Regulated Transgene Expression in the Retina

描述（由申请人提供）：本申请涉及基因组学的广泛挑战领域（领域08），具体挑战主题是08- ey -101：复杂眼病的基因组学。影响视力的疾病已经成为基因治疗的潜在候选者。将病毒载体（如基于腺相关病毒（AAV）的病毒载体）直接注射到眼睛的不同隔室中，导致基因转移和在各种细胞类型中稳定的转基因表达。视网膜下注射AAV载体可实现视网膜色素上皮细胞和光感受器的高水平转导；这种方法已经在动物模型和人类身上被用于治疗先天性失明，即莱伯先天性黑朦。许多其他形式的获得性和遗传性失明是基因治疗的潜在候选者，尽管在许多情况下，有必要调节转基因的表达，以确保无毒性的治疗性表达。本提案将开发一种引入视网膜后对aav编码基因进行药理学调节的方法，用于治疗湿型年龄相关性黄斑变性（AMD）。该方法的基础是在诱导启动子的控制下，引入一种编码血管内皮生长因子（VEGF）抗体的基因，以及一种编码工程转录因子的基因，这种转录因子可以被一个小分子激活，以特异性地增强转基因的表达。这种被称为ARGENT的转基因诱导表达方法将利用便捷的报告基因在小鼠和猴子的视网膜中发展。研究将在AMD小鼠模型中使用编码人源化VEGF抗体Avastin的载体进行；这些载体还将在猴子身上进行安全性和药代动力学试验。ARGENT系统用于AMD的开发将提供一个基因治疗平台，可应用于广泛的视网膜疾病。此应用程序的资金将创造2个新的工作岗位。这些职位的候选人已在预算说明中列出。

DESCRIPTION (provided by applicant): This application addresses the broad Challenge Area of Genomics (area 08) and the specific Challenge Topic is 08-EY-101: Genomics of complex eye diseases. Diseases that affect visual acuity have emerged as potential candidates for gene therapy. Direct injection of viral vectors, such as those based on adeno- associated viruses (AAV), into different compartments of the eye leads to gene transfer and stable transgene expression into various cell types. High level transduction of retinal pigmented epithelial cells and photoreceptors can be achieved following sub-retinal injection of AAV vectors; this approach has been used to treat a congenital form of blindness called Leber congenital amaurosis in animal models and humans. Many other forms of acquired and inherited blindness are potential candidates for gene therapy although in many cases it will be necessary to regulate expression of the transgene so as to assure therapeutic expression without toxicity. This proposal will develop a method for pharmacologically regulating AAV-encoded genes after introduction into the retina for the treatment of the wet form of age-related macular degeneration (AMD). The method is based on the introduction of a gene encoding an antibody to vascular endothelial growth factor (VEGF) under the control of an inducible promoter together with genes encoding an engineered transcription factor that can be activated by a small molecule to specifically enhance expression of the transgene. This method of inducible transgene expression called ARGENT will be developed in retina of mice and monkeys using convenient reporter genes. Studies will be performed with vectors encoding the humanized VEGF antibody called Avastin in mouse models of AMD; these vectors will also be tested in monkeys for safety and pharmacokinetics. Development of the ARGENT system for AMD will provide a platform of gene therapy that can be applied to a broad array of retinal diseases. Funding of this application will create 2 new jobs. Candidates have been identified for these positions as described in the Budget Justification. PUBLIC HEALTH RELEVANCE: Age-related macular degeneration (AMD) is a growing disease: 1.7 million people developed AMD in 1995 while it is projected that 6.3 million will be affected in 2030. The disease is a major cause for visual disability among persons over 60 years of age that with the increase in life expectancy is not only a medical problem but also one with a significant socio-economic impact. This proposal is designed to develop a gene therapeutic that will provide significant medical relief to patients, develop technologies applicable to other indications in the eye and minimize therapeutic interventions and the burden on the healthcare system.