression in hypoxic tumors to induce pyroptosis for precise radiotherapy. Such findings encourage further exploration of hypoxia-driven pyroptosis to improve cancer treatment outcomes.

Thymoquinone alleviates the accumulation of ROS and pyroptosis and promotes perforator skin flap survival through SIRT1/NF-κB pathway

Perforator flap transplantation is an important technique in flap reconstructive surgery, but flap necrosis limits its clinical effectiveness. Thymoquinone (TQ), a natural bioactive plant quinone found in black seed, exhibits anti-inflammatory, angiogenic, and antimicrobial properties. This study investigates the therapeutic effects of TQ in a perforator flap model through in vivo and in vitro experiments. Human umbilical vein endothelial cells (HUVECs) were treated with Tert-butyl Hydroperoxide (TBHP) to simulate an in vitro flap model and were then treated with TQ. In vivo experiments used a rat perforator flap model, and vascularization was assessed using Doppler ultrasound on days 3 and 7 after flap creation. On day 7 post-surgery, flap samples were collected to evaluate vascularity, reactive oxygen species, apoptosis and pyroptosis. Network pharmacology analysis was conducted to identify relevant signaling pathways, and molecular docking techniques were used to predict potential target binding sites. In vitro results showed that both TQ treatment and NLRP3 inhibitors reduced the expression of pyroptosis-related proteins. In vivo results indicated that the TQ-treated group had increased flap survival area, blood flow intensity, and microvascular density, while oxidative stress, apoptosis, and pyroptosis levels were reduced. Angiogenesis was enhanced, and expression of the SIRT1 protein was increased, while the p-P65/NF-κB/NLRP3 pathway was downregulated. After treatment with a SIRT1 inhibitor, flap survival rate and angiogenesis were reduced. These findings suggest that TQ improves perforator flap survival by inhibiting the NF-κB/NLRP3 pathway and promoting angiogenesis.

Chiral Nanofibers of Camptothecin Trigger Pyroptosis for Enhanced Immunotherapy

Camptothecin (CPT), a chemotherapeutic agent, demonstrates significant potential in cancer therapy. However, as a drug, CPT molecule suffers from poor water solubility, limited bioavailability, and insufficient immune response. Herein, we construct CPT nanofibers (CNF) with a right-handed chiral property via supramolecular self-assembly, which significantly overcomes the solubility barriers associated with bioavailability and improves tumor immune prognosis. The CNF exhibits high chiral asymmetry factor (gabs) (~0.11) and remarkable structure stability under pH 6.5 condition. By formulating chiral CNF with mitochondrial-targeted DSPE-PEG-TPP, CNF accumulates specifically in the mitochondria of cancer cells, leading to mitochondrial dysfunction and a 3.42-fold increase in reactive oxygen species (ROS) generation compared to the CPT molecule. This ROS amplification activates the caspase-1/gasdermin D (GSDMD) pathway, inducing pyroptosis that promotes M1 macrophage polarization and enhances CD8+ T-cell-dependent antitumor immunity. Consequently, CNF achieves 1.8-fold greater growth inhibition of distant tumor and reduces tumor metastasis compared to the CPT molecule. Our innovative platform, assembling CPT molecules into chiral CNF structure, is highly anticipated to overcome the current clinical limitations of CPT molecules and offer a new direction for the development of next-generation immunotherapy strategies.

Danshensu Attenuates Palmitic Acid-Induced Activation of Hepatic Stellate Cells by Regulating Pyroptosis

Introduction: We focused on examining the role of Danshensu in reducing reactive oxygen species (ROS) production and inhibiting NLRP3 inflammasome activation, which are key factors in liver fibrosis and inflammation. We sought to explore the potential of Danshensu as a therapeutic agent for liver fibrosis by targeting the pyroptosis-inflammasome signaling pathway, providing a basis for developing effective and safer NLRP3 inflammasome inhibitors. This study aimed to investigate whether Danshensu can mitigate palmitic acid (PA)-induced activation of hepatic stellate cells (HSCs) by regulating pyroptosis in HSC-T6 and LX-2 cells. Methods: HSC-T6 and LX-2 cell lines served as the cell models. A 2',7'-dichlorofluorescin diacetate reagent was used to measure ROS production within cells. Cell protein extraction was performed using radioimmunoprecipitation assay lysis buffer. The protein concentration in each sample was measured using a BCA assay kit. Western blot analysis was used with the SDS-polyacrylamide gel electrophoresis system. Results: PA-induced activation of HSC-T6 and LX-2 cells by upregulating alpha-smooth muscle actin, integrin-β1, and connective tissue growth factor. Danshensu mitigated PA-induced ROS accumulation in these cells. Moreover, Danshensu potentially reversed the upregulation of NLRP3, cleaved caspase 1, interleukin-1, GSDME, and ASC in PA-activated LX-2 cells via pyroptosis, suggesting its therapeutic potential. Pyroptosis inhibitor tetramethylthiuram disulfide reversed Danshensu attenuated PA activation of HSC-T6 and LX-2 cells, resulting in a 2-fold increase in alpha-smooth muscle actin, integrin-β1, and connective tissue growth factor. Conclusion: Danshensu effectively attenuates PA-induced HSC activation by reducing ROS production and inhibiting pyroptosis, offering a potential therapeutic strategy for liver fibrosis.

Ubiquitin Ligases in Control: Regulating NLRP3 Inflammasome Activation

Ubiquitin ligases play pivotal roles in the regulation of NLR family pyrin domain containing 3 (NLRP3) inflammasome activation, a critical process in innate immunity and inflammatory responses. This review explores the intricate mechanisms by which various E3 ubiquitin ligases exert both positive and negative influences on NLRP3 inflammasome activity through diverse post-translational modifications. Negative regulation of NLRP3 inflammasome assembly is mediated by several E3 ligases, including F-box and leucine-rich repeat protein 2 (FBXL2), tripartite motif-containing protein 31 (TRIM31), and Casitas B-lineage lymphoma b (Cbl-b), which induce K48-linked ubiquitination of NLRP3, targeting it for proteasomal degradation. Membrane-associated RING-CH 7 (MARCH7) similarly promotes K48-linked ubiquitination leading to autophagic degradation, while RING finger protein (RNF125) induces K63-linked ubiquitination to modulate NLRP3 function. Ariadne homolog 2 (ARIH2) targets the nucleotide-binding domain (NBD) domain of NLRP3, inhibiting its activation, and tripartite motif-containing protein (TRIM65) employs dual K48 and K63-linked ubiquitination to suppress inflammasome assembly. Conversely, Pellino2 exemplifies a positive regulator, promoting NLRP3 inflammasome activation through K63-linked ubiquitination. Additionally, ubiquitin ligases influence other components critical for inflammasome function. TNF receptor-associated factor 3 (TRAF3) mediates K63 polyubiquitination of apoptosis-associated speck-like protein containing a CARD (ASC), facilitating its degradation, while E3 ligases regulate caspase-1 activation and DEAH-box helicase 33 (DHX33)-NLRP3 complex formation through specific ubiquitination events. Beyond direct inflammasome regulation, ubiquitin ligases impact broader innate immune signaling pathways, modulating pattern-recognition receptor responses and dendritic cell maturation. Furthermore, they intricately control NOD1/NOD2 signaling through K63-linked polyubiquitination of receptor-interacting protein 2 (RIP2), crucial for nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) activation. Furthermore, we explore how various pathogens, including bacteria, viruses, and parasites, have evolved sophisticated strategies to hijack the host ubiquitination machinery, manipulating NLRP3 inflammasome activation to evade immune responses. This comprehensive analysis provides insights into the molecular mechanisms underlying inflammasome regulation and their implications for inflammatory diseases, offering potential avenues for therapeutic interventions targeting the NLRP3 inflammasome. In conclusion, ubiquitin ligases emerge as key regulators of NLRP3 inflammasome activation, exhibiting a complex array of functions that finely tune immune responses. Understanding these regulatory mechanisms not only sheds light on fundamental aspects of inflammation but also offers potential therapeutic avenues for inflammatory disorders and infectious diseases.