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.

项目概要/摘要 尽管抗 VEGF 疗法已显示出对年龄相关湿型患者的显着益处 黄斑变性（AMD），对于干性 AMD 尚无有效的治疗方法，这是一个未满足的主要视网膜需求。 色素上皮（RPE）和视网膜功能障碍和变性是干眼症的主要病理特征 AMD 认为线粒体功能缺陷和 RPE 脂质代谢紊乱是关键。 然而，干性 AMD 失调的分子机制。 AMD 的 RPE 中的脂质代谢是难以捉摸的。 转录因子调节脂质代谢，因此临床上使用PPARα激动剂来治疗。 尽管我们最近的研究表明 PPARα 对视网膜具有保护作用，但这种关联。 PPARα 与 AMD 发病机制的关系仍不清楚。我们的初步研究表明，PPARα 与 AMD 的发病机制有关。 在患有干性 AMD 的人类捐赠者和两种患有干性 AMD 的动物模型中，其视网膜和 RPE 的水平下调。 此外，RPE 中 PPARα 的激活或表达部分保护了 AMD 的表型。 视网膜和 RPE 对抗氧化应激引起的 RPE 和视网膜损伤 我们已经证明 PPARα。 单独敲除（KO）会导致与年龄相关的 ERG 下降、视网膜变性、RPE 细胞形态异常、 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 膜中的脂质积累，因此，我们对此进行了努力。 PPARα 是 RPE 中脂肪酸氧化 (FAO) 和脂质稳态的主要调节因子，对于维持 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 RPE 中，我们将分析 RPE 屏障功能、RPE 细胞形态和功能的变化。 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积累 在常规饮食或高脂肪、富含胆固醇 (HFC) 的 PPARα-CKO 小鼠的 RPE 和 Bruch 膜中 饮食，以揭示仅在 RPE 中 PPARα 消融是否会诱发视网膜和 RPE 病变，这将是 HFC 饮食会加速和加剧这种情况，我们还将确定 PPARα 的消除是否会减少 FFA 和 FFA。 增加 RPE 中的糖酵解，将进行 PPARα-CKO RPE 的蛋白质组学分析以鉴定酶。 PPARα-CKO 小鼠 RPE 中的脂质结合蛋白水平发生变化，此外，我们将研究是否存在这种情况。 PPARα-Tg 小鼠将表现出减轻，而 PPARα-CKO 小鼠将表现出更严重的 RPE 和视网膜损伤 我们还将探讨 PPARα 激动剂非诺贝特对 RPE 和氧化应激的治疗潜力。 两种具有某些 AMD 表型的遗传小鼠模型的视网膜功能障碍和变性。 研究将确定 RPE 中脂质代谢的新调节机制，并有可能导致 重新利用口服降脂药物治疗干性 AMD。