TY - JOUR
T1 - Structural and therapeutic insights from the species specificity and in vivo antithrombotic activity of a novel αIIb-specific αIIbβ3 antagonist
AU - Blue, Robert
AU - Kowalska, M. Anna
AU - Hirsch, Jessica
AU - Murcia, Marta
AU - Janczak, Christin A.
AU - Harrington, Amanda
AU - Jirouskova, Marketa
AU - Li, Jihong
AU - Fuentes, Rudy
AU - Thornton, Michael A.
AU - Filizola, Marta
AU - Poncz, Mortimer
AU - Coller, Barry S.
PY - 2009
Y1 - 2009
N2 - We previously reported on a novel compound (Compound 1; RUC-1) identified by high-throughput screening that inhibits human αIIbβ3. RUC-1 did not inhibit αVβ3, suggesting that it interacts with αIIb, and flexible ligand/rigid protein molecular docking studies supported this speculation. We have now studied RUC-1's effects on murine and rat platelets, which are less sensitive than human to inhibition by Arg-Gly-Asp (RGD) peptides due to differences in the αIIb sequences contributing to the binding pocket. We found that RUC-1 was much less potent in inhibiting aggregation of murine and rat platelets. Moreover, RUC-1 potently inhibited fibrinogen binding to murine platelets expressing a hybrid αIIbβ3 receptor composed of human αIIb and murine β3, but not a hybrid receptor composed of murine αIIb and human β3. Molecular docking studies of RUC-1 were consistent with the functional data. In vivo studies of RUC-1 administered intraperitoneally at a dose of 26.5 mg/kg demonstrated antithrombotic effects in both ferric chloride carotid artery and laser-induced microvascular injury models in mice with hybrid hαIIb/mβ3 receptors. Collectively, these data support RUC-1's specificity for αIIb, provide new insights into the αIIb binding pocket, and establish RUC-1's antithrombotic effects in vivo.
AB - We previously reported on a novel compound (Compound 1; RUC-1) identified by high-throughput screening that inhibits human αIIbβ3. RUC-1 did not inhibit αVβ3, suggesting that it interacts with αIIb, and flexible ligand/rigid protein molecular docking studies supported this speculation. We have now studied RUC-1's effects on murine and rat platelets, which are less sensitive than human to inhibition by Arg-Gly-Asp (RGD) peptides due to differences in the αIIb sequences contributing to the binding pocket. We found that RUC-1 was much less potent in inhibiting aggregation of murine and rat platelets. Moreover, RUC-1 potently inhibited fibrinogen binding to murine platelets expressing a hybrid αIIbβ3 receptor composed of human αIIb and murine β3, but not a hybrid receptor composed of murine αIIb and human β3. Molecular docking studies of RUC-1 were consistent with the functional data. In vivo studies of RUC-1 administered intraperitoneally at a dose of 26.5 mg/kg demonstrated antithrombotic effects in both ferric chloride carotid artery and laser-induced microvascular injury models in mice with hybrid hαIIb/mβ3 receptors. Collectively, these data support RUC-1's specificity for αIIb, provide new insights into the αIIb binding pocket, and establish RUC-1's antithrombotic effects in vivo.
UR - http://www.scopus.com/inward/record.url?scp=67651068728&partnerID=8YFLogxK
U2 - 10.1182/blood-2008-08-169243
DO - 10.1182/blood-2008-08-169243
M3 - Article
C2 - 19414864
AN - SCOPUS:67651068728
SN - 0006-4971
VL - 114
SP - 195
EP - 201
JO - Blood
JF - Blood
IS - 1
ER -