A new strategy for vision restoration based on melanopsin transduction mechanisms

基于黑视蛋白转导机制的视力恢复新策略

• 批准号: 10502717
• 负责人: Zheng Jiang
• 金额: $ 40万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10502717
• 关键词: Animals; Blindness; Brain; Cell Death; Cells; Cyclic Nucleotides; Data; Death Rate; Dominant-Negative Mutation; Effectiveness; FOS gene; Family; Future; G-Protein-Coupled Receptors; Image; Inflammatory Response; Ion Channel; Kinetics; Knowledge; Light; Measures; Mediating; Modality; Modification; Monitor; Mus; Names; PDE4A4; Pathway interactions; Pattern; Phase; Photophobia; Photoreceptors; Photosensitivity; Phototransduction; Proteins; Retina; Retinal Diseases; Retinal Ganglion Cells; Reverse Transcriptase Polymerase Chain Reaction; Signal Pathway; Signal Transduction; Signaling Molecule; Testing; Therapeutic; Vertebrate Photoreceptors; Viral; Vision; Visual; Water; Work; activity marker; base; behavior test; cyclic-nucleotide gated ion channels; density; gene therapy; immunocytochemistry; improved; innovation; knowledge base; light intensity; melanopsin; member; mouse model; multi-electrode arrays; mutant; novel; optogenetics; overexpression; patch clamp; photoactivation; photoreceptor degeneration; relating to nervous system; response; restoration; retinal neuron; sight restoration; temporal measurement; theories; treatment strategy; trend; vision aid

PROJECT SUMMARY A pressing challenge in the treatment of retinal diseases is to restore vision in the retina with irreversible photoreceptor degeneration. In theory, even in the absence of rods and cones, such diseased retina should still be able to sense light through intrinsically photosensitive retinal ganglion cells (ipRGCs) using a photopigment named melanopsin. However, the kinetics of melanopsin-mediated light response is slow, thus giving only very poor temporal resolution and therefore largely limiting its ability to provide image-forming information. For the same reason, a vision restoration approach previously proposed – which made use of virally expressed melanopsin to endow light sensitivity to conventional retinal ganglion cells (RGCs) – is also limited by the slow response kinetics of melanopsin. Our recent study has firmly established that melanopsin-mediated phototransduction is rate-limited by its downstream components and that it can be accelerated by virally expressed ion channels with faster kinetics. We propose to develop a novel vision restoration strategy by accelerating melanopsin signaling via manipulating downstream transduction components in photoreceptor degenerated mouse models. We have two major aims. In Aim 1, we shall focus on enhancing the light response of endogenous melanopsin in M4- and M5-subtypes of ipRGCs because they have been shown to project to image-forming brain centers, allowing them to contribute to the image-forming vision. We have discovered that M4-cells respond to melanopsin photoactivation by elevating intracellular levels of cyclic nucleotides (cNMP) and subsequent opening of cNMP-sensitive HCN channels. Our new preliminary data suggest that M5 cells also use the HCN pathway. We have further shown that the response of the HCN-dependent signaling pathway can be sped up by introducing a member of the cyclic nucleotide-gated channel family, CNGA2, resulting in faster response kinetics and larger amplitudes, proving the concept of our strategy. In Aim 2, we shall restore light response in conventional retinal ganglion cells using virally expressed melanopsin together with faster signaling molecules. Our multielectrode array results show that simultaneously expressing melanopsin and CNGA2 in cRGCs provides higher light sensitivities and faster rising phases than expressing melanopsin alone. Using water-based vision-guided maze tests, we have further found that exogenous melanopsin and CNGA2 not only restore light sensitivity but also confer pattern vision in photoreceptor-degenerated animals. Together, these exciting preliminary observations raise the prospect of using CNG channels and/or modifications to other phototransduction components of melanopsin as a therapeutic modality to restore vision following photoreceptor degeneration. Innovation. All optogenetic approaches proposed thus far focus on finding a better light-sensing protein with higher expression, better light sensitivity, and faster response kinetics. We are the first to exploit downstream components and novel signaling molecules of melanopsin for vision restoration purposes. This represents a conceptual innovation and an out-of-the-box strategy for vision restoration.

项目概要 治疗视网膜疾病的一个紧迫挑战是通过不可逆的恢复视网膜视力 理论上，即使没有视杆细胞和视锥细胞，这种病变的视网膜仍然应该存在。 能够使用感光色素通过本质光敏视网膜神经节细胞 (ipRGC) 感知光 然而，黑视蛋白介导的光响应的动力学很慢，因此只能给出非常低的光响应。 时间分辨率差，因此很大程度上限制了其提供图像形成信息的能力。 同样的原因，之前提出的视力恢复方法——利用病毒式表达 黑视蛋白赋予传统视网膜神经节细胞 (RGC) 光敏感性 - 也受到缓慢的限制 我们最近的研究证实了黑视蛋白介导的反应动力学。 光转导受到其下游组件的速率限制，并且可以通过病毒加速 我们建议通过更快的动力学来开发一种新颖的视力恢复策略。 通过操纵感光器中的下游转导组件加速黑视蛋白信号传导 我们有两个主要目标，即目标 1，我们将重点关注增强光响应。 ipRGC 的 M4 和 M5 亚型中的内源性黑视蛋白，因为它们已被证明可以投射 我们发现，大脑中的图像形成中心有助于形成图像视觉。 M4 细胞通过提高细胞内环核苷酸 (cNMP) 水平来响应黑视蛋白光活化 随后打开 cNMP 敏感的 HCN 通道，我们的新初步数据表明 M5 细胞也使用。 我们进一步表明，HCN 依赖性信号通路的反应可以是 通过引入环核苷酸门控通道家族的成员 CNGA2 来加速，从而导致更快 响应动力学和更大的振幅，证明了我们策略的概念。在目标 2 中，我们将恢复光。 使用病毒表达的黑视蛋白和更快的信号传导在传统视网膜神经节细胞中做出反应 我们的多电极阵列结果表明，同时表达黑视蛋白和 CNGA2。 与单独表达黑视蛋白相比，cRGC 提供更高的光敏感性和更快的上升阶段。 通过水基视觉引导迷宫测试，我们进一步发现外源黑视蛋白和CNGA2不仅 恢复光敏感度，同时赋予光感受器退化的动物图案视觉。 令人兴奋的初步观察结果提出了使用 CNG 管道和/或对其他管道进行改造的前景 黑视蛋白的光转导成分作为光感受器后恢复视力的治疗方式 迄今为止提出的所有光遗传学方法都集中于寻找更好的光传感。 我们是第一个开发出具有更高表达、更好光敏感性和更快响应动力学的蛋白质。 用于视力恢复目的的黑视蛋白下游成分和新型信号分子。 代表了视力恢复的概念创新和开箱即用的策略。