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：
10557192
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 2027-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10557192
关键词：
Age related macular degeneration Apical Award Basic Science Biochemical Bioenergetics Biology Blindness Cell Nucleus Cell Respiration Cells Characteristics Choroid Consumption Data Deposition Development Plans Disease Drusen Dryness 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 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 Tissues 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 pharmacologic prevent programs response 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：与年龄相关的黄斑变性（AMD）以视网膜色素上皮（RPE）脂质dys-标记体内平衡，包括病理性细胞外脂质积累，线粒体脂质代谢受损和脂质过氧化增加，一种脂质氧化损伤的有毒形式。 RPE通常在视网膜脂质稳态，消耗和分泌大量的脂质。脂质消耗来自每日较大的脂质负荷的形式，包括脉络膜中的脂蛋白摄取和富含脂质的吞噬作用光感受器外部段（OS）。其中一些脂质在线粒体中被氧化代谢，产生有效支持光感受器的代谢产物。脂质氧化代谢还可以最大程度地减少葡萄糖的使用通过RPE，允许葡萄糖从脉络膜传递到高糖酵解感光体。脂质分泌主要是通过脂蛋白，其中一些支持OS再生，其中一些丙烯酸 AMD的典型细胞外沉积。面向大脂质负荷的细胞的特征是脂质的形成液滴（LD），细胞内脂质储存细胞器，可动态调节脂质运输，代谢和脂质过氧化。特定的LD功能在不同的细胞类型之间广泛范围。 RPE LD已研究视觉周期生物学的背景，但它们在维持非类脂脂稳态中的生理和作用 RPE本质上是出乎意料的。该提案考试LD在人类中的组成，生理和作用 RPE脂质稳态。章节过度假设是两个方面：a）ld可以暂时存储大范围脂质源自RPE的每日脂质负荷，防止其脂质过氧化； b）从LD释放的脂质特定的酶在线粒体中更优选代谢，而不是分泌。通过促进脂质氧化 RPE LD对脂质分泌的代谢可能会增强对感光体的代谢支持并减少在AMD中看到的病理细胞外脂质的积累。为了检验假设，将喂养各种脂质负荷对原代和诱导的多能干细胞（IPSC）衍生的人RPE培养物，并评估了LD组成通过质谱法。 LD释放的脂质的命运将通过显微镜，生化方法，和脂质组学。主要研究者的长期目标是开发专业知识来定义细胞内RPE 增强RPE脂质稳态并减少病理外脂质的脂质运输途径沉积，为AMD开辟了新的治疗途径。为了实现这一目标，首席调查员的职业发展计划（CDP）专注于RPE脂质生物学，建立IPSC-RPE文化专业知识，放射标记的脂质跟踪，高分辨率显微镜，生物能分析和脂质组学。 CDP的 Menorship团队利用密歇根大学的脂质生物学和脂质组学方面的深厚专业知识和拥有成功心理的K获奖者的田径记录，以研究独立性。结合该提案中的教学和实践经验可确保调查人员成为成功的AMD- 专注于临床医生，具有独立的基础科学计划，利用RPE脂质生物学来了解AMD。