α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.

<h4>Objective</h4>Platelets express the α2β1 integrin and the glycoprotein VI (GPVI)/FcRγ complex, both collagen receptors. Understanding platelet-collagen receptor function has been enhanced through use of genetically modified mouse models. Previous studies of GPVI/FcRγ-mediated collage...

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Main Authors: Robin J Marjoram, Zhengzhi Li, Li He, Douglas M Tollefsen, Thomas J Kunicki, S Kent Dickeson, Samuel A Santoro, Mary M Zutter
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0114035&type=printable
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author Robin J Marjoram
Zhengzhi Li
Li He
Douglas M Tollefsen
Thomas J Kunicki
S Kent Dickeson
Samuel A Santoro
Mary M Zutter
author_facet Robin J Marjoram
Zhengzhi Li
Li He
Douglas M Tollefsen
Thomas J Kunicki
S Kent Dickeson
Samuel A Santoro
Mary M Zutter
author_sort Robin J Marjoram
collection DOAJ
description <h4>Objective</h4>Platelets express the α2β1 integrin and the glycoprotein VI (GPVI)/FcRγ complex, both collagen receptors. Understanding platelet-collagen receptor function has been enhanced through use of genetically modified mouse models. Previous studies of GPVI/FcRγ-mediated collagen-induced platelet activation were perfomed with mice in which the FcRγ subunit was genetically deleted (FcRγ-/-) or the complex was depleted. The development of α2β1-/- and GPVI-/- mice permits side-by-side comparison to address contributions of these collagen receptors in vivo and in vitro.<h4>Approach and results</h4>To understand the different roles played by the α2β1 integrin, the GPVI receptor or FcRγ subunit in collagen-stimulated hemostasis and thrombosis, we compared α2β1-/-, FcRγ-/-, and GPVI-/- mice in models of endothelial injury and intravascular thrombosis in vivo and their platelets in collagen-stimulated activation in vitro. We demonstrate that both the α2β1 integrin and the GPVI receptor, but not the FcRγ subunit influence carotid artery occlusion in vivo. In contrast, the GPVI receptor and the FcRγ chain, but not the α2β1 integrin, play similar roles in intravascular thrombosis in response to soluble Type I collagen. FcRγ-/- platelets showed less attenuation of tyrosine phosphorylation of several proteins including RhoGDI when compared to GPVI-/- and wild type platelets. The difference between FcRγ-/- and GPVI-/- platelet phosphotyrosine levels correlated with the in vivo thrombosis findings.<h4>Conclusion</h4>Our data demonstrate that genetic deletion of GPVI receptor, FcRγ chain, or the α2β1 integrin changes the thrombotic potentials of these platelets to collagen dependent on the stimulus mechanism. The data suggest that the FcRγ chain may provide a dominant negative effect through modulating signaling pathways in platelets involving several tyrosine phosphorylated proteins such as RhoGDI. In addition, these findings suggest a more complex signaling network downstream of the platelet collagen receptors than previously appreciated.
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spelling doaj-art-a0186060a2c64848bb49810c27afac212025-08-20T02:14:50ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-01911e11403510.1371/journal.pone.0114035α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.Robin J MarjoramZhengzhi LiLi HeDouglas M TollefsenThomas J KunickiS Kent DickesonSamuel A SantoroMary M Zutter<h4>Objective</h4>Platelets express the α2β1 integrin and the glycoprotein VI (GPVI)/FcRγ complex, both collagen receptors. Understanding platelet-collagen receptor function has been enhanced through use of genetically modified mouse models. Previous studies of GPVI/FcRγ-mediated collagen-induced platelet activation were perfomed with mice in which the FcRγ subunit was genetically deleted (FcRγ-/-) or the complex was depleted. The development of α2β1-/- and GPVI-/- mice permits side-by-side comparison to address contributions of these collagen receptors in vivo and in vitro.<h4>Approach and results</h4>To understand the different roles played by the α2β1 integrin, the GPVI receptor or FcRγ subunit in collagen-stimulated hemostasis and thrombosis, we compared α2β1-/-, FcRγ-/-, and GPVI-/- mice in models of endothelial injury and intravascular thrombosis in vivo and their platelets in collagen-stimulated activation in vitro. We demonstrate that both the α2β1 integrin and the GPVI receptor, but not the FcRγ subunit influence carotid artery occlusion in vivo. In contrast, the GPVI receptor and the FcRγ chain, but not the α2β1 integrin, play similar roles in intravascular thrombosis in response to soluble Type I collagen. FcRγ-/- platelets showed less attenuation of tyrosine phosphorylation of several proteins including RhoGDI when compared to GPVI-/- and wild type platelets. The difference between FcRγ-/- and GPVI-/- platelet phosphotyrosine levels correlated with the in vivo thrombosis findings.<h4>Conclusion</h4>Our data demonstrate that genetic deletion of GPVI receptor, FcRγ chain, or the α2β1 integrin changes the thrombotic potentials of these platelets to collagen dependent on the stimulus mechanism. The data suggest that the FcRγ chain may provide a dominant negative effect through modulating signaling pathways in platelets involving several tyrosine phosphorylated proteins such as RhoGDI. In addition, these findings suggest a more complex signaling network downstream of the platelet collagen receptors than previously appreciated.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0114035&type=printable
spellingShingle Robin J Marjoram
Zhengzhi Li
Li He
Douglas M Tollefsen
Thomas J Kunicki
S Kent Dickeson
Samuel A Santoro
Mary M Zutter
α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.
PLoS ONE
title α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.
title_full α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.
title_fullStr α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.
title_full_unstemmed α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.
title_short α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis.
title_sort α2β1 integrin gpvi receptor and common fcrγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0114035&type=printable
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