Galectin-1 and Galectin-3 Constitute Novel-Binding Partners for Factor VIII

Area of Science:

• Biochemistry
• Hematology
• Glycobiology

Background:

• Galectin-1 (Gal-1) and Galectin-3 (Gal-3) bind von Willebrand factor, modulating thrombus formation.
• Human Factor VIII (FVIII) shares similar glycan structures with von Willebrand factor.

Purpose of the Study:

• Investigate if galectins bind and modulate the activity of FVIII.
• Explore the potential impact of galectin-FVIII interactions on hemophilia A treatment.

Main Methods:

• Immunosorbant assays and surface plasmon resonance to assess binding affinity.
• Exoglycosidase and specific glycan digestion to identify binding sites.
• Functional assays to measure FVIII activity in the presence of galectins.

Main Results:

• Gal-1 and Gal-3 bind purified FVIII with high affinity, primarily through N-linked glycans.
• Gal-1 binding to FVIII significantly inhibited its procoagulant activity.
• Galectins showed differential binding to various recombinant FVIII products, potentially linked to glycosylation differences.

Conclusions:

• Galectin-1 and Galectin-3 are novel binding partners for FVIII.
• Galectin-1 binding influences FVIII's procoagulant activity.
• Glycosylation patterns of FVIII impact galectin binding, with implications for recombinant FVIII therapies.