Oxidative Damage and Cone Cell Death in RP

描述（由申请人提供）：视网膜色素变性（RP）是一组疾病，其中数百种不同突变中的一种导致视杆细胞死亡，导致夜盲症，随后视锥细胞逐渐死亡，导致视野收缩，最终失明。杆的损失导致外视网膜中的氧水平升高，并且在当前的资助期间，我们证明了这伴随着锥细胞中的进行性氧化损伤，导致功能降低和细胞死亡。使用转基因的方法，我们证明了内源性抗氧化防御系统的组件在RP小鼠模型中的过表达可以减少氧化损伤，促进视锥细胞的功能和生存，但只有当有一个超氧化物歧化酶（SOD）和H2 O2解毒酶的线粒体或细胞质中的共表达。这表明在RP的情况下，在细胞溶质和线粒体中存在过量的活性氧（ROS），并且还表明为了利用ROS解毒酶来治疗RP，将需要多基因转移。我们开始将我们的发现转化为基于基因的RP治疗，通过鉴定在小鼠或猪中视网膜下或玻璃体内注射后转导光感受器的病毒载体/启动子组合，并且我们在RP的小鼠和猪模型中开始了治疗性转基因的研究。在下一个资助期间，我们使用定量技术来评估多基因转移对单个组分转基因表达的影响。我们将继续我们目前的实验，在小鼠和猪模型的RP，将回答是否有针对性的线粒体或细胞质与多基因转移提供更大的锥救援。最后，我们将确定是否同时靶向线粒体和胞质隔室提供更好的结果比单独靶向任何一个。这项提案的潜在影响很大，因为它将 提供关于多基因转移的重要新信息，这将使基因治疗领域的所有研究者感兴趣，并且最重要的是将提供可能导致临床试验的RP的大型动物模型中的关键功效数据。 公共卫生相关性：该项目旨在开发一种基于基因的治疗方法，通过增强内源性抗氧化防御系统来预防视网膜色素变性（RP）患者的视锥细胞死亡。RP是一组疾病，其中数百种不同的突变导致视杆细胞死亡，随后对视锥细胞进行性氧化损伤并最终失明。这种靶向视锥细胞的治疗将适用于所有RP患者，无论潜在的突变如何，因此可以弥补大量未满足的医疗需求，提供重大的公共卫生影响。

DESCRIPTION (provided by applicant): Retinitis pigmentosa (RP) is a group of diseases in which one of hundreds of different mutations leads to death of rods resulting in night blindness followed by gradual death of cones causing constriction of visual fields and eventual blindness. The loss of rods results in elevated levels of oxygen in the outer retina and during the current grant period, we demonstrated that this is accompanied by progressive oxidative damage in cones causing reduced function and cell death. Using a transgenic approach, we demonstrated that over-expression of components of the endogenous antioxidant defense system in mouse models of RP can reduce oxidative damage and promote cone function and survival, but only if there is co- expression of a superoxide dismutase (SOD) and a H2O2-detoxifying enzyme in mitochondria or in the cytosol. This suggests that in the setting of RP, there are excessive reactive oxygen species (ROS) in both the cytosol and mitochondria and also indicates that in order to utilize ROS-detoxifying enzymes to treat RP, multi- gene transfer will be needed. We began translating our findings into a gene-based therapy for RP by identifying a viral vector/promoter combination that transduces photoreceptors after subretinal or intravitreous injections in mice or pigs and we initiated studies with therapeutic transgenes in mouse and pig models of RP. During the next grant period we use quantitative techniques to assess the effect of multi- gene transfer on the expression of individual component transgenes. We will continue our current experiments in both mouse and pig models of RP that will answer whether targeting the mitochondria or cytosol with multi-gene transfer provides greater cone rescue. Finally we will determine whether targeting both the mitochondrial and cytosolic compartments provides better outcomes than targeting either alone. The potential impact of this proposal is high because it will provide important new information regarding multi-gene transfer that will interest all investigator in the gene therapy field, and most importantly will provide critical efficacy data in a large animl model of RP that could lead to clinical trials. PUBLIC HEALTH RELEVANCE: This project seeks to develop a gene-based treatment to prevent cone cell death in patients with retinitis pigmentosa (RP) by augmenting the endogenous antioxidant defense system. RP is a group of diseases in which hundreds of different mutations lead to rod cell death followed by progressive oxidative damage to cones and eventual blindness. This treatment which targets cones will apply to all patients with RP regardless of the underlying mutation and therefore could remedy a large unmet medical need providing major public health impact.