A Thrombin-Activatable Factor X Variant Corrects Hemostasis in a Mouse Model for Hemophilia A.

Abstract

Engineered recombinant factor X (FX) variants represent a promising strategy to bypass the tenase complex and restore hemostasis in hemophilia patients. Previously, a thrombin-activatable FX variant with fibrinopeptide-A replacing the activation peptide (FX-delAP/FpA) has been described in this regard. Here we show that FX-delAP/FpA is characterized by a sixfold shorter circulatory half-life compared with wild-type FX, limiting its therapeutical applicability. We therefore designed a variant in which the FpA sequence is inserted C-terminal to the FX activation peptide (FX/FpA). FX/FpA displayed a similar survival to wt-FX in clearance experiments and could be converted into FX by thrombin and other activating agents. In in vitro assays, FX/FpA efficiently restored thrombin generation in hemophilia A and hemophilia B plasmas, even in the presence of inhibitory antibodies. Expression following hydrodynamic gene transfer of FX/FpA restored thrombus formation in FVIII-deficient mice in a laser-induced injury model as well as hemostasis in a tail-clip bleeding model. Hemostasis after tail transection in FVIII-deficient mice was also corrected at 5 and 90 minutes after injection of purified FX/FpA. Our data indicate that FX/FpA represents a potential tenase-bypassing agent for the treatment of hemophilia patients with or without inhibitors.

• Authors: Vincent Muczynski, Sebastien Verhenne, Caterina Casari, Ghislaine Chérel, Laurence Panicot-Dubois, Paul Gueguen, Marc Trossaert, Christophe Dubois, Peter J Lenting, Cécile V Denis, Olivier D Christophe
• Journal: Thrombosis and haemostasis (Thromb Haemost) Vol. 119 Issue 12 Pg. 1981-1993 (Dec 2019) ISSN: 2567-689X [Electronic] Germany
• PMID: 31639831 (Publication Type: Journal Article)
• Copyright: Georg Thieme Verlag KG Stuttgart · New York.

Chemical References

• Antibodies
• Peptides
• Recombinant Proteins
• Fibrinopeptide A
• Factor X
• Thrombin

Topics

• Animals
• Antibodies (chemistry)
• Disease Models, Animal
• Factor X (genetics)
• Female
• Fibrinopeptide A (genetics)
• Genetic Variation
• Hemophilia A (genetics, therapy)
• Hemostasis
• Hepatocytes (metabolism)
• Kinetics
• Male
• Mice
• Mice, Inbred C57BL
• Microcirculation
• Peptides
• Protein Domains
• Recombinant Proteins (chemistry)
• Thrombin (chemistry)