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: 8555123
• 负责人: Jijing Pang
• 金额: $ 22.36万
• 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 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8555123
• 关键词: Affect; Aftercare; Age; Animal Model; Area; Behavior; Biodistribution; Bulla; Capsid; Clinical Trials; Complementary DNA; 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）：我们提出探索使用基于AAV的基因递送来恢复和/或维持视网膜锥结构、功能和视觉依赖性行为的方法。我们的总体假设是，玻璃体内（IV）注射后适当设计的基于基因的治疗将在临床上适用于各种各样的视网膜疾病与cne功能障碍。开发IV注射选项的必要性是基于最近发表的来自当前NEI申办的LCA 2临床试验（NCT 00481546）的15例患者的结果。单次或多次视网膜下（SR）AAV载体注射导致脱离中央凹的载体泡，导致患者的视力几乎没有或没有增加，并且在一些情况下导致视力的轻微损失。相比之下，不分离中央凹的等效视网膜下载体剂量介导了视觉的实质性和持续性增益。因此，开发更安全的视网膜中央凹锥的替代方法是本提案的重点。为此，我们将测试载体注射的IV途径，并采用我们刚刚开发的新型AAV变体，以验证和优化在不分离视网膜的情况下纠正色盲2小鼠模型中的视锥缺陷的能力。对于这项研究，我们将使用CNGA 3突变的人色盲小鼠模型，使用几种新的酪氨酸-苯丙氨酸加苏氨酸-缬氨酸突变衣壳AAV载体作为玻璃体内注射的基因递送载体。虽然IV注射载体可以覆盖大面积的内层视网膜而不引起视网膜脱离，但玻璃体中的常规载体不能穿透内层视网膜和外层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中未满足的关键需求，也是当前AAV介导的基因替代疗法的挑战。该项目的另一个关键要素是选择动物模型，该动物模型不仅具有遗传和表型上充分表征的视锥变性，而且已经建立对基于SR基因的治疗反应良好，使得可以参照建立的治疗标准有信心地进行这些新的AAV载体的功能和结构视锥从玻璃体中的拯救。因此，我们将集中于人类色盲2（隐性CNGA 3突变）的天然存在的小鼠模型，Cpf 15小鼠，其表现出与在人类中观察到的类似的视锥细胞功能障碍/变性，并且对SR AAV载体基因治疗反应良好。该动物模型的治疗成功将为更安全的IV治疗试验提供模板，不仅用于人类全色盲，还用于影响中央凹功能的其他人类视网膜疾病，如晚期视网膜色素变性、视锥和视锥/视杆营养不良和潜在的黄斑变性。