Induction and maintenance of regulatory T cells

描述(由申请人提供)：调节性CD4T淋巴细胞(Treg)对维持自身耐受性至关重要。这是一个计划项目拨款申请，以确定将允许最有效的生成和/或稳定和体内功能的Treg的因素。已经确定了几种类型的Treg，其中特征最好的类型，包括表达转录因子Foxp3的亚群，以及产生IL-10的亚群，将在拟议的实验中进行研究。主要研究人员在附近有实验室，他们相互作用广泛。这个小组的成员拥有互补的专业知识领域，从基因转录研究到临床试验的建立。它们在感染和免疫介导性疾病的相关动物模型中发挥作用，如I型糖尿病、结肠炎和哮喘。在刘博士领导的项目1中，我们将研究E3泛素连接酶Cbl-b如何通过导致转录因子Foxo3a活性增加的途径来刺激Foxp3的诱导。Kronenberg博士的项目2将探索Treg失去Foxp3表达和抑制功能时发生的遗传和功能变化，并将分析肠道髓系细胞的功能，这些细胞提供Treg维持结肠炎小鼠所需的关键IL-10。在von Herrath博士和他的团队领导的项目3中，我们将探索病毒感染如何改变不同类型的Treg的功能，并确定抗原提呈细胞对病毒的先天反应如何介导对Treg的影响。在克罗夫特博士领导的项目4中，我们将研究Galectins-3和Galectins-9，这两个凝集素是肿瘤坏死因子家族受体4-1BB的新配体。我们将确定这种相互作用影响Foxp3表达诱导的机制。拟议的研究将得到一个行政核心和一个生物统计/生物信息学核心的支持，这两个核心还将协助对细胞因子进行多参数分析。所采用的方法将包括尖端基因技术以及重要免疫疾病的体内模型。这项研究的发现将有助于理解创建有效的基于Treg的免疫疗法来治疗自身免疫性和炎症性疾病的方法。 相关性：免疫系统可预防感染，但也可产生自身免疫性或炎症性疾病，如I型糖尿病和哮喘。调节性T细胞可以防止这种过度活跃的免疫反应，并有可能将这些细胞用作一种新的治疗方法。我们将使用尖端方法来更好地了解如何提高调节性T细胞预防自身免疫性疾病的能力。 项目1： 标题：蛋白质泛素化对Foxp3表达的转录调控 项目负责人：刘勇。 项目1描述(申请人提供)：我们的长期目标是研究正常和疾病条件下免疫反应的调节，特别是蛋白质泛素化途径在淋巴细胞发育、激活和耐受诱导中的作用。CBL-b由N-末端酪氨酸激酶结合区、一个环指和C-末端富含Pro的序列组成。对Cbl-b缺陷小鼠的遗传学研究表明，Cbl-b在T细胞激活中起着关键作用，Cbl-b的缺失会导致自身免疫力的增强。CBL-b作为环型E3泛素连接酶，促进泛素与关键信号分子的结合，影响其生物学功能。更重要的是，我们发现Cbl-b在T细胞无能诱导过程中上调，并控制耐受过程，从而将蛋白质泛素化途径与T细胞耐受联系起来。我们最近获得了一些意想不到的新奇观察结果。特别是，我们发现Cbl-b通过直接作用于Foxp3基因转录调控的一条新的信号通路参与了可诱导调节性T细胞(ITregs)中Foxp3表达的调控。这些新的发现为我们假设Cbl-b通过促进蛋白质泛素化在控制免疫反应中发挥重要作用奠定了坚实的基础。在这个提议中，我们计划：1)研究Cbl-b E3泛素连接酶通过调节Foxo3a基因转录来调节Foxp3基因转录的分子机制，并进行Tregs全基因组基因谱分析，以了解Tregs表观遗传控制的分子调控；2)在小鼠自身免疫和呼吸道炎症模型中检测iTregs的体内功能。这些研究将极大地促进我们对Foxp3基因转录和iTreg介导的免疫调节的分子机制的理解。这些知识最终将促进癌症、自身免疫和过敏性疾病的新治疗方法的设计。 相关性：免疫系统已经进化为对入侵的病原体做出强大的反应，但同时对自身组织或自身抗原具有耐受性。免疫耐受的调控机制尚不清楚。这项提议将研究免疫反应被适当控制的机制。这些知识最终将有助于设计免疫疾病的新治疗方法。

DESCRIPTION (provided by applicant): Regulatory CD4 T lymphocytes (Treg) are critical for the maintenance of self-tolerance. This is a Program Project grant application to identify the factors that will allow for the most efficient generation and/or stabilization and In vivo function of Treg. Several types of Treg have been identified, the best characterized ones, including subsets that express the transcription factor Foxp3, and ones that produce IL-10, will be studied in the proposed experiments. The principal investigators have laboratories In proximity and they interact extensively. The members of this group have complementary areas of expertise ranging from gene transcription studies to the set up of clinical trials. They work in relevant animal models of infection and immune mediated diseases such as type I diabetes, colitis and asthma. In Project 1, led by Dr. Liu, we will investigate how an E3 ubiquitin ligase, Cbl-b, stimulates Foxp3 induction, via a pathway that leads to increased activity of the transcription factor Foxo3a. Project 2, from Dr. Kronenberg, will explore the genetic and functional changes that occur when Treg lose Foxp3 expression and suppressive function, and will analyze the function of the intestinal myeloid cells that provide the critical IL-10 required for Treg maintenance in mice with colitis. In Project 3, led by Dr. von Herrath and his group, we will explore how the function of different types of Treg are altered by viral infections, and we will determine how the innate responses by antigen presenting cells to viruses mediate effects on Treg. In Project 4 led by Dr. Croft, we will examine the lectins Galectins-3 and -9, which we have shown are novel ligands for the TNF family receptor 4-1 BB. We will determine the mechanism whereby this interaction influences the induction of Foxp3 expression. The proposed research will be supported by an Administrative Core and a Biostatistics/Bioinformatics core that also will assist with the multi-parameter analysis of cytokines. Methods employed will include cutting edge genetic technologies as well as in vivo models of important immune diseases. The findings from this research will help in understanding the means for creating effective Treg-based Immune therapies for the treatment of autoimmune and inflammatory diseases. RELEVANCE: The immune system prevents infections, but can also create autoimmune or inflammatory diseases such as type I diabetes and asthma. Regulatory T cells prevent such over exuberant immune responses, and it may be possible to use these cells as a novel therapy. We will use cutting edge methods to provide a better understanding of the ways to improve the ability of regulatory T cells to prevent autoimmune disease. PROJECT 1: Title: Transcriptional Regulation of Foxp3 Expression by Protein Ubiquitination Project Leader: Liu, Y. PROJECT 1 DESCRIPTION (provided by applicant): Our long-term goal is to study the regulation of immune responses under normal and diseased conditions, particularly the invovlement of protein ubiquitination pathway in lymphocyte development, activation, and tolerance inductiion. Cbl-b is composed of an N-terminal tyrosine kinase binding domain, a RING finger, and C-terminal proline-rich sequences. Genetic studies using Cbl-b deficient mice have shown that Cbl-b is critical in T cell activation, and loss of Cbl-b results in increased autoimmunity. Cbl-b functions as RING-type E3 ubiquitin ligase to promote ubiquitin conjugation to critical signaling molelcules and affects their biological functions. More importantly, we showed that Cbl-b is upregulated during T cell anergy induction and controls the tolerigenic process, thus linking protein ubiquitination pathway to the T cell tolerance. We have recently obtained some unexpected and novel observations. Particularly, we found that Cbl-b is involved in the regulation of Foxp3 expression in inducible regulatory T cells (iTregs) via modulating a novel signaling pathway directly acting at the transcriptional regulation of Foxp3 gene. The new findings form a strong basis for us to hypothesize that Cbl-b plays an essential role in controlling immune responses via promoting protein ubiquitination. In this proposal, we wll plan: 1) to investigate the molecular mechanisms by which Cbl-b E3 ubiquitn ligase regulates Foxp3 gene transcription via modulating Foxo3a-directed gene transcription and to perform genome-wide gene profiling of Tregs to understand the molecular regulation of epigenetic control in Tregs; 2) to examine the in vivo function of iTregs in mouse models of autoimmunity and airway inflammation. These studies will significantly advance our understanding of the molecular mechanisms governing Foxp3 gene transcription and iTreg-mediated immune regulation. Such knowledge will eventually facilitate the design of novel therapeutic approaches for cancer, autoimmune and allergic diseases. RELEVANCE: The immune system has evolved to mount robust responses against invading pathogens, but at the same time is tolerant to self-tissues or self-antigens. The mechanisms governing immune tolerance are not clear. This proposal will study the mechanisms by which the immune responses are properly controlled. Such knowledge will eventually facilitate the design of novel therapeutic approaches for immunological diseases.