title: Platelet-independent adhesion of calcium-loaded erythrocytes to von Willebrand factor.
abstract: Adhesion of erythrocytes to endothelial cells lining the vascular wall can cause vaso-occlusive events that impair blood flow which in turn may result in ischemia and tissue damage. Adhesion of erythrocytes to vascular endothelial cells has been described in multiple hemolytic disorders, especially in sickle cell disease, but the adhesion of normal erythrocytes to endothelial cells has hardly been described. It was shown that calcium-loaded erythrocytes can adhere to endothelial cells. Because sickle erythrocyte adhesion to ECs can be enhanced by ultra-large von Willebrand factor multimers, we investigated whether calcium loading of erythrocytes could promote binding to endothelial cells via ultra-large von Willebrand factor multimers. We used (immunofluorescent) live-cell imaging of washed erythrocytes perfused over primary endothelial cells at venular flow rate. Using this approach, we show that calcium-loaded erythrocytes strongly adhere to histamine-stimulated primary human endothelial cells. This adhesion is mediated by ultra-large von Willebrand factor multimers. Von Willebrand factor knockdown or ADAMTS13 cleavage abolished the binding of erythrocytes to activated endothelial cells under flow. Platelet depletion did not interfere with erythrocyte binding to von Willebrand factor. Our results reveal platelet-independent adhesion of calcium-loaded erythrocytes to endothelium-derived von Willebrand factor. Erythrocyte adhesion to von Willebrand factor may be particularly relevant for venous thrombosis, which is characterized by the formation of erythrocyte-rich thrombi.
authors.affiliation: Department of Molecular Cell Biology, Sanquin-Academic Medical Center Landsteiner Laboratory, Amsterdam, The Netherlands.
authors.forename: Michel W J
authors.identifier: http://orcid.org/0000-0003-2739-8808
authors.initials: MW
authors.lastname: Smeets
authors.affiliation: Department of Plasma Proteins, Sanquin-Academic Medical Center Landsteiner Laboratory, Amsterdam, The Netherlands.
authors.forename: Ruben
authors.initials: R
authors.lastname: Bierings
authors.affiliation: Department of Plasma Proteins, Sanquin-Academic Medical Center Landsteiner Laboratory, Amsterdam, The Netherlands.
authors.forename: Henriet
authors.initials: H
authors.lastname: Meems
authors.affiliation: Department of Molecular Cell Biology, Sanquin-Academic Medical Center Landsteiner Laboratory, Amsterdam, The Netherlands.
authors.forename: Frederik P J
authors.initials: FP
authors.lastname: Mul
authors.affiliation: Department of Pediatric Oncology/Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Dirk
authors.initials: D
authors.lastname: Geerts
authors.affiliation: Department of Intensive Care Medicine, Amsterdam Medical Center, Amsterdam, The Netherlands.
authors.forename: Alexander P J
authors.initials: AP
authors.lastname: Vlaar
authors.affiliation: Department of Plasma Proteins, Sanquin-Academic Medical Center Landsteiner Laboratory, Amsterdam, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Voorberg
authors.affiliation: Department of Molecular Cell Biology, Sanquin-Academic Medical Center Landsteiner Laboratory, Amsterdam, The Netherlands.|Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Hordijk
mesh_terms: D000071120:ADAMTS13 Protein / Q000378:metabolism; D001792:Blood Platelets / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion; D002478:Cells, Cultured; D004912:Erythrocytes / Q000378:metabolism* / Q000502:physiology; D061307:Human Umbilical Vein Endothelial Cells / Q000502:physiology; D006801:Humans; D013927:Thrombosis / Q000378:metabolism*; D014841:von Willebrand Factor / Q000235:genetics / Q000378:metabolism*
chemical_list: D014841:von Willebrand Factor; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D002118:Calcium