Proinflammatory Programmed Cell Death Research Articles

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.

Quercetin’in HepG2 hücrelerinde, TNF-Alfa ve LPS ile indüklenen enflamasyonda, eritropoietin, HIF-1α, HIF-2α ve piroptoz ile ilgili genlerin ekspresyon seviyeleri üzerine etkileri

Purpose: TNF-α, which increases in the circulation as a result of systemic inflammation, suppresses the production of the erythropoiesis regulating hormone, erythropoietin (EPO) and causes inflammation anemia. The anti-inflammatory activity of quercetin has been reported in different studies. However, no study has been found showing the effect of this situation on EPO gene expression. For this purpose, we evaluated the effects of quercetin on inflammation and, more importantly, its effects on EPO, suppressed in the inflammatory environment and Hypoxia-inducible factors (HIF), which are stimulators of EPO synthesis. In addition, we aimed to evaluate the effect of quercetin on pyroptosis, which is defined as pro-inflammatory programmed cell death.
 Materials and Methods: We created inflammation models with TNF-α or LPS using HepG2 cells in vitro. In these inflammation models, we evaluated the effects of quercetin on proinflammatory mediators TNF-α, IL-1α, NF-κB gene expressions, EPO, HIF-1α, HIF-2α gene expressions, as well as pyroptosis-related caspase 1 and IL-18 gene expressions. 
 Results: Quercetin showed inflammatory effects by increasing TNF-α, IL-1α, and NF-κB mRNA levels. Consistent with this inflammatory effect, EPO mRNA expression was suppressed. HIF-1α and HIF-2α mRNA levels were increased. 
 Conclusion: These results suggested that the increase in HIFs could not prevent the suppressive effect of inflammatory cytokines and NF-κB on EPO production. However, it has been observed that it tends to suppress proinflammatory cell death by decreasing caspase 1 and IL-18 mRNA levels. These results show that quercetin may show conflicting effects, and further studies are needed to test its safety.

Targeting Noncanonical Pyroptosis With a Small Molecular Inhibitor Alleviates Inflammation in the LPS-Induced Keratitis Mouse Model.

Pyroptosis, a novel proinflammatory programmed cell death, has been implicated in some ocular diseases. Of special note is the noncanonical pyroptosis that has recently been recognized to play a critical role in microbial keratitis. We previously discovered a new potent small molecular pyroptosis inhibitor, J114. In this investigation, we will explore whether J114 is able to inhibit the noncanonical pyroptosis and the underlying mechanism. Then a lipopolysaccharide (LPS)-induced keratitis mouse model will be used to evaluate the therapeutic effect of J114 in vivo. In vitro, macrophages originating from humans or mice were stimulated with intracellular LPS to induce noncanonical pyroptosis activation. in vivo, acute keratitis in mouse was induced by LPS intrastromal injection. We verified the protective effect of J114 on noncanonical pyroptosis. Clinical scoring, histological observation, macrophage localization, and quantification of pyroptotic markers in the cornea were used to characterize the therapeutic effects. J114 substantially inhibited the noncanonical pyroptosis and the release of inflammatory cytokines by suppressing the activation of caspase-4/5/11 and the noncanonical NLRP3 inflammasome through blocking the NLRP3-ASC interaction. in vivo, J114 protected against LPS-induced noncanonical pyroptosis of acute keratitis, as manifested by alleviated clinical manifestations and histological disorders, and relieved inflammatory reactions. In this study, we found that J114 could efficiently inhibit LPS-induced noncanonical pyroptosis and revealed the underlying mechanism. This compound displayed significant anti-inflammatory activity in the LPS-induced keratitis mouse model. All the findings indicated that J114 could be a potential lead compound for drug development against inflammatory ocular surface diseases.

A Identification of BAK1 as a novel prognostic biomarker for liver cancer based on the mining of liver cancer pyroptosis-related genes

Hepatocellular carcinoma is a type of digestive tract cancer that has a high incidence and a poor prognosis. Pyroptosis, a newly discovered and proven method of pro-inflammatory programmed cell death, is linked to tumor development, patient prognosis, and response to therapy. In this study, the prognostic genes of liver cancer were obtained; their expressions were extracted from The Cancer Genome Atlas database; differential analysis, survival analysis, and clinical correlation analysis were performed; and a nomogram was constructed to predict the survival rate. Based on the expression of BAK1 gene, all samples were then divided into two groups: High expression and low expression. Enrichment analysis, immunological analysis, and drug susceptibility analysis of differential genes were subsequently performed in that order. BAK1 expression was found to be significantly higher in liver hepatocellular carcinoma (LIHC). High BAK1 expression levels were found to be linked to cancer development and poor prognosis. To assess the diagnostic value of BAK1 in LIHC, a receiver operating characteristic curve was drawn. In addition, there were significant differences in drug sensitivity between high and low BAK1 expression in 90 drugs. The BAK1 gene may be a good potential LIHC diagnostic marker, an oncogene in the occurrence and progression of liver cancer, a new prognostic biomarker, and a potential therapeutic target for liver cancer.

Hyperactivation of TRPV4 causes the hippocampal pyroptosis pathway and results in cognitive impairment in LPS-treated mice

Pyroptosis, a newly discovered proinflammatory programmed cell death, is involved in the regulation of cognitive dysfunction, such as Alzheimer's disease. Exploring potential drug targets that prevent pyroptotic procedures might benefit the development of a cure for these diseases. In the present study, we explored whether the transient receptor potential vanilloid 4 (TRPV4) blocker HC067047 and knockdown of TRPV4 in the hippocampus could improve cognitive behavior through the inhibition of pyroptosis in a mouse model developed using systemic administration of lipopolysaccharide (LPS). We found that systemic administration of HC067047 or knockdown of hippocampal TRPV4 prevented the activation of canonical and noncanonical pyroptosis in the hippocampus of LPS-treated mice. Consistent with the inhibition of the hippocampal pyroptosis pathway, a knockdown of hippocampal TRPV4 lowered expression of TNF-α, IL-1β, IL-18, and IL-6. Furthermore, we verified that the main pyroptosis cell type might be a neuron, indicated by reduced neuronal marker expression. Mechanically, we also found that knockdown of hippocampal TRPV4 might inhibit phosphorylation of CamkⅡα which results in NFκb mediated inflammasome reduction in the hippocampus of LPS-treated mice. More interestingly, mice intraperitoneally injected with HC067047 or the hippocampus injected with TRPV4 shRNA showed improved cognitive behavior, as indicated by the enhanced discrimination ratio in the NORT, NOPT, and SNPT. Collectively, we consider that HC067047 might be a small molecular drug that prevents pyroptosis, and TRPV4 could be an effective therapeutic target for preventing pyroptosis-induced cognitive dysfunction.

Bibliometric analysis of global research trends on pyroptosis in lung disease.

BackgroundPyroptosis is a lytic pro-inflammatory programmed cell death mode that depends on caspase, inflammasome, and Gasdermin D (GSDMD). A growing number of studies have shown that pyroptosis is closely related to the pathophysiological mechanism of lung. The purpose of this study is to analyze the literature from Science Citation Index Expanded (SCI-expanded) of Web of Science Core Collection (WoSCC) and visualize the current trends and hotspots in the research of pyroptosis in lung disease.MethodsOn February 20, 2022, we retrieved all articles on pyroptosis in lung disease from SCI-expanded of WoSCC. Original articles and reviews published in English from 2007 to 2021 were included in the analysis. VOSviewer 1.6.17 and CiteSpace 5.8.R2 were used to analyze the retrieved data and visualize the results.Result1798 qualified original articles and reviews on pyroptosis in lung disease were included in the bibliometric analysis. So far, the research in this field is still in a period of growth, and the number of global publications has increased yearly. Among the 66 countries that have published relevant articles, China ranked first in the number of publications, and the USA ranked first in the number of cited articles. Holian,A. was the author with the largest number of articles, including 21 published. The University of California System in the USA was the organization with the largest number of articles, totaling 55. Frontiers in Immunology was the journal with the most publications in pyroptosis. After bibliometric analysis, the frequently used keywords are: “NOD-like receptor3 (NLRP3) inflammasome”, “inflammation”, “oxidative stress”, and “acute lung injury (ALI)”.ConclusionThe research on pyroptosis in lung disease is in its growth stage. The information released in this article may help researchers better understand the hotspots and developmental trends in this field, the cooperation network information of authors, countries, and institutions, and the citation correlation between articles. With the in-depth study of the mechanism of pyroptosis, the focus has shifted to increasing research on the connections and influences of different diseases. So far, increasing attention has been paid to the research field of the relationship between ALI and pyroptosis related to COVID-19.

Gasdermin D Deficiency Does Not Protect Mice from High-Fat Diet-Induced Glucose Intolerance and Adipose Tissue Inflammation.

The adipose tissue NLRP3 inflammasome has recently emerged as a contributor to obesity-related metabolic inflammation. Recent studies have demonstrated that the activation of the NLRP3 inflammasome cleaves gasdermin D (GSDMD) and induces pyroptosis, a proinflammatory programmed cell death. However, whether GSDMD is involved in the regulation of adipose tissue function and the development of obesity-induced metabolic disease remains unknown. The aim of the present study was to investigate the role of GSDMD in adipose tissue inflammation as well as whole-body metabolism using GSDMD-deficient mice fed a high-fat diet (HFD) for 30 weeks. The effects of GSDMD deficiency on adipose tissue, liver, and isolated macrophages from wild-type (WT) and GSDMD knockout (KO) mice were examined. In addition, 3T3-L1 cells were used to examine the expression of GSDMD during adipogenesis. The results demonstrate that although HFD-induced inflammation was partly ameliorated in isolated macrophages and liver, adipose tissue remained unaffected by GSDMD deficiency. Compared with the WT HFD mice, GSDMD KO HFD mice exhibited a mild increase in HFD-induced glucose intolerance with increased systemic and adipose tissue IL-1β levels. Interestingly, GSDMD deficiency caused accumulation of fat mass when challenged with HFD, partly by suppressing the expression of peroxisome proliferator-activated receptor gamma (PPARγ). The expression of GSDMD mRNA and protein was dramatically suppressed during adipocyte differentiation and was inversely correlated with PPARγ expression. Together, these findings indicate that GSDMD is not a prerequisite for HFD-induced adipose tissue inflammation and suggest a noncanonical function of GSDMD in regulation of fat mass through PPARγ.

Role of Pyroptosis, a Pro-inflammatory Programmed Cell Death, in Epilepsy.

Epilepsy is one of the most common serious brain diseases worldwide. Programmed cell death (PCD), a cellular self-destruction phenomenon, has been greatly documented in neurodegenerative diseases. Pyroptosis is a well-known pro-inflammatory PCD, and its involvement in epilepsy has been reported in animal models of epilepsy and also epileptic patients. Canonical (caspase-1-dependent) and non-canonical (caspase-1-independent) pathways are two main mechanisms implicated in pyroptotic cell death. Mouse caspase-11 or human analogues caspase-4/5 induce the non-canonical pathway. In both pathways, membrane gasdermin (GSDMD) pores contribute to pro-inflammatory cytokine release and lead to membrane destabilization and cell lysis. IL-1β and IL-18 are pro-inflammatory cytokines that are released following pyroptotic PCD. Brain inflammation increases excitabilityinthenervoussystem, promotes seizure activity, and is probably associated with the molecular and synaptic changes involved in epileptogenesis. Pro-inflammatory cytokines affect the glutamate and GABA neurotransmitter release as well as their receptors, thereby resulting in seizure activity. This review is intended to provide an overview of the current published works on pyroptotic cell death in epilepsy. The mechanisms by which pro-inflammatory cytokines, including IL-1β and IL-18 can promote epileptic discharges were also collected. According to this survey, since the involvement of pyroptosis in the development of epilepsy has been established, pyroptosis-targeted therapies may represent a novel anti-epileptogenic strategy.

Lighting a Fire: Gasdermin-Mediated Pyroptosis Remodels the Glioma Microenvironment and Promotes Immune Checkpoint Blockade Response.

Pyroptosis is a proinflammatory programmed cell death pathway mediated by gasdermins. Exploring the role of pyroptosis can provide new insights into tumor malignancy. The most recent studies on pyroptosis have focused on tumor cells. However, the effects of pyroptosis on the tumor microenvironment (TME), immunotherapeutic responses, and efficacy have been neglected, especially in case of glioma. In this study, four independent glioma cohorts comprising 1,339 samples and a pan-cancer cohort comprising 10,535 tumor samples were analyzed. The relationships among pyroptosis status, prognosis, microenvironment cellular components, and clinical and biological phenotypes were investigated through the identification of pyroptosis subtypes, construction of a gasdermin-related prognostic index (GPI), and evaluation of immunological characteristics in glioma. The Genomics of Drug Sensitivity in Cancer database and “pRRophetic” package in R were used to estimate temozolomide (TMZ) sensitivity. The “Submap” package and external immunotherapy cohorts were used to investigate and confirm the role of GPI in response to and efficacy of immunotherapy in glioma. Finally, potential small-molecule compounds related to GPI were identified using the connectivity map database and mode-of-action analysis. We identified three different pyroptosis subtypes: cluster 1 (C1) characterized by a higher GPI, while cluster 2 (C2) and cluster 3 (C3) characterized by a lower GPI. The high GPI of C1 was associated with glioma progression and worse prognoses, whereas the low GPI of subtype C2 and C3 was associated with better prognoses. However, patients with high GPIs were found to be more sensitive to TMZ and immune checkpoint blockade than those with low GPIs. Furthermore, gasdermin D may be a principal potential biomarker and play key roles in pyroptosis-inducible therapy combined with immunotherapy in glioma. This study provides a clinical, biological, and molecular landscape of pyroptosis and suggests that pyroptosis of glioma cells may perform the dual function of promoting both tumorigenesis and antitumor immunity.

MicroRNA-223–3p promotes pyroptosis of cardiomyocyte and release of inflammasome factors via downregulating the expression level of SPI1 (PU.1)

Diabetic cardiomyopathy (DCM) is a common heart disease in patients with diabetes mellitus (DM), and is sometimes its main cause of death. Among all the causes of DCM, myocardial cell death is considered to be the most basic pathological change. Furthermore, studies have shown that pyroptosis, the pro-inflammatory programmed cell death, contributes to the progress of DCM. MicroRNAs (miRNAs) also have been proved to take part in the formation of DCM. However, it is not clear whether and how miRNAs regulate myocardial cell pyroptosis in DCM development. In our study, the results showed that the expression of miR-223–3p was significantly increased in cardiomyocytes induced by high glucose, whereas the down-regulation of miR-223–3p weakened it. To understand the signal transduction mechanism of miR-223–3p leading to pyroptosis, we found inhibition of miR-223–3p expression down-regulated caspase-1, pro-inflammatory cytokines IL-1β and other pyroptosis-associated poteins. Moreover, miR-223–3p repressed SPI1 expression. Furthermore, we silenced SPI1 with siRNA to mimic the effect of miR-223–3p, up-regulating the expression of caspase-1 and resulting to pyroptosis. The above findings inspired us to propose a new signaling pathway to regulate scoria of cardiomyocytes under hyperglycemia: miR-223–3p↑→ SPI1↓→ caspase-1↑ → IL-1β and other pyroptosis-associated poteins↑→ pyroptosis↑. In summary, miR-223–3p could be a potential therapeutic target for DCM.

Gasdermin D mediates doxorubicin-induced cardiomyocyte pyroptosis and cardiotoxicity via directly binding to doxorubicin and changes in mitochondrial damage

Doxorubicin (Dox), as a widely used anthracycline antitumor drug, can cause severe cardiotoxicity. Cardiomyocyte death and inflammation are involved in the pathophysiology of Dox-induced cardiotoxicity (DIC). Gasdermin D (GSDMD) is known as a key executioner of pyroptosis, which is a pro-inflammatory programmed cell death. We aimed to investigate the impact of GSDMD on DIC and systematically reveal its underlying mechanisms. Our findings indicated that Dox induced cardiomyocyte pyroptosis in a GSDMD-dependent manner by utilizing siRNA or overexpression-plasmid technique. We then generated GSDMD global knockout mice via CRISPR/Cas9 system and found that GSDMD deficiency reduced Dox-induced cardiomyopathy. Dox induced the activation of inflammatory caspases, which subsequently mediated GSDMD-N generation indirectly. Using molecular dynamics simulation and cell-free systems, we confirmed that Dox directly bound to GSDMD and facilitated GSDMD-N-mediated pyroptosis. Furthermore, GSDMD also mediated Dox-induced mitochondrial damage via Bnip3 and mitochondrial perforation in cardiomyocytes. These findings provide fresh insights into the mechanism of how Dox-engaged GSDMD orchestrates adverse cardiotoxicity and highlight the prospects of GSDMD as a potential target for DIC.

Salidroside Ameliorates Depression by Suppressing NLRP3-Mediated Pyroptosis via P2X7/NF-κB/NLRP3 Signaling Pathway

Depression is a common and serious mental disorder. Data on its pathogenesis remain unclear and the options of drug treatments are limited. Here, we explored the role of pyroptosis, a novel pro-inflammatory programmed cell death process, in depression as well as the anti-depression effects and mechanisms of salidroside (Sal), a bioactive extract from Rhodiola rosea L. We established a corticosterone (CORT)-induced or lipopolysaccharide (LPS)-induced mice in vivo, and CORT, or nigericin (NLRP3 agonist)-induced PC12 cells in vitro. Our findings demonstrated that Sal profoundly mediated CORT or LPS-induced depressive behavior and improved synaptic plasticity by upregulating the expression of brain-derived neurotrophic factor (BDNF) gene. The data showed upregulation of proteins associated with NLRP3-mediated pyroptosis, including NLRP3, cleaved Caspase-1, IL-1β, IL-18, and cleaved GSDMD. The molecular docking simulation predicted that Sal would interact with P2X7 of the P2X7/NF-κB/NLRP3 signaling pathway. In addition, our findings showed that the NLRP3-mediated pyroptosis was regulated by P2X7/NF-κB/NLRP3 signaling pathway. Interestingly, Sal was shown to ameliorate depression via suppression of the P2X7/NF-κB/NLRP3 mediated pyroptosis, and rescued nigericin-induced pyroptosis in the PC12 cells. Besides, knock down of the NLRP3 gene by siRNA markedly increased the inhibitory effects of Sal on pyroptosis and proinflammatory responses. Taken together, our findings demonstrated that pyroptosis plays a crucial role in depression, and Sal ameliorates depression by suppressing the P2X7/NF-κB/NLRP3-mediated pyroptosis. Thus, our study provides new insights into the potential treatment options for depression.

Identification of a novel prognostic signature related to PANoptosis and its regulatory mechanism as well as targeted treatment of active ingredients and traditional Chinese medicine in lung adenocarcinoma

Lung adenocarcinoma (LUAD) with a poor prognosis is the most common type of lung cancer, and one of the most aggressive and rapidly fatal tumor types. PANoptosis is a newly identified pro-inflammatory programmed cell death pathway controlled by the recently discovered cytoplasmic polymeric protein complex is called a PANoptosome. PANoptosome Components are linked to a variety of human diseases, including autoinflammatory diseases, cancer, etc. However, the specific effect of PANoptosis regulatory factors in regulating the prognosis and potential mechanism in lung adenocarcinoma is unclear. Here, we ultimately identified 14 differentially expressed PANoptosis related regulators by comparing unpaired and paired lung adenocarcinoma samples and summarized the genetic mutations and molecular correlations of PANoptosis regulators in LUAD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these PANoptosis factors were mainly involved in the NOD-like receptor signaling pathway, necroptosis, TNF signaling pathway, apoptosis, and IL-17 signaling pathway. PANoptosis related prognostic signature based on three genes (FADD, MAP3K7, and NLRP3) has a good performance in prognostic prediction models of LUAD patients. The validation results showed that the expression trend of the FADD gene and protein was in agreement with the previous analysis results of the Cancer Genome Atlas (TCGA) database. In addition, we found that the expression of FADD was involved in most immune infiltrating cell types. We also found the regulatory axis of lncRNA TUG1/ miR-128–3p /FADD in the progression of LUAD. Besides, we found that resveratrol, quercetin, capsaicin, as well as Silybum marianum (L.) Gaertn. (Shui Fei Ji), Schisandra chinensis (Turcz.) Baill. (Wu Wei Zi), Mangifera indica L. (Mang Guo), Panax ginseng C.A.Mey. (Ren Shen) are potential therapeutic drugs targeting PANoptosis prognostic signature FADD. In a word, we analyzed and identified a novel PANoptosis related prognostic signature FADD as a potential biomarker for LUAD, and revealed its role in regulating immune microenvironment, as well as found its potential lncRNA TUG1/ miR-128–3p/FADD regulatory axis and targeted therapy traditional Chinese medicine (TCM) and active ingredients, which provides a basis for the development of new targeted immunotherapy drugs.

Discovery of a novel and potent inhibitor with differential species-specific effects against NLRP3 and AIM2 inflammasome-dependent pyroptosis

The NLRP3 inflammasome, which regulated a proinflammatory programmed cell death form termed pyroptosis, is involved in the pathological process of various human diseases, such as multiple sclerosis, type 2 diabetes, and gout. Thus, compounds inhibiting activation of the NLRP3 inflammasome can be promising treatments for these diseases. In this study, we conducted a phenotypic screening against NLRP3-dependent pyroptosis and discovered the hit compound 1, which showed moderate antipyroptotic activity. Chemistry efforts to improve potency of 1 resulted in a novel compound 59 (J114), which exhibited a half-maximal inhibitory concentration (IC50) of 0.077 ± 0.008 μM against cell pyroptosis. Interestingly, unlike all pyroptosis inhibitors currently reported, the activity of J114 showed significant differences in human- and mouse-derived cells. The IC50 of J114-mediated inhibition of IL-1β secretion by human THP-1 macrophages was 0.098 μM, which was nearly 150-fold and 500-fold more potent than that of J774A.1 (14.62 μM) and bone marrow-derived macrophages (BMDMs) (48.98 μM), respectively. Further studies showed that J114 displayed remarkable inhibitory activity against NLRP3- and AIM2-but not NLRC4-dependent activation of caspase-1 and the release of IL-1β in human THP-1 macrophages. Mechanistically, J114 disturbed the interaction of NLRP3 or AIM2 with the adaptor protein ASC and inhibited ASC oligomerization. Overall, our study identified a unique molecule that inhibits NLRP3 and AIM2 inflammasome activation and has species differences, which is worthy of further research to understand the differential regulation of the NLRP3 and AIM2 inflammasomes in humans and mice.

Pyroptosis: A possible link between obesity-related inflammation and inflammatory diseases.

The main manifestation of obesity is persistent low-level inflammation and insulin resistance, which is an important factor inducing or promoting other obesity-related diseases. As a proinflammatory programmed cell death, pyroptosis plays an important role, especially in the activation and regulation of the NLRP3 inflammasome pathway. Pyroptosis is associated with the pathogenesis of many chronic inflammatory diseases and is characterized by the formation of micropores in the plasma membrane and the release of a large number of proinflammatory cytokines. This article mainly introduces the main pathways and key molecules of pyroptosis and focuses on the phenomenon of pyroptosis in obesity. It is suggested that the regulation of pyroptosis-related targets may become a new potential therapy for the prevention and treatment of systemic inflammatory response caused by obesity, and we summarizethe potential molecular substances that may be beneficial to obesity-related inflammatory diseases through target pyroptosis.

Dihydroartemisinin mediating PKM2-caspase-8/3-GSDME axis for pyroptosis in esophageal squamous cell carcinoma

Pyroptosis is a novel type of pro-inflammatory programmed cell death that has been strongly reported to be related to inflammation, immune, and cancer. Dihydroartemisinin (DHA) has good anti-tumor properties. However, the exact mechanism by which DHA induces pyroptosis to inhibit esophageal squamous cell carcinoma (ESCC) remains unclear. After applying DHA treatment to ESCC, we found that some dying cells exhibited the characteristic morphology of pyroptosis, such as blowing large bubbles from the cell membrane, accompanied by downregulation of pyruvate kinase isoform M2 (PKM2), activation of caspase-8/3, and production of GSDME-NT. Meanwhile, it was accompanied by an increased release of LDH and inflammatory factors (IL-18 and IL-1β). Both knockdown of GSDME and application of caspase-8/3 specific inhibitors (z-ITED-FMK/Ac-DEVD-CHO) significantly inhibited DHA-induced pyroptosis. However, the former did not affect the activation of caspase-3. In contrast, overexpression of PKM2 inhibited caspase-8/3 activation as well as GSDME-N production. Furthermore, both si-GSDME and OE-PKM2 inhibited DHA-induced pyroptosis in vivo and in vitro. Therefore, the results suggest that DHA can induce pyroptosis of ESCC cells via the PKM2-caspase-8/3-GSDME pathway. Implication: In this study, we identified new mechanism of DHA in inhibiting ESCC development and progression, and provide a potential therapeutic agent for the treatment of ESCC.

Advances in research on cardiomyocyte pyroptosis mediated by NLRP3 inflammasome and traditional Chinese medicine intervention

Pyroptosis is a pro-inflammatory programmed cell death, and its role in cardiac inflammatory response has become a hot topic. The activation of nucleotide binding oligomerization domain like receptor protein 3(NLRP3) inflammasome is an important mechanism for pyroptosis induced by cysteinyl aspartate specific proteinase 1(caspase-1). The existing studies have shown that cardiomyocyte pyroptosis participates in the pathogenesis of different cardiovascular diseases and the NLRP3 inflammasome-mediated cardiomyocyte pyroptosis has been most widely studied. Also, the intervention in NLRP3 inflammasome activation and cardiomyocyte pyroptosis contributes to ameliorating myocardial injury, which may be the main mechanism of many traditional Chinese medicines in exerting the cardio-protective effects. Therefore, this paper reviewed the studies on cardiomyocyte pyroptosis mediated by NLRP3 inflammasome and put forward the importance of exploring traditional Chinese medicine intervention in the activation of NLRP3 inflammasome.

Trimetazidine attenuates dexamethasone-induced muscle atrophy via inhibiting NLRP3/GSDMD pathway-mediated pyroptosis

Skeletal muscle atrophy is one of the major side effects of high dose or sustained usage of glucocorticoids. Pyroptosis is a novel form of pro-inflammatory programmed cell death that may contribute to skeletal muscle injury. Trimetazidine, a well-known anti-anginal agent, can improve skeletal muscle performance both in humans and mice. We here showed that dexamethasone-induced atrophy, as evidenced by the increase of muscle atrophy F-box (Atrogin-1) and muscle ring finger 1 (MuRF1) expression, and the decrease of myotube diameter in C2C12 myotubes. Dexamethasone also induced pyroptosis, indicated by upregulated pyroptosis-related protein NLR family pyrin domain containing 3 (NLRP3), Caspase-1, and gasdermin-D (GSDMD). Knockdown of NLRP3 or GSDMD attenuated dexamethasone-induced myotube pyroptosis and atrophy. Trimetazidine treatment ameliorated dexamethasone-induced muscle pyroptosis and atrophy both in vivo and in vitro. Activation of NLRP3 using LPS and ATP not only increased the cleavage and activation of Caspase-1 and GSDMD, but also increased the expression levels of atrophy markers MuRF1 and Atrogin-1 in trimetazidine-treated C2C12 myotubes. Mechanically, dexamethasone inhibited the phosphorylation of PI3K/AKT/FoxO3a, which could be attenuated by trimetazidine. Conversely, co-treatment with a PI3K/AKT inhibitor, picropodophyllin, remarkably increased the expression of NLRP3 and reversed the protective effects of trimetazidine against dexamethasone-induced C2C12 myotube pyroptosis and atrophy. Taken together, our study suggests that NLRP3/GSDMD-mediated pyroptosis might be a novel mechanism for dexamethasone-induced skeletal muscle atrophy. Trimetazidine might be developed as a potential therapeutic agent for the treatment of dexamethasone-induced muscle atrophy.

Knockdown of long noncoding RNA growth arrest-specific transcript 5 regulates forkhead box O3 to inhibit lipopolysaccharide-induced human bronchial epithelial cell pyroptosis.

Pyroptosis is a novel proinflammatory programmed cell death process. This study was designed to investigate the functional mechanisms of long noncoding RNA growth arrest-specific transcript 5 (lncRNA GAS5) on lipopolysaccharide (LPS)-induced human bronchial epithelial cell (HBEC) pyroptosis. LPS was used to induce pyroptosis in HBECs, followed by the detection of the expression of GAS5, forkhead box O3 (FOXO3), and nuclear factor E2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) signaling pathway-related factors. Cell viability was evaluated using CCK-8 assay, lactate dehydrogenase (LDH) release was assessed by LDH assay kit and caspase-1 activity by flow cytometry. Furthermore, expression of NOD-like receptor family pyrin domain containing 3 and pyroptosis-related proteins was evaluated using Western blot analysis, while enzyme-linked immunosorbent assay was used to determine the levels of inflammatory factors. The interaction between GAS5 and FOXO3 was confirmed using bioinformatic prediction, RNA immunoprecipitation assay, RNA pull-down, and dual-luciferase reporter gene assay. Treatment of HBECs with LPS upregulated the expression of GAS5 and FOXO3, resulting in the inactivation of the Nrf2/HO-1 signaling pathway. On the other hand, inhibition of both GAS5 and FOXO3 promoted cell viability, reduced LDH release, pyroptosis, and inflammatory response in LPS-induced HBECs. Furthermore, FOXO3 could interact with GAS5, while FOXO3 overexpression reversed the inhibitory effect of GAS5 knockdown on cell pyroptosis. Thus, mechanistically, inhibition of FOXO3 activates the Nrf2/HO-1 pathway to suppress LPS-induced pyroptosis in HBECs. This study revealed that GAS5 knockdown attenuates FOXO3 expression thereby activating the Nrf2/HO-1 pathway to inhibit LPS-induced pyroptosis in HBECs. These findings may contribute to identifying novel targets that inhibit pyroptosis in HBECs.