Oligodendrocyte extracellular vesicles: a novel therapy for CNS autoimmunity

摘要：少突胶质细胞外囊泡：一种治疗CNS自身免疫的新方法。 目前多发性硬化症（MS）的治疗以抗原（Ag）非特异性方式靶向免疫系统， 由于系统性免疫抑制可能会有严重的副作用。MS研究的一个长期目标是 设计一种Ag特异性治疗方法，只抑制有害的免疫反应，而不影响其他免疫反应。 免疫系统完好无损抗原特异性治疗的前提是确定靶抗原。MS 发病机制被广泛认为是由针对髓磷脂Ag的自身免疫驱动的。然而，相关Ag（s） 在MS中仍然是推测性的，这些Ag在患者之间存在差异的可能性，并且随着时间的推移， 病人已经证明了许多方法用于Ag特异性抑制自身免疫性神经炎症 在实验性自身免疫性脑脊髓炎（EAE），MS的动物模型。 通过在非炎症环境中递送相同的自身抗原来建立对自身抗原的外周耐受性（例如，在 PBS），例如静脉内（i. v.），口腔或鼻腔。然而，这些实验的翻译 MS治疗策略的进展受到MS患者中相关Ag的不确定性的阻碍。在 为了解决这个问题，我们推断，如果我们使用少突胶质细胞（Ol）衍生的 细胞外囊泡（Ol-EV），其天然含有大部分或全部的髓鞘Ag，将没有必要 确定每个患者的相关髓鞘抗原。此外，我们还假设，静脉注射Ol-EV将 抑制EAE，类似于通过游离自身肽的充分记录的静脉内耐受诱导。事实上，我们的数据显示， Ol-EV含有所有相关的髓磷脂Ag，并且在静脉内注射后，改善了Ag-1中正在进行的EAE。 依赖性的方式，表明Ol-EV可以是MS的通用治疗剂。 根据额外的初步数据，我们假设人和小鼠Ol-EV含有所有相关的髓鞘Ag， 在静脉内施用后将改善由各种髓鞘Ag诱导的EAE。我们还假设， 作用是Ag依赖性的，并由IFN-γ/IL-27/PD-L1轴介导。这一假设将在下面进行检验 具体目标：目标1。确定Ol-EV在几种EAE模型中的治疗功效。以来 该项目的意义是研究Ol-EV作为MS的潜在治疗，我们不知道相关的 Ag（s）在MS中的作用，我们将检验OL-EV/i. v.可以抑制任何髓鞘Ag诱导的EAE的假设，因为 OL-EV中存在所有相关的Ag。目标2.明确Ol-EV抑制EAE的机制。 我们的初步数据为Ol-EV/i. v.诱导耐受原性APC的假设提供了基础，所述耐受原性APC减少了免疫耐受性。 致病性Th细胞应答并通过表达免疫调节分子抑制EAE。目标3：研究 人Ol-EV在人髓磷脂Ag诱导的EAE中和在人源化小鼠中的作用。我们将优化 生产人Ol-EV，并检验人Ol-EV/i. v.具有足够的治疗功效的假设 在EAE模型中，以及在人源化小鼠中，以确定在小鼠中的发现是否在该类人系统中是一致的。

SUMMARY: Oligodendrocyte extracellular vesicles: a novel therapy for CNS autoimmunity. Current therapies for multiple sclerosis (MS) target the immune system in an antigen (Ag)-nonspecific manner, with potentialy serious side effects due to systemic immunosuppression. A longstanding goal in MS research is to devise an Ag-specific therapy that would suppress only harmful immune responses, while leaving the rest of the immune system intact. The prerequisite for Ag-specific therapy is identification of the target Ag. MS pathogenesis is widely believed to be driven by autoimmunity against myelin Ags. However, the relevant Ag(s) in MS remains speculative, with the possibility that these Ags differ among patients, and over time in the same patient. Numerous approaches for Ag-specific suppression of autoimmune neuroinflammation have been proven in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. These approaches rely on re- establishing peripheral tolerance for self-Ag by delivering the same self-Ag in a non-inflammatory context (eg. in PBS) via various routes, such as intravenous (i.v.), oral, or nasal. However, translation of these experimental strategies into MS therapy has been hampered by uncertainty about the relevant Ags in MS patients. In addressing this issue, we reasoned that if for tolerance induction we used oligodendrocyte (Ol)-derived extracellular vesicles (Ol-EVs), which naturally contain most or all of the myelin Ags, it would be unnecessary to identify the relevant myelin Ag(s) in each patient. Further, we also posited that i.v. injection of Ol-EVs will suppress EAE, similar to well-documented i.v. tolerance induction by free self-peptide. Indeed, our data show that Ol-EVs contained all the relevant myelin Ags and upon i.v. injection ameliorated ongoing EAE in an Ag- dependent manner, suggesting that Ol-EVs can be a universal therapeutic agent for MS. Based on these and additional preliminary data, we hypothesize that human and mouse Ol-EVs contain all relevant myelin Ags, and upon i.v. administration will ameliorate EAE induced by various myelin Ags. We additionally hypothesize that this effect is Ag-dependent and mediated by the IFN-/IL-27/PD-L1 axis. This hypothesis will be tested in the following specific aims: Aim 1. To determine the therapeutic efficacy of Ol-EVs in several EAE models. Since the significance of this project is to study Ol-EVs as a potential therapy for MS, and we do not know the relevant Ag(s) in MS, we will test the hypothesis that OL-EVs/i.v. can suppress EAE induced by any myelin Ag, because all the relevant Ags are present in OL-EVs. Aim 2. To define the mechanism of EAE suppression by Ol-EVs. Our preliminary data provide a basis for the hypothesis that Ol-EVs/i.v. induce tolerogenic APCs, which diminish pathogenic Th cell response and suppress EAE via expression of immunoregulatory molecules. Aim 3. To study the effects of human Ol-EVs in human myelin Ag-induced EAE, and in humanized mice. We will optimize production of human Ol-EVs, and test the hypothesis that human Ol-EVs/i.v. have adequate therapeutic efficacy in EAE models, and in humanized mice to determine if findings in mice are paralleled in this human-like system.