Understanding how photoswitches restore visual function in blindness

项目总结 视网膜色素变性(RP)和老年性黄斑变性(AMD)是由 视杆细胞和视锥细胞退化，使视觉系统的其余部分完好无损，但不能对光做出反应。一个 名为DENAQ的合成化学光开关可以恢复RP盲鼠模型的视觉反应。 以前的研究表明，DENAQ对视网膜神经节细胞的动作电位放电具有光敏性 (RGC)，但这是如何发生的尚不清楚。本项目的目的是阐明DENAQ的作用机制 光敏化，对于发现改进的候选药物和优化光敏化至关重要 视力恢复的刺激策略。第一个目标是理解为什么DENAQ选择性地 用死视杆和视锥细胞使小鼠的视网膜光敏，而对健康的视网膜没有影响 完整的杆状和圆锥体。我们将检验退化导致DENAQ进入增强的假说 视网膜节细胞和/或增强视网膜节细胞自发放电的离子通道的作用。第二个目标是 确定哪些RGC被DENAQ光敏。在健康的视网膜中，一些视网膜节细胞在光线开始时激发，一些视网膜节细胞 在偏移量，以及一些在起点和偏移量。研究将确定哪些是DENAQ感光的，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 与AMD尤其相关，AMD是一种局限性退行性疾病。其他研究将揭示DENAQ是否 光敏作用适用于在手术视网膜切除术期间获得的组织样本中的人视网膜神经节细胞。第三 目的是利用我们的发现来优化视力恢复。有关目标离子通道的信息 DENAQ将使开发更具体的光开关成为可能。这些通道在脑内的亚细胞定位 RGC将实现更精确的空间照片控制。最后，体内成像研究将揭示信号 从DENAQ治疗的视网膜传输到盲鼠的大脑，验证了 视觉系统，并提供优化视网膜刺激模式以最佳概括正常状态的平台 视觉反应。

PROJECT SUMMARY 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 is 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 stimulation patterns to best recapitulate normal visual responses.