Novel Adeno-Associated Viral Therapy for X-linked Retinitis Pigmentosa

X连锁色素性视网膜炎的新型腺相关病毒疗法

• 批准号: 7927797
• 负责人: Karen Kozarsky
• 金额: $ 282.27万
• 依托单位: REGENX BIOSCIENCES, LLC
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7927797
• 关键词: Accounting; Age-Months; Animal Model; Biodistribution; Biological Preservation; Blindness; Canis familiaris; Cell Nucleus; Clinical; Codon Nucleotides; Complementary DNA; Cytomegalovirus; Data; Defect; Dependovirus; Disease; Dose; Early Promoters; Electroretinography; Enhancers; Evaluation; Eye; Gene Expression; Genes; Goals; Government; Guanosine Triphosphate Phosphohydrolases; Healthcare Systems; Histologic; Histology; Inflammation; Inherited; Knock-out; Knockout Mice; Lead; Length; Link; Medical; Mus; Mutation; Nuclear; Patients; Peripheral; Persons; Phenotype; Photoreceptors; Plasmids; Prevention; Protein Isoforms; Proteins; RNA Splicing; Recombinant adeno-associated virus (rAAV); Regulator Genes; Reporter Genes; Retina; Retinal; Retinal Degeneration; Retinal Diseases; Retinitis Pigmentosa; Rhodopsin; Safety; Serotyping; Structure; Structure of retinal pigment epithelium; Supplementation; Technology; Testing; Therapeutic; Thick; Time; Toxicology; Transgenes; Variant; Viral; Vision; Vitamins; Wild Type Mouse; adeno-associated viral vector; cell type; comparative efficacy; design; disease-causing mutation; gene replacement; gene therapy; in vivo; mouse model; nonhuman primate; novel; prevent; promoter; public health relevance; response; therapeutic gene; transgene expression; vector

DESCRIPTION (provided by applicant): The goal of this project is to develop a gene therapeutic for retinitis pigmentosa (RP). RP is the most common inherited form of blindness, and is characterized by photoreceptor loss, leading to a progressive loss of peripheral as well as night vision. There is no treatment for RP, which is a group of diseases caused by mutations in one of multiple genes that lead to similar phenotypes. X-linked retinitis pigmentosa (XLRP) is a form of RP that is most often caused by mutations in a gene encoding the photoreceptor protein RPGR (retinitis pigmentosa GTPase regulator), and is relatively common, accounting for approximately 10% of all cases of RP. Most mutations in RPGR are recessive, indicating that gene replacement can be an effective strategy. Recombinant adeno-associated virus (AAV) vectors have been showing great promise in delivering genes in animal models of retinal disease, giving long-term, stable gene expression without inflammation. Novel AAV serotypes including AAV8 have been identified which target the retinal pigment epithelium (RPE) or the photoreceptor layer, and transduce those cell types with higher efficiency than previously known serotypes of AAV. This project proposes to use AAV8, which excels at delivering genes to photoreceptors, to develop a therapeutic for XLRP. Initially, optimization studies will be performed to identify the most effective clinical candidate for RPGR gene replacement, and then safety and toxicology studies will be performed with the proposed clinical candidate, with the goal of filing an IND by the end of the project period. Initially, several alternative isoforms of the RPGR cDNA will be tested in the mouse model of XLRP, the RPGR knockout mouse, to determine which is the most effective in preventing retinal degeneration. When the optimal cDNA is selected, the promoter will then be optimized, testing both a constitutive (CMV) promoter and a photoreceptor- specific (rhodopsin) promoter to determine if one promoter has an efficacy advantage over the other. The promoters will also be used with a reporter gene in normal mice and non-human primates to confirm that both are stable for long-term transgene expression. The final vector construct will also be used to determine the minimal dose of vector required for biologic effect in the RPGR knockout mouse. Finally, the clinical candidate, with the AAV8 serotype, and optimized promoter and RPGR transgene will be put through biodistribution and safety/toxicology studies in mice and in dogs to complete the package of data needed for filing an IND. The proposed gene therapeutic for XLRP will serve an unmet medical need in RP patients, and will be a novel "first-in-class" therapy that will provide a platform for treating additional forms of RP and other retinal diseases. PUBLIC HEALTH RELEVANCE: Retinitis pigmentosa is the most common inherited form of blindness, with an estimated 100,000 patients in the US. It is characterized by progressive loss of peripheral as well as night vision, eventually resulting in blindness. 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 the burden on the healthcare system.

描述（申请人提供）：本项目的目标是开发视网膜色素变性（RP）的基因治疗药物。RP是最常见的遗传性失明形式，其特征在于光感受器丧失，导致周边视力和夜间视力的进行性丧失。RP是一组由导致相似表型的多个基因之一突变引起的疾病，目前尚无治疗方法。X连锁视网膜色素变性（XLRP）是一种RP形式，最常见的是由编码感光蛋白RPGR（视网膜色素变性GTGR调节因子）的基因突变引起的，并且相对常见，约占所有RP病例的10%。RPGR中的大多数突变是隐性的，表明基因替换可以是一种有效的策略。重组腺相关病毒（AAV）载体在视网膜疾病的动物模型中递送基因，提供长期稳定的基因表达而无炎症方面显示出巨大的前景。已经鉴定了靶向视网膜色素上皮（RPE）或光感受器层的新的AAV血清型，包括AAV 8，并且以比先前已知的AAV血清型更高的效率转染那些细胞类型。该项目建议使用擅长将基因传递到感光细胞的AAV 8来开发XLRP的治疗方法。最初，将进行优化研究，以确定RPGR基因替代的最有效临床候选药物，然后将对拟议的临床候选药物进行安全性和毒理学研究，目标是在项目期结束前提交IND。最初，将在XLRP的小鼠模型（RPGR敲除小鼠）中测试RPGR cDNA的几种替代同种型，以确定哪一种在预防视网膜变性方面最有效。当选择最佳cDNA时，然后优化启动子，测试组成型（CMV）启动子和光感受器特异性（视紫红质）启动子以确定一种启动子是否具有优于另一种的功效。启动子也将与报告基因一起用于正常小鼠和非人灵长类动物中，以确认两者对于长期转基因表达都是稳定的。最终载体构建体还将用于确定RPGR敲除小鼠中生物效应所需的载体的最小剂量。最后，具有AAV 8血清型和优化的启动子和RPGR转基因的临床候选物将在小鼠和狗中进行生物分布和安全性/毒理学研究，以完成提交IND所需的数据包。所提出的XLRP基因治疗剂将满足RP患者未满足的医疗需求，并且将是一种新的“一流”疗法，其将为治疗其他形式的RP和其他视网膜疾病提供平台。 公共卫生相关性：视网膜色素变性是最常见的遗传性失明形式，在美国估计有10万患者。其特征是周边视力和夜间视力逐渐丧失，最终导致失明。该提案旨在开发一种基因治疗药物，为患者提供显著的医疗救济，开发适用于眼睛其他适应症的技术，并最大限度地减少医疗保健系统的负担。