Novel model systems for the study of cone disorders and other heritable retinal diseases

项目总结/摘要 视网膜变性疾病是全球无法治愈的失明的常见原因，影响数百万人的生活。 FDA唯一批准的治疗这些疾病的方法是基因治疗特定的RPE 65突变，导致利伯氏先天性黑蒙和视网膜色素变性。 开发有效疗法的一个主要限制是使用不能很好地复制人类状况的模型系统。特别是对于视锥细胞疾病，使用具有视杆细胞占主导地位的视网膜并且没有真正的黄斑的模型系统的研究具有实质性的局限性。我们建议开发一系列新颖的和自发的人类遗传性视网膜疾病的动物模型。在初步分析中，我们已经确定了一个新的自发模型直接相关的人类视网膜疾病。基因测试发现了四个纯合的个体，他们在PDE 6C基因中天然存在破坏性突变，该突变此前与人类视锥细胞营养不良有关。对PDE 6C突变纯合子动物进行的暗视和明视全视野视网膜电图显示了相对正常的视杆细胞反应，但无视锥细胞反应。通过眼底照相、蓝色自体荧光和荧光素血管造影以及同时使用光谱域光学相干断层扫描的黄斑中心凹变薄来确定轻微但特征性的视网膜病变。我们的遗传调查还确定了其他7种人类视网膜疾病基因突变的个体，这些基因突变预计会严重损害基因或蛋白质功能，从而指出可能的其他新模型。 为了开发PDE 6C视锥细胞营养不良的新模型，并使该模型和其他新模型可用于视觉研究界，我们提出了四个具体目标：1）通过DNA测序鉴定和遗传表征人类视网膜疾病的新动物模型，2）对视网膜疾病的新模型进行完整的眼科表型分析，3）繁殖具有PDE 6C视锥营养不良的动物群体，和4）在具有PDE 6C视锥营养不良突变的这些受试者中比较基于细胞的疗法和基因替代疗法。 这项工作的成功完成将产生一个具有良好特征的遗传性视锥细胞营养不良的新动物模型，与现有模型相比，该模型与人类疾病具有更大的相似性，从而为后续的人体试验提供更好的翻译。 此外，受影响的动物将提供给更广泛的视觉研究界，并将确定具有类似潜力的其他新模型。

Project Summary/Abstract Retinal degeneration diseases are a common cause of untreatable blindness worldwide, affecting the lives of millions. The only FDA-approved treatment for these disorders is gene therapy for specific RPE65 mutations that cause Leber’s congenital amaurosis and retinitis pigmentosa. One major limitation to the development of effective therapies is the use of model systems that poorly replicate the human condition. Particularly for cone disorders, studies that use model systems with a rod-dominant retina and no true macula have substantive limitations. We propose to develop a series of novel and spontaneous animal models of human inherited retinal diseases. In preliminary analyses, we have identified a new spontaneous model directly relevant to human retinal disease. Genetic testing identified four individuals homozygous for a naturally occurring damaging mutation in the PDE6C gene, which has previously been associated with cone dystrophy in humans. Scotopic and photopic full-field electroretinograms performed on animals homozygous for the PDE6C mutation demonstrated a relatively normal rod response but no cone response whatsoever. A subtle but characteristic retinopathy was identified using fundus photography, blue autofluorescence, and fluorescein angiography with concurrent foveal thinning using spectral-domain optical coherence tomography. Our genetic survey also identified individuals with mutations in 7 other human retinal disease genes that are predicted to severely damage gene or protein function, pointing to possible additional new models. To develop the new model of PDE6C cone dystrophy, and make this and other new models available to the vision research community, we propose four Specific Aims: 1) to identify and genetically characterize new animal models of human retinal disease via DNA sequencing, 2) to perform complete ophthalmic phenotyping of the new models of retinal disease, 3) to breed a colony of animals with PDE6C cone dystrophy and 4) to compare cell-based and gene replacement therapies in these subjects with PDE6C cone dystrophy mutations. Successful completion of this work will produce a well-characterized new animal model of inherited cone dystrophy with significantly greater similarity to human disease than existing models, thus providing substantially better translation to subsequent human trials. In addition, affected animals will be made available to the wider vision research community, and other new models with similar potential will be identified.