Gene therapy to support cone metabolism in retinitis pigmentosa

支持色素性视网膜炎视锥细胞代谢的基因疗法

• 批准号: 8622203
• 负责人: CONSTANCE L CEPKO
• 金额: $ 41.53万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8622203
• 关键词: Address; Affect; Age related macular degeneration; Antioxidants; Area; Autophagocytosis; Binding Proteins; Biogenesis; Biological Preservation; Blindness; Carbon; Cessation of life; Charge; Clinical Trials; Color; Cone; Disease; Drug Metabolic Detoxication; Environment; Enzymes; Equilibrium; Eye; Free Radicals; Gene Combinations; Generic Drugs; Genes; Genetic; Glucose; Glucose Transporter; Glutathione; Human; Injection of therapeutic agent; Insulin; Ions; Isocitrate Dehydrogenase; Lead; Lesion; Lipids; Mediating; Membrane; Metabolic; Metabolic stress; Metabolism; Mitochondria; Modeling; Molecular Chaperones; Monocarboxylic Acid Transporters; Mus; NADP; Nuclear; Nucleic Acids; Nutrient; Outcome; Oxidoreductase; PPAR gamma; Pathway interactions; Patients; Pentosephosphate Pathway; Phosphorylation; Photoreceptors; Phototransduction; Proteins; Quality of life; Regulation; Regulator Genes; Regulatory Element; Retina; Retinal Cone; Retinitis Pigmentosa; Sterols; Stress; Superoxide Dismutase; Surface; Viral Vector; Vision; Work; adeno-associated viral vector; catalase; cell type; combat; experience; fighting; gene therapy; human FRAP1 protein; malic enzyme; mouse model; oxidation; programs; public health relevance; retinal rods; sugar; transcription factor

DESCRIPTION (provided by applicant): Blindness is often caused by genetic lesions that directly affect photoreceptors. There are >200 disease genes in humans that lead to blindness (retnet:www.sph.uth.tmc.edu/Retnet). Addressing each genetic deficit by transduction of a gene specific to that disease would be a large and expensive undertaking. As an alternative, gene therapy can be used to attack a problem common to multiple genetic forms of blindness. One such approach is to preserve cone function in retinitis pigmentosa (RP). People with RP initially have poor night vision, as rods are dysfunctional. Rods are then lost, which is followed by loss of cone function, and then cones themselves. As cones do not express the disease gene in most cases, there must be a non-autonomous cause of cone death. If this cause can be identified, and combated, a more generic form of therapy can be developed. Using 4 mouse models of RP, and an unbiased microarray approach, we discovered that many genes involved in the regulation of metabolism were altered at the onset of cone death. We further showed that mTOR, a key regulator of metabolism, was not phosphorylated in RP cones. This is now the earliest sign of cone stress in RP that is known. As the disease progressed, we discovered that cones carried out chaperone- mediated autophagy. Injection of insulin into RP mice, which can lead to increased activity of mTOR, increased survival of cones. We have suggested a model wherein cones are dysfunctional and then die due to dysregulated metabolism. As rods are the major cell type in the ONL, cones experience a greatly altered environment following rod death. The cone OS collapse, they lose their intimate association with the RPE, and they are exposed to a hyperoxic environment. They show greater oxidation of their nucleic acids, proteins, and lipids. Fighting oxidation may cause cones to require more NADPH, which is generated from glucose via the pentose phosphate pathway (PPP). It is also produced by two cytosolic enzymes, malic enzyme and isocitrate dehydrogenase. If glucose is shuttled to the PPP, the glycolytic pathway would slow, which could lead to several metabolic outcomes, including reducing the surface area of cones, as well as reducing phototransduction and potentially the ATP levels. We wish to develop AAV-mediated gene therapy to combat metabolic stress in the cones in RP. As cone-mediated vision is of greatest importance to humans, preservation of cone function is critical to the quality of life among RP patients. If such therapies can be developed, it is also possible that these therapies can be extended to other diseases where cones are compromised, such as age-related macular degeneration (AMD).

描述（由申请人提供）：失明通常是由直接影响光感受器的遗传病变引起的。在人类中有超过200种疾病基因导致失明（retnet：www.uth.tmc.edu/Retnet）。通过转导该疾病特有的基因来解决每一个遗传缺陷将是一项庞大而昂贵的任务。作为一种替代方法，基因治疗可以用来解决多种遗传形式的失明所共有的问题。一种这样的方法是保留视网膜色素变性（RP）中的视锥功能。患有RP的人最初的夜视能力很差，因为杆功能失调。然后失去了杆，随之而来的是锥功能的丧失，然后是锥本身。由于视锥细胞在大多数情况下不表达疾病基因，因此必须有非自主的视锥细胞死亡原因。如果能够确定并消除这种原因，就可以开发出一种更通用的治疗方法。使用4种RP小鼠模型和无偏倚的微阵列方法，我们发现许多参与代谢调节的基因在视锥细胞死亡开始时发生了改变。我们进一步表明，mTOR，一个关键的调节代谢，不磷酸化RP锥。这是目前已知的RP中锥应力的最早迹象。随着疾病的发展，我们发现视锥细胞进行分子伴侣介导的自噬.将胰岛素注射到RP小鼠中，这可以导致mTOR活性增加，增加视锥细胞的存活。 我们已经提出了一个模型，其中视锥细胞功能失调，然后由于代谢失调而死亡。由于视杆细胞是ONL中的主要细胞类型，视锥细胞在视杆细胞死亡后经历了极大改变的环境。视锥OS崩溃，它们失去了与RPE的密切联系，并且它们暴露于高氧环境。它们的核酸、蛋白质和脂质的氧化程度更高。抗氧化可能会导致视锥细胞需要更多的NADPH，这是由葡萄糖通过磷酸戊糖途径（PPP）产生的。它也由两种胞质酶，苹果酸酶和异柠檬酸脱氢酶产生。如果葡萄糖被运送到PPP，糖酵解途径将减慢，这可能导致几种代谢结果，包括减少视锥细胞的表面积，以及减少光转导和潜在的ATP水平。 我们希望开发AAV介导的基因治疗来对抗RP中视锥细胞的代谢应激。视锥细胞介导的视觉对人类至关重要，视锥细胞功能的保护对RP患者的生活质量至关重要。如果能够开发出这种疗法，这些疗法也有可能扩展到其他视锥细胞受损的疾病，如年龄相关性黄斑变性（AMD）。