Recapitulation of the two-cell visual cycle in photoreceptors and its effects on retinoid flux and remedy of toxic retinoid species

光感受器中双细胞视觉周期的概括及其对类视黄醇通量的影响以及有毒类视黄醇种类的补救

• 批准号: 10609438
• 负责人: Zachary John Engfer
• 金额: $ 4.25万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10609438
• 关键词: 11 cis Retinal; 11-cis-Retinol; Affect; Age; All-Trans-Retinol; Back; Binding; Biochemical; Biochemical Pathway; Biochemistry; Blindness; Brain; Cell Death; Cells; Chemicals; Chronic; Cone; Coupled; Coupling; Darkness; Defect; Degenerative Disorder; Disease; Electrophysiology (science); Electroretinography; Engineering; Enzymes; Esters; Ethanolamines; Eye; Fatty Acids; Functional disorder; Future; Genetic; Health; Helper-Inducer T-Lymphocyte; High Pressure Liquid Chromatography; Human; Immunohistochemistry; Immunology; Isomerism; Kinetics; Knock-in; Knock-in Mouse; Knock-out; Knockout Mice; Knowledge; Lasers; Lead; Light; Link; Molecular; Molecular Biology; Molecular Evolution; Morphology; Muller' s cell; Mus; Natural regeneration; Ophthalmoscopy; Opsin; Optic Nerve; Optical Coherence Tomography; Patients; Phenotype; Photoreceptors; Phototransduction; Physiological; Pigments; Proteins; Quality of life; RPE65 protein; Reaction; Recycling; Regenerative pathway; Research Technics; Resistance; Retina; Retinal Degeneration; Retinal Diseases; Retinal Dystrophy; Retinal Pigments; Retinal dehydrogenase; Retinoids; Retinol dehydrogenase; Rod; Scanning; Signal Transduction; Structure of retinal pigment epithelium; Supporting Cell; Testing; Therapeutic; Therapeutic Intervention; Training; Travel; Vertebrate Photoreceptors; Vision; Visual; Visual Fields; Visual impairment; Work; cell killing; cell type; chromophore; crosslink; experience; lecithin-retinol acyltransferase; mouse model; remediation; retinal damage; retinol isomerase; sex; stem; therapeutic gene; treatment optimization; vision science; visual cycle

PROJECT SUMMARY/ ABSTRACT. Retinal degenerative (RD) diseases result in a progressive loss of vision, and have a devastating impact on a patient’s quality of life. Many genetic factors that nucleate these diseases are intricately linked to defects in the visual (retinoid) cycle. This cycle is necessary for regenerating the essential visual pigment 11-cis-retinal after it is photoisomerized to all-trans-retinal; errors in this multi-step recycling of all-trans-retinal back to 11-cis- retinal leads to the buildup of toxic retinoid photo-oxidation products that can kill photoreceptors and the supporting retinal pigment epithelium (RPE). Few therapeutic options exist for mitigating the damage that is caused by these photo-oxidation products, especially after cell death in the retina has started to affect quality of vision. Normally, the vertebrate visual cycle is distributed across two distinct cell types, the retinal pigment epithelium and the photoreceptors (i.e., rods and cones). In the functional visual cycle, 11-cis-retinal is initially bound to opsin proteins within the photoreceptors, where it is then isomerized to all-trans-retinal in the presence of light. This transformation initiates the phototransduction signaling cascade that travels through optic nerve to the brain, where the signals are integrated into a coherent visual field. The all-trans-retinal molecules are then shed by opsins and converted to all-trans-retinol by all-trans-retinal dehydrogenase. The all-trans-retinol is then transported from the photoreceptors to one of two “helper” cell types- RPE cells that support both rod and cone function, and Müller cells that solely support cones. Because RPE-linked visual cycle dysfunction has a greater impact on the retina as a whole, we’ve elected to focus on just the RPE-based visual cycle and not the cone- exclusive alternative visual cycle. When all-trans-retinol is transported from the photoreceptors to the RPE, the all-trans-retinol undergoes two key reactions; one catalyzed by lecithin-retinol acyltransferase (abbr. Lrat), and the other by retinal pigment epithelium-specific 65 kDa (abbr. Rpe65). Lrat catalyzes the coupling of all-trans retinol to fatty acids, forming stable retinyl ester intermediates. These retinyl esters are subsequently isomerized and hydrolyzed by Rpe65 to give 11-cis-retinol. 11-cis-retinol is then oxidized to 11-cis-retinal by 11-cis-retinol dehydrogenases and transported back to the photoreceptors for re-use. When the visual cycle is hindered, all-trans retinal can build up in the photoreceptors, leading to the formation of toxic photo-oxidation products that cause retinal degeneration. I intend to expand our knowledge of the visual cycle via engineered expression of Lrat and Rpe65 in the photoreceptors. In studying how manipulation of retinoid flux in the visual cycle controls the emergence and progression of RD, we can optimize therapeutic interventions that target the central drivers of retinal disease, while simultaneously reversing the toxic buildup of retinoids in chronic RD.

项目摘要/摘要。 视网膜退化性（RD）疾病导致视力逐渐丧失，并对A产生毁灭性的影响 病人的生活质量。核这些疾病的许多遗传因素与缺陷有关 视觉（类维生素）周期。此循环对于在11 cis-续订的基本视觉颜料重新生成后是必需的 它被光化为全反视网膜；在全反视网膜的多步回收中，错误回到11 cis- 视网膜导致有毒性类维生素性光氧化产物积聚，可以杀死感光器和 支持视网膜色素上皮（RPE）。减轻损害的治疗选择很少 由这些光氧化产物引起，尤其是在视网膜中细胞死亡后开始影响质量 视觉。 通常，脊椎动物的视觉周期分布在两种不同的细胞类型上，视网膜色素上皮 以及感光器（即杆和锥体）。在功能性视觉周期中，11- cis视网膜最初与 在光感受器中，在光感受器中，在光照下，在光中，在光线下将其异构化。 这种转换启动了通过视神经传递到光神的光转导信号级联 大脑，信号集成到相干的视野中。然后，全反视网膜分子是 由Opsins脱离，并被全反视网膜脱氢酶转化为全反元素。那时全反替诺醇 从光感受器运输到两种“助手”细胞类型的一种 - 支持杆和锥的RPE细胞 功能和仅支持锥的müller细胞。因为RPE连接的视觉周期功能障碍具有更大的 对整个视网膜的影响，我们选择仅关注基于RPE的视觉周期，而不是锥体 独家替代视觉周期。当将全反元素从感光器传输到RPE时， 全反元素经历了两个关键反应。一种由卵磷脂 - 归他醇酰基转移酶（abbr。lrat）催化的，而 另一个由视网膜色素上皮特异性65 kDa（abbr。rpe65）。 LRAT催化全班耦合 视黄醇到脂肪酸，形成稳定的视黄酯中间体。这些视黄酯随后是 由RPE65异构化并水解为11-CIS-返回醇。然后将11-CIS-雷丁醇通过氧化为11- cis-retinal 11-CIS-他醇脱氢酶，并将其转移回感光器以重复使用。当视觉周期为 受阻，全反式视网膜可以在感光器中积聚，从而导致有毒光氧化形成 导致常规变性的产品。 我打算通过在LRAT的工程表达和RPE65中扩展我们对视觉周期的了解 感受器。在研究视觉循环中类类类细胞素通量如何控制出现和 RD的进展，我们可以优化针对残留疾病中心驱动因素的治疗干预措施， 同时逆转了慢性路的类视黄素的有毒积累。