The role of optic nerve lamina region stem cells in age-related optic nerve disease

最常见的与年龄相关的视神经（ON）相关的视力丧失原因是非动脉炎性的 前部缺血性视神经病变（NAION）和原发性开角型青光眼（POAG）。视神经头 (ONH)缺陷有助于NAION和POAG易感性，但对此负责的机制是 不完全了解，导致缺乏有效的治疗方法。我的实验室最近发现 ONH内的神经板层区（ONLR）包含CNS神经干细胞/神经祖细胞 (NSC/NPC）生态位，其在老化期间被耗尽。CNS-NPC活性的增加已被证明可以改善 老年小鼠中的基线CNS活性，并且NPC耗竭阻碍损伤后CNS的恢复。 NPC分泌细胞外囊泡（“外来体”），其介导CNS-1的许多积极作用。 的npc我们发现给予人ONLR-NPC分泌的外泌体增强RGC离体存活， 刺激RGC-神经炎发生。在小鼠转基因模型中消耗ONLR-NPC增加了 RGC应激，使用RGC应激标记物组。我假设ONLR-NPC支持RGC的生存， 它们部分地通过囊泡分泌来实现这一点。我预测他们的损失会增加RGC的压力和对死亡的敏感性 在轴突缺血应激后，用ONLR-NPC-细胞外囊泡补充RGC将增强 轴突应激后RGC存活。我们将用两种啮齿动物和两个特定的目标来证明这一点。 具体目标1：证明小鼠ONLR-NPC缺失导致RGC应激和增加 ON疾病中的RGC死亡。我们将结合小鼠转基因模型， 消耗、NAION rNAION模型的啮齿动物模型和体视学（统计学上稳健的细胞定量）。 我们将利用分子和细胞生物学技术来鉴定RGC细胞应激和凋亡。我们将 然后：A）通过应激标志物分析确定急性ONLR-NPC消耗是否导致RGC应激， B）在rNAION诱导的RGC缺血性轴突应激后，这种消耗是否增强RGC死亡。我预测 增加的RGC应激，通过增加的RGC-pJun表达和增加的RGC损失证明。 具体目标2。证实大鼠ONLR-NPC“外泌体”在培养过程中和体内保护RGC。 缺血性ON应激。我们将分离大鼠ONLR-NPC分泌囊泡，并证实它们增强ONLR-NPC分泌囊泡的能力。 A）向培养的大鼠施用大鼠ONLR-NPC囊泡及其解离的组分 RGC，我们将量化它们增强RGC存活和神经炎发生的能力。我预测RGC的改进 存活和增加神经炎发生。B）使用rNAION模型，我们将玻璃体内注射大鼠ONLR-NPC 衍生的外泌体及其组分，并确定这些囊泡是否改善RGC存活， 减少压力相关的标记物，如CRF和pJun。我预测压力水平会降低， RGC生存。我们的创新方法会找出有助研资局抗压的因素， 产生新的、改进的治疗视神经疾病的方法。

The most common age-associated optic nerve (ON)-related causes of vision loss are non-arteritic anterior ischemic optic neuropathy (NAION) and primary open-angle glaucoma (POAG). Optic nerve head (ONH) defects contribute to NAION and POAG susceptibility, but the mechanisms responsible for this are incompletely understood, contributing to a lack of effective treatments. My lab recently discovered that the optic nerve-laminar region (ONLR) within the ONH, contains a CNS neural stem cell/neural progenitor cell (NSC/NPC) niche which is depleted during aging. Increased CNS-NPC activity has been shown to improve baseline CNS activity in aged mice, and NPC depletion impedes CNS recovery following injury. NPCs secrete extracellular vesicles (‘exosomes’) that mediate many of the positive effects of CNS- NPCs. We find that administering human ONLR-NPC-secreted exosomes enhance RGC survival ex vivo and stimulates RGC-neuritigenesis. Depleting ONLR-NPCs in a mouse transgenic model increases markers of RGC stress, using an RGC stress-marker panel. I hypothesize that ONLR-NPCs support RGC survival, and they do this in part by vesicle secretion. I predict their loss increases RGC stress and susceptibility to death after axonal ischemic stress, and supplementing RGCs with ONLR-NPC-extracellular vesicles will enhance RGC survival after axonal stress. We will prove this with two rodent species and two specific aims. Specific aim 1: Demonstrate that mouse ONLR-NPC loss results in RGC stress and increases RGC death in ON disease. We will couple a mouse transgenic model enabling selective ONLR-NPC depletion, the rodent model of NAION rNAION model, and stereology (statistically robust cell quantification). We will utilize molecular and cell biological techniques for identifying RGC cell stress and apoptosis. We will then: A) Determine whether acute ONLR-NPC depletion results in RGC stress, via stress marker analysis and B) Whether this depletion enhances RGC death after rNAION-induced RGC ischemic axonal stress. I predict increased RGC stress, demonstrable by increased RGC-pJun expression and increased RGC loss. Specific aim 2. Confirm that rat ONLR-NPC ‘exosomes’ protect RGCs in culture and in vivo during ischemic ON stress. We will isolate rat ONLR-NPC secreted vesicles and confirm their ability to enhance RGC survival, by: A) Administering rat ONLR-NPC vesicles and their dissociated components to cultured rat RGCs, we will quantify their ability to enhance RGC survival and neuritigenesis. I predict improved RGC survival and increased neuritigenesis. B) Using the rNAION model, we will intravitreally inject rat ONLR-NPC derived exosomes and their components and determine whether these vesicles improve RGC survival and reduce stress-related markers such as CRF and pJun. I predict reduced stress levels and improved long-term RGC survival. Our innovative approach will identify the factors that contribute to RGC stress resistance and generate new, improved approaches to treatment of optic nerve diseases.