Bifunctional fusion protein targeting both FXIIa and FXIa displays potent anticoagulation effects

Area of Science:

• Biochemistry
• Pharmacology
• Thrombosis Research

Background:

• Anticoagulation therapy is crucial for treating thrombotic diseases.
• The intrinsic coagulation pathway, particularly factors FXIIa and FXIa, presents a low bleeding risk target.
• Dual targeting of FXIIa and FXIa for anticoagulation has not been previously investigated.

Purpose of the Study:

• To evaluate the anticoagulation and antithrombotic efficacy of a novel bifunctional fusion protein targeting both FXIIa and FXIa.
• To assess the safety profile, specifically bleeding risk, of this dual-targeting approach.

Main Methods:

• A fusion protein, Infestin-PN2KPI (IP), was engineered by linking FXIIa and FXIa inhibitors.
• Binding affinity and inhibitory activity of IP were confirmed using Surface Plasmon Resonance (SPR) and chromogenic assays.
• Anticoagulation and antithrombotic effects were assessed via aPTT, FeCl3-induced carotid artery thrombosis, and middle cerebral artery occlusion models.

Main Results:

• The fusion protein IP significantly prolonged activated partial thromboplastin time (aPTT), indicating anticoagulation.
• IP demonstrated potent antithrombotic activity and stroke prevention in vivo.
• Effective doses of IP were at least 50% lower than individual component inhibitors, with no observed increase in bleeding risk.

Conclusions:

• Simultaneous inhibition of FXIIa and FXIa via the bifunctional fusion protein IP is a viable and effective anticoagulation strategy.
• This dual-targeting approach offers a promising avenue for developing safer and more effective anticoagulant therapies.