Optogenetic Vision Restoration

超过100，000名各年龄段的美国人患有遗传性视网膜疾病（IRD），导致视力逐渐丧失。在大多数IRD中，疾病始于杆，导致从周边到中心的视力丧失，使患者无法导航周围环境。电子视网膜假体恢复受IRD影响的患者的有用视力，光遗传学是一种替代治疗方法。微生物视蛋白用于恢复视网膜光敏感性的主要限制是激活通道视紫红质所需的高光强度。解决这个问题的一个方法是使用具有更高光敏感度但足够快的动力学的视蛋白来实现有用的运动视觉。 我们提出了一种新的方法来恢复视力的病人使用病毒表达光敏 蛋白质在特定的，二级视网膜神经元，使他们的光敏感。我们的方法使用一个共同的 一种神经元受体，经修饰后对剩余的光不敏感的视网膜神经元增加了光感受功能 感光细胞退化后存活的神经元。受体使用视网膜， 或通过玻璃体内注射递送的合成化学光开关。通过这种方式， 感受器所在的位置对光线的反应是神经放电的变化。这补偿了他们的损失 光感受器的输入，恢复对视网膜的光反应，并将信息发送到视网膜。 大脑恢复视力。在大多数情况下，这种方法与引起突变的突变无关。 光感受器变性这种方法可能会导致导致RPE细胞死亡的疾病，如 无脉络膜 到目前为止，这种方法的版本，由联合PI Isacoff和Flannery以及其他人开发， 领域，已经采用了对光相当不敏感或反应非常缓慢的受体，因此不能 支持正常视力。我们现在提出了一种新的策略，该策略利用了 GPCR信号，以提高灵敏度（1000倍）和速度。GPCR信号级联是内在的 视杆细胞和视锥细胞，以及双极细胞、神经节细胞和视网膜中的其他细胞。我们也追求一个新的 发现，从我们的初步实验中出现，这使得一种组合方法， 一次使用一个以上的光学传感器分子，以重建自然生物的自然多样性。 视网膜中的信号传递，而这些信号在早期是缺失的。最后，我们采用复杂的行为分析， 不仅测试恢复的能力，以区分光从黑暗或闪烁从稳定的光，但以确定 如果动物能够看到图像。这一计划的成功将标志着在创建 一种基于基因疗法的视网膜修复术

Over 100,000 Americans of all ages suffer from inherited retinal diseases (IRD), which cause a progressive loss of vision. In most IRDs, disease begins in the rods, causing vision loss from the periphery to the center, leaving patients unable to navigate their surroundings. Electronic retinal prosthesis restore useful vision in patients affected by IRDs, and optogenetics is an alternative therapeutic. A major limitation of microbial opsins for restoration of retinal light sensitivity is the high light intensity required for activating channelrhodopsins. A solution to this caveat is the use of opsins with higher light sensitivity but sufficiently fast kinetics for useful motion vision. We propose a novel approach to restore vision to patients using a virus to express a light sensitive protein in specific, second-order retina neurons to make them light sensitive. Our approach uses a common neuronal receptor, modified to add a light receptive function to the remaining light-insensitive retinal neurons that survive after photoreceptor degeneration. The receptor uses either retinal, which is available in the eye, or a synthetic chemical photoswitch delivered by intravitreal injection. In this way, the cells in which the receptor is located respond to light with a change in neural firing. This compensates for their loss of input from photoreceptors, restoring light responsiveness to the retina and sending information to the brain to restore vision. In most cases, this approach is independent of the mutation that caused the photoreceptor degeneration. Exceptions to this approach may be diseases that cause RPE cell death, such as choroideremia. To date, versions of this approach, developed by Co-PIs Isacoff and Flannery, and others in the field, have employed receptors that are rather insensitive to light or very slow in response and so could not support normal vision. We now propose a new strategy that uses the natural amplification properties of GPCR signaling to increase sensitivity (by 1000 times) and speed. GPCR signaling cascades are intrinsic to rods and cones, as well as bipolar, ganglion cells and other cells in the retina. We also pursue a new discovery, emerging from our preliminary experiments, which enables a combinatorial approach that uses more than one optical sensor molecule at a time in order to recreate the natural diversity of natural signaling in the retina that had earlier been missing. Finally, we employ sophisticated behavioral analysis to test not only the restoration of the ability to tell light from dark or flashing from steady light, but to determine if the animal is able to see images. Success of this program would represent a major step in the creation of a retinal prosthetic based on gene therapy.