Project description:Activating macrophage NLRP3 inflammasome can promote excessive inflammation, with severe cell and tissue damage and organ dysfunction. Here, we show that pharmacological or genetic inhibition of pyruvate dehydrogenase kinase (PDHK) significantly attenuates NLRP3 inflammasome activation in murine and human macrophages and septic mice by lowering caspase-1 cleavage and IL-1beta secretion. Inhibiting PDHK reverses NLRP3 inflammasome-induced metabolic reprogramming, enhances autophagy, promotes mitochondrial fusion over fission, preserves cristae ultrastructure, and attenuates mitochondrial ROS production. The suppressive effect of PDHK inhibition on the NLRP3 inflammasome is independent of its canonical role as a pyruvate dehydrogenase regulator. We suggest that PDHK inhibition improves mitochondrial fitness by reversing NLRP3 inflammasome activation in acutely inflamed macrophages.
Project description:Activating macrophage NLRP3 inflammasome can promote excessive inflammation, with severe cell and tissue damage and organ dysfunction. Here, we show that pharmacological or genetic inhibition of pyruvate dehydrogenase kinase (PDHK) significantly attenuates NLRP3 inflammasome activation in murine and human macrophages and septic mice by lowering caspase-1 cleavage and IL-1beta secretion. Inhibiting PDHK reverses NLRP3 inflammasome-induced metabolic reprogramming, enhances autophagy, promotes mitochondrial fusion over fission, preserves cristae ultrastructure, and attenuates mitochondrial ROS production. The suppressive effect of PDHK inhibition on the NLRP3 inflammasome is independent of its canonical role as a pyruvate dehydrogenase regulator. We suggest that PDHK inhibition improves mitochondrial fitness by reversing NLRP3 inflammasome activation in acutely inflamed macrophages.
Project description:Activating macrophage NLRP3 inflammasome can promote excessive inflammation, with severe cell and tissue damage and organ dysfunction. Here, we show that pharmacological or genetic inhibition of pyruvate dehydrogenase kinase (PDHK) significantly attenuates NLRP3 inflammasome activation in murine and human macrophages and septic mice by lowering caspase-1 cleavage and IL-1beta secretion. Inhibiting PDHK reverses NLRP3 inflammasome-induced metabolic reprogramming, enhances autophagy, promotes mitochondrial fusion over fission, preserves cristae ultrastructure, and attenuates mitochondrial ROS production. The suppressive effect of PDHK inhibition on the NLRP3 inflammasome is independent of its canonical role as a pyruvate dehydrogenase regulator. We suggest that PDHK inhibition improves mitochondrial fitness by reversing NLRP3 inflammasome activation in acutely inflamed macrophages.
Project description:Diabetic kidney disease (DKD) is the leading cause of end-stage kidney diseases resulting enormous social-economic burden. Accumulated evidence has indicated that C-reactive protein (CRP) exacerbates DKD by enhancing renal inflammation and fibrosis through TGF-β/Smad3 signaling. NLRP3 inflammasome is the key sensor contributing to renal inflammation. However, whether CRP enhances inflammation in DKD via NLRP3 inflammasome related pathway remains unknown. In this study, we demonstrate that CRP promotes DKD via Smad3-mediated NLRP3 inflammasome activation as mice overexpressing human CRP gene exhibits accelerated renal inflammation in diabetic kidneys, which is associated with the activation of Smad3 and NLRP3 inflammasome. In contrast, blockade of CPR signaling with a neutralizing anti-CD32 antibody attenuates CRP-induced activation of Smad3 and NLRP3 in vitro. Importantly, genetic deletion or pharmacological inhibition of Smad3 also mitigates CRP-induced activation of NLRP3 in diabetic kidneys or in high glucose treated cells. Mechanistically, we reveal that Smad3 binds to the NLRP3 gene promoter which is enhanced by CRP. Taken together, we conclude that CRP induces renal inflammation in DKD via to the Smad3-NLRP3 inflammasome-dependent mechanism. Thus, targeting CRP or Smad3-NLRP3 pathways may be a new therapeutic potential for DKD.
Project description:Influenza A virus (IAV) infection leads to severe inflammation, and while epithelial-driven inflammatory responses occur via activation of NF-B, the factors that modulate inflammation, particularly the negative regulators are less well-defined. In this study we show that A20 is a crucial molecular switch that dampens IAV-induced inflammatory responses. Chronic exposure to low-dose LPS environment can restrict this excessive inflammation. The mechanisms that this environment provides to suppress inflammation remain elusive. Here, our evidences show that chronic exposure to low-dose LPS suppressed inflammation in A549 cells induced by IAV infection or LPS stimulationn. Chronic low-dose LPS environment increases A20 expression, which in turn positively regulates PPAR-α and -γ, thus dampens the NF-κB signaling pathway and NLRP3 inflammasome activation. Knockout of A20 abolished the inhibitory effect on inflammation. Thus, A20 and its induced PPAR-α and -γ play a key role in suppressing excessive inflammatory responses in the chronic low-dose LPS environment.
Project description:S100A8/A9 is a proinflammatory mediator released by myeloid cells during many acute and chronic inflammatory disorders. However, the precise mechanism of its release from the cytosolic compartment of neutrophils is still elusive. We report here that E-selectin-induced rapid S100A8/A9 release during inflammation occurs in a NLRP3 inflammasome-dependent fashion. Mechanistically, E-selectin engagement triggers Bruton?s tyrosine kinase dependent tyrosine phosphorylation of NLRP3. Concomitant potassium efflux via the voltage-gated potassium channel KV1.3 mediates ASC oligomerization. This is followed by caspase-1 cleavage and downstream activation of pore forming gasdermin D, enabling cytosolic S100A8/A9 to be released. Strikingly, E-selectin-mediated gasdermin D pore formation does not result in cell death, but is a transient process involving activation of the ESCRT-III membrane repair machinery. These findings do not only elucidate the molecular mechanisms of controlled S100A8/A9 release but also identify the NLRP3/gasdermin D axis as a rapid and reversible activation system in neutrophils during inflammation.
Project description:Rationale: Geranylgeranyl pyrophosphate synthase large subunit 1 (GGPPS1), a catalase downstream of the mevalonate pathway, regulates various pathological processes through balancing the production of farnesyl pyrophosphate and geranylgeranyl pyrophosphate. We sought to investigate whether GGPPS1 plays a role in mediating acute lung injury (ALI) using a mouse model of inflammation. Methods: Lipopolysaccharide (LPS) was intra-tracheally instilled to induce ALI in lung specific GGPPS1 knockout and wild-type mice. Expression of GGPPS1 in lung tissues and alveolar epithelial cells (AECs) was examined at different time points. Alveolar exudate, neutrophil infiltration, lung injury and cell death were determined. Change in global gene expression in response to GGPPS1 depletion was measured using mRNA microarray and verified in vivo and in vitro. Results: GGPPS1 levels increased significantly in lung tissues from LPS-induced ALI mice, where it showed a time- and dose-dependent increase in alveolar epithelial cells. Specific deletion of pulmonary GGPPS1 reduced the alveolar exudate and attenuated the severity of lung injury through inhibiting apoptosis of AECs. However, GGPPS1 deletion had limited effect on neutrophil counts and TNF-α levels in alveolar fluids. Deletion of GGPPS1 inhibited LPS-induced inflammasome activation, in terms of IL-1β release and pyroptosis, by down-regulating NLRP3 expression. Conclusions: Inhibition of pulmonary GGPPS1 attenuated LPS-induced ALI, predominantly by suppressing NLRP3 inflammasome activation.
Project description:Blood-brain barrier (BBB) disintegration emerges as a significant contributor to neuroinflammation; however, the biological processes governing BBB permeability under physiological conditions remain unclear. Here, we examined the potential role of NLRP3 inflammasome in BBB disruption following peripheral inflammatory challenges. Systemic lipopolysaccharide administration caused an NLRP3-dependent increase in BBB permeability and myeloid cell infiltration into the brain. Using a cell-specific, hyperactive NLRP3-expressing mouse model, we found that microglial NLRP3 activation is crucial for peripheral inflammation-induced BBB disruption. In contrast, NLRP3 and microglial gasdermin D (GSDMD) deficiency remarkably attenuated lipopolysaccharide-induced BBB breakdown. Notably, IL-1 was unnecessary for this NLRP3-GSDMD-mediated BBB disruption. Instead, microglial NLRP3-GSDMD axis specifically upregulates CXCL chemokine around BBB via producing GDF-15, recruiting Cxcr2-containing neutrophils into the brain. Neutrophil depletion and Cxcr2 blockade significantly reduced NLRP3-mediated BBB impairment. Collectively, our findings unveiled the significant role of NLRP3-driven chemokine production for BBB disintegration, suggesting a potential therapeutic target to mitigate neuroinflammation.
2024-12-30 | GSE263094 | GEO
Project description:Mogroside V protects Lipopolysaccharides-induced lung inflammation chicken via suppressing inflammation mediated by the Th17 through the gut-lung axis
Project description:The innate immune system recognizes nucleic acids as a signature of microbial infection and initiates host-protective responses, including the production of type I IFN and proinflammatory cytokines. Z-DNA binding protein 1 (ZBP1, also known as DLM-1 or DAI) was previously identified as a dsDNA binding protein, triggering DNA-mediated activation of innate immune responses. However, mice or cells lacking ZBP1 produce normal levels of type I IFN in response to dsDNA. Therefore, the classification of ZBP1 as a true DNA sensor remains to be resolved. Here, we report that the single stranded RNA virus, influenza A virus (IAV) is a trigger of the cytosolic sensor ZBP1. Sensing of IAV infection by ZBP1 engages a novel NLRP3 inflammasome pathway that is not defined by the conventions of the canonical and non-canonical NLRP3 inflammasome pathways. Surprisingly, IAV-induced cell death was not prevented by the absence of the NLRP3 inflammasome. Instead, we identified parallel contributions from pyroptosis, necroptosis and apoptosis in the execution of ZBP1-dependent cell death, mediated by the kinase RIPK3. Overall, the ability of ZBP1 to sense IAV infection signifies a point of divergence for IAV-induced programmed cell death pathways and inflammasome activation. We used microarrays to explore the gene expression profiles differentially expressed in influenza-infected bone marrow derived macrophages (BMDM) isolated from Ifnar1-/- and wild-type mice.