Achromatopsia - Disease Mechanisms and Cone-Directed Gene Therapy

全色盲 - 疾病机制和视锥细胞定向基因治疗

• 批准号: 8446968
• 负责人: Andras Komaromy
• 金额: $ 39.85万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8446968
• 关键词: Affect; Age related macular degeneration; Age-Years; Anatomy; Animal Model; Biogenesis; Biological Preservation; Blindness; Canis familiaris; Catalytic RNA; Color; Color Visions; Complementary DNA; Data; Defect; Development; Disease; Disease model; Evaluation; Eye; Functional disorder; Gene Expression; Gene Proteins; Generic Drugs; Genomics; Goals; Health; Hereditary Disease; Human; Inherited; Lead; Life; Mediating; Metric; Missense Mutation; Modality; Modeling; Molecular; Monitor; Mus; Mutation; Patients; Pattern; Phase I Clinical Trials; Phenotype; Photoreceptors; Process; Proteins; Publishing; Rattus; Recombinant adeno-associated virus (rAAV); Reporting; Research Proposals; Retina; Retinal; Retinal Cone; Retinal Diseases; Retinitis Pigmentosa; Rodent Model; Safety; Specificity; Staging; Structure; Structure of retinal pigment epithelium; Testing; Therapeutic; Time; Tissues; Toxic effect; Transgenes; Translations; Treatment outcome; Vision; Visual Acuity; achromatopsia; adeno-associated viral vector; age effect; base; cyclic-nucleotide gated ion channels; design; disease phenotype; early onset; gain of function mutation; gene replacement; gene replacement therapy; gene therapy; improved; loss of function mutation; man; monolayer; mutant; neurotrophic factor; prevent; promoter; public health relevance; restoration; success; transgene expression; visual performance

DESCRIPTION (provided by applicant): Cone photoreceptors are responsible for central visual acuity, color vision, and photopic vision and are therefore critical for visual performance in daily human life. As such, it is of utmost importance to target cones when designing therapeutic treatment for retinal diseases such as achromatopsia, cone dystrophies, and cone-rod dystrophies that primarily affect cones. However, cone rescue is of even greater importance in diseases where cones are affected secondarily, such as in retinitis pigmentosa (RP) and most forms of age-related macular degeneration (AMD), the leading cause of vision loss in people over 65 years of age. The overarching aim of this proposal is to develop 2 natural canine achromatopsia models as a platform for recombinant adeno-associated virus (rAAV)-mediated cone-directed gene therapy. In both canine models, loss-of-function mutations in the cone cyclic nucleotide-gated channel beta subunit (CNGB3) lead to a disease phenotype identical to human achromatopsia. Mutations in CNGB3 are the most common cause for achromatopsia in man, making the 2 canine strains the optimal animal model in which to carry out cone-targeted gene replacement studies with translational potential. The long-term success of rAAV-mediated retinal gene therapy for primary defects of the retinal pigment epithelium (RPE) has been demonstrated in several species, including dogs. Because of their successful, stable, and apparently safe transgene expression, these studies are now in Phase 1 clinical trials. In contrast to RPE defects, the treatment of primary photoreceptor diseases is more difficult, and previous gene therapy studies have shown variable success. The hypothesis to be tested in this proposal is that cone function and structure can be restored, and degeneration prevented, using rAAV-mediated cone-directed delivery of wildtype CNGB3 cDNA under control of cone-specific promoters. To test this hypothesis, we specifically propose to 1) optimize rAAV vectors for targeted gene expression in cones and 2) maximize preservation of cone function following cone-specific expression of CNGB3 cDNA in the two canine models. Results from the first two aims will provide data regarding the efficiency, safety, and limitations of the treatment. In the final aim, functional, structural, and molecular disease correlates of the canine CNGB3 mutations will be characterized and their potential reversal following successful gene therapy assessed in order to more fully understand disease mechanisms and to provide disease metrics for establishing an optimal therapeutic time window. The canine achromatopsia models offer unique opportunities for proof-of-principle of cone-directed gene therapy and for eventual translation to patients.

描述（由申请人提供）：锥状光感受器负责中央视觉灵敏度，色觉和光视觉，因此对人类日常生活中的视觉表现至关重要。因此，在设计主要影响视锥细胞的视网膜疾病（如色盲、视锥细胞营养不良和视锥杆营养不良）的治疗方法时，以视锥细胞为靶点是至关重要的。然而，对于继发影响视锥细胞的疾病，如色素性视网膜炎（RP）和大多数形式的老年性黄斑变性（AMD），视锥细胞的抢救更为重要。老年性黄斑变性是65岁以上人群视力丧失的主要原因。本研究的主要目的是建立2种天然犬色盲模型，作为重组腺相关病毒（rAAV）介导的锥体基因治疗平台。在这两种犬模型中，锥体环核苷酸门控通道β亚基（CNGB3）的功能丧失突变导致与人类色盲相同的疾病表型。CNGB3突变是人类色盲最常见的原因，这使得这两种犬系成为开展具有翻译潜力的锥体靶向基因替代研究的最佳动物模型。raav介导的视网膜基因治疗视网膜色素上皮（RPE）原发性缺陷的长期成功已经在包括狗在内的几个物种中得到证实。由于它们的成功、稳定和明显安全的转基因表达，这些研究现在处于1期临床试验。与RPE缺陷相比，原发性光感受器疾病的治疗更加困难，先前的基因治疗研究显示出不同的成功。本研究的假设是，在锥体特异性启动子的控制下，利用raav介导的锥体定向递送野生型CNGB3 cDNA，可以恢复锥体的功能和结构，防止锥体退化。为了验证这一假设，我们特别提出：1)优化rAAV载体，以在锥体中靶向表达基因；2)在两种犬模型中，在锥体特异性表达CNGB3 cDNA后，最大限度地保留锥体功能。前两个目标的结果将提供有关治疗的有效性、安全性和局限性的数据。在最终目标中，犬CNGB3突变的功能、结构和分子疾病相关因素将被表征，并在成功的基因治疗后评估其潜在的逆转，以便更充分地了解疾病机制，并为建立最佳治疗时间窗提供疾病指标。犬色盲模型提供了独特的机会，证明锥体定向基因治疗的原理，并最终翻译到患者。