A fusion protein with improved thrombolytic effect and low bleeding risk

Thromb Haemost. 2009 Dec;102(6):1194-203. doi: 10.1160/TH09-04-0235.

Abstract

To resolve the therapeutic dilemma between efficacy of thrombolysis and bleeding risk associated with the use of a combination of thrombolytic and anticoagulant treatments, we created a fusion protein. Staphylokinase was fused to the N-terminus of hirudin using thrombin recognition sequence as linker peptide, resulting in a fusion protein STH. We hypothesised that STH would be cleaved by thrombin at the thrombus site, releasing staphylokinase and hirudin to perform bifunctionally, and attenuating bleeding risk. SDS-PAGE and Western blot analyses indicated that the linker peptide could be specially recognised and cleaved by thrombin. Amidolytic and thromboelastogram assays showed that the N-terminus of hirudin in STH was blocked by staphylokinase and linker peptide, impeding hirudin's anticoagulant activity. Once cleaved, STH displayed 35.7% of the anticoagulant activity of equimolar hirudin and exhibited anticoagulant effects in the fibrin clot lysis assay. Thrombin-binding and fibrin clot lysis assays showed that the C-terminus of hirudin retained its high affinity for thrombin. Moreover, STH showed improved thrombolytic effects and a lower bleeding risk in animals. Thus, STH may have the capacity to perform bifunctionally and release anticoagulant activity in a thrombus-targeted manner in vivo, which may reduce the bleeding risk that often accompanies high thrombolytic efficacy in the treatment of thromboembolic diseases.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cattle
  • DNA Primers / genetics
  • Disease Models, Animal
  • Fibrinolytic Agents / chemistry
  • Fibrinolytic Agents / pharmacology*
  • Hemorrhage / prevention & control
  • Hirudins / chemistry
  • Hirudins / genetics
  • Hirudins / pharmacology
  • Humans
  • In Vitro Techniques
  • Metalloendopeptidases / chemistry
  • Metalloendopeptidases / genetics
  • Metalloendopeptidases / pharmacology
  • Mice
  • Plasminogen / metabolism
  • Rats
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / pharmacology
  • Thrombelastography
  • Thrombin / metabolism
  • Thromboembolism / drug therapy
  • Thrombolytic Therapy / adverse effects
  • Thrombolytic Therapy / methods
  • Vena Cava, Inferior

Substances

  • DNA Primers
  • Fibrinolytic Agents
  • Hirudins
  • Recombinant Fusion Proteins
  • Plasminogen
  • Thrombin
  • Metalloendopeptidases
  • auR protein, Staphylococcus aureus