Mechanisms Controlling the Development and Function of Intestinal Effector Treg cells

项目总结 肠道效应Treg细胞发育和功能的调控机制这个 一系列称为炎症性肠病(IBD)的疾病的发病机制具有以下特点 对肠道微生物区系成分的免疫失调。来自老鼠和人类的发现突出了一个关键的， 免疫调节细胞因子IL-10在维持肠道免疫稳态中的非多余作用。 我们的实验室已经证明，Foxp3+调节性T(Treg)细胞是体内IL-10的主要来源 肠道，其中许多细胞共同表达规范的“th17”转录因子，rort--尤其是 在大肠(LI)。然而，IL-10只由Treg细胞的一部分产生--被定义为‘效应器’(E)Treg 细胞。控制eTreg细胞发育的机制还不完全清楚。这样做的前提是 基于两个PI(Weaver，Hatton)的最新发现和它们之间的协同作用而建立的应用程序是 到目前为止，IL-2和肿瘤坏死因子超家族的信号通路之间的相互作用是一个中心 在肠道中调节eTreg细胞的发育和功能的作用。具体地说，我们已经确定 肿瘤坏死因子受体超家族信号转导对TNFSF15-TNFRSF25(TL1A-DR3)是肿瘤坏死因子受体超家族信号转导通路的重要组成部分。 “中央”(C)Treg细胞向eTreg细胞的转变，并认为这一途径在 通过多种机制校准IL-2驱动的Treg细胞程序控制。我们假设TL1a- DR3通路在调节IL-2受体(IL-2R)信号以调节大小和cTreg-R方面是非冗余的。 动态平衡和炎症状态下LI Treg细胞库的eTreg平衡。此外，我们假设 DR3通过多种机制改变IL-2R的输出，从而调节IL-10的形成。 生产eTreg细胞。我们认为eTreg细胞发育的一个主要驱动力是STAT3产量的增加 IL-2R，通过DR3的作用增强：(I)增加IL-2R的敏感性；和(Ii)降低pSTAT3 降解，从而改变IL-2诱导的STAT5/STAT3比率。最后，我们建议其他TNFRSF 在DR3表达下降后，成员参与eTreg细胞的维持。我们通过以下方式检验这一假设 互补但不相互依赖的AIMS，杠杆：产生稳定的、治愈结肠炎的新方法 在体外培养Treg细胞；在原代T细胞中有效地敲除基因的新方法；以及新的基因靶向 小鼠模型来定义控制这些信号通路在控制 IL10和eTreg程序的转录调控。成功完成这些目标将建立新的 内源性IL-10上调的生物学范式和新的治疗方法 增强eTreg细胞的分化和功能以治疗人IBD。

PROJECT SUMMARY Mechanisms Controlling the Development and Function of Intestinal Effector Treg Cells. The pathogenesis of a spectrum of disorders referred to as inflammatory bowel disease (IBD) is characterized by immune dysregulation to components of the enteric microbiota. Findings from mouse and man highlight a critical, non-redundant role for the immunoregulatory cytokine IL-10 in maintenance of intestinal immune homeostasis. Our labs have shown that Foxp3+ regulatory T (Treg) cells are, overwhelmingly, the major source of IL-10 in the intestines, where many of these cells co-express the canonical “Th17” transcription factor, RORt—particularly in large intestine (LI). However, IL-10 is only produced by a subset of Treg cells—defined as ‘effector’ (e)Treg cells. Mechanisms that control the development of eTreg cells are incompletely understood. The premise of this application, founded on recent discoveries from, and synergy between, the two PIs (Weaver, Hatton) is that heretofore unappreciated interplay between signaling pathways of the IL-2 and TNF superfamilies has a central role in regulating the development and function of eTreg cells in the intestines. Specifically, we have identified the TNF receptor superfamily signaling pair, TNFSF15-TNFRSF25 (TL1A-DR3), as an important amplifier of the transition of “central” (c)Treg cells into eTreg cells and propose that this pathway plays an important role in calibrating IL-2–driven control of the Treg cell program via multiple mechanisms. We hypothesize that the TL1A- DR3 pathway is non-redundant in its regulation of IL-2 receptor (IL-2R) signaling to modulate the size and cTreg– eTreg balance of the LI Treg cell pool both at homeostasis and under inflammatory conditions. Further, we posit that DR3 acts through multiple mechanisms to alter output of the IL-2R to regulate development of IL-10– producing eTreg cells. We propose that a major driver of eTreg cell development is increased STAT3 output of the IL-2R, which is enhanced by actions of DR3 to: (i) increase sensitivity of the IL-2R; and (ii) decrease pSTAT3 degradation, thereby altering the IL-2–induced STAT5/STAT3 ratio. Finally, we propose that other TNFRSF members contribute to eTreg cell maintenance after DR3 expression declines. We test this hypothesis through complementary, but not inter-dependent, Aims, leveraging: a novel method for generating stable, colitis-curing Treg cells ex vivo; new approaches for efficient gene knock-downs in primary T cells; and new gene-targeted mouse models to define mechanisms governing the convergence of these signaling pathways in controlling the transcriptional regulation of Il10 and the eTreg program. Successful completion of these Aims will establish new biological paradigms and inform novel therapeutic approaches by which endogenous IL-10 can be up-regulated and the differentiation and function of eTreg cells enhanced to treat human IBD.