R1205H (Vicenza) causes conformational changes in the von Willebrand factor D'D3 domains and enhances von Willebrand factor binding to clearance receptors LRP1 and SR-AI

J Thromb Haemost. 2024 Oct;22(10):2752-2760. doi: 10.1016/j.jtha.2024.06.023. Epub 2024 Jul 10.

Abstract

Background: von Willebrand factor (VWF)-R1205H variant (Vicenza) results in markedly enhanced VWF clearance in humans that has been shown to be largely macrophage-mediated. However, the biological mechanisms underlying this enhanced clearance remain poorly understood.

Objectives: This study aimed to investigate the roles of (i) specific VWF domains and (ii) different macrophage receptors in regulating enhanced VWF-R1205H clearance.

Methods: In vivo clearance of full-length and truncated wild-type (WT)-VWF and VWF with R1205 substitutions was investigated in VWF-/- mice. Plate-binding assays were employed to characterize VWF binding to purified scavenger receptor class A member 1 (SR-AI), low-density lipoprotein receptor-related protein-1 (LRP1) cluster II or cluster IV receptors, and macrophage galactose-type lectin.

Results: In full-length VWF missing the A1 domain, introduction of R1205H led to significantly enhanced clearance in VWF-/- mice compared with WT-VWF missing the A1 domain. Importantly, R1205H in a truncated VWF-D'D3 fragment also triggered increased clearance compared with WT-VWF-D'D3. Additional in vivo studies demonstrated that VWF-R1205K (which preserves the positive charge at 1205) exhibited normal clearance, whereas VWF-R1205E (which results in loss of the positive charge) caused significantly enhanced clearance, pinpointing the importance of the positive charge at VWF-R1205. In vitro plate-binding studies confirmed increased VWF-R1205H interaction with SR-AI compared with WT-VWF. Furthermore, significantly enhanced VWF-R1205H binding to LRP1 cluster IV (P < .001) and less marked enhanced binding to LRP1 cluster II (P = .034) was observed. In contrast, VWF-R1205H and WT-VWF demonstrated no difference in binding affinity to macrophage galactose-type lectin.

Conclusion: Disruption of the positive charge at amino acid R1205 causes conformational changes in the VWF-D'D3 domains and triggers enhanced LRP1-mediated and SR-AI-mediated clearance.

Keywords: VWF-R1205H (Vicenza); enhanced VWF clearance; type 1C VWD; von Willebrand disease; von Willebrand factor.

MeSH terms

  • Animals
  • Humans
  • Low Density Lipoprotein Receptor-Related Protein-1* / metabolism
  • Macrophages / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Protein Binding*
  • Protein Conformation
  • Protein Domains*
  • Scavenger Receptors, Class B
  • von Willebrand Factor* / metabolism

Substances

  • Low Density Lipoprotein Receptor-Related Protein-1
  • Lrp1 protein, mouse
  • Scarb1 protein, mouse
  • Scavenger Receptors, Class B
  • von Willebrand Factor