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

描述（由申请人提供）：黄斑变性（Macular degeneration， MD）是一组遗传性视网膜疾病，其特征是视网膜黄斑区域的视锥细胞死亡。在MD患者中已发现突变的基因中，外周蛋白/rds （P/rds）是突变数量最多的基因。迄今为止，已经鉴定出30多种与MD相关的P/rds基因突变，其中R172W突变是MD患者中最常见的突变。我们建立了一种转基因小鼠锥体显性变性模型，小鼠在杆状体和锥体中均表达r172wp /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、结构和生化分析显示，转基因表达水平与这些小鼠的锥体变性的发病/严重程度之间存在直接相关性。目前临床上还没有可接受的治疗MD和锥杆营养不良的方法。R172W小鼠作为首个与P/rds突变相关的锥体显性变性小鼠模型，为研究锥体退行性疾病的治疗提供了有价值的工具。最近的临床前和临床试验显示，基因替代疗法有望治疗遗传性基因缺陷疾病。紧凑的DNA纳米颗粒递送，作为一种新的，非病毒的方法，已被证明介导有效的治疗性基因转移和表达。本研究旨在利用R172W小鼠模型，探索DNA纳米颗粒在改善P/rds相关MD和锥杆营养不良的自然史方面的治疗潜力。首先，我们将评估野生型小鼠视网膜下递送DNA纳米颗粒后P/rds转基因光感受器的表达。视网膜下注射后的毒性和炎症反应将从形态学和生化角度进行评估。其次，我们将评估纳米颗粒基因递送对R172W小鼠锥体显性变性的拯救作用。我们假设通过P/rds纳米颗粒的替代递送，R172W小鼠的退行性表型将被拯救或部分拯救。本研究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.