title: F-actin-anchored focal adhesions distinguish endothelial phenotypes of human arteries and veins.
abstract: OBJECTIVE
  Vascular endothelial-cadherin- and integrin-based cell adhesions are crucial for endothelial barrier function. Formation and disassembly of these adhesions controls endothelial remodeling during vascular repair, angiogenesis, and inflammation. In vitro studies indicate that vascular cytokines control adhesion through regulation of the actin cytoskeleton, but it remains unknown whether such regulation occurs in human vessels. We aimed to investigate regulation of the actin cytoskeleton and cell adhesions within the endothelium of human arteries and veins.
  
  
  RESULTS
  We used an ex vivo protocol for immunofluorescence in human vessels, allowing detailed en face microscopy of endothelial monolayers. We compared arteries and veins of the umbilical cord and mesenteric, epigastric, and breast tissues and find that the presence of central F-actin fibers distinguishes the endothelial phenotype of adult arteries from veins. F-actin in endothelium of adult veins as well as in umbilical vasculature predominantly localizes cortically at the cell boundaries. By contrast, prominent endothelial F-actin fibers in adult arteries anchor mostly to focal adhesions containing integrin-binding proteins paxillin and focal adhesion kinase and follow the orientation of the extracellular matrix protein fibronectin. Other arterial F-actin fibers end in vascular endothelial-cadherin-based endothelial focal adherens junctions. In vitro adhesion experiments on compliant substrates demonstrate that formation of focal adhesions is strongly induced by extracellular matrix rigidity, irrespective of arterial or venous origin of endothelial cells.
  
  
  CONCLUSIONS
  Our data show that F-actin-anchored focal adhesions distinguish endothelial phenotypes of human arteries from veins. We conclude that the biomechanical properties of the vascular extracellular matrix determine this endothelial characteristic.
authors.affiliation: From the Department of Molecular Cell Biology, Sanquin Research and Swammerdam Institute for Life Sciences, Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (D.v.G., M.W.J.S., A.-M.D.v.S., P.L.H., S.H.); Department of Plastic and Reconstructive Surgery, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands (L.A.E.W.); and Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (M.J.A.P.D.).
authors.forename: Daphne
authors.initials: D
authors.lastname: van Geemen
authors.affiliation: From the Department of Molecular Cell Biology, Sanquin Research and Swammerdam Institute for Life Sciences, Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (D.v.G., M.W.J.S., A.-M.D.v.S., P.L.H., S.H.); Department of Plastic and Reconstructive Surgery, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands (L.A.E.W.); and Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (M.J.A.P.D.).
authors.forename: Michel W J
authors.initials: MW
authors.lastname: Smeets
authors.affiliation: From the Department of Molecular Cell Biology, Sanquin Research and Swammerdam Institute for Life Sciences, Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (D.v.G., M.W.J.S., A.-M.D.v.S., P.L.H., S.H.); Department of Plastic and Reconstructive Surgery, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands (L.A.E.W.); and Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (M.J.A.P.D.).
authors.forename: Anne-Marieke D
authors.initials: AM
authors.lastname: van Stalborch
authors.affiliation: From the Department of Molecular Cell Biology, Sanquin Research and Swammerdam Institute for Life Sciences, Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (D.v.G., M.W.J.S., A.-M.D.v.S., P.L.H., S.H.); Department of Plastic and Reconstructive Surgery, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands (L.A.E.W.); and Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (M.J.A.P.D.).
authors.forename: Leonie A E
authors.initials: LA
authors.lastname: Woerdeman
authors.affiliation: From the Department of Molecular Cell Biology, Sanquin Research and Swammerdam Institute for Life Sciences, Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (D.v.G., M.W.J.S., A.-M.D.v.S., P.L.H., S.H.); Department of Plastic and Reconstructive Surgery, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands (L.A.E.W.); and Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (M.J.A.P.D.).
authors.forename: Mat J A P
authors.initials: MJ
authors.lastname: Daemen
authors.affiliation: From the Department of Molecular Cell Biology, Sanquin Research and Swammerdam Institute for Life Sciences, Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (D.v.G., M.W.J.S., A.-M.D.v.S., P.L.H., S.H.); Department of Plastic and Reconstructive Surgery, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands (L.A.E.W.); and Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (M.J.A.P.D.).
authors.forename: Peter L
authors.initials: PL
authors.lastname: Hordijk
authors.affiliation: From the Department of Molecular Cell Biology, Sanquin Research and Swammerdam Institute for Life Sciences, Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (D.v.G., M.W.J.S., A.-M.D.v.S., P.L.H., S.H.); Department of Plastic and Reconstructive Surgery, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands (L.A.E.W.); and Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (M.J.A.P.D.). s.huveneers@sanquin.nl.
authors.forename: Stephan
authors.initials: S
authors.lastname: Huveneers
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000199:Actins / Q000032:analysis*; D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D001158:Arteries / Q000166:cytology*; D001940:Breast / Q000098:blood supply; D015820:Cadherins / Q000032:analysis; D002478:Cells, Cultured; D042783:Endothelial Cells; D004730:Endothelium, Vascular / Q000166:cytology*; D019074:Epigastric Arteries / Q000166:cytology; D005109:Extracellular Matrix / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000502:physiology; D005260:Female; D022001:Focal Adhesions; D006801:Humans; D007231:Infant, Newborn; D008638:Mesenteric Arteries / Q000166:cytology; D008642:Mesenteric Veins / Q000166:cytology; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D010641:Phenotype; D014469:Umbilical Arteries / Q000166:cytology; D014471:Umbilical Veins / Q000166:cytology; D014680:Veins / Q000166:cytology*; D000099152:Cadherin 5
chemical_list: D000199:Actins; D015703:Antigens, CD; D015820:Cadherins; D016326:Extracellular Matrix Proteins; D000099152:Cadherin 5
keywords: arteries; focal adhesions