NFAT in naive, effector and memory Th1 and Th2 cells

初始、效应Th 1和Th 2以及记忆性CD 4 + T细胞的平衡对于免疫应答过程至关重要。这些阶段的CD 4 + T细胞在细胞因子产生、活化信号需求、表面标记表达和寿命方面存在差异，但对决定这些表型特征的分子机制知之甚少。 该项目代表了一个努力，以确定的调节和作用的转录因子NFAT的幼稚，效应和记忆CD 4 + T细胞的分化和激活。我们前期的研究表明，特定转录因子的活性调节依赖于细胞的分化阶段。 我们已经表明，AP-1和NFAT可以介导效应Th 2细胞中的转录，但不能介导Th 1细胞中的转录。 AP-1和NFAT介导的转录需要T细胞受体（TcR）和幼稚CD 4 + T细胞中的共刺激信号，而效应Th 2细胞中仅需要TcR介导的信号。 AP-1复合物中JunB的存在似乎与Th 2细胞中AP-1转录活性的特异性调节有关。在这个项目中，我们建议扩展这些研究，以确定如何NFAT转录活性调节过程中的幼稚和效应CD 4+细胞的记忆细胞的发展，特别是基因表达，DNA结合，和核转位的不同NFAT家族成员（目的1）。 我们的初步数据表明，NFAT家族的两个组成部分，NFAT 1和NFAT 2的相对比例，在CD 4 + T细胞的分化过程中变化，这可能是一个NFAT介导的转录调节因子。 我们将通过在CD 4 + T细胞克隆中过表达NFAT 2来确定NFAT 1/NFAT 2比率的变化是否影响体外活化/死亡分子基因的细胞因子的表达（Aim 2）。 为了确定NFAT 1/NFAT 2比率对体内初始、效应和记忆CD 4 + T细胞的产生、活化和存活的生理相关性，我们将使用转基因小鼠以诱导方式在T细胞中选择性过表达NFAT 2（目的3）。 我们相信，这些研究将提供新的见解的重要性，NFAT的控制效应和记忆免疫反应。

The balance of naive, effector Th1 and Th2 and memory CD4+ T cells is critical for the course of an immune response. Differences in cytokine production, activation signal requirement, surface maker expression and life span characterize these stages of CD4+ T cells, but little is known about the molecular mechanisms that determine these phenotype characteristics. This project represents an effort to define the regulation and the role of the transcription factor NFAT in the differentiation and activation of naive, effector and memory CD4+ T cells. Our previous studies have demonstrated that the regulation of the activity of specific transcription factors depends on the differentiation stage of cells. We have shown that AP-1 and NFAT can mediate transcription in effector Th2 cells, but not in Th1 cells. AP-1- and NFAT-mediated transcription requires T cell receptor (TcR) and co-stimulatory signals in naive CD4+ T cells, while only TcR-mediated signals are required in effector Th2 cells. The presence of JunB in AP-1 complexes appears to be relevant for the specific regulation of AP-1 transcriptional activity in Th2 cells. In this project we propose to extend these studies to determine how NFAT transcriptional activity is regulated during the development of memory cells for naive and effector CD4+ cells, specifically gene expression, DNA binding, and nuclear translocation of the different NFAT family members (Aim 1). Our preliminary data suggest that the relative ratio of two components of the NFAT family, NFAT1 and NFAT2, varies during the differentiation of CD4+ T cells and that can be one regulatory factor of NFAT-mediated transcription. We will determine whether changes in the NFAT1/NFAT2 ratio influence the expression of cytokine of activation/death molecule gene in vitro, by overexpressing NFAT2 in CD4+ T cell clones (Aim 2). To determine the physiological relevance of NFAT1/NFAT2 ratio on the generation, activation and survival of naive, effector and memory CD4+ T cells in vivo, we will overexpress NFAT2 selectively in T cells in an inducible manner using transgenic mice (Aim 3). We believe that these studies will provide new insights about the importance of NFAT in the control of effector and memory immune responses.