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Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses

Background  Zinc (Zn (2+) ) is an essential trace element that regulates intracellular processes in multiple cell types. While the role of Zn (2+) as a platelet agonist is known, its secondary messenger activity in platelets has not been demonstrated. Objectives  This article determines whether cyto...

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Autores principales: Ahmed, Niaz S., Lopes Pires, Maria E., Taylor, Kirk A., Pugh, Nicholas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Georg Thieme Verlag KG 2019
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327715/
https://www.ncbi.nlm.nih.gov/pubmed/30597507
http://dx.doi.org/10.1055/s-0038-1676589
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author Ahmed, Niaz S.
Lopes Pires, Maria E.
Taylor, Kirk A.
Pugh, Nicholas
author_facet Ahmed, Niaz S.
Lopes Pires, Maria E.
Taylor, Kirk A.
Pugh, Nicholas
author_sort Ahmed, Niaz S.
collection PubMed
description Background  Zinc (Zn (2+) ) is an essential trace element that regulates intracellular processes in multiple cell types. While the role of Zn (2+) as a platelet agonist is known, its secondary messenger activity in platelets has not been demonstrated. Objectives  This article determines whether cytosolic Zn (2+) concentrations ([Zn (2+) ] (i) ) change in platelets in response to agonist stimulation, in a manner consistent with a secondary messenger, and correlates the effects of [Zn (2+) ] (i) changes on activation markers. Methods  Changes in [Zn (2+) ] (i) were quantified in Fluozin-3 (Fz-3)-loaded washed, human platelets using fluorometry. Increases in [Zn (2+) ] (i) were modelled using Zn (2+) -specific chelators and ionophores. The influence of [Zn (2+) ] (i) on platelet function was assessed using platelet aggregometry, flow cytometry and Western blotting. Results  Increases of intra-platelet Fluozin-3 (Fz-3) fluorescence occurred in response to stimulation by cross-linked collagen-related peptide (CRP-XL) or U46619, consistent with a rise of [Zn (2+) ] (i) . Fluoresence increases were blocked by Zn (2+) chelators and modulators of the platelet redox state, and were distinct from agonist-evoked [Ca (2+) ] (i) signals. Stimulation of platelets with the Zn (2+) ionophores clioquinol (Cq) or pyrithione (Py) caused sustained increases of [Zn (2+) ] (i) , resulting in myosin light chain phosphorylation, and cytoskeletal re-arrangements which were sensitive to cytochalasin-D treatment. Cq stimulation resulted in integrin α (IIb) β (3) activation and release of dense, but not α, granules. Furthermore, Zn (2+) -ionophores induced externalization of phosphatidylserine. Conclusion  These data suggest that agonist-evoked fluctuations in intra-platelet Zn (2+) couple to functional responses, in a manner that is consistent with a role as a secondary messenger. Increased intra-platelet Zn (2+) regulates signalling processes, including shape change, α (IIb) β (3) up-regulation and dense granule release, in a redox-sensitive manner.
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spelling pubmed-63277152019-01-13 Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses Ahmed, Niaz S. Lopes Pires, Maria E. Taylor, Kirk A. Pugh, Nicholas Thromb Haemost Background  Zinc (Zn (2+) ) is an essential trace element that regulates intracellular processes in multiple cell types. While the role of Zn (2+) as a platelet agonist is known, its secondary messenger activity in platelets has not been demonstrated. Objectives  This article determines whether cytosolic Zn (2+) concentrations ([Zn (2+) ] (i) ) change in platelets in response to agonist stimulation, in a manner consistent with a secondary messenger, and correlates the effects of [Zn (2+) ] (i) changes on activation markers. Methods  Changes in [Zn (2+) ] (i) were quantified in Fluozin-3 (Fz-3)-loaded washed, human platelets using fluorometry. Increases in [Zn (2+) ] (i) were modelled using Zn (2+) -specific chelators and ionophores. The influence of [Zn (2+) ] (i) on platelet function was assessed using platelet aggregometry, flow cytometry and Western blotting. Results  Increases of intra-platelet Fluozin-3 (Fz-3) fluorescence occurred in response to stimulation by cross-linked collagen-related peptide (CRP-XL) or U46619, consistent with a rise of [Zn (2+) ] (i) . Fluoresence increases were blocked by Zn (2+) chelators and modulators of the platelet redox state, and were distinct from agonist-evoked [Ca (2+) ] (i) signals. Stimulation of platelets with the Zn (2+) ionophores clioquinol (Cq) or pyrithione (Py) caused sustained increases of [Zn (2+) ] (i) , resulting in myosin light chain phosphorylation, and cytoskeletal re-arrangements which were sensitive to cytochalasin-D treatment. Cq stimulation resulted in integrin α (IIb) β (3) activation and release of dense, but not α, granules. Furthermore, Zn (2+) -ionophores induced externalization of phosphatidylserine. Conclusion  These data suggest that agonist-evoked fluctuations in intra-platelet Zn (2+) couple to functional responses, in a manner that is consistent with a role as a secondary messenger. Increased intra-platelet Zn (2+) regulates signalling processes, including shape change, α (IIb) β (3) up-regulation and dense granule release, in a redox-sensitive manner. Georg Thieme Verlag KG 2019-01 2018-12-31 /pmc/articles/PMC6327715/ /pubmed/30597507 http://dx.doi.org/10.1055/s-0038-1676589 Text en https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Ahmed, Niaz S.
Lopes Pires, Maria E.
Taylor, Kirk A.
Pugh, Nicholas
Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses
title Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses
title_full Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses
title_fullStr Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses
title_full_unstemmed Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses
title_short Agonist-Evoked Increases in Intra-Platelet Zinc Couple to Functional Responses
title_sort agonist-evoked increases in intra-platelet zinc couple to functional responses
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327715/
https://www.ncbi.nlm.nih.gov/pubmed/30597507
http://dx.doi.org/10.1055/s-0038-1676589
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