Inflammation and Degeneration of Optic Nerve in EAE

视神经损伤导致的视力受损是患者最常见的症状之一。 患有多发性硬化症(MS)。多发性硬化相关的视神经损伤是由于自身反应性T细胞和 其他免疫细胞。炎症过程被认为有助于脱髓鞘，轴突变性， 少突胶质细胞和视网膜神经节细胞(RGC)丢失。了解视神经的病理生理学 EAE的神经变性具有潜在的治疗意义，可以开发恢复视觉功能的药物。 钙蛋白酶是一种依赖钙离子的蛋白酶，其活性和表达在骨质疏松症患者中显著增强。 用实验性变态反应性脑脊髓炎(EAE)建立多发性硬化的动物模型，对Lewis大鼠的抽动神经有免疫抑制作用。 在EAE的视神经损伤中发挥了钙蛋白酶的作用。因为炎症和机械反应的准确时间- 视神经中细胞和轴突的损伤机制尚不完全清楚，有可能预防炎症 以及导致轴突和细胞损伤的分子事件，可能会改善和恢复功能。我们假设- 钙蛋白酶介导的自身反应性T细胞活化和免疫细胞向中枢神经系统渗透的大小 会因炎症导致轴突和少突胶质细胞损伤而导致视觉功能丧失 在EAE视神经中继发性视网膜节细胞丢失，可能发生在临床症状之前 疾病。一个必然的假设是，在挑战之后的不同时间点抑制钙蛋白酶 会通过防止外周和视神经发炎来恢复视觉功能，阿米里奥- 视神经受损后的神经退行性变已经开始。数据表明，钙离子内流， EAE视神经中钙蛋白表达增加、轴突损伤、细胞死亡和视网膜损伤 发病前有几个参数会受到影响。钙蛋白酶抑制剂治疗减少免疫细胞 渗透、钙蛋白表达、细胞死亡和视网膜损伤，导致视觉反应改善 与未经治疗的EAE动物相比。干扰素在体外诱导神经胶质细胞钙激活酶激活 MBP特异性T细胞上清液可降解MBP。为了测试这些目标，设计了以下具体目标 假设：(1)决定炎症反应的时间、钙离子内流、钙依赖事件、细胞 EAE视神经中的死亡和轴突/髓鞘变性以及视网膜节细胞的状态 EAE动物在挑战后的视觉功能障碍；(2)调查Calain抑制剂是否治疗 将通过改变免疫臂(T细胞激活，免疫细胞渗入视神经)来恢复视觉功能 与车辆相比，急性EAE中的神经退行性臂(细胞死亡、轴突损伤) 治疗动物；和(3)检测钙蛋白酶抑制剂在保存和保护视网膜节细胞功能中的作用。 在体外，当受到促炎细胞因子或与激活的MBP的上清液孵育时- 特定的T细胞。了解视神经损伤的过程和时间将进一步发展 治疗多发性硬化视神经变性所致损害的最佳策略

Impaired vision due to optic nerve damage is one of the most common presenting symptoms of patients with multiple sclerosis (MS). MS-associated optic nerve damage is due to an influx of auto-reactive T cells and other immune cells. The inflammatory process is thought to contribute to demyelination, axonal degeneration, and loss of oligodendrocytes and retinal ganglion cells (RGCs). Understanding the pathophysiology of optic nerve degeneration in EAE has potential therapeutic implications to develop agents that restore visual function. Demonstration of increased activity and expression of calpain, a calcium (Ca2+)-dependent protease, in op- tic nerve using an animal model of MS, experimental allergic encephalomyelitis (EAE), in Lewis rats has im- plied a role for calpain in optic nerve damage in EAE. Since the precise timing of inflammation and mecha- nisms of cell and axon damage in optic nerve are not fully understood, the potential to prevent inflammation and molecular events that lead to axonal and cell damage, may improve and restore function. We hypothe- size that calpain-mediated activation of auto-reactive T cells and immune cell infiltration into the CNS will result in loss of visual function due to inflammation leading to axon and oligodendrocyte damage in EAE optic nerve with subsequent loss of RGCs which may occur prior to clinical symptoms of disease. A corollary hypothesis is that inhibiting calpain at different time-points following challenge will restore visual function by preventing inflammation in the periphery and in optic nerve, and amelio- rate neurodegeneration after damage to the optic nerve have begun. Data indicate that Ca2+ influx, calpain expression, axonal damage, cell death, and retinal damage are increased in EAE optic nerve with several parameters affected before disease onset. Treatment with calpain inhibitors reduced immune cell infiltration, calpain expression, cells death, and retinal damage, resulting in improved visual responses compared to untreated EAE animals. In vitro interferon (IFN¿) induced calpain activation in glial cells and MBP-specific T cell supernatant degraded MBP. The following specific aims have been designed to test these hypotheses: (1) determine the timing of inflammatory responses, Ca2+ influx, Ca2+-dependent events, cell death, and axonal/myelin degeneration in EAE optic nerve and examine the status of RGCs in correlation with visual dysfunction in EAE animals following challenge; (2) investigate whether treatment with calpain inhibitors will restore visual function by altering the immune arm (T cell activation, immune cell infiltration into optic nerve) and/or the neurodegenerative arm (cell death, axonal damage) in acute EAE, as compared to vehicle treated animals; and (3) examine the effects of calpain inhibitors in preserving and protecting function of RGCs in vitro when subjected to pro-inflammatory cytokines or incubated with supernatant from activated MBP- specific T cells. Understanding the process and timing of optic nerve damage will further the development of treatment of strategies to best restore the impairment caused by optic nerve degeneration in MS.