Endothelial targeting of a recombinant construct fusing a PECAM-1 single-chain variable antibody fragment (scFv) with prourokinase facilitates prophylactic thrombolysis in the pulmonary vasculature.
Means to prevent thrombus extension and local recurrence remain suboptimal, in part because of the limited effectiveness of existing thrombolytics. In theory, plasminogen activators could be used for this purpose if they could be anchored to the vascular lumen by targeting stably expressed, noninternalized determinants such as platelet-endothelial-cell adhesion molecule 1 (PECAM-1). We designed a recombinant molecule fusing low-molecular-weight single-chain prourokinase plasminogen activator (lmw-scuPA) with a single-chain variable fragment (scFv) of a PECAM-1 antibody to generate the prodrug scFv/lmw-scuPA. Cleavage by plasmin generated fibrinolytically active 2-chain lmw-uPA. This fusion protein (1) bound specifically to PECAM-1-expressing cells; (2) was rapidly cleared from blood after intravenous injection; (3) accumulated in the lungs of wild-type C57BL6/J, but not PECAM-1 null mice; and (4) lysed pulmonary emboli formed subsequently more effectively than lmw-scuPA, thereby providing support for the concept of thromboprophylaxis using recombinant scFv-fibrinolytic fusion proteins that target endothelium.
Ding
Bi-Sen
BS
Department of Pharmacology, IFEM, 1 John Morgan Bldg, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, PA 19104-6068, USA.
Gottstein
Claudia
C
Grunow
Andrea
A
Kuo
Alice
A
Ganguly
Kumkum
K
Albelda
Steven M
SM
Cines
Douglas B
DB
Muzykantov
Vladimir R
VR
D000818:Animals; D002460:Cell Line; D004330:Drosophila; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007128:Immunoglobulin Fragments / Q000235:genetics / Q000378:metabolism*; D008168:Lung / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013927:Thrombosis / Q000378:metabolism* / Q000473:pathology*; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism*
D007128:Immunoglobulin Fragments; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011994:Recombinant Proteins; D014568:Urokinase-Type Plasminogen Activator; C067551:saruplase