Neuroprotection by Modulating ER Stress in Glaucoma

项目总结 青光眼是导致不可逆转失明的最常见原因，将影响1亿多人 到2040年，40岁到80岁之间。由于视神经变性(ON)而导致严重的视力丧失 视网膜神经节细胞(RGC)。临床上对神经保护剂的需求还远远没有得到满足。我们以前的 对创伤和青光眼的研究表明，急性和慢性损伤均可诱发 视网膜节细胞的内质网应激。如果我们能够保护受伤的RGC胞体和轴突 通过操纵未折叠的两个关键下游分子来阻断内质网应激的有害影响 相反方式的蛋白质反应(UPR)：a)CCAAT/增强子结合蛋白同源蛋白的缺失 (CHOP)和/或b)激活X-box结合蛋白1(XBP-1)。因此轴突损伤诱导的内质网应激可能是一种 神经元损伤的共同机制和靶向神经元内质网应激可能具有相当大的治疗作用 与轴索病变相关的疾病的神经保护潜力。作为第一步，我们建议确定 用细胞高通量筛选化学文库筛选新型内质网应激调节剂 检测；然后验证这些药物是否促进RGC和对生存和保护视觉功能的影响 在小鼠青光眼模型中。最近，关于轴突沃勒变性的令人兴奋的最新研究表明 参与轴突NAD代谢的几个关键分子在轴突变性中起关键作用。Sarm1 例如，(不育Alpha和TIR基序1)受轴突NAD合成酶的负调控 烟酰胺单核苷酸腺基转移酶2(NMNA2)诱导轴突变性；缺失 Sarm1或轴突NMNAs的激活导致轴突保护。因此，我们将检验这一假设 同时调节神经元内质网应激和NAD代谢将协同防止两者 青光眼患者RGC胞体和轴突的变性与视力保护。这项研究可能会产生新的 为患者提供更有效的神经保护的综合治疗策略。最后，我们会 开发用于RGC形态和功能研究的新的活体成像工具并获得急需的 对RGC内质网应激启动机制的认识。我们预计通过这些研究的结果将 为内质网应激调控的临床应用提供必要信息，并建立可翻译的 技术和生物标志物将极大地促进青光眼患者的临床管理。

PROJECT SUMMARY Glaucoma is the most common cause of irreversible blindness and will affect more than 100 million people between 40 to 80 years old by 2040. It causes severe visual loss due to degeneration of optic nerve (ON) and retinal ganglion cells (RGCs). There is a significant unmet clinical need for neuroprotectants. Our previous studies of ON traumatic injury and glaucoma demonstrated that both acute and chronic ON injury induce endoplasmic reticulum (ER) stress in RGCs. We were able to protect the injured RGC soma and axons if we blocked the detrimental effects of ER stress by manipulating two key downstream molecules of the unfolded protein response (UPR) in opposite ways: a) deletion of CCAAT/enhancer binding protein homologous protein (CHOP), and/or b) activation of X-box binding protein 1 (XBP-1). Thus axon injury-induced ER stress may be a common mechanism of neuronal damage and targeting neuronal ER stress may have considerable therapeutic neuroprotective potential in diseases associated with axonopathy. As the first step, we propose to identify novel ER stress modulators by screening chemical libraries with cell-based high throughput screen (HTS) assays; and then to validate whether these agents promote RGC and ON survival and preserve visual function in mouse glaucoma models. Recently, exciting recent studies of axonal Wallerian degeneration have shown that several key molecules involved in axonal NAD+ metabolism are critical for axonal degeneration. SARM1 (Sterile Alpha and TIR Motif 1), for example, is negatively regulated by axonal NAD+ synthetic enzyme nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) to induce axon degeneration; deletion of SARM1 or activation of axonal NMNATs results in axon protection. Thus, we will test the hypothesis that modulating both intrinsic neuronal ER stress and NAD+ metabolism will synergistically prevent both RGC soma and axon (ON) degeneration and preserve vision in glaucoma. This study may generate novel combinatory therapeutic strategies that lead to more efficient neuroprotection in patients. And finally, we will develop novel in vivo imaging tools for RGC morphology and function studies and acquire much needed insights into the mechanism of RGC ER stress initiation. We expect the results through these studies will provide essential information for clinical application of ER stress modulation, and establish translatable techniques and biomarkers that will greatly facilitate clinical management of glaucoma patients.