Lipid Trafficking and Metabolism in the Retinal Pigment Epithelium

视网膜色素上皮中的脂质运输和代谢

基本信息

批准号：
10350995
负责人：
Jason Matthew-Lewis Miller
金额：
$ 24.01万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-03-01 至 2027-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10350995
关键词：
Age related macular degeneration Apical Award Basic Science Biochemical Biology Blindness Cell Nucleus Cell Respiration Cells Characteristics Choroid Consumption Data Deposition Development Plans Disease Drusen Endoplasmic Reticulum Ensure Enzymes Equilibrium FDA approved Foundations Glucose Goals Health Homeostasis Human Impairment Ingestion Label Lipase Lipid Mobilization Lipid Peroxidation Lipids Lipoproteins Lysosomes Mass Spectrum Analysis Mechanics Mediating Mentors Mentorship Metabolic Metabolism Methods Michigan Microscopy Mitochondria Modeling Monitor Morbidity - disease rate Natural regeneration Nonesterified Fatty Acids Nonexudative age-related macular degeneration Organelles Pathologic Pathway interactions Phagocytosis Pharmacology Photoreceptors Physiological Physiology Play Principal Investigator Process Radiolabeled Reporter Research Research Personnel Resolution Retina Retinal Degeneration Retinal Diseases Role Small Interfering RNA Structure of retinal pigment epithelium Testing Tracer Universities career career development cell type cholesterol analog choroidal circulation experience extracellular flexibility improved induced pluripotent stem cell lipid metabolism lipid transport lipidomics mitochondrial metabolism novel novel therapeutics oxidation oxidative damage particle prevent programs response retinal progenitor cell small molecule uptake visual cycle

项目摘要

SUMMARY: Age-related macular degeneration (AMD) is marked by retinal pigment epithelial (RPE) lipid dys- homeostasis, including pathologic extracellular lipid accumulation, impaired mitochondrial lipid metabolism, and increased lipid peroxidation, a toxic form of lipid oxidative damage. The RPE normally plays an essential role in retinal lipid homeostasis, consuming and secreting prodigious amounts of lipid. Lipid consumption comes in the form of a large daily lipid load, including both lipoprotein uptake from the choroid and phagocytosis of lipid-rich photoreceptor outer segments (OS). Some of this lipid is oxidatively metabolized in the mitochondria, producing metabolites that energetically support photoreceptors. Lipid oxidative metabolism also minimizes glucose use by the RPE, allowing glucose to pass unused from the choroid to highly glycolytic photoreceptors. Lipid secretion is primarily through lipoprotein, some of which supports regeneration of OS and some of which accumulates as the extracellular deposits typical of AMD. A characteristic of cells facing large lipid loads is the formation of lipid droplets (LD), intracellular lipid storage organelles that dynamically regulate lipid trafficking, metabolism, and lipid peroxidation. Specific LD function varies widely between different cell types. RPE LD have been studied in the context of visual cycle biology, but their physiology and role in maintaining non-retinoid lipid homeostasis in the RPE is essentially unexplored. This proposal examines the composition, physiology, and role of LD in human RPE lipid homeostasis. The over-arching hypothesis is two-fold: a) LD can temporarily store a wide-range of lipids derived from the RPE’s daily lipid load, preventing their lipid peroxidation; and b) lipid released from LD by specific enzymes is preferentially metabolized in mitochondria rather than secreted. By facilitating lipid oxidative metabolism over lipid secretion, RPE LD may enhance metabolic support for photoreceptors and decrease the accumulation of pathologic extracellular lipid seen in AMD. To test the hypothesis, various lipid loads will be fed to primary- and induced pluripotent stem cell (iPSC)-derived human RPE cultures, with LD composition assessed by mass spectrometry. The fate of lipids released from LD will be tracked via microscopy, biochemical methods, and lipidomics. The principal investigator’s long-term goal is to develop the expertise to define intracellular RPE lipid trafficking pathways that enhance RPE lipid homeostasis and decrease pathologic extracellular lipid deposition, opening up new therapeutic avenues for AMD. To achieve this goal, the principal investigator’s career development plan (CDP) focuses on RPE lipid biology, establishing expertise in iPSC-RPE culture, radiolabeled lipid tracing, high-resolution microscopy, bio-energetic profiling, and lipidomics. The CDP’s mentorship team takes advantage of deep expertise in lipid biology and lipidomics at University of Michigan and has a track-record of successfully mentoring K awardees to research independence. The combination of didactics and hands-on experience in this proposal ensures the investigator will become a successful AMD- focused clinician with an independent basic science program harnessing RPE lipid biology to understand AMD.

摘要：年龄相关性黄斑变性（AMD）的特点是视网膜色素上皮（RPE）脂质异常。稳态，包括病理性细胞外脂质积累、线粒体脂质代谢受损，以及脂质过氧化增加，脂质氧化损伤的一种有毒形式，RPE 通常在其中发挥重要作用。视网膜脂质稳态，消耗和分泌大量脂质。每日大量脂质负荷的形式，包括从脉络膜摄取脂蛋白和富含脂质的吞噬作用光感受器外节（OS）中的一些脂质在线粒体中氧化代谢，产生。大力支持光感受器的代谢物也最大限度地减少了葡萄糖的使用。通过 RPE，使未使用的葡萄糖从脉络膜传递到高度糖酵解的脂质分泌物。主要是通过脂蛋白，其中一些支持操作系统的再生，另一些则积累为 AMD 的典型细胞外沉积物面临大量脂质负荷的细胞的一个特征是脂质的形成。液滴（LD），动态调节脂质运输、代谢和细胞内脂质储存细胞器不同细胞类型之间的特定 LD 功能差异很大。视觉周期生物学的背景，但它们的生理学和在维持非视黄醇脂质稳态中的作用 RPE 本质上尚未被探索过。该提案研究了 LD 在人类中的组成、生理学和作用。 RPE 脂质稳态的总体假设有两个：a) LD 可以暂时储存多种脂质。来自 RPE 每日脂质负荷的脂质，防止其脂质过氧化；和 b) 从 LD 释放的脂质；特定的酶优先在线粒体中代谢，而不是通过促进脂质氧化来分泌。代谢超过脂质分泌，RPE LD 可能增强对光感受器的代谢支持并降低 AMD 中观察到的病理性细胞外脂质积累为了检验这一假设，将喂食不同的脂质负荷。原代和诱导多能干细胞 (iPSC) 来源的人 RPE 培养物，并评估 LD 成分 LD 释放的脂质的命运将通过显微镜、生化方法进行追踪。主要研究者的长期目标是开发定义细胞内 RPE 的专业知识。增强 RPE 脂质稳态并减少病理性细胞外脂质的脂质运输途径沉积，为 AMD 开辟新的治疗途径。职业发展计划 (CDP) 重点关注 RPE 脂质生物学，建立 iPSC-RPE 培养方面的专业知识，放射性标记脂质追踪、高分辨率显微镜、生物能量分析和脂质组学。导师团队利用密歇根大学在脂质生物学和脂质组学方面的深厚专业知识和拥有成功指导 K 获奖者独立研究的记录。本提案中的教学和实践经验确保研究者成为一名成功的 AMD- 专注于临床医生，拥有独立的基础科学项目，利用 RPE 脂质生物学来了解 AMD。