{
  "abstract": "Introduction Pulmonary arterial hypertension (PAH) is a devastating disease characterised by remodelling of the pulmonary arteries, leading to right heart failure and death. The most common cause is a mutation in the bone morphogenetic protein receptor 2 (BMPR2), which plays a key role in disrupting the BMP/TGF-B pathway. The BMP pathway is negatively regulated by the HECT E3 ubiquitin ligase SMURF1. However, its lack of druggable binding site makes it difficult to target therapeutically.Hypothesis We hypothesised that increased SMURF1 expression contributes to the pathogenesis of PAH by negatively regulating BMP signalling, and that inhibiting SMURF1 will augment BMP signalling and reverse PAH-associated phenotype.Aim This study aims to: (1) Investigate the SMURF1 expression level in the pulmonary vasculature; (2) discover SMURF1 inhibitors using a large-scale screen; (3) determine their mechanism of action; and (4) assess their therapeutic potential in experimental models of PAH by examining effects on BMP signalling and cell phenotype.Methods Pulmonary tissue samples from patients undergoing transplantation (both PAH and controls) were examined to determine SMURF1 expression level. A time resolved fluorescence energy transfer (TR-FRET) assay designed to measure SMURF1 self-ubiquitylation and screen of 1.1 million compounds. Primary hits were then subjected to rationalisation and further analysis to identify specific inhibitors of SMURF1. Crystal structures of SMURF1 and SMURF2 in both ligand bound and ligand unbound, were determined at resolution from 2.05 to 2.75 Å. The interaction between identified inhibitors and their targets was validated using a split-CAT system. Finally, the effect of SMURF1 inhibition on signaling pathways and cellular phenotype was investigated in pulmonary endothelial cells and smooth muscle cells. In vivo studies were conducted using rat models of PAH induced by monocrotailne and sugan hypoxia.Results Increased SMURF1 expression was observed in the pulmonary vessel in patients with PAH compared to controls. Selective SMURF1 inhibitors were identified through compound screening. Structural studies showed that inhibitor binding induced α-helix elongation over a glycine hing, restricting catalytic activity. This mechanism was validated using a resistant mutant. SMURF1 inhibitor prevents BMPR2 degradation, restores BMP signalling and cell homeostasis in patients with PAH. SMURF1 inhibition reversed pathological changes in experimental PAH models.Conclusions These findings demonstrate that SMURF1 inhibition reverse PAH pathology by restoring BMP signaling. This establishes SMURF1 as a promising therapeutic target and provides structural insights for developing inhibitors against HECT and other glycine-hing proteins.",
  "authors": [
    {
      "affiliations": [
        "University of Sheffield, Sheffield, UK",
        "Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia"
      ],
      "name": "Sarah K Binmahfooz"
    },
    {
      "affiliations": [
        "University of Sheffield, Sheffield, UK",
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Alexander MK Rothman"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Amir Florentin"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Basel, Switzerland"
      ],
      "name": "Florence Zink"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Catherine Quigley"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Olivier Bonneau"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Basel, Switzerland"
      ],
      "name": "Rene Hemmig"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Amanda Hachey"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Tomas Rejtar"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Maulik Thaker"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Rishi Jain"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Shih-Min Huang"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Horsham, UK"
      ],
      "name": "Daniel Sutton"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Horsham, UK"
      ],
      "name": "Jan Roger"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Ji-Hu Zhang"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Basel, Switzerland"
      ],
      "name": "Sven Weiler"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Basel, Switzerland"
      ],
      "name": "Simona Cotesta"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Basel, Switzerland"
      ],
      "name": "Johannes Ottl"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Salil Srivastava"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Alina Kordonsky"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Reut Avishid"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Elon Yariv"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Ritu Rathi"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Oshrit Khvalevsky"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Thomas Troxler"
    },
    {
      "affiliations": [
        "Faculty of Biology, Technion—Israel Institute of Technology, Israel"
      ],
      "name": "Oded Kleifeld"
    },
    {
      "affiliations": [
        "Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge, UK"
      ],
      "name": "Nicholas W Morrell"
    },
    {
      "affiliations": [
        "Université Paris–Saclay, INSERM UMR_S 999 (HPPIT), Service de Pneumologie et Soins Intensifs Respiratoires, Hôpital Bicêtre (Assistance Publique Hôpitaux de Paris), Le Kremlin Bicêtre, France"
      ],
      "name": "Marc Humbert"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Horsham, UK"
      ],
      "name": "Matthew J Thomas"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Horsham, UK"
      ],
      "name": "Gabor Jarai"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Rohan EJ Beckwith"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Jennifer S Cobb"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Nichola Smith"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Basel, Switzerland"
      ],
      "name": "Nils Ostermann"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "John Tallarico"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "Duncan Shaw"
    },
    {
      "affiliations": [
        "Novartis BioMedical Research, Basel, Switzerland"
      ],
      "name": "Sabine Guth-Gundel"
    },
    {
      "affiliations": [
        "School of Neurobiology, Biochemistry and Biophysics, The Life Sciences Faculty, Tel Aviv University, Tel Aviv, Israel",
        "Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel"
      ],
      "name": "Gali Prag"
    },
    {
      "affiliations": [
        "Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA"
      ],
      "name": "David J Rowlands"
    }
  ],
  "title": "BS06 Structural insights into SMURF1 inhibitions and its therapeutic potential in pulmonary arterial hypertension",
  "uid": "d869d22d-6e07-523c-91cb-82c266a80966"
}