Using Nanotechnology to Rescue Visual Loss in A Model of Human Blinding Disorder

描述(申请人提供)：黄斑变性(MD)是一组遗传性视网膜疾病，其特征是视网膜黄斑区锥形感光细胞死亡。在MD患者中发现突变的基因中，外周蛋白/rds(P/rds)是突变较多的基因。到目前为止，已发现有30多种不同的P/rds基因突变与MD有关，其中R172W突变是MD患者中最常见的突变。我们建立了一种锥体显性变性的转基因小鼠模型，在该模型中，小鼠在视杆细胞和视锥细胞中都表达R172W P/rds。这些小鼠的表型与携带相同突变的患者的症状相似，功能、结构和生化分析表明，转基因表达水平与这些小鼠的锥体变性的开始/严重程度直接相关。目前还没有临床上可以接受的治疗MD和视锥细胞杆营养不良的方法。作为第一个与P/rds突变相关的锥体显性变性的小鼠模型，R172W小鼠为研究锥体退行性疾病的治疗提供了一个有价值的工具。最近的临床前和临床试验显示，基因替代疗法有望用于遗传性基因缺陷性疾病。致密的DNA纳米颗粒传递作为一种新的、非病毒的方法，已经被证明能够介导有效的治疗性基因转移和表达。该建议旨在利用R172W小鼠模型，探索DNA纳米颗粒改善P/RDS相关性MD和视锥-杆状营养不良自然病史的治疗潜力。首先，我们将评估DNA纳米颗粒视网膜下注射后转基因P/rds基因在野生型小鼠体内的光感受器表达。视网膜下注射后的毒性和炎症反应将从形态和生化角度进行评估。其次，我们将评估纳米基因传递对R172W小鼠视锥显性退行性变的挽救作用。我们假设R172W小鼠的退变表型将通过P/rds纳米颗粒的替代输送而被挽救或部分挽救。从这项研究中获得的信息将为视网膜变性的治疗干预开辟新的途径，并将对人类视网膜疾病的临床治疗产生重大影响。

DESCRIPTION (provided by applicant): Macular degeneration (MD) is a group of inherited retinal diseases characterized by the death of cone photoreceptor cells in the macular region of the retina. Among the genes in which mutations have been identified in patients with MD, peripherin/rds (P/rds) is the one with a large number of mutations. To date, more than thirty different mutations in the P/rds gene have been identified to associate with MD and the R172W mutation is the most common one identified in MD patients. We have established a transgenic mouse model of cone-dominant degeneration in which mice express R172W P/rds in both rods and cones. The phenotype of the mice resembles the symptoms in patients carrying the same mutation and functional, structural and biochemical analyses showed a direct correlation between transgene expression levels and the onset/severity of the cone degeneration in these mice. There are currently no clinically acceptable treatments available for MD and cone-rod dystrophy. As the first mouse model of cone-dominant degeneration associated with P/rds mutation, the R172W mice provide a valuable tool to study the treatment of cone degenerative diseases. Recent pre-clinical and clinical trials have shown promise of gene replacement therapy in the inherited gene-deficient diseases. The compacted DNA nanoparticle delivery, as a novel, non-viral approach, has been shown to mediate efficient therapeutic gene transfer and expression. This proposal is aimed to explore the therapeutical potential of DNA nanoparticles to improve the natural history of P/rds-associated MD and cone-rod dystrophy, using R172W mouse model. First, we will evaluate the photoreceptor expression of P/rds transgene in the wild-type mice following subretinal delivery of the DNA nanoparticles. The toxicity and inflammatory responses following the subretinal injection will be evaluated for both morphological and biochemical perspectives. Secondly, we will assess the rescue of the cone-dominant degeneration in R172W mice by the nanoparticle gene delivery. We hypothesize that the degenerative phenotype in R172W mice will be rescued or partially rescued by replacement delivery of the P/rds nanoparticles. Information obtained from the proposed study will open a new pathway for therapeutic interventions of retinal degeneration and will have significant impact on the clinical treatment of human retinal diseases.