ITAM receptor-mediated generation of reactive oxygen species in human platelets occurs via Syk-dependent and Syk-independent pathways.
J Thromb Haemost
; 10(6): 1133-41, 2012 Jun.
Article
em En
| MEDLINE
| ID: mdl-22489915
ABSTRACT
BACKGROUND:
Ligation of the platelet-specific collagen receptor, GPVI/FcRγ, causes rapid, transient disulfide-dependent homodimerization, and the production of intracellular reactive oxygen species (ROS) generated by the NADPH oxidase, linked to GPVI via TRAF4.OBJECTIVES:
The aim of this study was to evaluate the role of early signaling events in ROS generation following engagement of either GPVI/FcRγ or a second immunoreceptor tyrosine-based activation motif (ITAM)-containing receptor on platelets, FcγRIIa. METHODS ANDRESULTS:
Using an H(2) DCF-DA-based flow cytometric assay to measure intracellular ROS, we show that treatment of platelets with either the GPVI agonists, collagen-related peptide (CRP) or convulxin (Cvx), or the FcγRIIa agonist 14A2, increased intraplatelet ROS; other platelet agonists such as ADP and TRAP did not. Basal ROS in platelet-rich plasma from 14 healthy donors displayed little inter-individual variability. CRP, Cvx or 14A2 induced an initial burst of ROS within 2 min followed by additional ROS reaching a plateau after 15-20 min. The Syk inhibitor BAY61-3606, which blocks ITAM-dependent signaling, had no effect on the initial ROS burst, but completely inhibited the second phase.CONCLUSIONS:
Together, these results show for the first time that ROS generation downstream of GPVI or FcγRIIa consists of two distinct phases an initial Syk-independent burst followed by additional Syk-dependent generation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plaquetas
/
Proteínas Tirosina Quinases
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Glicoproteínas da Membrana de Plaquetas
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Transdução de Sinais
/
Receptores de IgG
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Espécies Reativas de Oxigênio
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Peptídeos e Proteínas de Sinalização Intracelular
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
J Thromb Haemost
Ano de publicação:
2012
Tipo de documento:
Article