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Downregulation of miR-193b in systemic sclerosis regulates the proliferative vasculopathy by urokinase-type plasminogen activator expression
  1. Naoki Iwamoto1,2,
  2. Serena Vettori1,
  3. Britta Maurer1,
  4. Matthias Brock1,
  5. Elena Pachera1,
  6. Astrid Jüngel1,
  7. Maurizio Calcagni3,
  8. Renate E Gay1,
  9. Michael L Whitfield4,
  10. Jörg H W Distler5,
  11. Steffen Gay1,
  12. Oliver Distler1
  1. 1Division of Rheumatology, Center of Experimental Rheumatology, University Hospital and Zurich Center of Integrative Human Physiology (ZIHP), Zurich, Switzerland
  2. 2Unit of Translational Medicine, Department of Immunology and Rheumatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
  3. 3Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
  4. 4Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
  5. 5Department of Internal Medicine 3, Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany
  1. Correspondence to Dr Oliver Distler, Division of Rheumatology, University Hospital Zurich, Gloriastr. 25, Zürich 8091, Switzerland; Oliver.Distler{at}usz.ch

Abstract

Objectives To investigate the role of microRNA-193b-3p (miR-193b) in the vascular pathophysiology of systemic sclerosis (SSc).

Methods Expression of miR-193b in skin biopsies and fibroblasts from patients with SSc and normal healthy (NH) controls were determined by real-time PCR. Transfection with miR-193b precursor and inhibitor were used to confirm targets of miR-193b. Proliferative effects of urokinase-type plasminogen activator (uPA) were determined by water-soluble tetrazolium salt-1 assay and by analysis of proliferating cell nuclear antigen expression. Fluorescence activated cell sorting analysis was performed to investigate the effect of uPA on apoptosis. For inhibition of the uPA-cellular receptor for uPA (uPAR) pathway, uPAR neutralising antibodies and low molecular weight uPA were used.

Results We found that miR-193b was downregulated in SSc fibroblasts and skin sections as compared with NH controls. The expression of miR-193b was not affected by major profibrotic cytokines and hypoxia. Induction of miR-193b in SSc fibroblasts suppressed, and accordingly, knockdown of miR-193b increased the levels of messenger RNA and protein for uPA. uPA was found to be upregulated in SSc as compared with NH controls in a transforming growth factor-β dependent manner, and uPA was strongly expressed in vascular smooth muscle cells in SSc skin section. Interestingly, uPA induced cell proliferation and inhibited apoptosis of human pulmonary artery smooth muscle cells, and these effects were independent of uPAR signalling.

Conclusions In SSc, the downregulation of miR-193b induces the expression of uPA, which increases the number of vascular smooth muscle cells in an uPAR-independent manner and thereby contributes to the proliferative vasculopathy with intimal hyperplasia characteristic for SSc.

  • Systemic Sclerosis
  • Arterial Hypertension
  • Autoimmune Diseases

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