Neutrophil extracellular traps have auto-catabolic activity and produce mononucleosome-associated circulating DNA
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PROVIDER: EGAS00001006759 | EGA |
REPOSITORIES: EGA
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Project description:Post-injury dysfunction of humoral immunity accounts for infections and poor outcome in cardiovascular diseases. Immunoglobulin A (IgA), the most abundant mucosal antibody is produced by plasma B cells in intestinal Peyer’s patches (PP) and lamina propria. Here, we show that stroke and myocardial ischemia (MI) patients had strongly reduced IgA blood levels. This was phenocopied in experimental mouse models where decreased plasma and fecal IgA were accompanied by rapid and macroscopic shrinkage of PP caused by substantial B cell loss. Stroke/MI triggered neutrophils to release neutrophil extracellular traps (NETs). Depletion of neutrophils, NET-degradation, or blockade of NET-release inhibited PP shrinkage and loss of B cells and IgA in stroke mice. Also, stroke and MI patients had higher amounts of circulating NETs, correlating with reduced IgA levels. Strikingly, stroke patients treated with DNase-I had reduced circulating NETs and stable IgA levels. Our results unveil how tissue-injury-triggered systemic NET release disrupts physiological IgA secretion and how this can be inhibited in patients.
2024-03-17 | GSE254410 | GEO
Project description:Neutrophil extracellular traps (NETs) contribute to inflammatory pathogenesis, especially in infectious and cardiovascular diseases. H2 gas acts as an antioxidant and has been clinically and experimentally proven to ameliorate inflammation. Therefore, we investigated whether H2 gas could inhibit NET formation associated with excessive neutrophil activation. Phorbol-12-myristate-13-acetate (PMA)-stimulated human neutrophils exposed to H2 exhibited reduced citrullination of histones, membrane disruption by chromatin complexes, and release of NET components over controls. Mechanistically, H2 suppressed the phosphorylation of Ser-139 residue in H2AX, a marker of DNA damage, thereby reducing the expression of CXC-chemokine receptor 4 (CXCR4) in PMA-stimulated neutrophils. Along with the upregulation of CXCR4, the intracellular content of myeloperoxidase (MPO) and the production of MPO-derived hypochlorous acid (HOCl) was increased; however, these effects were markedly suppressed in H2-exposed cultures. Thus, H2 neutralized HOCl produced by the oxidative burst, inhibited DNA damage, and subsequently inhibited NET formation. We further confirmed that inhalation of H2 inhibited the formation and release of NET components in the blood and bronchoalveolar lavage of a lipopolysaccharide-induced sepsis model in mice and aged minipigs. Therefore, H2 therapy has the potential to be a new therapeutic agent for inflammatory diseases involving NETs associated with excessive neutrophil activation.
2022-02-23 | GSE178883 | GEO
Project description:Sterile tissue injury after stroke causes lymphocyte contraction in lymphoid tissues and may decrease circulating IgA-levels. Intestinal Peyer’s patches (PP) harbor large numbers of IgA+ B cell precursors and plasma cells. Whether and how tissue injury triggers PP-B cell death, thereby mediating IgA-loss, is unknown. We found decreased circulating IgA levels in stroke and myocardial infarction patients. Experimental stroke and myocardial infarction in mice phenocopied the human situation. Decreased plasma and fecal IgA were accompanied by rapid and macroscopic shrinkage of PP caused by substantial losses of PP-resident IgA+ precursors and plasma cells in mice. Tissue injury induced neutrophil activation endowed with the release of toxic neutrophil extracellular traps (NETs). Antibody-mediated or genetically- induced neutrophil loss, digestion of NETs, or inhibition of their release by the Gasdermin D blockade completely prevented lymphocyte loss and PP shrinkage. We also identified NETs in the plasma of stroke and myocardial infarction patients. Hence, tissue injury induces systemic NET-release, which might be targeted to maintain immune homeostasis at mucosal barriers.
2024-02-28 | PXD044644 | Pride
Project description:Abstract. Objectives: Neutrophil extracellular traps (NETs) are extracellular lattices composed of nucleic material bound to neutrophil granule proteins. NETs may play pathogenic roles in development and severity of autoimmune diseases such as systemic lupus erythematosus (SLE), at least in part, through induction of type I interferon (IFN) responses via externalization of oxidized immunostimulatory DNA. A distinct subset of SLE proinflammatory neutrophils (low density granulocytes; LDGs) displays enhanced ability to form proinflammatory NETs that damage the vasculature. We assessed whether NET-bound RNA can contribute to inflammatory responses in endothelial cells and the pathways that mediate this effect. Methods: Expression of newly-synthesized RNA was quantified if healthy control and lupus NETs. The ability of endothelial cells to take up NET-bound RNA and downstream induction of type I IFN responses was quantified. RNAs present in NETs were sequenced and specific small RNAs were tested for induction of endothelial type I IFN pathways. Results: NETs extruded newly-synthesized RNA that was internalized by endothelial cells and this was enhanced when NET nucleic acids were oxidized, particularly in lupus LDG NETs. Internalization of NET-bound total RNA by endothelial cells was dependent on endosomal TLRs and the actin cytoskeleton and induced type I IFN stimulated genes (ISGs). This ISG induction was dependent on NET-associated miR-let7b, a small RNA expressed at higher levels in LDG NETs, which acted as a TLR7 agonist. Conclusion: These results highlight underappreciated roles for small RNAs externalized in NETs in the induction of proinflammatory responses in vascular cells, with implications to lupus vasculopathy.
2023-07-31 | GSE160143 | GEO
Project description:Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Neutrophil extracellular traps (NETs) are a network structure composed of loose chromatin and embedded with multiple proteins. Here, we observed increased NETs deposition in the glomeruli of DKD patients and diabetic mice (streptozotocin-induced or db/db mice). After degrading NETs with DNase I, diabetic mice exhibited attenuated glomerulopathy and glomerular endothelial cell (GEC) injury. We also observed alleviated glomerulopathy and GEC injury in peptidylarginine deiminase 4 (PAD4)-knockout mice with streptozotocin-induced diabetes. In vitro, NET-induced GEC pyroptosis was characterized by pore formation in the cell membrane, dysregulation of multiple genes involved in cell membrane function, and high expression of pyroptosis-related proteins. Strengthening the GEC surface charge by oleylamine significantly inhibited NET-induced GEC pyroptosis. These results indicate that NET-induced alterations in GEC charge are associated with GEC pyroptosis in the pathogenesis of DKD and suggest that NETs are a potential therapeutic target for DKD.
2022-09-01 | GSE189875 | GEO
Project description:Preterm infants are highly susceptible to late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) but specific biomarkers for diagnosis and effective treatment are lacking. Neutrophil extracellular traps (NETs) are related to sepsis in adults but not investigated in infant conditions. This is the first proteome study to document that circulating NETs are involved in neonatal LOS and NEC. cfDNA and NET proteins may provide new potential diagnostic markers for these diseases.
2018-03-05 | PXD004082 | Pride
Project description:Using RNA-sesq to assess effects of NET exposure under different activation conditions, and assessing effects of homozygosity vs. nullizygosity for the Act1 D10N genotype
2019-11-19 | GSE121315 | GEO
Project description:Neutrophils have an important role in rapid antimicrobial defenses against and resolution of urinary tract infections (UTIs). We show that a mechanism known as neutrophil extracellular trap (NET) formation is a strategy to combat pathogens in the urinary tract. Viscous aggregates that were present in human urine sediments revealed high extracellular DNA content. The DNA formed a scaffold to which antimicrobial effector proteins derived from different neutrophil subcellular compartments bound. Treatment with deoxyribonuclease I solubilized these structures. We observed massive proteolytic degradation in the NETs with apparently dominant roles for the neutrophil granule proteases elastase, proteinase 3, and cathepsin G. In a UTI case with Staphylococcus aureus as the infectious agent, high abundance of autolysins and immune evasion factors in a cell-free NET extract suggested that controlled cell wall autolysis plays a role in derailing the host immune response and allows some bacterial cells to survive following entrapment in NETs.
2017-03-31 | MSV000080847 | MassIVE
Project description:Neutrophil recruitment and activation are hallmarks of the prevalent inflammatory disease, periodontitis. However, the mechanisms by which neutrophils contribute to in inflammatory bone destruction remain unclear. Herein, we document that neutrophil extracellular traps (NETs) have a direct role in mediating inflammatory pathology. In an established animal model of periodontitis, we demonstrate that genetic or pharmacologic inhibition of NETs formation, or removal of NETs by DNase-Ⅰ, alleviates inflammatory bone loss in vivo. Investigating the mechanisms by which NETs drive periodontal inflammation, we find that extracellular histones have a direct role in disease progression. Consistent with findings in animal models, histones bearing classic NET-associated post-translational modifications are correlated with disease severity and are significantly elevated in local lesions and systemic circulation of patients with periodontitis. Our work reveals NETs-associated components as pathogenic mediators, potential biomarkers, and therapeutic targets for periodontitis.
2023-05-23 | GSE228021 | GEO
Project description:Neutrophil Extracellular Traps (NETs) are structures consisting of chromatin and antimicrobial molecules that are released by neutrophils during a form of regulated cell death called NETosis. NETs trap invading pathogens, promote coagulation and activate myeloid cells to produce Type I interferons (type I IFN), proinflammatory cytokines that regulate the immune system. The mechanism of NET recognition by myeloid cells is not yet clearly identified. Here we show that macrophages and other myeloid cells phagocytose NETs. Once in phagosomes, NETs translocate to the cytosol, where they activate the DNA sensor cyclic GMP-AMP synthase (cGAS) and induce type I IFN expression. cGAS recognizes the DNA backbone of NETs. Interestingly, the NET associated serine protease Neutrophil Elastase (NE) mediates the activation of the pathway. We confirmed that NETs activate cGAS in vivo. Thus, our findings identify cGAS as a major sensor of NETs, mediating the immune activation during infection and in auto-immune diseases.
2021-02-18 | PXD015579 | Pride