Transciptional Regulation of the Type 1 T Cell Response

1 型 T 细胞反应的转录调控

• 批准号: 6323667
• 负责人: Mark R Boothby
• 金额: $ 33.75万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-30 至 2002-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6323667
• 关键词: gene induction /repression; genetic transcription; genetically modified animals; helper T lymphocyte; interferon gamma; laboratory mouse; lymphocyte proliferation; nuclear factor kappa beta

DESCRIPTION: (Provided by the Applicant): The regulation of helper T-cell clonal expansion, and differentiation influences the outcome of infections and the susceptibility to autoimmune diseases. Signal transduction pathways activated by cell surface receptors converge on transcriptional factors which determine effector responses by helper T-cells. A long-term goal of this work is to characterize transcriptional mechanisms that regulate the potency of effector T-cell responses in vivo as well as in vitro. Effector T-cells express restricted profiles of cytokines which in the extremes mark them as being T helper 1 (ThI) or T helper 2 (Th2) cells. When naive, uncommitted T helper precursors become Th1 effectors that produce TNFs and IFN-gamma, they provide help essential to inflammation and the host defense against pathogens in phagocytic cells. Because of this key role in host defense, the mechanisms by which signaling and transcriptional regulatory pathways control Th 1 development in vivo are of critical importance. The strength of an inflammatory effector response must be determined not only by the activation of specific cytokine genes (e.g., IFN-gamma) but also by efficiency of clonal expansion of antigen-specific T-cells and rates of gene transcription after differentiation. Using a T-cell-specific transgenic model to investigate the role of the NF-k/Rel pathway in vivo, we discovered a preferential requirement for NF-kB in the type 1 (inflammatory) T-cell-dependent response as compared to a type 2 (allergic) response. Preliminary studies provide evidence that clonal expansion in vivo is impaired, but also support the existence of a specific requirement for NF-kB in IFN-g gene activation. Using transgenic T-cells and retrovector-mediated transduction, in Aim 1 we will distinguish the relative contributions of clonal expansion vs. effector cytokine gene activation, and identify mechanism(s) of NF-kB in interferon gamma gene activation. In this Aim, one hypothesis is that NF-kB preferentially promotes Thi clonal expansion by mediating protection against restimulation-induced death. A second hypothesis is that the NF-kB/Rel pathway regulates induction of the Th1-specific transcription factor T-bet, and collaborates with T-bet in regulating IFN-gamma transcription rates. To complement these studies, we will use knockout mice to test the hypothesis that one specific NF-kB subunit, Rem, plays a T-cell-intrinsic role in Th1 development (Aim 2). Finally, in Aim 3 we will investigate the interplay between the T-bet and NF-kB/Rel pathways in effecting epigenetic changes associated with the initial activation of IFN-y gene expression (chromatin restructuring and CpG methylation). Together, the proposed experiments will provide important insights into the transcriptional regulation of T-cell-dependent inflammatory responses.

描述：（由申请人提供）：辅助性T细胞的调节 克隆扩张和分化影响感染的结果， 自身免疫性疾病的易感性信号转导途径 由细胞表面受体激活的转录因子聚集， 通过辅助性T细胞确定效应子应答。这项工作的长期目标是 是为了描述调控转录机制的能力， 体内和体外效应T细胞反应。效应T细胞表达 细胞因子的限制性特征，在极端情况下将其标记为T 辅助1（ThI）或辅助T 2（Th 2）细胞。当天真的，未定型的T辅助细胞 前体成为产生TNF和IFN-γ的Th 1效应物，它们提供 帮助炎症和宿主防御病原体至关重要， 吞噬细胞由于在宿主防御中的这一关键作用， 哪些信号和转录调节途径控制Th 1 在体内的发展是至关重要的。一种煽动性的力量 效应子应答不仅必须通过特异性的 细胞因子基因（例如，干扰素-γ），而且还取决于克隆扩增的效率 抗原特异性T细胞和分化后的基因转录速率。 使用T细胞特异性转基因模型来研究 在体内NF-k/Rel通路中，我们发现NF-kB的优先需求， 1型（炎症）T细胞依赖性反应与2型（炎症）T细胞依赖性反应相比， （过敏）反应。初步研究提供了克隆扩张 在体内受损，但也支持存在一个特定的要求， 在IFN-γ基因激活中NF-κ B的表达。使用转基因T细胞， 逆转录病毒载体介导的转导，在目标1中，我们将区分相对 克隆扩增相对于效应细胞因子基因活化的贡献，和 鉴定干扰素γ基因活化中NF-κ B机制。在这 目的，一种假设是NF-kB优先促进Thi克隆扩增， 通过介导对再刺激诱导的死亡的保护。第二 假设是NF-kB/Rel途径调节了 Th 1特异性转录因子T-bet，并与T-bet合作， 调节IFN-γ转录速率。为了补充这些研究，我们将 使用基因敲除小鼠来检验一个特定的NF-kB亚基，Rem， 在Th 1发育中起T细胞内在作用（Aim 2）。最后，在目标3中， 将研究T-bet和NF-kB/Rel通路之间的相互作用， 影响与IFN-γ初始活化相关的表观遗传变化 基因表达（染色质重组和CpG甲基化）。统称 提出的实验将提供重要的见解转录 调节T细胞依赖性炎症反应。