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Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque

BACKGROUND: Platelet activation requires rapid remodeling of the actin cytoskeleton which is regulated by small GTP-binding proteins. By using the Rac1-specific inhibitor NSC23766, we have recently found that Rac1 is a central component of a signaling pathway that regulates dephosphorylation and act...

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Autores principales: Dwivedi, Suman, Pandey, Dharmendra, Khandoga, Anna L, Brandl, Richard, Siess, Wolfgang
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018435/
https://www.ncbi.nlm.nih.gov/pubmed/21134286
http://dx.doi.org/10.1186/1479-5876-8-128
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author Dwivedi, Suman
Pandey, Dharmendra
Khandoga, Anna L
Brandl, Richard
Siess, Wolfgang
author_facet Dwivedi, Suman
Pandey, Dharmendra
Khandoga, Anna L
Brandl, Richard
Siess, Wolfgang
author_sort Dwivedi, Suman
collection PubMed
description BACKGROUND: Platelet activation requires rapid remodeling of the actin cytoskeleton which is regulated by small GTP-binding proteins. By using the Rac1-specific inhibitor NSC23766, we have recently found that Rac1 is a central component of a signaling pathway that regulates dephosphorylation and activation of the actin-dynamising protein cofilin, dense and α-granule secretion, and subsequent aggregation of thrombin-stimulated washed platelets. OBJECTIVES: To study whether NSC23766 inhibits stimulus-induced platelet secretion and aggregation in blood. METHODS: Human platelet aggregation and ATP-secretion were measured in hirudin-anticoagulated blood and platelet-rich plasma (PRP) by using multiple electrode aggregometry and the Lumi-aggregometer. Platelet P-selectin expression was quantified by flow cytometry. RESULTS: NSC23766 (300 μM) inhibited TRAP-, collagen-, atherosclerotic plaque-, and ADP-induced platelet aggregation in blood by 95.1%, 93.4%, 92.6%, and 70%, respectively. The IC(50 )values for inhibition of TRAP-, collagen-, and atherosclerotic plaque-, were 50 ± 18 μM, 64 ± 35 μM, and 50 ± 30 μM NSC23766 (mean ± SD, n = 3-7), respectively. In blood containing RGDS to block integrin α(IIb)β(3)-mediated platelet aggregation, NSC23766 (300 μM) completely inhibited P-selectin expression and reduced ATP-secretion after TRAP and collagen stimulation by 73% and 85%, respectively. In ADP-stimulated PRP, NSC23766 almost completely inhibited P-selectin expression, in contrast to aspirin, which was ineffective. Moreover, NSC23766 (300 μM) decreased plaque-stimulated platelet adhesion/aggregate formation under arterial flow conditions (1500s(-1)) by 72%. CONCLUSIONS: Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in blood stimulated by a wide array of platelet agonists including atherosclerotic plaque. By specifically inhibiting platelet secretion, the pharmacological targeting of Rac1 could be an interesting approach in the development of future antiplatelet drugs.
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spelling pubmed-30184352011-01-11 Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque Dwivedi, Suman Pandey, Dharmendra Khandoga, Anna L Brandl, Richard Siess, Wolfgang J Transl Med Research BACKGROUND: Platelet activation requires rapid remodeling of the actin cytoskeleton which is regulated by small GTP-binding proteins. By using the Rac1-specific inhibitor NSC23766, we have recently found that Rac1 is a central component of a signaling pathway that regulates dephosphorylation and activation of the actin-dynamising protein cofilin, dense and α-granule secretion, and subsequent aggregation of thrombin-stimulated washed platelets. OBJECTIVES: To study whether NSC23766 inhibits stimulus-induced platelet secretion and aggregation in blood. METHODS: Human platelet aggregation and ATP-secretion were measured in hirudin-anticoagulated blood and platelet-rich plasma (PRP) by using multiple electrode aggregometry and the Lumi-aggregometer. Platelet P-selectin expression was quantified by flow cytometry. RESULTS: NSC23766 (300 μM) inhibited TRAP-, collagen-, atherosclerotic plaque-, and ADP-induced platelet aggregation in blood by 95.1%, 93.4%, 92.6%, and 70%, respectively. The IC(50 )values for inhibition of TRAP-, collagen-, and atherosclerotic plaque-, were 50 ± 18 μM, 64 ± 35 μM, and 50 ± 30 μM NSC23766 (mean ± SD, n = 3-7), respectively. In blood containing RGDS to block integrin α(IIb)β(3)-mediated platelet aggregation, NSC23766 (300 μM) completely inhibited P-selectin expression and reduced ATP-secretion after TRAP and collagen stimulation by 73% and 85%, respectively. In ADP-stimulated PRP, NSC23766 almost completely inhibited P-selectin expression, in contrast to aspirin, which was ineffective. Moreover, NSC23766 (300 μM) decreased plaque-stimulated platelet adhesion/aggregate formation under arterial flow conditions (1500s(-1)) by 72%. CONCLUSIONS: Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in blood stimulated by a wide array of platelet agonists including atherosclerotic plaque. By specifically inhibiting platelet secretion, the pharmacological targeting of Rac1 could be an interesting approach in the development of future antiplatelet drugs. BioMed Central 2010-12-06 /pmc/articles/PMC3018435/ /pubmed/21134286 http://dx.doi.org/10.1186/1479-5876-8-128 Text en Copyright ©2010 Dwivedi et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (<url>http://creativecommons.org/licenses/by/2.0</url>), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research
Dwivedi, Suman
Pandey, Dharmendra
Khandoga, Anna L
Brandl, Richard
Siess, Wolfgang
Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque
title Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque
title_full Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque
title_fullStr Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque
title_full_unstemmed Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque
title_short Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque
title_sort rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018435/
https://www.ncbi.nlm.nih.gov/pubmed/21134286
http://dx.doi.org/10.1186/1479-5876-8-128
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