{
  "abstract": "Introduction Gastroesophageal reflux disease (GERD) is a common manifestation of scleroderma, second to Raynaud’s phenomenon. Bile acid-induced injury to the distal oesophageal mucosa is a known risk factor for Barrett’s oesophagus and in turn, increases the risk of oesophageal cancer. Nonetheless, it is unclear whether the cellular and molecular events induced by acid injury may contribute to the loss of immunological tolerance and/or other aspects of the pathogenesis of SSc.Material and Methods BA treatment of oesophageal cells: Normal oesophageal epithelial cells (Het1A) were serum-starved in media+1%FBS for 48 hours, then cells exposed to acidified media (pH 4.0- hydrochloric acid, 100µM bile salts) for 10 minutes daily for five consecutive days. 24 hours after the 5th BA exposure, cells were lysed for RNA to perform RNA sequencing and RT-qPCR. Protein expression was assessed by immunofluorescence. Scratch wound assay was performed to assess changes in cellular motility in epithelial cells. For co-culture experiments, healthy and SSc fibroblasts were grown on 0.4µm baskets above serum-starved Het1A cells, with baskets removed during 10 minutes bile acid treatments.Results Het1A exposed to BA lost their cobblestone appearance and acquired mesenchymal characteristics (change in orthogonal diameters ratio p<0.0001). RNA-sequencing identified 788 genes differentially expressed to untreated control (p<0.05, t test), with GO pathways enriched for type I interferon (IFN) signalling, response to TGF-B, EMT, and oxidative stress in cells after chronic BA exposure. RT-qPCR confirmed significant increased IFN and EMT signalling with increased expression of STAT1 (p<0.0001), OAS1 (p=0.0004), ISG15 (p=0.002) and IFIT1 (p<0.0001), vimentin (p=0.001) and N-cadherin (p=0.05) and confirmed by immunofluorescence. Cross-platform comparison of the Het1A transcriptome with publicly available SSc oesophageal biopsy gene showed a shared upregulation of genes associated with all the SSc intrinsic signatures, and shared pathways including regulation of immune response, leukocyte activation, response to wounding, cellular response to stress and microtubule cytoskeleton, suggested that acid reflux may contribute to several processes detected in SSc oesophageal biopsies. Scratch assay confirmed increased wound healing with BA (p<0.0001). Co-culture of Het1A cells with SSc fibroblasts enhanced both type I IFN and EMT gene expression compared to healthy dermal fibroblast cultures.Conclusions Our study suggests that bile acid exposure may contribute as environmental trigger for early molecular events in SSc pathogenesis, including innate immune activation and EMT. These results may inform future research into the interaction of exposome and predisposing genetic background in the pathogenesis of tissue damage in systemic sclerosis.",
  "authors": [
    {
      "affiliations": [
        "Leeds Institute of Rheumatic and Musculoskeletal Medicine, Leeds, United Kingdom"
      ],
      "name": "Safoura Zahed Mohajerani"
    },
    {
      "affiliations": [
        "Leeds Institute of Rheumatic and Musculoskeletal Medicine, Leeds, United Kingdom"
      ],
      "name": "Ala Altaie"
    },
    {
      "affiliations": [
        "Leeds Institute of Rheumatic and Musculoskeletal Medicine, Leeds, United Kingdom",
        "Immuno-Rheumatology Unit, Roma, Italy"
      ],
      "name": "Marco Minerba"
    },
    {
      "affiliations": [
        "Leeds Institute of Biological Science, Leeds, United Kingdom"
      ],
      "name": "Kin Man Suen"
    },
    {
      "affiliations": [
        "Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom"
      ],
      "name": "Christopher Black"
    },
    {
      "affiliations": [
        "Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom"
      ],
      "name": "Lesley-Anne Bissell"
    },
    {
      "affiliations": [
        "Department of Medicine, Division of Rheumatology, Chicago, USA",
        "Department of Preventive Medicine, Chicago, USA",
        "Institute for Public Health and Medicine, Chicago, USA"
      ],
      "name": "Monique Hinchcliff"
    },
    {
      "affiliations": [
        "Leeds Institute of Biological Science, Leeds, United Kingdom"
      ],
      "name": "John E Ladbury"
    },
    {
      "affiliations": [
        "Leeds Institute of Rheumatic and Musculoskeletal Medicine, Leeds, United Kingdom",
        "NIHR Leeds Biomedical Research Centre, Leeds United Kingdom"
      ],
      "name": "Rebecca L Ross"
    },
    {
      "affiliations": [
        "Leeds Institute of Rheumatic and Musculoskeletal Medicine, Leeds, United Kingdom",
        "NIHR Leeds Biomedical Research Centre, Leeds United Kingdom"
      ],
      "name": "Francesco Del Galdo"
    }
  ],
  "title": "P.163 Acid reflux triggers type I interferon and cause epithelial-mesenchymal transition in oesophageal epithelial cells may contribute to the pathogenesis of oesophageal involvement in systemic sclerosis",
  "uid": "a65a02fb-823d-535a-a148-43712a63ae86"
}