Gastrointestinal Cues Influence Metabolic Control of Regulatory T cell Function

项目摘要 人类炎症性肠病（IBD）的特征在于对治疗的反应不一致和持续的炎症反应。 病原性效应CD 4 + T细胞的活化暗示调节性T细胞（Treg）功能障碍;然而， 对潜在的机制知之甚少。因此，本提案的总体目标是 阐明胃肠道因素影响Treg代谢和功能的机制， 定义治疗IBD的药理学和过继性Treg疗法的治疗目标。首次采用 互补的方法，我们已经观察到一个明确的线粒体超微结构（形状，嵴结构， 以及与内质网[ER]的物理相互作用），其与Treg代谢状态相关。我们 现在正准备探索如何：i）线粒体超微结构及其相关的代谢状态在THEX 抑制实验性结肠炎的各种小鼠模型中的肠道炎症;和ii） 线粒体超微结构的调节和功能可以驱动人类IBD的发病机制， 与相关健康个体相比，IBD患者的外周血和固有层。我们 初步数据表明，抗炎转化生长因子β 1（TGF-β1）细胞因子是一种关键的 通过其相关的分子结构，在Tendon中启动了MERC，从而暗示了 在Treg介导的IBD抑制中完整的MERC和随后的丙酮酸氧化。在我们的初步调查中 模拟IBD胃肠道的促炎环境的实验， 促炎细胞因子损害MERC并扰乱葡萄糖代谢，导致过量脂肪酸 氧化作为一种补偿机制，与载体处理的TTRY（“促炎细胞因子- 诱导的代谢重编程”）。此外，我们还发现，促炎性酪氨酸诱导的 通过抑制糖原合成酶3 β（GSK 3 β）的活性， 使用一类目前正在临床试验中探索用于其他适应症的抑制剂。根据这些小说 通过这些观察，我们提出了TGF-β1介导的ER-α接触的中心假设 其对于细胞代谢稳态、Treg功能和IBD发病机制的抑制是必需的。的 以下独立的具体目标旨在测试三个综合假设。首先，我们将直接 检验TGF-β1介导MERC并因此介导Treg功能的假设。第二，我们将测试 假设TGF-β1增强线粒体丙酮酸氧化并因此增强Treg功能。第三、 我们将通过MERC验证促炎细胞因子在体内维持IBD发病机制的假设 抑制作用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 这个假设。这一建议在技术和概念上都具有创新性， 提出了Treg生物学中的新概念，并鉴定了用于治疗性优化Treg的新机制， 即结合药理学和基于Treg的疗法，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.