Platelet activation induces metalloproteinase-dependent GP VI cleavage to down-regulate platelet reactivity to collagen

Stephens, G; Yan, Y; Jandrot-Perrus, M; Villeval, JL; Clemetson, KJ; Phillips, DR (2005). Platelet activation induces metalloproteinase-dependent GP VI cleavage to down-regulate platelet reactivity to collagen. Blood, 105(1), pp. 186-91. Washington, D.C.: American Society of Hematology 10.1182/blood-2004-07-2842

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Glycoprotein (GP) VI, the primary collagen receptor on platelets, has been shown to have variable expression, possibly as a consequence of immune modulation. The present study was designed to determine the mechanism by which GP VI clearance occurs. We found that direct activation of GP VI both by a GP VI-specific antibody and by GP VI ligands (collagen and convulxin) reduced binding of biotinylated convulxin to the stimulated platelets. Analysis of immunoblots of platelets and supernatants showed that the stimulated platelets contained less GP VI, while the soluble fraction contained a 57-kDa cleavage product. Stimulation of platelets with PAR-1 agonists (TRAP peptide and thrombin) also caused GP VI cleavage, although the amount of GP VI loss was less than that observed with direct GP VI ligands. The metalloproteinase (MMP) inhibitors GM6001 and TAPI prevented both the clearance of GP VI from the platelet surface and the appearance of the soluble cleavage product. Induction of GP VI cleavage caused specific down-regulation of collagen-induced platelet aggregation, providing a mechanism for the modulation of platelet responsiveness to this important platelet agonist.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Theodor Kocher Institute

UniBE Contributor:

Clemetson, Kenneth John

ISSN:

0006-4971

ISBN:

15339851

Publisher:

American Society of Hematology

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:52

Last Modified:

04 May 2014 23:15

Publisher DOI:

10.1182/blood-2004-07-2842

PubMed ID:

15339851

Web of Science ID:

000225997100035

URI:

https://boris.unibe.ch/id/eprint/22159 (FactScience: 32154)

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