Expression of genetically encoded photosensors in retinal bipolar neurons

描述（由申请人提供）：视网膜的感光细胞执行将光转化为电信号的基本任务，该电信号可以传递并由视觉系统的其余部分分析。导致感光细胞退化的疾病会导致不可逆的失明，因为视网膜的剩余神经元对光不敏感，因此无法替代感光细胞的损失。拟议研究的目标是诱导幸存的视网膜双极神经元对光的敏感性，这些神经元通常会接收来自光感受器的突触输入，作为在光感受器变性后恢复有用视力的策略。该方法是使用基因工程诱导双极神经元表达两种不同的光激活离子通道，通道视紫红质-2和halorhodopsin，这将分别模拟ON和OFF双极细胞的自然光反应。为了驱动双极神经元的表达，该项目将利用转基因动物，这些转基因动物在基因调控元件的控制下整合编码channelrhodopsin-2或halorhodopsin的DNA，这些基因调控元件将在双极神经元的两种亚型中选择性地表达。这些结果将建立使用这些遗传编码的光传感器蛋白作为患病视网膜中缺失的光感受器的功能替代品的可行性。 公共卫生相关性：视网膜感光细胞退化是失明的主要原因，目前尚无治疗方法。这项拟议的研究探索了一种新的方法来恢复视力，尽管感光细胞的损失。该策略使用分子工程使视网膜上剩余的神经元对光敏感，从而取代缺失的光感受器的功能。

DESCRIPTION (provided by applicant): The photoreceptor cells of the retina carry out the essential task of translating light into electrical signals that can be passed on and analyzed by the rest of the visual system. Diseases that cause the photoreceptor cells to degenerate lead to irreversible blindness, because the remaining neurons of the retina are not sensitive to light and therefore cannot substitute for the loss of the photoreceptor cells. The goal of the proposed research is to induce sensitivity to light in the surviving retinal bipolar neurons, which would normally receive synaptic inputs from photoreceptors, as a strategy to restore useful vision after photoreceptor degeneration. The approach is to use genetic engineering to induce bipolar neurons to express two different light-activated ion channels, channelrhodopsin-2 and halorhodopsin, that will mimic the naturally occurring light response of ON and OFF bipolar cells, respectively. To drive expression in bipolar neurons, the project will make use of transgenic animals that incorporate DNA encoding channelrhodopsin-2 or halorhodopsin under the control of gene regulatory elements that will confer expression selectively in each of the two subtypes of bipolar neurons. The results will establish the feasibility of using these genetically encoded photosensor proteins as a functional replacement for missing photoreceptors in the diseased retina. PUBLIC HEALTH RELEVANCE: Degeneration of the photoreceptor cells in the retina is a leading cause of blindness, and at present, there is no treatment. The proposed research explores a new approach for restoration of vision despite the loss of photoreceptor cells. The strategy uses molecular engineering to make the remaining neurons of the retina sensitive to light, thereby replacing the function of the missing photoreceptors.