The C-Type Lectin Receptor CD93 Regulates Platelet Activation and Surface Expression of the Protease Activated Receptor 4.
Journal
Thrombosis and haemostasis
ISSN: 2567-689X
Titre abrégé: Thromb Haemost
Pays: Germany
ID NLM: 7608063
Informations de publication
Date de publication:
30 Sep 2023
30 Sep 2023
Historique:
pubmed:
6
9
2023
medline:
6
9
2023
entrez:
5
9
2023
Statut:
aheadofprint
Résumé
The C-type lectin receptor CD93 is a single pass type I transmembrane glycoprotein involved in inflammation, immunity, and angiogenesis. This study investigates the role of CD93 in platelet function. CD93 knockout (KO) mice and wild-type (WT) controls were compared in this study. Platelet activation and aggregation were investigated by flow cytometry and light transmission aggregometry, respectively. Protein expression and phosphorylation were analyzed by immunoblotting. Subcellular localization of membrane receptors was investigated by wide-field and confocal microscopy. The lack of CD93 in mice was not associated to any evident bleeding defect and no alterations of platelet activation were observed upon stimulation with thromboxane A2 analogue and convulxin. Conversely, platelet aggregation induced by stimulation of the thrombin receptor PAR4 was significantly reduced in the absence of CD93. This defect was associated with a significant reduction of α-granule secretion, integrin αIIbβ3 activation, and protein kinase C (PKC) stimulation. Resting WT and CD93-deficient platelets expressed comparable amounts of PAR4. However, upon stimulation with a PAR4 activating peptide, a more pronounced clearance of PAR4 from the platelet surface was observed in CD93-deficient platelets compared with WT controls. Confocal microscopy analysis revealed a massive movement of PAR4 in cytosolic compartments of activated platelets lacking CD93. Accordingly, platelet desensitization following PAR4 stimulation was more pronounced in CD93 KO platelets compared with WT controls. These results demonstrate that CD93 supports platelet activation triggered by PAR4 stimulation and is required to stabilize the expression of the thrombin receptor on the cell surface.
Sections du résumé
BACKGROUND
BACKGROUND
The C-type lectin receptor CD93 is a single pass type I transmembrane glycoprotein involved in inflammation, immunity, and angiogenesis. This study investigates the role of CD93 in platelet function. CD93 knockout (KO) mice and wild-type (WT) controls were compared in this study.
METHODS
METHODS
Platelet activation and aggregation were investigated by flow cytometry and light transmission aggregometry, respectively. Protein expression and phosphorylation were analyzed by immunoblotting. Subcellular localization of membrane receptors was investigated by wide-field and confocal microscopy.
RESULTS
RESULTS
The lack of CD93 in mice was not associated to any evident bleeding defect and no alterations of platelet activation were observed upon stimulation with thromboxane A2 analogue and convulxin. Conversely, platelet aggregation induced by stimulation of the thrombin receptor PAR4 was significantly reduced in the absence of CD93. This defect was associated with a significant reduction of α-granule secretion, integrin αIIbβ3 activation, and protein kinase C (PKC) stimulation. Resting WT and CD93-deficient platelets expressed comparable amounts of PAR4. However, upon stimulation with a PAR4 activating peptide, a more pronounced clearance of PAR4 from the platelet surface was observed in CD93-deficient platelets compared with WT controls. Confocal microscopy analysis revealed a massive movement of PAR4 in cytosolic compartments of activated platelets lacking CD93. Accordingly, platelet desensitization following PAR4 stimulation was more pronounced in CD93 KO platelets compared with WT controls.
CONCLUSION
CONCLUSIONS
These results demonstrate that CD93 supports platelet activation triggered by PAR4 stimulation and is required to stabilize the expression of the thrombin receptor on the cell surface.
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Subventions
Organisme : Italian Ministry of Education, University and Research (MIUR)
ID : Dipartimenti di Eccellenza Program (2018-2022) -
Informations de copyright
Thieme. All rights reserved.
Déclaration de conflit d'intérêts
None declared.