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:This study investigates the role of DDX3X SUMOylation in the activation of the NLRP3 inflammasome during sepsis. We demonstrate that SUMOylation of DDX3X, regulated by the SUMO protease SENP1, is a crucial trigger for NLRP3 inflammasome activation. In endotoxemia and sepsis models, the absence of SENP1 in macrophages and mice led to increased NLRP3 inflammasome activation. Mechanistically, DDX3X SUMOylation promoted the interaction of NLRP3 at lysine 118, inhibiting K48-conjugated ubiquitination and subsequent degradation of NLRP3 by the deubiquitinase OTUD6A, resulting in enhanced oligomerization of NLRP3. In murine adoptive transfer experiments, macrophages expressing the SUMOylation-inhibiting mutation DDX3X-K118R suppressed NLRP3 inflammasome activation, providing protection against LPS-induced inflammatory lung injury. These findings suggest that SENP1-mediated DDX3X deSUMOylation regulates NLRP3 inflammasome activation, offering a potential therapeutic avenue to mitigate NLRP3-induced inflammation.
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