title: Fusion proteins comprising annexin V and Kunitz protease inhibitors are highly potent thrombogenic site-directed anticoagulants.
abstract: The anionic phospholipid, phosphatidyl-L-serine (PS), is sequestered in the inner layer of the plasma membrane in normal cells. Upon injury, activation, and apoptosis, PS becomes exposed on the surfaces of cells and sheds microparticles, which are procoagulant. Coagulation is initiated by formation of a tissue factor/factor VIIa complex on PS-exposed membranes and propagated through the assembly of intrinsic tenase (factor VIIIa/factor IXa), prothrombinase (factor Va/factor Xa), and factor XIa complexes on PS-exposed activated platelets. We constructed a novel series of recombinant anticoagulant fusion proteins by linking annexin V (ANV), a PS-binding protein, to the Kunitz-type protease inhibitor (KPI) domain of tick anticoagulant protein, an aprotinin mutant (6L15), amyloid beta-protein precursor, or tissue factor pathway inhibitor. The resulting ANV-KPI fusion proteins were 6- to 86-fold more active than recombinant tissue factor pathway inhibitor and tick anticoagulant protein in an in vitro tissue factor-initiated clotting assay. The in vivo antithrombotic activities of the most active constructs were 3- to 10-fold higher than that of ANV in a mouse arterial thrombosis model. ANV-KPI fusion proteins represent a new class of anticoagulants that specifically target the anionic membrane-associated coagulation enzyme complexes present at sites of thrombogenesis and are potentially useful as antithrombotic agents.
authors.affiliation: Division of Hematology, Department of Medicine, Washington University School of Medicine, St Louis, MO, USA.
authors.forename: Hsiu-Hui
authors.initials: HH
authors.lastname: Chen
authors.forename: Cristina P
authors.initials: CP
authors.lastname: Vicente
authors.forename: Li
authors.initials: L
authors.lastname: He
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Tollefsen
authors.forename: Tze-Chein
authors.initials: TC
authors.lastname: Wun
mesh_terms: D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017304:Annexin A5 / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000925:Anticoagulants / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects*; D002417:Cattle; D015951:Factor Xa / Q000378:metabolism; D006801:Humans; D051379:Mice; D023421:Models, Animal; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013552:Swine; D013927:Thrombosis / Q000378:metabolism*; D013997:Time Factors; D014357:Trypsin / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D017304:Annexin A5; D000925:Anticoagulants; D011480:Protease Inhibitors; D011993:Recombinant Fusion Proteins; D014357:Trypsin; D015951:Factor Xa