Transciptional Regulation of the Type 1 T Cell Response

描述：(申请人提供)：辅助性T细胞的调节 克隆性扩增和分化影响感染和 对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汇聚到转录因子上 确定辅助性T细胞的效应器反应。这项工作的长期目标 是为了刻画转录机制的特征，这些转录机制调控着 效应性T细胞在体内和体外的反应。效应性T细胞表达 细胞因子的限制性图谱，在极端情况下标记为T细胞 辅助性细胞1(Th1)或辅助性T细胞2(Th2)。当天真的，未承诺的T助手 前体细胞成为Th1效应器，产生肿瘤坏死因子和干扰素-γ，它们提供 有助于炎症和宿主对病原体的防御 吞噬细胞。由于这种在宿主防御中的关键作用，这些机制通过 哪些信号和转录调控通路控制Th1 体内发育是至关重要的。炎症性疾病的力量 效应器的反应必须不仅由特定的激活来确定 细胞因子基因(例如，干扰素-γ)也受到克隆扩增效率的影响 抗原特异性T细胞和分化后的基因转录速率。 使用T细胞特异的转基因模型来研究 在体内，我们发现了对核因子-kB的优先需求。 1型(炎症性)T细胞依赖反应与2型的比较 (过敏)反应。初步研究提供了克隆扩张的证据 在活体内是受损的，也是支持存在的特定要求 针对核因子-kB在干扰素-g基因激活中的作用。使用转基因T细胞和 逆转录病毒载体介导的转导，在目标1中，我们将区分 克隆性扩张对效应细胞因子基因激活的贡献，以及 确定核因子-kB在干扰素-γ基因激活中的作用机制(S)。在这 目的：一种假说是，核因子-kB优先促进克隆扩增 通过调节对重新刺激诱导的死亡的保护。一秒钟 假说认为，核因子-kB/Rel通路调节 Th1特异性转录因子T-bet，并与T-bet在 调节干扰素-伽马转录率。为配合这些研究，我们会 使用基因敲除小鼠来检验一个特定的核因子-kB亚单位，Rem， 在Th1发育中发挥T细胞的内在作用(目标2)。最后，在目标3中，我们 将研究T-bet和NF-kB/REL通路之间的相互作用 与干扰素-γ初始激活相关的表观遗传学改变 基因表达(染色质重组和CpG甲基化)。团结在一起， 拟议的实验将提供对转录的重要见解 调节T细胞依赖的炎症反应。

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.