Thrombospondin-1/CD47 signaling modulates transmembrane cation conductance, survival, and deformability of human red blo
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(2020) 18:155
RESEARCH
Open Access
Thrombospondin-1/CD47 signaling modulates transmembrane cation conductance, survival, and deformability of human red blood cells Rosi Bissinger1, Polina Petkova-Kirova2, Olga Mykhailova3,4, Per-Arne Oldenborg5, Elena Novikova5, David A. Donkor6,7, Thomas Dietz8, Abdulla Al Mamun Bhuyan9, William P. Sheffield6,7, Marijke Grau8, Ferruh Artunc1,10,11, Lars Kaestner12,13, Jason P. Acker3,4 and Syed M. Qadri6,7,14*
Abstract Background: Thrombospondin-1 (TSP-1), a Ca2+-binding trimeric glycoprotein secreted by multiple cell types, has been implicated in the pathophysiology of several clinical conditions. Signaling involving TSP-1, through its cognate receptor CD47, orchestrates a wide array of cellular functions including cytoskeletal organization, migration, cell-cell interaction, cell proliferation, autophagy, and apoptosis. In the present study, we investigated the impact of TSP-1/ CD47 signaling on Ca2+ dynamics, survival, and deformability of human red blood cells (RBCs). Methods: Whole-cell patch-clamp was employed to examine transmembrane cation conductance. RBC intracellular Ca2+ levels and multiple indices of RBC cell death were determined using cytofluorometry analysis. RBC morphology and microvesiculation were examined using imaging flow cytometry. RBC deformability was measured using laser-assisted optical rotational cell analyzer. Results: Exposure of RBCs to recombinant human TSP-1 significantly increased RBC intracellular Ca2+ levels. As judged by electrophysiology experiments, TSP-1 treatment elicited an amiloride-sensitive inward current alluding to a possible Ca2+ influx via non-selective cation channels. Exogenous TSP-1 promoted microparticle shedding as well as enhancing Ca2+- and nitric oxide-mediated RBC cell death. Monoclonal (mouse IgG1) antibody-mediated CD47 ligation using 1F7 recapitulated the cell death-inducing effects of TSP-1. Furthermore, TSP-1 treatment altered RBC cell shape and stiffness (maximum elongation index). Conclusions: Taken together, our data unravel a new role for TSP-1/CD47 signaling in mediating Ca2+ influx into RBCs, a mechanism potentially contributing to their dysfunction in a variety of systemic diseases. Keywords: Thrombospondin-1, CD47, Red blood cells, Calcium, Cation channels, Deformability
* Correspondence: [email protected] 14 Faculty of Health Sciences, Ontario Tech University, Oshawa, ON, Canada Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If
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