Understanding How Photoswitches Restore Visual Function in Blind Mice

 描述（由申请人提供）：视网膜色素变性（RP）和年龄相关性黄斑变性（AMD）是由视杆细胞和视锥细胞变性引起的致盲性疾病，使视觉系统的其余部分完好无损，但无法对光作出反应。一种名为DENAQ的合成化学光开关可以恢复RP盲小鼠模型的视觉反应。先前的研究表明，DENAQ赋予视网膜神经节细胞（RGC）动作电位放电的光敏感性，但这是如何发生的尚不清楚。该项目的目标是阐明DENAQ光敏化的机制，这对于发现改进的候选药物和优化视力恢复的光刺激策略至关重要。第一个目的是理解为什么DENAQ选择性地光敏化来自具有死亡的视杆和视锥的小鼠的视网膜，而对具有完整的视杆和视锥的健康视网膜没有影响。我们将测试的假设，变性导致增强进入RGCs的DENAQ和/或增强作用的离子通道在RGCs自发放电。第二个目的是确定哪些RGC被DENAQ光敏化。在健康的视网膜中，一些RGC在光开始时发射，一些在偏移时发射，以及一些在开始和偏移时发射。研究将确定哪些被DENAQ光敏化，以及视杆细胞和视锥细胞的局部变性是否导致空间受限的RGC光敏化，这与AMD（一种局部变性疾病）特别相关。其他研究将揭示DENAQ光敏化是否适用于手术视网膜切除术期间获得的组织样本中的人类RGC。第三个目标是利用我们的发现来优化视力恢复。有关DENAQ靶向离子通道的信息将使开发更具体的光开关成为可能。这些通道在RGC中的亚细胞定位将使空间上更精确的光控制成为可能。最后，体内成像研究将揭示从DENAQ处理的视网膜传输到盲小鼠大脑的信号，验证视觉系统的功能完整性，并提供优化视网膜刺激模式的平台，以最好地再现正常的视觉反应。

 DESCRIPTION (provided by applicant): Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are blinding diseases caused by the degeneration of rods and cones, leaving the rest of the visual system intact but unable to respond to light. A synthetic chemical photoswitch, named DENAQ, can restore visual responses in blind mouse models of RP. Previous studies showed that DENAQ imparts light-sensitivity on action potential firing in retinal ganglion cells (RGC), but how this occurs is unclear. The goal of this project is to elucidate the mechanism of DENAQ photosensitization, crucial for enabling discovery of improved drug candidates and for optimizing photo- stimulation strategies for vision restoration. The first aim i to understand why DENAQ selectively photosensitizes retinas from mice with dead rods and cones while having no effect on healthy retinas with intact rods and cones. We will test the hypothesis that degeneration leads to enhanced entry of DENAQ into RGCs and/or enhanced action on ion channels underlying spontaneous firing in RGCs. The second aim is to identify which RGCs are photosensitized by DENAQ. In the healthy retina, some RGCs fire at light onset, some at offset, and some at onset and offset. Studies will determine which are photosensitized by DENAQ, and whether local degeneration of rods and cones leads to spatially constrained RGC photosensitization, of particular relevance for AMD, a localized degenerative disease. Other studies will reveal whether DENAQ photosensitization applies to human RGCs in tissue samples obtained during surgical retinectomy. The third aim is to exploit our findings to optimize vision restoration. Information about the ion channels targeted by DENAQ will enable development of more specific photoswitches. Subcellular localization of these channels in RGCs will enable more spatially-precise photo-control. Finally imaging studies in vivo will reveal signals transmitted from the DENAQ-treated retina to the brain of blind mice, validating the functional integrity of the visual system and providing a platform for optimizing retinal stimulatin patterns to best recapitulate normal visual responses.