Expression of genetically encoded photosensors in retinal bipolar neurons

描述(申请人提供)：视网膜的光感受器细胞执行将光转换成电信号的基本任务，这些电信号可以传递给视觉系统的其余部分并进行分析。导致感光细胞退化的疾病会导致不可逆转的失明，因为视网膜剩余的神经元对光不敏感，因此不能取代感光细胞的丧失。这项拟议的研究的目标是在存活的视网膜双极神经元中诱导对光的敏感性，作为一种在光感受器退化后恢复有用视力的策略。该方法是利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-视紫红质-2和卤视紫红质，分别模拟双极细胞自然产生的光反应。为了推动双极神经元的表达，该项目将利用转基因动物，在基因调控元件的控制下整合编码通道视紫红质-2或卤视紫质的DNA，这些基因调控元件将在两种亚型的双相神经元中选择性地表达。这一结果将确立使用这些基因编码的光感受器蛋白作为疾病视网膜中缺失的光感受器的功能替代的可行性。 公共卫生相关性：视网膜中感光细胞的退化是导致失明的主要原因，目前还没有治疗方法。这项拟议的研究探索了一种新的方法，可以在感光细胞丢失的情况下恢复视力。该策略使用分子工程来使视网膜中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.