Involvement of Ca2+ Activated Cl- Channel Ano6 in Platelet Activation and Apoptosis

Liu, Guoxing and Liu, Guilai and Chen, Hong and Borst, Oliver and Gawaz, Meinrad and Vortkamp, Andrea and Schreiber, Rainer and Kunzelmann, Karl and Lang, Florian (2015) Involvement of Ca2+ Activated Cl- Channel Ano6 in Platelet Activation and Apoptosis. CELLULAR PHYSIOLOGY AND BIOCHEMISTRY, 37 (5). pp. 1934-1944. ISSN 1015-8987, 1421-9778

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Abstract

Background/Aims: The ubiquitously expressed Ca2+ Activated Cl-Channel Ano6 participates in the stimulation of cell membrane scrambling. Defective Ano6 underlies the Scott syndrome, an inherited bleeding disorder with impaired scrambling of plasma membrane phospholipids. At least in theory, the bleeding disorder of Scott syndrome may result from impaired platelet function. Activators of platelets include thrombin and collagen related peptide (CRP), which trigger increase of cytosolic Ca2+-activity ([Ca2+](i)), production of reactive oxygen species (ROS), degranulation, integrin activation, as well as cell shrinkage and phospholipid scrambling of the cell membrane. The present study thus explored whether Ano6 modifies activation-induced alterations of cytosolic Ca2+-activity ([Ca2+](i)), degranulation (P-selectin exposure), integrin activation, phosphatidylserine exposure on the platelet surface and platelet volume. Methods: Platelets from mice lacking Ano6 (ano6(-/-)) were compared to platelets from corresponding wild-type mice (ano6(+/+)). [Ca2+](i) was estimated from Fluo-3 fluorescence, ROS from DCFDA fluorescence, degranulation from P-selectin abundance, integrin activation from alpha(IIb)beta(3)-integrin abundance, phosphatidylserine abundance from annexin-V-binding, and cell volume from forward scatter. Results: Platelet number in blood was slightly higher in ano6(-/-) mice than in ano6(+/+) mice. Without activation [Ca2+](i) and volume were similar in ano6(-/-) and ano6(+/+) platelets as well as ROS abundance, P-selectin abundance, alpha(IIb)beta(3) integrin activation, and phosphatidylserine exposure were negligible in both genotypes. Thrombin (0.01 U/ml) and CRP (2 or 5 mu g/ml) increased [Ca2+](i), ROS abundance, platelet degranulation, alpha(IIb)beta(3) integrin activation, and triggered annexin-V-binding as well as cell shrinkage, all effects less pronounced in ano6(-/-) than in ano6(+/+) platelets. Conclusions: Genetic knockout of Ano6 blunts thrombin-and CRP-induced activation and apoptosis of blood platelets. (C) 2015 The Author(s) Published by S. Karger AG, Basel

Item Type: Article
Uncontrolled Keywords: SCRAMBLASE ACTIVITY; EXPRESSION; KINASE; STIM; ORAI; Cytosolic Ca2+ concentration; Phosphatidylserine translocation; P-selectin; Integrin; Cell-volume
Subjects: 600 Technology > 610 Medical sciences Medicine
Divisions: Biology, Preclinical Medicine > Institut für Physiologie
Depositing User: Dr. Gernot Deinzer
Date Deposited: 26 Jul 2019 09:30
Last Modified: 26 Jul 2019 09:30
URI: https://pred.uni-regensburg.de/id/eprint/6145

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