Exosome RNA-Therapeutics to Promote CNS Myelination

描述（由申请人提供）：多发性硬化症（MS）是年轻人最常见的致残神经系统疾病。这是一种无法治愈的自身免疫性疾病，涉及少突胶质细胞丢失、脱髓鞘和受损大脑无法再髓鞘化。髓鞘再生随着年龄的增长和MS的进展而下降，其中少突胶质前体细胞（OPCs）被积极地阻止分化为髓鞘细胞。目前的治疗方法仅针对通过免疫抑制降低免疫能力来减少脱髓鞘。重要的是，目前还没有治疗方法可以防止髓鞘再生的不可避免的衰退。该项目旨在消除这一空白。OPC向髓鞘细胞的分化受某些microrna （mirna）的调节，这些microrna在MS病变中减少。值得注意的是，年轻大鼠的血液可以促进年老大脑的髓鞘再生。这项工作的基本原理来自于初步数据显示，血液来源的外泌体（细胞释放的小泡）含有触发髓鞘再生的mirna。来自年轻和环境富集（EE）大鼠血清的非免疫原性外泌体mirna增强了髓鞘再生。我们研究的长期目标是在理解情感表达如何保护大脑的基础上开发神经疗法。本应用程序的总体目标是开发含有mirna的外泌体作为脑髓鞘再生的治疗药物。该研究的核心假设是，这些外泌体将增强大脑的髓鞘再生，并可用于多发性硬化症的治疗。该项目有四个目标：目标1：建立干扰素- γ (IFN-γ)刺激的树突状细胞（dc）作为外泌体的有效来源，模拟ees外泌体，在片培养中增强髓鞘再生，而不会损伤或产生免疫反应。目的2：建立一种有效的方法，用制备的靶向miRNA物种装载DC外泌体，并与ee -外泌体和IFN-刺激的DC外泌体相比，在切片培养中建立它们在不损伤或免疫反应的情况下增强髓鞘再生的能力。目的3：在MS脱髓鞘大鼠模型中，建立静脉（然后鼻）给药（Aims 1-2）外泌体促进髓鞘再生的最佳效果，而不会损伤或产生免疫反应。目的4：确定静脉（然后鼻）给药（目的1-2）外泌体促进MS小鼠模型[实验性自身免疫性脑脊髓炎（EAE）]的再髓鞘形成的最佳效果，而不会损伤或增强免疫反应。结果测量将是：1)OPC，分化少突胶质细胞，致密髓磷脂水平，靶向mirna和靶标水平；2)毒性，通过细胞死亡、肝肾功能测定和肿瘤发生测定；3)通过血清和脑标记物检测免疫激活；4)疾病严重程度的临床指标。这项工作是创新的，因为它使用自然发生的信号分子和载体来传递e样髓鞘增强。这项研究具有重要意义，因为它将建立基于ee的含有mirna的外泌体作为一种新的治疗方法在不损害免疫的情况下对MS损伤的大脑进行髓鞘再化的临床前可行性和实用性。

DESCRIPTION (provided by applicant): Multiple sclerosis (MS) is the most common disabling neurological disease of young adulthood. It is an incurable autoimmune disorder involving oligodendrocyte loss, demyelination, and an inability to remyelinate damaged brain. Remyelination declines with age and MS progression, where oligodendrocyte precursor cells (OPCs) are actively prevented from differentiating into myelinating cells. Current therapies are only directed at reducing demyelination via immune suppression which reduces immune competence. Importantly, no therapies exist to prevent the inevitable decline in remyelination. This project is designed to remove this void. OPC differentiation into myelinating cells is regulated by certain microRNAs (miRNAs) that are reduced in MS lesions. Notably, blood from young rats enhances remyelination of aged brain. The rationale for this work comes from pilot data showing that blood-derived exosomes, small vesicles released from cells, contain miRNAs that trigger remyelination. Non-immunogenic exosomal miRNAs from the serum of young and environmentally enriched (EE) rats enhanced remyelination. The long-term goal of our research is to develop neurotherapeutics based on understanding how EE protects brain. The overall goal of this application is to develop exosomes containing miRNAs as a therapeutic for brain remyelination. The central hypothesis is that these exosomes will enhance remyelination of brain and can be crafted into a therapy for MS. The project has four Aims: AIM 1: Establish interferon-gamma (IFN-γ) -stimulated dendritic cells (DCs) as an effective source of exosomes that mimic EE-exosomes to enhance remyelination without injury or immune reaction in slice cultures. AIM 2: Establish an efficient means of loading DC exosomes with fabricated targeted miRNA species and establish their ability to enhance remyelination without injury or immune reaction in slice cultures compared to EE-exosomes and IFN-γ-stimulated DC exosomes. AIM 3: Establish the optimal efficacy of intravenously (then nasally) delivered (Aims 1-2) exosomes to promote remyelination without injury or immune reaction in a rat lysolecithin model of MS demyelination. AIM 4: Establish the optimal efficacy of intravenously (then nasally) administered (Aims 1-2) exosomes to promote remyelination in a mouse model of MS [experimental autoimmune encephalomyelitis (EAE)] without injury or enhanced immune reaction. Outcome measures will be: 1) OPC, differentiated oligodendrocyte, and compact myelin levels, targeted miRNAs & target levels; 2) toxicity, measured by cell death, liver and renal function assays, plus oncogenesis; 3) immune activation assayed by serum and brain markers; and 4) clinical measures of disease severity. The work is innovative because it uses naturally occurring signaling molecules and vehicles for delivery of EE-like enhancement of myelination. The proposed research is significant because it will establish the preclinical feasibility and utility of EE-based miRNA-containing exosomes as a novel therapeutic to remyelinate MS- damaged brain without immune compromise.