Translational Research for Retinal Degeneration Therapies

描述（由申请人提供）：提出了一项多研究者、多中心研究计划，以在用于人类患者之前，完成在由RPGR突变引起的X连锁RP犬模型中开发基于基因的视网膜治疗。这种一致严重的早发性人类疾病在北美占RP病例的约8-10%，在欧洲占15-20%，在单纯性患者中占25%。该申请建立在当前资助期间所取得的成功的基础上，该资助期间开发了基于AAV 5的病毒载体，该病毒载体与人IRBP启动子和人全长RPGR cDNA一起防止视网膜在“慢”疾病模型中退化（XLPRA 1），或在“快”疾病模型中阻止退化并维持光感受器正常完整性（XLPRA 2）。该载体现在用作评估治疗范例的基准治疗试剂，并通过玻璃体内递送途径测试新的治疗方法。该申请将评估RPGRORF 15中的终止或移码突变引起的表型不同的感光细胞变性的犬的基因治疗，并分为3个目标，将：1-评估治疗的长期疗效并确定剂量-反应范围，以确定疗效与毒性剂量~ 2-通过靶向患者治疗促进转化研究-3.对通过玻璃体内途径递送的改良载体进行比较功效研究，以避免受损病变光感受器的二次手术创伤。四个协调模块（M）的描述，利用每个小组的特殊专业知识，以创建一个互补的和重点突出的方法，建议的翻译研究。M1（Large Animal experimental）将制作犬模型，并为这项工作提供基础设施资源~ M2（大型动物治疗）将在犬模型中进行治疗研究，并开发用于结局评估的离体形态学指标~ M3（非侵入性的狗模型）将建立功能和结构疾病特征，并使用选择适合RPGR疾病的非侵入性结果测量来评估治疗的成功，并将结果与离体形态学研究相关联~ M4（分子治疗开发）将提供用于视网膜下和玻璃体内递送的治疗载体。本申请中描述的研究代表了模块科学家之间长期合作的延续，该合作已经将RPE 65-LCA患者的视网膜基因治疗带入I期临床试验。宾夕法尼亚大学领导了与佛罗里达大学的合作。 公共卫生相关性：由RPGR基因突变引起的X连锁视网膜色素变性（XLRP）是人类遗传性视网膜失明的最严重和最常见的原因之一。为了完成用于人类患者的基因治疗的开发，我们将利用已经在两种犬模型中证明有效预防或阻止疾病的病毒载体，并使用视网膜下或玻璃体内递送途径优化与人类患者相当的疾病阶段的治疗。

DESCRIPTION (provided by applicant): A multi-investigator, multi-center research plan is proposed to finalize the development of gene-based retinal therapy in dog models of X-linked RP caused by mutations in RPGR prior to use in human patients. This uniformly severe, early onset human disease accounts for ~ 8-10% RP cases in North America, 15-20% in Europe, and 25% of simplex patients. The application builds on the success achieved during the current funding period which developed an AAV5-based viral vector that, together with the human IRBP promoter and human full-length RPGR cDNA, prevents the retina from degenerating in the 'slow' disease model (XLPRA1), or arrests the degeneration and maintains the photoreceptors at normal integrity in the 'fast' disease model (XLPRA2). This vector now serves as the benchmark therapeutic reagent for assessing treatment paradigms, and testing a novel therapeutic approach via the intravitreal route of delivery. The application will evaluate gene therapy in dogs having phenotypically distinct photoreceptor degenerations caused by stop or frameshift mutations in RPGRORF15, and is divided into 3 aims that will: 1-assess the long term efficacy of treatment and determine the dose-response range to establish efficacy vs toxicity dose~ 2- facilitate translational studies by targeting treatment to patient-relevant disease stage to assess treatment outcomes using criteria established during the current funding period~ 3- carry out comparative efficacy studies on modified vectors delivered via the intravitreal route that avoid secondary surgical trauma in compromised diseased photoreceptors. Four coordinated modules (M) are described that take advantage of the special expertise of each group to create a complementary and focused approach to the proposed translational studies. M1 (Large Animal experimental) will produce the dog models, and provide infrastructure resources for this work~ M2 (Large Animal Therapy) will carry out therapy studies in the canine models and develop ex vivo morphologic measures for outcome assessment~ M3 (Non-invasive Studies-Dog Models) will establish functional and structural disease features, and evaluate success of therapies using non-invasive outcome measures chosen appropriate for RPGR disease, and correlate the results with ex vivo morphologic studies~ M4 (Molecular Therapeutic Development) will provide therapeutic vectors for both subretinal and intravitreal delivery. The research studies described in this application represents a continuation of a longstanding collaboration between the module scientists that already has brought retinal gene therapy for RPE65-LCA patients to a Phase I clinical trial. The University of Pennsylvania leads this collaboration with the University of Florida. PUBLIC HEALTH RELEVANCE: X-linked retinitis pigmentosa (XLRP) caused by mutations in the RPGR gene is among the most severe and common causes of inherited retinal blindness in man. To finalize the development of gene therapy for use in human patients, we will exploit viral vectors already proven effective in preventing or arresting disease in two canine models, and optimize treatments at disease stages comparable to human patients using either subretinal or intravitreal delivery routes.