title: Mechanisms underlying AQP4 accumulation in astrocyte endfeet.
abstract: The brain-blood interface holds the key to our understanding of how cerebral blood flow is regulated and how water and solutes are exchanged between blood and brain. The highly specialized astrocytic membranes that enwrap brain microvessels are salient constituents of the brain-blood interface. These endfoot membranes contain a distinct set of molecules that is anchored to the subendothelial basal lamina forming an endfoot-basal lamina junctional complex. Here we explore the mechanisms underpinning the formation of this complex. By use of a tailor made model system we show that endothelial cells promote AQP4 accumulation by exerting an inductive effect through extracellular matrix components such as agrin, as well as through a direct mechanical interaction with the endfoot processes. Through the compounds they secrete, the endothelial cells also increase AQP4 expression. The present data suggest that the highly specialized gliovascular interface is established through inductive processes that include both chemical and mechanical factors. GLIA 2015;63:2073-2091.
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway.
authors.forename: Laura Maria Azzurra
authors.initials: LMA
authors.lastname: Camassa
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway.
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Lunde
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway.
authors.forename: Eystein H
authors.initials: EH
authors.lastname: Hoddevik
authors.affiliation: Laboratory of Proteomic Research, Department of Immunology, University of Oslo, Norway.
authors.forename: Maria
authors.initials: M
authors.lastname: Stensland
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway.
authors.forename: Henning B
authors.initials: HB
authors.lastname: Boldt
authors.affiliation: Laboratory of Proteomic Research, Department of Immunology, University of Oslo, Norway.
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: De Souza
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway.
authors.forename: Ole P
authors.initials: OP
authors.lastname: Ottersen
authors.affiliation: Laboratory of Molecular Neuroscience, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Amiry-Moghaddam
keywords: agrin; aquaporin; astroglia; compartmentalization; extracellular matrix; polarization