Mechanisms underlying T helper suppression by regulatory T cells

调节性 T 细胞抑制 T 辅助细胞的机制

• 批准号: 7487619
• 负责人: Ayana Jordan
• 金额: $ 4.1万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-11 至 2010-06-10
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7487619
• 关键词: Antigen-Presenting Cells; Autoimmune Diseases; Autoimmunity; Behavior; Biological Assay; CD4 Positive T Lymphocytes; Calcium; Cell Communication; Cell Nucleus; Cell physiology; Cells; Coculture Techniques; Complex; Cytoplasm; Cytotoxic T-Lymphocytes; DNA; DNA Binding; Effector Cell; Electrophoretic Mobility Shift Assay; Epigenetic Process; Family member; Gene Expression; Genes; Goals; Helper-Inducer T-Lymphocyte; Histone Deacetylase Inhibitor; Histone Deacetylation; Histones; Homeostasis; IL2 gene; Immune Tolerance; Immune system; Immunofluorescence Immunologic; Inbred BALB C Mice; Interleukin-2; Interleukins; Jordan; Maintenance; Malignant Neoplasms; Mature T-Lymphocyte; Mediating; Membrane; Modification; Molecular; Mus; NF-AT; Pattern; Peripheral; Play; Population; Process; Promoter Regions; Proteins; Receptor Signaling; Recruitment Activity; Research; Resistance; Rest; Role; Signal Pathway; Signal Transduction; System; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; Th1 Cells; Therapeutic Uses; Thymus Gland; Transcription Factor AP-1; Transcriptional Activation; Transcriptional Regulation; Transgenic Organisms; Trichostatin A; anergy; autoreactive T cell; cell type; chromatin immunoprecipitation; chromatin remodeling; cytokine; human disease; member; novel; nuclear factors of activated T-cells; promoter; protein expression; transcription factor

DESCRIPTION (provided by applicant): The overall goal of this project is to elucidate the changes that occur within T helper (Th) cells when suppressed by regulatory T cells (Tregs) and identify the molecular mechanisms underlying Treg mediated inactivation of effector T cell functions. The specific aims of this project include (1) characterizing the role of Nuclear Factor of Activated T cells (NFAT) within suppressed T cells, identifying the molecular mechanisms of activation, transcriptional partners and the interaction with downstream targets; and (2) determining if Treg function is controlled by silencing of the interleukin (IL-)2 gene. To approach the first aim, immunofluorescence will reveal if NFAT is retained in the cytoplasm or translocated across the membrane, where it is active and can induce the expression of proteins known to suppress T cell activation. Electrophoretic mobility shift assays will be used to determine if active NFAT proteins can bind DNA in the nucleus of suppressed Th cells, in the absence of AP-1. Subsequently, chromatin immunoprecipitation (ChIP) will be performed on suppressed Th1 cells to determine if activation by NFAT involves direct recruitment of this protein to the promoter regions of T cell inactivating genes. By completing our goals in aim one we intend to uncover the transcriptional regulation of NFAT activation within suppressed T cells and elucidate gene expression patterns that are necessary for the induction and maintenance of the unresponsive state. For the second aim, chromatin immunoprecipitation assays will determine if epigenetic modifications regulate IL-2expression in stimulated Tregs and suppressed Th cells. To study the role of histone deacetylation in the suppressor activity and function of Tregs, isolated Tregs from BALB/c mice will be cocultured with TCR transgenic D011.10 mice and stimulated in the presence or absence of the histone deacetylase inhibitor, Trichostatin-A. Our overall goal in aim two is to determine the role that chromatin remodeling plays in the induction of T cell tolerance and investigate the mechanisms that regulate cytokine expression in Tregs and in Treg-mediated suppression of Th cells. A clear understanding of how theIL-2 locus is regulated in both Tregs and suppressed cells will prove invaluable in elucidating Treg behavior and function. By uncovering the mechanisms of Treg-mediated suppression of effector T cell function, novel therapies inducing immune tolerance can be developed against a host of autoimmune diseases and cancers. This project is relevant to the public at large because of the importance this cell (Treg) plays in maintaining a healthy immune system. By studying the behavior of this cell type (Treg), the causes of different human diseases can be better understood and new therapies developed.

描述（由申请人提供）：该项目的总体目标是阐明辅助性 T 细胞（Th）在被调节性 T 细胞（Treg）抑制时发生的变化，并确定 Treg 介导的效应 T 细胞功能失活的分子机制。该项目的具体目标包括（1）表征激活T细胞核因子（NFAT）在抑制T细胞中的作用，确定激活的分子机制、转录伙伴以及与下游靶标的相互作用； (2) 确定 Treg 功能是否受白细胞介素 (IL-)2 基因沉默的控制。为了实现第一个目标，免疫荧光将揭示 NFAT 是否保留在细胞质中或跨膜转运，在细胞质中它是活跃的，并且可以诱导已知抑制 T 细胞激活的蛋白质的表达。电泳迁移率变动测定将用于确定在没有 AP-1 的情况下，活性 NFAT 蛋白是否可以结合受抑制的 Th 细胞核中的 DNA。随后，将对受抑制的 Th1 细胞进行染色质免疫沉淀 (ChIP)，以确定 NFAT 的激活是否涉及将该蛋白直接募集至 T 细胞失活基因的启动子区域。通过完成目标一，我们打算揭示受抑制的 T 细胞内 NFAT 激活的转录调控，并阐明诱导和维持无反应状态所必需的基因表达模式。对于第二个目标，染色质免疫沉淀分析将确定表观遗传修饰是否调节受刺激的 Tregs 和受抑制的 Th 细胞中的 IL-2 表达。为了研究组蛋白脱乙酰化在 Tregs 抑制活性和功能中的作用，将来自 BALB/c 小鼠的分离 Tregs 与 TCR 转基因 D011.10 小鼠共培养，并在组蛋白脱乙酰酶抑制剂 Trichostatin-A 存在或不存在的情况下进行刺激。我们第二个目标的总体目标是确定染色质重塑在诱导 T 细胞耐受中所起的作用，并研究调节 Tregs 中细胞因子表达和 Treg 介导的 Th 细胞抑制的机制。清楚地了解 IL-2 基因座在 Tregs 和抑制细胞中如何受到调节对于阐明 Treg 行为和功能将具有无价的价值。通过揭示 Treg 介导的效应 T 细胞功能抑制机制，可以开发出针对多种自身免疫性疾病和癌症的诱导免疫耐受的新疗法。该项目与广大公众相关，因为这种细胞 (Treg) 在维持健康的免疫系统方面发挥着重要作用。通过研究这种细胞类型 (Treg) 的行为，可以更好地了解不同人类疾病的原因并开发新的疗法。