Metabolic regulators of Treg/Th17 balance in CNS autoimmunity

项目摘要/摘要 自身免疫组织炎症是由效应T细胞和调节性T细胞之间的平衡决定的。 在自身免疫反应中，效应器T细胞过度增殖，产生促炎细胞因子 并抑制导致炎症的调节性T细胞的扩增和生成。细胞因子发挥作用 在这一过程中起着关键作用，但其他因素如新陈代谢和身体因素如氧分压， 组织微环境中的pH和空间在调节效应器和Treg中起着同样重要的作用 平衡。然而，组织中T细胞新陈代谢的分析是具有挑战性的，因为 可用的细胞数量和当前的代谢技术。我们开发了一种新的计算方法 一种名为Compass的算法，可以使用单细胞RNAseq数据预测细胞的代谢状态。 在这个工具的帮助下，我们发现多胺代谢是Th17致病的主要驱动因素 细胞。在此，我们观察到Odc1抑制可以通过增加线粒体的 线粒体复合体稳定基因对效应T细胞功能的潜在影响。此外， 我们的初步数据表明，多胺途径(限速酶， Odc1)和表观基因组修饰符JMJD3/KDM6B。我们还提供了证据表明，对 Odc1-JMJD3轴通过化学抑制物或基因缺失修饰转录组和表观基因组 (基因组可及性)Th17细胞支持Tregs与中枢神经系统组织炎症的相关性 实验性自身免疫性脑脊髓炎(EAE)。根据这些数据，我们假设 多胺途径是效应器与Treg分化的关键代谢和表观遗传调节因子 从而影响组织炎症的发展。该途径的关键元件Odc1- JMJD3轴是一个检查点，可以受到细胞因子的调节，并可以感知环境 低氧等信号，随后调整T细胞的代谢和表观基因组状态以 调节效应器与调节性T细胞平衡。我们将在两个目标上检验这一假设：1)确定 多胺生物合成如何限制线粒体OXPHOS并促进电子逆向传输 在EAE期间发炎的中枢神经系统中冲击效应器与Treg的发展；2)确定多胺 代谢酶Odc1干扰JMJD3功能调节T细胞基因组可及性 在EAE发展过程中，支持Th17而不是Treg发育的细胞。多胺代谢 通路可能在T细胞生物学中有更广泛的意义。因此，我们将重点关注 在Th17/Treg平衡的背景下，炎症中枢Odc1-JMJD3轴。拟议的研究具有很高的 与人类疾病相关，反映在多种疾病之间的显著重叠(约25%) 硬化症存在差异调节效应器Th17和Treg分化的变异和基因。

PROJECT SUMMARY/ ABSTRACT Autoimmune tissue inflammation is dictated by a balance between effector and regulatory T cells. During an autoimmune reaction, effector T cells hyper proliferate, produce pro-inflammatory cytokines and suppress expansion and generation of regulatory T cells resulting in inflammation. Cytokines play a key role in the process, but other factors such as metabolism and physical factors like oxygen tension, pH and space in tissue microenvironment play an equally important role in regulating effector vs. Treg balance. However, the analysis of T cell metabolism in tissue is challenging due to limitations of available cell numbers and current metabolic techniques. We developed a novel computational algorithm called Compass that can predict metabolic state of cells using single cell RNAseq data. Facilitated by this tool, we identified polyamine metabolism as a major driver of pathogenicity of Th17 cells. Herein we observed that Odc1 inhibition can regulate mitochondrial function by increasing mitochondrial complex stability genes with potential consequences in effector T cell function. Further, our preliminary data suggests a connection between the polyamine pathway (rate limiting enzyme, Odc1) and an epigenome modifier, JMJD3/Kdm6b. We also provide evidence that inhibition of the Odc1-JMJD3 axis by chemical inhibitors or genetic deletion modifies the transcriptome and epigenome (genome accessibility) of Th17 cells in favor of Tregs with relevance in tissue inflammation in CNS in experimental autoimmune encephalomyelitis (EAE). Based on these data we hypothesize that polyamine pathway is a critical metabolic and epigenetic regulator of effector vs. Treg differentiation and thereby affects development of tissue inflammation. The key element of the pathway, Odc1- JMJD3 axis is a checkpoint that can be regulated by cytokines and can sense environmental cues such as hypoxia and subsequently adjust metabolic and epigenomic state of T cells to regulate effector vs. regulatory T cell balance. We will test this hypothesis in two aims: 1) determine how polyamine biosynthesis restricts mitochondrial oxphos and promotes reverse electron transport to impact effector vs. Treg development in inflamed CNS during EAE; 2) determine whether polyamine metabolism enzyme Odc1 interferes with JMJD3 function to modulate the genome accessibility of T cells favoring Th17 over Treg development during EAE development. The polyamine metabolism pathway likely has broader implications in T cell biology. Hence, we will focus on the relevance of the Odc1-JMJD3 axis in inflamed CNS in the context of Th17/Treg balance. The proposed study is highly relevant in human diseases as reflected by a significant overlap (about 25%) between multiple- sclerosis risk variants and genes that differentially regulate effector Th17 vs. Treg differentiation.