1. A chimeric platelet-targeted urokinase prodrug selectively blocks new thrombus formation
- Author
-
Victoria Stepanova, Mortimer Poncz, M. Anna Kowalska, Michele P. Lambert, Don L. Siegel, Daniel D. Myers, Vincent Hayes, Daniel W. Bougie, Sergei Zaitsev, Richard H. Aster, Hyun Sook Ahn, Vladimir R. Muzykantov, Douglas B. Cines, Yuhuan Wang, and Rudy Fuentes
- Subjects
Blood Platelets ,Recombinant Fusion Proteins ,medicine.medical_treatment ,Mice, SCID ,030204 cardiovascular system & hematology ,Mice ,03 medical and health sciences ,Drug Delivery Systems ,0302 clinical medicine ,Thrombin ,Mice, Inbred NOD ,Fibrinolysis ,medicine ,Animals ,Humans ,Prodrugs ,Platelet ,Platelet activation ,Thrombus ,030304 developmental biology ,Mice, Knockout ,Urokinase ,0303 health sciences ,Chemistry ,Thrombosis ,General Medicine ,Prodrug ,medicine.disease ,Urokinase-Type Plasminogen Activator ,3. Good health ,Immunology ,Cancer research ,Fibrinolytic agent ,Research Article ,medicine.drug - Abstract
The use of fibrinolytic agents to prevent new thrombus formation is limited by an increased risk of bleeding due to lysis of hemostatic clots that prevent hemorrhage in damaged blood vessels. We sought to develop an agent that provides thromboprophylaxis without carrying a significant risk of causing systemic fibrinolysis or disrupting hemostatic clots. We previously showed that platelet (PLT) α granule-delivered urokinase plasminogen activator (uPA) is highly effective in preventing thrombosis, while being associated with little systemic fibrinolysis or bleeding. Here, we generated a chimeric prodrug composed of a single-chain version of the variable region of an anti-αIIbβ3 mAb fused to a thrombin-activatable, low-molecular-weight pro-uPA (PLT/uPA-T). PLT/uPA-T recognizes human αIIbβ3 on both quiescent and activated platelets and is enzymatically activated specifically by thrombin. We found that this prodrug binds tightly to human platelets even after gel filtration, has a prolonged half-life in mice transgenic for human αIIb compared with that of uPA-T, and prevents clot formation in a microfluidic system. Importantly, in two murine injury models, PLT/uPA-T did not lyse preexisting clots, even when administration was delayed by as little as 10 minutes, while it concurrently prevented the development of nascent thrombi. Thus, PLT/uPA-T represents the prototype of a platelet-targeted thromboprophylactic agent that selectively targets nascent over preexisting thrombi.
- Published
- 2015