Evidence map›Paper›PMID 40706961›Full record

ArticleJournal of thrombosis and haemostasis : JTH2025

Glycoprotein VI is a receptor for the PF4/anti-PF4 IgG complex and contributes to platelet activation in heparin-induced thrombocytopenia (HIT).

Ivo M B Francischetti, Kathryn E Dane, Ed L Galgo, Michael B Streiff, John F Andersen

Abstract read
In one paragraph

Article in Journal of thrombosis and haemostasis : JTH, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Ivo M B FrancischettiDepartment of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. Electronic address: ifranci3@jh.edu.
Kathryn E DaneDepartment of Pharmacy, The Johns Hopkins Hospital, Baltimore, Maryland, USA.
Ed L GalgoDepartment of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Michael B StreiffDepartment of Medicine, Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
John F AndersenLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA. Electronic address: jandersen@niaid.nih.gov.

Funding

Vector-Borne Diseases: Biology Of Vector Host RelationshipZ01AI000810 · NIAID · NIAID EXTRAMURAL ACTIVITIES · PI RIBEIRO, JOSE M · 1997 to 2008
$3.5M
Intramural NIH HHS Z01 AI000810
6 · The paper itself

Abstract

backgroundPlatelet factor 4 (PF4) plays a central role in heparin-induced thrombocytopenia (HIT). PF4 is a positively charged tetramer that forms immune complexes with anti-PF4 immunoglobulin G, activating platelets via FcγRIIA. Despite extensive study, a platelet receptor for PF4 within these complexes has not been clearly defined.

objectiveWe hypothesized that glycoprotein VI (GPVI), a collagen receptor known to interact with multiple ligands, binds PF4 and contributes to platelet activation in HIT.

methodsWe used platelet aggregation assays, surface plasmon resonance, and AlphaFold 3 modeling to investigate interactions between PF4, the HIT-mimicking monoclonal antibody KKO, and GPVI.

resultsPlatelet aggregation triggered by PF4/KKO or HIT patient sera was reduced by anti-GPVI antibodies or the anti-GPVI Fab fragment ACT017. Surface plasmon resonance showed that PF4 binds GPVI with a dissociation constant of Kd approximately equal to 1 μM, but PF4/KKO complexes exhibited enhanced binding, with a 5 to 17-fold reduction in dissociation rate and Kd approximately equal to 30 to 100 nM. This interaction was blocked by heparin. In contrast, the nonpathogenic anti-PF4 antibody RTO had no effect. AlphaFold 3 modeling predicted electrostatic interactions between anionic GPVI surfaces and the PF4/KKO complex, with PF4 tetramers contacting both the GPVI D2 domain and KKO Fab.

conclusionGPVI functions as a receptor for PF4/HIT antibody complex, engaging FcγRIIA and contributing to platelet activation in HIT.

Indexed as

AnticoagulantsHeparinImmunoglobulin GPlatelet Factor 4Receptors, IgGThrombocytopeniaAntigen-Antibody ComplexBinding SitesHumansModels, MolecularPlatelet AggregationPlatelet Membrane GlycoproteinsProtein BindingSurface Plasmon ResonanceAnticoagulantsAntigen-Antibody ComplexFc gamma receptor IIAHeparinImmunoglobulin GPF4 protein, humanPlatelet Factor 4Platelet Membrane Glycoproteinsplatelet membrane glycoprotein VIReceptors, IgGACT017AlphaFold 3collagenglenzocimabGPVIHITplateletsthrombosis

Identifiers

PMID40706961
PMCPMC12396540

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.