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Ferrata Storti Foundation
Haematologica 2021 Volume 106(6):1616-1623
Coagulation & its Disorders
Fibrinogen interaction with complement C3: a potential therapeutic target to reduce thrombosis risk
Rhodri J. King,1* Katharina Schuett,2* Christian Tiede,3 Vera Jankowski,4 Vicky John,1 Abhi Trehan,1 Katie Simmons,5 Sreenivasan Ponnambalam,6 Robert F. Storey,7 Colin W.G. Fishwick,5 Michael J. McPherson,3 Darren C. Tomlinson3 and Ramzi A. Ajjan1
1Leeds Institute for Cardiovascular and Metabolic Medicine, Leeds University, Leeds, UK; 2Department of Internal Medicine I, University Hospital Aachen, Aachen, Germany, 3Bioscreening Technology Group in the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK, 4Institute for Molecular and Cardiovascular Research, Aachen University, Aachen, Germany, 5School of Chemistry, University of Leeds, Leeds, UK, 6School of Molecular & Cellular Biology, University of Leeds, Leeds, UK and 7School of Medicine, University of Sheffield, Sheffield, UK
*RJK and KS contributed equally as co-first authors.
ABSTRACT
Complement C3 binds fibrinogen and compromises fibrin clot lysis, thereby enhancing the risk of thrombosis. We investigated the role of the fibrinogen-C3 interaction as a novel therapeutic target to reduce thrombosis risk by analyzing: (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 modeling evaluated C3 and fibrinogen interaction sites. Novel synthetic conformational proteins, termed affimers, were used to modulate the C3-fibrinogen interaction and fibri- nolysis. C3 purified from patients with type 1 diabetes showed enhanced prolongation of fibrinolysis compared with healthy control protein (195±105 and 522±166 s, respectively; P=0.04), with consistent effects but a wider range (5-51% and 5-18% lysis prolongation, respectively). Peptide microarray screening identified two potential C3-fibrinogen interaction sites within the fibrinogen b chain (residues 424-433 and 435-445). One fibrinogen-binding affimer that was isolated displayed sequence identity with C3 in an exposed area of the protein. This affimer abolished C3- induced prolongation of fibrinolysis (728±25.1 s to 632±23.7 s; 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 b-chain and disruption of the fibrinogen-C3 interaction using affimer proteins enhances fibrinolysis, which represents a potential novel tool to reduce thrombosis in high-risk individuals.
Introduction
Hypofibrinolysis is associated with increased risk of atherothrombotic events.1-3 Although most studies have only shown an association between hypofibrinolysis and cardiovascular disease, a more recent longitudinal study in a large population of patients with acute coronary syndrome demonstrated that prolonged fibrin clot lysis is an independent predictor of cardiovascular mortality.4 Therefore, it was proposed that reducing residual thrombosis risk in patients with coronary artery disease requires targeting the fibrinolytic system in addition to administering antiplatelet therapies. Indeed the combination of anticoagulant and antiplatelet therapies reduces vascular thrombotic events but at the expense of increased risk of bleeding.5 Therefore, a more targeted approach is required which improves hypofibrinolysis
Correspondence:
RA AJJAN
r.ajjan@leeds.ac.uk
Received: October 1, 2019. Accepted: April 29, 2020. Pre-published: April 30, 2020.
https://doi.org/10.3324/haematol.2019.239558
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