Control of dysfunctional Tregs

项目概要 排斥仍然是长期移植存活的主要障碍，我们渴望揭开其中的谜底。 阻碍同种异体移植物稳定存活的基本机制。在上一个资助期间，我们研究了 Treg 功能障碍的机制，并确定 BATF 和 BATF3 是 Foxp3 的有效抑制因子， 抑制 Foxp3 表达和 Treg 诱导。这些研究还导致了 DHX15 的发现 解旋酶是 Foxp3 Tregs 的关键调节因子，因为在 Tregs 中条件性删除 Dhx15 会导致 外周调节性T细胞的严重耗竭和致命的自身免疫性疾病。本质上，DHX15 是 RNA 解旋酶（一种 RNA 结合动力蛋白），传统上被认为参与 RNA 加工。其 在控制 Tregs 中的作用是出乎意料的，并且清楚地揭示了 Tregs 以前未知的新方面 与目前已知的机制不同，揭示这些机制是中心目标 的这项建议。 我们的工作假设是 DHX15 控制 Treg 的身份和/或外周位点的存活，并且它 缺乏会导致它们回复为 Teff 或死于细胞凋亡。我们推测 DHX15 也可能 在移植部位控制 Tregs，它们必须克服炎症环境才能发挥抑制作用 功能。我们提出了 3 个目标来检验本应用中的这一假设：第一个目标是检验是否 DHX15 通过充当 RNA 剪接因子、处理编码 Treg 的 mRNA 来控制 Treg 身份。 Foxp3或Foxp3控制Tregs中的特征分子，第二个目标是解决DHX15是否 通过调节 IL-2 信号复合物来控制 Tregs 的存活，使 Tregs 因细胞凋亡而死亡 第三个目的是检查 DHX15 是否对移植部位的 Tregs 特别重要 最需要它们来促进移植耐受的地方。总的来说，DHX15是第一个RNA解旋酶 迄今为止已确定的控制Tregs的基因、转基因模型以及尖端技术 我们开发的方法使我们处于独特的位置，可以从机制上剖析 DHX15 解旋酶在调节 Tregs 中发挥作用，这是基础 Treg 生物学和 Treg 中相当重要的一个领域。 为基础的疗法。

Project Summary Rejection remains a major hurdle to long lasting transplant survival and we aspire to uncover the fundamental mechanisms that hinder stable allograft survival. In the last funding period, we studied the mechanisms of Treg dysfunctions and identified BATF and BATF3 as potent repressors of Foxp3, suppressing Foxp3 expression and Treg induction. These studies also led to the discovery of the DHX15 helicase as a critical regulator of Foxp3+Tregs, as conditional deletion of Dhx15 in Tregs resulted in a profound depletion of Tregs in the periphery and lethal autoimmune diseases. In essence, DHX15 is an RNA helicase (an RNA binding motor protein) and traditionally thought to be involved in RNA processing. Its roles in the control of Tregs are unexpected and clearly reveal novel previously unknown aspects of Tregs that are different from currently known mechanisms, and uncovering those mechanisms is the central goal of this proposal. Our working hypothesis is that DHX15 controls Treg identity and/or survival at peripheral sites and that its deficiency results in either their reversion to Teff or die of apoptosis. We surmise that DHX15 may also control Tregs at the graft site, where they must overcome the inflammatory milieu to exert suppressive functions. We proposed 3 Aims to test this hypothesis in this application: the first Aim is to test whether DHX15 controls Treg identity by acting as an RNA splicing factor, processing mRNAs that encode the Foxp3 or Foxp3 controlled signature molecules in Tregs, the second Aim is to address whether DHX15 controls Tregs survival by regulating the IL-2 signaling complex, such that Tregs die of apoptosis in its absence, and the third Aim is to examine whether DHX15 is especially important for Tregs at graft sites where they are needed the most in promoting transplant tolerance. Overall, DHX15 is the first RNA helicase identified thus far that controls Tregs, and the genetically modified models as well as cutting-edge approaches we have developed put us in a unique position in dissecting mechanistically how the DHX15 helicase acts in regulating Tregs, an area of considerable importance in both basic Treg biology and Treg- based therapies.