OC 76.1 - Functional characterization and structural modeling of DNA-aptamers targeting activated coagulation Factor XIII

Wednesday, July 13, 2022

10:15 AM – 10:30 AM

Location: ExCel Center, ICC Capital Suite Room 2-4

Presentation Format: In-Person

Presenting Author(s)

Nasim Shahidi Hamedani, PharmD PhD

Scientific Staff Member
University Hospital Bonn; Institute of Experimental Haematologie and Transfusion Medicine
Bonn, Nordrhein-Westfalen, Germany

Co-Author(s)

Arijit Biswas, PD Dr (Biol)

Scientist
Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn
Bonn, Nordrhein-Westfalen, Germany
OR

Oliver Rudan

PhD student
Department of Integrated Oncology, CIO Bonn, University Hospital Bonn
Bonn, Nordrhein-Westfalen, Germany
CM

Carlotta Meyring

Bachelor student
Institute of Experimental Hematology and Transfusion Medicine, University Hospital Bonn
Bonn, Nordrhein-Westfalen, Germany
GM

Günter Mayer

Professor
Life and Medical Sciences Institute, University of Bonn
Bonn, Nordrhein-Westfalen, Germany
Johannes Oldenburg

Professor, Chairman and Director
University Clinic Bonn AöR, Institute of Experimental Haematology and Transfusion Medicine, Bonn, Germany
Bonn, Nordrhein-Westfalen, Germany
JM

Jens Müller

Scientific Director
Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn
Bonn, Nordrhein-Westfalen, Germany
BP

Bernd Pötzsch

Professor
Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn
Bonn, Nordrhein-Westfalen, Germany

Background: Coagulation factor XIII (FXIII) is a protransglutaminase which plays an important role in clot stabilization and composition by cross-linking the α- and γ-chains of fibrin and increasing the resistance of the clot to mechanical and proteolytic challenges. FXIII inhibition might lead to higher susceptibility of formed clot to fibrinolysis.

Aims: To study the inhibitory effect of FXIIIa-binding aptamers on clot formation and lysis.

Methods: In this study, we selected six DNA aptamers specific for activated FXIII (FXIIIa) using Capillary Electrophoresis-Systematic Evolution of Ligands by EXponential enrichment (CE-SELEX) and investigated the functional characterization of FXIIIa after aptamer binding in terms of fibrinogen binding of FXIIIa, alpha2-antiplasmin (α2AP) incorporation to fibrinogen and fibrin clot formation using plasma-based thromboelastometry (rotational thromboelastometry analysis, ROTEM).

Results: One of these aptamers, named FA12, efficiently captures FXIIIa even in the presence of zymogenic FXIII subunits. Furthermore, this aptamer inhibits the incorporation of FXIII and α2-antiplasmin (α2AP) into fibrin(ogen) with IC50-values of 38 nM and 17 nM, respectively. In addition to FA12, also another aptamer, FA2, demonstrated significant effects in ROTEM analysis where spiking of the aptamers into plasma decreased clot stiffness and elasticity (p < 0.0001). The structure–function correlations determined by combining modeling/docking strategies with quantitative in vitro assays revealed spatial overlap of the FA12 binding site with the binding sites of two FXIII substrates, fibrinogen and α2AP, while FA2 binding sites only overlap those of fibrinogen.

Conclusion(s): Two DNA aptamers specific for FXIIIa could inhibit incorporation of FXIIIa and α2AP to fibrin clot and therefore can be considered as an interesting candidate molecule for the development of FXIIIa-targeting therapeutic strategies.