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Atherosclerosis and abdominal aortic aneurysm (AAA) are multifactorial diseases characterized by inflammatory cell infiltration, matrix degradation, and thrombosis in the arterial wall. Although there are some differences between atherosclerosis and AAA, inflammation is a prominent common feature of these disorders. The nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a cytosolic multiprotein complex that activates caspase-1 and regulates the release of proinflammatory cytokines interleukin (IL)-1β and IL-18, as well as the induction of lytic cell death, termed pyroptosis, thereby leading to inflammation. Previous experimental and clinical studies have demonstrated that inflammation in atherosclerosis and AAA is mediated primarily through the NLRP3 inflammasome. Furthermore, recent results of the Canakinumab Anti-inflammatory Thrombosis and Outcome Study (CANTOS) showed that IL-1β inhibition reduces systemic inflammation and prevents atherothrombotic events; this supports the concept that the NLRP3 inflammasome is a promising therapeutic target for cardiovascular diseases, including atherosclerosis and AAA. This review summarizes current knowledge with a focus on the role of the NLRP3 inflammasome in atherosclerosis and AAA, and discusses the prospects of NLRP3 inflammasome-targeted therapy.

Background/purpose: Pyroptosis is a form of programmed cell death dependent on the activation of caspase-1. Porphyromonas gingivalis (P. gingivalis) is a major pathogenic bacterium in periodontitis and its lipopolysaccharide (LPS) can trigger inflammation. However, whether P. gingivalis-LPS affects epithelial connections or triggers pyroptosis in the gingival epithelium is unknown. Materials and methods: Gingival samples from human donors were collected and the expression levels of E-cadherin, nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), caspase-1/4/5, interleukin (IL)-18, and IL-1β were examined. P. gingivalis-LPS was injected into rat gingival sulcus to establish gingivitis models, and the expression levels of E-cadherin, NLRP3, caspase-1/11, IL-18, and IL-1β were compared via immunohistochemistry. The mRNA levels of E-cadherin, caspase-1, IL-18, and IL-1β were evaluated in oral mucosa epithelial cells (OMECs) and rat gingival tissues. Results: In the present study, NLRP3 (p

Myocardial injury is a severe complication of sepsis and contributes substantially to the death of critically ill patients. Long non-coding RNAs (lncRNAs) participate in the pathogenesis of sepsis-induced myocardial injury. In this study, we investigated the role of lncRNA X-inactive specific transcript (XIST) in septic myocardial injury and explored its mechanism. Lipopolysaccharide (LPS)-stimulated H9C2 cells and rats subjected to cecal ligation and puncture (CLP) were used as the in vitro and in vivo models. After exposure to LPS, XIST and c-Fos levels were upregulated, but miR-150-5p was downregulated in H9C2 cardiomyocytes and myocardial tissues. XIST affected viability, apoptosis, and pyroptosis in LPS-challenged H9C2 cells. Moreover, XIST knockdown attenuated LPS-induced injury in H9C2 cells by targeting the miR-150-5p/c-Fos axis. c-Fos could bound to the promoter of the TXNIP/XIST gene and enhanced TXNIP/XIST expression. Silencing of XIST improved cardiac function and survival rate and reduced apoptosis and pyroptosis by regulating the miR-150-5p/c-Fos axis in septic rats in vivo. Taken together, our data show that XIST/miR-150-5p/c-Fos axis affected septic myocardial injury, which may indicate a novel therapeutic strategy for sepsis-induced myocardial injury.

Dexmedetomidine (Dex) has been suggested to exert a protective function in ischemic brain injury. In this study, we aimed to elucidate the intrinsic mechanisms of Dex in regulating microglia pyroptosis in ischemic brain injury via the purinergic 2X7 receptor (P2X7R)/NLRP3/Caspase-1 signaling pathway. First, permanent middle cerebral artery occlusion (p-MCAO) rat model was established, followed by the measurement of behavioral deficit, neuronal injury, the volume of brain edema and the infarct size. Dex treatment was suggested to alleviate the neurological deficits in p-MCAO rats and reduce the brain water content and infarct size. Additionally, rat microglia were cultured in vitro and a model of oxygen and glucose (OGD) was established. Microglia cell activity and ultrastructure were detected. Dex could increase cell activity and reduce LDH activity, partially reversing the changes in cell morphology. Furthermore, the activation of P2X7R/NLRP3/Caspase-1 pathway was tested. The obtained findings indicated Dex suppressed microglial pyroptosis by inhibiting the P2X7R/NLRP3/Caspase-1 pathway. Inhibition of P2X7R or NLRP3 could inhibit Caspase-1 p10 expression, improve cell activity, and reduce LDH activity. The same result was verified in vivo experiments. This study indicated that Dex inhibited microglia pyroptosis by blocking the P2X7R/NLRP3/Caspase-1 pathway, thus playing a protective role against ischemic brain injury.

Myocardial infarction (MI)-induced the activation of NLRP3 inflammasome has been well known to aggravate myocardial injury and cardiac dysfunction by causing inflammation and pyroptosis in the heart. Circular RNAs (circRNAs) have been demonstrated to play critical roles in cardiovascular diseases. However, the functions and mechanisms of circRNAs in modulating cardiac inflammatory response and cardiomyocyte pyroptosis remain largely unknown. We revealed that circHelz, a novel circRNA transcribed from the helicase with zinc finger (Helz) gene, was significantly upregulated in both the ischemic myocardium of MI mouse and neonatal mouse ventricular cardiomyocytes (NMVCs) exposed to hypoxia. Overexpression of circHelz caused cardiomyocyte injury in NMVCs by activating the NLRP3 inflammasome and inducing pyroptosis, while circHelz silencing reduced these effects induced by hypoxia. Furthermore, knockdown of circHelz remarkably attenuated NLRP3 expression, decreased myocardial infarct size, pyroptosis, inflammation, and increased cardiac function in vivo after MI. Overexpression of miR-133a-3p in cardiomyocytes greatly prevented pyroptosis in the presence of hypoxia or circHelz by targeting NLRP3 in NMVCs. Mechanistically, circHelz functioned as an endogenous sponge for miR-133a-3p via suppressing its activity. Overall, our results demonstrate that circHelz causes myocardial injury by triggering the NLRP3 inflammasome-mediated pro-inflammatory response and subsequent pyroptosis in cardiomyocytes by inhibiting miR-133a-3p function. Therefore, interfering with circHelz/miR-133a-3p/NLRP3 axis might be a promising therapeutic approach for ischemic cardiac diseases.

Congenital clubfoot (CCF) is a common birth defect. Maternal smoking during pregnancy increases the risk of CCF. In previous research, we found muscle phenotypes similar to CCF in four and a half LIM domain protein 1 (FHLI) offspring mice (FHL1-/y). However, the role of P2RX7-mediated pyroptosis in the effect of cigarette smoke (CS) on the skeletal muscle of FHL1-/y mice during pregnancy is unclear. In the present study, pregnant mice at 11 days of gestation were exposed to CS and male offspring of wild-type (WT) and FHL1-/y mice were divided into four groups (Control-WT, Control-KO, CS-WT, CS-KO). The histomorphology of lower limb muscles was examined using hematoxylin and eosin (HE these two factors had an additive effect. The results showed maternal smoking during pregnancy aggravated muscle phenotype similar to CCF in FHL1-/y offspring mice through P2RX7-mediated pyroptosis.

Epilepsy is one of the most prevalent serious brain disorders worldwide. Accumulating evidence has suggested that inflammation participates in the progression and pathogenesis of epilepsy. During inflammation, a cytosolic multimolecular complex called the "inflammasome" is activated, driving the innate immune response. This inflammatory pathway by sensing various pathogens and molecules from damaged cells and then activation of caspase-1 enzyme initiates inflammatory responses. Activated caspase-1 leads to the proteolytic cleavage of the pro-inflammatory cytokines, interleukin-1β (IL-1β) and interleukin-18 (IL-18), and also induction of an inflammatory programmed cell death termed pyroptosis. NLR family pyrin domain-containing 1 (NLRP1) and NLRP3 are the two best-characterized inflammasome members, and both basic and clinical research has reported their activation during epilepsy. This overview is intended to summarize the current literature concerning NLRP1 and NLRP3 inflammasome activation and epilepsy.

The NLRP3 inflammasome mediates the production of proinflammatory cytokines and initiates inflammatory cell death. Although NLRP3 is essential for innate immunity, aberrant NLRP3 inflammasome activation contributes to a wide variety of inflammatory diseases. Understanding the pathways that control NLRP3 activation will help develop strategies to treat these diseases. Here we identify WNK1 as a negative regulator of the NLRP3 inflammasome. Macrophages deficient in WNK1 protein or kinase activity have increased NLRP3 activation and pyroptosis compared with control macrophages. Mice with conditional knockout of WNK1 in macrophages have increased IL-1β production in response to NLRP3 stimulation compared with control mice. Mechanistically, WNK1 tempers NLRP3 activation by balancing intracellular Cl– and K+ concentrations during NLRP3 activation. Collectively, this work shows that the WNK1 pathway has a critical function in suppressing NLRP3 activation and suggests that pharmacological inhibition of this pathway to treat hypertension might have negative clinical implications., The serine/threonine kinase WNK1 is an inhibitor of chloride efflux. Here the authors show that this inhibition is a means of negatively regulating the activation of the NLRP3 inflammasome in macrophages, leading to reduced inflammatory responses.

Inflammasomes are protein complexes of the innate immune system that initiate inflammation in response to either exogenous pathogens or endogenous danger signals. Inflammasome multiprotein complexes are composed of three parts: a sensor protein, an adaptor, and pro-caspase-1. Activation of the inflammasome leads to the activation of caspase-1, which cleaves pro-inflammatory cytokines such as IL-1β and IL-18, leading to pyroptosis. Effectors of the inflammasome not only provide protection against infectious pathogens, but also mediate control over sterile insults. Aberrant inflammasome signaling has been implicated in the development of cardiovascular and metabolic diseases, cancer, and neurodegenerative disorders. Here, we review the role of the inflammasome as a double-edged sword in various diseases, and the outcomes can be either good or bad depending on the disease, as well as the genetic background. We highlight inflammasome memory and the two-shot activation process. We also propose the M- and N-type inflammation model, and discuss how the inflammasome pathway may be targeted for the development of novel therapy.

Background Helicobacter pylori (H. pylori) is a common pathogen in development of peptic ulcers with pyroptosis. Rabeprazole, a critical component of standard triple therapy, has been widely used as the first-line regimen for H. pylori infectious treatment. The aim of this study to explore the function of Rabeprazole on cell pyroptosis in vitro. Methods The clinical sample from patients diagnosed with or without H. pylori-infection were collected to analyze by Immunohistochemistry (IHC). Real-time quantitative PCR (qPCR), western blot (WB) and enzyme linked immunosorbent assay (Elisa) were performed to analyze the effect of Rabeprazole on cell pyroptosis, including LDH, IL-1β and IL-18. Results In this study, we showed that Rabeprazole regulated a phenomenon of cell pyroptosis as confirmed by lactate dehydrogenase (LDH) assay. Further results showed that Rabeprazole inhibited cell pyroptosis in gastric epithelial cells by alleviating GSDMD-executed pyroptosis, leading to decrease IL-1β and IL-18 mature and secretion, which is attributed to NLRP3 inflammasome activation inhibition. Further analysis showed that ASC, NLRP3 and Caspase-1, was significantly repressed in response to Rabeprazole stimulation, resulting in decreasing cleaved-caspase-1 expression. Most important, NLRP3 and GSDMD is significantly increased in gastric tissue of patients with H. pylori infection. Conclusion These findings revealed a critical role of Rabeprazole in cell pyroptosis in patients with H. pylori infection, suggesting that targeting cell pyroptosis is an alternative strategy in improving H. pylori treatment.

Sepsis is a life-threatening cascading systemic inflammatory response syndrome on account of serve infection. In inflamed tissues, activated macrophages generate large amounts of inflammatory cytokines reactive species, and are exposed to the damaging effects of reactive species. However, comparing with necroptosis and pyroptosis, so far, there are few studies focusing on the overproduction-related cell death, such as parthanatos in macrophage during sepsis. In LPS-treated macrophage, we observed PARP-1 activation, PAR formation and AIF translocation. All these phenomena could be inhibited by both erlotinib and 3-AB, indicating the presence of parthanatos in endotoxemia. We further found that LPS induced the increase of cell surface TLR4 expression responsible for the production of ROS and subsequent parthanatos in endotoxemia. All these results shed a new light on how TLR4 regulating the activation of PARP-1 by LPS in macrophage.

Significance: Kidney diseases remain a worldwide public health problem resulting in millions of deaths each year; they are characterized by progressive destruction of renal function by sustained inflammation. Pyroptosis is a lytic type of programmed cell death involved in inflammation, as well as a key fibrotic mechanism that is critical in the development of kidney pathology. Pyroptosis is induced by the cleavage of Gasdermins by various caspases and is executed by the insertion of the N-terminal fragment of cleaved Gasdermins into the plasma membrane, creating oligomeric pores and allowing the release of diverse proinflammatory products into the extracellular space. Inflammasomes are multiprotein complexes leading to the activation of caspase-1, which will cleave Gasdermin D, releasing several proinflammatory cytokines; this results in the initiation and amplification of the inflammatory response. Recent Advances: The efficacy of Gasdermin D cleavage is reduced by a change in the redox balance. Recently, several studies have shown that the attenuation of reactive oxygen species (ROS) production induced by antioxidant pathways results in a reduction of renal pyroptosis. In this review, we discuss the role of pyroptosis in the pathogenesis of chronic kidney disease (CKD) and acute kidney disease; summarize the clinical outcomes and different molecular mechanisms leading to Gasdermin activation; and examine studies about the capacity of antioxidants, particularly Nrf2 activators, to ameliorate Gasdermin activity. Future Directions: We illustrate the potential influence of the deregulation of redox balance on inflammasome activity and pyroptosis as a novel therapeutic approach for the treatment of kidney diseases. Antioxid. Redox Signal. 35, 40-60.

Inflammasomes have emerged as context-dependent regulators of inflammation and protective immunity in vertebrates. Depending on the cell type and stimulus, inflammasome activities lead to interleukin (IL)-1 release from living (hyperactive) or dead (pyroptotic) cells. Herein, we review the mechanisms by which inflammasomes can impact CD8+ T cell-mediated antitumor immunity. We describe recent work demonstrating the differential impact of pyroptosis in cancer cells and dendritic cells (DCs) on antitumor immunity. We further highlight the surprising ability of inflammasomes within hyperactive DCs to facilitate the use of tumor lysates as immunogens, promoting CD8+ T cell-mediated antitumor responses. These context-dependent roles of inflammasomes in living and dead cells offer much opportunity for future research and should inform discussions of next-generation immunotherapy development.

When surveying the current literature on COVID-19, the “cytokine storm” is considered to be pathogenetically involved in its severe outcomes such as acute respiratory distress syndrome, systemic inflammatory response syndrome, and eventually multiple organ failure. In this review, the similar role of DAMPs is addressed, that is, of those molecules, which operate upstream of the inflammatory pathway by activating those cells, which ultimately release the cytokines. Given the still limited reports on their role in COVID-19, the emerging topic is extended to respiratory viral infections with focus on influenza. At first, a brief introduction is given on the function of various classes of activating DAMPs and counterbalancing suppressing DAMPs (SAMPs) in initiating controlled inflammation-promoting and inflammation-resolving defense responses upon infectious and sterile insults. It is stressed that the excessive emission of DAMPs upon severe injury uncovers their fateful property in triggering dysregulated life-threatening hyperinflammatory responses. Such a scenario may happen when the viral load is too high, for example, in the respiratory tract, “forcing” many virus-infected host cells to decide to commit “suicidal” regulated cell death (e.g., necroptosis, pyroptosis) associated with release of large amounts of DAMPs: an important topic of this review. Ironically, although the aim of this “suicidal” cell death is to save and restore organismal homeostasis, the intrinsic release of excessive amounts of DAMPs leads to those dysregulated hyperinflammatory responses—as typically involved in the pathogenesis of acute respiratory distress syndrome and systemic inflammatory response syndrome in respiratory viral infections. Consequently, as briefly outlined in this review, these molecules can be considered valuable diagnostic and prognostic biomarkers to monitor and evaluate the course of the viral disorder, in particular, to grasp the eventual transition precociously from a controlled defense response as observed in mild/moderate cases to a dysregulated life-threatening hyperinflammatory response as seen, for example, in severe/fatal COVID-19. Moreover, the pathogenetic involvement of these molecules qualifies them as relevant future therapeutic targets to prevent severe/ fatal outcomes. Finally, a theory is presented proposing that the superimposition of coronavirus-induced DAMPs with non-virus-induced DAMPs from other origins such as air pollution or high age may contribute to severe and fatal courses of coronavirus pneumonia.

Myocardial injury and cardiovascular dysfunction are serious consequences of sepsis and contribute to high mortality. Currently, the pathogenesis of myocardial injury in sepsis is still unclear, and therapeutic approaches are limited. In this study, we investigated the protective effect of emodin on septic myocardial injury and the underlying mechanism. Lipopolysaccharide (LPS)-induced C57BL/6 mice and cardiomyocytes were used as models of sepsis in vivo and in vitro, respectively. The results showed that emodin alleviated cardiac dysfunction, myocardial injury and improved survival rate in LPS-induced septic mice. Emodin attenuated the levels of inflammatory cytokines and cardiac inflammation induced by LPS. Emodin reduced NOD-like receptor protein 3 (NLRP3) and Gasdermin D (GSDMD) expression in the heart tissue of LPS-induced septic mice. In vitro, emodin alleviated LPS-induced cell injury and inflammation in cardiomyocytes by inhibiting NLRP3 inflammasome activation. In addition, an NLRP3 inhibitor was used to further confirm the function of the NLRP3 inflammasome in LPS-induced myocardial injury. Taken together, our findings suggest that emodin improves LPS-induced myocardial injury and cardiac dysfunction by alleviating the inflammatory response and cardiomyocyte pyroptosis by inhibiting NLRP3 inflammasome activation, which provides a feasible strategy for preventing and treating myocardial injury in sepsis.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, a class of systemic autoimmune diseases, results in damage of various critical organs including kidneys, lungs, eyes, and nervous system. MicroRNA-340-5p was confirmed to be downregulated in autoimmune pathogenesis. However, the role of miR-340-5p remains unknown in ANCA-induced glomerulonephritis (GN). The current study aimed to explore the role of miR-340-5p in ANCA-induced GN. The animal models of ANCA-induced GN was established by experimental autoimmune vasculitis (EAV) operation. The primary glomerular endothelial cells (PGEnCs) were treated with anti-myeloperoxidase (anti-MPO) to mimic cell injury in vitro. The renal function was analysed by measuring serum creatinine, blood urea nitrogen, urine blood, urine protein and urine leukocytes. The levels of RNA and proteins were examined by RT-qPCR and western blot analysis, respectively. The binding capacity between miR-340-5p and KDM4C was detected by luciferase reporter assay. Cell apoptosis was analysed by flow cytometry in vitro. Cell viability was determined by CCK-8 assay. The cleaved caspase-3 activity was analysed by immunofluorescent assay. Cell inflammation was measured by western blot. Cell procoagulant activity was assessed by FXa generation assay. The histological changes of renal tissues were assessed by Haematoxylin and eosin (H&E) staining assay. The correlation between miR-340-5p and KDM4C level (or content of TNF-α and IL-6) was analysed by Pearson correlation analysis. The injection of anti-MPO IgG induced a significant elevation of Serum creatinine and blood urea nitrogen in serum, as well as urine blood, urine protein and urine leukocytes. Importantly, KDM4C was downregulated in model group. In mechanism, we identified that miR-340-5p bound with KDM4C 3'untranslated region (UTR), negatively regulated KDM4C in endothelial cells and negatively correlated with KDM4C in serum of GN rats. In function, we found that miR-340-5p promoted B cell activation and proliferation by downregulating KDM4C. The in vitro assays showed that the decrease of cell viability induced by anti-MPO was reversed by miR-340-5p overexpression, and further reduced by KDM4C overexpression. Inversely, the suppressive effects of miR-340-5p mimics on cell apoptosis, cleaved caspase-3 activity, inflammatory response and pro-coagulation were countervailed by KDM4C overexpression in anti-MPO-treated cells. The in vivo assays validated that miR-340-5p overexpression mitigated the impairment of renal function, and histological changes induced by anti-MPO IgG injection in model group. Finally, we found the negative correlation between miR-340-5p and TNF-α (or IL-6) content in serum of GN rats. In conclusion, we found that miR-340-5p inhibited endothelial apoptosis and inflammatory response by targeting KDM4C in ANCA-mediated GN through activation of B cells, implying a potential novel insight for treatment of ANCA-mediated GN.

Pyroptosis is a type of programmed cell death mediated by a multiprotein complex called the inflammasome through the pro-inflammatory activity of gasdermin-D. Aim To recognize the final biological product that leads to pore formation in the cell membrane, lysis, pro-inflammatory cytokines release, and the establishment of an immune response. Methods An exhaustive search engine investigation of an elevated immune response can induce a sustained inflammation that directly links this mechanism to non-alcoholic fatty liver disease and its progression to non-alcoholic steatohepatitis. Results Clinical studies and systematic reviews suggest that gasdermin-D is a critical molecule between the immune response and the disease manifestation, which could be considered a therapeutic target for highly prevalent diseases characterized by presenting perpetuated inflammatory processes. Conclusion Both basic and clinical research show evidence on the expression and regulation of the inflammasome-gasdermina-D-piroptosis trinomial for the progression of nonalcoholic fatty liver disease to nonalcoholic steatohepatitis.

Context: Hypoxia-induced injury is a classic symptom of obstructive sleep apnea hypopnea syndrome (OSAHS), which is a risk factor of various diseases, such as hypertension, heart failure and stroke. However, there is no effective therapy for hypoxia-induced injury or OSAHS due to the elusive mechanism involved. Objective: This study aimed to assess the effects of paeoniflorin on hypoxia-induced injury and explore the underlying mechanism. Materials and methods: Hypoxic models of SD rats and CTX-TNA2 cells were used to assess the effect of paeoniflorin, and the expressions of hif1a, miR-210, caspase1 and GSDMD were detected using western blots and RT-PCR. Plasmid transfection was performed to explore the role of miR-210 in the effect of paeoniflorin. Results: Firstly, we confirmed that hypoxia induced severe neuronal injury and an enhancement of inflammation in the rat brain, with elevated expression of caspase1, IL1b and IL18. In addition, the results showed an activation of astrocytes and an increased level of pyroptosis under hypoxic conditions, which suggested a critical role of pyroptosis in hypoxiainduced injury of the brain. Furthermore, we found that compared with the controls, paeoniflorin treatment improved hypoxia-induced pyroptosis in astrocytes. Moreover, we detected the activation of hif1a/miR-210 signaling in the effects of paeoniflorin on astrocytes. As expected, the expression of hif1a and miR-210 was significantly upregulated in astrocytes when exposed to hypoxia, while paeoniflorin treatment reversed these enhancements. After transfection of miR-210 mimics, the attenuation of pyroptosis induced by paeoniflorin was suppressed, which was accompanied by an increase of ROS levels, as well as LDH release, indicating a critical role of miR-210 in pyroptosis in astrocytes. Conclusions: Our findings demonstrated that paeoniflorin improved hypoxia-induced pyroptosis in astrocytes via depressing hif1a/miR-210/caspase1/GSDMD signaling, providing robust evidence for the treatment of hypoxic injury and OSAHS.HighlightsHypoxia induces severe injury and inflammatory response in the rat brain;Hypoxia enhanced pyroptotic level and led to an activation of astrocytes.;Paeoniflorin alleviates hypoxia-induced pyroptosis in astrocytes;Transfection of miR-210 mimics suppressed the effects of paeoniflorin on hypoxia-induced pyroptosis in astrocytes. Hypoxia induces severe injury and inflammatory response in the rat brain; Hypoxia enhanced pyroptotic level and led to an activation of astrocytes.; Paeoniflorin alleviates hypoxia-induced pyroptosis in astrocytes; Transfection of miR-210 mimics suppressed the effects of paeoniflorin on hypoxia-induced pyroptosis in astrocytes.

Diabetes is emerging as a severe global health problem that threatens health and increases socioeconomic burden. Periodontal impairment is one of its well-recognized complications. The destruction of the periodontal defense barrier makes it easier for periodontal pathogens to invade in, triggering a greater inflammatory response, and causing secondary impairment. Macrophages are the major immune cells in periodontium, forming the frontier line of local innate immune barrier. Here, we explored the periodontal impairments and functional changes of macrophages under the diabetic and aging conditions. Besides, we further explored the molecular mechanism of how hyperglycemia and aging contribute to this pathogenesis. To test this, we used young and aged mice to build diabetic mice, and metformin treatment was applied to a group of them. We demonstrated that under hyperglycemia conditions, macrophage functions, such as inflammatory cytokines secretion, phagocytosis, chemotaxis, and immune response, were disturbed. Simultaneously, this condition elevated the local senescent cell burden and induced secretion of senescence-associated secretory phenotype. Meanwhile, we found that expressions of Gasdermin D (GSDMD) and caspase-1 were up-regulated in diabetic conditions, suggesting that the local senescent burden and systemic proinflammatory state during diabetes were accompanied by the initiation of pyroptosis. Furthermore, we found that the changes in aged condition were similar to those in diabetes, suggesting a hyperglycemia-induced pre-aging state. In addition, we show that metformin treatment alleviated and remarkably reversed these functional abnormalities. Our data demonstrated that diabetes initiated macrophage pyroptosis, which further triggered macrophage function impairments and gingival destructions. This pathogenesis could be reversed by metformin.

Inflammasomes are molecular machines that carry out inflammatory responses on challenges by pathogens and endogenous dangers. Dysregulation of inflammasome assembly and regulation is associated with numerous human diseases from autoimmunity to cancer. In recent years, significant advances have been made in understanding the mechanism of inflammasome signaling using structural approaches. Here, we review inflammasomes formed by the NLRP1, NLRP3, and NLRC4 sensors, which are well characterized structurally, and discuss the structural and functional diversity among them.

Listeria monocytogenes is a food-borne pathogen responsible for neurolisteriosis, which is potentially lethal in immunocompromised individuals. Microglia are the main target cells for L. monocytogenes in central nervous system (CNS). However, the precise mechanisms by which they trigger neuroinflammatory processes remain unknown. The BV2 microglial cell line and a murine model of L. monocytogenes infection were used for experiments in this study. Listeria monocytogenes induced pyroptosis and nucleotide binding and oligomerization, leucine-rich repeat, pyrin domain-containing 3 (NLRP3) inflammasome activation in BV2. Pharmacological inhibition of the NLRP3 inflammasome attenuated L. monocytogenes-induced pyroptosis. Moreover, inhibition of nuclear factor kappa-B (NF-κB) and extracellular regulated protein kinases (ERK) pathways induced a decrease in caspase1 activation and mature IL-1β-17 secretion. Our collective findings support critical involvement of the NLRP3 inflammasome in L. monocytogenes-induced neuroinflammation and, to an extent, ROS production. In addition, ERK and NF-κB signaling play an important role in activation of the NLRP3 inflammasome, both in vitro and in vivo.

Inflammasomes are cytosolic multiprotein complexes that crucially contribute to host defense against pathogens but are also involved in the pathogenesis of autoinflammatory diseases. Inflammasome formation leads to activation of effector caspases (caspase-1, 4, 5, or 11), the proteolytic maturation of IL-1β and IL-18 as well as cleavage of the pore-forming protein Gasdermin D. Dendritic cells are major regulators of immune responses as they bridge innate and adaptive immunity. We here summarize the current knowledge on inflammasome expression and formation in murine bone marrow-, human monocyte-derived as well as murine and human primary dendritic cells. Further, we discuss both, the beneficial and detrimental, involvement of inflammasome activation in dendritic cells in cancer, infections, and autoimmune diseases. As inflammasome activation is typically accompanied by Gasdermin d -mediated pyroptosis, which is an inflammatory form of programmed cell death, inflammasome formation in dendritic cells seems ill-advised. Therefore, we propose that hyperactivation, which is inflammasome activation without the induction of pyroptosis, may be a general model of inflammasome activation in dendritic cells to enhance Th1, Th17 as well as cytotoxic T cell responses.

Pyroptosis is a kind of pro-inflammatory cell death. Compared with autophagy and apoptosis, pyroptosis has unique characteristics in morphology and mechanism. Specifically, pyroptosis is a kind of cell lysis mediated by the Gasdermin family, releases inflammatory cytokines IL-1β and IL-18. There are three different forms of mechanism, which are caspase-1-mediated, caspase-4/5/11-mediated and caspase-3-mediated. A large number of studies have proved that pyroptosis is closely related to cardiovascular disease. This paper reviewed the recent progress in the related research on pyroptosis and myocardial infarction, ischemia-reperfusion, atherosclerosis, diabetic cardiomyopathy, arrhythmia, heart failure hypertension and Kawasaki disease. Therefore, we believe that pyroptosis may be a new therapeutic target in the cardiovascular field.

The death of endocrine cells is involved in type 1 diabetes mellitus, autoimmunity, adrenopause and hypogonadotropism. Insights from research on basic cell death have revealed that most pathophysiologically important cell death is necrotic in nature, whereas regular metabolism is maintained by apoptosis programmes. Necrosis is defined as cell death by plasma membrane rupture, which allows the release of damage-associated molecular patterns that trigger an immune response referred to as necroinflammation. Regulated necrosis comes in different forms, such as necroptosis, pyroptosis and ferroptosis. In this Perspective, with a focus on the endocrine environment, we introduce these cell death pathways and discuss the specific consequences of regulated necrosis. Given that clinical trials of necrostatins for the treatment of autoimmune conditions have already been initiated, we highlight the therapeutic potential of such novel therapeutic approaches that, in our opinion, should be tested in endocrine disorders in the future., Studies have shown that the three pathways of regulated necrosis, namely necroptosis, pyroptosis and ferroptosis, can be therapeutically targeted. This Perspective summarizes existing data on the newly characterized cell death pathways in endocrine disorders.

Lung adenocarcinoma (LUAD) remains the most common deadly disease and has a poor prognosis. Pyroptosis could regulate tumour cell proliferation, invasion, and metastasis, thereby affecting the prognosis of cancer patients. However, the role of pyroptosis-related genes (PRGs) in LUAD remains unclear. In our study, comprehensive bioinformatics analysis was performed to construct a prognostic gene model and ceRNA network. The correlations between PRGs and tumour-immune infiltration, tumour mutation burden, and microsatellite instability were evaluated using Pearson’s correlation analysis. A total of 23 PRGs were upregulated or downregulated in LUAD. The genetic mutation variation landscape of PRG in LUAD was also summarised. Functional enrichment analysis revealed that these 33 PRGs were mainly involved in pyroptosis, the NOD-like receptor signalling pathway, and the Toll-like receptor signalling pathway. Prognosis analysis indicated a poor survival rate in LUAD patients with low expression of NLRP7, NLRP1, NLRP2, and NOD1 and high CASP6 expression. A prognostic PRG model constructed using the above five prognostic genes could predict the overall survival of LUAD patients with medium-to-high accuracy. Significant correlation was observed between prognostic PRGs and immune-cell infiltration, tumour mutation burden, and microsatellite instability. A ceRNA network was constructed to identify a lncRNA KCNQ1OT1/miR-335-5p/NLRP1/NLRP7 regulatory axis in LUAD. In conclusion, we performed a comprehensive bioinformatics analysis and identified a prognostic PRG signature containing five genes (NLRP7, NLRP1, NLRP2, NOD1, and CASP6) for LUAD patients. Our results also identified a lncRNA KCNQ1OT1/miR-335-5p/NLRP1/NLRP7 regulatory axis, which may also play an important role in the progression of LUAD. Further study needs to be conducted to verify this result.

Intervertebral disc degeneration (IDD) is a major cause of lower back pain (LBP), a condition that causes a heavy economic burden globally. The production of cytokines, including interleukin (IL)-1β and tumor necrosis factor (TNF) α, is increased in the degenerating intervertebral disc. Thioredoxin-interacting protein (TXNIP) participates in NLRP3 inflammasome-dependent pyroptosis in liver. Therefore, we hypothesized that TXNIP maypromote pyroptosis via NLRP3/Caspase-1/IL-1β signaling pathway in nucleus pulposus (NP) cell. This study examined the effects of TXNIP on IDD, explored the underlying mechanisms of action and find Morin which is the inhibitor of TXNIP can attenuates pyroptosis of nucleus pulposus cells and ameliorates intervertebral disc degeneration. Our findings indicate that TXNIP promote pyroptosis via NLRP3/Caspase-1/IL-1β signaling pathway in NP cell. Morin considerably inhibited the TXNIP/NLRP3/Caspase-1 signaling pathway in vitro. In vivo. Our data show that TXNIP can aggravates intervertebral disc degeneration and morin may be a useful therapeutic agent for IDD.

Sepsis and septic shock driven by microbial infections are still among the most challenging health problems, causing 11 million deaths worldwide every year. How does the host's response to pathogen infections effectively restore homeostasis instead of precipitating pathogenic and potentially fatal feedforward reactions? Recently, there have been significant new advances in our understanding of the interface between mammalian immunity and coagulation ('immunocoagulation') and its impact on sepsis. In particular, the release and activation of F3 (the main initiator of coagulation) from and on myeloid or epithelial cells is facilitated by activating inflammasomes and consequent gasdermin D (GSDMD)-mediated pyroptosis, coupled to signaling via high mobility group box 1 (HMGB1), stimulator of interferon response CGAMP interactor 1 (STING1), or sequestosome 1 (SQSTM1). Pharmacological modulation of the immunocoagulation pathways emerge as novel and potential therapeutic strategies for sepsis.

Intervertebral disc degeneration (IVDD) is one of the leading causes of low back pain and one of the most common health problems in the world. The nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing-3 (NLRP3) inflammasome, as a pattern recognition receptor, has been shown to be associated with the pathological processes of many diseases in recent years. With the exploration of the mechanism of IVDD, recent studies have shown that activation of the NLRP3 inflammasome is associated with intervertebral disc (IVD) inflammation, pyroptosis, extracellular matrix degradation and apoptosis of IVD cells. In this review, we summarize the structural characteristics of NLRP3 inflammasome and the activation signalling mechanisms. We also describe the role of the NLRP3 inflammasome in the pathological process of IVDD and the application of the targeting the NLRP3 inflammasome in IVDD treatment.

Innate immune responses are tightly regulated by various pathways to control infections and maintain homeostasis. One of these pathways, the inflammasome pathway, activates a family of cysteine proteases called inflammatory caspases. They orchestrate an immune response by cleaving specific cellular substrates. Canonical inflammasomes activate caspase-1, whereas non-canonical inflammasomes activate caspase-4 and -5 in humans and caspase-11 in mice. Caspases are highly specific enzymes that select their substrates through diverse mechanisms. During inflammation, caspase activity is responsible for the secretion of inflammatory cytokines and the execution of a form of lytic and inflammatory cell death called pyroptosis. This review aims to bring together our current knowledge of the biochemical processes behind inflammatory caspase activation, substrate specificity, and substrate signalling.

Chemotherapy drugs usually inhibit tumor cell growth through the apoptosis pathway. However, tumor cells become resistant to chemotherapy drugs by evading apoptosis. It is necessary to find new ways to inhibit tumor growth through other types of death. Pyroptosis is a recently identified inflammatory cell death that plays an important role in a variety of diseases, including cancer. In this review, we will systematically review recent progress in the pyroptosis signaling pathway, the role of inflammasomes in cancer in the context of pyroptosis, the role of gasdermin proteins in cancer and the role of pyroptosis in tumor immunity. We will also discuss the application of the pyroptosis pathway in clinical studies. Finally, we hope to provide new strategies for pyroptosis in the clinic.

Background Our previous study identified elevated expression of the P2X7 receptor (P2X7R) in colorectal cancer (CRC) patients, suggesting the receptor is a target for predicting poor disease prognosis. A438079 is a highly selective P2X7R antagonist, however, no studies have identified A438079 effects and mechanisms toward the biological behavior of CRC cells, and its therapeutic in vivo potential in CRC nude mice. Methods The CRC cell lines, HCT-116 and SW620 were treated with 10 μM A438079, after which proliferation, migration, invasion, and apoptosis were assessed. SW620 cell xenografted BALB/c nude male mice were randomly divided into control, 5-FU, and A438079 groups. Mouse weight and tumor dimensions were also measured every two days. Furthermore, the expression of apoptosis related indicators (P2X7R, Bcl-2, Bax, caspase9, cleaved caspase9, caspase3, and cleaved caspase3) and pyroptosis related indicators (NLRP3, ASC, cleaved caspase1, and interleukin (IL)-β) were investigated in vitro and in vivo. Results A438079 inhibited HCT-116 and SW620 cell proliferation, invasion and migration, and inhibited the growth of CRC xenografts in nude mice. A438079 promoted apoptosis via the Bcl-2/caspase9/caspase3 pathway and inhibited pyroptosis through the NLRP3/caspase1 pathway by inhibiting P2X7R in vitro and in vivo. Conclusions We preliminarily confirmed the therapeutic potential of A438079 toward CRC, and we provide a sound theoretical basis for A438079 as a new drug for the clinical treatment of CRC.

Muscle segment homeobox 2 (MSX2) has been confirmed to be involved in the regulation of early tooth development. However, the role of MSX2 has not been fully elucidated in enamel development. To research the functions of MSX2 in enamel formation, we used a Msx2 −/− (KO) mouse model with no full Msx2 gene. In the present study, the dental appearance and enamel microstructure were detected by scanning electron microscopy and micro‐computed tomography. The results showed that the absence of Msx2 resulted in enamel defects, leading to severe tooth wear in KO mice. To further investigate the mechanism behind the phenotype, we performed detailed histological analyses of the enamel organ in KO mice. We discovered that ameloblasts without Msx2 could secrete a small amount of enamel matrix protein in the early stage. However, the enamel epithelium occurred squamous epithelial hyperplasia and partial keratinization in the enamel organ during subsequent developmental stages. Ameloblasts depolarized and underwent pyroptosis. Overall, during the development of enamel, MSX2 affects the formation of enamel by regulating the function of epithelial cells in the enamel organ.

The circRNAs–miRNAs–mRNAs competing endogenous RNA (ceRNA) networks involve in regulating the development of various inflammation-associated diseases, including allergic rhinitis (AR), and the present study aimed to identify novel AR-associated ceRNA networks. The mRNA and protein levels of the associated genes were, respectively, examined by real-time qPCR and western blot analysis. The targeting sites in miR-556-5p and NLRP3 were validated by performing dual-luciferase reporter gene system assay. ELISA was used to measure inflammatory cytokines secretion, and CCK-8 assay was conducted to determine cell proliferation. Here, we first identified a hsa_circ_0000520/miR-556-5p/NLRP3 signaling cascade triggered epithelium pyroptosis and inflammation to regulate the development of AR in cellular and mice models. Specifically, the pyroptosis-associated biomarkers (NLRP3, ASC, IL-1β and IL-18) and pro-inflammatory cytokines (OVA-specific IgE, TNF-α, IL-4 and IL-5) were upregulated in the nasal subjects collected from AR patients and ovalbumin (OVA)-induced AR mice models, compared to their normal counterparts. Next, using the ceRNA networks analysis software, we screened out a hsa_circ_0000520/miR-556-5p axis that potentially regulated NLRP3 in the human nasal epithelial cell line. Mechanistically, miR-556-5p targeted both hsa_circ_0000520 and 3′ untranslated region (3′UTR) of NLRP3, and knock-down of hsa_circ_0000520 inactivated NLRP3-mediated epithelium pyroptosis through miR-556-5p in a ceRNA-dependent manner. Furthermore, we proved that both hsa_circ_0000520 ablation and miR-556-5p overexpression suppressed NLRP3-mediated cell pyroptosis to attenuate AR in mice models. Taken together, we evidenced that targeting the hsa_circ_0000520/miR-556-5p/NLRP3 signaling pathway was a novel AQ1strategy to ameliorate AR progression; however, future clinical data are still required to validate our preliminary results.

A steatotic liver is increasingly vulnerable to ischemia reperfusion injury (IRI), and the underlying mechanisms are incompletely defined. Caspases are endo-proteases, which provide critical regulatory connections between cell death and inflammation. Caspase 1 is driven by inflammasomes which are key signaling platforms, that detect sterile stressors (DAMPs), releasing the highly pro-inflammatory cytokine interleukin IL-8 and IL-1β. To delineate the involvement of Caspase 1 and 11 in hepatocellular injury in steatotic liver undergoing IRI. Male C57BL6/Wild Type and Caspase 1Null, Caspase 11−/− and Caspase 1−/−/11−/− mice were fed a high fat diet (HFD) for 12 weeks. These mice were subjected to 40 min of ischemia followed by 2–24 h of reperfusion. Hepatocellular injury was assessed by histopathologic injury scoring, serum ALT and propidium iodide (PI) uptake, mRNA levels of Caspase 1, IL-1β by RT PCR, Caspase 1 activity assay and Caspase 1. Specific Caspase 1, inhibitor experiments were carried out. All groups gained similar body weight after a 12-week HFD. Cleaved Caspase 1 protein levels, Caspase 1 mRNA levels were significantly higher in steatotic liver undergoing IRI. Executor of pyroptosis cleaved GSDMD levels were higher in HFD fed mouse compared to lean. In addition, genetic deletion of Caspase 1, Casp1Null mouse expressing Caspase-11 and Caspase 1/11 double knock out demonstrated significant reduction in serum ALT (p

Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster. The treatment of PHN remains a challenge for clinical pain management. The present study investigated the P2X7 receptor antagonist brilliant blue G (BBG) whether inhibits endoplasmic reticulum stress and pyroptosis (a necrotic form of cell death) and alleviates PHN. Varicella zoster virus (VZV)-infected CV-1 cells were used to induce PHN model. Mechanical paw withdrawal thresholds were measured using an ascending series of von Frey filaments. Immunohistochemistry was used to detect the expression of P2X7R in nerve tissues. Western blot was used to determine the expression of endoplasmic reticulum (ER) stress and pyroptosis-related molecules. The expression of IL-1β and IL-18 in tissue homogenate was detected by ELISA. The PHN rat has the lower paw withdrawal threshold, but higher expression of P2X7 in nerve tissues. And, endoplasmic reticulum stress was activated and pyroptosis was increased in PHN rats. BBG can decrease pain thresholds and reduce ER stress and pyroptosis in PHN rats. In addition, ER stress activator tunicamycin (TM) can reverse the effect of BBG on the paw withdrawal thresholds, endoplasmic reticulum stress, and pyroptosis. Therefore, P2X7 receptor antagonist BBG alleviates PHN by activating ER stress and reducing pyroptosis.

The presence of hepatic steatosis and inflammation is increasingly associated with both metabolic and alcohol-related liver conditions. Both are on the increase globally and, apart from liver transplantation, there are no licensed therapies that target the full complement of disease features. The presence of some shared pathogenic mechanisms and histological features in NAFLD and ALD suggests that it may be possible to develop markers for prognostication or staging, or indeed new therapeutic tools to treat both conditions. One such example of an approach exists in the form of the NACHT-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome pathway. Activation of the NLRP3 inflammasome results in hepatocyte pyroptosis, persistence, and amplification of liver inflammation and activation of profibrogenic signaling cascades. Thus, targeting elements of the pathway in NAFLD and ALD may provide a tractable route to pharmacological therapy. In this review, we summarize the contribution of this inflammasome to disease and review the current options for therapy.

Stroke is a common disease with high mortality and disability worldwide. Different forms of cell deaths, including apoptosis and necrosis, occur in ischemic or hemorrhagic brain tissue, among which pyroptosis, a newly discovered inflammation-related programmed cell death, is generally divided into two main pathways, the canonical inflammasome pathway and the non-canonical inflammasome pathway. Caspase-mediated pyroptosis requires the assembly of inflammasomes such as NLRP3, which leads to the release of inflammatory cytokines IL-1β and IL-18 through the pores formed in the plasma membrane by GSDMD followed by neuroinflammation. Recently, pyroptosis and its relationship with inflammation have attracted more and more attention in the study of cerebral ischemia or hemorrhage. In addition, many inhibitors of pyroptosis targeting caspase, NLRP3, and the upstream pathway have been found to reduce brain tissue damage after stroke. In this review, we mainly introduce the pathology of stroke, the molecular mechanism, and process of pyroptosis, as well as the pivotal roles of pyroptosis in stroke, in order to provide new insights for the treatment of stroke.

Background and purpose Cardiac glycosides (CGs) inhibit the Na+ ,K+ -ATPase and are widely prescribed medicines for chronic heart failure and cardiac arrhythmias. Recently, CGs have been described to induce inflammasome activation and pyroptosis in human macrophages, suggesting a cytotoxicity that remains to be elucidated in tissues. Experimental approach To determine the cell type specificity of CG-mediated cytotoxicity, we used human primary monocyte-derived macrophages (hMDMs) and non-adherent peripheral blood cells isolated from healthy donors. Omental white adipose tissue (WAT) and stromal vascular fraction (SVF)-derived pre-adipocytes and adipocytes were isolated from obese patients undergoing bariatric surgery. All these primary cells/tissues were treated with nanomolar concentrations of ouabain (50nM, 100nM and 500nM) to investigate its degree of cytotoxicity and mechanisms leading to cell death. In WAT, we further explored the consequences of ouabain-mediated cytotoxicity by measuring insulin sensitivity, adipose tissue function and extracellular matrix (ECM) deposition ex vivo. Key results The ouabain-induced cell death is through pyroptosis and apoptosis, and more efficient in hMDMs compared to non-adherent PBMC populations. This selective cytotoxicity is dependent on K+ flux, as ouabain causes an intracellular depletion of K+ , while inducing accumulation of Na+ and Ca2+ levels. Consistently, the cell-death caused by these ion imbalances can be rescued by addition of potassium chloride in hMDMs. Remarkably, when WAT explants from obese patients are cultured with nanomolar concentrations of ouabain, this causes depletion of macrophages, down-regulation of type VI collagen levels, and amelioration of insulin sensitivity ex vivo. Conclusions and implications These results suggest that the usage of nanomolar concentration of CGs can be an attractive therapeutic avenue in metabolic syndrome characterised by pathogenic infiltration and activation of macrophages.

Autophagy is closely associated with cerebral ischaemia/reperfusion injury, but the underlying mechanisms are unknown. We investigated whether Spautin‐1 ameliorates cerebral ischaemia/reperfusion injury by inhibiting autophagy and whether its derived pyroptosis is involved in this process. We explored the mechanism of Spautin‐1 in cerebral ischaemia/reperfusion. To answer these questions, healthy male Sprague‐Dawley rats were exposed to middle cerebral artery occlusion for 60 minutes followed by reperfusion for 24 hours. We found that cerebral ischaemia/reperfusion increased the expression levels of autophagy and pyroptosis‐related proteins. Treatment with Spautin‐1 reduced the infarct size and water content and restored some neurological functions. In vitro experiments were performed using oxygen‐glucose deprivation/reoxygenation to model PC12 cells. The results showed that PC12 cells showed a significant decrease in cell viability and a significant increase in ROS and autophagy levels. Spautin‐1 treatment reduced autophagy and ROS accumulation and attenuated NLRP3 inflammasome‐dependent pyroptosis. However, these beneficial effects were greatly blocked by USP13 overexpression, which significantly counteracted the inhibition of autophagy and NLRP3 inflammasome‐dependent ferroptosis by Spautin‐1. Together, these results suggest that Spautin‐1 may ameliorate cerebral ischaemia‐reperfusion injury via the autophagy/pyroptosis pathway. Thus, inhibition of autophagy may be considered as a promising therapeutic approach for cerebral ischaemia‐reperfusion injury.

Apurinic/apyrimidinic endonuclease 1 (APE1) plays a critical role in the base excision repair (BER) pathway, which is responsible for the excision of apurinic sites (AP sites). In non-small cell lung cancer (NSCLC), APE1 is highly expressed and associated with poor patient prognosis. The suppression of APE1 could lead to the accumulation of unrepaired DNA damage in cells. Therefore, APE1 is viewed as an important marker of malignant tumors and could serve as a potent target for the development of antitumor drugs. In this study, we performed a high-throughput virtual screening of a small-molecule library using the three-dimensional structure of APE1 protein. Using the AP site cleavage assay and a cell survival assay, we identified a small molecular compound, NO.0449-0145, to act as an APE1 inhibitor. Treatment with NO.0449-0145 induced DNA damage, apoptosis, pyroptosis, and necroptosis in the NSCLC cell lines A549 and NCI-H460. This inhibitor was also able to impede cancer progression in an NCI-H460 mouse model. Moreover, NO.0449-0145 overcame both cisplatin- and erlotinib-resistance in NSCLC cell lines. These findings underscore the importance of APE1 as a therapeutic target in NSCLC and offer a paradigm for the development of small-molecule drugs that target key DNA repair proteins for the treatment of NSCLC and other cancers.

Excessive activation of inflammation in chondrocyte has been considered to be a major reason cause of cellular death and degeneration in osteoarthritis (OA) development. The NLRP3 inflammasome-mediated pyroptosis pathway is closely related to inflammation regulation. This research was conducted to confirm whether NLRP3 expression and activity are impacted in the development of OA and to detect the role of CY-09, a selective and direct inhibitor of NLRP3 in the in vitro and in vivo models of OA. Our findings corroborated that the expression of NLRP3 is stimulated in OA cartilage. CY-09 can maintain extracellular matrix (ECM) homeostasis and regulate inflammation in TNF-α treated chondrocytes via inhibition of NLRP3 inflammasome-mediated pyroptosis. Moreover, the chondrocyte protective effects of CY-09 were further confirmed in vivo in a DMM-induced OA model. In conclusion, our research indicates that experimental OA activated the NLRP3 activity, and pharmacological inhibition of NLRP3 inflammasome activation by CY-09 protects chondrocytes against inflammation and attenuates OA development.

Trichinella spiralis represents an effective treatment for autoimmune and inflammatory diseases. The effects of recombinant T. spiralis (TS) 53-kDa protein (rTsP53) on acute lung injury (ALI) remain unclear. Here, mice were divided randomly into a control group, LPS group, and rTsP53 + LPS group. ALI was induced in BALB/c mice by LPS (10 mg/kg) injected via the tail vein. rTsP53 (200 µl; 0.4 μg/μl) was injected subcutaneously three times at an interval of 5 d before inducing ALI in the rTsP53+LPS group. Lung pathological score, the ratio and markers of classic activated macrophages (M1) and alternatively activated macrophages (M2), cytokine profiles in alveolar lavage fluid, and pyroptosis protein expression in lung tissue were investigated. RTsP53 decreased lung pathological score. Furthermore, rTsP53 suppressed inflammation by increasing IL-4, IL-10, and IL-13. There was an increase in alveolar M2 macrophage numbers, with an increase in CD206 and arginase-1-positive cells and a decrease in alveolar M1 markers such as CD197 and iNOS. In addition, the polarization of M2 macrophages induced by rTsP53 treatment could alleviate ALI by suppressing lung pyroptosis. RTsP53 was identified as a potential agent for treating LPS-induced ALI via alleviating lung pyroptosis by promoting M2 macrophage polarization.

Although much is known about the gene mutations required to drive colorectal cancer (CRC) initiation, the tissue-specific selective microenvironments in which neoplasia arises remains less characterized. Here, we determined whether modulation of intestinal stem cell niche morphogens alone can exert a neoplasia-relevant selective pressure on normal colonic epithelium. Using adult stem cell-derived murine colonic epithelial organoids (colonoids), we employed a strategy of sustained withdrawal of EGF and EGFR inhibition to select for and expand survivors. EGFR-signaling-independent (iEGFR) colonoids emerged over rounds of selection and expansion. Colonoids derived from a mouse model of chronic mucosal injury showed an enhanced ability to adapt to EGFR inhibition. Whole-exome and transcriptomic analyses of iEGFR colonoids demonstrated acquisition of deleterious mutations and altered expression of genes implicated in EGF signaling, pyroptosis, and CRC. iEGFR colonoids acquired dysplasia-associated cytomorphologic changes, an increased proliferative rate, and the ability to survive independently of other required niche factors. These changes were accompanied by emergence of aneuploidy and chromosomal instability; further, the observed mitotic segregation errors were significantly associated with loss of interkinetic nuclear migration, a fundamental and dynamic process underlying intestinal epithelial homeostasis. This study provides key evidence that chromosomal instability and other phenotypes associated with neoplasia can be induced ex vivo via adaptation to EGF withdrawal in normal and stably euploid colonic epithelium, without introducing cancer-associated driver mutations. In addition, prior mucosal injury accelerates this evolutionary process.Key definitionsColonoids: adult stem cell-derived colonic epithelial organoidsiEGFR: in vitro selective conditions devoid of EGF (epidermal growth factor) and including an EGFR (EGF receptor) inhibitor 1iEGFR colonoids: colonoids tolerant to iEGFR culture conditions with growth and survival similar to unselected passage-matched controlsINM: Interkinetic nuclear migration

Ning Li,* Rui Xiong,* Ruyuan He, Bohao Liu, Bo Wang, Qing Geng Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, People’s Republic of China*These authors contributed equally to this workCorrespondence: Bo Wang; Qing GengDepartment of Thoracic Surgery, Renmin Hospital of Wuhan University, Jiefang Road 238, Wuhan, 430060, People’s Republic of ChinaEmail rmh_wb@whu.edu.cn; gengqingwhu@whu.edu.cnScope: Mangiferin (MF) is a natural phytopolyphenol, which displays potential pharmacological properties involving antibacterial, anti-inflammation, antioxidant and anti-tumor. However, little is known about the roles of MF in lung injury. The aim of this study is to demonstrate the modulatory effects and molecular mechanisms by which MF operates in sepsis-induced lung injury.Methods and Results: To examine the protective properties of MF, an in vivo model of lipopolysaccharide (LPS)-induced lung injury in mice and an in vitro model of LPS-treated J774A.1 cells were established, respectively. The results revealed that MF treatment significantly relieved LPS-induced pathological injury and inflammatory response in murine lung tissues. Meanwhile, MF treatment also inhibited nucleotide-binding oligomerization domain (NOD)-like receptor family, pyrin domain-containing protein 3 (NLRP3) inflammasome activation and pyroptosis induced by LPS. In macrophage-specific NLRP3 deficiency mice treated with LPS, MF showed little protective effects. NLRP3 overexpression by adenovirus could also offset the beneficial effects of MF in LPS-treated J774A.1 cells. Furthermore, we found that MF could suppress the expression of NLPR3 and pyroptosis of macrophages by inhibiting the nuclear translocation of the nuclear factor-κB (NF-κB) subunits P50 and P65.Conclusion: MF protects against lung injury and inflammatory response by inhibiting NLRP3 inflammasome activation in a NF-κB-dependent manner in macrophages, which provides a promising therapeutic candidate for the treatment of lung injury.Keywords: mangiferin, lung injury, NLRP3, P65

The toxin-producing bacterium Bacillus cereus is an important and neglected human pathogen and a common cause of food poisoning. Several toxins have been implicated in disease, including the pore-forming toxins hemolysin BL (HBL) and nonhemolytic enterotoxin (NHE). Recent work revealed that HBL binds to the mammalian surface receptors LITAF and CDIP1 and that both HBL and NHE induce potassium efflux and activate the NLRP3 inflammasome, leading to pyroptosis. These mammalian receptors, in part, contribute to inflammation and pathology. Other putative virulence factors of B. cereus include cytotoxin K, cereulide, metalloproteases, sphingomyelinase, and phospholipases. In this review, we highlight the latest progress in our understanding of B. cereus biology, epidemiology, and pathogenesis, and discuss potential new directions for research in this field.

Interleukin-1β (IL-1β) is activated by inflammasome-associated caspase-1 in rare autoinflammatory conditions and in a variety of other inflammatory diseases. Therefore, IL-1β activity must be fine-tuned to enable anti-microbial responses whilst limiting collateral damage. Here, we show that precursor IL-1β is rapidly turned over by the proteasome and this correlates with its decoration by K11-linked, K63-linked and K48-linked ubiquitin chains. The ubiquitylation of IL-1β is not just a degradation signal triggered by inflammasome priming and activating stimuli, but also limits IL-1β cleavage by caspase-1. IL-1β K133 is modified by ubiquitin and forms a salt bridge with IL-1β D129. Loss of IL-1β K133 ubiquitylation, or disruption of the K133:D129 electrostatic interaction, stabilizes IL-1β. Accordingly, Il1bK133R/K133R mice have increased levels of precursor IL-1β upon inflammasome priming and increased production of bioactive IL-1β, both in vitro and in response to LPS injection. These findings identify mechanisms that can limit IL-1β activity and safeguard against damaging inflammation.

Pyroptosis is mainly considered as a new pro-inflammatory mediated-programmed cell death. In addition, pyroptosis is described by gasdermin-induced pore formation on the membrane, cell swelling and rapid lysis, and several pro-inflammatory mediators interleukin-1β (IL-1β) and interleukin-18 (IL-18) release. Extensive studies have shown that pyroptosis is commonly involved by activating the caspase-1-dependent canonical pathway and caspase-4/5/11-dependent non-canonical pathway. However, pyroptosis facilitates local inflammation and inflammatory responses. Current researches have reported that pyroptosis promotes the progression of several diabetic complications. Emerging studies have suggested that some potential molecules targeting the pyroptosis and inflammasome signaling pathways could be a novel therapeutic avenue for managing and treating diabetes and its complications in the near future. Our narrative review concisely describes the possible mechanism of pyroptosis and its progressive understanding of the development of diabetic complications.

Nearly all animal cells contain proteins evolved to trigger the destruction of the cell in which they reside. The activation of these proteins occurs via sequential programs, and much effort has been expended in delineating the molecular mechanisms underlying the resulting processes of programmed cell death (PCD). These efforts have led to the definition of apoptosis as a form of nonimmunogenic PCD that is required for normal development and tissue homeostasis, and of pyroptosis and necroptosis as forms of PCD initiated by pathogen infection that are associated with inflammation and immune activation. While this paradigm has served the field well, numerous recent studies have highlighted cross talk between these programs, challenging the idea that apoptosis, pyroptosis, and necroptosis are linear pathways with defined immunological outputs. Here, we discuss the emerging idea of cell death as a signaling network, considering connections between cell death pathways both as we observe them now and in their evolutionary origins. We also discuss the engagement and subversion of cell death pathways by pathogens, as well as the key immunological outcomes of these processes.

Atherosclerosis, a chronic comprehensive cardiovascular disease, is characterized by the lipid infiltration, formation of foam cells derived from macrophages and inflammation in the vessel wall. Substantial evidence confirms that the activity of autophagic bodies plays a pivot role in regulating cell deaths, but the mechanisms of autophagy to regulate the pyroptosis of macrophages in atherosclerosis remain unclear. In our study, we explored that ox-LDL decreased the cell viability and destroyed the integrity of cell membrane, resulting in the pyroptosis of THP-1 derived macrophages in a dose-dependent manner. Western blotting, qRT-PCR and ELISA also showed that chloroquine (CQ) could up-regulate the expression of p62 through impairing autophagy and induce the pyroptosis of macrophages treated by ox-LDL, as evidenced by the decrease of cell viability and membrane integrity, and the increase of pro-caspase-1, GSDMD, and proinflammatory factors IL-1β and IL-18. Further researches demonstrated that Nrf2, a nuclear factor activated by p62, was linked to macrophage pyroptosis. Overactivating or suppressing Nrf2/ARE signaling would correspondingly aggravate or alleviate pyroptosis, in which the level of p62 was regulated by Nrf2 feedback. Then, bioinformatic analysis verified that there was a close interaction between p62, Nrf2/ARE signaling proteins and pyroptosis-related proteins. Taken together, our results show that blocking autophagy promotes the pyroptosis of ox-LDL-treated macrophages via the p62/Nrf2/ARE axis, providing a novel therapeutic target for atherosclerosis.

Clonal haematopoiesis, which is highly prevalent in older individuals, arises from somatic mutations that endow a proliferative advantage to haematopoietic cells. Clonal haematopoiesis increases the risk of myocardial infarction and stroke independently of traditional risk factors1. Among the common genetic variants that give rise to clonal haematopoiesis, the JAK2V617F (JAK2VF) mutation, which increases JAK–STAT signalling, occurs at a younger age and imparts the strongest risk of premature coronary heart disease1,2. Here we show increased proliferation of macrophages and prominent formation of necrotic cores in atherosclerotic lesions in mice that express Jak2VF selectively in macrophages, and in chimeric mice that model clonal haematopoiesis. Deletion of the essential inflammasome components caspase 1 and 11, or of the pyroptosis executioner gasdermin D, reversed these adverse changes. Jak2VF lesions showed increased expression of AIM2, oxidative DNA damage and DNA replication stress, and Aim2 deficiency reduced atherosclerosis. Single-cell RNA sequencing analysis of Jak2VF lesions revealed a landscape that was enriched for inflammatory myeloid cells, which were suppressed by deletion of Gsdmd. Inhibition of the inflammasome product interleukin-1β reduced macrophage proliferation and necrotic formation while increasing the thickness of fibrous caps, indicating that it stabilized plaques. Our findings suggest that increased proliferation and glycolytic metabolism in Jak2VF macrophages lead to DNA replication stress and activation of the AIM2 inflammasome, thereby aggravating atherosclerosis. Precise application of therapies that target interleukin-1β or specific inflammasomes according to clonal haematopoiesis status could substantially reduce cardiovascular risk. Accelerated atherosclerosis in a mouse model of clonal haematopoiesis is prevented by genetic interruption of AIM2 inflammasome activation or by inhibition of interleukin-1β.