Igniting hope: Harnessing NLRP3 inflammasome-GSDMD-mediated pyroptosis for cancer immunotherapy.

In the contemporary landscape of oncology, immunotherapy, represented by immune checkpoint blockade (ICB) therapy, stands out as a beacon of innovation in cancer treatment. Despite its promise, the therapy's progression is hindered by suboptimal clinical response rates. Addressing this challenge, the modulation of the NLRP3 inflammasome-GSDMD-mediated pyroptosis pathway holds promise as a means to augment the efficacy of immunotherapy. In the pathway, the NLRP3 inflammasome serves as a pivotal molecular sensor that responds to inflammatory stimuli within the organism. Its activation leads to the release of cytokines interleukin 1ß and interleukin 18 through the cleavage of GSDMD, thereby forming membrane pores and potentially resulting in pyroptosis. This cascade of processes exerts a profound impact on tumor development and progression, with its function and expression exhibiting variability across different tumor types and developmental stages. Consequently, understanding the specific roles of the NLRP3 inflammasome and GSDMD-mediated pyroptosis in diverse tumors is imperative for comprehending tumorigenesis and crafting precise therapeutic strategies. This review aims to elucidate the structure and activation mechanisms of the NLRP3 inflammasome, as well as the induction mechanisms of GSDMD-mediated pyroptosis. Additionally, we provide a comprehensive overview of the involvement of this pathway in various cancer types and its applications in tumor immunotherapy, nanotherapy, and other fields. Emphasis is placed on the feasibility of leveraging this approach to enhance ICB therapy within the field of immunotherapy. Furthermore, we discuss the potential applications of this pathway in other immunotherapy methods, such as chimeric antigen receptor T-cell (CAR-T) therapy and tumor vaccines.

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-1ß, 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-1ß 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-1ß, 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-1ß, 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-1ß 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-1ß, 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.

Evaluation of immune and pyroptosis status in a model of sepsis-induced secondary pneumonia.

In recent years, researchers have focused on studying the mechanism of sepsis-induced immunosuppression, but there is still a lack of suitable animal models that accurately reflect the process of sepsis-induced immunosuppression. The aim of this study was to evaluate the immune status at various stages in a model of sepsis-induced secondary pneumonia and to demonstrate whether pyroptosis is one of the modes of immune cell death in sepsis. Firstly, we established a sepsis model in C57BL/6J mice using cecal ligation and puncture (CLP). The surviving mice were treated with a 40 µL suspension of P.aeruginosa (Pa) under anesthesia on day 4 post-CLP to establish a sepsis-induced secondary pneumonia model. Secondly, routine blood tests, serum ALT and PCT levels, gross lung specimens, and H&E staining of the lung and liver tissues were used to assess the successful establishment of this model. Serum levels of TNF-α and IL-6, the CD4+/CD8+ratio in blood, H&E staining of the spleen, and immunohistochemistry of CD4 and CD8 in the spleen were detected to evaluate the immune status of the model mice. Finally, the expression levels of pyroptosis-related proteins in the spleen were detected by Western blot. The expression of GSDMD was assessed using immunohistochemistry, and pyroptosis was directly observed through transmission electron microscopy. The experimental results above confirmed the successful construction of the model for sepsis-induced secondary pneumonia, demonstrating its ability to reflect sepsis-induced immunosuppression. Moreover, the expression of pyroptosis-related proteins, immunohistochemical GSDMD, and transmission electron microscopy of the spleen showed that pyroptosis was one of the modes of immune cell death in sepsis.

Bile acids attenuate hepatic inflammation during ischemia/reperfusion injury.

Background & Aims: Persistent cholestasis has been associated with poor prognosis after orthotopic liver transplantation. In this study, we aimed to investigate how the accumulation of tauro-beta-muricholic acid (TßMCA), resulting from the reprogramming of bile acid (BA) metabolism during liver ischemia/reperfusion (IR) stress, attenuates liver inflammation. Methods: Ingenuity Pathway Analysis was performed using transcriptome data from a murine hepatic IR model. Three different models of hepatic IR (liver warm IR, bile duct separation-IR, common bile duct ligation-IR) were employed. We generated adeno-associated virus-transfected mice and CD11b-DTR mice to assess the role of BAs in regulating the myeloid S1PR2-GSDMD axis. Hepatic BA levels were analyzed using targeted metabolomics. Finally, the correlation between the reprogramming of BA metabolism and hepatic S1PR2 levels was validated through RNA-seq of human liver transplant biopsies. Results: We found that BA metabolism underwent reprogramming in murine hepatocytes under IR stress, leading to increased synthesis of TßMCA, catalyzed by the enzyme CYP2C70. The levels of hepatic TßMCA were negatively correlated with the severity of hepatic inflammation, as indicated by the serum IL-1ß levels. Inhibition of hepatic CYP2C70 resulted in reduced TßMCA production, which subsequently increased serum IL-1ß levels and exacerbated IR injury. Moreover, our findings suggested that TßMCA could inhibit canonical inflammasome activation in macrophages and attenuate inflammatory responses in a myeloid-specific S1PR2-GSDMD-dependent manner. Additionally, Gly-ßMCA, a derivative of TßMCA, could effectively attenuate inflammatory injury in vivo and inhibit human macrophage pyroptosis in vitro. Conclusions: IR stress orchestrates hepatic BA metabolism to generate TßMCA, which attenuates hepatic inflammatory injury by inhibiting the myeloid S1PR2-GSDMD axis. Bile acids have immunomodulatory functions in liver reperfusion injury that may guide therapeutic strategies. Impact and implications: Our research reveals that liver ischemia-reperfusion stress triggers reprogramming of bile acid metabolism. This functions as an adaptive mechanism to mitigate inflammatory injury by regulating the S1PR2-GSDMD axis, thereby controlling the release of IL-1ß from macrophages. Our results highlight the crucial role of bile acids in regulating hepatocyte-immune cell crosstalk, which demonstrates an immunomodulatory function in liver reperfusion injury that may guide therapeutic strategies targeting bile acids and their receptors.

Multiple sclerosis: the NLRP3 inflammasome, gasdermin D, and therapeutics.

Multiple sclerosis (MS) stands as a chronic inflammatory disease characterized by its neurodegenerative impacts on the central nervous system. The complexity of MS and the significant challenges it poses to patients have made the exploration of effective treatments a crucial area of research. Among the various mechanisms under investigation, the role of inflammation in MS progression is of particular interest. Inflammatory responses within the body are regulated by various cellular mechanisms, one of which involves the nucleotide-binding oligomerization domain (NOD)-, leucine-rich repeat (LRR)-, and pyrin domains (PYD)-containing protein 3 (NLRP3). NLRP3 acts as a sensor within cells, playing a pivotal role in controlling the inflammatory response. Its activation is a critical step leading to the assembly of the NLRP3 inflammasome complex, a process that has profound implications for inflammatory diseases like MS. The NLRP3 inflammasome's activation is intricately linked to the subsequent activation of caspase 1 and gasdermin D (GsdmD), signaling pathways that are central to the inflammatory process. GsdmD, a prominent member of the Gasdermin protein family, is particularly noteworthy for its role in pyroptotic cell death, a form of programmed cell death that is distinct from apoptosis and is characterized by its inflammatory nature. This pathway's activation contributes significantly to the pathology of MS by exacerbating inflammatory responses within the nervous system. Given the detrimental effects of unregulated inflammation in MS, therapeutics targeting these inflammatory processes offer a promising avenue for alleviating the symptoms experienced by patients. This review delves into the intricacies of the pyroptotic pathways, highlighting how the formation of the NLRP3 inflammasome induces such pathways and the potential intervention points for therapeutic agents. By inhibiting key steps within these pathways, it is possible to mitigate the inflammatory response, thereby offering relief to those suffering from MS. Understanding these mechanisms not only sheds light on the pathophysiology of MS but also paves the way for the development of novel therapeutic strategies aimed at controlling the disease's progression through the modulation of the body's inflammatory response.

Atramacronoid A induces the PANoptosis-like cell death of human breast cancer cells through the CASP-3/PARP-GSDMD-MLKL pathways.

Breast cancer is the most common malignant tumor and a major cause of mortality among women worldwide. Atramacronoid A (AM-A) is a unique natural sesquiterpene lactone isolated from the rhizome of Atractylodes macrocephala Koidz (known as Baizhu in Chinese). Our study demonstrated that AM-A triggers a specific form of cell death resembling PANoptosis-like cell death. Further analysis indicated that AM-A-induced PANoptosis-like cell death is associated with the CASP-3/PARP-GSDMD-MLKL pathways, which are mediated by mitochondrial dysfunction. These results suggest the potential of AM-A as a lead compound and offer insights for the development of therapeutic agents for breast cancer from natural products.

The Protective Effect of Melatonin on LPS-Induced Myocardial Injury via the Caspase-11/GSDMD Pathway.

BACKGROUND: Melatonin (MT) has been demonstrated to have cardioprotective effects. Nevertheless, the precise mechanism through which MT provides protection against the etiology of LPS-induced myocardial injury remains uncertain. In this investigation, our objective was to explore the impact of MT on LPS-induced myocardial injury in an in vitro setting. METHODS: H9C2 cells were categorized into four groups: a control group (H9C2 group), an MT group, an LPS group, and an MT + LPS group. The H9C2 group received treatment with sterile saline solution, the LPS group was exposed to 5 µg/mL LPS for 24 hours, the MT + LPS group underwent pretreatment with 150 µmol/L MT for 2 hours, followed by exposure to 5 µg/mL LPS for 24 hours, and the MT group received only 150 µmol/L MT for 2 hours. Cell viability and lactate dehydrogenase (LDH) release were assessed using the CCK-8 assay and LDH activity assay, respectively. The levels of reactive oxygen species (ROS) were quantified in each group of cells, and the percentage of propidium iodide (PI)-stained apoptotic cells was determined by flow cytometry. The mRNA levels of caspase11, GSDMD, and IL-18 in each group of cells were quantified. RESULTS: MT treatment significantly protected H9C2 cells from LPS-induced damage, as evidenced by decreased LDH release. LPS treatment markedly increased ROS levels in H9C2 cells, which were subsequently reduced by MT. LPS caused a substantial decrease in superoxide dismutase (SOD) activity and a significant increase in malondialdehyde (MDA) levels, while MT treatment significantly reversed these effects. Additionally, MT markedly enhanced the proportion of viable H9C2 cells compared to LPS-treated controls, as evidenced by the PI staining assay. LPS upregulated both mRNA levels and protein levels of IL-18 in H9C2 cells. However, MT treatment effectively mitigated this LPS-induced increase. Furthermore, MT significantly decreased LPS-induced protein levels of cleaved-caspase 11 and GSDMD-N in H9C2 cells. CONCLUSION: Overall, our findings suggest that MT inhibits the Caspase11-GSDMD signaling pathway via pyroptosis-related proteins (caspase-11 and GSDMD-N) and reduces the expression of inflammation-related cytokines (IL-18), thereby exerting a protective effect on H9C2 cells after LPS injury.

Gasdermin D Mediated Mitochondrial Metabolism Orchestrate Neurogenesis Through LDHA During Embryonic Development.

Regulatory cell death is an important way to eliminate the DNA damage that accompanies the rapid proliferation of neural stem cells during cortical development, including pyroptosis, apoptosis, and so on. Here, the study reports that the absence of GSDMD-mediated pyroptosis results in defective DNA damage sensor pathways accompanied by aberrant neurogenesis and autism-like behaviors in adult mice. Furthermore, GSDMD is involved in organizing the mitochondrial electron transport chain by regulating the AMPK/PGC-1α pathway to target Aifm3. This process promotes a switch from oxidative phosphorylation to glycolysis. The perturbation of metabolic homeostasis in neural progenitor cells increases lactate production which acts as a signaling molecule to regulate the p38MAPK pathway. And activates NF-𝜿B transcription to disrupt cortex development. This abnormal proliferation of neural progenitor cells can be rescued by inhibiting glycolysis and lactate production. Taken together, the study proposes a metabolic axis regulated by GSDMD that links pyroptosis with metabolic reprogramming. It provides a flexible perspective for the treatment of neurological disorders caused by genotoxic stress and neurodevelopmental disorders such as autism.

Inducers and Inhibitors of Pyroptotic Death of Granulosa Cells in Models of Premature Ovarian Insufficiency and Polycystic Ovary Syndrome.

Granulosa cells (GCs), the largest cell population and primary source of steroid hormones in the ovary, are the important somatic ovarian components. They have critical roles in folliculogenesis by supporting oocyte, facilitating its growth, and providing a microenvironment suitable for follicular development and oocyte maturation, thus having essential functions in maintaining female fertility and in reproductive health in general. Pyroptotic death of GCs and associated inflammation have been implicated in the pathogenesis of several reproductive disorders in females including Premature Ovarian Insufficiency (POI) and Polycystic Ovary Syndrome (PCOS). Here, I reviewed factors, either intrinsic or extrinsic, that induce or inhibit pyroptosis in GCs in various models of these disorders, both in vitro and in vivo, and also covered associated molecular mechanisms. Most of these studied factors influence NLRP3 inflammasome- and GSDMD (Gasdermin D)-mediated pyroptosis in GCs, compared to other inflammasomes and gasdermins (GSDMs). I conclude that a more complete mechanistic understanding of these factors in terms of GC pyroptosis is required to be able to develop novel strategies targeting inflammatory cell death in the ovary.

The role and mechanism of pyroptosis and potential therapeutic targets in non-alcoholic fatty liver disease (NAFLD).

Non-alcoholic fatty liver disease (NAFLD) is a clinical pathological syndrome characterized by the excessive accumulation of fat within liver cells, which can progress to end-stage liver disease in severe cases, posing a threat to life. Pyroptosis is a distinct, pro-inflammatory form of cell death, differing from traditional apoptosis. In recent years, there has been growing research interest in the association between pyroptosis and NAFLD, encompassing the mechanisms and functions of pyroptosis in the progression of NAFLD, as well as potential therapeutic targets. Controlled pyroptosis can activate immune cells, eliciting host immune responses to shield the body from harm. However, undue activation of pyroptosis may worsen inflammatory responses, induce cellular or tissue damage, disrupt immune responses, and potentially impact liver function. This review elucidates the involvement of pyroptosis and key molecular players, including NOD-like receptor thermal protein domain associated protein 3(NLRP3) inflammasome, gasdermin D (GSDMD), and the caspase family, in the pathogenesis and progression of NAFLD. It emphasizes the promising prospects of targeting pyroptosis as a therapeutic approach for NAFLD and offers valuable insights into future directions in the field of NAFLD treatment.

Rabies Virus Infection Causes Pyroptosis of Neuronal Cells.

Rabies virus (RABV) is a neurotropic virus that causes fatal neurological disease, raising serious public health issues and attracting extensive attention in society. To elucidate the molecular mechanism of RABV-induced neuronal damage, we used hematoxylin-eosin staining, transmission electron microscopy, transcriptomics analysis, and immune response factor testing to investigate RABV-infected neurons. We successfully isolated the neurons from murine brains. The specificity of the isolated neurons was identified by a monoclonal antibody, and the viability of the neurons was 83.53-95.0%. We confirmed that RABV infection induced serious damage to the neurons according to histochemistry and transmission electron microscope (TEM) scanning. In addition, the transcriptomics analysis suggested that multiple genes related to the pyroptosis pathway were significantly upregulated, including gasdermin D (Gsdmd), Nlrp3, caspase-1, and IL-1ß, as well as the chemokine genes Ccl2, Ccl3, Ccl4, Ccl5, Ccl7, Ccl12, and Cxcl10. We next verified this finding in the brains of mice infected with the rRC-HL, GX074, and challenge virus standard strain-24 (CVS-24) strains of RABV. Importantly, we found that the expression level of the Gsdmd protein was significantly upregulated in the neurons infected with different RABV strains and ranged from 691.1 to 5764.96 pg/mL, while the basal level of mock-infected neurons was less than 100 pg/mL. Taken together, our findings suggest that Gsdmd-induced pyroptosis is involved in the neuron damage caused by RABV infection.

Pyroptosis in Diabetic Peripheral Neuropathy and its Therapeutic Regulation.

Pyroptosis is a pro-inflammatory form of cell death resulting from the activation of gasdermins (GSDMs) pore-forming proteins and the release of several pro-inflammatory factors. However, inflammasomes are the intracellular protein complexes that cleave gasdermin D (GSDMD), leading to the formation of robust cell membrane pores and the initiation of pyroptosis. Inflammasome activation and gasdermin-mediated membrane pore formation are the important intrinsic processes in the classical pyroptotic signaling pathway. Overactivation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome triggers pyroptosis and amplifies inflammation. Current evidence suggests that the overactivation of inflammasomes and pyroptosis may further induce the progression of cancers, nerve injury, inflammatory disorders and metabolic dysfunctions. Current evidence also indicates that pyroptosis-dependent cell death accelerates the progression of diabetes and its frequent consequences including diabetic peripheral neuropathy (DPN). Pyroptosis-mediated inflammatory reaction further exacerbates DPN-mediated CNS injury. Accumulating evidence shows that several molecular signaling mechanisms trigger pyroptosis in insulin-producing cells, further leading to the development of DPN. Numerous studies have suggested that certain natural compounds or drugs may possess promising pharmacological properties by modulating inflammasomes and pyroptosis, thereby offering potential preventive and practical therapeutic approaches for the treatment and management of DPN. This review elaborates on the underlying molecular mechanisms of pyroptosis and explores possible therapeutic strategies for regulating pyroptosis-regulated cell death in the pharmacological treatment of DPN.

Ginsenoside Rg1 Suppresses Pyroptosis via the NF-κB/NLRP3/GSDMD Pathway to Alleviate Chronic Atrophic Gastritis In Vitro and In Vivo.

Chronic atrophic gastritis (CAG) is characterized by the loss of gastric glandular cells, which are replaced by the intestinal-type epithelium and fibrous tissue. Ginsenoside Rg1 (Rg1) is the prevalent ginsenoside in ginseng, with a variety of biological activities, and is usually added to functional foods. As a novel form of programmed cell death (PCD), pyroptosis has received substantial attention in recent years. Despite the numerous beneficial effects, the curative impact of Rg1 on CAG and whether its putative mechanism is partially via inhibiting pyroptosis still remain unknown. To address this gap, we conducted a study to explore the mechanisms underlying the potential anti-CAG effect of Rg1. We constructed a CAG rat model using a multifactor comprehensive method. A cellular model was developed by using 1-methyl-3-nitro-1-nitrosoguanidine (MNNG) combined with Nigericin as a stimulus applied to GES-1 cells. After Rg1 intervention, the levels of inflammatory indicators in the gastric tissue/cell supernatant were reduced. Rg1 relieved oxidative stress via reducing the myeloperoxidase (MPO) and malonaldehyde (MDA) levels in the gastric tissue and increasing the level of superoxide dismutase (SOD). Additionally, Rg1 improved MNNG+Nigericin-induced pyroptosis in the morphology and plasma membrane of the cells. Further research supported novel evidence for Rg1 in the regulation of the NF-κB/NLRP3/GSDMD pathway and the resulting pyroptosis underlying its therapeutic effect. Moreover, by overexpression and knockout of GSDMD in GES-1 cells, our findings suggested that GSDMD might serve as the key target in the effect of Rg1 on suppressing pyroptosis. All of these offer a potential theoretical foundation for applying Rg1 in ameliorating CAG.

Oxymatrine Attenuates Ulcerative Colitis through Inhibiting Pyroptosis Mediated by the NLRP3 Inflammasome.

Ulcerative colitis (UC) is difficult to cure and easy to relapse, leading to poor quality of life for patients. Oxymatrine (OMT) is one of the main alkaloids of Sophora flavescens Aiton, which has many effects, such as anti-inflammation, anti-oxidative stress, and immunosuppression. This study aimed to investigate whether OMT could attenuate ulcerative colitis by inhibiting the NOD-like receptor family pyrin domain containing three (NLRP3) inflammasome-mediated pyroptosis. In this study, the UC rat models were established by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) in vivo, while RAW264.7 cells and peritoneal macrophages were stimulated with Lipopolysaccharides/Adenosine Triphosphate (LPS/ATP) in vitro to simulate pyroptosis models, and Western blotting (WB) and other detection techniques were applied to analyze proteins involved in the NLRP3 inflammasome pathway. Our results showed that OMT alleviated colitis ulcers and pathological damage in the TNBS-induced UC rats and exhibited an inhibitory effect on pyroptosis at the early stage of UC. In the model group, the pyroptosis reached the peak at 24 h after modeling with the contents of active-cysteine-aspartic proteases-1 (caspase-1), Gasdermin D (GSDMD)-N, and cleaved-interleukin-1 beta (IL-1ß) to the highest expression level. Meanwhile, we found that OMT (80 mg kg-1) remarkably decreased the expression levels of NLRP3, active-caspase-1, and cleaved-IL-1ß at 24 h in the lesion tissue from UC rats. Further experiments on cells demonstrated that OMT at concentrations of 100 and 250 µM significantly inhibited cell death caused by NLRP3 inflammasome activation (p < 0.05), downregulated caspase-1, GSDMD, and decreased the levels of active-caspase-1, GSDMD-N, cleaved-IL-1ß in RAW326.7 cells, and peritoneal macrophages. In summary, these results indicated that OMT could attenuate ulcerative colitis through inhibiting pyroptosis mediated by the NLRP3 inflammasome. The inhibition of the NLRP3 inflammasome may be a potential strategy for UC.

Human Coronavirus 229E Infection Inactivates Pyroptosis Executioner Gasdermin D but Ultimately Leads to Lytic Cell Death Partly Mediated by Gasdermin E.

Human coronavirus 229E (HCoV-229E) is associated with upper respiratory tract infections and generally causes mild respiratory symptoms. HCoV-229E infection can cause cell death, but the molecular pathways that lead to virus-induced cell death as well as the interplay between viral proteins and cellular cell death effectors remain poorly characterized for HCoV-229E. Studying how HCoV-229E and other common cold coronaviruses interact with and affect cell death pathways may help to understand its pathogenesis and compare it to that of highly pathogenic coronaviruses. Here, we report that the main protease (Mpro) of HCoV-229E can cleave gasdermin D (GSDMD) at two different sites (Q29 and Q193) within its active N-terminal domain to generate fragments that are now unable to cause pyroptosis, a form of lytic cell death normally executed by this protein. Despite GSDMD cleavage by HCoV-229E Mpro, we show that HCoV-229E infection still leads to lytic cell death. We demonstrate that during virus infection caspase-3 cleaves and activates gasdermin E (GSDME), another key executioner of pyroptosis. Accordingly, GSDME knockout cells show a significant decrease in lytic cell death upon virus infection. Finally, we show that HCoV-229E infection leads to increased lytic cell death levels in cells expressing a GSDMD mutant uncleavable by Mpro (GSDMD Q29A+Q193A). We conclude that GSDMD is inactivated by Mpro during HCoV-229E infection, preventing GSDMD-mediated cell death, and point to the caspase-3/GSDME axis as an important player in the execution of virus-induced cell death. In the context of similar reported findings for highly pathogenic coronaviruses, our results suggest that these mechanisms do not contribute to differences in pathogenicity among coronaviruses. Nonetheless, understanding the interactions of common cold-associated coronaviruses and their proteins with the programmed cell death machineries may lead to new clues for coronavirus control strategies.

Inhibition of GSDMD-dependent pyroptosis decreased methamphetamine self-administration in rats.

It is widely believed that the activation of the central dopamine (DA) system is crucial to the rewarding effects of methamphetamine (METH) and to the behavioral outcomes of METH use disorder. It was reported that METH exposure induced gasdermin D (GSDMD)-dependent pyroptosis in rats. The membrane pore formation caused by METH-induced pyroptosis may also contribute to the overflow of DA into the extracellular space and subsequently increase the DA levels in the brain. The present study firstly investigated whether the membrane pore information induced by GSDMD-dependent pyroptosis was associated with the increased DA levels in the ventral tegmental area (VAT) and nucleus accumbens (NAc) of rats self-administering METH and SY-SH5Y cells treated by METH. Subsequently, the effect of pore formation blockade or genetic inhibition of GSDMD on the reinforcing and motivational effect of METH was determined in rats, using the animal model of METH self-administration (SA). METH exposure significantly increased the activity of NLRP1/Cas-1/GSDMD pathway and the presence of pyroptosis, accompanied by the significantly increased DA levels in VTA and NAc. Moreover, intraperitoneal injections of disulfiram (DSF) or microinjection of rAAV-shGSDMD into VTA/NAc significantly reduced the reinforcing and motivational effect of METH, accompanied by the decreased level of DA in VTA and NAc. The results provided novel evidence that METH-induced pyroptosis could increase DA release in VTA and NAc via the NLRP1/Cas-1/GSDMD pathway. Additionally, membrane pores or GSDMD blockade could significantly reduce the reinforcing and motivational effect of METH. In conclusion, blocking GSDMD and membrane pore formation could be a promising potential target for the development of agents to treat METH use disorder.

Dexmedetomidine enhances Mitophagy via PINK1 to alleviate hippocampal neuronal Pyroptosis and improve postoperative cognitive dysfunction in elderly rat.

Postoperative cognitive dysfunction (POCD) is a common complication in elderly surgical patients, significantly affecting their quality of life. Dexmedetomidine (Dex), an anesthetic, has shown promise in alleviating POCD, but its underlying mechanism remains unclear. This study aims to explore how Dex improves POCD in aged rats by targeting the PINK1-mediated mitochondrial autophagy pathway, reducing caspase-1/11-GSDMD-induced hippocampal neuronal pyroptosis. Transcriptome sequencing identified 300 differentially expressed genes enriched in the mitochondrial autophagy pathway in Dex-treated POCD rat hippocampal tissue, with Pink1 as a key candidate. In a POCD rat model, Dex treatment upregulated hippocampal PINK1 expression. In vitro experiments using H19-7 rat hippocampal neurons revealed that Dex enhanced mitochondrial autophagy and suppressed neuronal pyroptosis by upregulating PINK1. Further mechanistic validation demonstrated that Dex activated PINK1-mediated mitochondrial autophagy, inhibiting caspase-1/11-GSDMD-induced neuronal pyroptosis. In vivo experiments confirmed Dex's ability to reduce caspase-1/11-GSDMD-dependent hippocampal neuronal pyroptosis and improve postoperative cognitive function in aged rats. Dexmedetomidine improves postoperative cognitive dysfunction in elderly rats by enhancing mitochondrial autophagy via PINK1 upregulation, mitigating caspase-1/11-GSDMD-induced neuronal pyroptosis.

Effect of IL-9 neutralising antibody on pyroptosis via SGK1/NF-κB/NLRP3/GSDMD in allergic rhinitis mice.

Allergic rhinitis is a common non-infectious inflammatory disease that affects approximately 15 % of people worldwide and has a complex and unclear aetiology. In recent years, pyroptosis has been found to play a role in the development of allergic rhinitis. IL-9, pyroptosis, serum and glucocorticoid-induced protein kinase 1 (SGK1), NOD-like receptor 3 (NLRP3), and nuclear factor kappa B (NF-κB) have been shown to influence each other. Herein, we aimed to explore the role of IL-9 neutralising antibody in pyroptosis involving IL-9, SGK1, NF-κB, and NLRP3 in allergic rhinitis. We observed a decrease in cytokines involved in pyroptosis and gasdermin D (GSDMD) compared with those in mice with allergic rhinitis. Further, phosphorylation of NF-κB/p65 decreased compared with that in mice with allergic rhinitis; NLRP3 and ASC also decreased, although the levels were higher than those in controls. SGK1 levels decreased compared with that in mice with allergic rhinitis and increased after using IL-9 neutralising antibodies, thus demonstrating its negative regulatory effects. The IL-9 neutralising antibody reduced the inflammatory and pyroptosis responses via SGK1 and NF-κB/NLRP3/GSDMD pathway. Our research results indicate that IL-9 regulates allergic rhinitis via the influence of SGK1 and NF-κB/NLRP3/GSDMD signalling pathway, providing new insights for developing novel drugs to treat allergic rhinitis.

Cadmium activates the innate immune system through the AIM2 inflammasome.

Cadmium (Cd) is a widely used heavy metal and has recently been recognized as a possible source of human toxicity due to its ability to accumulate in organs. Accumulation of heavy metals has several adverse effects, including inducing inflammation, in multiple organs, such as the testis. However, how Cd ions are sensed by host cells and how tissue inflammation eventually occurs remains unclear. Here, we show that Cd activates the AIM2 inflammasome by mediating genomic DNA release into the cytoplasm after DNA damage via oxidative stress, to trigger IL-1ß secretion and pyroptosis. Specifically, the toxicity effects induced by Cd in cells were prevented by melatonin, which served as an antagonist of oxidative stress. Accordingly, in a mouse model, Cd-induced inflammation in the testis and consequential male reproductive dysfunction were effectively reversed by melatonin. Thus, our results suggest a function of AIM2 in Cd-mediated testis inflammation and identify AIM2 as a major pattern recognition receptor in response to heavy metal Cd ions.