Photosensitive control of the inner retina

描述（由申请人提供）：我们提出将光敏性直接赋予患病视网膜中的正常非光敏神经元。虽然遗传性视网膜变性的根源有许多遗传原因，但一个共同的主题是感光细胞的最终凋亡。在大多数情况下，剩余的内部视网膜神经元在杆和锥丢失后存活很长时间。我们目标的核心是使用新型视紫红质，允许用可见光精确控制神经活动。视紫红质-2是一种光敏阳离子通道，允许神经兴奋响应蓝光。一种功能性的匡威是盐视紫红质，它是一种光敏的氯离子泵，在黄光下可以抑制神经活动.这些视紫红质使用类维生素A作为其发色团，并直接调节活性，无需辅助蛋白质级联或外源化学物质。我们假设，如果在适当的细胞亚型中启动，光驱动的激发和抑制可以重新创建正常存在于视网膜中的ON和偏离中心的视觉信息流。这些平行的信息流主要负责实现对比敏感度和高敏锐度。特异性递送到所需的ON或偏离中心的细胞群体是不平凡的，我们建议通过结合转录靶向沿着病毒基因转移方法来实现这一点。膜片钳电生理学与光栅扫描刺激相结合将是该项目的组成部分，用于评估转基因靶向的特异性和表征这些神经元网络产生的光电流。最后，我们希望了解在疾病模型中，光敏内层视网膜是否可以通过简单的行为工具将功能信息传递到更高的视觉中心。使用这些组合的神经工程和电生理学方法，我们的目标是确定是否选择性的光激发和ON和OFF通路的内部神经元的抑制可以赋予有用的光敏感性受伤的视网膜。公共卫生相关性：基因治疗是一种非常有前途的方法，试图恢复视力的疾病，导致感光细胞损失，并赋予光敏感性直接存活的视网膜神经元可能是一种方法。我们希望了解将非光敏神经元转化为光传感器的潜力，并将这些知识应用于视网膜假体的未来开发。

DESCRIPTION (provided by applicant): We propose to impart light sensitivity directly onto normally non-photosensitive neurons in a diseased retina. While inherited retinal degenerations have many genetic causes at their source, one common theme is the eventual apoptotic death of photoreceptor cells. In most cases, the remaining inner retinal neurons survive long after rods and cones are lost. Central to our goal is the use of novel rhodopsins that allow for precise optical control of neural activity with visible light. Channelrhodopsin-2 is a photosensitive cation channel that allows for neural excitation in response to blue light. A functional converse is Halorhodopsin, a photo- sensitive chloride pump that silences neural activity with yellow light. These rhodopsins use retinoids as their chromophore and directly modulate activity without accessory protein cascades or exogenous chemicals. We hypothesize that if initiated in the appropriate cell subtype, light-driven excitation and inhibition may re- create the ON and OFF-center visual information streams normally present in the retina. These parallel information streams are largely responsible for allowing contrast sensitivity and high acuity. Specific delivery to the desired ON or OFF-center cell population is not trivial, and we propose to approach this by a combination of transcriptional targeting along with viral gene transfer methods. Patch clamp electrophysiology combined with raster scanning stimuli will be integral to the project for both evaluating the specificity of transgene targeting and in characterizing the photocurrents generated from networks of these neurons. Finally, we hope to understand if a photosensitive inner retina can transmit functional information to higher visual centers in a disease model with simple behavioral tools. Using these combined neuroengineering and electrophysiological approaches, we aim to determine if selective photo-excitation and inhibition of ON and OFF pathway inner neurons can confer useful light sensitivity to the injured retina. PUBLIC HEALTH RELEVANCE: Gene therapy is a highly promising method for attempting to restore vision in diseases that cause photoreceptor loss, and imparting light sensitivity directly to surviving retinal neurons may be one approach. We hope to understand the potential for converting non-photosensitive neurons into photosensors and apply this knowledge toward the future development of a retinal prosthetic.