Targeting Cholesterol Homeostasis to maintain vision in MS-like optic neuritis

项目摘要/摘要： 急性视神经炎通常是自身免疫性疾病的首发症状。 多发性硬化症(MS)等脱髓鞘疾病。术后视力恢复良好是很常见的， 但相当多的多发性硬化症患者的预后很差，视力严重受损 以及随着疾病的发展而永久失明。多发性硬化症患病率的增加将导致 卫生保健系统面临巨大的社会和财政挑战，需要更多的研究来 提高这些疾病的治疗成功率。 富含胆固醇的髓鞘碎屑循环受损，新生合成减少 在脱髓鞘动物模型中，胆固醇已被确定为恢复的关键限制因素。我们 已经显示主要的胆固醇外流转运蛋白1，ABCA1和 实验性视黄醇生成系统中胆固醇稳态的改变 自身免疫性脑脊髓炎(EAE)-ON。然而，ABCA1基因变化的确切机制 影响胆固醇回收的表达仍然难以捉摸。我们假设这一损害发生在 胆固醇的合成和运输显著影响RGC的存活，突触可塑性和 通过ABCA1调节反馈重新髓鞘形成和恢复胆固醇稳态 改善视力障碍。 在特定的目标1中，我们将确定ABCA1表达对固醇的调节影响 体外合成和突触可塑性、胆固醇运输和髓鞘形成。眼睛和大脑 来自健康受试者和多发性硬化症患者的有机物将暴露于ABCA1抑制剂、肿瘤坏死因子α/干扰素γ或 脱髓鞘试剂溶血磷脂。挽救的ABCA1表达对甾醇合成的影响 胆固醇的摄取和运输、突触形成和髓鞘形成将使用单细胞进行检测。 RNA测序、免疫组织化学和胆固醇外流分析。在具体目标2中，我们将 确定ABCA1表达变化在分子、功能和结构上的影响 EAE-ON和MSEAE-ON在小鼠体内的视黄醇生成途径及ABCA1的影响 将使用视动反应、光学相干断层扫描、 图形视网膜电图和视觉诱发电位，随后是死后分子和 组织病理学分析。此外，多发性硬化症供者的胆固醇平衡紊乱也将被确定。 眼部组织。 我们提出的实验将大大提高对胆固醇作用的理解。 类MS-ON中的动态平衡，为未来的翻译和治疗提供了宝贵的资源 学习。

Project Summary/Abstract: Acute optic neuritis (ON) is often the initial presenting manifestation of autoimmune demyelinating disorders such as Multiple Sclerosis (MS). Good recovery of vision after ON is common, but a considerable number of MS patients experience poor outcomes with severe visual impairment and permanent blindness as disease progresses. The increasing prevalence of MS will cause an immense social and financial challenge for health care systems and more studies are needed to improve treatment success in these diseases. Impaired recycling of cholesterol-rich myelin debris and decreased de novo synthesis of cholesterol have been identified as key limiting factors of recovery in demyelinating animal models. We have demonstrated decreased expression of the main cholesterol efflux transporter1, Abca1, and altered cholesterol homeostasis in the retinogeniculate system of animals with Experimental Autoimmune Encephalomyelitis (EAE)-ON. However, the exact mechanism by which changes in Abca1 expression affect cholesterol recycling remain elusive. We hypothesize that this impairment in cholesterol synthesis and transport significantly affects RGC survival, integrity of synaptic plasticity and remyelination and that restoration of cholesterol homeostasis via Abca1 regulatory feedback ameliorates visual impairment. In specific aim 1, we will determine the regulatory influence of ABCA1 expression on sterol synthesis and synaptic plasticity, cholesterol transport, and myelination in vitro. Eye and brain organoids from healthy subjects and MS patients will be exposed to Abca1 inhibitors, TNFα/IFNγ, or the demyelinating agent Lysolecithin. Effects of rescued Abca1 expression on sterol synthesis, cholesterol uptake and transport, synaptogenesis and myelination will be examined using single-cell RNA-sequencing, immunohistochemistry, and cholesterol efflux assays. In specific aim 2, we will determine the molecular, functional, and structural impact of Abca1 expression changes in the retinogeniculate pathway of EAE-ON and MS. EAE-ON will be induced in mice and effects of Abca1 expression changes will be determined using optokinetic response, optical coherence tomography, pattern electroretinography, and visual evoked potentials, followed by postmortem molecular and histopathologic analysis. Also, disruption in cholesterol homeostasis will be determined in MS donor eye tissue. Our proposed experiments will significantly advance the understanding of the role of cholesterol homeostasis in MS-like ON and provide an invaluable resource for future translational and therapeutic studies.