Project description:This study invesigates the effects of neutrophil extracellular traps (NETs) on articular cartilage degredation and resulting autoimmune responses in rheumatoid arthritis.
Project description:Introduction: Autoreactivity to histones is a pervasive feature of several human autoimmune disorders including systemic lupus erythematosus (SLE). Specific post-translational modifications (PTMs) of histones within neutrophil extracellular traps (NETs) may potentially drive the process by which tolerance to these chromatin-associated proteins is broken. We hypothesized that NETs and their unique histone PTMs might be capable of inducing autoantibodies that target histones. Methods: We developed a novel and efficient method for the in vitro production, visualization, and broad profiling of histone-PTMs of human and murine NETs. We also immunized Balb/c mice with murine NETs and profiled their sera on autoantigen and histone peptide microarrays for evidence of autoantibody production to their immunogen. Results: We confirmed specificity toward acetyl-modified histone H2B as well as to other histone PTMs in sera from patients with SLE known to have autoreactivity against histones. We observed enrichment for distinctive histone marks of transcriptionally silent DNA during NETosis triggered by diverse stimuli. However, NETs derived from human and murine sources did not harbor many of the PTMs toward which autoreactivity was observed in patients with SLE or in MRL/lpr mice. Further, while murine NETs were weak autoantigens in vivo, there was only partial overlap in the IgG and IgM autoantibody profiles induced by vaccination of mice with NETs and those seen in patients with SLE. Conclusions: Isolated in vivo exposure to NETs is insufficient to break tolerance and may involve additional factors that have yet to be identified. Serum samples from 20 systemic lupus erythematosis patients were run on the Human Epigenome Microarray Platform V1.0 (HEMP; a single-color platform), in order to profile their autoantibodies against a library of post-translationally modified histone peptides. These 20 samples were randomly selected from a larger cohort previously profiled (data not shown) on the Utz Lab Whole Protein Autoantigen Array V2.0 (a single-color platform), where 14 were histone-reactive and 6 were histone-nonreactive. Control sera from 9 healthy adults and a positive control comprising a mixture of autoimmune sera with defined reactivities, were also run on HEMP V1.0. Together, these samples comprise the data appearing in Figures 1 and S1 (IgG and IgM isotype reactivity profiles, respectively), identifying IgG reactivity to 9 peptides that significantly distinguish histone-reactive from -nonreactive sera among 96 peptides profiled. For data appearing in Figure 5, serum samples from a total of 6 Balb/c mice, consisting of two treatment groups, NETs (Neutrophil Extracellular Traps) and NETs + CRAMP (cathelicidin-related antimicrobial peptide) were collected monthly over a 3-month period, along with a zero time point. These samples were compared with a positive control consisting of serum collected from a MLR/lpr mice exhibiting lupus-like symptoms, and a negative control with no serum. The 0, 1 and 2 month time points were profiled on the Utz Lab Whole Protein Autoantigen Array V2.0 and are shown in Figure 5A-B, while the 1 and 3 month time points were profiled on HEMP V1.0 arrays and shown in Figure 5E. All samples were run once with no replicates.
Project description:Introduction: Autoreactivity to histones is a pervasive feature of several human autoimmune disorders including systemic lupus erythematosus (SLE). Specific post-translational modifications (PTMs) of histones within neutrophil extracellular traps (NETs) may potentially drive the process by which tolerance to these chromatin-associated proteins is broken. We hypothesized that NETs and their unique histone PTMs might be capable of inducing autoantibodies that target histones. Methods: We developed a novel and efficient method for the in vitro production, visualization, and broad profiling of histone-PTMs of human and murine NETs. We also immunized Balb/c mice with murine NETs and profiled their sera on autoantigen and histone peptide microarrays for evidence of autoantibody production to their immunogen. Results: We confirmed specificity toward acetyl-modified histone H2B as well as to other histone PTMs in sera from patients with SLE known to have autoreactivity against histones. We observed enrichment for distinctive histone marks of transcriptionally silent DNA during NETosis triggered by diverse stimuli. However, NETs derived from human and murine sources did not harbor many of the PTMs toward which autoreactivity was observed in patients with SLE or in MRL/lpr mice. Further, while murine NETs were weak autoantigens in vivo, there was only partial overlap in the IgG and IgM autoantibody profiles induced by vaccination of mice with NETs and those seen in patients with SLE. Conclusions: Isolated in vivo exposure to NETs is insufficient to break tolerance and may involve additional factors that have yet to be identified. Serum samples from 20 systemic lupus erythematosis patients were run on the Human Epigenome Microarray Platform V1.0 (HEMP; a single-color platform), in order to profile their autoantibodies against a library of post-translationally modified histone peptides. These 20 samples were randomly selected from a larger cohort previously profiled (data not shown) on the Utz Lab Whole Protein Autoantigen Array V2.0 (a single-color platform), where 14 were histone-reactive and 6 were histone-nonreactive. Control sera from 9 healthy adults and a positive control comprising a mixture of autoimmune sera with defined reactivities, were also run on HEMP V1.0. Together, these samples comprise the data appearing in Figures 1 and S1 (IgG and IgM isotype reactivity profiles, respectively), identifying IgG reactivity to 9 peptides that significantly distinguish histone-reactive from -nonreactive sera among 96 peptides profiled. For data appearing in Figure 5, serum samples from a total of 6 Balb/c mice, consisting of two treatment groups, NETs (Neutrophil Extracellular Traps) and NETs + CRAMP (cathelicidin-related antimicrobial peptide) were collected monthly over a 3-month period, along with a zero time point. These samples were compared with a positive control consisting of serum collected from a MLR/lpr mice exhibiting lupus-like symptoms, and a negative control with no serum. The 0, 1 and 2 month time points were profiled on the Utz Lab Whole Protein Autoantigen Array V2.0 and are shown in Figure 5A-B, while the 1 and 3 month time points were profiled on HEMP V1.0 arrays and shown in Figure 5E. All samples were run once with no replicates.
Project description:We performed a comparison of transcriptome between monocyte-derived dendritic cells (moDC) cultured with neutrophil extracellular traps (NETs) from healthy donors or type 1 diabetes (T1D) patients. The source of moDCs is healthy donors and T1D patients
Project description:Pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome is characterized by flares of sterile arthritis with neutrophil infiltrate and the overproduction of Interleukin (IL)-1β. The purpose of this study was to elucidate the potential role of neutrophil subsets and neutrophil extracellular traps (NETs) in the pathogenesis of PAPA. The transcriptome of PAPA normal-dense neutrophils, autologous LDGs, and healthy control normal-dense neutrophils was characterized using RNASeq. The transcriptome of a PAPA skin biopsy and a healthy control skin sample was elucidated using RNASeq.
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.
Project description:This SuperSeries is composed of the following subset Series: GSE32542: Murine serum reactivity to common autoantigens in response to immunization with neutrophil extracellular traps GSE32543: Human and murine serum reactivity to specific histone posttranslational modifications in neutrophil extracellular traps Refer to individual Series
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.
Project description:Our group has proposed that low-density granulocytes (LDGs) play an important role in lupus pathogenesis, as they can damage endothelial cells and synthesize increased levels of proinflammatory cytokines and type I interferons. LDGs have a heightened capacity to synthesize neutrophil extracellular traps (NETs). NETs from LDGs display increased levels of bactericidal and immunostimulatory proteins, such as the cathelicidin LL37 and externalize double-stranded DNA (dsDNA). Lupus netting LDGs have increased capacity to kill endothelial cells and expose IL-17. Through NETosis, lupus neutrophils stimulate plasmacytoid DCs to synthesize IFN-?. Our results further expand the potential pathogenic role of aberrant lupus neutrophils through a NET-mediated effect. We used microarrays to analyze the gene expression of neutrophils in healthy and lupus patients, and of low-density granulocytes in lupus patients. Human neutrophils and LDGs were isolated from PBMCs. RNA from healthy neutrophils, lupus neutrophils and lupus LDGs was extracted and processed for hybridization on Affymetrix microarrays.