Critical role of TCF-1 on the epigenetic identity of memory T cells

本研究的目的是研究转录因子TCF-1在决定表观遗传特性中的作用， 记忆性CD8 + T细胞我们的适应性免疫系统已经进化出一种独特的能力， 通过产生记忆T细胞，在再次感染时保护宿主。更好的 了解记忆T细胞分化对于开发限制T细胞反应的策略至关重要， 器官移植或增强慢性感染期间的T细胞反应。虽然众所周知， 转录因子TCF-1是记忆性CD8 + T细胞功能所必需的，通过这种机制， 蛋白质控制记忆T细胞的命运仍不清楚。最近，我们发现了一种机制， TCF-1控制T细胞的发育与其前所未有的创造染色质的能力有关 幼稚T细胞的可及性景观。我们发现TCF-1选择性地富集在基因组区域， 在开发的最早阶段就变得无障碍，并且需要这些 监管要素。在单细胞水平，TCF-1可以决定T细胞中染色质的协调开放。 此外，异位TCF-1可以直接清除非T细胞中的抑制性染色质标记，产生新的TCF-1。 开放染色质，诱导T细胞基因表达。虽然我们最近的数据确定了 TCF-1在T细胞发育过程中表观基因组上的表达，我们的发现也提出了另一个关键问题： TCF-1对记忆T细胞表观遗传特性的作用？我们假设TCF-1协同 与转录因子伴侣的关系定义了记忆T细胞的表观遗传学景观。我们新的初步数据 进一步表明体外T细胞活化后TCF-1表达可导致染色质可及性的增加 前记忆基因然而，目前还不清楚TCF-1在T细胞中的表达是否对感染有反应， 可以创造记忆T细胞的表观遗传特性。TCF-1的结构域需要靶向 染色质及其潜在的协同因子也仍然未知。TCF-1如何依赖于 需要定义与前记忆基因相关表观基因组。为了回答这些问题，我们将审问 TCF-1及其潜在配偶体对体外CD8 + T细胞染色质状态和可及性的影响。 使用最先进的工具，我们将生成TCF-1依赖的3D基因组组织的图谱， 定义表观基因组的变化如何与记忆基因相关。我们将进一步在体内翻译这些发现 利用单细胞表观基因组学、转录组学和流式细胞术测定。预期的结果是， 该提案详细了解了TCF-1与染色质之间的基本相互作用， 外周T细胞，可用于设计联合疗法，包括表观遗传编辑， 随意选择性地改变T细胞的命运。

The goal of this proposal is to study the role of transcription factor TCF-1 in determining the epigenetic identity of memory CD8+ T cells. Our adaptive immune system has evolved a unique capacity to remember a pathogen through the generation of memory T cells, which protect the host in the event of reinfection. A better understanding of memory T cell differentiation is crucial for developing strategies to limit T cell responses in organ transplantation or enhance T cell responses during chronic infections. Although it is known that the transcription factor TCF-1 is required for memory CD8+ T cell function, the mechanisms through which this protein controls memory T cell fate remain unclear. Recently, we discovered that a mechanism through which TCF-1 controls the development of T cells relates to its unprecedented ability to create the chromatin accessibility landscape of naïve T cells. We found that TCF-1 is selectively enriched at genomic regions that become accessible at the earliest stages of development and is required for the accessibility of these regulatory elements. At the single-cell level, TCF-1 can dictate a coordinate opening of chromatin in T cells. Moreover, ectopic TCF-1 can directly erase repressive chromatin marks in non-T cells, generating de novo open chromatin and inducing the expression of T cell genes. While our recent data determined the novel role of TCF-1 on the epigenome during T cell development, our findings also raised another critical question: what is the role of TCF-1 on the epigenetic identity of memory T cells? We hypothesize that TCF-1 in cooperation with transcription factor partners defines the epigenetic landscape of memory T cells. Our new preliminary data further indicate that TCF-1 expression post T cell activation in vitro can lead to gains in chromatin accessibility at pro-memory genes. However, it remains unclear if TCF-1 expression in T cells responding to an infection can create the epigenetic identity of memory T cells. The domains of TCF-1 required for targeting the chromatin and its potential cooperating factors also remain unknown. How TCF-1 dependent changes on the epigenome relate to pro-memory genes needs to be defined. To answer these questions, we will interrogate the effect of TCF-1 and its potential partners on the chromatin state and accessibility of CD8+ T cells in vitro. Using the state-of-the-art tools, we will generate the map of TCF-1 dependent 3D genome organization and define how changes on the epigenome relate to memory genes. We will further translate these findings in vivo exploiting single-cell epigenomic, transcriptomic, and flow cytometry assays. The expected outcome of this proposal is a detailed understanding of the fundamental interaction between TCF-1 and the chromatin in peripheral T cells which can be exploited to devise combination therapies including epigenetic editing to selectively alter T cell fate at will.