Dysregulation of PPARα in RPE degeneration

RPE 变性中 PPARα 的失调

• 批准号: 10736062
• 负责人: Jian-Xing Ma
• 金额: $ 54.59万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-30 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10736062
• 关键词: 3-nitrotyrosine; ATP-Binding Cassette Transporters; Ablation; Acceleration; Adherence; Age; Age related macular degeneration; Agonist; Animal Model; Binding Proteins; Bruch' s basal membrane structure; Carnitine Palmitoyltransferase I; Cell Size; Cells; Cellular Morphology; Cholesterol; Clinical; Cryoultramicrotomy; DNA copy number; Deposition; Diet; Disease; Drusen; Dyslipidemias; Energy-Generating Resources; Enzymes; Event; Eye; Fatty acid glycerol esters; Fenofibrate; Functional disorder; Fundus; Genes; Genetic; Genotype; Genus Hippocampus; Glucose; Glycolysis; Histology; Histopathology; Homeostasis; Human; Impairment; Infiltration; Inflammation; Inflammatory; Ingestion; Injections; Knock-out; Knockout Mice; Ligands; Lipid Binding; Lipids; LoxP-flanked allele; Macrophage; Measures; Mediating; Metabolic stress; Microglia; Mitochondria; Mitochondrial DNA; Molecular; Mus; Nonexudative age-related macular degeneration; Nuclear Receptors; Optical Coherence Tomography; Oral; Oxidative Stress; Oxidative Stress Induction; PF4 Gene; PPAR alpha; Pathogenesis; Pathogenicity; Pathologic; Pathology; Patients; Phagocytosis; Pharmacotherapy; Phenotype; Photoreceptors; Play; Production; Proteins; Proteomics; Regulation; Retina; Retinal Degeneration; Retinol dehydrogenase; Role; Structure; Structure of retinal pigment epithelium; Therapeutic; Thick; Tissues; Transgenic Mice; Tuberous Sclerosis; Virulence Factors; age related; bevacizumab; conditional knockout; driving force; drug repurposing; effective therapy; epithelial injury; fatty acid oxidation; fatty acid-binding proteins; lipid metabolism; lipid transport; mitochondrial dysfunction; mouse model; neuronal survival; new therapeutic target; overexpression; oxidation; oxidative damage; retinal damage; sodium iodate; transcription factor

PROJECT SUMMARY/ABSTRACT Although anti-VEGF therapies have shown impressive benefits for patients with wet form age-related macular degeneration (AMD), there is no effective treatment for dry AMD, a major unmet clinical need. Retinal pigment epithelium (RPE) and retina dysfunction and degeneration are the major pathological features in dry AMD. Deficient mitochondrial function and disturbed lipid metabolism in the RPE are believed to play key pathogenic roles in these pathologies of dry AMD. However, the molecular mechanism for the dysregulation of lipid metabolism in the RPE with AMD is elusive. Peroxisome Proliferator-Activated Receptor α (PPARα) is a transcription factor. It regulates lipid metabolism, and thus, PPARα agonists are used clinically to treat dyslipidemia. Although our recent study showed that PPARα has a protective role in the retina, the association of PPARα with the pathogenesis of AMD remains unknown. Our preliminary studies demonstrated that PPARα levels are down-regulated in the retina and RPE of human donors with dry AMD and in two animal models with partial AMD phenotypes. Furthermore, activation or expression of PPARα in the RPE partially protected the retina and RPE against oxidative stress-induced RPE and retina damage. We have demonstrated that PPARα knockout (KO) alone resulted in age-related ERG decline, retinal degeneration, abnormal RPE cell morphology, enlarged RPE cell size, impaired RPE barrier, and increased microglia/macrophage adherence to the RPE. PPARα KO also induced lipid accumulation in the RPE and Bruch’s membrane. Thus, we hypothesize that PPARα is a major regulator of fatty acid oxidation (FAO) and lipid homeostasis in the RPE, and essential for maintaining normal structure and function of the RPE and retina. In this project, we will use our newly generated RPE-specific PPARα conditional KO (PPARα-CKO) mice and transgenic (PPARα-Tg) mice expressing PPARα in the RPE for the proposed studies. We will analyze changes in RPE barrier function, RPE cell morphology and cell size, ERG, retinal and photoreceptor cell layer thicknesses, subretinal inflammation, and lipid accumulation in the RPE and Bruch’s membrane of PPARα-CKO mice under a regular diet or high-fat, cholesterol-rich (HFC) diet, to reveal if PPARα ablation in the RPE alone will induce retina and RPE pathologies, which will be accelerated and exacerbated by the HFC diet. We will also determine if PPARα ablation will decrease FAO and increase glycolysis in the RPE. Proteomic analysis of PPARα-CKO RPE will be performed to identify enzymes and lipid-binding proteins with changed levels in the RPE of PPARα-CKO mice. Further, we will investigate if PPARα-Tg mice will show alleviated, while PPARα-CKO mice will show more severe, RPE and retinal injury by oxidative stress. We will also explore the therapeutic potential of PPARα agonist fenofibrate against RPE and retinal dysfunction and degeneration in two genetic mouse models with some AMD phenotypes. The proposed studies will identify a new regulation mechanism for lipid metabolism in the RPE and has the potential to lead to the repurposing of an oral lipid-lowering drug for the treatment of dry AMD.

项目总结/摘要 尽管抗VEGF治疗对湿型年龄相关性高血压患者有显著的益处， 由于黄斑变性（AMD），没有有效的治疗干性AMD的方法，这是一个主要的未满足的临床需求。视网膜 色素上皮（RPE）和视网膜功能障碍和变性是干性视网膜病变的主要病理特征。 AMD. RPE中线粒体功能缺陷和脂质代谢紊乱被认为是关键 在干性AMD的这些病理中的致病作用。然而，调节失调的分子机制， 患有AMD的RPE中的脂质代谢是难以捉摸的。过氧化物酶体增殖物激活受体α（过氧化物酶体增殖物激活受体α）是一种 转录因子它调节脂质代谢，因此，PPARα激动剂在临床上用于治疗 血脂异常虽然我们最近的研究表明，PPARα在视网膜中具有保护作用，但这种关联 PPARα与AMD发病机制的关系尚不清楚。我们的初步研究表明， 在患有干性AMD的人供体的视网膜和RPE中以及在患有 部分AMD表型。此外，在RPE中激活或表达PPARα部分地保护了细胞的增殖。 视网膜和RPE对抗氧化应激诱导的RPE和视网膜损伤。我们已经证明， 单独敲除（KO）导致年龄相关的ERG下降、视网膜变性、异常RPE细胞形态， RPE细胞尺寸增大，RPE屏障受损，小胶质细胞/巨噬细胞对RPE的粘附增加。 PPARα KO还诱导RPE和Bruch膜中的脂质蓄积。因此，我们假设， PPARα是RPE中脂肪酸氧化（FAO）和脂质稳态的主要调节因子，对于RPE的生长至关重要。 维持RPE和视网膜的正常结构和功能。在这个项目中，我们将使用我们新生成的 RPE特异性PPARα条件性KO（PPARα-CKO）小鼠和表达PPARα的转基因（PPARα-Tg）小鼠 在建议的研究的RPE中。我们将分析RPE屏障功能、RPE细胞形态和 细胞大小、ERG、视网膜和感光细胞层厚度、视网膜下炎症和脂质蓄积 在常规饮食或高脂、高胆固醇（HFC）条件下的PPARα-CKO小鼠RPE和Bruch膜中 饮食，以揭示单独在RPE中的PPARα消融是否会诱导视网膜和RPE病理学，这将是 氢氟碳化合物饮食加速并加剧了这种情况。我们还将确定PPARα消融是否会降低FAO， 增加RPE中的糖酵解。将对PPARα-CKO RPE进行蛋白质组学分析，以鉴定酶 和脂质结合蛋白在PPARα-CKO小鼠的RPE中具有变化的水平。此外，我们将调查，如果 PPARα-Tg小鼠将显示减轻，而PPARα-CKO小鼠将显示更严重的RPE和视网膜损伤， 氧化应激我们还将探索PPARα激动剂非诺贝特对RPE的治疗潜力， 在两种具有某些AMD表型的遗传小鼠模型中的视网膜功能障碍和变性。拟议 研究将确定RPE中脂质代谢的新调节机制，并有可能导致 将口服降脂药物用于治疗干性AMD。