MicroRNA-mediated control of immune responses and tolerance

与转录因子一样，microRNAs(MiRNAs)是一类短的调节性非编码RNA，以其 在器官发育、细胞分化、动态平衡和功能中的作用已被广泛研究。 因为它们在控制决定发育结果的不同基因集的表达方面所起的作用 免疫细胞群体的转变或细胞激活状态。以前，我们已经确定了一个 重要的miRNA家族，miR-23~27~24簇，在调节分化和 多种CD4辅助T(Th)细胞系以及调节性T(Treg)细胞的功能。我们的工作表明 在CD4T细胞中，miR-23~27~24的适当基因调控是确保最佳平衡的关键 在豁免权和宽容之间。T细胞miR-23~27~24簇缺失导致卵泡功能失调 小鼠衰老时的辅助性(TFH)细胞反应和Th2诱导的严重呼吸道炎症 不同的过敏原。另一方面，这个miRNA家族成员的过度表达也会 通过促进促炎细胞因子的产生而导致自身免疫的发展 效应T(TJeff)细胞以及破坏Treg细胞的动态平衡和功能。考虑到许多人 我们以前的工作中发现的miRNA家族靶标也已知在其他免疫细胞中发挥作用 在人群中，miR-23~27~24簇可能对免疫系统产生更广泛的影响，而不仅仅是它们在 调节CD4T细胞免疫。在这里，我们提出了一项多方面的研究，利用遗传、生化、 免疫学方法和全动物实验综合检测分子 以及miR-23簇介导的免疫调节的细胞机制。尤其是，虽然我们将 扩大我们对这个miRNA家族在T细胞免疫中的研究力度，将新的重点放在CD8 T细胞介导的 免疫反应，我们还将研究它们在Tfh细胞和B细胞中的潜在新作用，这两个细胞是至关重要的 用于建立生发中心(GC)反应和由此产生的体液免疫。接下来，通过组合 RNA-SEQ、CHIP-SEQ方法利用新开发的IR-Clash技术，我们将探索可能的 通过鉴定miR-23簇依赖免疫调节的分子机制 以miR-23簇依赖的方式调控的基因，并通过识别 由miR-23星系团直接控制。集体而言，当前提案的总体目标不仅是 建立一个强大的模型来剖析细胞分化、功能和 适应性免疫系统中的动态平衡，而且还建立了一个坚实的基础，用来针对 MIR-23~27~24家族用于对抗感染和广泛的人类免疫性疾病。

Like transcription factors, microRNAs (miRNAs), a class of short regulatory non-coding RNAs known for their role in organ development, cellular differentiation, homeostasis, and function, have been extensively studied for their roles in controlling expression of different sets of genes that dictates the outcome of developmental transitions or cellular activation status of the immune cell populations. Previously, we have identified an important miRNA family, miR-23~27~24 clusters that play a diverse role in regulating the differentiation and function of multiple CD4+ helper T (Th) cell lineages as well as regulatory T (Treg) cells. Our work has shown that proper gene regulation by the miR-23~27~24 in CD4+ T cells is crucial to ensure the optimal balance between immunity and tolerance. Loss of miR-23~27~24 clusters in T cells resulted in dysregulated follicular helper (Tfh) cell responses when mice aged and severe Th2-driven airway inflammation upon challenges of different allergens. On the other hand, excessive expression of members of this miRNA family would also lead to the development of autoimmunity through both promoting the proinflammatory cytokine production by effector T (Teff) cells as well as impairing Treg cell homeostasis and function. Considering that many of the miRNA family targets identified in our previous work are also known to function in other immune cell populations, miR-23~27~24 clusters likely have a broader impact on the immune system beyond their role in regulating CD4+ T cell immunity. 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. In particular, while we will expand our efforts in studying this miRNA family in T cell immunity with a new focus on CD8+ T cell-mediated immune responses, we will also examine their potential new roles in both Tfh cells and B cells that are crucial for establishment of germinal center (GC) reactions and the resultant humoral immunity. Next, by combining RNA-seq, ChIP-seq approaches with newly developed IR-CLASH technology, 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 cluster. Collective, the over-arching goal of the current proposal is to not only establish a powerful model to dissect the molecular orchestration of cellular differentiation, function, and homeostasis in the adaptive immune system but also build a solid foundation with which to target the miR-23~27~24 family to combat infections and a wide array of human immunological diseases.