Regulating peripheral T cell tolerance

描述（由申请人提供）：健康个体中的大多数T细胞处于初始静息或静止状态。静止通过防止不受控制的多克隆扩增来确保在限定的空间中维持大量T细胞库。最近的证据表明，T细胞的静止是积极编程和维持。然而，控制T细胞静止的机制知之甚少。稳态幼稚CD 8 T细胞的维持依赖于来自IL-7受体和T细胞抗原受体（TCR）的协调信号传导。TCR信号传导在TCR与负载有自身肽的主要组织相容性复合体I分子接合后启动。这种紧张性TCR信号传导是如何被严格控制以防止完全T细胞活化的，目前还知之甚少。二酰基甘油激酶（DGK）是将二酰基甘油（DAG）转化为磷脂酸（PA）的酶，磷脂酸是参与激活多种信号传导途径并调节多种细胞过程和功能的重要第二信使。在哺乳动物中，存在十种DGK异构体，但它们的生理功能知之甚少。我们发现，缺乏DGKα和γ-D，T细胞中表达的主要亚型，导致幼稚T细胞失去静止，导致获得效应功能。此外，DGKα和β 2-D双缺陷小鼠发生严重的自身免疫性疾病，其中T细胞起关键作用。本申请的目的是使用条件性DGKα和GFP-DGK β缺陷小鼠作为模型研究控制CD 8 T细胞静止的机制，并使用条件性表达WT和突变型GFP-DGK β融合蛋白的新生成小鼠对原代T细胞中的DGK β进行彻底的结构/功能分析。我们将检验以下假设：DGKα和β 1调节包括mTOR信号传导在内的多种信号传导途径，以确保T细胞耐受性和静止，以及DGK β 1通过不同的结构域/基序指导其定位和相互作用，使其能够在多个亚细胞区室中作为T细胞中的关键调节因子发挥作用。我们将追求以下两个具体目标。在目标1中，我们将研究由DGKα和CD 8 α控制以确保CD 8 T细胞静止的机制。在目标2中，我们将确定DGK β作为T细胞发育和耐受性的关键调节因子发挥作用的关键结构特征。本申请中提出的研究将为T细胞发育的信号转导控制提供新的见解， 静止以及DGK激酶如何在T细胞中发挥其关键的调节作用。

DESCRIPTION (provided by applicant): Most T cells in healthy individuals are in a naïve resting or quiescent state. Quiescence ensures the maintenance of the vast repertoire of T cells in a defined space by preventing uncontrolled polyclonal expansion. Recent evidence indicates that T cell quiescence is actively programmed and maintained. However, the mechanisms that control T cell quiescence are poorly understood. The maintenance of steady-state naïve CD8 T cells relies on orchestrated signaling from the IL-7 receptor and the T cell antigen receptor (TCR). TCR signaling is initiated after the engagement of the TCR with major histocompatibility complex I molecules loaded with self-peptides. How such tonic TCR signaling is tightly controlled to prevent full T cell activation is poorly understood. Diacylglycerol kinases (DGKs) are enzymes that convert diacylglycerol (DAG) to phosphatidic acid (PA), both important second messengers involved in activating in multiple signaling pathways and regulate diverse cellular processes and functions. In mammals, ten DGK isoforms exist yet their physiological functions are poorly understood. We have found that deficiency of both DGKα and ζ, the major isoforms expressed in T cells, causes na�ve T cells to lose quiescence, leading to acquisition of effector function. Furthermore, DGKα and ζ double deficient mice develop severe autoimmune diseases with T cells play critical roles. The objectives of this application are to investigate mechanisms that control CD8 T cell quiescence using conditional DGKα and ζ deficient mice as a model and to perform thorough structure/function analysis of DGKζ in primary T cells using newly generated mice that conditionally express WT and mutant GFP-DGKζ fusion proteins. We will test the hypotheses that DGKα and ζ modulate multiple signaling pathways including mTOR signaling to ensure T cell tolerance and quiescence and that DGKζ directs its localizations and interactions via distinct structural domains/motifs, enabling it to function in multiple subcellular compartments as a critical regulator in T cells. We will pursue the following two specific aims. In Aim 1, we will investigate mechanisms that are controlled by DGKα and ζ to ensure CD8 T cell quiescence. In Aim 2, we will determine structural features critical for DGKζ to function as a critical regulator for T cell development and tolerance. Studies proposed in this application will provide novel insight into the signaling control of T cell development and quiescence and how DGKζ fulfills its critical regulatory roles in T cells.