Proinflammatory Programmed Cell Death Research Articles

Potential Impact of Climate Change-Induced Alterations on Pyroptotic Cell Death in Animal Cells: A Review.

Climate change-induced alterations in temperature variation, ozone exposure, water salinity and acidification, and hypoxia might influence immunity and thus survival in diverse groups ofanimals from fish to mammals. Pyroptosis is a type of lytic pro-inflammatory programmed cell death, which participates in the innate immune response, and is involved in multiple diseases characterized by inflammation and cell death, mostly studied in human cells. Diverse extrinsic factors can induce pyroptosis, leading to the extracellular release of pro-inflammatory moleculessuch as IL-18. Climate change-related factors, either directly or indirectly, can also promote animal cell death via different regulated mechanisms, impacting organismal fitness. However, pyroptosis has been relatively less studied in this context compared to another cell death process, apoptosis. This review covers previous research pointing to the potential impact of climate change, through various abiotic stressors, on pyroptotic cell death in different animal cells in various contexts. It was proposed that temperature, ozone exposure, watersalinity, wateracidification and hypoxia have the potential to induce pyroptotic cell death in animal cells and promote inflammation, and that these pyroptotic events should be better understood to be able to mitigate the adverse effects of climate change on animal physiology and health. This is of high importance considering the increasing frequency, intensity and duration of climate-based changes in these environmental parameters, and the critical function of pyroptosis in immune responses of animals and in their predisposition to multiple diseasesincluding cancer. Furthermore, the need for further mechanistic studies showing the more direct impact of climate change-induced environmental alterations on pyroptotic cell death in animals at the organismal level was highlighted. A complete picture of the association between climate change and pyroptosis in animals will be also highly valuable in terms of ecological and clinical applications, and it requires an interdisciplinary approach. SIGNIFICANCE: Climate change-induced alterations might influence animal physiology. Pyroptosis is a form of cell death with pro-inflammatory characteristics. Previous research suggests that temperature variation, ozone exposure, water salinity and acidification, and hypoxia might have the potential to contribute to pyroptotic cell death in certain cell types and contexts. Climate change-induced pyroptotic cell death should be better understood to be able to mitigate the adverse effects of climate change on animal health.

Abstract LB083: Near-infrared light-triggered tumor pyroptosis potentiates PD-1 immunotherapy in esophageal cancer

Abstract Background: Esophageal cancer remains a lethal malignancy accounting for 604,000 new cases and 544,000 cancer-related modalities worldwide. To date, the clinical outcomes for patient with esophageal cancer are severely limited by the lack of effective treatment modalities. Moreover, the intrinsic and acquired resistances to chemotherapy and radiotherapy, stemming from DNA damage responses, inevitably exacerbates the disease progression. Pyroptosis is a proinflammatory programmed cell death (PCD) that is causally linked to anti-tumor immune responses, but the development of pyroptosis-based therapy has been limited by the lack of effective inducers to mediate pyroptotic cell death in a tumor-specific and controllable manner. Herein, we establishes that near-infrared light-triggered tumor pyroptosis (NIR-pyroptosis) is a novel non-apoptotic anticancer modality, providing a promising opportunity to overcome apoptosis resistance in current esophageal cancer therapies. Method: In this study, a novel esophageal cancer-targeted, NIR-pyroptosis antibody-drug conjugates (ADC) was established by covalently conjugating IRDye700, a photosensitizer, with ICAM1 antibody using thiol-maleimide click chemistry. This antibody-photosensitizer conjugate (ICAM1-IRDye700) functions as a potent NIR-pyroptosis inducer in multiple preclinical models of esophageal squamous cell carcinoma (ESCC). The in vitro potency of ICAM1-IRDye700 was determined by flow cytometry, immunofluorescent co-localization, and high-content imaging. Transmission electron microscopy (TEM) further characterized pyroptosis-related morphological changes in ICAM1-IRDye700-treated ESCC cells. To elucidate its underlying mechanism, transcriptomic and immune-blot analyses were performed to identify the molecular signaling cascades of NIR-pyroptosis ignited by ICAM1-IRDye700. Results: Under minimal doses (2ug/ml) of near-infrared light stimulation, ICAM1-IRDye700 rapidly triggered pyroptosis in ESCC cells, achieving approximately 95% cell death within 2 hours. Importantly, the potency of NIR-pyroptosis predominantly depends on the spatio. At different stages of drug accumulation on the cell membrane, in endosomes, and lysosomes, the time of pyroptosis induction varied. Transmission electron microscopy further observed pyroptosis-related morphological changes, and immunoblot analysis and sequencing results also provided supporting evidence, demonstrating the activation of the subcellular depositing locations of ICAM1-IRDye700 upon NIR irradiation. Further biomechanistic studies reveal that ICAM1-IRDye700 potently activates NLRP1-CASP1-GSDMD signaling axis, leading to a boosted antitumor immunity in vivo. This antitumor immunity activation was independent from reactive oxygen species (ROS). Furthermore, NIR-pyroptosis works in synergy with PD-1 immunotherapy by improving adaptive antitumor immunity in immunocompetent tumor models. Conclusion: Collectively, we established ICAM1-IRDye700 as a concept-of-proof ADC for NIR-pyroptosis therapy. Mechanistically, we explored the biomechanism of how ICAM1-IRDye700 igniting NIR-pyroptosis in ESCC tumors. This novel ADC boosts innate and adaptive immunity, resulting in potent and sustained tumor attenuations in combination with PD-1 checkpoint immunotherapy. Citation Format: Xue-Fei Tian, Fan Chen, Xi-Ru Xue, Yang Yang, Peng Guo. Near-infrared light-triggered tumor pyroptosis potentiates PD-1 immunotherapy in esophageal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB083.

The dance of macrophage death: the interplay between the inevitable and the microenvironment.

Macrophages are highly plastic cells ubiquitous in various tissues, where they perform diverse functions. They participate in the response to pathogen invasion and inflammation resolution following the immune response, as well as the maintenance of homeostasis and proper tissue functions. Macrophages are generally considered long-lived cells with relatively strong resistance to numerous cytotoxic factors. On the other hand, their death seems to be one of the principal mechanisms by which macrophages perform their physiological functions or can contribute to the development of certain diseases. In this review, we scrutinize three distinct pro-inflammatory programmed cell death pathways - pyroptosis, necroptosis, and ferroptosis - occurring in macrophages under specific circumstances, and explain how these cells appear to undergo dynamic yet not always final changes before ultimately dying. We achieve that by examining the interconnectivity of these cell death types, which in macrophages seem to create a coordinated and flexible system responding to the microenvironment. Finally, we discuss the complexity and consequences of pyroptotic, necroptotic, and ferroptotic pathway induction in macrophages under two pathological conditions - atherosclerosis and cancer. We summarize damage-associated molecular patterns (DAMPs) along with other microenvironmental factors, macrophage polarization states, associated mechanisms as well as general outcomes, as such a comprehensive look at these correlations may point out the proper methodologies and potential therapeutic approaches.

Neuroinflammation Targeting Pyroptosis: Molecular Mechanisms and Therapeutic Perspectives in Stroke.

Pyroptosis is a recently identified type of pro-inflammatory programmed cell death (PCD) mediated by inflammasomes and nucleotide oligomerization domain-like receptors (NLs) and dependent on members of the caspase family. Pyroptosis has been widely reported to participate in the occurrence and progression of various inflammatory diseases, including stroke, a frequently lethal disease with high prevalence and many complications. To date, there have been no effectively therapeutic strategies and methods for treating stroke. Pyroptosis is thought to be closely related to the occurrence and development of stroke. Understanding inflammatory responses induced by the activation of pyroptosis would be hopeful to provide feasible approaches and strategies. Targeting on molecules in the upstream or downstream of pyroptosis pathway has shown promise in the treatment of stroke. The present review summarizes current research on the characteristics of pyroptosis, the function and pathological phenomena of pyroptosis in stroke, the molecule mechanisms related to inflammatory pathways, and the drugs and other molecules that can affect outcomes after stroke. These findings may help identify possible targets or new strategies for the diagnosis and treatment of stroke.

Unveiling the flames: macrophage pyroptosis and its crucial role in liver diseases.

Macrophages play a critical role in innate immunity, with approximately 90% of the total macrophage population in the human body residing in the liver. This population encompasses both resident and infiltrating macrophages. Recent studies highlight the pivotal role of liver macrophages in various aspects such as liver inflammation, regeneration, and immune regulation. A novel pro-inflammatory programmed cell death, pyroptosis, initially identified in macrophages, has garnered substantial attention since its discovery. Studies investigating pyroptosis and inflammation progression have particularly centered around macrophages. In liver diseases, pyroptosis plays an important role in driving the inflammatory response, facilitating the fibrotic process, and promoting tumor progression. Notably, the role of macrophage pyroptosis cannot be understated. This review primarily focuses on the role of macrophage pyroptosis in liver diseases. Additionally, it underscores the therapeutic potential inherent in targeting macrophage pyroptosis.

Preparation and characterization of monoclonal antibodies against porcine gasdermin D protein

Pyroptosis is a newly discovered type of pro-inflammatory programmed cell death that plays a vital role in various processes such as inflammations, immune responses, and pathogen infections. As one of the main executioners of pyroptosis, gasdermin D (GSDMD) is a membrane pore-forming protein that typically exists in a self-inhibitory state. Once activated, GSDMD will be cleaved into an N-terminal fragment with pore-forming activity, becoming the key indicator of pyroptosis activation, and a C-terminal fragment. Although commercial antibodies against human and murine GSDMD proteins are currently available, their reactivity with porcine GSDMD (pGSDMD) is poor, which limits research on the biological functions of pGSDMD and pyroptosis in pigs in vivo and in vitro. Here, five monoclonal antibodies (mAbs) were prepared by immunizing BALB/c mice with procaryotically expressed full-length pGSDMD, all of which did not cross react with human and murine GSDMD proteins. Epitope mapping demonstrated that 15H6 recognizes amino acids (aa) at positions 28–34 of pGSDMD (LQTSDRF), 19H3 recognizes 257–260aa (PPQF), 23H10 and 27A10 recognize 78–82aa (GPFYF), and 25E2 recognizes 429–435aa (PPTLLGS). The affinity constant and isotype of 15H6, 19H3, 23H10, 27A10, and 25E2 mAbs were determined to be 1.32 × 10−9, 3.66 × 10−9, 9.04 × 10−9, 1.83 × 10−9, and 8.00 × 10−8 mol/L and IgG1/κ, IgG2a/κ, IgG2a/κ, IgG1/κ, and IgG1/κ, respectively. Heavy- and light-chain variable regions sequencing showed that the heavy-chain complementarity-determining region (CDR) sequences of all five mAbs are completely different, while the light-chain CDR sequences of the four mAbs that recognize the N-terminus of pGSDMD are identical. Our prepared mAbs provide valuable materials for studying pGSDMD function and pyroptosis.Key points• A total of five mouse anti-pGSDMD mAbs were prepared, of which four recognize the N-terminus of pGSDMD and one recognize its C-terminus.• The main performance parameters of the five mAbs, including epitope, antibody titer, affinity constant, isotype, and heavy- and light-chain CDR, were characterized.• All five mAbs specifically recognize pGSDMD protein and do not cross react with human and murine GSDMD proteins.

Exogenous carbon monoxide promotes GPX4-dependent ferroptosis through ROS/GSK3β axis in non-small cell lung cancer

The gas therapy is drawing increasing attention in the treatment of many diseases including cancer. As one of gas signaling molecules, carbon monoxide (CO) has been proved to exert anti-cancer effects via triggering multiple cell death types, such as autophagy, apoptosis and necrosis. Here, we showed that low concentration CO delivered from CO-releasing molecule 3 (CORM-3) effectively induced ferroptosis, known as a novel proinflammatory programmed cell death, in vitro and in vivo. Mechanistically, we found that CO triggered ferroptosis by modulating the ROS/GSK3β/GPX4 signaling pathway, resulting in the accumulation of lipid hydroperoxides and the occurrence of ferroptosis. We think our findings provide novel insights into the anti-cancer mechanisms of CO, and suggest that CO could potentially be exploited as a novel ferroptosis inducer for cancer treatment in the future.

Diagnostic Model for Alzheimer's Disease Based on PANoptosis-Related Genes.

The pathophysiology of Alzheimer's disease (AD) involves the interplay of three different processes: pyroptosis, apoptosis, and necroptosis. To explore role of PANoptosis, a novel pro-inflammatory programmed cell death pathway, in AD patients. We performed a consensus clustering analysis to identify distinct transcriptional profiles in the samples using the R package "ConsensusClusterPlus". The PANoptosis key genes were obtained by crossing the WGCNA brown module and differentially expressed PANoptosis genes. We accomplished regression analyses using the LASSO-Cox method, combined with pathological status and gene expression data. At the same time, we also constructed PANscore system. The expression of PANoptosis hub genes were validated by qRT-PCR in AD transgenic mice. Our study utilized tissue expression profile data from AD patients to construct three distinct PANoptosis patterns, each with unique molecular and clinical characteristics. We have created a risk scoring system called PANscore, which can analyze patterns specific for each AD patient. Additionally, we observed significantly lower levels of follicular helper T (Tfh) cells in the high PANscore and AD patients. Further analysis revealed a significant negative correlation of Tfh with GSDMD and MLKL. These findings provide a roadmap for personalized patient stratification, enabling clinicians to develop personalized treatment plans for AD patients and advance the field of precision medicine.

Cathepsin B aggravates atherosclerosis in ApoE-deficient mice by modulating vascular smooth muscle cell pyroptosis through NF-κB / NLRP3 signaling pathway.

Atherosclerosis (AS) is a chronic inflammatory disease involving cell death and inflammatory responses. Pyroptosis, a newly discovered pro-inflammatory programmed cell death process, exacerbates inflammatory responses. However, the roles of cathepsin B (CTSB) in pyroptosis and AS remain unclear. To gain further insight, we fed ApoE-/- mice a high-fat diet to investigate the effects and mechanisms of CTSB overexpression and silencing on AS. We also explored the specific role of CTSB in vascular smooth muscle cells (VSMCs) in vitro. The study revealed that high-fat diet led to the formation of AS plaques, and CTSB was found to increase the AS plaque lesion area. Immunohistochemical and TUNEL/caspase-1 staining revealed the existence of pyroptosis in atherosclerotic plaques, particularly in VSMCs. In vitro studies, including Hoechst 33342/propidium iodide staining, a lactate dehydrogenase (LDH) release assay, detection of protein indicators of pyroptosis, and detection of interleukin-1β (IL-1β) in cell culture medium, demonstrated that oxidized low-density lipoprotein (ox-LDL) induced VSMC pyroptosis. Additionally, CTSB promoted VSMC pyroptosis. Ox-LDL increased the expression of CTSB, which in turn activated the NOD-like receptor protein 3 (NLRP3) inflammasome and promoted NLRP3 expression by facilitating nuclear factor kappa B (NF-κB) p65 nuclear translocation. This effect could be attenuated by the NF-κB inhibitor SN50. Our research found that CTSB not only promotes VSMC pyroptosis by activating the NLRP3 inflammasome, but also increases the expression of NLRP3.

Targeted inhibition of pyroptosis via a carbonized nanoinhibitor for alleviating drug-induced acute kidney injury.

Pyroptosis is a form of pro-inflammatory programmed cell death and it represents a potential therapeutic target for alleviating drug-induced acute kidney injury (AKI). However, there is a lack of effective and kidney-targeted pyroptosis inhibitors for AKI treatment so far. Herein, we report a pharmacologically active carbonized nanoinhibitor (P-RCDs) derived from 3,4',5-trihydroxystilbene that can preferentially accumulate in the kidneys and ameliorate chemotherapeutic drug-induced AKI by inhibiting pyroptosis. In particular, such a carbonized nanoformulation enables the transfer of desired pyroptosis inhibitory activity as well as the radical eliminating activity to the nanoscale, endowing P-RCDs with a favorable kidney-targeting ability. In cisplatin-induced AKI mice, P-RCDs can not only pharmacologically inhibit GSDME-mediated pyroptosis in renal cells with high efficacy, but also exhibit high antioxidative activity that protects the kidneys from oxidative injury. The present study proposes a feasible but efficacious strategy to construct versatile carbonized nanomedicine for targeted delivery of the desired pharmacological activities.

Application of pyroptosis score in the treatment and prognosis evaluation of gastric cancer.

Pyroptosis is a kind of proinflammatory programmed cell death mediated by inflammasome. It affects the occurrence and development of gastric cancer through different ways, showing dual effects. On the one hand, inflammasome-mediated inflammatory response is highly likely to participate in the formation and development of early tumors; on the other hand, drugs can inhibit the deterioration process of tumor proliferation, invasion and metastasis through activating the pathways of inflammasome and pyroptosis. Recently, many agents based on pyroptosis have been found to inhibit gastric cancer by promoting the secondary pyroptosis pathway, regulating NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and inhibiting caspase-1. The establishment of cell pyrodeath models can predict the prognosis of gastric cancer patients. Most of the models show that gastric cancer patients with high pyroptosis level have better prognosis and longer overall survival. Pyroptosis scores can also be used to predict the response of gastric cancer patients to immunotherapy and to screen potential anti-gastric cancer drugs. Therefore, in-depth understanding of the potential mechanism of pyroptosis affecting the progression of gastric cancer and the role of pyroptosis score in the treatment and prognosis assessment of gastric cancer will be helpful to find a new and effective method for the treatment of gastric cancer.

PANoptosis-related long non-coding RNA signature to predict the prognosis and immune landscapes of pancreatic adenocarcinoma

BackgroundCancer growth is significantly influenced by processes such as pyroptosis, apoptosis, and necroptosis that underlie PANoptosis, a proinflammatory programmed cell death. Several studies have examined the long non-coding RNAs (lncRNAs) associated with pancreatic adenocarcinoma (PAAD). However, the predictive value of lncRNAs related to PANoptosis for PAAD has not been established. MethodsThe Clinical Genome Atlas database was used to obtain the transcriptome 、clinical data and the corresponding mutation data of the patients with PAAD in this study. The least absolute shrinkage and selection operator regression analysis was employed to obtain prognosis-related lncRNAs for constructing a risk signature. According to the median risk score of the signature, patients with PAAD were grouped into low- and high-risk groups to further compare the survival prognosis of different risk groups. Time-dependent receiver operating characteristic curves, c-index analysis, nomograms, principal component analysis and univariate Cox and multivariate Cox regression were performed for the internal validation of the signature. In addition, enrichment analysis of different genes was performed using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Lastly, differences in tumor mutation burden (TMB), immune function, tumor immune dysfunction and rejection (TIDE), and drug response were determined for the two risk groups. ResultsThe signature was constructed with six PANoptosis-related lncRNAs (AC067817.2、LINC02004、AC243829.1、AC092171.5、AP005233.2、AC004687.1) that predicted the prognosis of the patients with PAAD. Survival curves showed that patients in the two risk groups had statistically significant differences in prognosis (P < 0.05), and multi-cox regression analysis identified risk score as an independent risk factor for PAAD prognosis, and internal validation of nomograms showed high confidence in the signature. GO and KEGG enrichment analysis showed functional and pathway differences between the high- and low-risk groups. TMB evaluation demonstrated that patients in the high-risk group had a higher frequency of mutations. The TIDE score indicated that the high-risk group had a lower risk of immunotherapy escape and better immunotherapy outcomes. Additionally, the two risk groups revealed significantly different responses to 11 anticancer drugs. ConclusionWe identified a novel risk signature for PANoptosis-related lncRNAs, which is a standalone prognostic indicator for PAAD. The PANoptosis-related lncRNA risk signature may be relevant for immunotherapy and a therapeutic target for PAAD.

Ibuprofen inhibits anaplastic thyroid cells in vivo and in vitro by triggering NLRP3-ASC-GSDMD-dependent pyroptosis

Pyroptosis is a novel type of proinflammatory programmed cell death that is associated with inflammation, immunity, and cancer. Anaplastic thyroid carcinoma (ATC) has a high fatality rate, and there is no effective or standard treatment. The disease progresses rapidly and these tumors can invade the trachea and esophagus, leading to breathing and swallowing difficulties. Hence, new treatment methods are greatly needed. Ibuprofen is a common drug that can exert antitumor effects in some cancers. In this study, we demonstrated in vitro and in vivo that ibuprofen can induce ATC pyroptosis. Hence, we treated C643 and OCUT-2C ATC cells with ibuprofen and found that several dying cells presented the characteristic morphological features of pyroptosis, such as bubble-like swelling and membrane rupture, accompanied by activation of ASC and NLRP3 and cleavage of GSDMD. Along with the increased release of LDH, ibuprofen treatment promoted apoptosis and inhibited viability, invasion, and migration. However, overexpression of GSDMD significantly inhibited ibuprofen-induced pyroptosis. In vivo, research has demonstrated that thyroid tumor growth in nude mice can be suppressed by ibuprofen-induced pyroptosis in a dose-dependent manner. In this research, we explored a new mechanism by which ibuprofen inhibits ATC growth and progression and highlighted its promise as a therapeutic agent for ATC.

Calcium sulfide based nanoreservoirs elicit dual pyroptosis pathways for enhanced anti-tumor immunity

The therapeutic efficacy of immunotherapy for most solid tumors is unsatisfactory due to the “immune-cold” nature. As a form of lytic pro-inflammatory programmed cell death, pyroptosis can release abundant immunogenic damage-associated molecular patterns to extracellular milieu, exhibiting self-cascade amplifying capacity for cancer immunotherapy. However, the activation of the caspase-3-mediated pyroptosis is difficult because mRNA hypermethylation induces the down-regulated GSDME expression. Herein, an integrated strategy to elicit dual pyroptosis pathways is introduced based on calcium sulfide-based nanoreservoirs (denoted as CSSG). CSSG are degraded in the aggravated acidic tumor microenvironment (TME) triggered by the surface GOx participating oxidation and result in the avalanching generation of H2S and Ca2+, which elevate oxidative pressure and induce mitochondrial respiration inhibition. Moreover, the sudden surge in H2S evokes GSDMD mediated pyroptosis through “DUSP6/ERK/NLRP3/caspase-1” signaling pathway, which synergistically reinforces the performance of the Ca2+ overloading initiating GSDME-mediated pyroptosis. CSSG elicit robust pyroptotic cell death to effectively stimulate tumor immunogenicity, and promote an impressive antitumor immunity with effective elimination of primary and distant tumors. Collectively, this work establishes TME-associated degradable nanomaterials to introduce dual pyroptosis pathways simultaneously and has a promising prospect in optimizing cancer immunotherapy.

Transcriptome analysis reveals the mechanism of pyroptosis-related genes in septic cardiomyopathy.

Septic cardiomyopathy (SC) is characterized by myocardial dysfunction caused by sepsis and constitutes one of the serious complications of sepsis. Pyroptosis is a unique proinflammatory programmed cell death process. However, the role of pyroptosis in the development of SC remains unclear, and further study is required. The purpose of this study is to identify pyroptosis-related genes (PRGs) in SC and explore the mechanism of pyroptosis involved in the regulation of SC formation and progression. Differential expression analysis and enrichment analysis were performed on the SC-related dataset GSE79962 to identify differentially expressed genes (DEGs). PRGs were screened by intersecting genes associated with pyroptosis in previous studies with the DEGs obtained from GSE79962. The expression pattern of them was studied based on their raw expression data. Additionally, corresponding online databases were used to predict miRNAs, transcription factors (TFs) and therapeutic agents of PRGs. Lipopolysaccharide (LPS)-induced cell damage models in H9C2 and AC16 cell lines were constructed, cell activity was detected by CCK-8 and cell pyroptosis were detected by Hoechst33342/PI staining. Furthermore, these PRGs were verified in the external datasets (GSE53007 and GSE142615) and LPS-induced cell damage model. Finally, the effect of siRNA-mediated PRGs knockdown on the pyroptosis phenotype was examined. A total of 1,206 DEGs were screened, consisting of 663 high-expressed genes and 543 low-expressed genes. Among them, ten PRGs (SOD2, GJA1, TIMP3, TAP1, TIMP1, NOD1, TP53, CPTP, CASP1 and SAT1) were identified, and they were mainly enriched in "Pyroptosis", "Ferroptosis", "Longevity regulating pathway", and "NOD-like receptor signaling pathway". A total of 147 miRNAs, 31 TFs and 13 therapeutic drugs were predicted targeting the PRGs. The expression trends of SOD2 were confirmed in both the external datasets and LPS-induced cell damage models. Knockdown of SOD2 induced increased pyroptosis in the AC16 LPS-induced cell damage model. In this study, we demonstrated that SOD2 is highly expressed in both the SC and LPS-induced cell damage models. Knockdown of SOD2 led to a significant increase in pyroptosis in the AC16 LPS-induced cell damage model. These findings suggest that SOD2 may serve as a potential target for the diagnosis and treatment of SC.

The Shigella flexneri virulence factor apyrase is released inside eukaryotic cells to hijack host cell fate.

Intestinal epithelial cells represent the first line of defense from invading enteric pathogens. During the course of infection, pro-inflammatory programmed cell death is an effective way to eliminate invading microbes and to create a localized inflammatory environment. On the other hand, pathogens evolved countless strategies to overcome cell death and to keep the host alive ensuring their spread. It was previously shown that Shigella flexneri apyrase interacts with OmpA to contribute to a proper polar exposition of IcsA, which mediates actin-based motility. However, apyrase is also an ATP-diphosphohydrolase whose catalytic activity function has not been elucidated yet. Herein, we demonstrated that apyrase contributes to the manipulation of host cell fate by S. flexneri since it is released within the host cell cytoplasm during infection to degrade intracellular ATP. Thus, apyrase contributes to prevent caspase-1 activation, thereby downregulating the activation of pyroptosis in infected cells. Overall, apyrase is involved in the modulation of host cell survival and dampens the inflammatory response.IMPORTANCEIn this paper, we demonstrated that apyrase is released within the host cell cytoplasm during infection to target the intracellular ATP pool. By degrading intracellular ATP, apyrase contributes to prevent caspases activation, thereby inhibiting the activation of pyroptosis in infected cells. Our results show, for the first time, that apyrase is involved in the modulation of host cell survival, thereby aiding this pathogen to dampen the inflammatory response. This work adds a further piece to the puzzle of Shigella pathogenesis. Due to its increased spread worldwide, prevention and controlling strategies are urgently needed. Overall, this study highlighted apyrase as a suitable target for an anti-virulence therapy to tackle this pathogen.

Role of NLRP3 inflammasome-mediated neuronal pyroptosis and neuroinflammation in neurodegenerative diseases.

Neurodegenerative diseases are a common group of neurological disorders characterized by progressive loss of neuronal structure and function leading to cognitive impairment. Recent studies have shown that neuronal pyroptosis mediated by the NLRP3 inflammasome plays a crucial role in the pathogenesis of neurodegenerative diseases. The NLRP3 inflammasome is a multiprotein complex that, when activated within cells, triggers an inflammatory response, ultimately leading to pyroptotic cell death of neurons. Pyroptosis is a typical pro-inflammatory programmed cell death process occurring downstream of NLRP3 inflammasome activation, characterized by the formation of pores on the cell membrane by the GSDMD protein, leading to cell lysis and the release of inflammatory factors. It has been found that NLRP3 inflammasome-mediated neuronal pyroptosis is closely associated with the development of various neurodegenerative diseases, such as Alzheimer's disease, traumatic brain injury, and Parkinson's disease. Therefore, inhibiting NLRP3 inflammasome activation and attenuating neuronal pyroptosis could potentially serve as novel strategies for the treatment of neurodegenerative diseases. The aim of this review is to explore the role of NLRP3 activation-mediated neuronal pyroptosis and neuroinflammation in neurodegenerative diseases. Firstly, we extensively discuss the relationship between NLRP3 inflammasome-mediated neuronal pyroptosis and neuroinflammation in various neurodegenerative diseases. Subsequently, we further explore the mechanisms driving NLRP3 activation and assembly, as well as the post-translational modifications regulating NLRP3 inflammasome activation. Understanding these mechanisms will contribute to a deeper understanding of the link between neuronal pyroptosis and neurodegenerative diseases, and hold significant implications for the treatment and prevention of neurodegenerative diseases.

Autophagy induced by PP121 alleviates MSU crystal-induced acute gouty arthritis via inhibition of the NLRP3 inflammasome

Acute gouty arthritis (AGA) is a frequent self-limiting inflammatory condition produced by the deposition of monosodium urate (MSU) crystals in the joints and periarticular tissues of patients with hyperuricemia. However, no effective interventional measures currently exist for AGA. Pyroptosis, a kind of pro-inflammatory programmed cell death, plays a crucial role in MSU crystal-induced inflammation and represents a potential treatment target for AGA. Therefore, we determined the therapeutic benefits and mechanism of PP121, a pyroptosis-related compound, on AGA. First, we injected an MSU crystal solution intra-articularly into the left foot pad of C57BL/6 mice to create an AGA mouse model. Subsequent treatment with PP121 substantially decreased tissue damage, pro-inflammatory cytokine release, and inflammatory cell infiltration caused by MSU crystals in the ankle joint. Consistent with these observations, the beneficial effects of PP121 on AGA were cancelled in Beclin1+/−(Becn1+/−) mice. Furthermore, after PP121 treatment, super-resolution microscopy revealed a strong relationship between lysosome-connected membrane protein/light chain 3 positive vesicles and the nucleotide-binding domain of leucine-rich family pyrin domain-containing 3 (NLPR3), demonstrating that PP121 promotes phagocytosis of the NLPR3 inflammasome. In summary, PP121-mediated autophagy can improve degradation of the NLRR3 inflammasome in AGA, which suggests the therapeutic potential of PP121 in AGA.

Cyclic helix B peptide alleviates proinflammatory cell death and improves functional recovery after traumatic spinal cord injury

BackgroundNecroptosis and pyroptosis, two types of proinflammatory programmed cell death, were recently found to play important roles in spinal cord injury (SCI). Moreover, cyclic helix B peptide (CHBP) was designed to maintain erythropoietin (EPO) activity and protect tissue against the adverse effects of EPO. However, the protective mechanism of CHBP following SCI is still unknown. This research explored the necroptosis- and pyroptosis-related mechanism underlying the neuroprotective effect of CHBP after SCI. MethodsGene Expression Omnibus (GEO) datasets and RNA sequencing were used to identify the molecular mechanisms of CHBP for SCI. A mouse model of contusion SCI was constructed, and HE staining, Nissl staining, Masson staining, footprint analysis and the Basso Mouse Scale (BMS) were applied for histological and behavioural analyses. qPCR, Western blot analysis, immunoprecipitation and immunofluorescence were utilized to analyse the levels of necroptosis, pyroptosis, autophagy and molecules associated with the AMPK signalling pathway. ResultsThe results revealed that CHBP significantly improved functional restoration, elevated autophagy, suppressed pyroptosis, and mitigated necroptosis after SCI. 3-Methyladenine (3-MA), an autophagy inhibitor, attenuated these beneficial effects of CHBP. Furthermore, CHBP-triggered elevation of autophagy was mediated by the dephosphorylation and nuclear translocation of TFEB, and this effect was due to stimulation of the AMPK-FOXO3a-SPK2-CARM1 and AMPK-mTOR signalling pathways. ConclusionCHBP acts as a powerful regulator of autophagy that improves functional recovery by alleviating proinflammatory cell death after SCI and thus might be a prospective therapeutic agent for clinical application.

Characteristic of molecular subtypes based on PANoptosis-related genes and experimental verification of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a type of liver cancer that originates from liver cells. It is one of the most common types of liver cancer and a leading cause of cancer-related death worldwide. Early detection and treatment can improve the HCC prognosis. Therefore, it is necessary to further improve HCC markers and risk stratification. PANoptosome is a cytoplasmic polymer protein complex that regulates a proinflammatory programmed cell death pathway called "PANoptosis". The role of PANoptosis in HCC remains unclear. In this study, the molecular changes of PANoptosis related genes (PAN-RGs) in HCC were systematically evaluated. We characterized the heterogeneity of HCC by using consensus clustering to identify two distinct subtypes. The two subtypes showed different survival rate, biological function, chemotherapy drug sensitivity and immune microenvironment. After identification of PAN-RG differential expression genes (DEGs), a prognostic model was established by Cox regression analysis using minimum absolute contraction and selection operator (LASSO), and its prognostic value was verified by Cox regression analysis, Kaplan-Meier curve and receiver operating characteristic (ROC) curve. Our own specimens were also used to further validate the prognostic significance and possible clinical value of the selected targets. Subsequently, we conducted a preliminary discussion on the reasons for the influence of the model on the prognosis through TME analysis, drug resistance analysis, TMB analysis and other studies. This study provides a new idea for individualized and precise treatment of HCC.