Role of microRNAs in regulatory T cell-mediated immunological tolerance and T cel

描述（由申请人提供）：许多microRNA （miRNA）是一类短调控非编码rna，以其在器官发育、细胞分化、体内平衡和功能中的作用而闻名，最近被证明在调节免疫反应中起关键作用。我们之前已经证明了miRNA通路在控制调节性T （Treg）细胞稳态和功能中不可或缺的作用。在Treg细胞中高表达的mirna中，miR-155和miR-146a分别在维持Treg细胞正常稳态中起关键作用，更重要的是调节其对Th1炎症的抑制功能。然而，由于携带缺乏miRNA的Treg细胞的小鼠疾病表型的复杂性和严重性不能完全归因于上述单个miRNA的缺失，因此控制Treg细胞生物学其他特征所必需的其他miRNA需要进一步阐明。与上面描述的miR-155和miR-146a一样，我们发现miR-23簇在Treg细胞中至少部分以Foxp3依赖的方式被高度上调。此外，激活后，Treg细胞和Tcon细胞之间miR-23簇的表达差异变得更大，因为它们在Treg细胞中进一步上调，而在Tcon细胞中下调。在这里，我们提出了一项多方面的研究，采用遗传、生化、免疫学和全动物实验的方法，全面研究miR-23簇介导的免疫调节的分子和细胞机制。首先，通过产生携带miR-23集群条件等位基因的小鼠，这种功能缺失方法将允许我们检查miR-23集群在生理和自身免疫环境中调节Treg细胞介导的免疫耐受中的作用。接下来，立即获得整个miR-23a集群以及集群内单个miRNA成员条件过表达转基因的小鼠，将有机会系统地检查miR-23集群在各种环境下控制T细胞免疫中的作用。最后，我们将通过鉴定以miR-23簇依赖方式调节的基因和鉴定由miR-23簇直接控制的靶标，探索miR-23簇依赖免疫调节的假定分子机制。拟议的研究将极大地扩展我们对mirna介导的免疫调节的基础知识，并为开发操纵Treg细胞和效应T细胞功能的策略提供进一步的见解，作为治疗人类免疫性疾病的新治疗方法。

DESCRIPTION (provided by applicant): Numerous microRNA (miRNA), a class of short regulatory non-coding RNAs known for their role in organ development, cellular differentiation, homeostasis, and function, have been recently demonstrated to be pivotal in regulating immune responses. We have previously shown an indispensable role of the miRNA pathway in controlling regulatory T (Treg) cell homeostasis and function. Among miRNAs highly expressed in Treg cells, miR-155 and miR-146a play pivotal roles in maintaining normal Treg cell homeostasis and more importantly regulating their suppressor function to Th1 inflammation, respectively. Nonetheless, because the complexity and the severity of the disease phenotypes in mice harboring Treg cells devoid of miRNA cannot be attributed entirely to the loss of aforementioned individual miRNAs, additional miRNAs essential for controlling other features of Treg cell biology require further elucidation. Like miR-155 and miR-146a described above, miR-23 clusters were found to be highly upregulated in Treg cells at least partially in a Foxp3 dependent manner. Moreover, the differences in the expression of miR-23 clusters between Treg cells and Tcon cells became even larger upon activation as they were further upregulated in Treg cells while downregulated in Tcon cells. Here, we propose a multifaceted study employing genetic, biochemical, immunological approaches and whole animal experimentation to comprehensively examine the molecular and cellular mechanisms underlying miR-23 cluster-mediated immune regulation. First, by generating mice harboring conditional alleles of miR-23 clusters, this loss-of-function approach will allow us to examine the role of miR-23 clusters in regulating Treg cell-mediated immunological tolerance in both physiological and autoimmune settings. Next, the immediate availability of mice harboring conditional over-expressing transgenes of the whole miR-23a cluster as well as individual miRNA member within the cluster will afford the opportunity to systematically examine the role of miR-23 cluster in controlling T cell immunity in various settings. Finally, we will explore the putative molecular mechanisms underlying miR-23 cluster-dependent immune regulation through identification of genes that are regulated in miR-23 cluster-dependent manner and through identification of targets that are directly controlled by miR-23 clusters. The proposed studies will greatly extend our fundamental knowledge of miRNA-mediated immune regulation and provide further insights into the development of strategies to manipulate Treg cell and effector T cell function as novel therapeutic approaches for treating human immunological diseases.