title: Reduction of p66Shc suppresses oxidative damage in retinal pigmented epithelial cells and retina.
abstract: The largest isoform of the Shc adapter protein, p66Shc, has been implicated in oxidative damage-induced apoptosis in vital organs, because mice deficient in p66Shc have a 30% increase in life span and are resistant to the lethal effects of systemically administered paraquat, a source of severe oxidative damage. In this study, we utilized siRNA directed against the CH2 domain of Shc, to reduce p66Shc, but not p52Shc nor p46Shc in retinal pigmented epithelial (RPE) cells. RPE cells deficient in p66Shc had reduced susceptibility to oxidative stress-induced apoptosis. Compared to control cells, those with reduced p66Shc had increased basal and oxidative stress-induced NF-kappaB transcriptional activity, increased levels of antioxidant enzymes, and less generation of reactive oxygen species when challenged with H(2)O(2). The increase in oxidative stress-induced NF-kappaB activity was mediated by activation of ERK. Compared to eyes injected with GFP siRNA, those injected with p66Shc siRNA showed less loss of retinal function as assessed by electroretinograms from paraquat-induced oxidative stress. These data suggest that p66Shc and molecular signals involved in its regulation provide therapeutic targets for retinal degenerations in which oxidative-damage plays a major role, including age-related macular degeneration and cone cell death in retinitis pigmentosa.
authors.affiliation: Departments of Ophthalmology and Neuroscience, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Wu
authors.forename: Brian
authors.initials: B
authors.lastname: Rogers
authors.forename: Shu
authors.initials: S
authors.lastname: Kachi
authors.forename: Sean F
authors.initials: SF
authors.lastname: Hackett
authors.forename: Anna
authors.initials: A
authors.lastname: Sick
authors.forename: Peter A
authors.initials: PA
authors.lastname: Campochiaro
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology; D004596:Electroretinography; D004791:Enzyme Inhibitors / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D006540:Herbicides / Q000633:toxicity; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress; D010269:Paraquat / Q000633:toxicity; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000975:Antioxidants; D004791:Enzyme Inhibitors; D006540:Herbicides; D016328:NF-kappa B; D016877:Oxidants; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D006861:Hydrogen Peroxide; D048049:Extracellular Signal-Regulated MAP Kinases; D010269:Paraquat