Distinct functions of E protein family members in regulating γδ T lineage commitment and effector fate

项目总结/摘要 属于gd谱系的T细胞已被证明在免疫系统中发挥独特和关键的作用。 gd T细胞广泛分布于粘膜和上皮细胞丰富的组织中，是重要的早期免疫调节细胞。 IL-17的来源，其将粒细胞募集到炎症部位以响应病原体。然而，在这方面， gd T细胞产生IL-17的失调也与多种病理状况有关， 自身免疫性疾病和癌症进展。与传统的ab T细胞不同，gd T细胞可以获得 在抗原暴露之前，在发育过程中在胸腺内快速产生炎性细胞因子。的 指定并将gd T细胞分配给IL-17（gdT 17）或干扰素-g（IFNg; gdT 1）的分子和细胞事件 发育过程中的效应物命运仍有待充分阐明。最近的证据表明，E蛋白，在 特别是高灵，是这种命运选择的关键媒介。HEB转录因子由Tcf 12编码， 基因位点，产生两种蛋白质，HEBAlt和HEBCan，它们的结构，转录 起始位点和表达模式。HEBAlt和HEBCan在部分重叠的时间表达， gd T细胞发育，但它们各自在gd T细胞前体的功能编程中的作用尚不清楚。 我们和其他人已经确定了许多有助于gd T细胞效应子命运获得的信号通路， 包括通过T细胞受体（TCR）、Notch和细胞因子受体起作用的那些。我们的目标是 了解HEB活性如何与gd T细胞编程的其他决定因素整合。鉴于我们最近 我们发现HEB因子是gdT 17细胞发育所必需的，而不是gdT 1细胞，我们推测， gd T细胞的最终分化和效应子功能编程由特异性HEB的相互作用指导 和具有TCR、Notch和细胞因子受体信号传导下游的转录调节因子的E2 A蛋白。我们 将利用一种新的体外模型系统，该系统指导gdT 1和gdT 17命运之间的命运分叉， 以及新的小鼠模型，我们已经产生，以阐明E蛋白二聚体的作用， HEBAlt、HEBCan和/或E2 A在确定gd T细胞效应子功能中的作用，并深入了解其分子机制。 通过组装全球基因调控网络，为这些事件奠定基础。我们的目标是：（1）确定 HEBAlt、HEBCan和E2 A在胸腺内gd T细胞分化中的作用 WT和突变小鼠中的结合伴侣;以及，2）评估HEB因子及其靶点在 人gd T细胞发育。我们的建议是建立在从所有计划项目中得出的关键观察结果的基础上。 拟议的实验将继续在TCR信号传导领域汲取互补的专业知识 （项目1）、小鼠遗传学（项目2）和染色质重塑（项目4）。我们的具体目标不仅会导致 更好地理解GD分化的机制，而且还提供了对以下作用的独特见解： 特异性E蛋白在T细胞发育和功能中的作用总之，我们的联合实验方法和 如果没有本计划所有成员的综合专门知识，概念整合是不可能的。

PROJECT SUMMARY/ABSTRACT T cells belonging to the gd-lineage have been shown to serve unique and critical roles within the immune system. gd T cells are widely distributed throughout mucosal and epithelial cell-rich tissues and are an important early source of IL-17, which recruits granulocytes to sites of inflammation in response to pathogens. However, dysregulation of IL-17 production by gd T cells has also been linked to multiple pathological conditions including autoimmune disease and cancer progression. Unlike conventional ab T cells, gd T cells can acquire the ability to rapidly produce inflammatory cytokines within the thymus during development, prior to antigen exposure. The molecular and cellular events that specify and assign gd T cells to the IL-17 (gdT17) or interferon-g (IFNg; gdT1) effector fates during development remain to be fully elucidated. Recent evidence indicates that E proteins, in particular HEB, are critical mediators of this fate choice. HEB transcription factors are encoded by the Tcf12 gene locus, which gives rise to two proteins, HEBAlt and HEBCan, that differ in their structure, transcription initiation sites, and expression patterns. HEBAlt and HEBCan are expressed at partially overlapping times during gd T cell development, but their respective roles in functional programming of gd T cell precursors are unclear. We and others have identified a number of signaling pathways that contribute to gd T cell effector fate acquisition, including those that operate through T cell receptor (TCR), Notch, and cytokine receptors. It is our goal to understand how HEB activity is integrated with other determinants of gd T cell programming. Given our recent finding that HEB factors are required for the development of gdT17, but not gdT1 cells, we hypothesize that the final differentiation and effector function programming of gd T cells is directed by the interplay of specific HEB and E2A proteins with transcriptional regulators downstream of TCR, Notch, and cytokine receptor signaling. We will take advantage of a new in vitro model system that directs fate bifurcation between the gdT1 and gdT17 fates, as well as novel mouse models that we have generated, to elucidate the roles for E protein dimers containing HEBAlt, HEBCan, and/or E2A in determining gd T cell effector function, and to gain insight into the molecular basis for these events by assembling global gene regulatory networks. Our aims are: 1) to define the roles of HEBAlt, HEBCan, and E2A in intrathymic gd T cell differentiation by identifying specific target genes and binding partners in WT and mutant mice; and, 2) to evaluate the roles of HEB factors and their targets in human gd T cell development. Our proposal is built upon key observations derived from all Program Projects. The proposed experiments will continue to draw the complementary expertise in the areas of TCR signaling (Proj.1), mouse genetics (Proj.2), and chromatin remodeling (Proj.4). Our specific aims will not only lead to a better understanding of the mechanism of gd differentiation but also provide unique insights into the roles of specific E proteins in T cell development and function. Taken together, our joint experimental approaches and conceptual integration would not be possible without the combined expertise of all members of this Program.