How beta-catenin expands Foxp3+RORgammat+ Pro-inflammatory T-regulatory cells

摘要 调节性T细胞(Tregs)的可塑性和功能多样性对维持健康至关重要 免疫，但它也被利用于疾病。我们已经描述了表达高水平β的Treg的子集- 连环素和促进炎症。在炎症性肠病中，这些Treg的频率增加。 (和小鼠结肠炎)、结肠癌(和小鼠息肉病)，以及多发性硬化症(和小鼠EAE)。 显性活性β-连环蛋白的表达或Tcf-1在Treg中的去除都促进了Rorγ的表达。 Th17谱系的规范转录因子，并促进Th17分化签名。在 在健康小鼠的肠系膜淋巴结(MLN)中，我们鉴定了至少5个转录上明显不同的激活 一簇簇的特雷格。这些簇中的一个由RoRγt的表达定义，并且具有显著的Th17 分化特征。在Tcf-1缺乏的Treg中，Th17分化谱扩展到所有其他 集群，RoRγt集群的频率增加。Tcf-1缺乏Tregs，尽管Th17 例如，抑制T细胞，但它们未能抑制炎症。这表明Treg出现了分叉。 抑制功能，并回避了一个问题，即它是否涉及TCF-1和Foxp3之间的合作。 我们发现，TCF-1和Foxp3共同结合了参与T细胞激活和修复的基因的增强子元件 Th17分化。β-连环蛋白在这些增强子上诱导新的可及染色质区域 上调相关基因的表达。此外，E-box结合蛋白Heb可以协同工作 通过Tcf-1和潜在的Foxp3来调节这些基因，因为Treg特异性地消融Tcf-1和Foxp3 HEB(但不是每一种都单独)拯救与β-连环蛋白相关的炎症和自身免疫病理 在Tregs中激活。Heb一贯调控RoR-γ-t，抑制Foxp3和外周Treg的发展。我们的 这些发现与FoxP3在某种背景下直接激活或抑制转录的概念是一致的--以及 依赖合作伙伴的方式。它们进一步涉及β-catenin、tcf-1和heb与foxp3合作以 自主规范多样化的Treg抑制活动。基于这些发现，我们假设， Wnt/β-catenin信号通路通过控制TREG抑制功能和多样性 Foxp3和Heb选择Tcf-1结合的染色质位点。为了具体地解决这一假设 目的1我们将确定β-连环蛋白和Tcf-1在制备foxp3结合的表观遗传格局中的作用。 以及在塑造Treg细胞类型多样性方面的作用。在特定的目标2中，我们将确定分泌的Wnt配体在 定义结肠浸润性树的功能特性。拟议的研究将阐明基本的共同 调节Treg在健康中的特性的TF之间的操作/对抗，以及微环境 像WNT这样的队列在疾病环境中利用它们。预期的发现有可能为小说提供信息 自身免疫和癌症的诊断和治疗工具。

ABSTRACT The plasticity and functional diversity of regulatory T cells (Tregs) is essential for the maintenance of healthy immunity but it is also exploited in disease. We have described a subset of Tregs that express high levels of β- catenin and promote inflammation. The frequency of these Tregs is increased in inflammatory bowel diseases (and mouse colitis), colon cancer (and mouse polyposis), as well as in multiple sclerosis (and mouse EAE). Expression of a dominant active β-catenin, or ablation of Tcf-1 in Tregs both foster expression of Rorγt the canonical transcription factor of the Th17 lineage, and promote a Th17 differentiation signature. In the mesenteric lymph nodes (MLN) of healthy mice, we identified at least 5 transcriptionally distinct activated clusters of Tregs. One of these clusters is defined by expression of Rorγt and has prominent Th17 differentiation characteristics. In Tcf-1 deficient Tregs the Th17 differentiation profile expanded to all other clusters, and the RORγt cluster increased in frequency. The Tcf-1 deficient Tregs in spite of being more Th17 like, suppressed T-cells, however they failed to suppress inflammation. This indicates a bifurcation of Treg suppressive functions and begs the question, of whether it involves a co-operation between TCF-1 and Foxp3. We have found that, TCF-1 and Foxp3 co-bind enhancer elements of genes involved in T cell activation and Th17 differentiation. β-catenin induces newly accessible chromatin regions at these enhancers and upregulates the expression of the associated genes. Moreover, the E-box binding protein HEB works together with TCF-1 and potentially also Foxp3 to regulate these genes, since Treg specific ablation of both TCF-1 and HEB (but not each one alone) rescues inflammatory and autoimmune pathologies associated with β-catenin activation in Tregs. Consistently, HEB regulates RORγt, represses Foxp3 and peripheral Treg development. Our findings are in line with the notion that FoxP3 directly activates or represses transcription, in a context- and partner-dependent manner. They further implicate β-catenin, TCF-1, and HEB in partnering with Foxp3 to independently regulate the diverse Treg suppressive activities. Based on these findings we hypothesize that, Wnt/β-catenin signaling differentially regulates Treg suppressive functions and diversity, by controlling access of Foxp3 and HEB to select chromatin sites bound by Tcf-1. To address this hypothesis in specific Aim 1 we will determine the role of β-catenin and Tcf-1 in preparing the epigenetic landscape for Foxp3 binding and in shaping Treg cell type diversity. In specific Aim 2 we will determine the role secreted Wnt ligands in defining the functional properties of colon infiltrating Tregs. The proposed studies will elucidate fundamental co- operations/antagonisms between TFs that regulate Treg properties in health, and how microenvironment queues like Wnts exploit them in disease settings. The expected findings have the potential to inform novel diagnostic and therapeutic tools for autoimmunity and cancer.