{
  "abstract": "Introduction Patients with systemic sclerosis (Scleroderma; SSc) are characterised by profound vasculopathy and a frequent presence of type I interferon profile that remains to be fully understood. Here, we demonstrate that anti-topoisomerase 1 antibodies (ATA) are a major immunological driver of these disease manifestations.Material and Methods Serum was obtained from ATA-positive SSc patients (n = 20) and healthy controls (HC, n = 10). Individual, and structurally intact domains of TOP1 were produced in E. coli. The TOP1 fragments were bound to Sepharose columns to purify ATA. The REEAD assay was used to test the bioactivity of ATA and TOP1. Endothelial cells, THP-1 cells, and lung biopsies were stimulated with ATA to test for a type 1 IFN profile.Results In cell-free systems, ATA was demonstrated to inhibit the DNA relaxation activity of TOP1 and induce TOP1-dependent DNA nicking.Purified ATA from SSc patients, in contrast to healthy control IgG, entered endothelial cells and THP-1 macrophage cells. Confocal microscopy showed ATA to be in direct contact with TOP1 in the nucleus and mitochondria. Purifying the nuclear fraction of cells exposed to ATA revealed that intracellular ATA inhibits the endogenous TOP1 enzymatic activity.ATA’s ability to induce genomic instability was associated with phosphorylation of the STimulator of INterferon Genes (STING) pathway and increased type I interferon and CXCL10 production in endothelial cells and THP1 cells. Using a HEK-Blue assay, we confirmed that the secreted type I IFN was bioactive.The involvement of the cGAS-STING pathway was explored using knockout cell lines, where cGAS knockout cells showed a significant decrease in CXCL10 production. In contrast, in STING knockout cells, the CXCL10 secretion was almost completely absent. A deeper characterisation of the type I IFN profile was sought via bulk RNA sequencing of endothelial cell cultures, confirming that ATA induced significant transcriptional changes, with upregulation of an array of genes mapping to the type 1 IFN signature.Our studies investigating a complex ex vivo model using human lung biopsies showed that incubation with ATA also caused a marked increase in IFNb and CXCL10 synthesisConclusions Our studies support the potential pathogenic role of ATA in penetrating the cell membrane and deleteriously interacting with and altering the function of intracellular TOP1. This effect subsequently promotes interferon synthesis by engaging the cGAS-STING DNA-sensing pathway within the cell.Collectively, our results strongly suggest that in patients with SSc with ATA, this hallmark autoantibody has a central pathogenic role.",
  "authors": [
    {
      "affiliations": [
        "Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark"
      ],
      "name": "Bent Deleuran"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Maithri Aspari"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark",
        "Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Celine Theisen"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Jakob Hauge Mikkelsen"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Emilia Holm"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Sören Magnus Morische"
    },
    {
      "affiliations": [
        "Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark",
        "Department of Clinical Medicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Esben Næser"
    },
    {
      "affiliations": [
        "Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark",
        "Department of Clinical Medicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Klaus Søndergaard"
    },
    {
      "affiliations": [
        "Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Sarah Barslund Petersen"
    },
    {
      "affiliations": [
        "Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Josephine Geertsen Keller-Socin"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Mikkel Roland Holst"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Morten Schallburg Nielsen"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark",
        "Department of Clinical Medicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Malene Hvid"
    },
    {
      "affiliations": [
        "Department of Clinical Medicine, Aarhus University, Aarhus, Denmark",
        "Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark"
      ],
      "name": "Trine-Line Korsholm"
    },
    {
      "affiliations": [
        "Centre for Rheumatology, Department of Inflammation and Rare Diseases, Division of Medicine, University College London, London, UK"
      ],
      "name": "Voon Voon Ong"
    },
    {
      "affiliations": [
        "Centre for Rheumatology, Department of Inflammation and Rare Diseases, Division of Medicine, University College London, London, UK"
      ],
      "name": "Christopher Denton"
    },
    {
      "affiliations": [
        "Centre for Rheumatology, Department of Inflammation and Rare Diseases, Division of Medicine, University College London, London, UK"
      ],
      "name": "David Abraham"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark",
        "Faculty of Medicine, Hacettepe University, Ankara, Turkey"
      ],
      "name": "Elif Hatipoglu"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Søren Paludan"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Christian Brix Folsted Andersen"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Joanna Maria Kalucka"
    },
    {
      "affiliations": [
        "Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Cinzia Tesauro"
    },
    {
      "affiliations": [
        "Department of Biomedicine, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Stinne Greisen"
    },
    {
      "affiliations": [
        "Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark"
      ],
      "name": "Birgitta Knudsen"
    }
  ],
  "title": "OC.29 Anti-topoisomerase-1 autoantibodies induce type I interferon through the cGAS-sting pathway",
  "uid": "2d365190-ed85-5e44-b718-051ac7cd9a0e"
}