Retinal Ganglion Cell Dendrite and Synapse Regeneration in Glaucoma: the Role of Insulin Signaling.

青光眼是世界范围内导致不可逆转失明的主要原因。青光眼的视力丧失是由 视网膜神经节细胞(RGC)选择性死亡。伴随突触解体的RGC树突快速回缩， 被鉴定为青光眼损伤后的早期病理改变，导致神经元功能障碍和死亡。 许多研究都集中在轴突再生上，但对视网膜节细胞再生的能力知之甚少。 树枝状结构。我们最近证实，在显著的树突状树枝收缩后给予胰岛素 在视神经切断后和小鼠青光眼模型中促进RGC树突再生。 然而，有几个关键问题仍然没有答案：1)胰岛素是否会再生突触并恢复 青光眼损害后的神经元功能？2)胰岛素受损是树突状病变的触发信号吗？ 在青光眼中？3)胰岛素介导的树突再生的机制是什么？4)什么是 胰岛素对RGC修复的翻译潜力？在本申请中，我们提出了将填补这一问题的研究 知识鸿沟和验证胰岛素信号对树突再生至关重要的总体假说 青光眼的功能恢复。我们将使用已建立的小鼠和非人类青光眼模型 灵长类以及功能得失范例和创新方法在三个独立的，至今 相辅相成，目标明确。在目标1中，我们将检验胰岛素再生树突和 突触导致神经元功能的持续恢复。这些研究还将确定 不同的RGC亚型有能力安装强大的再生反应并重建适当的 突触连接。在目标2中概述的实验将检验以下假设：i)损伤胰岛素信号 雷帕霉素(MTOR)撞击哺乳动物靶点介导早期树突状细胞病变和突触 消除，以及ii)胰岛素介导的树突再生涉及蛋白质的下游真正效应分子 翻译和细胞骨架调节。在目标3中，我们将检验胰岛素治疗的假设，包括 基因治疗，将有效促进长期RGC树突再生，恢复非视神经病变患者的视功能 人类灵长类青光眼。我们将利用我们的能力使用纵向活体成像和 用于监测疾病发病、进展和康复的电生理技术。这样做的结果是 应用将对我们理解促进研资局的新机制和目标产生重大影响 树突和突触的再生以及视觉功能的恢复。重要的是，这个项目将 生成严谨且令人信服的临床前数据，作为知识转化的跳板 胰岛素作为青光眼治疗策略的临床发展。

Glaucoma is the leading cause of irreversible blindness worldwide. Loss of vision in glaucoma is caused by the selective death of retinal ganglion cells (RGCs). Rapid retraction of RGC dendrites with synapse disintegration, identified as an early pathological change after glaucomatous injury, leads to neuronal dysfunction and death. Many studies have focused on axonal regeneration, yet little is known about the ability of RGCs to regenerate dendrites. We recently demonstrated that insulin administered after substantial dendritic arbor shrinkage promoted robust RGC dendrite regeneration after optic nerve axotomy and in a mouse glaucoma model. However, several key questions remain unanswered: 1) does insulin regenerate synapses and restore neuronal function after glaucomatous damage? 2) Is impaired insulin signaling a trigger for dendritic pathology in glaucoma? 3) What are the mechanisms driving insulin-mediated dendrite regeneration? 4) What is the translational potential of insulin for RGC repair? In this application, we propose studies that will fill this knowledge gap and test the overarching hypothesis that insulin signaling is crucial for dendrite regeneration and functional restoration in glaucoma. We will use established models of glaucoma in mice and non-human primates as well as gain- and loss-of-function paradigms and innovative approaches in three independent, yet complementary, specific aims. In Aim 1, we will test the hypothesis that insulin regenerates dendrites and synapses leading to sustained restoration of neuronal function. These studies will also determine whether different RGC subtypes have the ability to mount a strong regenerative response and reestablish appropriate synaptic connectivity. Experiments outlined in Aim 2, will test the hypotheses that: i) impaired insulin signaling impinging on the mammalian target of rapamycin (mTOR) mediates early dendritic pathology and synapse elimination, and ii) insulin-mediated dendrite regeneration involves downstream bona fide effectors of protein translation and cytoskeletal regulation. In Aim 3, we will test the hypothesis that insulin treatment, including gene therapy, will effectively promote long-term RGC dendrite regeneration and restore visual function in non- human primate glaucoma. We will capitalize on our ability to use longitudinal in vivo imaging and electrophysiological techniques to monitor disease onset, progression, and recovery. The outcome of this application will have a major impact on our understanding of novel mechanisms and targets that promote RGC dendritic and synaptic regeneration as well as restoration of visual function. Importantly, this project will generate rigorous and compelling pre-clinical data that will serve as a knowledge-translation springboard towards the clinical development of insulin as a therapeutic strategy for glaucoma.