Amino acid sensing and phenotypic adaptation in T cells

T 细胞的氨基酸传感和表型适应

• 批准号: 8218799
• 负责人: PETER J. MURRAY
• 金额: $ 26.25万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8218799
• 关键词: Ablation; Adopted; Affect; Amino Acids; Anabolism; Antigen-Presenting Cells; Antigens; Arginine; Autoimmune Process; Autoimmunity; Behavior; Biochemical; Biological Availability; CD4 Positive T Lymphocytes; Cell Culture Techniques; Cell physiology; Cells; Characteristics; Chemicals; Cholesterol; Coupled; Data; Decision Making; Disease; Elements; Employee Strikes; Enzymes; Essential Amino Acids; Future; Genetic; Glycolysis; Granulomatous; Growth; Helper-Inducer T-Lymphocyte; Hepatocyte; Host Defense Mechanism; Hydrolase; Immune; Immune response; Immunity; Individual; Individuality; Infection; Knowledge; Link; Liver; Liver parenchyma; Maintenance; Mediating; Metabolic; Metabolic Control; Metabolic Pathway; Metabolism; Methods; Molecular Profiling; Mus; Nature; Outcome; Pathway interactions; Pharmaceutical Preparations; Phenotype; Population; Process; Proteins; Publications; Reaction; Regulation; Regulatory T-Lymphocyte; Relative (related person); Research; Resources; Role; Running; Schistosoma; Signal Pathway; Signal Transduction; Site; Starvation; Syndrome; System; T cell differentiation; T cell response; T-Cell Proliferation; T-Cell Receptor; T-Lymphocyte; Tryptophan; Whole Organism; Work; arginase; base; cell growth; cytokine; egg; fatty acid biosynthesis; genome-wide; human FRAP1 protein; in vivo; innovation; interest; macrophage; novel; prevent; research study; response; self reliance; urea cycle

DESCRIPTION (provided by applicant): Despite the resurgence in interest in basic metabolic control, a large gap in knowledge concerns cell and context specific alteration and adaptation in each key pathway including the mTOR and AMPK pathways. In this proposal we will investigate a new pathway that links amino acid sensing with downstream alterations in T cell metabolism that have profound effects on T cell phenotype and function. The availability of essential amino acids has emerged as a central metabolic mechanism that regulates both T cell growth and the eventual T cell differentiation state. Antigen-presenting cells (APCs) regulate amino acid bioavailability to T cells via expression of inducible enzymes that degrade essential amino acids such as arginine and tryptophan, and have been hypothesized to restrict T cell activity and proliferation in immune microenvironments. The metabolic consequence to the T cells exposed to an amino acid-depleted microenvironment, and the downstream effects on T cell differentiation are at present poorly understood. We have discovered that arginine depletion has a central role in T cell metabolism that is directly relevant to in vivo diseases dominated by Th2 responses. To dissect the interplay between amino acid-depleting antigen presenting cells (APCs) and T cells we built a system where the APC, T cell and culture conditions can be manipulated by genetics and drugs that affect key metabolic checkpoints. Our approach has allowed us to evaluate metabolism in primary T cells undergoing APC-mediated arginine restriction, and can be used generally to investigate the consequences to both the T cell and APC for any amino acid. Our preliminary data suggests that arginine sensing by T cells involves an unanticipated mechanism that runs parallel to mTOR signaling to selectively shut down cholesterol/fatty acid biosynthesis but simultaneously maintain glycolysis. In this proposal we will investigate two elements of T cell metabolism. In Aim 1 we will define the hierarchy of signaling pathways activated by arginine starvation that leads to maintenance of glycolysis but ablation of cholesterol/fatty acid biosynthesis. Using genome-wide expression profiling of arginine-starved T cells compared to their dividing counterparts, we have discovered that the major downstream pathway responsive to arginine starvation is a shutdown of cholesterol/fatty acid biosynthesis that is completely reversible by exogenous arginine replacement. We will use genetic, biochemical and chemical methods to explore how the mTOR and AMPK and related pathways convert information about arginine levels into downstream metabolic decision points. In Aim 2 we will determine the interplay between key metabolic checkpoints including mTOR and AMPK that leads to helper T cell phenotypic plasticity. We have discovered that arginine-starved T cells change their fate to adopt characteristics of both Tregs and Th17 T cells. We will use innovative genetic approaches to track the genetic fate of T cells focusing on Treg-like cells marked with Foxp3-gfp. We will separate distinct T cell populations within arginine starved cultures based on Foxp3 expression and use these cells to understand how T cells use metabolic check points to make decisions about their phenotype. PUBLIC HEALTH RELEVANCE: Excessive T cell responses are a hallmark and driver of numerous autoimmune syndromes and diseases associated with disregulated immune responses. Our study focuses of a pathway that controls T cell proliferation and phenotype via sensing of amino acid depletion in microenvironments. We have found that amino acid sensing leads to metabolic pathway-driven changes in T cell fate. As such, our studies have wide implications for understanding and treating autoimmune syndromes.

描述（由申请人提供）：尽管对基本代谢控制的兴趣兴起，但知识的较大差距涉及细胞和上下文特定的更改和适应，包括MTOR和AMPK途径。在此提案中，我们将研究一种将氨基酸传感与T细胞代谢的下游改变联系起来的新途径，这些变化对T细胞表型和功能具有深远影响。必需氨基酸的可用性已成为一种调节T细胞生长和最终T细胞分化状态的中央代谢机制。抗原呈递细胞（APC）通过表达诱导酶来调节氨基酸生物利用度，从而降低必需氨基酸和色氨酸等必需氨基酸，并被认为可以限制T细胞活性和免疫微环境中的T细胞活性和增殖。目前对暴露于氨基酸耗尽的微环境的T细胞的代谢后果以及对T细胞分化的下游影响目前的影响很少。我们发现，精氨酸的耗竭在T细胞代谢中具有核心作用，这与由Th2反应支配的体内疾病直接相关。为了剖析缺乏氨基酸的抗原呈递细胞（APC）和T细胞之间的相互作用，我们构建了一个系统，可以通过影响关键代谢检查点的遗传学和药物来操纵APC，T细胞和培养条件。我们的方法使我们能够评估接受APC介导的精氨酸限制的原代T细胞中的代谢，并且可以通常使用任何氨基酸的T细胞和APC的后果。我们的初步数据表明，T细胞的精氨酸感测涉及一种意外的机制，该机制与MTOR信号平行，以选择性地关闭胆固醇/脂肪酸的生物合成，但同时维持糖酵解。在此提案中，我们将研究T细胞代谢的两个元素。在AIM 1中，我们将定义通过精氨酸饥饿而激活的信号通路的层次结构，这会导致维持糖酵解，但消融胆固醇/脂肪酸生物合成。使用精氨酸含量的T细胞的全基因组表达分析与它们的分裂对应物相比，我们发现对精氨酸饥饿有反应的主要下游途径是胆固醇/脂肪酸生物合成的关闭，这完全可通过外源精氨酸替代而完全可逆。我们将使用遗传，生化和化学方法来探讨MTOR和AMPK和相关途径如何将有关精氨酸水平的信息转换为下游代谢决策点。在AIM 2中，我们将确定关键代谢检查点之间的相互作用，包括MTOR和AMPK，这会导致辅助T细胞表型可塑性。我们发现精氨酸饥饿的T细胞改变其命运，以采用Treg和Th17 T细胞的特征。我们将使用创新的遗传方法来跟踪以FOXP3-GFP标记的Treg样细胞的T细胞的遗传命运。我们将根据FOXP3表达分离精氨酸饥饿的培养物中的不同T细胞群体，并使用这些细胞来了解T细胞如何使用代谢检查点来决定其表型。 公共卫生相关性：过度的T细胞反应是许多自身免疫性综合症和疾病的标志和驱动力，与无调免疫反应有关。我们的研究集中于通过感应微环境中氨基酸消耗来控制T细胞增殖和表型的途径。我们发现氨基酸的传感会导致T细胞命运的代谢途径变化。因此，我们的研究对理解和治疗自身免疫性综合征具有广泛的影响。