The role of Runx1 in the regulation of T cell anergy

翻译后摘要：T细胞无反应性是一种程序化的细胞低反应性状态，防止传播的 对自身的免疫反应因此，无反应性是自我耐受性的关键组成部分。因此 T细胞中无反应性程序的发展和维持受到许多机制的严格控制， 细胞内和细胞外。由于无反应性在自我耐受中很重要，因此了解无反应性的机制是至关重要的。 调节无反应程序的启动和调节的复杂生物学。我们在野生型 (WT)转录因子Runx 1表达降低的小鼠与无反应性T细胞相关，定义为 细胞表面标志物CD 73和FR 4的共表达。此外，T细胞中Runx 1的条件性缺失 使用CD 4-Cre产生更高频率的共表达CD 73和FR 4的T细胞。这支持了 Runx 1抑制CD 4 + T细胞无反应性的发展。CD 4-Cre Runx 1 cKO小鼠具有 T细胞成熟受阻，外周淋巴器官中CD 4 + T细胞极少。绕过这个 成熟缺陷，并测试Runx 1在外周血CD 4 + T细胞中的作用，我们已经产生了一种新的1：1混合 使用雌激素受体（ER）-Cre Runx 1 cKO骨髓混合的骨髓嵌合体（BMC）系统 B6.SJL野生型（WT）骨髓。这通过删除外周血中的Runx 1绕过了成熟缺陷。 CD 4 + T细胞在它们已经完全成熟后以他莫昔芬诱导的方式表达。此外，一半 细胞是Runx 1-足够的，允许分析T细胞内在效应。在这个系统中，我们发现， Runx 1调节细胞内在的无反应性诱导，因为CD 73和CD 40的共表达频率增加， 外周CD 4 + T细胞中的FR 4仅见于ER-Cre Runx 1 cKO细胞而非B6.SJL WT细胞 来自同一只老鼠。拟议研究的目的1将确定关键基因靶点Runx 1 调节以控制CD 4 + T细胞无反应性。为了做到这一点，通过RNA测序鉴定的候选基因将被 在我们的新的ER-Cre系统中分析，并且它们在无反应性中的作用将被功能性地评估。令人惊讶的是， 他莫昔芬治疗的动物中的ER-Cre Runx 1 cKO和B6.SJL CD 4 + T细胞在治疗后不能增殖。 体外TCR刺激，这表明Runx 1调节控制耐受性的细胞外源性信号传导机制。 目的2将阐明无能Runx 1缺陷型CD 4 + T细胞耐受野生型CD 4 + T细胞的关键机制。 为了完成这一目标，我们将研究候选基因在野生型细胞中的作用。进一步调查 Runx 1在CD 4 + T细胞无反应性中的作用将为了解免疫系统如何启动和维持免疫系统提供帮助。 自我宽容

Abstract: T cell anergy is a programmed state of cellular hyporesponsiveness that prevents the propagation of an immune response to self. Thus, anergy is a critical component of self-tolerance. Consequently, the development and maintenance of the anergy program in T cells is tightly controlled by many mechanisms, both cell-intrinsic and cell-extrinsic. Since anergy is important in self-tolerance, it is critical to understand the complex biology that regulates the initiation and regulation of the anergy program. We have found in wild-type (WT) mice that lower expression of the transcription factor Runx1 is associated with anergic T cells, defined by co-expression of the cell-surface markers CD73 and FR4. Furthermore, conditional deletion of Runx1 in T cells using a CD4-Cre produces a higher frequency of T cells that co-express CD73 and FR4. This supports the hypothesis that Runx1 suppresses the development of anergy in CD4+ T cells. CD4-Cre Runx1 cKO mice have a block in T cell maturation and have very few CD4+ T cells in peripheral lymphoid organs. To bypass this maturation defect, and test the role of Runx1 in peripheral CD4+ T cells, we have generated a novel 1:1 mixed bone marrow chimera (BMC) system using Estrogen Receptor (ER)-Cre Runx1 cKO bone marrow mixed with B6.SJL Wild Type (WT) bone marrow. This bypasses the maturation defect by deleting Runx1 in peripheral CD4+ T cells in a tamoxifen inducible manner after they have completed maturation. Furthermore, half the cells are Runx1-sufficient allowing for analysis of T cell-intrinsic effects. In this system, we have found that Runx1 regulates the cell-intrinsic induction of anergy, as increased frequency of co-expression of CD73 and FR4 in peripheral CD4+ T cells is only seen in the ER-Cre Runx1 cKO cells and not the B6.SJL WT cells derived from the same mouse. Aim 1 of the proposed studies will determine critical gene targets Runx1 regulates to control CD4+ T cell anergy. To do this, candidate genes identified by RNA-sequencing will be analyzed in our novel ER-Cre system, and their role in anergy will functionally assessed. Surprisingly, both the ER-Cre Runx1 cKO and the B6.SJL CD4+ T cells in the tamoxifen treated animals fail to proliferate upon in vitro TCR stimulus, suggesting that Runx1 regulates a cell-extrinsic signaling mechanism controlling tolerance. Aim 2 will define key mechanisms anergic Runx1-deficient CD4+ T cells use to tolerize wild type CD4+ T cells. To complete this aim we will examine the role of candidate genes in wild type cells. Further investigation of the role of Runx1 in CD4+ T cell anergy will provide insight into how the immune system initiates and maintains self-tolerance.