The contribution of GPCRs to thymocyte medullary entry and central tolerance

GPCR 对胸腺细胞髓质进入和中枢耐受的贡献

• 批准号: 9011993
• 负责人: Lauren Ilyse Richie EHRLICH
• 金额: $ 37.32万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-15 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9011993
• 关键词: Affect; Affinity; Antigen Receptors; Antigens; Apoptosis; Atypical lymphocyte; Autoantigens; Autoimmune Diseases; Autoimmune Process; Autoimmunity; Automobile Driving; CD8B1 gene; Candidate Disease Gene; Cells; Defect; Dendritic Cells; Disease; Ensure; Epithelial Cells; Etiology; Expression Library; Flow Cytometry; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; Gene Rearrangement; Genes; Genetic; Genetic Recombination; Goals; Health; Human; Image; Individual; Knockout Mice; Left; Life; Location; Maintenance; Major Histocompatibility Complex; Microscopy; Modeling; Molecular; Molecular Profiling; Mouse Strains; Mus; Nature; Open Reading Frames; Organ; Patients; Peripheral; Process; Production; Proteins; Role; Self Tolerance; Slice; Stromal Cells; Syndrome; T-Cell Antigen Receptor Specificity; T-Cell Development; T-Cell Receptor; T-Lymphocyte; Testing; Thymic epithelial cell; Thymus Gland; Transgenic Organisms; adaptive immunity; base; cell motility; central tolerance; combinatorial; defined contribution; gain of function; migration; mouse model; novel; novel therapeutics; pathogen; prevent; receptor; thymocyte; two-photon

DESCRIPTION (provided by applicant): In this project we propose to determine the role of candidate G protein-coupled receptors (GPCRs) in enforcing deletion of developing auto-reactive T cells in the thymus. In order for T cells to recognize and respond to the wide array of pathogens encountered throughout life, each cell expresses a unique antigen receptor, the T cell receptor (TCR), that is capable of recognizing and responding to individual pathogens. These vastly diverse receptors are generated by random and imprecise rearrangements of gene segments encoding the TCR. Unfortunately, this random recombination process also yields autoreactive TCRs that could induce autoimmune diseases. To prevent overt autoimmunity, developing T cells are educated in the thymus through interactions with thymic stromal cells: thymocytes expressing overtly autoreactive TCRs are induced to undergo apoptosis. This process of thymic self-tolerance induction is referred to as central tolerance. Central tolerance i imposed largely within the interior, medullary region of the thymus, where thymocytes encounter a wide array of self-antigens expressed on stromal cells, namely dendritic cells and/or medullary thymic epithelial cells. It is critical that developing thymocytes enter the medulla and interact with stromal cells therein to eliminate autoreactive cells. From studies of Autoimmune Polyglandular Syndrome-I patients along with mouse models of this disorder, we know that if central tolerance induction in the medulla is impaired, multi-organ autoimmunity ensues. Based on our previous studies, GPCR signaling is required for thymocyte medullary entry. In this proposal, the role of candidate GPCRs in promoting medullary entry and self-tolerance will be evaluated. Using 2-photon microscopy, live thymocytes deficient for candidate GPCRs will be imaged to determine whether their ability to enter the medulla or to interact with medullary stromal cells is impaired. In a complementary set of traditional immunological approaches, murine models deficient for candidate GPCRs will be tested for overt autoimmunity, as well as for an inability to induce central tolerance to model medullary self- antigens. Finally, unbiased gain-of-function screens will identify additional molecular candidates that promote thymocyte medullary entry and self-tolerance. These studies will illuminate molecular mechanisms that promote thymocyte migration into the medulla and interactions with medullary stromal cells to promote central tolerance, thus broadening our understanding of the etiology of autoimmune diseases.

描述（由申请人提供）：在这个项目中，我们建议确定候选 G 蛋白偶联受体 (GPCR) 在强制删除胸腺中正在发育的自身反应性 T 细胞中的作用。为了让 T 细胞识别并响应一生中遇到的各种病原体，每个细胞都表达独特的抗原受体，即 T 细胞受体 (TCR)，它能够识别单个病原体并对其做出响应。这些极其多样化的受体是通过编码 TCR 的基因片段随机且不精确的重排而产生的。不幸的是，这种随机重组过程也会产生自身反应性 TCR，从而诱发自身免疫性疾病。为了防止明显的自身免疫，正在发育的 T 细胞通过与胸腺基质细胞的相互作用在胸腺中进行培养：表达明显自身反应性 TCR 的胸腺细胞被诱导发生凋亡。这种胸腺自我耐受诱导过程被称为中枢耐受。中枢耐受主要施加于胸腺的内部髓质区域，其中胸腺细胞遇到基质细胞（即树突状细胞和/或髓质胸腺上皮细胞）上表达的多种自身抗原。发育中的胸腺细胞进入髓质并与其中的基质细胞相互作用以消除自身反应性细胞至关重要。通过对自身免疫性多腺体综合征-I 患者以及该疾病的小鼠模型的研究，我们知道，如果髓质中的中枢耐受诱导受损，就会发生多器官自身免疫。根据我们之前的研究，GPCR 信号是胸腺细胞进入髓质所必需的。在本提案中，将评估候选 GPCR 在促进髓质进入和自我耐受方面的作用。使用 2 光子显微镜，将对缺乏候选 GPCR 的活胸腺细胞进行成像，以确定它们进入髓质或与髓质基质细胞相互作用的能力是否受损。在一组互补的传统免疫学方法中，将测试候选GPCR缺陷的小鼠模型的明显自身免疫性，以及无法诱导对模型髓质自身抗原的中枢耐受性。最后，无偏见的功能获得筛选将识别出促进胸腺细胞髓质进入和自我耐受的其他候选分子。这些研究将阐明促进胸腺细胞迁移到髓质以及与髓质基质细胞相互作用以促进中枢耐受的分子机制，从而拓宽我们对自身免疫性疾病病因学的理解。