This study seeks to determine the mechanisms of intense light-mediated photoreceptor cell degeneration. The hypotheses to be tested are: (1) that there is a sensitive period within the circadian cycle which results in enhanced susceptibility to retinal light damage and which is mediated by the expression of intrinsic factors in the retina (aim 1) and (2) that susceptibility to light damage is affected by genetic inheritance, which can enhance the rate of photoreceptor cell loss from environmental insult in the form of dim cyclic light exposure or acute intense light treatment (aim 2). This proposal will focus on identifying the circadian expression of intrinsic factors in the retina that enhance or prevent light-induced cell damage leading to apoptotic cell death. The investigator will study the interactions of light-and dark rearing conditions and the timing of intense light treatments in vivo that produce synchronous photoreceptor cell damage in normal albino rats and in transgenic rats with mutations in the rhodopsin primary amino acid sequence. Photoreceptor cell loss will be assayed using rhodopsin and photoreceptor DNA measurements, electrophoretic analysis of DNA fragmentation, and light and electron microscopy of light-damaged retinas. The circadian expression of melatonin and dopamine will be measured and Western and Northern analysis will be used to identify potential modulators of retinal damage. These measurements will be complimented by 2D gel electrophoresis of retinal proteins and ordered differential display of mRNA from retinas at different times of the day and night. The synthetic antioxidant dimethylthiourea will be used as a probe to uncover early events in the mechanism of cell death, including mitochondrial involvement and the potential for oxidative stress to induce apoptosis. In addition, the time course of the appearance of cytoplasmic cytochrome C and the activation of cellular caspases will be determined by antibody-based techniques, immunocytochemistry and enzymatic analysis.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY001959-27
Application #
6635546
Study Section
Visual Sciences C Study Section (VISC)
Program Officer
Dudley, Peter A
Project Start
1977-04-01
Project End
2005-03-31
Budget Start
2003-04-01
Budget End
2005-03-31
Support Year
27
Fiscal Year
2003
Total Cost
$312,484
Indirect Cost
Name
Wright State University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
047814256
City
Dayton
State
OH
Country
United States
Zip Code
45435
Organisciak, Daniel; Darrow, Ruth; Barsalou, Linda et al. (2011) Light induced and circadian effects on retinal photoreceptor cell crystallins. Photochem Photobiol 87:151-9
Organisciak, Daniel T; Vaughan, Dana K (2010) Retinal light damage: mechanisms and protection. Prog Retin Eye Res 29:113-34
Marc, Robert E; Jones, B W; Watt, C B et al. (2008) Extreme retinal remodeling triggered by light damage: implications for age related macular degeneration. Mol Vis 14:782-806
Organisciak, Daniel; Darrow, Ruth; Gu, Xiaorong et al. (2006) Genetic, age and light mediated effects on crystallin protein expression in the retina. Photochem Photobiol 82:1088-96
Duncan, Todd; Wiggert, Barbara; Whittaker, Noel et al. (2006) Effect of visible light on normal and P23H-3 transgenic rat retinas: characterization of a novel retinoic acid derivative present in the P23H-3 retina. Photochem Photobiol 82:741-5
Grewal, Ruby; Organisciak, Daniel; Wong, Paul (2006) Factors underlying circadian dependent susceptibility to light induced retinal damage. Adv Exp Med Biol 572:411-6
Palamalai, Vikram; Darrow, Ruth M; Organisciak, Daniel T et al. (2006) Light-induced changes in protein nitration in photoreceptor rod outer segments. Mol Vis 12:1543-51
Sun, Mingjiang; Finnemann, Silvia C; Febbraio, Maria et al. (2006) Light-induced oxidation of photoreceptor outer segment phospholipids generates ligands for CD36-mediated phagocytosis by retinal pigment epithelium: a potential mechanism for modulating outer segment phagocytosis under oxidant stress conditions. J Biol Chem 281:4222-30
Ablonczy, Z; Darrow, R M; Knapp, D R et al. (2005) Rhodopsin phosphorylation in rats exposed to intense light. Photochem Photobiol 81:541-7
Jomary, Catherine; Darrow, Ruth M; Wong, Paul et al. (2004) Expression of neurturin, glial cell line-derived neurotrophic factor, and their receptor components in light-induced retinal degeneration. Invest Ophthalmol Vis Sci 45:1240-6

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