Vitreal delivery of novel AAV vectors for CNGA3 achromatopsia cone gene therapy

用于 CNGA3 色盲视锥细胞基因治疗的新型 AAV 载体的玻璃体递送

• 批准号: 8702185
• 负责人: Jijing Pang
• 金额: $ 18.38万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8702185
• 关键词: Affect; Aftercare; Age; Animal Model; Area; Behavior; Biodistribution; Bulla; Capsid; Clinical Trials; Complementary DNA; Cone; Data; Defect; Dose; Elements; Exhibits; Functional disorder; GRB10 gene; Gene Delivery; Human; Injection of therapeutic agent; Investigation; Investigational New Drug Application; Lead; Light; Macular degeneration; Mediating; Mus; Mutation; Patients; Performance; Peripheral; Phenylalanine; Photophobia; Property; Publishing; Retina; Retinal; Retinal Cone; Retinal Detachment; Retinal Diseases; Retinitis Pigmentosa; Route; Safety; Staging; Structure; Testing; Therapeutic; Threonine; Toxic effect; Treatment Efficacy; Tyrosine; United States Food and Drug Administration; Valine; Variant; Viral; Vision; Visual; Visual Acuity; achromatopsia; adeno-associated viral vector; animal model selection; base; design; fovea centralis; gene replacement therapy; gene therapy; gene therapy clinical trial; intravitreal injection; mouse model; mutant; novel; public health relevance; response; retinal rods; screening; subretinal injection; success; treatment duration; treatment trial; vector

DESCRIPTION (provided by applicant): We propose to explore ways to use AAV-based gene delivery to restore and/or maintain retinal cone structure, function and vision-dependent behavior. Our overall hypothesis is that appropriately designed, gene-based therapies following intravitreal (IV) injection will be clinically useful for a wide variety of retinal diseases with cne dysfunctions. The need for developing the IV injection option is based on recently published results for 15 patients from the current NEI sponsored LCA2 clinical trial (NCT00481546). Single or multiple subretinal (SR) AAV vector injections resulting in vector blebs that detached the fovea resulted in little or no vision gain for the patient and in some a slight loss in visual acuiy. In contrast, equivalent subretinal vector doses that did not detach the fovea mediated substantial and persistent gains in vision. Therefore, developing alternative ways to more safely transduce foveal cones is the focus of this proposal. To that end, we will test the IV route of vector injection and employ novel AAV variants that we have just developed in an effort to validate and optimize the ability to correct cone defects in a mouse model of achromatopsia 2 without detaching the retina. For this investigation, we will use a mouse model of human achromatopsia with CNGA3 mutations using several novel tyrosine to phenylalanine plus threonine to valine mutant capsid AAV vectors as the gene delivery vehicles for intravitreal injection. Although IV injection of vector can transduce a large area of the inner retina without causing retinal detachment, conventional vectors in the vitreous cannot penetrate the inner retina and transduce rod or cone cells in outer retina. Developing and validating a retina-penetrating property for AAV vectors is therefore a key unmet need in the field and a challenge for current AAV-mediated gene replacement therapy. Another pivotal element of this project is the selection of an animal model that not only possesses a genetically and phenotypically well-characterized cone degeneration, but also has been established to respond well to SR gene-based therapy so that screening these novel AAV vectors for functional and structural cone rescue from the vitreous can be carried out with confidence with reference to an established therapeutic standard. We will therefore focus on a naturally occurring mouse model of human achromatopsia 2 (recessive CNGA3 mutations), the Cpfl5 mouse, that exhibits cone dysfunction/degeneration similar to that seen in humans and responds well to SR AAV vector gene therapy. Therapeutic success in this animal model will provide a template for safer IV treatment trials not only for human achromatopsia but also for other human retinal diseases affecting foveal function such as late stage retinitis pigmentosa, cone and cone/rod dystrophy and potentially macular degeneration.

描述(由申请人提供)：我们建议探索使用基于AAV的基因传递来恢复和/或维持视网膜视锥结构、功能和视觉依赖行为的方法。我们的总体假设是，在玻璃体内注射(IV)后，适当设计的基于基因的治疗方法将在临床上适用于各种伴有CNE功能障碍的视网膜疾病。开发静脉注射方案的必要性是基于最近发表的来自目前NEI赞助的LCA2临床试验(NCT00481546)的15名患者的结果。单次或多次注射视网膜下(SR)AAV载体导致脱离中心凹的载体气泡导致患者很少或根本没有视力增加，在某些情况下，视力略有下降。相比之下，未分离中心凹的等量视网膜下载体剂量可促进视力的显著和持续提高。因此，开发更安全的转导中心凹视锥的替代方法是本提案的重点。为此，我们将测试静脉注射载体的路线，并使用我们刚刚开发的新型AAV变体，以努力验证和优化在不分离视网膜的情况下纠正色视2小鼠模型中视锥缺陷的能力。在这项研究中，我们将使用CNGA3突变的人类色觉障碍小鼠模型，使用几种新的酪氨酸转苯丙氨酸和苏氨酸转缬氨酸突变衣壳AAV载体作为玻璃体内注射的基因载体。虽然静脉注射载体可以在不引起视网膜脱离的情况下对内视网膜进行大面积的转导，但玻璃体中的常规载体不能穿透内视网膜，也不能转导外视网膜中的视杆细胞或视锥细胞。因此，开发和验证AAV载体的视网膜穿透特性是该领域尚未满足的关键需求，也是当前AAV介导的基因替代治疗的挑战。该项目的另一个关键因素是选择了一种动物模型，该动物模型不仅具有良好的遗传学和表型特征的锥体变性，而且已经建立了对基于SR基因的治疗做出良好反应的动物模型，因此，可以参考已建立的治疗标准，筛选这些用于玻璃体功能和结构锥体挽救的新型AAV载体。因此，我们将关注自然发生的人类色盲2(隐性CNGA3突变)小鼠模型Cpfl5小鼠，它表现出与人类相似的视锥功能障碍/变性，并对SR AAV载体基因治疗有良好的反应。该动物模型的治疗成功将为SAFER IV治疗试验提供模板，不仅适用于人类色觉障碍，还适用于其他影响中心凹功能的人类视网膜疾病，如晚期视网膜色素变性、视锥和视锥/视杆细胞营养不良以及潜在的黄斑变性。