MICRORNA CONTROL OF INFLAMMATORY AND REGULATORY T CELLS IN CENTRAL NERVOUS SYSTEM AUTOIMMUNITY

项目摘要/摘要 炎性T细胞和调节性T细胞之间的适当平衡对维持免疫至关重要 动态平衡和预防自身免疫疾病，包括多发性硬化症(MS)及其动物模型， EAE。尽管已知T辅助细胞亚群的分化和致病性是由特定的 转录因子和细胞因子，控制这些细胞平衡的microRNAs的作用并不是很好 明白了。我们最近发现了microRNA，MIR-21在促进炎症方面的一个重要作用 小鼠和人的Th17/Th1细胞和抑制调节性TR35细胞。我们的初步数据表明 MIR-21通过这些细胞类型介导EAE中的组织炎症。具体地说，我们发现在Th17细胞中，MIR- 21靶向Foxo1，解除IL-23R和IL-1R对Foxo1的抑制，增强对IL-1的反应性 23和IL-1β，并促进Th17致病。MIR-21还促进GM-CSF在体内的表达 通过靶向Foxo1-IL-1R轴分化Th1细胞。MIR-21的缺失干扰细胞的表达 Th17/Th1效应细胞因子GM-CSF体内存在，并具有显著的抗EAE作用。另外，我们初步的 数据显示，MIR-21可能通过以下途径阻止调节性TR35细胞的发展而促进自身免疫 靶向IL-12p35，这是一个由细胞因子IL-35共享的亚基。与我们在老鼠身上的发现类似，我们发现 在人类中，MIR-21促进Th17分化，同时抑制TR35细胞。有趣的是，我们还 发现MS患者T细胞及其他Th1/Th17型细胞因子MIR-21的表达增加，而干扰素-β、a 多发性硬化症的一线治疗，抑制T细胞中的MIR-21。最重要的是，我们发现来自干扰素-β的CD4+T细胞 应答者表达的MIR-21水平较低，而非应答者的水平与 未经治疗的病人。然而，MIR-21在调节EAE和EAE中Th17/Th1和TR35细胞的确切作用 人类，特别是多发性硬化症患者，目前尚不清楚。在这项提案中，我们将调查MIR-21是如何监管 炎性T细胞和抗炎T细胞在EAE和MS中的平衡 MIR-21促进Th17/Th1致病功能及其抑制的分子机制 EAE中的调节性TR35细胞。在目标2中，我们将从分子上定义MIR-21介导的机制 促进Th17细胞和抑制调节性TR35细胞，并调节其他T辅助细胞亚群 人类。鉴于我们在人类T辅助细胞和多发性硬化症患者中的初步数据与小鼠细胞相似 和EAE小鼠，可能相同的关键致病途径MIR-21介导的调节EAE的 也参与了MS的发病机制。因此，在目标3中，我们将研究MIR-21通路 影响MS患者炎性Th17/Th1和调节性T细胞的平衡及是否调节 通过这些途径的改变是对治疗的反应。对这些途径的更好理解将会有 MS免疫机制导航的重要意义及其与治疗效果的关系。

Project Summary/Abstract An appropriate balance between inflammatory and regulatory T cells is critical to maintaining immune homeostasis and preventing autoimmune diseases, including multiple sclerosis (MS) and its animal model, EAE. Although the differentiation and pathogenicity of T helper subsets is known to be regulated by specific transcription factors and cytokines, the role of microRNAs that control the balance of these cells is not well understood. We recently uncovered an important role for the microRNA, Mir-21 in promoting inflammatory Th17/Th1 cells and inhibiting regulatory Tr35 cells in both mice and humans. Our preliminary data suggest that Mir-21 mediates tissue inflammation in EAE via these cell types. Specifically, we found that in Th17 cells, Mir- 21 targets Foxo1, relieves IL-23R and IL-1R from Foxo1-mediated inhibition, enhances responsiveness to IL- 23 and IL-1β, and promotes Th17 pathogenicity. Mir-21 also promotes GM-CSF expression within differentiated Th1 cells by targeting the Foxo1-IL-1R axis. Loss of Mir-21 interferes with the expression of the Th17/Th1 effector cytokine GM-CSF in vivo and confers striking EAE resistance. In addition, our preliminary data show that Mir-21 may promote autoimmunity by preventing the development of regulatory Tr35 cells by targeting IL-12p35, a subunit shared by the cytokine IL-35. Analogous to our findings in mice, we have found that Mir-21 promotes Th17 differentiation, while inhibiting Tr35 cells, in humans. Interestingly, we have also found increased expression of Mir-21 in T cells and other Th1/Th17 cytokines in MS patients, and that IFN-β, a first-line therapy for MS, inhibits Mir-21 in T cells. Most importantly, we found that CD4+ T cells from IFN-β responders expressed lower levels of Mir-21, and that non-responders had indistinguishable levels from untreated patients. However, the exact role of Mir-21 in the regulation of Th17/Th1 and Tr35 cells in EAE and humans, specifically MS patients, is not known. In this proposal, we will investigate how Mir-21 regulates the balance of inflammatory and anti-inflammatory T cells in EAE and MS. In Aim 1, we will investigate the molecular mechanisms by which Mir-21 promotes the pathogenic functions of Th17/Th1 and inhibition of regulatory Tr35 cells in EAE. In Aim 2, we will molecularly define the mechanisms by which Mir-21 mediates promotion of Th17 cells and inhibition of regulatory Tr35 cells, and modulates other T helper subsets in humans. Given that our preliminary data in human T helper cells and MS patients is analogous to murine cells and EAE mice, it is possible that the same critical pathogenic Mir-21-mediated pathways modulating EAE may also be involved in the MS pathogenesis. Therefore, in Aim 3, we will investigate whether Mir-21 pathways influence the balance of inflammatory Th17/Th1 and regulatory T cells in MS patients and whether regulation by these pathways is altered in response to therapy. A better understanding of these pathways will have important implications for navigating immune mechanisms in MS and how they relate to therapeutic efficacy.