Platelet glycoprotein VI cluster size is related to thrombus formation and phosphatidylserine exposure in collagen-adherent platelets under arterial shear.
glycoprotein VI
nanobody
platelet activation
receptor clustering
thrombus formation
Journal
Journal of thrombosis and haemostasis : JTH
ISSN: 1538-7836
Titre abrégé: J Thromb Haemost
Pays: England
ID NLM: 101170508
Informations de publication
Date de publication:
08 2023
08 2023
Historique:
received:
11
10
2022
revised:
30
03
2023
accepted:
17
04
2023
medline:
21
7
2023
pubmed:
8
5
2023
entrez:
7
5
2023
Statut:
ppublish
Résumé
Collagen-induced platelet activation is predominantly mediated by glycoprotein (GP) VI through formation of receptor clusters that coincide with the accumulation of signaling molecules and are hypothesized to drive strong and sustained platelet activation. To determine the importance of GPVI clusters for thrombus formation in whole blood under shear. We utilized whole blood microfluidics and an anti-GPVI nanobody (Nb), Nb28, labeled with AlexaFluor 488, to assess the distribution of GPVI on the surface of platelets adhering to a range of collagen-like substrates with different platelet activation potentials. Automated analysis of GPVI surface distribution on platelets supported the hypothesis that there is a relationship between GPVI cluster formation, thrombus size, and phosphatidylserine (PS) exposure. Substrates that supported the formation of macroclusters also induced significantly bigger aggregates, with increased amounts of PS-exposing platelets in comparison to substrates where no GPVI clusters were detected. Furthermore, we demonstrate that only direct inhibition of GPVI binding, but not of downstream signaling, is able to disrupt cluster formation. Labeled anti-GPVI Nb28 permits visualization of GPVI clustering under flow conditions. Furthermore, whilst inhibition of downstream signaling does not affect clustering, it does prevent thrombus formation. Therefore, GPVI macroclustering is a prerequisite for thrombus formation and platelet activation, namely, PS exposure, on highly GPVI-dependent collagen surfaces.
Sections du résumé
BACKGROUND
Collagen-induced platelet activation is predominantly mediated by glycoprotein (GP) VI through formation of receptor clusters that coincide with the accumulation of signaling molecules and are hypothesized to drive strong and sustained platelet activation.
OBJECTIVES
To determine the importance of GPVI clusters for thrombus formation in whole blood under shear.
METHODS
We utilized whole blood microfluidics and an anti-GPVI nanobody (Nb), Nb28, labeled with AlexaFluor 488, to assess the distribution of GPVI on the surface of platelets adhering to a range of collagen-like substrates with different platelet activation potentials.
RESULTS
Automated analysis of GPVI surface distribution on platelets supported the hypothesis that there is a relationship between GPVI cluster formation, thrombus size, and phosphatidylserine (PS) exposure. Substrates that supported the formation of macroclusters also induced significantly bigger aggregates, with increased amounts of PS-exposing platelets in comparison to substrates where no GPVI clusters were detected. Furthermore, we demonstrate that only direct inhibition of GPVI binding, but not of downstream signaling, is able to disrupt cluster formation.
CONCLUSION
Labeled anti-GPVI Nb28 permits visualization of GPVI clustering under flow conditions. Furthermore, whilst inhibition of downstream signaling does not affect clustering, it does prevent thrombus formation. Therefore, GPVI macroclustering is a prerequisite for thrombus formation and platelet activation, namely, PS exposure, on highly GPVI-dependent collagen surfaces.
Identifiants
pubmed: 37150294
pii: S1538-7836(23)00350-1
doi: 10.1016/j.jtha.2023.04.028
pii:
doi:
Substances chimiques
platelet membrane glycoprotein VI
0
Phosphatidylserines
0
Platelet Membrane Glycoproteins
0
Collagen
9007-34-5
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
2260-2267Subventions
Organisme : British Heart Foundation
ID : CH 03/003
Pays : United Kingdom
Informations de copyright
Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of competing interests S.P.W. and N.S.P. have a patent for the anti-GPVI nanobodies (WO2022/136457). R.W.F. is the Chief Scientific Officer of CambCol Laboratories Ltd. The other authors have no competing interests to disclose.