title: Increased expression of glial cell line-derived neurotrophic factor protects against oxidative damage-induced retinal degeneration.
abstract: Oxidative damage contributes to retinal cell death in patients with age-related macular degeneration or retinitis pigmentosa. One approach to treatment is to identify and eliminate the sources of oxidative damage. Another approach is to identify treatments that protect cells from multiple sources of oxidative damage. In this study, we investigated the effect of increased expression of glial cell line-derived neurotrophic factor (GDNF) in three models of oxidative damage-induced retinal degeneration. Double transgenic mice with doxycycline-inducible expression of GDNF in the retina were exposed to paraquat, FeSO(4), or hyperoxia, all sources of oxidative damage and retinal cell death. Compared to controls, mice with increased expression of GDNF in the retina showed significant preservation of retinal function measured by electroretinograms, reduced thinning of retinal cell layers, and fewer TUNEL-positive cells indicating less retinal cell death. Mice over-expressing GDNF also showed less staining for acrolein, nitrotyrosine, and 8-hydroxydeoxyguanosine, indicating less oxidative damage to lipids, proteins, and DNA. This suggests that GDNF did not act solely to allow cells to tolerate higher levels of oxidative damage before initiation of apoptosis, but also reduced damage from oxidative stress to critical macromolecules. These data suggest that gene transfer of Gdnf should be considered as a component of therapy for retinal degenerations in which oxidative damage plays a role.
authors.affiliation: Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA.
authors.forename: Aling
authors.initials: A
authors.lastname: Dong
authors.forename: JiKui
authors.initials: J
authors.lastname: Shen
authors.forename: Melissa
authors.initials: M
authors.lastname: Krause
authors.forename: Sean F
authors.initials: SF
authors.lastname: Hackett
authors.forename: Peter A
authors.initials: PA
authors.lastname: Campochiaro
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D019610:Cytoprotection / Q000235:genetics*; D004249:DNA Damage / Q000502:physiology; D004596:Electroretinography; D005290:Ferric Compounds / Q000633:toxicity; D015870:Gene Expression / Q000502:physiology; D015316:Genetic Therapy / Q000379:methods; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D006540:Herbicides / Q000633:toxicity; D018496:Hyperoxia / Q000150:complications / Q000503:physiopathology; D015227:Lipid Peroxidation / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D010100:Oxygen / Q000633:toxicity; D010269:Paraquat / Q000633:toxicity; D011506:Proteins / Q000378:metabolism; D012162:Retinal Degeneration / Q000378:metabolism* / Q000503:physiopathology; D015854:Up-Regulation / Q000502:physiology
chemical_list: D005290:Ferric Compounds; D051100:Glial Cell Line-Derived Neurotrophic Factor; D006540:Herbicides; D011506:Proteins; C024823:ferric sulfate; D010269:Paraquat; D010100:Oxygen