Gastrointestinal Cues Influence Metabolic Control of Regulatory T cell Function

项目摘要 人类炎症性肠病(IBD)的特点是对治疗反应不一致和持续 致病效应分子CD4+T细胞的激活意味着调节性T细胞(Treg)功能障碍；然而， 人们对潜在的机制知之甚少。因此，这项建议的总体目标是 阐明胃肠道信号影响Treg代谢和功能的机制 确定治疗IBD的药物和过继Treg疗法的治疗目标。第一次使用 在补充方法中，我们观察到了明确的线粒体超微结构(形状，脊结构， 以及与内质网[ER]的物理相互作用)，与Treg代谢状态相关。我们 现在准备研究如何：i)特瑞格的线粒体超微结构及其相关的代谢状态 抑制各种实验性结肠炎小鼠模型的肠道炎症；以及ii)在 线粒体超微结构的调节和功能在人类IBD发病机制中的作用 IBD患者外周血和固有层与相关健康人的比较。我们的 初步数据表明，抗炎转化生长因子β1(转化生长因子-β1)细胞因子是一个关键的 Tregs中线粒体-内质网接触(Merc)的驱动因素通过其相关的分子结构，从而暗示 完整的Merc和随后的丙酮酸氧化在Treg介导的IBD抑制中的作用。在我们的预赛中 模拟IBD胃肠道促炎环境的实验，治疗Tregs 促炎细胞因子损害肾小球系膜细胞，扰乱糖代谢，导致过量脂肪酸 氧化作为一种代偿机制与赋形剂处理的Tregs(促炎症细胞因子- 诱导代谢重编程“)。此外，我们发现促炎细胞因子诱导 抑制糖原合成酶3β(Gsk3β)的活性逆转Treg的代谢重编程 在其他适应症的临床试验中使用一类目前正在探索的抑制剂。基于这些小说 观察到，我们提出了中心假设，即转化生长因子-β1介导线粒体-内质网接触 这对于细胞代谢动态平衡、Treg功能和抑制IBD的发病是必不可少的。这个 以下独立的具体目标被设计来检验三个整合的假设。首先，我们将直接 验证转化生长因子-β-1介导MERC，从而发挥Treg功能的假设。第二，我们将测试 假设转化生长因子-β1增强线粒体丙酮酸氧化，从而增强Treg功能。第三, 我们将验证促炎症细胞因子通过Merc在体内维持IBD发病机制的假说。 抑制力。我们建议利用与健康和IBD病理生理学相关的复杂方法来测试 这个假说。这一建议在技术和概念上都是创新的，也具有重要意义，因为它 提出了Treg生物学中的一个新概念，并确定了治疗优化Treg的新机制， 即结合药理学和基于Treg的治疗，以阻止IBD的难治性。

PROJECT ABSTRACT Human inflammatory bowel disease (IBD) is characterized by inconsistent response to therapies and persistent activation of pathogenic effector CD4+ T cells implying regulatory T cell (Treg) dysfunction; however, the underlying mechanisms are poorly understood. Therefore, the OVERALL OBJECTIVE of this proposal is to elucidate the mechanisms by which gastrointestinal cues impact Treg metabolism and function with the therapeutic goal of defining pharmacological and adoptive Treg therapies to treat IBD. For the first time using complementary approaches, we have observed a defined mitochondrial ultrastructure (shape, cristae structure, and physical interaction with the endoplasmic reticulum [ER]) which correlated with Treg metabolic state. We are now poised to exploit how: i) mitochondrial ultrastructure and its associated metabolic state in Tregs suppress gut inflammation in various mouse models of experimental colitis; and ii) a breakdown in the regulation and function of mitochondrial ultrastructure can drive human IBD pathogenesis by analyzing Tregs from peripheral blood and lamina propria of IBD patients compared to relevant healthy individuals. Our preliminary data suggest that anti-inflammatory transforming growth factor beta 1 (TGF-β1) cytokine is a critical driver of mitochondria-ER contact (MERC) in Tregs via its associated molecular architecture, thus implicating intact MERC and subsequent pyruvate oxidation in Treg-mediated suppression of IBD. In our preliminary experimentations mimicking the proinflammatory milieu of IBD gastrointestinal tract, treatment of Tregs with proinflammatory cytokines impaired MERC and perturbed glucose metabolism, leading to excessive fatty acid oxidation as a compensatory mechanism in contrast to vehicle-treated Tregs (“proinflammatory cytokine- induced metabolic reprogramming”). Furthermore, we discovered that proinflammatory cytokine-induced metabolic reprogramming of Tregs was reversed by inhibiting the activity of glycogen synthase 3 beta (GSK3β) using a class of inhibitors currently being explored in clinical trials for other indications. Based on these novel observations, we formulated the CENTRAL HYPOTHESIS that TGF-β1 mediates mitochondria-ER contact that is essential for cellular metabolic homeostasis, Treg function, and suppression of IBD pathogenesis. The following independent SPECIFIC AIMS are designed to test three integrated hypotheses. First, we will directly test the hypothesis that TGF-β1 mediates MERC and consequently Treg function. Second, we will test the hypothesis that TGF-β1 potentiates mitochondrial pyruvate oxidation and consequently Treg function. Third, we will test the hypothesis that proinflammatory cytokines perpetuate IBD pathogenesis in vivo via MERC inhibition. We propose to utilize sophisticated approaches relevant to health and IBD pathophysiology to test this hypothesis. This proposal, which is technically and conceptually innovative, is also significant because it presents a novel concept in Treg biology and identifies new mechanisms for therapeutically optimizing Tregs, namely combining pharmacological and Treg-based therapies, to halt the refractory nature of IBD.