Impact of Lipofuscin in Retinal Pigment Epithelial Cells

脂褐素对视网膜色素上皮细胞的影响

基本信息

批准号：
10211430
负责人：
Janet Ruthe Sparrow
金额：
$ 40.5万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-05-01 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10211430
关键词：
11 cis Retinal Abbreviations Acute Address Age related macular degeneration Aldehydes All-Trans-Retinol American Biochemical Bolus Infusion Cellular Assay Clinical Complex Mixtures Darkness Deposition Diagnosis Diet Disease Equilibrium Family Fundus Gene Deletion Genetic Genotype Glyoxal Health High Fat Diet High Pressure Liquid Chromatography Histologic Image Injections Intake International Unit Investigation Kinetics Lasers Lead Legal Blindness Light Link Lipids Lipofuscin Liquid Chromatography Measurement Measures Medical Genetics Membrane Metabolism Methods Modeling Monitor Mus Mutation Nuclear Obese Mice Obesity Ophthalmoscopy Overweight Pathogenicity Patients Performance Periodicity Pharmacotherapy Phenotype Phosphatidylethanolamine Photoreceptors Population Prevalence Process Proteins Public Health Pyruvaldehyde Quantitative Reverse Transcriptase PCR RBP4 gene Reactive Oxygen Species Research Retina Retinal Degeneration Retinal Diseases Retinaldehyde Retinitis Pigmentosa Retinoids Reverse Transcriptase Polymerase Chain Reaction Risk Role Scanning Serum Source Spectrometry, Mass, Electrospray Ionization Stargardt&apos s disease Structure of retinal pigment epithelium Supplementation Testing Time Toxic effect Vitamin A Weight Weights and Measures Work adduct clinical Diagnosis confocal imaging diet-induced obesity disease natural history experimental study fluorophore fundus imaging genetic testing human subject lipid metabolism macromolecule novel overweight adults visual cycle

项目摘要

Project Summary/Abstract The prevalence of obesity in the US population is a growing health risk. We have observed that in high fat diet- induced obese (DIO) mice, vitamin A aldehyde adducts (bisretinoids) accumulate at elevated levels. Bisretinoids constitute the complex mixture of visual cycle adducts that form randomly in photoreceptor outer segments due to non-enzymatic reactions of retinaldehyde. These fluorophores are deposited in retinal pigment epithelial cells as components of phagocytosed outer segment membrane and constitute the lipofuscin of retina. It is well known that bisretinoid formation is modulated by the availability of vitamin A (i.e. visual cycle kinetics). The toxicity of this family of bisretinoids is attributable, at least in part, to their propensity to photogenerate reactive oxygen species and photodecompose into dicarbonyl- (glyoxal, GO; methylglyoxal, MG) and aldehyde-bearing fragments. The broad objectives of the studies proposed in this application are to explore links between the formation of toxic bisretinoids and dysregulation of vitamin A in association with obesity. Experiments proposed in Specific Aim 1 will undertake the novel exploration of relationships amongst a high fat diet, vitamin A, retinol binding protein 4 (Rbp4) and augmented bisretinoid in retina. Our working model is that increased delivery of vitamin A (retinol) to RPE under these conditions involves both Rbp4 and non-Rbp4 mechanisms. In mice fed a high fat diet and in obese ob/ob mice we will measure ocular levels of retinoid and bisretinoid and we will employ quantitative fundus autofluorescence imaging (qAF) for non-invasive measurement of bisretinoid. The role of RBP4 will be tested in mice by measuring serum Rbp4 and by studying mice deficient in Rbp4-/- due to gene deletion and drug treatment. Photoreceptor cell health will be evaluated by histometric analysis of outer nuclear layer. In the studies described in Specific Aim 2, we will address human subjects having excess weight by measuring bisretinoids using non-invasive quantitative fundus autofluorescence (qAF). In experiments presented in Specific Aim 3 we will challenge existing notions as to the conditions that govern the the extent of bisretinoid formation, the loss of bisretinoid due to photooxidation and factors determining the topographic distribution of SW-AF. To this end, we will quantify the relationship between vitamin A intake and bisretinoid formation. We will measure loss of bisretinoid by comparing levels in mice reared in darkness versus cyclic light. Bisretinoid lipofuscin will be measured chromatographically and by non-invasive qAF. The work will employ fundus imaging and biochemical, histological and cellular assays. Completion of this research will advance our understanding of previously unrecognized links amongst obesity, vitamin A metabolism and bisretinoid fluorophores.

项目概要/摘要肥胖在美国人口中的流行是一个日益严重的健康风险。我们观察到，在高脂肪饮食中—— 在诱导性肥胖 (DIO) 小鼠中，维生素 A 醛加合物（双维A酸）的积累水平升高。双维A酸类构成视觉周期加合物的复杂混合物，由于在感光器外节中随机形成视黄醛的非酶促反应。这些荧光团沉积在视网膜色素上皮细胞中作为吞噬外节膜的成分并构成视网膜的脂褐质。众所周知双视黄醇的形成受维生素 A 的可用性（即视觉循环动力学）的调节。毒性这个双维A酸家族至少部分归因于它们光产生活性氧的倾向物质并光分解成二羰基（乙二醛，GO；甲基乙二醛，MG）和含醛的碎片。本申请中提出的研究的主要目标是探索形成之间的联系有毒的双维A酸和与肥胖相关的维生素A失调。具体中提出的实验目标 1 将对高脂肪饮食、维生素 A、视黄醇结合之间的关系进行新颖的探索视网膜中的蛋白 4 (Rbp4) 和增强型双维A酸。我们的工作模式是增加维生素 A 的输送在这些条件下（视黄醇）到 RPE 涉及 Rbp4 和非 Rbp4 机制。在喂食高脂肪的小鼠中我们将测量饮食中的类维生素A和双类维生素A的眼部水平，并在肥胖的ob/ob小鼠中使用用于双维A酸无创测量的定量眼底自发荧光成像（qAF）。的作用将通过测量血清 Rbp4 并研究因基因而缺乏 Rbp4-/- 的小鼠来测试 RBP4 删除和药物治疗。将通过外核的组织计量分析来评估感光细胞的健康状况层。在具体目标 2 中描述的研究中，我们将通过以下方式解决超重的人类受试者问题：使用非侵入性定量眼底自发荧光 (qAF) 测量双维A酸。在实验中提出在具体目标 3 中，我们将挑战关于控制双维A酸范围的条件的现有观念形成、光氧化导致的双维A酸损失以及决定其地形分布的因素 SW-AF。为此，我们将量化维生素 A 摄入量与双维A酸形成之间的关系。我们将通过比较在黑暗和循环光中饲养的小鼠的水平来测量双维A酸的损失。双维A酸脂褐素将通过色谱法和非侵入性 qAF 进行测量。这项工作将采用眼底成像以及生化、组织学和细胞测定。完成这项研究将加深我们对肥胖、维生素 A 代谢和双维A酸荧光团之间以前未被认识到的联系。