title: Notch signaling functions in retinal pericyte survival.
abstract: OBJECTIVE
  Pericytes, the vascular cells that constitute the outer layer of capillaries, have been shown to have a crucial role in vascular development and stability. Loss of pericytes precedes endothelial cell dysfunction and vascular degeneration in small-vessel diseases, including diabetic retinopathy. Despite their clinical relevance, the cellular pathways controlling survival of retinal pericytes remain largely uncharacterized. Therefore, we investigated the role of Notch signaling, a master regulator of cell fate decisions, in retinal pericyte survival.
  
  
  METHODS
  A coculture system of ligand-dependent Notch signaling was developed using primary cultured retinal pericytes and a mesenchymal cell line derived from an inducible mouse model expressing the Delta-like 1 Notch ligand. This model was used to examine the effect of Notch activity on pericyte survival using quantitative PCR (qPCR) and a light-induced cell death assay. The effect of Notch gain- and loss-of-function was analyzed in monocultures of retinal pericytes using antibody arrays to interrogate the expression of apoptosis-related proteins.
  
  
  RESULTS
  Primary cultured retinal pericytes differentially expressed key molecules of the Notch pathway and displayed strong expression of canonical Notch/RBPJK (recombination signal-binding protein 1 for J-kappa) downstream targets. A gene expression screen using gain- and loss-of-function approaches identified genes relevant to cell survival as downstream targets of Notch activity in retinal pericytes. Ligand-mediated Notch activity protected retinal pericytes from light-induced cell death.
  
  
  CONCLUSIONS
  Our results have identified signature genes downstream of Notch activity in retinal pericytes and suggest that tight regulation of Notch signaling is crucial for pericyte survival.
authors.affiliation: Schepens Eye Research Institute, Mass Eye and Ear Infirmary and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Arboleda-Velasquez
authors.affiliation: Schepens Eye Research Institute, Mass Eye and Ear Infirmary and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Vincent
authors.initials: V
authors.lastname: Primo
authors.affiliation: Schepens Eye Research Institute, Mass Eye and Ear Infirmary and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States University of Exeter Medical School, Exeter, Devon, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Graham
authors.affiliation: Schepens Eye Research Institute, Mass Eye and Ear Infirmary and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States University of Exeter Medical School, Exeter, Devon, United Kingdom.
authors.forename: Alexandra
authors.initials: A
authors.lastname: James
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Jan
authors.initials: J
authors.lastname: Manent
authors.affiliation: Schepens Eye Research Institute, Mass Eye and Ear Infirmary and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: D'Amore
mesh_terms: D000818:Animals; D002417:Cattle; D002470:Cell Survival / Q000502:physiology*; D018920:Coculture Techniques; D059630:Mesenchymal Stem Cells / Q000502:physiology; D023421:Models, Animal; D020286:Pericytes / Q000502:physiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051880:Receptors, Notch / Q000502:physiology*; D012160:Retina / Q000166:cytology* / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D011518:Proto-Oncogene Proteins; D051880:Receptors, Notch
keywords: coculture; diabetic retinopathy; notch signaling; pericyte; small-vessel; survival