title: Actin-binding proteins differentially regulate endothelial cell stiffness, ICAM-1 function and neutrophil transmigration.
abstract: Chronic vascular inflammation is driven by interactions between activated leukocytes and the endothelium. Leukocyte β2-integrins bind to endothelial intercellular adhesion molecule 1 (ICAM-1), which allows leukocyte spreading, crawling and transendothelial migration. Leukocytes scan the vascular endothelium for permissive sites to transmigrate, which suggests that there is apical membrane heterogeneity within the endothelium. However, the molecular basis for this heterogeneity is unknown. Leukocyte adhesion induces ICAM-1 clustering, which promotes its association to the actin-binding proteins filamin B, α-actinin-4 and cortactin. We show that these endothelial proteins differentially control adhesion, spreading and transmigration of neutrophils. Loss of filamin B, α-actinin-4 and cortactin revealed adaptor-specific effects on a nuclear-to-peripheral gradient of endothelial cell stiffness. By contrast, increasing endothelial cell stiffness stimulates ICAM-1 function. We identify endothelial α-actinin-4 as a key regulator of endothelial cell stiffness and of ICAM-1-mediated neutrophil transmigration. Finally, we found that the endothelial lining of human and murine atherosclerotic plaques shows elevated levels of α-actinin-4. These results identify endothelial cell stiffness as an important regulator of endothelial surface heterogeneity and of ICAM-1 function, which in turn controls the adhesion and transmigration of neutrophils.
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center and Swammerdam Institute of Life Sciences, University of Amsterdam, 1066 CX Amsterdam, The Netherlands a.schaefer@sanquin.nl p.hordijk@sanquin.nl.
authors.forename: Antje
authors.initials: A
authors.lastname: Schaefer
authors.affiliation: Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen 6525 GA, The Netherlands.
authors.forename: Joost
authors.initials: J
authors.lastname: Te Riet
authors.affiliation: Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Katja
authors.initials: K
authors.lastname: Ritz
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center and Swammerdam Institute of Life Sciences, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Hoogenboezem
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center and Swammerdam Institute of Life Sciences, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
authors.forename: Eloise C
authors.initials: EC
authors.lastname: Anthony
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center and Swammerdam Institute of Life Sciences, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
authors.forename: Frederik P J
authors.initials: FP
authors.lastname: Mul
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Carlie J
authors.initials: CJ
authors.lastname: de Vries
authors.affiliation: Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Mat J
authors.initials: MJ
authors.lastname: Daemen
authors.affiliation: Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen 6525 GA, The Netherlands.
authors.forename: Carl G
authors.initials: CG
authors.lastname: Figdor
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center and Swammerdam Institute of Life Sciences, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
authors.forename: Jaap D
authors.initials: JD
authors.lastname: van Buul
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center and Swammerdam Institute of Life Sciences, University of Amsterdam, 1066 CX Amsterdam, The Netherlands a.schaefer@sanquin.nl p.hordijk@sanquin.nl.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Hordijk
mesh_terms: D000185:Actinin / Q000235:genetics / Q000378:metabolism*; D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000235:genetics; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D064448:Filamins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D008297:Male; D008387:Marine Toxins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009504:Neutrophils / Q000502:physiology*; D058226:Plaque, Atherosclerotic / Q000235:genetics / Q000378:metabolism*; D057705:Transendothelial and Transepithelial Migration
chemical_list: C111453:ACTN4 protein, human; D000199:Actins; D064448:Filamins; D008387:Marine Toxins; D000185:Actinin; D018799:Intercellular Adhesion Molecule-1; C066979:contractin A
keywords: Adhesion; Endothelium; Inflammation; Transmigration