Gene Therapy for Retinitis Pigmentosa

色素性视网膜炎的基因治疗

• 批准号: 6618760
• 负责人: RAJENDRA KUMAR-SINGH
• 金额: $ 26.18万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6618760
• 关键词: Adenoviridae; electroretinography; gene therapy; histology; laboratory mouse; nonhuman therapy evaluation; phosphodiesterases; retinitis pigmentosa; sialate; technology /technique development; transfection /expression vector; western blottings

DESCRIPTION (provided by applicant): Retinitis Pigmentosa (RP) is one of the most frequent causes of hereditary blindness in the United States, affecting approximately 1 in every 3000 individuals. There is currently no treatment available for this disease. The broad, long term objectives of this study are to develop a therapy for RP. Some forms of RP in humans, dogs and mice (rd) are caused by mutations in the beta subunit of cGMP phosphodiesterase (bPDE). In order to deliver a normal cDNA encoding bPDE to the rd retina, we have developed a novel class of safer and less-toxic adenovirus vectors termed Encapsidated Adenovirus Minichromosomes - (EAMs or 'gutted' vectors). EAMs have a 36Kb cloning capacity, allowing insertion of large upstream regulatory elements for regulated transgene expression and/or inclusion of multiple therapeutic transgene cassettes. We have used EAMs to temporarily rescue retinal degeneration in rd1 mice by approximately 10 weeks, which would otherwise be complete by 3 weeks postnatal. Our objectives are now focused on extending this short period of rescue to one that might be more therapeutically relevant to humans. EAMs bind to their target cells by attachment of the antenna-like fiber protein to the Coxsackievirus B-adenovirus Receptor (CAR). We have determined that CAR is not significantly expressed on murine and human photoreceptors which could explain the low levels of infection by EAMs and adenovirus vectors. In order to overcome this problem, we propose to modify the structure of EAMs such that they now bind cell surface sialic acid instead of CAR. Sialic acid is abundantly present on the rod cell membrane. We also propose to test adenovirus fibers recently shown to have significantly enhanced tropism for neurons. We will use these improved EAMs to deliver bPDE to the rd10 retina. We will measure therapeutic effects on photoreceptors by PDE assays, histology, electroretinograms and western analysis. Upon completion of this study, we will have constructed and tested a vector which will have potential use in a Phase 1 clinical trial for treatment of RP in humans.

描述（由申请人提供）：在美国，色素性视网膜炎（RP）是遗传性失明最常见的原因之一，大约每3000人中就有1人受到影响。目前还没有治疗这种疾病的方法。这项研究的广泛、长期目标是开发一种治疗RP的方法。人类、狗和小鼠的某些形式的RP （rd）是由cGMP磷酸二酯酶(bPDE) β亚基突变引起的。为了将编码bPDE的正常cDNA传递到rd视网膜，我们开发了一类更安全、毒性更低的新型腺病毒载体，称为封装腺病毒小染色体（EAMs或“去肠”载体）。eam具有36Kb的克隆能力，允许插入大的上游调控元件来调控转基因表达和/或包含多个治疗性转基因磁带。我们已经使用EAMs在大约10周内暂时挽救rd1小鼠的视网膜变性，否则将在出生后3周完成。我们现在的目标是将这个短暂的拯救期延长到一个可能与人类治疗更相关的时间。EAMs通过将天线状纤维蛋白附着在柯萨奇病毒b腺病毒受体（CAR）上与靶细胞结合。我们已经确定，CAR在小鼠和人的光感受器上不显着表达，这可以解释EAMs和腺病毒载体的低水平感染。为了克服这个问题，我们建议修改eam的结构，使它们现在结合细胞表面唾液酸而不是CAR。唾液酸大量存在于杆状细胞膜上。我们也建议测试腺病毒纤维最近显示有显著增强神经元的倾向性。我们将使用这些改进的eam将bPDE传递到rd10视网膜。我们将通过PDE测定、组织学、视网膜电图和western分析来测量对光感受器的治疗效果。在这项研究完成后，我们将构建并测试一种载体，该载体将有可能用于治疗人类RP的1期临床试验。