title: Cell-cell junctions of dermal microvascular endothelial cells contain tight and adherens junction proteins in spatial proximity.
abstract: Endothelial cell-cell contacts control the vascular permeability, thereby regulating the flow of solutes, macromolecules, and leukocytes between blood vessels and interstitial space. Because of specific needs, the endothelial permeability differs significantly between the tight blood-brain barrier endothelium and the more permeable endothelial lining of the non-brain microvasculature. Most likely, such differences are due to a differing architecture of the respective interendothelial cell contacts. However, while the molecules and junctional complexes of macrovascular endothelial cells and the blood-brain barrier endothelium are fairly well characterized, much less is known about the organization of intercellular contacts of microvascular endothelium. Toward this end, we developed a combined cross-linking and immunoprecipitation protocol which enabled us to map nearest neighbor interactions of junctional proteins in the human dermal microvascular endothelial cell line HMEC-1. We show that proteins typically located in tight or adherens junctions of epithelial cells are in the proximity in HMEC-1 cells. This contrasts with the separation of the different types of junctions observed in polarized epithelial cells and "tight" endothelial layers of the blood-brain barrier and argues for a need of the specific junctional contacts in microvascular endothelium possibly required to support an efficient transendothelial migration of leukocytes.
authors.affiliation: Institute of Medical Biochemistry, Center for Molecular Biology of Inflammation, University of Muenster, von-Esmarch-Strasse 56, D-48149 Muenster, Germany.
authors.forename: Claas
authors.initials: C
authors.lastname: Rüffer
authors.forename: Anke
authors.initials: A
authors.lastname: Strey
authors.forename: Annette
authors.initials: A
authors.lastname: Janning
authors.forename: Kwang Sik
authors.initials: KS
authors.lastname: Kim
authors.forename: Volker
authors.initials: V
authors.lastname: Gerke
mesh_terms: D022005:Adherens Junctions / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD; D001921:Brain / Q000166:cytology / Q000378:metabolism; D015820:Cadherins; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology*; D002460:Cell Line; D003432:Cross-Linking Reagents / Q000378:metabolism; D004285:Dogs; D004730:Endothelium, Vascular / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008833:Microcirculation / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011233:Precipitin Tests; D012867:Skin / Q000098:blood supply / Q000737:chemistry* / Q000378:metabolism; D019108:Tight Junctions / Q000737:chemistry* / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
chemical_list: D015703:Antigens, CD; C050361:CDH2 protein, human; D015820:Cadherins; D015815:Cell Adhesion Molecules; D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D010750:Phosphoproteins; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein