Microarray analysis of peripheral blood mononuclear cells isolated from patients with ANCA-associated vasculitis and healthy controls
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ABSTRACT: Patients with anti-MPO vasculitis have increased serum levels of the signalling molecule cGAMP suggestive of ongoing DNA recognition by the cGAS/STING pathway. Consistent with this gene set enrichment analysis of peripheral blood mononuclear cell transcriptomes from patients with active anti-MPO vasculitis revealed up-regulation of type 1 interferon response genes compared to healthy controls.
Project description:Autoimmune diseases are common and debilitating, but their severe manifestations could be reduced if biomarkers were available to allow individual tailoring of the potentially toxic immunosuppressive therapy required for their control. Clinically useful biomarkers have been identified using DNA microarrays in cancer but not autoimmunity. We show that transcriptional profiling of purified CD8 T cells, but not unseparated cells, identifies two distinct patient subgroups predicting long-term prognosis in two different autoimmune diseases, anti-neutrophil cytoplasmic antibody (ANCA) – associated vasculitis (AAV) and systemic lupus erythematosus (SLE). We show that genes defining the poor prognostic group are enriched for genes of the IL7R pathway, TCR signalling and those expressed by memory T cells. Furthermore, the poor prognostic group is associated with an expanded CD8 T cell memory population. These subgroups, which are also found in the normal population and can be identified by measuring expression of only three genes, raise the prospect of individualized therapy and suggest novel potential therapeutic targets in autoimmunity.
Project description:Increased T cell IL-7Rα (CD127) signaling is associated with poor prognosis in ANCA-associated vasculitis patients, whereas genes linked to T cell exhaustion such as PD-1 correlate with fewer relapses and better patient outcomes. This study characterised intrarenal CD127 and PD-1 expressing CD4+ and CD8+ T cells in mice with anti-MPO glomerulonephritis by RNA sequencing and examined the functional role of IL-7Rα in experimental glomerulonephritis mediated by anti-MPO T cell autoimmunity. There were 3,738 and 2,726 genes differentially expressed between intrarenal CD127-PD-1+ and CD127+PD-1- CD8+ and CD4+ T cells, respectively, with a substantial overlap of differentially expressed genes between CD8+ and CD4+ T cells. Both CD127-PD-1+ CD8+ and CD4+ T cells were enriched for previously described T cell exhaustion signatures that predict prognosis in autoimmune disease. As effector memory T cells drive inflammation, we blocked CD127 after the induction of anti-MPO autoimmunity. Compared with control IgG, anti-IL-7Rα antibodies limited histological injury, reduced albuminuria and reduced numbers of glomerular and interstitial leukocytes, with reduced intrarenal chemokine and pro-inflammatory cytokine expression. Intrarenal effector memory and exhausted CD4+ and CD8+ T cells are present in experimental anti-MPO glomerulonephritis. Neutralising effector memory T cells via the IL-7Rα after the induction of autoimmunity limits intrarenal inflammation and disease. IL-7Rα may be a therapeutic target in ANCA-associated vasculitis.
Project description:To study monocyte and macrophage activation in ANCA-associtated vasculitis (AAV), we performed bulk RNA sequencing of bead-selected monocytes and in vitro cultured monocyte-derived macrophages from AAV patients and healthy controls. Overview patients included for sequencing monocytes: - AAV active disease, n=4, MPO-AAV=4 - AAV remission, n=10, PR3-AAV=5, MPO-AAV=5 - Healthy controls, n=6 Overview patients included for sequencing monocyte-derived macrophages: - AAV active, n=1, PR3-AAV=1 - AAV remission, n=3, PR3-AAV=3 - Healthy controls, n=3
Project description:Purpose: The goal of this study was to compare gene expression profiles from whole blood RNA-Seq data from pediatric ANCA-associated vasculitis patients to identify mechanistic endotypes. Methods: Whole blood mRNA profiles were generated from pediatric and adult vasculitis patients using Illumina GAIIx or Hi Seq 2500 RNA-Seq. Fastq files were alinged to human genome version GRC38.91 using STAR v2.6 and count data was generated with HTSEQ v0.61p1. Counts that passed quality and minimum expression filteres were anlayzed by hierarchical clustering based on Euclidean distance, and then for differential expression with DESeq2. Results: Our workflow identified 14,156 transcripts consistently expressed in vasculitis patients. Distance hierarchcial clustering identified three groups within these pediatric samples, and two groups plus one outlier in the adult samples. The two largest pediatric clusters were used as groups for differential expression analysis with the DESeq2 package for R. DE analysis identified 3,809 differentially expressed genes between clusters. Between the two adult groups, 1,682 genes were differentially expressed. DE genes were anlayzed for enrichment using ReatomePA as the reference database. This analysis revealed that genes involved in T-cell mediated immunity are more highly expressed in pediatric patients that fell into one endotype and those involved in neutrophil and Toll-like receptor mediated inflammation are more highly expressed in pediatric patients that fell into the other endotype group. Similar results were also seen in adults. Conclusions: This study utilizes RNA-Seq data to investigate the etiologies of ANCA-associated vasculitis. Using this approach we have identified T-cell mediated immunity and Toll-like receptor mediated inflammation as potentially differing inflammatory mechanisms in both pediatric and adult vasculitis patients that do not fall along normal diagnostic criteria.
Project description:Copy number variation (CNV) has been shown to be common in regions of the genome coding for immune-related genes, and thus impacts upon polygenic autoimmunity. Low copy number of FCGR3B has recently been associated with systemic lupus erythematosus (SLE). FcγRIIIb is a glycosylphosphatidylinositol-linked, low affinity receptor for IgG found predominantly on human neutrophils. We present novel data demonstrating that both in a family with FcγRIIIb-deficiency, and in the normal population, FCGR3B CNV correlates with protein expression, with neutrophil uptake of and adherence to immune complexes, and with soluble serum FcγRIIIb. Reduced FcγRIIIb expression is thus likely to contribute to the impaired clearance of immune complexes which is a feature of SLE, explaining the association between low FCGR3B CNV and SLE that we have confirmed in a Caucasian population. In contrast, anti-neutrophil cytoplasmic antibody -associated vasculitis (AASV), a disease not associated with immune complex deposition, is associated with high FCGR3B CN. Thus we define a role for FCGR3B CNV in immune complex clearance, a function which may explain why low FCGR3B CNV is associated with SLE but not AASV. This is the first report of an association between disease-related gene CNV and variation in protein expression and function that may contribute to autoimmune disease susceptibility.
Project description:These data are part of a body of work exploring the effect of IgG from patients with ANCA vasculitis on human monocytes in vitro. Please see the relevant publication for a full description.
Project description:In patients with GN or vasculitis, ANCAs are directed against proteinase 3 (PR3) or myeloperoxidase (MPO). The differences between PR3-ANCA-associated vasculitis (AAV) and MPO-AAV described in the past have been supplemented during the last decade. In this review, we discuss the differences between these two small-vessel vasculitides, focusing especially on possible etiologic and pathophysiologic differences. PR3-AAV is more common in northern parts of the world, whereas MPO-AAV is more common in southern regions of Europe, Asia, and the Pacific, with the exception of New Zealand and Australia. A genetic contribution has been extensively studied, and there is a high prevalence of the HLA-DPB1*04:01 allele in patients with PR3-AAV as opposed to patients with MPO-AAV and/or healthy controls. Histologically, MPO-AAV and PR3-AAV are similar but show qualitative differences when analyzed carefully. Clinically, both serotypes are difficult to distinguish, but quantitative differences are present. More organs are affected in PR3-AAV, whereas renal limited vasculitis occurs more often in patients with MPO-AAV. For future clinical trials, we advocate classifying patients by ANCA serotype as opposed to the traditional disease type classification.
Project description:The etiopathogenesis underlying myeloperoxidase anti-neutrophil cytoplasmic antibody associated glomerulonephritis (MPO-AAGN) remains incompletely understood. Furthermore, there are only limited treatment options and treatment resistance of MPO-AAGN is still a common problem. To identify new targeted treatment options, intrarenal single-cell RNA sequencing (scRNA-seq) was applied to kidney biopsies from MPO-AAGN patients and control health kidney tissues to define the transcriptomic landscape at single-cell resolution. Intrarenal scRNAseq was also applied to a pre-clinical mouse model of MPO-AAGN to show that this model of disease can be used to trial new targeted treatments. NF-κB pathway activation was confirmed in a variety of kidney cells in MPO-AAGN patients. Kidney infiltrating immune cells of MPO-AAGN patients were mainly enriched in inflammatory pathways including TNF signaling, IL-17 signaling and NOD-like receptor signaling. These findings were similar in our pre-clinical mouse model of MPO-AAGN. Furthermore, there was an overexpression of inflammasome related genes (AIM2, IFI16) in MPO-AAGN patients. A dynamic gene expression in glomerular resident cells was observed in MPO-AAGN, including increased expression of several genes, including CD9 and SPARC, which were closely related to parietal epithelial hyperplasia and crescent formation and lesion progression. Importantly, overexpression of HSP90AA1 in non-focal mesangial cells and endothelial cells was found and the expression of several chemokines (CCL20, CXCL3, CXCL8, CXCL1, CCL2) were upregulated in non-focal proximal tubule cells. Moreover, MPO-AAGN patients with treatment resistance had higher proportions of kidney infiltrating classical monocytes and CD8+ T cells. Elevated expression of SPARC and LAMA4 in mesangial cells, IL33 in endothelial cells, and CFL1 in several cell clusters (proximal tubule cells, loop of Helen, macrophages) were observed in MPO-AAGN patients with treatment resistance when compared with patients who achieved remission after induction therapy. These results offer new insight into the pathogenesis of the progression and treatment resistance MPO-AAGN. We have identified new therapeutic targets for MPO-AAGN that can be tested in a pre-clinical model of disease.
Project description:Abnormal DNA sensing mediated by cGAS-STING is pivotal for host defenses. Activation of cGAS-STING triggered interferon dependent anti-viral functions have been well characterized but this function is missing in more ancient animal STING. Whether more primitive animal STING can generate non-canonical pathway dependent anti-viral activities is unclear. Here, we discovered potent anti-viral activities of ancient animal STING in the absence of all three canonical pathways. Various ancient animal STING-stimulated genes (ASGs) with unique and synergistic anti-viral functions were induced by this newly identified pathway through an ancient transcriptional regulator IRF1 and a separate unique functional domain in STING. Some ASGs are both necessary and sufficient as host restriction factors and under positive selection during animal evolution. Diverse viruses have developed strategies to evade this newly identified cGAS-STING function. Our findings reveal an ancient, conserved cGAS-STING pathway mediated anti-viral activities through previously unrecognized cellular restriction factors. Various animal STING expression in HEK293T cells could up regulate a series of genes. To screen candidates for anti-viral host factors stimulated by STING in the absence of the known canonical pathways, we identified the factors that were regulated by the IFN induction and NF-κB induction-defective Nematostella vectensis (N.v) STING and the IFN induction-defective human STING variant (H.s STING ΔCTT) by microarray assay. Multiple rounds of confirmative and comparative experiments narrowed down to 10 such factors, i.e., ancient animal STING stimulated genes (ASGs). ASGs were significantly upregulated by STING activation in various human cell types.