Inhibition of von Willebrand factor-mediated platelet activation and thrombosis by the anti-von Willebrand factor A1-domain aptamer ARC1779.
BACKGROUND
von Willebrand factor (VWF) has a role in both hemostasis and thrombosis. Platelets adhere to damaged arteries by interactions between the VWF A1-domain and glycoprotein Ib receptors under conditions of high shear. This initial platelet binding event stimulates platelet activation, recruitment, and activation of the clotting cascade, promoting thrombus formation.


OBJECTIVE
To characterize the inhibitory activity of a VWF inhibitory aptamer.


METHODS
Using in vitro selection, aptamer stabilization, and conjugation to a 20-kDa poly(ethylene glycol), we generated a nuclease-resistant aptamer, ARC1779, that binds to the VWF A1-domain with high affinity (K(D) approximately 2 nM). The aptamer was assessed for inhibition of VWF-induced platelet aggregation. In vitro inhibition of platelet adhesion was assessed on collagen-coated slides and injured pig aortic segments. In vivo activity was assessed in a cynomolgus monkey carotid electrical injury thrombosis model.


CONCLUSIONS
ARC1779 inhibited botrocetin-induced platelet aggregation (IC90 approximately 300 nM) and shear force-induced platelet aggregation (IC95 approximately 400 nM). It reduced adhesion of platelets to collagen-coated matrices and formation of platelet thrombi on denuded porcine arteries. ARC1779 also inhibited the formation of occlusive thrombi in cynomolgus monkeys. We have discovered a novel anti-VWF aptamer that could have therapeutic use as an anti-VWF agent in the setting of VWF-mediated thrombosis.
Diener
J L
JL
Immune Disease Institute and Department of Pathology, Harvard Medical School, Boston, MA, USA.
Daniel Lagassé
H A
HA
Duerschmied
D
D
Merhi
Y
Y
Tanguay
J-F
JF
Hutabarat
R
R
Gilbert
J
J
Wagner
D D
DD
Schaub
R
R
D000818:Animals; D052157:Aptamers, Nucleotide / Q000494:pharmacology*; D001158:Arteries / Q000293:injuries; D001483:Base Sequence; D017931:DNA Primers; D004558:Electric Stimulation; D008252:Macaca fascicularis; D009690:Nucleic Acid Conformation; D015539:Platelet Activation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D013552:Swine; D013927:Thrombosis / Q000517:prevention & control*; D014841:von Willebrand Factor / Q000037:antagonists & inhibitors* / Q000235:genetics
C526287:ARC 1779; D052157:Aptamers, Nucleotide; D017931:DNA Primers; D010975:Platelet Aggregation Inhibitors; D014841:von Willebrand Factor