Mechanisms of regulatory T cell processes by IL-2

自身免疫性疾病是美国年轻和中年女性的主要死亡原因之一。 这些疾病是由自身反应性T细胞介导的，而T细胞自然包含在T调节细胞中 (Tregs)。由于Treg缺陷，IL-2受体(IL-2R)无功能突变导致自身免疫 生存和功能。这一发现得到了体内小鼠模型的证实，导致了广泛的 结论IL-2对Treg的存活起重要作用。然而，最近的数据表明，这一点过于简单化。我们的实验室 建立小鼠外周树突IL-2Rα链(CD25)条件性表达模型 消融了。CD25基因敲除的Tregs显示出不成比例的中央Tregs的丢失，这种Tregs是长期存在的 产生效应器以维持自身耐受性的循环树。还会显示批量挖空树 关键的Treg过程的中断，如增殖、存活、新陈代谢和抑制功能。 此外，在IL-2R突变动物中缺乏高度抑制的终末分化Tregs， 提示IL-2可能调节维持外周血细胞所需的高度抑制树突状细胞的形成 宽容。鉴于这些发现，IL-2信号控制的过程是必不可少的预防 自身免疫和对这一角色的理解可以为操纵这一群体提供治疗途径。目标 1将确定IL-2对Treg亚群的存活、增殖、功能和代谢的影响。 利用流式细胞术和体外检测，将增殖、凋亡、存活、功能和代谢 在带有和不带有IL-2信号的Tregs亚群中进行检查。这一目的将使IL-2在多大程度上 调节Treg亚群中的细胞过程，以进一步定义IL-2维持Treg的方式 人口。目的2将评估IL-2在Treg分化和异质性中的作用。由于缺陷 在IL-2的设置下观察Treg的分化情况，这一目的将采用过继转移的Treg 有和没有IL-2信号的亚群，以确定IL-2如何调节从cTregs到eTregs的发展。 目标3将定义cTregs和cTregs中依赖IL-2的转录和表观遗传过程 ETregs。这一目标将利用RNAseq和atac-seq等高吞吐量技术来关联 在Treg亚群中，由于IL-2信号或缺乏IL-2信号而引起的表观遗传和转录变化。通过 定义IL-2依赖的途径和它们之间不同的细胞过程，这些发现将是 与Aim 1中的那些整合在一起，以提供IL-2在调节每个Treg的细胞过程中的明确作用 子集。这项联谊研究的主要目标是定义IL-2驱动的协调Treg的过程 存活率和动态平衡与理解这种细胞因子的治疗应用密切相关 与理解自身免疫性疾病具有广泛的相关性。

Autoimmune disease is one of the leading causes of death for young and middle-aged women in the US. These diseases are mediated by autoreactive T cells, which are naturally contained by T regulatory cells (Tregs). Non-functional mutations in the IL-2 receptor (IL-2R) lead to autoimmunity due to deficiencies in Treg survival and function. This finding is corroborated by in vivo mouse models, leading to the widespread conclusion that IL-2 is important for Treg survival. However, recent data indicates this is oversimplified. Our lab studies a mouse model in which the alpha chain (CD25) of the IL-2R on peripheral Tregs is conditionally ablated. CD25 knockout Tregs demonstrate a disproportionate loss of central Tregs, which are long-lived circulating Tregs that give rise to effectors to maintain self-tolerance. Bulk knockout Tregs also display disruptions in critical Treg processes such as proliferation, survival, metabolism and suppressive function. Additionally, there is an absence of highly suppressive terminally differentiated Tregs in IL-2R mutant animals, indicating IL-2 may regulate the development of highly suppressive Tregs required for maintain peripheral tolerance. Given these findings, IL-2 signaling controls processes that are essential for the prevention of autoimmunity and understanding this role can provide therapeutic avenues to manipulate this population. Aim 1 will determine the effects of IL-2 on survival, proliferation, function and metabolism in Treg subsets. Using flow cytometry and in vitro assays, proliferation, apoptosis, survival, function and metabolism will be examined in Tregs subsets with and without IL-2 signaling. This aim will inform the extent to which IL-2 regulates cellular processes in Tregs subsets to further define the way by which IL-2 maintains Treg populations. Aim 2 will evaluate the role of IL-2 in Treg differentiation and heterogeneity. Due to defects observed in the differentiation of Tregs in the setting of IL-2, this aim will use adoptively transferred Treg subsets with and without IL-2 signaling to determine how IL-2 regulates development of eTregs from cTregs. Aim 3 will define the distinct IL-2 dependent transcriptional and epigenetic processes in cTregs versus eTregs. This aim will harness high throughput techniques such as RNAseq and ATAC-seq to correlate epigenetic and transcriptional changes as a consequence of IL-2 signaling, or lack thereof, in Treg subsets. By defining IL-2-dependent pathways and cellular processes that differ between them, these findings will be integrated with those in aim 1 to provide a clear role for IL-2 in regulating the cellular processes in each Treg subset. The main objective of this fellowship research is to define IL-2 driven processes coordinating Treg survival and homeostasis that are acutely relevant for understanding therapeutic applications of this cytokine and broadly relevant for understanding autoimmune disease.