Potent vasorelaxant activity of the TMEM16A inhibitor T16Ainh-A01

Authors

  • Alison J Davis,

    1. Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's, University of London, London, UK
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    • The authors Alison J Davis, Jian Shi and Harry AT Pritchard contributed equally.
  • Jian Shi,

    1. Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's, University of London, London, UK
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    • The authors Alison J Davis, Jian Shi and Harry AT Pritchard contributed equally.
  • Harry AT Pritchard,

    1. Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's, University of London, London, UK
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    • The authors Alison J Davis, Jian Shi and Harry AT Pritchard contributed equally.
  • Preet S Chadha,

    1. Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's, University of London, London, UK
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  • Normand Leblanc,

    1. Department of Pharmacology, University of Nevada, Reno, NV, USA
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  • Georgios Vasilikostas,

    1. Department of Surgery, St George's Hospital, London, UK
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  • Zhen Yao,

    1. Departments of Medicine and Physiology, University of California, San Francisco, CA, USA
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  • AS Verkman,

    1. Departments of Medicine and Physiology, University of California, San Francisco, CA, USA
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  • Anthony P Albert,

    1. Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's, University of London, London, UK
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  • Iain A Greenwood

    Corresponding author
    1. Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's, University of London, London, UK
    • Correspondence

      Iain Greenwood, Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's, University of London, London SW17 0RE, UK. E-mail: i.greenwood@sgul.ac.uk

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Abstract

Background and Purpose

T16Ainh-A01 is a recently identified inhibitor of the calcium-activated chloride channel TMEM16A. The aim of this study was to test the efficacy of T16Ainh-A01 for inhibition of calcium-activated chloride channels in vascular smooth muscle and consequent effects on vascular tone.

Experimental Approach

Single channel and whole cell patch clamp was performed on single smooth muscle cells from rabbit pulmonary artery and mouse thoracic aorta. Isometric tension studies were performed on mouse thoracic aorta and mesenteric artery as well as human abdominal visceral adipose artery.

Key Results

In rabbit pulmonary artery myocytes T16Ainh-A01 (1–30 μM) inhibited single calcium (Ca2+)-activated chloride (Cl) channels and whole cell currents activated by 500 nM free Ca2+. Similar effects were observed for single Ca2+-activated Cl channels in mouse thoracic aorta, and in both cell types, channel activity was abolished by two antisera raised against TMEM16A but not by a bestrophin antibody. The TMEM16A potentiator, Fact (10 μM), increased single channel and whole cell Ca2+-activated Cl currents in rabbit pulmonary arteries. In isometric tension studies, T16Ainh-A01 relaxed mouse thoracic aorta pre-contracted with methoxamine with an IC50 of 1.6 μM and suppressed the methoxamine concentration–effect curve. T16Ainh-A01 did not affect the maximal contraction produced by 60 mM KCl and the relaxant effect of 10 μM T16Ainh-A01 was not altered by incubation of mouse thoracic aorta in a cocktail of potassium (K+) channel blockers. T16Ainh-A01 (10 μM) also relaxed human visceral adipose arteries by 88 ± 3%.

Conclusions and Implications

T16Ainh-A01 blocks calcium-activated chloride channels in vascular smooth muscle cells and relaxes murine and human blood vessels.

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