Distinct pathways for MR1 antigen presentation upon infection with intracellular versus extracellular pathogens

细胞内和细胞外病原体感染时 MR1 抗原呈递的不同途径

• 批准号: 9883714
• 负责人: Melanie J Harriff
• 金额: $ 37.07万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9883714
• 关键词: Antigen Presentation; Antigens; Bacteria; Bacterial Infections; Biological; Biological Assay; CD8-Positive T-Lymphocytes; Cell physiology; Cell surface; Cells; Containment; Critical Pathways; Data; Development; Early Diagnosis; Endoplasmic Reticulum; Environment; Epithelial Cells; Flow Cytometry; Fluorescence Microscopy; Human; Immunologics; Infection; Interferons; Libraries; Ligands; Lung; MHC Class I Genes; MHC Class II Genes; Measures; Metabolic Pathway; Monomeric GTP-Binding Proteins; Mucous Membrane; Mycobacterium tuberculosis; Pathway interactions; Play; Positioning Attribute; Prevalence; Prevention; Production; Proteins; Recycling; Regulation; Role; Sampling; Small Interfering RNA; Staphylococcus aureus; Streptococcus pneumoniae; T-Cell Activation; T-Lymphocyte; T-Lymphocyte Subsets; Tissues; Vaccine Design; Vitamin B Complex; airway epithelium; cell type; effector T cell; enzyme linked immunospot assay; extracellular; genetic approach; inflammatory milieu; novel therapeutics; novel vaccines; pathogen; prevent; response; small molecule; syntaxin 18; therapeutic target; trafficking

Project Summary Effector CD8+ T cells restricted by the non-classical Class I-like molecule MR1 (MAIT cells) are a conserved T cell subset prevalent in humans. Because CD8+ T cells recognize and destroy target cells infected with pathogens, lung-resident subsets like MAIT cells may be important for early containment of bacterial infections of the airway. In fact, we find that MAIT cells are highly enriched in the airways, positioning them to rapidly respond to bacterially infected airway epithelial cells (AEC). MAIT cells recognize small molecule ligands generated by bacterial metabolic pathways that are presented on MR1 by many cell types, including AEC. The prevalence of MAIT cells in mucosal tissues, the ubiquitous expression of MR1, and the presumed abundance of small molecule ligands suggest that MR1 is tightly regulated to prevent inappropriate MAIT cell activation. Interestingly, we found that AEC can present antigen from both intracellular and extracellular pathogens to MAIT cells. Furthermore, we demonstrate that ligands from intracellular infection are presented on MR1 by different pathways than those generated from extracellular pathogens. For this application, we present evidence that presentation of MR1 ligands from intracellular pathogens involves endosomal recycling and requires proteins that regulate endosomal trafficking like Rab6. In contrast, presentation of exogenously added ligands occurs through Rab6-independent mechanisms. This proposal is thus focused on defining distinct mechanisms for MR1 antigen presentation upon infection with intracellular versus extracellular lung pathogens. Defining distinct mechanisms for presentation of these ligands may be key to understanding how MAIT cells sample the airway environment and become activated. This project contains two Aims: Specific Aim 1. Define how Rab6 regulates presentation of MR1 ligands derived from the intracellular lung pathogen M. tuberculosis. We will determine how Rab6 regulates expression or localization of MR1 in human AEC. Additionally, we will determine the role of Rab6 in regulating the maturation of the Mtb endosomal compartment in human AEC. Specific Aim 2. Identify and validate Rab6-independent mechanisms for presentation of MR1 ligands from the extracellular lung pathogens Streptococcus pneumoniae and Staphylococcus aureus. We will identify trafficking molecules in AEC that are critical to presentation of ligands from extracellular pathogens and determine how these molecules impact bacterial infection and cellular localization of MR1.

项目概要 受非经典 I 类分子 MR1 限制的效应 CD8+ T 细胞（MAIT 细胞）是一种保守的 T 细胞 人类中普遍存在的细胞亚群。因为 CD8+ T 细胞识别并破坏感染的靶细胞 病原体、MAIT细胞等肺部驻留子集可能对于早期遏制细菌感染很重要 气道的。事实上，我们发现 MAIT 细胞在气道中高度富集，使它们能够快速 对细菌感染的气道上皮细胞（AEC）做出反应。 MAIT细胞识别小分子配体 由许多细胞类型（包括 AEC）在 MR1 上呈递的细菌代谢途径产生。这 粘膜组织中 MAIT 细胞的普遍性、MR1 的普遍表达以及推测的丰度 小分子配体的研究表明 MR1 受到严格调节以防止不适当的 MAIT 细胞激活。 有趣的是，我们发现 AEC 可以将细胞内和细胞外病原体的抗原呈递给 MAIT 细胞。此外，我们证明细胞内感染的配体通过以下方式呈递在 MR1 上： 与细胞外病原体产生的途径不同。对于此应用程序，我们提出 有证据表明来自细胞内病原体的 MR1 配体的呈递涉及内体回收和 需要调节内体运输的蛋白质，如 Rab6。相反，外源添加的呈现 配体通过不依赖 Rab6 的机制发生。因此，该提案的重点是定义不同的 细胞内与细胞外肺部病原体感染时 MR1 抗原呈递的机制。 定义这些配体呈递的不同机制可能是理解 MAIT 细胞如何表达的关键 对气道环境进行采样并被激活。 该项目包含两个目标： 具体目标 1. 定义 Rab6 如何调节源自细胞内肺的 MR1 配体的呈递 病原体结核分枝杆菌。我们将确定 Rab6 如何调节人类中 MR1 的表达或定位 建筑工程委员会。此外，我们将确定 Rab6 在调节 Mtb 内体成熟中的作用 人类 AEC 中的隔室。 具体目标 2. 识别并验证 Rab6 独立的 MR1 配体呈递机制 细胞外肺部病原体为肺炎链球菌和金黄色葡萄球菌。我们将确定 AEC 中的运输分子对于细胞外病原体配体的呈递至关重要 确定这些分子如何影响细菌感染和 MR1 的细胞定位。