Oxidative damage and cone cell death in RP

描述（由申请人提供）：几条证据表明，氧化损伤在年龄相关性黄斑变性（AMD）的发病机制中起作用。我们推测氧化损伤在视网膜色素变性（RP）的视锥细胞死亡中也起重要作用。如果这是真的，增加光感受器中抗氧化酶的表达可能是这两种疾病过程中的良好治疗策略。本研究拟探讨超氧化物歧化酶（SOD）的3种亚型在光感受器氧化防御系统中的作用。为了评估内源性SOD的作用，将在两种氧化损伤模型（高氧和百草枯诱导的视网膜变性）中测试SOD 1或3缺乏对光感受器存活的影响。相同的两种模型，沿着转基因和自身互补腺相关病毒载体（scAAV）介导的基因转移方法，将用于检验SOD 1、2或3表达增加保护光感受器免受氧化损伤的假设。将通过确定在两种RP小鼠模型中SOD 1、2或3的表达增加是否减少视锥细胞死亡来检验氧化损伤有助于RP中视锥细胞死亡的假设。来自小鼠中所有这些实验的数据将帮助我们选择合适的转基因用于RP转基因猪模型中的确定性实验。在那些实验中，将针对无效载体测试SOD或SOD组合的scAAV介导的基因转移，以确定SOD的产生增加是否减少视锥细胞死亡。还将单独的SOD的作用与SOD与脑源性神经营养因子（BDNF）的共表达进行比较，以确定共表达方法是否为视锥细胞存活提供附加益处。这项工作的主要目标是开发一种新的基因疗法，以促进RP患者的视锥细胞存活。如果证明在RP患者中保留视锥细胞的益处，将来可以测试类似的策略，以观察其是否保护AMD患者的视杆细胞和视锥细胞。 这项研究解决了美国的一个主要公共卫生问题，即遗传性视网膜变性，目前还没有有效的治疗方法。此外，该结果也可能适用于AMD，这是60岁以上美国人严重视力丧失的最常见原因。

DESCRIPTION (provided by applicant): Several lines of evidence suggest that oxidative damage plays a role in the pathogenesis of age-related macular degeneration (AMD). We hypothesize that oxidative damage also plays an important role in cone cell death in retinitis pigmentosa (RP). If this is true, increased expression of antioxidant enzymes in photoreceptors may be a good therapeutic strategy in both disease processes. In this proposal, we plan to explore the role of the 3 isoforms of superoxide dismutase (SOD) in the oxidative defense system of photoreceptors. To assess the role of endogenous SODs, the effect of deficiency of SOD1 or 3 on photoreceptor survival will be tested in two models of oxidative damage, hyperoxia- and paraquat-induced retinal degeneration. The same two models, along with transgenic and self-complementary adeno- associated viral vector (scAAV)-mediated gene transfer approaches, will be used to test the hypothesis that increased expression of SOD 1, 2, or 3 protects photoreceptors from oxidative damage. The hypothesis that oxidative damage contributes to cone cell death in RP will be tested by determining if increased expression of SOD 1, 2, or 3 reduces cone cell death in two mouse models of RP. The data from all of these experiments in mice will help us to select the appropriate transgene(s) for definitive experiments in a transgenic pig model of RP. In those experiments scAAV-mediated gene transfer of an SOD or combination of SODs will be tested against null vector to determine if increased production of SOD(s) reduces cone cell death. The effects of SOD(s) alone will also be compared to co-expression of SOD(s) with brain-derived neurotrophic factor (BDNF) to determine if the co-expression approach provides additive benefit for cone survival. The major goal of this work is to develop a new gene therapy to promote cone survival in patients with RP. If benefit is demonstrated in preserving cones in patients with RP, a similar strategy could be tested in the future to see if it protects both rods and cones in patients with AMD. This study addresses a major public health problem in the US, inherited retinal degenerations, for which there is currently no effective treatment. In addition, the results may also be applicable to AMD, the most prevalent cause of severe vision loss in Americans over the age of 60.