Role of miRNA Dysregulation on T Cell Differentiation and Function in MS

摘要 多发性硬化症(MS)是一种免疫介导的中枢神经系统(CNS)脱髓鞘疾病，可导致 严重的神经缺陷。该病的病因尚不清楚，免疫和神经退行性机制尚不清楚 该病的病理生理学基础尚不清楚，目前的治疗方法仅部分有效。 延缓疾病的发展。迫切需要研究新的机制，这可能有助于 疾病易感性和该病的病理生理学。为此，我的实验室进行了大量的miRNA 未经治疗的MS患者的幼稚和效应/记忆CD4T细胞的特征研究以确定miRNA是否可能起作用 易患疾病的易患疾病或进展的MiRNA通过RNA干扰途径负向调节基因表达， 因此在调节细胞中特定蛋白质的水平方面起着关键作用。我们已经确定了至少两条路径 在多发性硬化症患者中发生改变，这可能有助于他们患多发性硬化症的易感性。首先，miRNAs靶向成分 在MS患者中，Th2细胞分化途径中的T细胞升高，偏向分化为促炎 Th1细胞。第二，针对转化生长因子β信号通路的miRNA限制了调节性T细胞的分化。因此， 在MS患者中观察到的CD4T细胞缺陷可能至少部分是由miRNA调节失调所介导的。在这份提案中， 我们将解决以下问题。目的1：多发性硬化症患者的CD4T细胞分化能力是否存在缺陷 以一种依赖miRNA的方式进入Tregs？初步数据显示，MS患者的幼稚CD4T细胞未能 有效地分化成树。使用miRNA抑制剂，我们将确定这种分化为Tregs的失败是否 依赖于MS患者中特定miRNAs的过度表达以及Treg分化能否正常化MS 患者幼稚的CD4T细胞。目的2：MS相关miRNAs的过度表达如何影响发育和 中枢神经系统自身免疫在小鼠模型中的进展？利用EAE，靶向CD4T细胞分化的miRNAs的作用 转化为效应器和调节性T细胞将在体内进行分析，以补充人体的体外实验。目标3：可以 针对效应性和调节性CD4T细胞的miR-128的表达水平调节CNS的风险 自体免疫？我们发现miR-128靶向Th2型和转化生长因子β信号通路中的蛋白，促进 Th1细胞的分化与Tregs的发展使用CD4特异性miR-128-/-小鼠和小鼠 在CD4T细胞中过表达miR-128，我们将确定在CD4T细胞中丢失miR-128是否会将CNS的易感性降至最低 自身免疫，使CD4T细胞分化为效应细胞和调节细胞，因此是一种潜在的治疗方法 目标是纠正MS中的效应性和调节性T细胞缺陷。相反，我们将使用过表达miR-128的小鼠 在CD4T细胞中确定miR-128是否足以扭曲CD4T细胞的分化并增加发生的风险 中枢神经系统自身免疫性。这项研究将检验这样一种假设，即幼稚的CD4T细胞中的miRNA失调是潜在的 中枢神经系统自身免疫中的危险因素，可作为治疗靶点使效应和调节性CD4T细胞正常化 功能。如果我们的假设是正确的，基于miRNA的治疗可能不仅可以预防易感人群的中枢神经系统自身免疫 但可改善MS患者的自身反应性T细胞。

Abstract Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS) which can result in severe neurological deficits. The cause of the disease is unknown, the immune and neurodegenerative mechanisms underlying the pathophysiology of the disease are poorly understood, and current therapies are only partially effective at slowing disease progression. There is a tremendous need to investigate novel mechanisms that may be contributing to disease susceptibility and the pathophysiology of this disease. To this end, my laboratory has performed a large miRNA profiling study on naïve and effector/memory CD4 T cell in untreated MS patients to determine if miRNA may contribute to disease susceptibility or progression. MiRNA negatively regulate gene expression via the RNA interference pathway, and thus play a key role modulating the level of specific proteins in cells. We have identified at least two pathways that are altered in MS patients that may contribute to their susceptibility to develop MS. First, miRNAs targeting components of the Th2 cell differentiation pathway were elevated in MS patients T cells, skewing differentiation into pro-inflammatory Th1 cells. Second, miRNAs targeting the TGFβ signaling pathway limited the differentiation of regulatory T cells. Thus, the defects observed in MS patients CD4 T cells may be at least partially mediated by miRNA dysregulation. In this proposal, we will address the following questions. Aim 1: Are MS patients’ CD4 T cells defective in their ability to differentiate into Tregs in a miRNA-dependent manner? Preliminary data indicates that naïve CD4 T cells from MS patients fail to efficiently differentiate into Tregs. Using miRNA inhibitors, we will determine if this failure to differentiate into Tregs is dependent on specific miRNAs over-expressed in MS patients and whether Treg differentiation can be normalized MS patients’ naïve CD4 T cells. Aim 2: How does over-expression of MS-associated miRNAs affect the development and progression of CNS autoimmunity in a mouse model? Using EAE, the role of miRNAs that target CD4 T cell differentiation into effector and regulatory T cells will be analyzed in vivo to complement the human in vitro experiments. Aim 3: Can expression level of miR-128, which targets both effector and regulatory CD4+ T cells, modulate the risk of CNS autoimmunity? We found that miR-128 targets proteins in the Th2 and TGFβ signaling pathways, promoting the differentiation of Th1 cells and preventing the development of Tregs. Using CD4-specific miR-128-/- mice and mice overexpressing miR-128 in CD4 T cells, we will determine if loss of miR-128 in CD4 T cells minimizes susceptibility to CNS autoimmunity, normalizes CD4 T cell differentiation into effector and regulatory cells, and thus, is a potential therapeutic target to correct both effector and regulatory T cell defects in MS. In contrast, we will use mice overexpressing miR-128 in CD4 T cells to determine if miR-128 is sufficient to skew CD4 T cell differentiation and enhance the risk of developing CNS autoimmunity. This study will test the hypothesis that miRNA dysregulation in naïve CD4+ T cells is an underlying risk factor in CNS autoimmunity that can be therapeutically targeted to normalize effector and regulatory CD4 T cell function. If our hypothesis is correct, miRNA-based therapies may not only prevent CNS autoimmunity in susceptible individuals, but ameliorate autoreactive T cells in patients with MS.