Staphylococcal superantigen-like 5 activates platelets and supports platelet adhesion under flow conditions, which involves glycoprotein Ibalpha and alpha IIb beta 3.
J Thromb Haemost
; 7(11): 1867-74, 2009 Nov.
Article
in En
| MEDLINE
| ID: mdl-19656281
ABSTRACT
OBJECTIVES:
Staphylococcal superantigen-like 5 (SSL5) is an exoprotein secreted by Staphylococcus aureus that has been shown to inhibit neutrophil rolling over activated endothelial cells via a direct interaction with P-selectin glycoprotein ligand 1 (PSGL-1). METHODS ANDRESULTS:
When purified recombinant SSL5 was added to washed platelets in an aggregometry set-up, complete and irreversible aggregation was observed. Proteolysis of the extracellular part of GPIb alpha or the addition of dRGDW abrogated platelet aggregation. When a mixture of isolated platelets and red cells was perfused over immobilized SSL5 at a shear rate of 300 s(-1), stable platelet aggregates were observed, and platelet deposition was substantially reduced after proteolysis of GPIb or after addition of dRGDW. SSL5 was shown to interact with glycocalicin, a soluble GPIb alpha fragment, and binding of SSL5 to platelets resulted in GPIb-mediated signal transduction as evidenced by translocation of 14-3-3 zeta. In addition, SSL5 was shown to interact with endothelial cell matrix (ECM) and this interaction enhanced aggregation of platelets from whole blood to this ECM.CONCLUSIONS:
SSL5 activates and aggregates platelets in a GPIb alpha-dependent manner, which could be important in colonization of the vascular bed and evasion of the immune system by S. aureus.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Staphylococcus
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Blood Platelets
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Platelet Activation
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Platelet Adhesiveness
/
Superantigens
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Platelet Glycoprotein GPIIb-IIIa Complex
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Platelet Glycoprotein GPIb-IX Complex
Language:
En
Journal:
J Thromb Haemost
Journal subject:
HEMATOLOGIA
Year:
2009
Document type:
Article
Affiliation country: