title: Targeting recombinant thrombomodulin fusion protein to red blood cells provides multifaceted thromboprophylaxis.
abstract: Thrombin generates fibrin and activates platelets and endothelium, causing thrombosis and inflammation. Endothelial thrombomodulin (TM) changes thrombin's substrate specificity toward cleavage of plasma protein C into activated protein C (APC), which opposes its thrombotic and inflammatory activities. Endogenous TM activity is suppressed in pathologic conditions, and antithrombotic interventions involving soluble TM are limited by rapid blood clearance. To overcome this problem, we fused TM with a single chain fragment (scFv) of an antibody targeted to red blood cells. scFv/TM catalyzes thrombin-mediated generation of activated protein C and binds to circulating RBCs without apparent damage, thereby prolonging its circulation time and bioavailability orders of magnitude compared with soluble TM. In animal models, a single dose of scFv/TM, but not soluble TM, prevents platelet activation and vascular occlusion by clots. Thus, scFv/TM serves as a prodrug and provides thromboprophylaxis at low doses (0.15 mg/kg) via multifaceted mechanisms inhibiting platelets and coagulation.
authors.affiliation: Program in Targeted Therapeutics, Institute for Translational Medicine and Therapeutics, and Department of Pharmacology, University of Pennsylvania School of Medicine, 3400 Civic Center Blvd., Philadelphia, PA 19104-5158, USA.
authors.forename: Sergei
authors.initials: S
authors.lastname: Zaitsev
authors.forename: M Anna
authors.initials: MA
authors.lastname: Kowalska
authors.forename: Michael
authors.initials: M
authors.lastname: Neyman
authors.forename: Ronald
authors.initials: R
authors.lastname: Carnemolla
authors.forename: Samira
authors.initials: S
authors.lastname: Tliba
authors.forename: Bi-Sen
authors.initials: BS
authors.lastname: Ding
authors.forename: Aaron
authors.initials: A
authors.lastname: Stonestrom
authors.forename: Dirk
authors.initials: D
authors.lastname: Spitzer
authors.forename: John P
authors.initials: JP
authors.lastname: Atkinson
authors.forename: Mortimer
authors.initials: M
authors.lastname: Poncz
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Cines
authors.forename: Charles T
authors.initials: CT
authors.lastname: Esmon
authors.forename: Vladimir R
authors.initials: VR
authors.lastname: Muzykantov
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D018890:Chemoprevention / Q000379:methods*; D004330:Drosophila; D016503:Drug Delivery Systems / Q000379:methods*; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D006801:Humans; D051379:Mice; D008954:Models, Biological; D058990:Molecular Targeted Therapy / Q000379:methods; D011485:Protein Binding; D011486:Protein C / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism / Q000627:therapeutic use; D057127:Single-Chain Antibodies / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism / Q000627:therapeutic use; D018180:Thrombomodulin / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism / Q000627:therapeutic use; D013927:Thrombosis / Q000517:prevention & control*
chemical_list: D011486:Protein C; D011993:Recombinant Fusion Proteins; D057127:Single-Chain Antibodies; D018180:Thrombomodulin