Cell Pyroptosis Research Articles

Prolonged exposure to NaAsO2 induces thyroid dysfunction and inflammatory injury in Sprague‒Dawley rats, involvement of NLRP3 inflammasome‒mediated pyroptosis.

Arsenic, a well-known hazardous toxicant, has been found in recent years to act as an environmental endocrine disruptor that accumulates in various endocrine organs, impeding the normal physiological functions of these organs and altering hormone secretion levels. Moreover, some research has demonstrated a correlation between arsenic exposure and thyroid functions, suggesting that arsenic has a toxicological effect on the thyroid gland. However, the specific type of thyroid gland damage caused by arsenic exposure and its potential molecular mechanism remain poorly understood. In this study, the toxic effects of sodium arsenite (NaAsO2) exposure at different doses (0, 2.5, 5.0 and 10.0mg/kg bw) and over different durations (12, 24 and 36 weeks) on thyroid tissue and thyroid hormone levels in Sprague‒Dawley (SD) rats were investigated, and the specific mechanisms underlying the effects were also explored. Our results showed that NaAsO2 exposure can cause accumulation of this element in the thyroid tissue of rats. More importantly, chronic exposure to NaAsO2 significantly upregulated the expression of NLRP3 inflammasome-related proteins in thyroid tissue, leading to pyroptosis of thyroid cells and subsequent development of thyroid dysfunction, inflammatory injury, epithelial-mesenchymal transition (EMT), and even fibrotic changes in the thyroid glands of SD rats. These findings increase our understanding of the toxic effects of arsenic exposure on the thyroid gland and its functions.

Type III interferons induce pyroptosis in gut epithelial cells and impair mucosal repair.

Tissue damage and repair are hallmarks of inflammation. Despite a wealth of information on the mechanisms that govern tissue damage, mechanistic insight into how inflammation affects repair is lacking. Here, we investigated how interferons influence tissue repair after damage to the intestinal mucosa. We found that type III, not type I or type II, interferons delay epithelial cell regeneration by inducing the upregulation of Z-DNA-binding protein 1 (ZBP1). Z-nucleic acids formed following intestinal damage are sensed by ZBP1, leading to caspase-8 activation and the cleavage of gasdermin C (GSDMC). Cleaved GSDMC drives epithelial cell death by pyroptosis and delays repair of the large or small intestine after colitis or irradiation, respectively. The type III interferon/ZBP1/caspase-8/GSDMC axis is also active in patients with inflammatory bowel disease (IBD). Our findings highlight the capacity of type III interferons to delay gut repair, which has implications for IBD patients or individuals exposed to radiation therapies.

Apigenin attenuates cisplatin-induced hair cell damage in the zebrafish lateral line

Cisplatin, a widely used chemotherapy drug, is notorious for causing ototoxicity, which leads to irreversible sensorineural hearing loss by damaging cochlear sensory hair cells (HCs), spiral ganglion neurons (SGNs), and the stria vascularis (SV). Mechanisms include DNA adduct formation, mitochondrial dysfunction, oxidative stress, and inflammation, ultimately triggering cell death pathways like apoptosis, necroptosis, pyroptosis, or ferroptosis. Apigenin, a natural flavonoid found in various foods and beverages, possesses antioxidant, anti-inflammatory, and anti-tumor properties. Despite these benefits, its potential to mitigate cisplatin-induced ototoxicity remains unexplored. To investigate, we administered varying concentrations of apigenin (1 μM, 20 μM, 100 μM, and 250 μM) alongside cisplatin (200 μM) to zebrafish larvae at 5 days post fertilization. Cisplatin significantly reduced lateral line HCs, impacting auditory function as shown in startle response tests. However, co-administration with apigenin preserved lateral line HCs and mitigated cisplatin-induced hearing loss. In larvae exposed to cisplatin, TUNEL assay confirmed significant HCs apoptosis, which apigenin effectively countered by suppressing reactive oxygen species accumulation in lateral line HCs. RNA-seq analysis highlighted apigenin's role in modulating apoptosis-related pathways, supporting its protective effects against cisplatin-induced ototoxicity. These findings underscore apigenin's potential as a crucial protective agent against cisplatin-induced ototoxicity, meriting further investigation for clinical applications.

MiR-103–3p attenuates liver injury with severe acute pancreatitis by inhibiting pyroptosis through miR-103–3p/NLRP1 axis

BackgroundSevere acute pancreatitis (SAP) is a common digestive system disorder in clinical practice, and it is often associated with liver damage in patients with severe acute pancreatitis. Several studies have indicated that pyroptosis plays a role in liver damage following severe acute pancreatitis (SAP). However, the precise mechanisms remain unclear. This study aims to elucidate the association and specific mechanisms between liver injury following SAP and pyroptosis, providing theoretical support for research on SAP-induced liver injury. MethodsA rat model of SAP with concomitant liver injury was successfully established. The expression levels of miR-103–3p across different liver tissue groups were quantified using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Bioinformatic analyses and dual-luciferase reporter assays confirmed that NLRP1 is a direct target of miR-103–3p. In vivo assessments of miR-103–3p levels were performed, and the extent of cell pyroptosis during liver injury post-SAP was evaluated through western blotting, qRT-PCR, scanning electron microscopy, histopathology, immunofluorescence, and immunohistochemistry. The role of miR-103–3p in regulating NLRP1-mediated pyroptosis and its impact on SAP-induced liver injury were validated. ResultsThis study reports that following SAP-induced liver injury, the expression of miR-103–3p in liver tissue was significantly decreased, and cell pyroptosis was involved in the process of liver injury. Experimental validation indicated that NLRP1 was a downstream target of miR-103–3p. Overexpression of miR-103–3p in vitro significantly alleviated the severity of liver injury following SAP, while simultaneously inhibiting cell pyroptosis. ConclusionThese findings indicate that pyroptosis may be linked to SAP-induced liver injury and that miR-103–3p mitigates hepatocyte pyroptosis by reducing liver injury through the suppression of NLRP1 expression.

Newcastle disease virus promotes pyroptosis in medulloblastoma cells by regulating interferon-gamma-mediated guanylate-binding protein 1 expression and activating caspase-4

Objective: The literature has reported that Newcastle disease virus (NDV) can have inhibitory effects on various tumors. This study aims to investigate the mechanism by which NDV induces pyroptosis in medulloblastoma (MB) cells. Material and Methods: We treated MB cell lines Daoy and D283 with NDV or recombinant interferon-gamma (IFN-g) proteins. Guanylate-binding proteins (GBPs) were measured using real-time quantitative polymerase chain reaction. Small interfering RNA-specific targeting GBP1 was transfected into MB cells. Apoptosis was assessed using Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nucleoside nick end labeling and flow cytometry assays. Pyroptosis-related proteins, including caspase-4, caspase-1, and gasdermin D (GSDMD), were detected using Western blotting. Results: Bioinformatics analysis revealed that GBP family genes and interferon-related genes might be responsive to NDV stimulation in MB cells. Treatment with NDV resulted in increased IFN-g levels and upregulated GBP expression, particularly GBP1. In addition, IFN-g treatment induced GBP1 expression and enhanced cell apoptosis. GBP1 knockdown attenuated the decreased cell proliferation and increased cell apoptosis induced by NDV in MB cells. GBP1 overexpression upregulated the expression of pyroptosis-related proteins, including caspase-4, caspase-1, and GSDMD, subsequently leading to inhibition of cell proliferation and an increase in cell apoptosis levels. The silencing of caspase-4 confirmed the regulatory role of GBP1 in MB cell pyroptosis. Conclusion: Our findings suggest that NDV elevates IFN-g and GBP1 expression in MB cells, potentially contributing to caspase-4-mediated pyroptosis activation.

TNF-ɑ induces mitochondrial dysfunction to drive NLRP3/Caspase-1/GSDMD-mediated pyroptosis in MCF-7 cells

Pyroptosis is a gasdermin-mediated pro-inflammatory form of programmed cell death (PCD). Tumor necrosis factor-ɑ (TNF-ɑ) is an inflammatory cytokine, and some studies have shown that TNF-ɑ can cause pyroptosis of cells and exert anti-tumor effects. However, whether TNF-ɑ exerts anti-tumor effects on breast cancer cells by inducing pyroptosis has not been reported. In this study, to explore the impact of TNF-ɑ on pyroptosis in breast cancer cells, we treated MCF-7 cells with TNF-ɑ and found that TNF-ɑ induced cell death. Moreover, we observed that the dead cells were swollen with obvious balloon-like bubbles, which was a typical sign of pyroptosis. Further studies have found that the anti-tumor effect of TNF-ɑ on breast cancer cells in vitro was achieved through the canonical pyroptosis pathway. In addition, TNF-ɑ-induced pyroptosis in MCF-7 cells was associated with mitochondrial dysfunction, in which mitochondrial membrane potential was decreased and mitochondrial ROS production was increased. After inhibiting ROS production, the activation effect of TNF-ɑ on NLRP3/Caspase-1/GSDMD pathway was weakened, and the inhibitory effect of TNF-ɑ on the growth of MCF-7 cells in vitro was also decreased, further confirming the involvement of ROS in TNF-ɑ-induced pyroptosis. Overall, our study revealed a new mechanism by which TNF-ɑ exerts an anti-tumor effect by inducing pyroptosis in MCF-7 cells through the ROS/NLRP3/Caspase-1/GSDMD pathway, which may provide new therapeutic ideas for the treatment of breast cancer.

Macrophage MST4 exacerbates cardiac microvascular ischaemia/reperfusion injury by phosphorylating ACLY

Abstract Background Cardiac microvascular dysfunction is a contributing factor in the development of cardiac ischaemia/reperfusion (I/R) injury. The STE20-type kinases play important role in cardiovascular diseases. However, the impact of mammalian Ste20-like kinase 4 (MST4) on cardiac microvascular I/R injury remains unknown. Purpose To decipher the role of MST4 in cardiac microvascular I/R injury and the underlying mechanisms. Methods Single-cell RNA sequencing of I/R mouse heart was performed to explore the expression changes of MST4 in different cell types. MST4 flox (MST4 f/Y) mice was crossed with myeloid-specific LysM-Cre mice to generate myeloid-specific MST4 knockout mice (MST4 CKO). Bone marrow transplantation was used to testify the role of myeloid-derived MST4 in cardiac microvascular I/R injury. Bone-marrow-derived macrophage (BMDM) and cardiac microvascular endothelial cell (CMEC) were used to dissect molecular mechanisms. Adeno-associated virus and adenovirus were constructed to overexpress ATP Citrate Lyase (ACLY) with mutation of serine 455 (S455A) in vivo and in vitro, respectively. Phosphoproteomics, coimmunoprecipitation coupled with liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis and metabolomics were performed to decipher the downstream of MST4. Results MST4 is dominantly upregulated in CCR2+ monocyte-derived macrophages. Myeloid-specific deficiency of MST4 improves cardiac performance in I/R mouse model. Wild type (WT) mice transplanted with BMDM from MST4 CKO mice also exhibited improved cardiac function after I/R, however, MST4 CKO mice transplanted with BMDM from WT mice showed deteriorated cardiac performance. Metabolomics showed that primary bile acid biosynthesis pathway was upregulated in BMDM overexpressing MST4. The level of 7α-hydroxyl3-oxo-4-cholestenoic acid (7-HOCA), an intermediate of bile acid, was dramatically increased in I/R mice or BMDM overexpressing MST4, which can be reversed by knocking down MST4. Phosphoproteomics and LC-MS/MS analysis discovered that ACLY was one of the most important substrates of MST4 in the process of I/R injury. ACLY was directly phosphorylated by MST4 at serine 455, which increased ACLY enzyme activity. Mechanistically, ACLY promoted cholesterol catabolism through the bile acid synthesis pathway, leading to the accumulation of 7-HOCA in the macrophage-endothelial cell microenvironment. High level of 7-HOCA was able to promote endothelial cell mtDNA release, leading to endothelial cell pyroptosis through inflammasome pathway. However, mutation of serine 455 of ACLY blocked the role of MST4. Conclusions Our data defined a previously unrecognized role of MST4/ACLY pathway in cardiac microvascular I/R injury. MST4 led to the accumulation of 7-HOCA by phosphorylating ACLY, furthermore, 7-HOCA promoted endothelial cell injury. Targeting MST4/ACLY pathway ameliorated microvascular I/R injury, which may provide a novel therapeutic strategy for I/R injury.

Engineering exosomes from fibroblast growth factor 1 pre-conditioned adipose-derived stem cells promote ischemic skin flaps survival by activating autophagy

BackgroundThe recovery of ischemic skin flaps is a major concern in clinical settings. The purpose of this study is to evaluate the effects of engineered exosomes derived from FGF1 pre-conditioned adipose-derived stem cells (FEXO) on ischemic skin flaps. Method6 patients who suffered from pressure ulcer at stage 4 and underwent skin flaps surgery were recruited in this study to screen the potential targets of ischemic skin flaps in FGF family. FGF1 was co-incubated with adipose stem cells, and ultracentrifugation was applied to extract FEXO. Transcriptome sequencing analysis was used to determine the most effective microRNA in FEXO. Animal skin flaps models were established in our study to verify the effects of FEXO. Immunofluorescence (IF), western blotting (WB) and other molecular strategy were used to evaluate the effects and mechanism of FEXO. ResultsFGF1 was expected to be the therapeutic and diagnostic target of ischemic skin flaps, but there is still some deficiency in rescuing skin flaps. FEXO significantly improved the viability of RPSFs and endothelial cells by inhibiting oxidative stress and alleviating apoptosis and pyroptosis through augmenting autophagy flux. In addition, FEXO inhibited the over-activated inflammation responses. Transcriptome sequencing analysis showed that miR-183-5p was significantly elevated in FEXO, and inhibiting miR-183-5p resulted in impaired protective effects of autophagy in skin flaps. The exosomal miR-183-5p markedly enhanced cell viability, inhibited oxidative stress and alleviated apoptosis and pyroptosis in endothelial cells by targeting GPR137 through Pi3k/Akt/mTOR pathway, indicating that GPR137 could also be a therapeutic target of ischemic skin flap. It was also notabale that FGF1 increased the number of exosomes by upregulating VAMP3, which may be a promising strategy for clinical translation. ConclusionFEXO markedly improved the survivial rate of ischemic skin flaps through miR-183-5p/GPR137/Pi3k/Akt/mTOR axis, which would be a promising strategy to rescue ischemic skin flaps.

METTL14 Promotes Ischemic Stroke-induced Brain Injury by Stabilizing HDAC3 Expression in an m6A-IGF2BP3 Mechanism.

N6-methyladenosine (m6A) modification is the most abundant post-transcriptional modification of mRNAs and has been identified to play critical roles in ischemic stroke (IS). Herein, this study aimed to investigate the function and mechanism of Methyltransferase-like 14 (METTL14) methylase in cerebral IS. Murine BV-2 microglial cell OGD/R models and rat middle cerebral artery occlusion (MCAO) models were established to mimic IS-induced neuronal damage in vitro and brain injury in vivo. Levels of METTL14, Histone Deacetylase 3 (HDAC3) and cGAS-STING axis-related proteins were detected using qRT-PCR or western blotting. Cell proliferation and inflammation were assessed by CCK-8 assay, EdU assay and ELISA. Flow cytometry detected microglia polarization. Cell pyroptosis was analyzed by detecting related-protein markers by western blotting. The m6A modification was determined by methylated RNA immunoprecipitation assay. Brain injury was analyzed by evaluating infarct volume and neurologic score. METTL14 levels were higher in OGD/R-induced microglial cells, primary microglia and infarct brain tissues of rat MCAO models. Functionally, METTL14 silencing reversed OGD/R-induced proliferation inhibition, inflammation and pyroptosis in microglial cells and primary microglia in vitro, and ameliorated cerebral ischemic injury in rat MCAO models. Mechanistically, METTL14 induced HDAC3 m6A modification in an IGF2BP3-dependent manner, and could activate cGAS-STING pathway through HDAC3. Moreover, HDAC3 overexpression reversed the neuroprotective effects of METTL14 silencing. METTL14 silencing reversed ischemic stroke-induced brain injury by inducing HDAC3 m6A modification in an IGF2BP3-dependent mechanism, recommending a novel insight for ameliorating cerebral ischemic stroke.

Role of Sphingosine-1-Phosphate Signaling Pathway in Pancreatic Diseases.

Sphingosine-1-phosphate (S1P) is a sphingolipid metabolic product produced via the phosphorylation of sphingosine by sphingosine kinases (SPHKs), serving as a powerful modulator of various cellular processes through its interaction with S1P receptors (S1PRs). Currently, this incompletely understood mechanism in pancreatic diseases including pancreatitis and pancreatic cancer, largely limits therapeutic options for these disorders. Recent evidence indicates that S1P significantly contributes to pancreatic diseases by modulating inflammation, promoting pyroptosis in pancreatic acinar cells, regulating the activation of pancreatic stellate cells, and affecting organelle functions in pancreatic cancer cells. Nevertheless, no review has encapsulated these advancements. Thus, this review compiles information about the involvement of S1P signaling in exocrine pancreatic disorders, including acute pancreatitis, chronic pancreatitis, and pancreatic cancer, as well as prospective treatment strategies to target S1P signaling for these conditions. The insights presented here possess the potential to offer valuable guidance for the implementation of therapies targeting S1P signaling in various pancreatic diseases.

A Virtual Insight into Bioactive Compounds of Ginger as Potential Inhibitors of NEK7 for Cancer Management

Background: NIMA-related kinase 7 (NEK7) is a serine/threonine kinase that is required for cell cycle progression, particularly mitotic spindle formation and cytokinesis, and has been linked to various cancers. Furthermore, NEK7 modulates the NLRP3 inflammasome, which activates Caspase-1 and causes cell pyroptosis. A growing body of studies indicates that ginger has the ability to prevent and treat a variety of health issues.Methods: In this study, 383 distinct bioactive compounds were extracted from the LOTUS database from Zingiber officinale and were screened against NEK7 protein using the PyRx 0.8 software. The top six hits' physicochemical characteristics, molecular descriptors, and natural product-likeness ratings were assessed using the LOTUS database.Results: The compounds LTS0101379, LTS0022317, TS0094590, LTS0231343, LTS0085481, and LTS0110340 showed high affinity for NEK7, forming interactions with critical amino acid residues. Notably, these compounds had multiple interactions with amino acid residues similar to those of the control compound Dabrafenib. Furthermore, the molecular properties and descriptors of these compounds indicated favorable drug-like properties.Conclusion: These findings highlight the potential of these compounds as NEK7 inhibitors for cancer management, though additional experimental validation is required.Keywords: NEK7; Cancer; Zingiber officinale; Virtual screening; Drug-likeness

Co-delivery of polyphyllin II and IR780 PLGA nanoparticles induced pyroptosis combined with photothermal to enhance hepatocellular carcinoma immunotherapy.

The clinical efficacy of immunotherapy for hepatocellular carcinoma (HCC) is significantly limited by the low immunogenicity of the tumor. Recent studies have revealed that both pyroptosis and photothermal therapy can effectively induce tumor immunogenic cell death (ICD) in liver cancer cells. Polyphyllin II (PPII), the major active component of Rhizoma Paridis, has been demonstrated for the first time to induce pyroptosis in tumor cells, while IR780 is activated by 808nm laser to transform light energy into heat energy, effectively eliminating tumor cells. However, both PPII and IR780 are afflicted with challenges such as low solubility and poor targeting, significantly limiting their utilization. To address these problems, the pyroptosis inducer PPII and photosensitizer IR780 were co-loaded in PLGA nanoparticles by precipitation method, and the aptamer AS1411 was modified on the surface of nanoparticles to construct the targeting nanoparticles (Apt/PPII/IR780-NPs). The nanoparticles exhibit a pH/NIR dual-response intelligent release feature, which realizes the targeted and controlled release of drugs in tumor site. Furthermore, it can rapidly release PPII to induce cell pyroptosis under laser irradiation, combining with IR780-based photothermal therapy exert a significant synergistic anti-tumor effect in vitro and in vivo. This process not only promotes maturation of DCs and activates effector T cells, thereby initiating adaptive immunity, but also generates enduring and effective immune memory. In addition, Apt/PPII/IR780-NPs significantly improved the Anti-PD-1 efficacy. In summary, chemo-photothermal therapy based on Apt/PPII/IR780-NPs can significantly enhance tumor ICD, which provides a promising new strategy for HCC immunotherapy.

Copper Overload Promotes β-amyloid Induced NLRP3/Caspase-1/GSDMD-Mediated Pyroptosis in Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by cognitive decline and abnormal protein accumulation. Copper imbalance and pyroptosis play significant roles in the pathogenesis of AD. Recent studies have suggested that dysregulated copper homeostasis contributed to β-amyloid accumulation, which may activate the NOD-like receptor protein 3 (NLRP3)-related pyroptosis pathway, promoting neuronal damages and AD progression. Therefore, the present study aims to investigates whether copper facilitates AD through exacerbating β-amyloid (Aβ) induced activation of NLRP3/Caspase-1/Gasdermin D (GSDMD)-mediated neuronal cell pyroptosis. Mouse hippocampal HT-22 cells were cultured with Aβ1-42 oligomer for 24 h as AD Model group. CuCl2 treatment was administered to the AD cell model, and cell survivability levels were detected by Cell Counting Kit-8 (CCK-8), TdT-mediated dUTP nick end labeling (TUNEL), and other relevant kits. Mitochondrial function was evaluated using Mitochondrial membrane potential dye JC-1 and transmission electron microscopy (TEM). After intervention with the NLRP3 inhibitor MCC950, activation of the NLRP3/Caspase-1/GSDMD pathway by copper ions (Cu2+) was confirmed via Western Blot. Thioredoxin T (ThT) fluorescence assay was performed to observe the aggregation effect of Aβ induced by Cu2+ overload. CuCl2 treatment of the AD cell model resulted in up-regulation of the levels of Lactate Dehydrogenase (LDH), Interleukin-1β (IL-1β), and IL-18 expression, which indicated activation of pyroptosis. We observed a significant decrease in mitochondrial membrane potential, mitochondrial swelling, and loss of mitochondrial cristae by fluorescence microscopy and TEM. ThT fluorescence imaging showed that Cu2+ promoted Aβ aggregation and up-regulated NLRP3, apoptosis-associated speck-like protein containing a CARD (ACS), Caspase-1, Cleaved Caspase-1, GSDMD, and Gasdermin D N-terminal (GSDMD-NT). The NLRP3 inhibitor MCC950 partially reversed Cu2+-mediated pyroptosis in HT-22 cells. Exposure to copper ions disrupt mitochondrial copper homeostasis, promotes Aβ aggregation, and activates NLRP3 inflammasomes, further promoting the Aβ aggregation activated pyroptosis in AD cell models.

METTL3-mediated m6A modification enhances lncRNA H19 stability to promote endothelial cell inflammation and pyroptosis to aggravate atherosclerosis.

This study explored the impact of N6-methyladenosine (m6A) modification on the regulation of long noncoding RNA (lncRNA) and atherosclerosis progression. An atherosclerosis cell model was established by treating human aortic endothelial cells (HAECs) with oxidized low-density lipoprotein. Additionally, an atherosclerotic animal model was developed using ApoE-/- C57BL/6 male mice fed a high-fat diet. Both models were employed to assess the expression changes of proteins associated with m6A modification. First, the effect of m6A modification writer protein methyltransferase-like 3 (METTL3) knockdown on changes in the level of pyroptosis in HAECs was investigated, and bioinformatic analysis confirmed that lncRNA H19 (H19) was the potential target of m6A modification. RNA-binding protein immunoprecipitation assays were subsequently performed to explore the interaction between H19 and the m6A writer protein METTL3, as well as the reader protein recombinant insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). Finally, the effect of H19 expression on pyroptosis levels in HAECs was evaluated. In the aortas of atherosclerosis mice, overall m6A levels were significantly elevated compared with controls (p < .05), with METTL3 and METTL14 mRNA and protein levels notably increased (p < .05). Similarly, ox-LDL-treated HAECs showed a significant rise in m6A levels, along with increased METTL3 and METTL14 expression (p < .05). METTL3 knockdown in HAECs led to decreased pyroptosis, as evidenced by reduced lactate dehydrogenase release and lower levels of IL-1β, IL-18, and IL-6 (p < .05). Overexpression of H19 reversed these effects, indicating METTL3's role in promoting atherosclerosis by stabilizing H19 through m6A modification. H19 was the primary target lncRNA molecule of METTL3-mediated m6A modification in the pathogenesis of atherosclerosis. METTL3-mediated m6A modification regulated H19 expression, thereby aggravating atherosclerosis by activating pyroptosis.

PRDM1 promotes nucleus pulposus cell pyroptosis leading to intervertebral disc degeneration via activating CASP1 transcription.

Intervertebral disc degeneration (IVDD) is a primary contributor to low back pain and poses a considerable burden to society. However, the molecular mechanisms underlying IVDD remain to be elucidated. PR/SET domain 1 (PRDM1) regulates cell proliferation, apoptosis, and inflammatory responses in various diseases. Despite these regulatory functions, the mechanism of action of PRDM1 in IVDD remains unexplored. In this study, we investigated the role and underlying mechanisms of action of PRDM1 in IVDD progression. The expression of PRDM1 in nucleus pulposus (NP) tissues and NP cells (NPCs) was assessed using western blotting, immunohistochemistry, and immunofluorescence. The effects of PRDM1 on IVDD progression were investigated in vitro and in vivo. Mechanistically, mRNA sequencing, chromatin immunoprecipitation, and dual-luciferase reporter assays were performed to confirm that PRDM1 triggered CASP1 transcription. Our study demonstrated for the first time that PRDM1 expression was substantially upregulated in degenerated NP tissues and NPCs. PRDM1 overexpression promoted NPCs pyroptosis by inhibiting mitophagy and exacerbating IVDD progression, whereas PRDM1 silencing exerted the opposite effect. Furthermore, PRDM1 activated CASP1 transcription, thereby promoting NPCs pyroptosis in vitro. Notably, CASP1 silencing reversed the effects of PRDM1 on the NPCs. To the best of our knowledge, this study is the first to demonstrate that PRDM1 silencing inhibits NPCs pyroptosis by repressing CASP1 transcription, which may be a promising new therapeutic target for IVDD.

Gasdermin D promotes development of intestinal tumors through regulating IL-1β release and gut microbiota composition

The interplay between gut microbiota and host is crucial for maintaining host health. When this balance is broken, various diseases can arise, including colorectal cancer (CRC). However, the mechanism by which gut microbiota and host interactions mediate CRC development remains unclear. Here, we found that Gasdermin D (GSDMD), an inflammasome effector responsible for forming membrane pores to mediate cell pyroptosis, was upregulated in both human and mouse intestinal tumor samples. GSDMD deficiency significantly suppressed intestinal tumor development in Apcmin/+ mice, a spontaneous CRC mouse model. Apcmin/+Gsdmd−/− mice exhibited reduced IL-1β release in the intestine, and the administration of recombinant mouse IL-1β partially restored intestinal tumor development in Apcmin/+Gsdmd−/− mice. Moreover, 16s rRNA sequencing showed a substantial increase in Lactobacillus abundance in the feces of Apcmin/+Gsdmd−/− mice compared to Apcmin/+ mice. Concurrently, Kynurenine (Kyn), a metabolite derived from host tryptophan (Trp) metabolism, was significantly decreased in the feces of Apcmin/+Gsdmd−/− mice, as shown by metabolite analysis. Additionally, Kyn levels were inversely correlated with Lactobacillus abundance. Furthermore, the administration of exogenous Kyn also promoted intestinal tumor development in Apcmin/+Gsdmd−/− mice. Thus, GSDMD promotes spontaneous CRC development through increasing IL-1β release and Kyn production. Our data suggest an association between GSDMD, gut microbiota, the host Trp/Kyn pathway, and CRC development.

Quercetin suppresses pyroptosis in mouse fibroblasts by inhibiting the NLRP3/caspase-1/GSDMD pathway

To investigate whether quercetin inhibits pyroptosis of mouse fibroblast NIH-3T3 cells by regulating the NLRP3/caspase-1/GSDMD signaling pathway. NIH-3T3 cells were treated with quercetin or MCC950 (a specific inhibitor of NLRP3) before stimulation with lipopolysaccharide (LPS) and ATP to induce cell pyroptosis. The optimal quercetin concentration and duration were screened using the CCK-8assay after testing various concentrations and times. Morphological changes of the treated cells was observed, and the levels of IL-18 and IL-1β in the cell culture supernatant were detected with ELISA; the protein expressions of NLRP3, cleaved caspase-1, and GSDMD-N and the mRNA levels of NLRP3, caspase-1 and GSDMD were detected using Western blotting and qRT-PCR. The changes in cell pyroptosis were examined with TUNEL staining and LDH release assay. The CCK-8 assay indicated that 24-hour treatment with 20 μmol/L quercetin yielded the most favorable results. LPS and ATP stimulation of NIH-3T3 cells induced obvious swelling, cell membrane rupture and leakage of cell contents, significantly increased IL-18 and IL-1β levels, and enhanced protein expressions of NLRP3, cleaved caspase-1 and GSDMD-N and mRNA levels of NLRP3, caspase-1 and GSDMD. LPS and ATP stimulation also caused a significant increment of TUNEL-positive cell counts and LDH release in NIH-3T3 cells. Treatment with quercetin or MCC950 significantly reduced cell pyroptosis induced by LPS and ATP, lowered the concentrations of IL-18 and IL-1β, decreased the expression levels of NLRP3, caspase-1/cleaved caspase-1, GSDMD/GSDMD-N, and reduced the number of TUNEL-positive cells and LDH release. Quercetin suppresses pyroptosis of mouse fibroblasts stimulated with LPS and ATP and reduces secretion of inflammatory cytokines by inhibiting the NLRP3/caspase-1/GSDMD pathway.

Ling-Gui-Zhu-Gan decoction inhibits cardiomyocyte pyroptosis via the NLRP3/Caspase-1 signaling pathway

ObjectiveThe objective of this study was to investigate the protective mechanism of Ling-Gui-Zhu-Gan decoction (LGZGD) against LPS-ATP-induced pyroptosis in H9c2 cells. MethodsLPS and ATP were used to induce pyroptosis in the H9c2 cell, and the cells were divided into the control, model and LGZGD groups. LDH level was detected using a colorimetric assay. ELISA was used to detect the expressions of IL-1β. Flow cytometry was utilized to observe apoptosis, while Hoechst/PI staining was used to detect pyroptosis. Immunofluorescence was employed to observe the expression levels of NLRP3 in cardiomyocytes, and RT-PCR was used to detect NLRP3, Caspase-1, GSDMD, and ASC mRNA expression. The cells were separated into seven groups: control, model, LGZGD, MCC950, LGZGD+MCC950, Nigericin and LGZGD+Nigericin. The mRNA and protein expressions were determined by RT-PCR and Western blot. ResultsLPS (10 μg/mL) for 12 h and ATP (8 mM) for 2 h were used as modeling condition. LGZGD demonstrated a significant reduction in LDH, and IL-1β levels (P<0.05, P<0.01). LGZGD dramatically reduced apoptosis rate, inhibited pyroptosis, decreased the fluorescence expressions of NLRP3, and reduced the mRNA expressions of NLRP3, ASC, Caspase-1, and GSDMD (P<0.01). Further mechanism studies showed that NLRP3, ASC, Caspase-1, and GSDMD decreased significantly when combined with NLRP3 inhibitor MCC950. Furthermore, LGZGD was able to effectively reverse the upregulation of protein and gene expression of Nigericin group (P<0.01). ConclusionLGZGD inhibits LPS-ATP-induced pyroptosis in H9c2 cell via the NLRP3/Caspase-1 signaling pathway.

USP33 promotes pulmonary microvascular endothelial cell pyroptosis by stabilizing TRAF2 through deubiquitination.

Inhibiting the pyroptosis of human pulmonary microvascular endothelial cells (HPMECs) is a promising therapeutic modality for acute lung injury (ALI). Given the undefined effect of ubiquitin-specific protease 33 (USP33) and tumor necrosis factor receptor-associated factor 2 (TRAF2) on pyroptosis in lung injury, this study investigates their roles in the pyroptosis of HPMECs during ALI. The hypoxia/reoxygenation (H/R)-induced model was constructed in HPMECs. Cell viability, cytotoxicity, and cell death were determined by the cell counting kit-8 (CCK-8), Lactate dehydrogenase (LDH), and Hoechst-PI staining, respectively. Western blot and qRT-PCR were used to detect protein and gene expression levels of pyroptosis-related markers, respectively. The TRAF2 ubiquitination level was measured via immunoprecipitation. USP33 and TRAF2 expressions were elevated in H/R-induced HPMECs. Knockdown of USP33 increased cell viability and inhibited cellular pyroptosis, accompanied by decreases in IL-1β, IL-18, and Caspase-1. USP33 stabilized TRAF2 by deubiquitination. TRAF2 overexpression reversed the effect of USP33 silencing on suppressing HPMEC pyroptosis. USP33 stabilizes TRAF2 by deubiquitination to promote HPMEC pyroptosis during ALI.

Eradication of Large Tumors by Nanoscale Drug Self-Assembly.

Most patients with cancer are first diagnosed at an advanced disease stage, when tumors are already large and/or metastases are present. This circumstance has a negative impact on the prognosis and therapeutic effect of anticancer drugs. In this study, it is demonstrated that photosensitizer chlorin e6 and the photochemotherapy drug mitoxantrone self-assemble into relatively stable nanoassemblies (CM NAs) through hydrogen-bonding effect, π-π stacking, and hydrophobic interactions. Administration of CM NAs in combination with 660nm laser irradiation shows chemotherapeutic, photothermal, and photodynamic effects, causing tumor cell apoptosis and pyroptosis and enabling noninvasive tumor ablation without compromising the surrounding normal tissue. More importantly, treatment with CM NAs increases tumor immunogenicity, leading to a strong and long-term antitumor immune response that eradicates large tumors and provides long-term protection against tumor recurrence on various tumor models.