title: Hyperactivation of retina by light in mice leads to photoreceptor cell death mediated by VEGF and retinal pigment epithelium permeability.
abstract: Light toxicity is suspected to enhance certain retinal degenerative processes such as age-related macular degeneration. Death of photoreceptors can be induced by their exposure to the visible light, and although cellular processes within photoreceptors have been characterized extensively, the role of the retinal pigment epithelium (RPE) in this model is less well understood. We demonstrate that exposition to intense light causes the immediate breakdown of the outer blood-retinal barrier (BRB). In a molecular level, we observed the slackening of adherens junctions tying up the RPE and massive leakage of albumin into the neural retina. Retinal pigment epithelial cells normally secrete vascular endothelial growth factor (VEGF) at their basolateral side; light damage in contrast leads to VEGF increase on the apical side--that is, in the neuroretina. Blocking VEGF, by means of lentiviral gene transfer to express an anti-VEGF antibody in RPE cells, inhibits outer BRB breakdown and retinal degeneration, as illustrated by functional, behavioral and morphometric analysis. Our data show that exposure to high levels of visible light induces hyperpermeability of the RPE, likely involving VEGF signaling. The resulting retinal edema contributes to irreversible damage to photoreceptors. These data suggest that anti-VEGF compounds are of therapeutic interest when the outer BRB is altered by retinal stresses.
authors.affiliation: Unit of Gene Therapy & Stem Cell Biology, Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Cachafeiro
authors.forename: A P
authors.initials: AP
authors.lastname: Bemelmans
authors.forename: M
authors.initials: M
authors.lastname: Samardzija
authors.forename: T
authors.initials: T
authors.lastname: Afanasieva
authors.forename: J A
authors.initials: JA
authors.lastname: Pournaras
authors.forename: C
authors.initials: C
authors.lastname: Grimm
authors.forename: C
authors.initials: C
authors.lastname: Kostic
authors.forename: S
authors.initials: S
authors.lastname: Philippe
authors.forename: A
authors.initials: A
authors.lastname: Wenzel
authors.forename: Y
authors.initials: Y
authors.lastname: Arsenijevic
mesh_terms: D000418:Albumins / Q000378:metabolism; D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D004195:Disease Models, Animal; D008027:Light; D051379:Mice; D008807:Mice, Inbred BALB C; D018696:Neuroprotective Agents / Q000494:pharmacology; D010539:Permeability / Q000187:drug effects / Q000528:radiation effects; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects / Q000378:metabolism / Q000473:pathology* / Q000528:radiation effects; D055213:Retinal Pigment Epithelium / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects*; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000418:Albumins; D018696:Neuroprotective Agents; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2; D019061:src-Family Kinases