TRANSCRIPTIONAL REGULATION OF TH1/TH2 DIFFERENTIATION

TH1/TH2 分化的转录调控

• 批准号: 6164011
• 负责人: Thomas M. Aune
• 金额: $ 11.61万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-03-15 至 2002-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6164011
• 关键词: T cell receptor; T lymphocyte; antigen presenting cell; cell differentiation; cellular immunity; enzyme linked immunosorbent assay; flow cytometry; gene expression; genetic regulatory element; genetically modified animals; humoral immunity; immunologic memory; interferon gamma; interferons; interleukin 4; laboratory mouse; lymphocyte proliferation; southern blotting; systemic lupus erythematosus; transcription factor

Acquiring the ability to selectively produce interferon gamma (IFNgamma) or interleukin 4 (lL4) is a fundamental property of the immune system and enables T cell subsets (T helper 1, TH1, T helper 2, TH2) to deliver their effector functions. While the accumulated data clearly validate the polarization paradigm, the molecular mechanisms which control differentiation of naive T cells into memory TH1 or TH2 cells are not well understood. Much of what is known about regulation of gene transcription and the activity of individual response elements is derived from studies using immortalized cell lines. Very little is known about the regulation of transcriptional elements in primary cells nor about how transcriptional activity is regulated as primary cells differentiate or respond to external stimuli. This is largely due to the lack of an experimental system which permits investigation of promoter-directed transcriptional activity in primary cells. To address these questions, a novel experimental system will be employed. This system utilizes transgenic mice which express the luciferase gene under the control of a) proximal (prox. b-ZlP[IFNgamma]) and b) distal (dist. b-ZIP[IFNgamma]) response elements from the IFNgamma promoter, which bind b-ZIP transcription factors, c) the -538 to + 64 bp IFNgamma promoter, and d) a response element from the lL4 promoter which binds NF-AT/AP-1 transcription factors. The hypothesis to be tested is that acquisition of memory results from changes in transcriptional activity. The specific aims will focus on a) analyzing changes in transcriptional activity as naive T cells differentiate into effector T cells, b) determining how modulation of gene expression alters transcriptional activity, c) identifying transcription factors required for transcriptional activity, and d) determining if genetic regulation of cytokine production is reflected at the level of transcriptional activity. The long term goals of this project are to understand the molecular events which prevent naive T cells from producing IFNgamma and IL4 and which allow memory T cells to selectively produce these cytokines and to identify the genetic loci which control the development of TH1 or TH2 immunity. In a more general sense, these studies will examine changes in transcriptional activity as cells differentiate in a natural environment and acquire new properties. The immune-based pathology associated with many infectious diseases, including HIV infection, may result from overexpression of lL4 and the pathology associated with autoimmune diseases may result from overexpression of IFNgamma. Understanding regulation of cytokine gene expression may make it possible to correct overexpression of these genes and alleviate pathology associated with these diseases.

获得选择性产生干扰素γ（IFN γ）的能力 或白细胞介素4（IL 4）是免疫系统的基本特性， 使T细胞亚群（T辅助细胞1，TH 1，T辅助细胞2，TH 2）能够递送 其效应器功能。虽然积累的数据清楚地证实了 极化范式，控制的分子机制， 幼稚T细胞向记忆性TH 1或TH 2细胞的分化并不 很好理解。关于基因调控的大部分知识 转录和活性的个别反应元件是衍生 从永生化细胞系的研究中很少有人知道 原代细胞中转录元件的调节也不知道如何调节 转录活性随着原代细胞分化或 对外界刺激作出反应。这主要是由于缺乏一个 实验系统，允许研究启动子导向的 原代细胞中的转录活性。为了解决这些问题， 将采用新颖的实验系统。该系统利用 转基因小鼠，其在以下基因的控制下表达荧光素酶基因： a）近端（prox. b-ZIP [IFN γ]）和B）远端（dist. b-ZIP[IFN γ]） 来自IFN γ启动子的反应元件，其结合b-ZIP c）-538至+64 bp IFN γ启动子，和d） 来自IL 4启动子的结合NF-AT/AP-1的应答元件 转录因子有待检验的假设是， 记忆力的变化来自于转录活性的变化。具体 aims将侧重于a）分析转录活性的变化， 幼稚T细胞分化成效应T细胞，B）确定如何 基因表达的调节改变转录活性，c） 鉴定转录活性所需的转录因子， 和d）确定细胞因子产生的遗传调节是否 反映在转录活性水平上。长期目标 这个项目的目的是了解阻止 幼稚T细胞产生IFN γ和IL 4，并允许记忆T细胞 细胞选择性地产生这些细胞因子， 控制TH 1或TH 2免疫发展的基因座。以更 一般意义上，这些研究将检查转录的变化， 细胞在自然环境中分化并获得新的 特性.与许多感染性疾病相关的免疫病理学 包括HIV感染在内的疾病可能是由IL 4的过表达引起的， 与自身免疫性疾病相关的病理学可能是由于 IFN γ的过度表达。了解细胞因子基因的调控 表达可以纠正这些基因的过度表达 并减轻与这些疾病相关的病理。