PB0337 - VWF binding to galectin-1 and -3: VWF glycosylation and implication on its function

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Patricia Lopes, MSc

PhD candidate
Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland
Dublin, Dublin, Ireland

Co-Author(s)

Ciara Byrne, PhD

Postdoc
RCSI Dublin
Dublin, Dublin, Ireland
Patricia Lopes, MSc

PhD candidate
Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland
Dublin, Dublin, Ireland
EK

Ellie Karampini

Post-Doctoral Fellow
Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland
Dublin, Dublin, Ireland
Jamie O'Sullivan

Lecturer/StAR Investigator in Vascular Biology
Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland.
Dublin, Dublin, Ireland
JO

James S. O'Donnell

Professor of Vascular Biology
Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, RCSI University of Medicine and Health Sciences, Dublin, Ireland.
Dublin, Dublin, Ireland

Background: Galectin-1 and -3 are galactoside sugar binding proteins that have been shown to circulate in plasma as a complex with Von Willebrand Factor (VWF). However little is known about how galectin binding can impact VWF biology and haemostasis. Therefore, binding of plasma derived (pd)VWF, recombinant (r)VWF and ABO specific-VWF to gal-1 and -3 was investigated.

Aims: We hypothesized that binding of VWF to galectin-1 and -3 is regulated by the glycans on VWF and might modulate VWF function.

Methods: Plasma derived-VWF was purified through gel filtration. To assess the role of sialic acid in regulating VWF-gal binding, α2-3,6,8,9 neuraminidase A was incubated with VWF, overnight at 37 °C. Binding of VWF to Gal-1 and -3, collagens III, IV, and VI and GPIbα were performed using plate-binding assays. To evaluate the influence of galectins on VWF-platelet interactions, light transmission aggregometry was used to measured percentage of platelet agglutination following VWF-Gal incubation.

Results: Binding of pdVWF to galectin-1 (p < 0.0001) and galectin-3 (p < 0.0001) was significantly higher compared to rVWF. The removal of sialic acid increased binding of pdVWF and rVWF to galectin-3 relative to their control counterparts (p < 0.001 and p< 0.0001, respectively). Binding to galectin-1 was also higher for pdVWF (p < 0.01), but not for rVWF. Interestingly, AB-VWF bound significantly more to galectin-1 (p < 0.0001) and galectin-3 (p < 0.0001) compared to O-VWF. No difference in VWF binding to collagen-III, IV, VI, and GP1bα or platelet agglutination was observed with addition of plasmatic concentrations of galectin-1 and -3.

Conclusion(s): Galectin-1 and -3 binds to VWF in a glycan dependent manner. Binding of VWF to collagen and platelets is not influenced by galectin-1 and -3.