MicroRNA-mediated control of immune responses and tolerance

与转录因子一样，microRNA (miRNA) 是一类短调控非编码 RNA，以其独特的功能而闻名。 在器官发育、细胞分化、稳态和功能中的作用已被广泛研究 因为它们在控制不同基因组表达中的作用，这些基因决定了发育的结果 免疫细胞群的转变或细胞激活状态。此前，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) 细胞谱系以及调节性 T (Treg) 细胞的功能。我们的工作已经表明 CD4 T 细胞中 miR-23~27~24 的适当基因调节对于确保最佳平衡至关重要 免疫与耐受之间。 T 细胞中 miR-23~27~24 簇的丢失导致卵泡失调 当小鼠衰老和严重 Th2 驱动的气道炎症面临以下挑战时，辅助细胞 (Tfh) 的反应 不同的过敏原。另一方面，该 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导致自身免疫的发展 效应 T (Teff) 细胞以及损害 Treg 细胞稳态和功能。考虑到许多 我们之前的工作中发现的 miRNA 家族靶点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，超出其在免疫系统中的作用。 调节CD4 T细胞免疫。在这里，我们提出了一项采用遗传、生化、 免疫学方法和整体动物实验来全面检查分子 以及 miR-23 簇介导的免疫调节的细胞机制。特别是，虽然我们将 扩大我们在 T 细胞免疫中研究这个 miRNA 家族的努力，新的重点是 CD8 T 细胞介导的 免疫反应，我们还将检查它们在 Tfh 细胞和 B 细胞中的潜在新作用，这至关重要 用于建立生发中心（GC）反应和由此产生的体液免疫。接下来，通过结合 RNA-seq、ChIP-seq 采用新开发的 IR-CLASH 技术，我们将探索假定的 通过鉴定 miR-23 簇依赖性免疫调节的分子机制 以 miR-23 簇依赖性方式并通过识别靶标来调节基因 直接受miR-23簇控制。总的来说，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、功能和细胞的分子编排 适应性免疫系统的稳态，同时也为靶向免疫系统奠定了坚实的基础 miR-23~27~24 家族可对抗感染和多种人类免疫疾病。

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.