Oxidative damage and cone cell death in RP

描述（由申请人提供）：一些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。我们假设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一个很好的治疗策略。在本文中，我们计划探讨超氧化物歧化酶（SOD）的3种异构体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，我们将在高氧和百草枯诱导的视网膜变性两种氧化损伤模型中测试SOD1或3缺乏对光感受器存活的影响。同样的两种模型，以及转基因和自互补腺相关病毒载体（scAAV）介导的基因转移方法，将用于验证SOD 1、2或3表达增加保护光感受器免受氧化损伤的假设。氧化损伤导致RP中锥体细胞死亡的假设将通过测定两种RP小鼠模型中SOD 1、2或3的表达增加是否减少锥体细胞死亡来验证。所有这些小鼠实验的数据将帮助我们选择合适的转基因用于RP转基因猪模型的明确实验。在这些实验中，scaav介导的SOD或SOD组合的基因转移将在零载体上进行测试，以确定SOD的增加是否会减少锥体细胞的死亡。还将比较SOD单独作用与SOD与脑源性神经营养因子（BDNF）共表达的作用，以确定共表达方法是否为锥体存活提供附加益处。这项工作的主要目标是开发一种新的基因疗法来促进RP患者的锥体生存。如果在RP患者中保留视锥细胞的效果得到证实，未来可以测试类似的策略，看看它是否能同时保护AMD患者的视杆细胞和视锥细胞。

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.