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Blocking the initiation of coagulation by RNA aptamers to factor VIIa
C P Rusconi1, A Yeh, H K Lyerly
1Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA.
Abstract:
The tissue factor/factor VIIa complex is thought to be the primary initiator of most physiologic blood coagulation events. Because of its proximal role in this process, we sought to generate new inhibitors of tissue factor/factor VIIa activity by targeting factor VIIa. We employed a combinatorial RNA library and in vitro selection methods to isolate a high affinity, nuclease-resistant RNA ligand that binds specifically to coagulation factor VII/VIIa. This RNA inhibits the tissue factor-dependent activation of factor X by factor VIIa. Kinetic analyses of the mechanism of action of this RNA suggest that it antagonizes factor VIIa activity by preventing formation of a functional factor VII/tissue factor complex. Furthermore, this RNA significantly prolongs the prothrombin time of human plasma in a dose dependent manner, and has an in vitro half-life of approximately 15 h in human plasma. Thus, this RNA ligand represents a novel class of anticoagulant agents directed against factor VIIa.
Insights
Researchers developed a novel RNA ligand that inhibits factor VIIa, a key protein in blood clotting. This new anticoagulant agent effectively prolongs clotting time and shows promise for treating bleeding disorders.
Area of Science:
- Biochemistry
- Molecular Biology
- Hematology
Background:
- The tissue factor/factor VIIa complex initiates most physiological blood coagulation.
- Targeting factor VIIa offers a strategy for developing new anticoagulants.
Purpose of the Study:
- To generate novel inhibitors of tissue factor/factor VIIa activity by targeting factor VIIa.
- To isolate a high-affinity, nuclease-resistant RNA ligand that specifically binds to coagulation factor VII/VIIa.
Main Methods:
- Utilized a combinatorial RNA library and in vitro selection methods.
- Investigated the mechanism of action through kinetic analyses.
- Assessed the RNA's effect on prothrombin time and in vitro half-life in human plasma.
Main Results:
- Isolated a specific RNA ligand that binds to coagulation factor VII/VIIa.
- Demonstrated that the RNA inhibits tissue factor-dependent activation of factor X by factor VIIa.
- Observed significant, dose-dependent prolongation of prothrombin time in human plasma with an in vitro half-life of approximately 15 hours.
Conclusions:
- The identified RNA ligand antagonizes factor VIIa activity by preventing the formation of a functional factor VII/tissue factor complex.
- This RNA ligand represents a novel class of anticoagulant agents targeting factor VIIa.
- The findings suggest potential therapeutic applications for this RNA in managing coagulation disorders.