Fibrinogen interaction with complement C3: a potential therapeutic target to reduce thrombosis risk

Haematologica, vol. 106, pp. 1616–1623

Abstract

Complement C3 binds fibrinogen and compromises fibrin clot lysis thereby enhancing thrombosis risk. We investigated the role of fibrinogen-C3 interaction as a novel therapeutic target to reduce thrombosis risk by analysing: i) consistency in the fibrinolytic properties of C3, ii) binding sites between fibrinogen and C3 and iii) modulation of fibrin clot lysis by manipulating fibrinogen-C3 interactions. Purified fibrinogen and C3 from the same individuals (n=24) were used to assess inter-individual variability in the anti-fibrinolytic effects of C3. Microarray screening and molecular modelling evaluated C3 and fibrinogen interaction sites. Novel synthetic conformational proteins, termed Affimers, were used to modulate C3-fibrinogen interaction and fibrinolysis. C3 purified from patients with type 1 diabetes showed enhanced prolongation of fibrinolysis compared with healthy control protein [195±105 and 522±166 seconds, respectively (p=0.04)], with consistent effects but a wider range (5-51% and 5-18% lysis prolongation, respectively). Peptide microarray screening identified 2 potential C3-fibrinogen interactions sites within fibrinogen β chain (residues 424-433, 435-445). One fibrinogen-binding Affimer was isolated that displayed sequence identity with C3 in an exposed area of the protein. This Affimer abolished C3-induced prolongation of fibrinolysis (728±25.1 seconds to 632±23.7 seconds, p=0.005) and showed binding to fibrinogen in the same region that is involved in C3-fibrinogen interactions. Moreover, it shortened plasma clot lysis of patients with diabetes, cardiovascular disease or controls by 7-11%. C3 binds fibrinogen β-chain and disruption of fibrinogen-C3 interaction using Affimer proteins enhances fibrinolysis, which represents a potential novel target tool to reduce thrombosis in high risk individuals.

Authors 13

1. Rhodri King
   Affiliation as printed

   Leeds Institute for Cardiovascular and Metabolic Medicine, Leeds, UK

2. Katharina Andrea Schuett Aachen Department of Internal Medicine I (Cardiology)

   Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Department of Internal Medicine I, University Hospital RWTH Aachen, Germany

3. Christian Tiede

   University of Leeds

   Affiliation as printed

   Bioscreening Technology Group,School of Molecular and Cellular Biology, University of Leeds, UK

4. Vera Jankowski Aachen Institute for Molecular and Cardiovascular Research

   RWTH Aachen University

   Affiliation as printed

   Institute for Molecular and Cardiovascular Research, Aachen University, Germany

5. V John
   Affiliation as printed

   Leeds Institute for Cardiovascular and Metabolic Medicine, Leeds, UK

6. A. Trehan
   Affiliation as printed

   Leeds Institute for Cardiovascular and Metabolic Medicine, Leeds, UK

7. Katie J. Simmons

   University of Leeds

   Affiliation as printed

   School of Chemistry, University of Leeds, Leeds, UK

8. Sreenivasan Ponnambalam

   University of Leeds

   Affiliation as printed

   School of Molecular and Cellular Biology, University of Leeds, Leeds, UK

9. Robert F. Storey

   University of Sheffield

   Affiliation as printed

   School of Medicine, University of Sheffield, Sheffield, UK

10. Colin W. G. Fishwick

    University of Leeds

    Affiliation as printed

    School of Chemistry, University of Leeds, Leeds, UK

11. Michael J. McPherson

    University of Leeds

    Affiliation as printed

    Bioscreening Technology Group, School of Molecular and Cellular Biology, University of Leeds, UK

12. Darren Charles Tomlinson

    University of Leeds

    Affiliation as printed

    Bioscreening Technology Group, School of Molecular and Cellular Biology, University of Leeds, UK

13. Ramzi Ajjan
    Affiliation as printed

    Leeds Institute for Cardiovascular and Metabolic Medicine, Leeds, UK