While a number of genes have been postulated to be involved in age-related macular degeneration (AMD), the leading cause of blindness among the elderly in the US, a comprehensive mRNA phenotype of the retinal pigment epithelium (RPE) in vivo is at present unknown. Determination of an RPE mRNA phenotype could identify the genes critical to the development of AMD, identify markers of disease, and lead to new preventative and treatment strategies. Basal deposits in Bruch's membrane are an early recognizable change that occur prior to degeneration of the RPE and are a histopathological marker for AMD. Recently, our laboratory identified an age-dependent accumulation of advanced glycation end products (AGEs) in Bruch's membrane and basal deposits. AGEs are structures formed during the series of nonenzymatic reactions between sugars or other precursors, and long-lived proteins that alter the phenotype of a variety of cell types. Our laboratory has also recently shown that AGEs alter the expression of genes involved in matrix regulation, cell polarity, and apoptosis in RPE cells. Our long term goal is to define an extensive mRNA phenotype of the RPE in health and AMD which will in turn, yield insights into the pathogenesis of AMD. Specifically, we want to define the component of that phenotype which is regulated by AGEs. We hypothesize that the presence of AGEs in basal deposits is responsible for a switch in the phenotype of RPE cells that is consistent with alterations in matrix regulation, RPE cell polarity, and apoptosis. To test this hypothesis we ask 3 questions: 1. Are the mRNA phenotypes of macular RPE cells overlying basal deposits and normal Bruch's membrane different? 2. Does AGE modified matrix induce an RPE mRNA phenotype in vitro that is a subset of the phenotype expressed by RPE cells overlying basal deposits? 3. Is a subset of the AGE induced mRNA phenotype of RPE cells mediated by the Receptor for Advanced Glycation End products? To answer these questions we will use laser capture microdissection to obtain pure samples of RPE cells from tissue specimens for mRNA phenotyping by microarray analysis. We will also utilize an in vitro AGE-matrix system to determine what subset of genes is regulated by AGEs. This project hopes to establish an extensive mRNA phenotype of the RPE in both health and AMD, and define a subset of genes induced by AGEs.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
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Visual Sciences C Study Section (VISC)
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Mariani, Andrew P
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Johns Hopkins University
Schools of Medicine
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Datta, Sayantan; Cano, Marisol; Ebrahimi, Katayoon et al. (2017) The impact of oxidative stress and inflammation on RPE degeneration in non-neovascular AMD. Prog Retin Eye Res 60:201-218
Wang, Lei; Ebrahimi, Katayoon B; Chyn, Michelle et al. (2016) Biology of p62/sequestosome-1 in Age-Related Macular Degeneration (AMD). Adv Exp Med Biol 854:17-22
Wang, Lei; Cano, Marisol; Datta, Sayantan et al. (2016) Pentraxin 3 recruits complement factor H to protect against oxidative stress-induced complement and inflammasome overactivation. J Pathol 240:495-506
Wei, Hong; Xun, Zixian; Granado, Herta et al. (2016) An easy, rapid method to isolate RPE cell protein from the mouse eye. Exp Eye Res 145:450-455
Sinha, Debasish; Valapala, Mallika; Shang, Peng et al. (2016) Lysosomes: Regulators of autophagy in the retinal pigmented epithelium. Exp Eye Res 144:46-53
Handa, James T; Tagami, Mizuki; Ebrahimi, Katayoon et al. (2015) Lipoprotein(A) with An Intact Lysine Binding Site Protects the Retina From an Age-Related Macular Degeneration Phenotype in Mice (An American Ophthalmological Society Thesis). Trans Am Ophthalmol Soc 113:T5
Wang, Lei; Cano, Marisol; Handa, James T (2014) p62 provides dual cytoprotection against oxidative stress in the retinal pigment epithelium. Biochim Biophys Acta 1843:1248-58
Fujihara, Masashi; Cano, Marisol; Handa, James T (2014) Mice that produce ApoB100 lipoproteins in the RPE do not develop drusen yet are still a valuable experimental system. Invest Ophthalmol Vis Sci 55:7285-95
Ebrahimi, Katayoon B; Fijalkowski, Natalia; Cano, Marisol et al. (2014) Oxidized low-density-lipoprotein-induced injury in retinal pigment epithelium alters expression of the membrane complement regulatory factors CD46 and CD59 through exosomal and apoptotic bleb release. Adv Exp Med Biol 801:259-65
Sachdeva, Mira M; Cano, Marisol; Handa, James T (2014) Nrf2 signaling is impaired in the aging RPE given an oxidative insult. Exp Eye Res 119:111-4

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