Summary
Platelets arrest bleeding by adhering to and aggregating on the subendothelium exposed
at the site of vessel injury.This process is initiated by the interaction between
the subendothelium von Willebrand factor (VWF) and the glycoprotein (GP) Ib-IX-V complex
on platelets.However,the same interaction also results in thrombosis at the site of
a ruptured atherosclerotic plaque. Reagents regulating the GP Ib-VWF interaction will
therefore have direct impact on haemostasis and thrombosis. We have characterised
an oligonucleotide G-quartet (T30923) that specifically blocks VWF binding to GP Ibα,
theVWF-binding subunit of the GP Ib-IX-V complex.We evaluated the potential interactions
of T30923 with GP Ibα and VWF A1 domain by computer simulated molecular dockings,
which identified four T30923 docking sites in the β-sheets of the N-terminal region
of GP Ibα (E14-D18, S39, D63-S64, and D83-S85). Experimentally,T30923 bound GP Ibα
and dose-dependently blocked platelet aggregation induced by ristocetin and thrombin,
but not by botrocetin, collagen, TRAP, and ADP. It also blocked shear-induced platelet
aggregation and thrombus formation on immobilized VWF under arterial shear stress.
These results demonstrate that T30923 may have therapeutic potentials to regulate
the GP IbαVWF interaction.
Keywords
Oligonucleotide - G-quartet - platelet - GP Ib - von Willebrand factor - shear stress