von Willebrand factor A1 domain can adequately substitute for A3 domain in recruitment of flowing platelets to collagen

BACKGROUND: Binding of von Willebrand factor (VWF) to platelet GPIbalpha and to collagen is attributed to VWF A1 and A3 domains, respectively. OBJECTIVES: Using VWF, VWF lacking A1 (DeltaA1-VWF) or A3 (DeltaA3-VWF) and VWF with defective A3 (H1786A-VWF), in combination with recombinant A1 (residues 1262-1492) or A3 (residues 1671-1878), fused to glutathione-S-transferase (GST-A1 and GST-A3), we have re-investigated the role of A1 in platelet recruitment to surfaces of collagen. METHODS AND RESULTS: In flow, measurable binding of DeltaA3-VWF occurred to horse tendon, but also to human type III collagen. GST-A1 and GST-A3 both competed for binding of DeltaA1-VWF and DeltaA3-VWF to horse tendon collagen fibrils in static conditions and to human collagen III during plasmon surface resonance studies, substantiating overlapping binding sites on both collagens for A1 and A3. Heparin did not affect A3-mediated binding of VWF and DeltaA1-VWF, but inhibited binding to horse tendon collagen of GST-A1 and DeltaA3-VWF. Furthermore, A1-mediated binding to type III collagen of DeltaA3-VWF binding was strongly salt-sensitive. During perfusions at wall shear rate 2500 s(-1) of calcein-labeled platelets in reconstituted blood, DeltaA3-VWF and H1786A-VWF triggered platelet binding to horse tendon collagen comparably and as potently as VWF, and to human type III collagen, only fivefold less potently, DeltaA1-VWF being inactive. Additional flow-controlled interaction studies with DeltaA3-VWF, H1786A-VWF, the collagen-VWF antagonist saratin, heparin and the VWF neutralizing antibody 82D6A3 confirmed that H1786A-VWF binds to collagen exclusively via A1. CONCLUSION: Hence, in shear forces the VWF A1 domain can assume the role of A3 to trigger substantial platelet recruitment to human collagen fibres.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Binding of von Willebrand factor (VWF) to platelet GPIbalpha and to collagen is attributed to VWF A1 and A3 domains, respectively.

Leech-derived molecules this paper discusses, each with a full profile in the ASH compound registry:

Erfahren Sie, wie diese Forschung mit der klinischen Praxis verknüpft ist

More peer-reviewed studies in Speichel-Pharmakologie.

• Novel Leech Antimicrobial Peptides — Hirunipins — Kumar et al. (2025)
• 434 Salivary Proteins — Integrated Proteomics of Hirudo medicinalis — Liu et al. (2019)
• Medicinal Leech Genome Assembly — Anticoagulant Gene Catalog — Kvist et al. (2020)
• Effects of hirudotherapy on liver functions, lipid profile, and insulin sensitivity in rats with metabolic syndrome — Bilden A et al. (2026)
• Efficacy and Safety of Hirudotherapy for Improving Sperm Quality Parameters in Male Infertility: A Randomized Controlled Trial — Abtahi-Forooshani M et al. (2026)
• [Medicinal leeches and hirudotherapy] — Gödekmerdan A et al. (2011)
• PEROXIDATION OF SALIVA LIPIDS IN PATIENTS WITH POSTCOVID SYNDROME DURING HIRUDOTHERAPY — Serikbayeva S et al. (2024)
• Medicinal leech therapy in pain syndromes: a narrative review — Koeppen D, Aurich M, Rampp T (2014)
• Leech therapy in the treatment of a penile haematoma in a stallion — Nowicki A, Jaworska J, Baranski W (2021)
• Leech therapy (Hirudo medicinalis) attenuates testicular damages induced by testicular ischemia/reperfusion in an animal model — Davoodi F et al. (2021)

Browse all ASH-analysed research →