title: Exploiting the kinetic interplay between GPIbα-VWF binding interfaces to regulate hemostasis and thrombosis.
abstract: Platelet-von Willebrand factor (VWF) interactions must be tightly regulated in order to promote effective hemostasis and prevent occlusive thrombus formation. However, it is unclear what role the inherent properties of the bond formed between the platelet receptor glycoprotein Ibα and the A1 domain of VWF play in these processes. Using VWF-A1 knock-in mice with mutations that enhance (I1309V) or disrupt (R1326H) platelet receptor glycoprotein Ibα binding, we now demonstrate that the kinetic interplay between two distinct contact surfaces influences the site and extent to which platelets bind VWF. Incorporation of R1326H mutation into the major site shortened bond lifetime, yielding defects in hemostasis and thrombosis comparable to VWF-deficient animals. Similarly, disrupting this region of contact with an allosteric inhibitor impaired human platelet accrual in damaged arterioles. In contrast, the I1309V mutation near the minor site prolonged bond lifetime, which was essential for the development of a type 2B-like VWD phenotype. However, combining the R1326H and I1309V mutations normalized both bond kinetics and the hemostatic and thrombotic properties of VWF. These findings broaden our understanding of mechanisms governing platelet-VWF interactions in health and disease, and underscore the importance of combined biophysical and genetic approaches in identifying potential therapeutic avenues for treating bleeding and thrombotic disorders.
authors.affiliation: Department of Pediatrics, Columbia University Medical Center, New York, NY;
authors.forename: Jianchung
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, Columbia University Medical Center, New York, NY;
authors.forename: Hairu
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Pediatrics, Columbia University Medical Center, New York, NY;
authors.forename: Alexander
authors.initials: A
authors.lastname: Diacovo
authors.affiliation: Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: X Long
authors.initials: XL
authors.lastname: Zheng
authors.affiliation: Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom; and.
authors.forename: Jonas
authors.initials: J
authors.lastname: Emsley
authors.affiliation: Department of Pediatrics, Columbia University Medical Center, New York, NY; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Diacovo
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D001792:Blood Platelets / Q000378:metabolism; D006487:Hemostasis; D006801:Humans; D007700:Kinetics; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008958:Models, Molecular; D009154:Mutation; D010973:Platelet Adhesiveness / Q000235:genetics; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013927:Thrombosis / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D014841:von Willebrand Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D019038:Platelet Glycoprotein GPIb-IX Complex; D014841:von Willebrand Factor