Treg development and function controlled by cis-regulatory circuits

项目摘要 调节性T细胞（Treg）在维持免疫系统稳态和预防免疫功能紊乱中起着重要作用。 自身免疫和免疫病理学。Treg功能受损与多种自身免疫性疾病有关 包括1型糖尿病和多发性硬化症。另一方面，人们认为肿瘤内Treg细胞的富集 成为有效抗肿瘤免疫反应的屏障。Treg细胞系的发育和维持 依赖于转录因子Foxp 3，因为功能缺失突变导致严重的淋巴组织增生 小鼠和人类的疾病。因此，了解Foxp 3诱导和稳定性的机制 可能导致自身免疫性疾病和癌症的新疗法的发展。此前，郑博士与 他的同事在Foxp 3基因座上鉴定了三个进化上保守的顺式调控元件， 在Treg分化或维持中的独特作用。为了扩大这一研究领域，郑博士的研究小组将利用 一种基于CRISPR/Cas9的方法，称为CREST-seq（通过平铺-缺失顺式调控元件扫描， 测序）进行Foxp 3基因座附近的远端顺式元件的无偏筛选和功能评估。 初步研究表明，Foxp 3的调控可能涉及多达50个顺式调控元件， 表情对这些新的顺式元件的深入表征将促进对 Foxp 3表达的调节回路。许多研究对数百万候选人进行了注释 在Tibetan中有数千个基因的调控元件，但对这些元件如何作用的理解是不完整的。 控制着千碱基甚至百万碱基以外的目标基因。全基因组的初步研究 在TcB中的染色体环形成了一组远端DNA环，这些DNA环可以潜在地调节Treg 特征基因此外，这些数据表明Foxp 3在促进远端DNA成环中的新作用。到 为了更好地了解顺式调节回路如何控制Treg的分化和功能，郑博士的研究小组将 通过基于平铺缺失的遗传筛选鉴定和表征控制Foxp 3表达的顺式元件 (Aim 1）探索远端增强子如何通过染色体调控调节性T细胞中的基因表达 循环（目标2）。此外，他们将研究Foxp 3是否有助于染色体环的建立， 维持Treg谱系由于Treg细胞与自身免疫性疾病和癌症直接相关， 这项研究将深入了解Treg发育和功能的分子机制，并提供新的 为治疗目的操纵TdR的机会。

Project Summary Regulatory T cell (Treg) plays a critical role in maintaining immune system homeostasis and preventing autoimmunity and immunopathology. Compromised Treg function is linked to multiple autoimmune diseases including type 1 diabetes and multiple sclerosis. On the flip side, enrichment of Treg cells within tumors is thought to be a barrier to effective anti-tumor immune response. The development and maintenance of Treg cell lineage are dependent on transcription factor Foxp3, as loss of function mutations lead to severe lymphoproliferative disease in mice and humans. Thus, understanding the mechanisms that govern Foxp3 induction and stability may lead to the development of novel therapies for autoimmune disease and cancer. Previously, Dr. Zheng and colleagues identified three evolutionarily conserved cis-regulatory elements at the Foxp3 locus, which play unique roles in Treg differentiation or maintenance. To expand this line of research, Dr. Zheng’s group will use a CRISPR/Cas9 based approach named CREST-seq (cis-regulatory element scan by tiling-deletion and sequencing) to perform unbiased screen and functional assessment for distal cis-elements near the Foxp3 locus. A preliminary study showed there are potentially up to 50 cis-regulatory elements involved in the control of Foxp3 expression. In-depth characterization of these new cis-elements will advance the understandings on the regulatory circuitry of Foxp3 expression. Numerous studies generated annotations on millions of candidate regulatory elements for thousands of genes in Tregs, but understanding is incomplete on how these elements control their target genes that are kilo-bases or even mega-bases away. Preliminary studies on genome-wide chromosome looping in Tregs generated a collection of distal DNA loops that can potentially regulate Treg signature genes. Furthermore, these data suggest a novel role for Foxp3 in facilitating distal DNA looping. To better understand how cis-regulatory circuitry control Treg differentiation and function, Dr. Zheng’s group will identify and characterize the cis-elements that control Foxp3 expression by a tiling deletion based genetic screen (Aim 1) and explore how distal enhancers regulate gene expression in regulatory T cell through chromosome looping (Aim 2). Furthermore, they will investigate if Foxp3 facilitates chromosome looping to establish and maintain the Treg lineage. Since Treg cell is directly related to autoimmune diseases and cancer, Dr. Zheng’s study will provide insight into the molecular mechanisms of Treg development and function and offer new opportunities to manipulate Tregs for therapeutic purposes.