TY - JOUR
T1 - Sustained thromboprophylaxis mediated by an RBC-targeted pro-urokinase zymogen activated at the site of clot formation
AU - Zaitsev, Sergei
AU - Spitzer, Dirk
AU - Murciano, Juan Carlos
AU - Ding, Bi Sen
AU - Tliba, Samira
AU - Kowalska, M. Anna
AU - Marcos-Contreras, Oscar A.
AU - Kuo, Alice
AU - Stepanova, Victoria
AU - Atkinson, John P.
AU - Poncz, Mortimer
AU - Cines, Douglas B.
AU - Muzykantov, Vladimir R.
PY - 2010/6/24
Y1 - 2010/6/24
N2 - Plasminogen activators (PAs) are used to treat life-threatening thrombosis, but not for thromboprophylaxis because of rapid clearance, risk of bleeding, and central nervous system (CNS) toxicity. We describe a novel strategy that may help to overcome these limitations by targeting a thrombin-activated PA pro-drug to circulating red blood cells (RBCs). We fused a single chain antibody (scFv Ter-119) that binds to mouse glycophorin A (GPA) with a variant human single-chain low molecular weight urokinase construct that can be activated selectively by thrombin (scFv/uPA-T). scFv/uPA-T bound specifically to mouse RBCs without altering their biocompatibility and retained its zymogenic properties until converted by thrombin into an active 2-chain molecule. As a result, RBC-bound scFv/uPA-T caused thrombin-induced fibrinolysis. One hour and 48 hours after intravenous (IV) injection in mice, approximately 70% and approximately 35% of scFv/uPA-T was retained in the blood, respectively, and approximately 95% of the circulating scFv/uPA-T remained bound to RBCs. A single IV injection of scFv/uPA-T provided effective prophylaxis against arterial and venous thrombosis for up to 24 hours. Thus, prophylactic delivery of RBC-targeted PA pro-drugs activated selectively at the site of clot formation represents a new approach to prevent thrombosis in clinical settings where the risk of clotting is high.
AB - Plasminogen activators (PAs) are used to treat life-threatening thrombosis, but not for thromboprophylaxis because of rapid clearance, risk of bleeding, and central nervous system (CNS) toxicity. We describe a novel strategy that may help to overcome these limitations by targeting a thrombin-activated PA pro-drug to circulating red blood cells (RBCs). We fused a single chain antibody (scFv Ter-119) that binds to mouse glycophorin A (GPA) with a variant human single-chain low molecular weight urokinase construct that can be activated selectively by thrombin (scFv/uPA-T). scFv/uPA-T bound specifically to mouse RBCs without altering their biocompatibility and retained its zymogenic properties until converted by thrombin into an active 2-chain molecule. As a result, RBC-bound scFv/uPA-T caused thrombin-induced fibrinolysis. One hour and 48 hours after intravenous (IV) injection in mice, approximately 70% and approximately 35% of scFv/uPA-T was retained in the blood, respectively, and approximately 95% of the circulating scFv/uPA-T remained bound to RBCs. A single IV injection of scFv/uPA-T provided effective prophylaxis against arterial and venous thrombosis for up to 24 hours. Thus, prophylactic delivery of RBC-targeted PA pro-drugs activated selectively at the site of clot formation represents a new approach to prevent thrombosis in clinical settings where the risk of clotting is high.
UR - http://www.scopus.com/inward/record.url?scp=77954687045&partnerID=8YFLogxK
U2 - 10.1182/blood-2010-01-261610
DO - 10.1182/blood-2010-01-261610
M3 - Article
C2 - 20410503
AN - SCOPUS:77954687045
SN - 0006-4971
VL - 115
SP - 5241
EP - 5248
JO - Blood
JF - Blood
IS - 25
ER -