title: Plasmalemma Vesicle-Associated Protein Has a Key Role in Blood-Retinal Barrier Loss.
abstract: Loss of blood-retinal barrier (BRB) properties induced by vascular endothelial growth factor (VEGF) and other factors is an important cause of diabetic macular edema. Previously, we found that the presence of plasmalemma vesicle-associated protein (PLVAP) in retinal capillaries associates with loss of BRB properties and correlates with increased vascular permeability in diabetic macular edema. In this study, we investigated whether absence of PLVAP protects the BRB from VEGF-induced permeability. We used lentiviral-delivered shRNA or siRNA to inhibit PLVAP expression. The barrier properties of in vitro BRB models were assessed by measuring transendothelial electrical resistance, permeability of differently sized tracers, and the presence of endothelial junction complexes. The effect of VEGF on caveolae formation was studied in human retinal explants. BRB loss in vivo was studied in the mouse oxygen-induced retinopathy model. The inhibition of PLVAP expression resulted in decreased VEGF-induced BRB permeability of fluorescent tracers, both in vivo and in vitro. PLVAP inhibition attenuated transendothelial electrical resistance reduction induced by VEGF in BRB models in vitro and significantly increased transendothelial electrical resistance of the nonbarrier human umbilical vein endothelial cells. Furthermore, PLVAP knockdown prevented VEGF-induced caveolae formation in retinal explants but did not rescue VEGF-induced alterations in endothelial junction complexes. In conclusion, PLVAP is an essential cofactor in VEGF-induced BRB permeability and may become an interesting novel target for diabetic macular edema therapy.
authors.affiliation: Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Joanna
authors.initials: J
authors.lastname: Wisniewska-Kruk
authors.affiliation: Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Anne-Eva
authors.initials: AE
authors.lastname: van der Wijk
authors.affiliation: Core Facility Cellular Imaging, Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Henk A
authors.initials: HA
authors.lastname: van Veen
authors.affiliation: University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Theo G M F
authors.initials: TG
authors.lastname: Gorgels
authors.affiliation: Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Ilse M C
authors.initials: IM
authors.lastname: Vogels
authors.affiliation: Hubrecht Laboratory and Interuniversity Cardiology Institute Netherlands, Royal Netherlands Academy of Arts and Sciences, Utrecht, the Netherlands.
authors.forename: Danielle
authors.initials: D
authors.lastname: Versteeg
authors.affiliation: Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands; Core Facility Cellular Imaging, Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Cornelis J F
authors.initials: CJ
authors.lastname: Van Noorden
authors.affiliation: Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Reinier O
authors.initials: RO
authors.lastname: Schlingemann
authors.affiliation: Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands. Electronic address: i.klaassen@amc.uva.nl.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Klaassen
mesh_terms: D000818:Animals; D001813:Blood-Retinal Barrier / Q000378:metabolism*; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology*; D003930:Diabetic Retinopathy / Q000378:metabolism*; D004195:Disease Models, Animal; D006801:Humans; D008269:Macular Edema / Q000378:metabolism / Q000473:pathology; D051379:Mice; D051381:Rats; D012160:Retina / Q000378:metabolism*; D012171:Retinal Vessels / Q000378:metabolism* / Q000648:ultrastructure*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D042461:Vascular Endothelial Growth Factor A