Shear stress-induced binding of von Willebrand factor to platelets

K. Konstantopoulos, T. W. Chow, N. A. Turner, J. D. Hellums, J. L. Moake

Research output: Contribution to journalArticle

Abstract

Shear stress-induced platelet aggregation requires von Willebrand factor (vWF), platelet glycoprotein (GP)Ib, GPIIb-IIIa, Ca2+, and adenosine diphosphate (ADP). Recent reports using vWF labeled with either 125I or fluorescein isothiocyanate (FITC) have demonstrated that in shear-fields, vWF binds to both GPIb and GPIIb-IIIa. The sequence of the vWF binding to the two platelet receptors has not been precisely determined in these reports. In this study, a flow cytometry technique using a primary anti-vWF antibody and a secondary FITC IgG antibody was used to measure shear stress-induced vWF binding to platelets. Washed normal platelet suspended at 50,000/μl with purified large vWF multimers were exposed to laminar shear stresses of 15 to 120 dynes/cm2 for 30 sec. At this low platelet count, little or no aggregation occurred in the shear fields. A significant increase in post-shear vWF-positive platelets was consistently observed. Experiment with platelets from normal and severe von Willebrand's disease (vWD) (which lack plasma and platelet α-granule vWF) demonstrated that exogenous vWF predominately contributed to the platelet-vWF binding. Blockade of platelet GPIb with the monoclonal anti-GPIb antibody, 6D1, completely inhibited shear stress-induced platelet-vWF attachment. In contrast, blockade of GPIIb-IIIa with monoclonal anti-GPIIb-IIIa antibodies, 10E5 or c7E3, or with the GPIIb-IIIa-blocking tetrapeptide, RGDS, had little or no inhibitory effect on platelet-vWF binding. These data demonstrate that the binding of vWF to GPIb is likely to be the initial shear-induced platelet-ligand binding event.

Original languageEnglish (US)
Pages (from-to)57-71
Number of pages15
JournalBiorheology
Volume34
Issue number1
DOIs
StatePublished - Jun 6 1997
Externally publishedYes

Keywords

  • GPIIb-IIIa
  • glycoprotein (GP)Ib
  • shear stress
  • von Willebrand factor

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Shear stress-induced binding of von Willebrand factor to platelets'. Together they form a unique fingerprint.

  • Cite this