Subsequent Pyroptosis Research Articles

Triclosan induces pyroptosis by activation of the caspase-9/3/gasdermin E axis

The high concentrations of TCS in personal care products, and the potential for even greater exposure in occupational settings, raise significant concerns about its cytotoxic effects. Numorous studies highlight the importance of understanding the molecular mechanisms of pyroptosis in toxicological research on environmental pollutants. However, it remains unclear whether TCS exposure could induce GSDME-mediated pyroptosis. In this study, we aimed to investigate the cytotoxic effects of 200 μM TCS on L02 cells and elucidate the molecular mechanisms involved in TCS-induced pyroptosis, a novel form of cell death. Our results demonstrate that TCS inhibits the proliferation of L02 cells in a dose-dependent manner and triggers caspase-dependent cell death, leading to mitochondrial dysfunction and subsequent pyroptosis through the activation of the caspase-9/3/GSDME axis. Furthermore, through transcriptional and metabolomic analyses, we identified alterations in the PI3K-Akt and MAPK cellular signaling pathways, as well as changes in carbon and nitrogen metabolism. Our data provide valuable insights into the biotoxicity of high TCS concentrations and establish a theoretical basis for future studies on its impact and risk.

Glycolytic reprogramming governs crystalline silica-induced pyroptosis and inflammation through promoting lactylation modification

Prolonged inhalation of environmental crystalline silica (CS) can cause silicosis, characterized by persistent pulmonary inflammation and irreversible fibrosis, but the mechanism has not been elucidated. To uncover the role and underlying mechanism of glycolytic reprogramming in CS-induced pulmonary inflammation, the mouse silicosis models and glycolysis inhibition models were established in vivo. And the CS-induced macrophage activation models were utilized to further explore the underlying mechanism in vitro. The results showed that CS induced lung inflammation accompanied by glycolytic reprogramming and pyroptosis. The application of glycolysis inhibitor (2-DG) suppressed CS-induced pyroptosis and alleviated lung inflammation. In vitro, 2-DG effectively impeded CS-induced macrophage pyroptosis and inflammatory response. Mechanistically, 2-DG suppressed pyroptosis by inhibiting NLRP3 inflammasome activation both in vivo and in vitro. Furtherly, metabolite lactate facilitated NLRP3-dependent pyroptosis synergistically with CS particles, while blocking the source of lactate largely alleviated NLRP3 inflammasome activation and subsequent pyroptosis triggered by CS. More profoundly, the increment of lactate induced by CS might drive NLRP3-dependent pyroptosis by increasing histone lactylation levels. In conclusion, our findings demonstrated inhibiting glycolytic reprogramming could alleviate CS-induced inflammatory response through suppressing NLRP3 -dependent pyroptosis. Increased glycolytic metabolite lactate and protein lactylation modifications might represent significant mechanisms during CS-induced NLRP3 activation and macrophage pyroptosis.

Nanohybrid-Based Redox Homeostasis Perturbators Escaped from Early Lysosomes toward Amplified Sensitization of Tumor Cells and Photothermally Maneuvered Pyroptosis Therapy.

Reactive oxygen species (ROS) hold great potential in tumor pyroptosis therapy, yet they are still limited by short species lifespan and limited diffusion distance. Inducing cells into a metastable state and then applying external energy can effectively trigger pyroptosis, but systemic sensitization still faces challenges, such as limited ROS content, rapid decay, and short treatment windows. Herein, a nanohybrid-based redox homeostasis-perturbator system was designed that synergistically induce early lysosomal escape, autophagy inhibition, and redox perturbation functions to effectively sensitize cells to address these challenges. Specifically, weakly alkaline layered double hydroxide nanosheets (LDH NSs) with pH-responsive degradation properties enabled early lysosomal escape within 4 h, releasing poly(L-dopa) nanoparticles for inducing catechol-quinone redox cycling in the cytoplasm. The intracellular ROS levels were systematically rebounded by 3-4 times in tumor cells and lasted for over 4 h. Subsequently induced lysosomal stress and Ca2+ signaling activation resulted in severe mitochondrial dysfunction, as well as a perilous metastable state. Thereby, sequential near-infrared light was applied to trigger amplified stress through a local photothermal conversion. This led to sufficiently high levels of cleaved caspase-1 and GSDMD activation (2.5-2.8-fold increment) and subsequent pyroptosis response. In addition, OH- released by LDH elevated pH to alleviate the limitation of glutathione depletion by quinones at acidic pH and inhibit protective autophagy. Largely secreted inflammatory factors (2.5-5.6-fold increment), efficient maturation of dendritic cells, and further immune stimulation were boosted for tumor inhibition as a consequence. This study offers a new paradigm and insights into the synergy of internal systematic cellular sensitization and sequential external energy treatment to achieve tumor suppression through pyroptosis.

Oxidative photocatalysis on membranes triggers non-canonical pyroptosis

Intracellular membranes composing organelles of eukaryotes include membrane proteins playing crucial roles in physiological functions. However, a comprehensive understanding of the cellular responses triggered by intracellular membrane-focused oxidative stress remains elusive. Herein, we report an amphiphilic photocatalyst localised in intracellular membranes to damage membrane proteins oxidatively, resulting in non-canonical pyroptosis. Our developed photocatalysis generates hydroxyl radicals and hydrogen peroxides via water oxidation, which is accelerated under hypoxia. Single-molecule magnetic tweezers reveal that photocatalysis-induced oxidation markedly destabilised membrane protein folding. In cell environment, label-free quantification reveals that oxidative damage occurs primarily in membrane proteins related to protein quality control, thereby aggravating mitochondrial and endoplasmic reticulum stress and inducing lytic cell death. Notably, the photocatalysis activates non-canonical inflammasome caspases, resulting in gasdermin D cleavage to its pore-forming fragment and subsequent pyroptosis. These findings suggest that the oxidation of intracellular membrane proteins triggers non-canonical pyroptosis.

The LRRK2-G2019S mutation attenuates repair of brain injury partially by reducing the release of osteopontin-containing monocytic exosome-like vesicles

BackgroundBrain injury has been suggested as a risk factor for neurodegenerative diseases. Accordingly, defects in the brain's intrinsic capacity to repair injury may result in the accumulation of damage and a progressive loss of brain function. The G2019S (GS) mutation in LRRK2 (leucine rich repeat kinase 2) is the most prevalent genetic alteration in Parkinson's disease (PD). Here, we sought to investigate how this LRRK2-GS mutation affects repair of the injured brain. MethodsBrain injury was induced by stereotaxic injection of ATP, a damage-associated molecular pattern (DAMP) component, into the striatum of wild-type (WT) and LRRK2-GS mice. Effects of the LRRK2-GS mutation on brain injury and the recovery from injury were examined by analyzing the molecular and cellular behavior of neurons, astrocytes, and monocytes. ResultsDamaged neurons express osteopontin (OPN), a factor associated with brain repair. Following ATP-induced damage, monocytes entered injured brains, phagocytosing damaged neurons and producing exosome-like vesicles (EVs) containing OPN through activation of the inflammasome and subsequent pyroptosis. Following EV production, neurons and astrocytes processes elongated towards injured cores. In LRRK2-GS mice, OPN expression and monocytic pyroptosis were decreased compared with that in WT mice, resulting in diminished release of OPN-containing EVs and attenuated elongation of neuron and astrocyte processes. In addition, exosomes prepared from injured LRRK2-GS brains induced neurite outgrowth less efficiently than those from injured WT brains. ConclusionsThe LRRK2-GS mutation delays repair of injured brains through reduced expression of OPN and diminished release of OPN-containing EVs from monocytes. These findings suggest that the LRRK2-GS mutation may promote the development of PD by delaying the repair of brain injury.

Mito-Tempo alleviates ox-LDL-provoked foam cell formation by regulating Nrf2/NLRP3 signaling.

Our previous studies have demonstrated that Mito-Tempol (also known as 4-hydroxy-Tempo), a mitochondrial reactive oxygen species scavenger, alleviates oxidized low-density lipoprotein (ox-LDL)-triggered foam cell formation. Given the effect of oxidative stress on activating the NOD-, LRR-, and pyrin domain-containing 3 (NLRP3) inflammasome, which promotes foam cell formation, we aimed to explore whether Mito-Tempo inhibits ox-LDL-triggered foam cell formation by regulating NLRP3 inflammasome. The results revealed that Mito-Tempo re-activated Nrf2 and alleviated macrophage foam cell formation induced by ox-LDL, whereas the effects were reversed by ML385 (a specific Nrf2 inhibitor). Mito-Tempo restored the expression and nuclear translocation of Nrf2 by decreasing ox-LDL-induced ubiquitination. Furthermore, Mito-Tempo suppressed ox-LDL-triggered NLRP3 inflammasome activation and subsequent pyroptosis, whereas the changes were blocked by ML385. Mito-Tempo decreased lipoprotein uptake by inhibiting CD36 expression and suppressed foam cell formation by regulating the NLRP3 inflammasome. Taken together, Mito-Tempo exhibits potent anti-atherosclerotic effects by regulating Nrf2/NLRP3 signaling.

SIRT1 alleviates Cd nephrotoxicity through NF-κB/p65 deacetylation–mediated pyroptosis in rat renal tubular epithelial cells

Cadmium (Cd) is a widely distributed environmental pollutant, primarily causing nephrotoxicity through renal proximal tubular cell impairment. Pyroptosis is an inflammation-related nucleotide-binding oligomerization segment-like receptor family 3 (NLRP3)-dependent pathway for programmed cell death. We previously reported that inappropriate inflammation caused by Cd is a major contributor to kidney injury. Therefore, research on Cd-induced inflammatory response and pyroptosis may clarify the mechanisms underlying Cd-induced nephrotoxicity. In this study, we observed that Cd-induced nephrotoxicity is associated with NLRP3 inflammasome activation, leading to an increase in proinflammatory cytokine expression and secretion, as well as pyroptosis-related gene upregulation, both in primary rat proximal tubular (rPT) cells and kidney tissue from Cd-treated rats. In vitro, these effects were significantly abrogated through siRNA-based Nlrp3 silencing; thus, Cd may trigger pyroptosis through an NLRP3 inflammasome–dependent pathway. Moreover, Cd exposure considerably elevated reactive oxygen species (ROS) content. N-acetyl-l-cysteine, an ROS scavenger, mitigated Cd-induced NLRP3 inflammasome activation and subsequent pyroptosis. Mechanistically, Cd hindered the expression and deacetylase activity of SIRT1, eventually leading to a decline in SIRT1–p65 interactions, followed by an elevation in acetylated p65 levels. The administration of resveratrol (a SIRT1 agonist) or overexpression of Sirt1 counteracted Cd-induced RELA/p65/NLRP3 pathway activation considerably, leading to pyroptosis. This is the first study to reveal significant contributions of SIRT1-triggered p65 deacetylation to pyroptosis and its protective effects against Cd-induced chronic kidney injury. Our results may aid in developing potential therapeutic strategies for preventing Cd-induced pyroptosis through SIRT1-mediated p65 deacetylation.

Aryl hydrocarbon receptor confers protection against macrophage pyroptosis and intestinal inflammation through regulating polyamine biosynthesis.

Rationale: The aryl hydrocarbon receptor (AhR) functions in the regulation of intestinal inflammation, but knowledge of the underlying mechanisms in innate immune cells is limited. Here, we investigated the role of AhR in modulating the functions of macrophages in inflammatory bowel disease pathogenesis. Methods: The cellular composition of intestinal lamina propria CD45+ leukocytes in a dextran sulfate sodium (DSS)-induced mouse colitis model was determined by single-cell RNA sequencing. Macrophage pyroptosis was quantified by analysis of lactate dehydrogenase release, propidium iodide staining, enzyme-linked immunosorbent assay, western blot, and flow cytometry. Differentially expressed genes were confirmed by RNA-seq, RT-qPCR, luciferase assay, chromatin immunoprecipitation, and immunofluorescence staining. Results: AhR deficiency mediated dynamic remodeling of the cellular composition of intestinal lamina propria (LP) CD45+ immune cells in a colitis model, with a significant increase in monocyte-macrophage lineage. Mice with AhR deficiency in myeloid cells developed more severe dextran sulfate sodium induced colitis, with concomitant increased macrophage pyroptosis. Dietary supplementation with an AhR pre-ligand, indole-3-carbinol, conferred protection against colitis while protection failed in mice lacking AhR in myeloid cells. Mechanistically, AhR signaling inhibited macrophage pyroptosis by promoting ornithine decarboxylase 1 (Odc1) transcription, to enhance polyamine biosynthesis. The increased polyamine, particularly spermine, inhibited NLRP3 inflammasome assembly and subsequent pyroptosis by suppressing K+ efflux. AHR expression was positively correlated with ODC1 in intestinal mucosal biopsies from patients with ulcerative colitis. Conclusions: These findings suggest a functional role for the AhR/ODC1/polyamine axis in maintaining intestinal homeostasis, providing potential targets for treatment of inflammatory bowel disease.

Inhibition of NLRP3 inflammasome-A potential mechanistic therapeutic for treatment of polycystic ovary syndrome?

This review article explores the relationship between the NOD-like receptor protein 3 (NLRP3) inflammasome and the risk of developing polycystic ovary syndrome (PCOS). The NLRP3 inflammasome, a fundamental element of the innate immune system, plays a crucial role in the production of proinflammatory mediators and pyroptosis, a type inflammatory cell death. We conducted a thorough search on scientific databases to gather relevant information on this topic, utilizing relevant keywords. The reviewed studies indicated a correlation between PCOS and a higher incidence of granulosa cell (GC) death and the presence of ovarian tissue fibrosis. NLRP3 inflammasome stimulation and subsequent pyroptosis in GCs play a significant role in the pathophysiology of PCOS. Active NLRP3 inflammasome is involved in the production of inflammatory mediators like interleukin-1β (IL-1β) and IL-18, contributing to the development of PCOS, particularly in overweight patients. Therefore, inhibiting NLRP3 activation and pyroptosis could potentially offer novel therapeutic strategies for PCOS. Some limited studies have explored the use of agents with antioxidant and anti-inflammatory properties, as well as gene therapy approaches, to target the NLRP3 and pyroptosis signaling pathways. This study overview the understanding of the relationship between NLRP3 inflammasome activation, pyroptosis, and PCOS. It highlights the potential of targeting the NLRP3 inflammasome as an approach for treating PCOS. Nonetheless, further research and clinical trials are imperative to validate these results and explore the effectiveness of NLRP3 inflammasome inhibition in the management of PCOS.

PM2.5 induces renal tubular injury by activating NLRP3-mediated pyroptosis

Fine particulate matter (PM2.5)-related health issues have received increasing attention as a worldwide public health problem, and PM2.5-related chronic kidney disease (CKD) has been emerging over the years. Limited research has focused on the mechanism of PM2.5-induced kidney disease. To investigate the impact of PM2.5 on the kidney and its potential mechanism, we generated a PM2.5-exposed C57BL/6 mouse model by using Shanghai Meteorological and Environment Animal Exposure System (Shanghai-METAS) for 12 weeks, urine, blood and kidney tissues were collected. The pathological changes and the function of the kidney were measured after PM2.5 exposure for 12 weeks. Along with glomerular damage, tubular damage was also severe in PM2.5-induced mice. The results of mRNA-seq indicate that pyroptosis is involved. Pyroptosis is defined as caspase-1-dependent programmed cell death in response to insults. The expression of the nucleotide-binding and oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3), Caspase-1, gasdermin D (GSDMD) and IL-1β was detected. NLRP3 inflammasome activation and subsequent pyroptosis were observed in PM2.5-exposed kidney tissues and PM2.5-exposed Bumpt cells too. At the meantime, the inhibitors of NLRP3 and caspase-1 were applied to the PM2.5 exposed Bumpt cells. It turned out to have a significant rescue effect of the inhibitors. This study revealed new insights into PM2.5-induced kidney injury and specific kidney pathological damage, as well as morphological changes, and defined the important role of pyroptosis in PM2.5-induced kidney dysfunction.

Toxoplasma gondii Induces Pyroptosis in Human Placental Trophoblast and Amniotic Cells by Inducing ROS Production and Activation of Cathepsin B and NLRP1/NLRP3/NLRC4/AIM2 Inflammasome

Toxoplasma gondii infection in pregnant women may cause fetal anomalies; however, the underlying mechanisms remain unclear. The current study investigated whether T. gondii induces pyroptosis in human placental cells and the underlying mechanisms. Human placental trophoblast (BeWo and HTR-8/SVneo) and amniotic (WISH) cells were infected with T. gondii, and then reactive oxygen species (ROS) production, cathepsin B (CatB) release, inflammasome activation, and pyroptosis induction were evaluated. The molecular mechanisms of these effects were investigated by treating the cells with ROS scavengers, a CatB inhibitor, or inflammasome-specific siRNA. T. gondii infection induced ROS generation and CatB release into the cytosol in placental cells but decreased mitochondrial membrane potential. T. gondii-infected human placental cells and villi exhibited NLRP1, NLRP3, NLRC4, and AIM2 inflammasome activation and subsequent pyroptosis induction, as evidenced by increased expression of ASC, cleaved caspase-1, and mature IL-1β and gasdermin D cleavage. In addition to inflammasome activation and pyroptosis induction, adverse pregnancy outcome was shown in a T. gondii-infected pregnant mouse model. Administration of ROS scavengers, CatB inhibitor, or inflammasome-specific siRNA into T. gondii-infected cells reversed these effects. Collectively, these findings show that T. gondii induces NLRP1/NLRP3/NLRC4/AIM2 inflammasome-dependent caspase-1-mediated pyroptosis via induction of ROS production and CatB activation in placental cells. This mechanism may play an important role in inducing cell injury in congenital toxoplasmosis.

Ginsenoside compound K alleviates osteoarthritis by inhibiting NLRP3‑mediated pyroptosis.

Ginsenoside compound K (GCK) has been previously reported to be a potent antiarthritic and bone-protective agent. Therefore, the present study aimed to explore the potential effects of GCK on osteoarthritis and its regulatory effects on the pyroptosis of chondrocytes. Primary mouse chondrocytes (PMCs) were used for in vitro analysis. ELISA assays revealed that compared with the untreated cells, TNF-α induced a significant increase in IL-6, MMP13, A disintegrin and metalloproteinase with thrombospondin motifs 5 and MMP3 expression but induced a significant decrease in aggrecan and collagen II expression. By contrast, GCK reversed the aforementioned alterations in a dose-dependent manner. Experimental osteoarthritis was subsequently induced in mice through transection of the medial meniscotibial ligament and medial collateral ligament in the right knee [destabilization of the medial meniscus (DMM) mice]. GCK was found to reduce cartilage degradation in vivo in DMM mice, which was assessed using the Osteoarthritis Research Society International (OARSI) score, collagen II and MMP13 expression. Cartilage degradation is associated with higher OARSI score, decreased collagen II and increased MMP13 expression. In PMCs, TNF-α treatment stimulated an increase in the expression of NLR family pyrin domain containing 3 (NLRP3), Gasdermin D-N terminal (GSDMD-NT), cleaved caspase-1 and mature IL-1β, markers that indicate the occurrence of pyroptosis. However, GCK treatment suppressed the increase of the aforementioned proteins in a dose-dependent manner. Immunohistochemistry staining of the knee joint tissue sections from the DMM mice confirmed that GCK attenuated the NLRP3 and GSDMD-NT expression that was induced by DMM surgery. In conclusion, the present study revealed that GCK can reduce cartilage degradation in an osteoarthritis model by inhibiting the NLRP3-inflammasome activation and subsequent pyroptosis.

Dibutyl phthalate causes heart damage by disrupting Ca2+ transfer from endoplasmic reticulum to mitochondria and triggering subsequent pyroptosis

Dibutyl phthalate (DBP) is a typical plasticizer and is widely used in industrial manufacturing. DBP has been reported to be cardiotoxic, manifested by oxidative stress and inflammatory damage. However, the potential mechanism of heart damage caused by DBP remains unclear. By in vivo and in vitro experiments, first, this study demonstrated that DBP induced endoplasmic reticulum (ER) stress, mitochondrial damage, and pyroptosis in cardiomyocytes; second, it was confirmed that the ER stress increased mitochondrial-associated ER membrane (MAM), which led to mitochondrial damage by abnormalizing Ca2+ transfer within MAMs; finally, it was confirmed that mitochondrial reactive oxygen species (mtROS) production was increased after mitochondrial damage, which activated NLRP3 inflammasome and pyroptosis in cardiomyocytes. In summary, ER stress is the initiation of DBP cardiotoxicity, which leads to mitochondrial damage by disrupting Ca2+ transfer from ER to mitochondria. Subsequently, released mtROS promotes the activation of NLRP3 inflammasome and pyroptosis, eventually leading to heart damage.

Neutrophil Extracellular Traps Induce Alveolar Macrophage Pyroptosis by Regulating NLRP3 Deubiquitination, Aggravating the Development of Septic Lung Injury.

Uncontrolled inflammation is a typical feature of sepsis-related lung injury. The key event in the progression of lung injury is Caspase-1-dependent alveolar macrophage (AM) pyroptosis. Similarly, neutrophils are stimulated to release neutrophil extracellular traps (NETs) to participate in the innate immune response. This study aims to illustrate the specific mechanisms by which NETs activate AM at the post-translational level and maintain lung inflammation. We established a septic lung injury model by caecal ligation and puncture. We found elevated NETs and interleukin-1b (IL-1β) levels in the lung tissues of septic mice. Western blot and immunofluorescence analyses was utilized to determine whether NETs promote AM pyroptosis and whether degrading NETs or targeting the NLRP3 inflammasome had protective effects on AM pyroptosis and lung injury. Flow cytometric and co-immunoprecipitation analysesverified intracellular reactive oxygen species (ROS) levels and the binding of NLRP3 and ubiquitin (UB) molecules, respectively. Increased NETs production and IL-1β release in septic mice were correlated with the degree of lung injury. NETs upregulated the level of NLRP3, followed by NLRP3 inflammasome assembly and caspase-1 activation, leading to AM pyroptosis executed by the activated fragment of full-length gasdermin D (FH-GSDMD). However, the opposite effect was observed in the context of NETs degradation. Furthermore, NETs markedly elicited an increase in ROS, which facilitated the activation of NLRP3 deubiquitination and the subsequent pyroptosis pathway in AM. Removal of ROS could promote the binding of NLRP3 and ubiquitin, inhibit NLRP3 binding to apoptosis-associated spotted proteins (ASC) and further alleviate the inflammatory changes in the lungs. In summary, these findings indicate that NETs prime ROS generation, which promotes NLRP3 inflammasome activation at the post-translational level to mediate AM pyroptosis and sustain lung injury in septic mice.

TMBIM4 Deficiency Facilitates NLRP3 Inflammasome Activation-Induced Pyroptosis of Trophoblasts: A Potential Pathogenesis of Preeclampsia

Impaired invasion of EVTs results in inadequate remodelling of arteries and poor placentation, leading to PE. TMBIM4 was found to promote the migration and invasion of human osteosarcoma U2-OS and breast cancer MCF7 cell lines. However, the effect of TMBIM4 on trophoblast biological behaviour and its relevance to PE pathophysiology remain unclear. In this study, we confirmed that TMBIM4 was highly expressed in cytotrophoblasts, syncytiotrophoblasts, and EVTs of the human placenta during early pregnancy. By comparing the expression levels of TMBIM4 in the placenta of women with normal-term pregnancy and PE, TMBIM4 was found to be significantly decreased in PE. Thereafter, we determined the expression of TMBIM4 in the LPS-treated first-trimester human trophoblast cell line HTR-8/SVneo (mimicking a PE-like cell model), and determined the effect of TMBIM4 on trophoblast function and its underlying mechanism. LPS treatment reduced the expression of TMBIM4 and induced NLRP3 inflammasome activity in HTR-8/SVneo cells. KO of TMBIM4 in the HTR-8/SVneo cell line impaired cell viability, migration, and invasion, which was more severe in the LPS/ATP-treated TMBIM4-KO cell line. Moreover, TMBIM4 deficiency enhanced NLRP3 inflammasome activity and promoted subsequent pyroptosis, with or without LPS/ATP treatment. The negative relationship between TMBIM4 expression and NLRP3 inflammatory activity was verified in PE placentas. Inhibiting the NLRP3 inflammasome with MCC950 in HTR-8/SVneo cells alleviated LPS/ATP-induced pyroptosis and damaged cell function in the TMBIM4-KO cell line. Overall, this study revealed a new PE-associated protein, TMBIM4, and its biological significance in trophoblast pyroptosis mediated by the NLRP3 inflammasome. TMBIM4 may serve as a potential target for the treatment of placental inflammation-associated PE.

TgMIF Promotes Hepatocyte Pyroptosis and Recruitment of Proinflammatory Macrophages During Severe Liver Injury in Acute Toxoplasmosis.

Liver injury is a common complication during infection of Toxoplasma gondii. However, the Toxoplasma effector proteins involved remain unknown. Herein, we identified that T. gondii macrophage migration inhibitory factor (TgMIF) is a critical pathogenic factor of liver injury in acute toxoplasmosis mouse model induced by a less virulent strain, which is widely prevalent in humans. We show that TgMIF is a novel activator of nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome in hepatocytes, resulting in subsequent pyroptosis. Furthermore, T. gondii promotes the TgMIF-dependent infiltration of Ly6Chi proinflammatory macrophages to release cytokines, leading to hepatocyte apoptosis. Although the intense inflammation induced by TgMIF inhibits the proliferation of intracellular parasites, it results in fatal liver damage. In contrast, parasites with TgMIF gene deletion significantly alleviate liver injury and prolong mice survival. The discovery of novel Toxoplasma virulence factor may expedite the development of human toxoplasmosis control strategies.

Targeting the TLR4/NF-κΒ Axis and NLRP1/3 Inflammasomes by Rosuvastatin: A Role in Impeding Ovariectomy-Induced Cognitive Decline Neuropathology in Rats.

Postmenopausal hormone-related cognitive decline has gained an immense interest to explore the underlying mechanisms and potential therapies. The current work aimed to study the possible beneficial effect of rosuvastatin (ROS) on the cognitive decline induced by ovariectomy in rats. Four groups were used as follows: control group, control + rosuvastatin, ovariectomy, and ovariectomy + rosuvastatin. After sham operation or ovariectomy, rats were given saline or oral dosages of ROS (2mg/kg) every day for 30days. The cognitive functions were assessed using the Morris water maze paradigm, Y-maze test, and new object recognition test. After rat killing, TLR4, caspase-8, and NLRP mRNA expression and protein levels of ASC, AIM2, caspase-1, NLRP1, and PKR were measured in hippocampus. This was complemented by the estimation of tissue content of NF-κΒ, IL-1β, and IL-18 and serum lipid profile quantification. Rosuvastatin showed a promising potential for halting the cognitive impairments induced by estrogen decline through interfering with the TLR4/NF-κΒ/NLRP1/3 axis and inflammasomes activation and the subsequent pyroptosis. This was complemented by the amendment in the deranged lipid profile. Rosuvastatin may exert a beneficial role in attenuating the inflammatory and apoptotic signaling mechanisms associated with postmenopausal cognitive decline. Further investigations are needed to unveil the relationship between deranged plasma lipids and cognitive function.

Dihydromyricetin alleviates Escherichia coli lipopolysaccharide-induced hepatic injury in chickens by inhibiting the NLRP3 inflammasome

Dihydromyricetin (DHM), a flavonoid in vine tea, has many pharmacological activities, including anti-inflammatory and antibacterial effects. Lipopolysaccharide is the key inducer of inflammation in avian pathogenic Escherichia coli (E. coli) infection; however, the effect of DHM on E. coli lipopolysaccharide-induced hepatic injury remains unknown. The present study aimed to explore the role of the NLRP3 inflammasome in hepatic injury and the possible protective mechanisms of DHM against hepatic injury in chickens. The results showed that when chickens were administered lipopolysaccharide, liver damage was observed, accompanied by increased levels of serum transaminases and direct bilirubin. Additionally, hepatic expression levels of NLRP3 and caspase-1 p20, the subunit of caspase-1 that is cleaved after NLRP3 activation, significantly increased in liver injury. We found that treatment with MCC950, a specific NLRP3 inhibitor, significantly decreased serum transaminase activities, direct bilirubin content, and hepatic NLRP3 and caspase-1 p20 expression levels. DHM significantly reduced serum transaminase activities and direct bilirubin content and ameliorated histopathological and ultrastructural changes in the liver. DHM decreased hepatic levels of H2O2 and malondialdehyde and increased the activities of superoxide dismutase and glutathione peroxidase. Furthermore, DHM significantly decreased the expression levels of NLRP3, pro-caspase-1 and caspase-1 p20. Moreover, DHM reduced serum lactate dehydrogenase, IL-1β and IL-18 levels and repressed hepatic IL-1β, IL-18 and gasdermin A expression. The results demonstrated that the NLRP3 inflammasome was involved in the mechanism of lipopolysaccharide-induced hepatic injury. Furthermore, DHM could inhibit NLRP3 inflammasome activation and subsequent pyroptosis, eventually ameliorating E. coli lipopolysaccharide-induced liver injury.

Exendin-4 and linagliptin attenuate neuroinflammation in a mouse model of Parkinson's disease.

Use of glucagon-like peptide-1 receptor agonist or dipeptidyl peptidase 4 inhibitor has been shown to lower the incidence of Parkinson's disease in patients with diabetes mellitus. Therefore, using these two treatments may help treat Parkinson's disease. To further investigate the mechanisms of action of these two compounds, we established a model of Parkinson's disease by treating mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and then subcutaneously injected them with the glucagon-like peptide-1 receptor agonist exendin-4 or the dipeptidyl peptidase 4 inhibitor linagliptin. We found that both exendin-4 and linagliptin reversed motor dysfunction, glial activation, and dopaminergic neuronal death in this model. In addition, both exendin-4 and linagliptin induced microglial polarization to the anti-inflammatory M2 phenotype and reduced pro-inflammatory cytokine secretion. Moreover, in vitro experiments showed that treatment with exendin-4 and linagliptin inhibited activation of the nucleotide-binding oligomerization domain- and leucine-rich-repeat- and pyrin-domain-containing 3/caspase-1/interleukin-1β pathway and subsequent pyroptosis by decreasing the production of reactive oxygen species. These findings suggest that exendin-4 and linagliptin exert neuroprotective effects by attenuating neuroinflammation through regulation of microglial polarization and the nucleotide-binding oligomerization domain- and leucine-rich-repeat- and pyrin-domain-containing 3/caspase-1/interleukin-1β pathway in a mouse model of Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Therefore, these two drugs may serve as novel anti-inflammatory treatments for Parkinson's disease.

Cardioprotective activity of ethyl acetate extract of Cinnamomi Ramulus against myocardial ischemia/reperfusion injury in rats via inhibiting NLRP3 inflammasome activation and pyroptosis

BackgroundNLRP3 inflammasome activation and pyroptosis play an important role in myocardial ischemia/reperfusion injury (MI/RI). Cinnamomi ramulus (CR), is an important folk medicinal plant in China, which derived from the dried twig of Cinnamomum cassia (L.) Presl, has function of “warming and tonifying heart yang”, and traditionally utilized to treat the cold, blood-cold amenorrhea, phlegm, edema, arthralgia, and palpitations as well as improve blood circulation. The aqueous extract of C. ramulus was reported to show significant therapeutic potential for treating MI/RI. Whereas, there are no previous investigations in China or abroad has reported the cardioprotective effects and underlying mechanism of the ethyl acetate extract of C. ramulus (CREAE) and its bioactive substance cinnamic acid (CA) in triggering NLRP3 inflammasome activation and subsequent pyroptosis. PurposeThe present study aimed to assess the cardioprotective function of CREAE and CA against the MI/RI in rats and involved the underlying mechanisms. MethodsThe MI/RI model was established in male SD rats by occlusion of the left anterior descending coronary artery for 30 min followed by reperfusion for 120 min, respectively. The rats were intragastrically administered with CREAE (74 and 37 mg/kg) and CA (45 mg/kg) for 7 successive days before vascular ligation. The cardioprotective effects of CREAE and CA against myocardial injury of rats were detected by HE staining, TTC staining, echocardiograms, and myocardial enzymes detections. Serum levels of inflammatory factors, such as IL-6, IL-1β, and TNF-α, were analyzed by ELISA kits to evaluate the effects of CREAE and CA. The protein and gene expression levels of NLRP3 and the pyroptosis-related factors in heart tissue were conducted by western blot and RT-qPCR. ResultsOur results showed that CREAE and CA decrease myocardial infarct size and improve cardiac function, mitigate myocardial damage, and repress inflammatory response in rats after I/R. Mechanistically, our results revealed that CREAE and CA can dramatically suppress the activation of NLRP3 inflammasome and subsequent cardiomyocyte pyroptosis in myocardial tissues that as evidenced by downregulating the protein and gene expressions of NLRP3, ASC, IL-1β, caspase-1, gasdermin D, and N-terminal GSDMD. ConclusionsOur data indicated that CREAE and CA may attenuate MI/RI through suppression of NLRP3 inflammasome and subsequent pyroptosis-related signaling pathways.