title: Oxidative stress in retinal pigment epithelium cells increases exosome secretion and promotes angiogenesis in endothelial cells.
abstract: The retinal pigment epithelium (RPE), a monolayer located between the photoreceptors and the choroid, is constantly damaged by oxidative stress, particularly because of reactive oxygen species (ROS). As the RPE, because of its physiological functions, is essential for the survival of the retina, any sustained damage may consequently lead to loss of vision. Exosomes are small membranous vesicles released into the extracellular medium by numerous cell types, including RPE cells. Their cargo includes genetic material and proteins, making these vesicles essential for cell-to-cell communication. Exosomes may fuse with neighbouring cells influencing their fate. It has been observed that RPE cells release higher amounts of exosomes when they are under oxidative stress. Exosomes derived from cultured RPE cells were isolated by ultracentrifugation and quantified by flow cytometry. VEGF receptors (VEGFR) were analysed by both flow cytometry and Western blot. RT-PCR and qPCR were conducted to assess mRNA content of VEGFRs in exosomes. Neovascularization assays were performed after applying RPE exosomes into endothelial cell cultures. Our results showed that stressed RPE cells released a higher amount of exosomes than controls, with a higher expression of VEGFR in the membrane, and enclosed an extra cargo of VEGFR mRNA. Angiogenesis assays confirmed that endothelial cells increased their tube formation capacity when exposed to stressed RPE exosomes.
authors.affiliation: School of Medicine, Catholic University of Valencia, Valencia, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Atienzar-Aroca
authors.affiliation: School of Medicine, Catholic University of Valencia, Valencia, Spain.|Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Miguel
authors.initials: M
authors.lastname: Flores-Bellver
authors.affiliation: Experimental Research Unit, General University Hospital of Albacete, Albacete, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Serrano-Heras
authors.affiliation: School of Medicine, Catholic University of Valencia, Valencia, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Martinez-Gil
authors.affiliation: School of Medicine, Catholic University of Valencia, Valencia, Spain.
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Barcia
authors.affiliation: Valencian Biomedicine Institute CSIC, Valencia, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Aparicio
authors.affiliation: Department of Physiology, University of Valencia, Valencia, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Perez-Cremades
authors.affiliation: Department of Comparative Neurobiology, Cavanilles Institute of Biodiversity and Evolutive Biology, University of Valencia, Paterna, Valencia, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Garcia-Verdugo
authors.affiliation: Department of Surgery, University of Valencia, Valencia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Diaz-Llopis
authors.affiliation: School of Medicine, Catholic University of Valencia, Valencia, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Romero
authors.affiliation: School of Medicine, Catholic University of Valencia, Valencia, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Sancho-Pelluz
mesh_terms: D002460:Cell Line; D000431:Ethanol / Q000494:pharmacology; D055354:Exosomes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D018919:Neovascularization, Physiologic / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000473:pathology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D000431:Ethanol; D040262:Receptors, Vascular Endothelial Growth Factor
keywords: VEGF receptors; angiogenesis; exosomes; oxidative stress; retinal pigment epithelium