Neuronal antigen surveillance and autoimmunity in CNS demyelinating disease

有一个关键的未满足的需要，以确定致病机制，推动疾病进展的患者 多发性硬化症（MS）MS中轴突损伤和功能障碍的累积不足以 受当前治疗的影响。这项工作的长期目标是发现新的战略，以防止或 尽管有证据表明CD 8 + T细胞与轴突损伤相关， MS的进展，这些细胞的功能作用以及募集细胞所需的相关机制。 这些细胞与脱髓鞘的大脑的联系尚不清楚。神经元特异性CD 8 + T细胞的抗原靶标是 也是未知的。本研究的总体目标是测试神经元抗原特异性 CD 8 + T细胞在脱髓鞘轴突损伤中的作用，并确定MS患者是否有此类细胞。 基本原理是轴突损伤是MS进展的主要底物，轴突MHC I类表达 是上调炎症和脱髓鞘，细胞毒性CD 8 + T细胞针对神经元特异性 抗原损伤脱髓鞘轴突。该建议的中心假设是，神经元抗原特异性 CD 8 + T细胞损伤脱髓鞘轴突。在强有力的初步证据的指导下， 使用AAV介导的神经元转导来驱动新抗原卵清蛋白（OVA）在神经元内的表达， 由铜腙毒性或针对髓鞘少突胶质细胞的免疫诱导的CNS脱髓鞘的背景 糖蛋白衍生肽（MOG-EAE）在具有针对OVA的转基因CD 8 + T细胞的宿主中的表达。 衍生肽SIINFEKL（OT-I）。该研究还将使用自体T细胞和成纤维细胞衍生的iPSC- 在微流控室中生长的衍生神经元，以确定MS患者CD 8 + T细胞是否损伤其自身 轴突本研究的目的有三：1）明确CD 8 + T细胞介导的轴突损伤机制 2）鉴定轴突损伤所需的MHC I类表达的细胞位点， 确定脱髓鞘如何驱动神经元抗原特异性CD 8 + T细胞的CNS浸润; 3）确定 MS患者是否具有神经元抗原特异性CD 8 + T细胞。这种方法在概念上是创新的 由于脱髓鞘和炎症诱导轴突呈递自身肽的提议， MHC I类。该方法在技术上是创新的，其基于使用新型AAV载体来驱动 脱髓鞘CNS内神经元中的新抗原，脑驻留抗原呈递的选择性缺失 细胞（APC）与外周APC，使用多个宿主操作与可追踪的 效应细胞在时间和空间上分析抗神经元T细胞运输，以及使用患者来源的 神经元和自体CD 8 + T细胞。这项工作将对该领域产生重大而有力的影响， 揭示了针对神经元特异性抗原的CD 8 + T细胞损伤脱髓鞘轴突的能力 并通过在MS患者中鉴定这种T细胞。

There is a critical unmet need to identify the pathogenic mechanisms that drive disease progression in patients with multiple sclerosis (MS). Accumulation of axon injury and functional disability in MS are not adequately impacted by current therapies. The long-term goal of this work is to discover new strategies to prevent or reverse disease progression in MS. Despite evidence that CD8+ T cells are associated with axon injury and progression in MS, the functional role for these cells and the relevant mechanisms required for recruitment of these cells to the demyelinated brain are unknown. The antigenic targets of neuron-specific CD8+ T cells are also unknown. The overall objectives of this study are to test the mechanistic role of neuron antigen-specific CD8+ T cells in the injury of demyelinated axons and to determine whether patients with MS have such cells. The rationale is that axon injury is the primary substrate of progression in MS, axonal MHC class I expression is upregulated by inflammation and demyelination, and cytotoxic CD8+ T cells directed against neuron-specific antigens injure demyelinated axons. The central hypothesis of this proposal is that neuron antigen-specific CD8+ T cells injure demyelinated axons. Guided by strong preliminary evidence, the hypothesis will be tested using AAV-mediated transduction of neurons to drive expression of the neoantigen ovalbumin (OVA) within the context of CNS demyelination induced by cuprizone toxicity or immunization against a myelin oligodendrocyte glycoprotein-derived peptide (MOG-EAE) in hosts that have transgenic CD8+ T cells directed against the OVA- derived peptide SIINFEKL (OT-I). The study will also use autologous T cells and fibroblast-derived iPSC- derived neurons grown in microfluidic chambers to determine whether MS patient CD8+ T cells injure their own axons. Three specific aims will be pursued: 1) determine the mechanisms of CD8+ T cell-mediated axon injury in the demyelinated CNS; 2) identify the cellular locus of MHC class I expression required for axon injury and determine how demyelination drives CNS infiltration of neuron antigen-specific CD8+ T cells; 3) determine whether MS patients have neuron-antigen specific CD8+ T cells. This approach is conceptually innovative because of the proposal that demyelination and inflammation induce axonal presentation of self-peptides on MHC class I. The approach is technically innovative based on the use of novel AAV vectors to drive neoantigens in neurons within the demyelinated CNS, selective deletion of brain-resident antigen presenting cells (APCs) vs peripheral APCs, use of multiple host manipulations coupled to adoptive transfer of traceable effector cells to temporally and spatially profile anti-neuronal T cell trafficking, and the use of patient-derived neurons and autologous CD8+ T cells. This work will make a significant, powerful impact on the field by revealing the capacity of CD8+ T cells directed against neuron-specific antigens to injure demyelinated axons and by identifying such T cells in patients with MS.