Conformational activation and inhibition of von Willebrand factor by targeting its autoinhibitory module

Arce, Nicholas A.; Markham-Lee, Zoe; Liang, Qian; Najmudin, Shabir; Legan, Emily R.; Dean, Gabrielle; Su, Ally J.; Wilson, Moriah S.; Sidonio, Robert F.; Lollar, Pete; Emsley, Jonas; Li, Renhao

Abstract

Activation of von Willebrand factor (VWF) is a tightly controlled process governed primarily by local elements around its A1 domain. Recent studies suggest that the O-glycosylated sequences flanking the A1 domain constitute a discontinuous and force-sensitive autoinhibitory module (AIM), although its extent and conformation remains controversial. Here, we used a targeted screening strategy to identify two groups of nanobodies. One group, represented by clone 6D12, is conformation-insensitive and binds the N-terminal AIM (NAIM) sequence that is distal from A1. 6D12 activates human VWF and induces aggregation of platelet-rich plasma at submicromolar concentrations. The other group, represented by clones Nd4 and Nd6, is conformation-sensitive and targets the C-terminal AIM (CAIM). Nd4 and Nd6 inhibit ristocetin-induced platelet aggregation and reduce VWF-mediated platelet adhesion under flow. A crystal structure of Nd6 in complex with AIM-A1 shows a novel conformation of both CAIM and NAIM that are primed to interact, providing a model of steric hindrance stabilized by the AIM as the mechanism for regulating GPIbα binding to VWF. Hydrogen-deuterium exchange mass spectrometry analysis shows that binding of 6D12 induces the exposure of the GPIbα-binding site in the A1 domain, but binding of inhibitory nanobodies reduces it. Overall, these results suggest that the distal portion of NAIM is involved in specific interactions with CAIM, and that binding of nanobodies to the AIM could either disrupt its conformation to activate VWF or stabilize its conformation to upkeep VWF autoinhibition. These reported nanobodies could facilitate future studies of VWF functions and related pathologies.

Citation

Arce, N. A., Markham-Lee, Z., Liang, Q., Najmudin, S., Legan, E. R., Dean, G., …Li, R. (2024). Conformational activation and inhibition of von Willebrand factor by targeting its autoinhibitory module. Blood, 143(19), 1992-2004. https://doi.org/10.1182/blood.2023022038

• Journal Article Type: Article
• Acceptance Date: Jan 19, 2024
• Online Publication Date: Jan 30, 2024
• Publication Date: May 9, 2024
• Deposit Date: Feb 5, 2024
• Publicly Available Date: Feb 5, 2024
• Journal: Blood
• Print ISSN: 0006-4971
• Electronic ISSN: 1528-0020
• Publisher: American Society of Hematology
• Peer Reviewed: Peer Reviewed
• Volume: 143
• Issue: 19
• Pages: 1992-2004
• DOI: https://doi.org/10.1182/blood.2023022038
• Keywords: Cell Biology; Hematology; Immunology; Biochemistry
• Public URL: https://nottingham-repository.worktribe.com/output/30667590
• Publisher URL: https://ashpublications.org/blood/article-abstract/doi/10.1182/blood.2023022038/514761/Conformational-activation-and-inhibition-of-von?redirectedFrom=fulltext
• Additional Information: This research was originally published in Blood. Nicholas A. Arce, Zoe Markham-Lee, Qian Liang, Shabir Najmudin, Emily R. Legan, Gabrielle Dean, Ally J. Su, Moriah S. Wilson, Robert F. Sidonio, Pete Lollar, Jonas Emsley, Renhao Li; Conformational activation and inhibition of von Willebrand factor by targeting its autoinhibitory module. Blood 2024; 143 (19): 1992–2004© the American Society of Hematology.