Prophylactic thrombolysis by thrombin-activated latent prourokinase targeted to PECAM-1 in the pulmonary vasculature.
A recombinant prodrug, single-chain urokinase-type plasminogen activator (scuPA) fused to an anti-PECAM-1 antibody single-chain variable fragment (anti-PECAM scFv/scuPA) targets endothelium and augments thrombolysis in the pulmonary vasculature.(1) To avoid premature activation and inactivation and to limit systemic toxicity, we replaced the native plasmin activation site in scFv/low-molecular-weight (lmw)-scuPA with a thrombin activation site, generating anti-PECAM scFv/uPA-T that (1) is latent and activated by thrombin instead of plasmin; (2) binds to PECAM-1; (3) does not consume plasma fibrinogen; (4) accumulates in mouse lungs after intravenous injection; and (5) resists PA inhibitor PAI-1 until activated by thrombin. In mouse models of pulmonary thrombosis caused by thromboplastin and ischemia-reperfusion (I/R), scFv/uPA-T provided more potent thromboprophylaxis and greater lung protection than plasmin-sensitive scFv/uPA. Endothelium-targeted thromboprophylaxis triggered by a prothrombotic enzyme illustrates a novel approach to time- and site-specific regulation of proteolytic reactions that can be modulated for therapeutic benefit.
Department of Pharmacology, Institute for Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, USA.
Bi-Sen
BS
Ding
Nankang
N
Hong
Juan-Carlos
JC
Murciano
Kumkum
K
Ganguly
Claudia
C
Gottstein
Melpo
M
Christofidou-Solomidou
Steven M
SM
Albelda
Aron B
AB
Fisher
Douglas B
DB
Cines
Vladimir R
VR
Muzykantov
D000818:Animals; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism / Q000502:physiology*; D011485:Protein Binding; D011652:Pulmonary Circulation / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D013917:Thrombin / Q000502:physiology*; D015912:Thrombolytic Therapy; D014018:Tissue Distribution; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D005340:Fibrinogen; D013917:Thrombin; D014568:Urokinase-Type Plasminogen Activator; C067551:saruplase