Page 214 - 2019_09-HaematologicaMondo-web

Ferrata Storti Foundation
Hemostasis
Tspan18 is a novel regulator of the Ca2+ channel Orai1 and von Willebrand factor release in endothelial cells
Haematologica 2019 Volume 104(9):1892-1905
Joseph Robinson,5 Chek Z. Koo,1 Alessandro Di Maio,1 Paul Harrison,6,7 Steven P. Lee,5 Francesco Michelangeli,8 Neena Kalia,2,9 G. Ed Rainger,2
Peter J. Noy,1 Rebecca L. Gavin,1 Dario Colombo,2 Elizabeth J. Haining,2 Jasmeet S. Reyat,1 Holly Payne,2 Ina Thielmann,3 Adam B. Lokman,2 Georgiana Neag,2 Jing Yang,1 Tammy Lloyd,1 Neale Harrison,1
Victoria L. Heath,2 Chris Gardiner,4 Katharine M. Whitworth,5
3 2,9,10 2,9 Bernhard Nieswandt, Alexander Brill, Steve P. Watson
and
Michael G. Tomlinson1,9
1School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK; 2Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK; 3University Hospital Würzburg and Rudolf Virchow Center for Experimental Biomedicine, Würzburg, Germany; 4Department of Haematology, University College London, London, UK; 5Institute of Immunology and Immunotherapy, Cancer Immunology and Immunotherapy Centre, University of Birmingham, Birmingham, UK; 6Scar Free Foundation for Burns Research, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham National Health Service (NHS) Foundation Trust, Birmingham, UK; 7Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK; 8Department of Biological Sciences, University of Chester, Chester, UK; 9Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham- Nottingham, UK and 10Department of Pathophysiology, Sechenov First Moscow State Medical University, Moscow, Russia
ABSTRACT
Ca2+ entry via Orai1 store-operated Ca2+ channels in the plasma membrane is critical to cell function, and Orai1 loss causes severe immunodeficiency and developmental defects. The tetraspanins are a superfamily of transmembrane proteins that interact with specific ‘partner proteins’ and regulate their trafficking and clustering. The aim of this study was to functionally characterize tetraspanin Tspan18. We show that Tspan18 is expressed by endothelial cells at several-fold high- er levels than most other cell types analyzed. Tspan18-knockdown pri- mary human umbilical vein endothelial cells have 55-70% decreased Ca2+ mobilization upon stimulation with the inflammatory mediators thrombin or histamine, similar to Orai1-knockdown. Tspan18 interacts with Orai1, and Orai1 cell surface localization is reduced by 70% in Tspan18-knockdown endothelial cells. Tspan18 overexpression in lym- phocyte model cell lines induces 20-fold activation of Ca2+ -responsive nuclear factor of activated T cell (NFAT) signaling, in an Orai1-dependent manner. Tspan18-knockout mice are viable. They lose on average 6-fold more blood in a tail-bleed assay. This is due to Tspan18 deficiency in non-hematopoietic cells, as assessed using chimeric mice. Tspan18- knockout mice have 60% reduced thrombus size in a deep vein throm- bosis model, and 50% reduced platelet deposition in the microcircula- tion following myocardial ischemia-reperfusion injury. Histamine- or thrombin-induced von Willebrand factor release from endothelial cells is reduced by 90% following Tspan18-knockdown, and histamine-induced increase of plasma von Willebrand factor is reduced by 45% in Tspan18- knockout mice. These findings identify Tspan18 as a novel regulator of endothelial cell Orai1/Ca2+ signaling and von Willebrand factor release in response to inflammatory stimuli.
Correspondence:
MICHAEL G. TOMLINSON
m.g.tomlinson@bham.ac.uk
Received: March 26, 2018. Accepted: December 19, 2018. Pre-published: December 20, 2018.
doi:10.3324/haematol.2018.194241
Check the online version for the most updated information on this article, online supplements, and information on authorship & disclosures: www.haematologica.org/content/104/9/1892
©2019 Ferrata Storti Foundation
Material published in Haematologica is covered by copyright. All rights are reserved to the Ferrata Storti Foundation. Use of published material is allowed under the following terms and conditions: https://creativecommons.org/licenses/by-nc/4.0/legalcode. Copies of published material are allowed for personal or inter- nal use. Sharing published material for non-commercial pur- poses is subject to the following conditions: https://creativecommons.org/licenses/by-nc/4.0/legalcode, sect. 3. Reproducing and sharing published material for com- mercial purposes is not allowed without permission in writing from the publisher.
1892
haematologica | 2019; 104(9)
ARTICLE