Function of thymic epithelial cells in T lymphocyte maturation

胸腺上皮细胞在T淋巴细胞成熟中的功能

• 批准号: 7686243
• 负责人: You-Wen He
• 金额: $ 19.5万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7686243
• 关键词: Address; Aging; Antibodies; Autoimmune Diseases; CD8B1 gene; Cell Lineage; Cell Maturation; Cell surface; Cells; Cellularity; Chimeric Proteins; Complex; Data; Dendritic Cells; Development; Diphtheria Toxin; Disease; Effectiveness; Electron Microscopy; Elements; Endothelial Cells; Epithelial Cells; Epithelium; Extracellular Matrix; Fibroblasts; Flow Cytometry; Functional disorder; Funding; Genes; Genetic; Genetic Models; Goals; Green Fluorescent Proteins; Heterogeneity; Immunologic Deficiency Syndromes; In Vitro; Individual; Injection of therapeutic agent; Mediating; Modeling; Molecular; Morphology; Mus; Natural regeneration; Nature; Organogenesis; Other Genetics; Pathway interactions; Play; Population; Process; Proteins; Rejuvenation; Role; Signal Transduction; Staging; Stromal Cells; Structure; System; T-Lymphocyte; Testing; Thymic epithelial cell; Thymocyte Development; Thymus Gland; base; cell growth regulation; diphtheria toxin receptor; in vivo; macrophage; mouse model; novel; research study; thymocyte; tool

DESCRIPTION (provided by applicant): Multiple T cell lineages develop in the thymus through well-defined maturation pathways. The maturation of these T lineage cells requires continuous interaction between T cell precursors and the thymic microenvironment, which consists of various stromal cells including thymic cortical and medullary epithelial cells (cTECs and mTECs, respectively). It has been established that cTECs play critical roles in development of CD4- CD8- double negative thymocytes and positive selection while mTECs mediate negative selection and post-positive selection maturation. However, the mechanisms allowing cTECs and mTECs to deliver signals to different stages and different lineages of developing T cells remain unknown. The different fates of developing T cells are likely determined by their interactions with various subpopulations of TECs. It is well established that cTECs and mTECs display extensive heterogeneity. The highly complex nature of TECs strongly supports the hypothesis that individual subsets of TECs perform distinct functions in thymocyte maturation. However, this hypothesis has not been tested because it has not been possible to separate the function of the various cell subpopulations comprising the highly heterogeneous TEC compartment in vivo. To address this issue, we have developed several mouse genetic models that allow the selective deletion of distinct subpopulations of TECs in vivo and in vitro. We have inserted a fusion protein consisting of simian diphtheria toxin receptor- green fluorescent protein into the loci of individual genes expressed in subsets of cTECs or mTECs. In one such model, we show that injection of diphtheria toxin induces rapid deletion of cTECs and massive reduction in thymocytes, demonstrating the effectiveness of this approach in assessing the role of individual TECs in thymocyte maturation. In this proposal, we will investigate the roles of individual TEC subsets in thymocyte maturation using these genetic models. Data obtained from these experiments will provide valuable information about thymocyte-TEC interactions, and generate a framework for identification of novel molecular mechanisms involved in thymocyte development and selection. Importantly, these genetic models are also valuable tools to study cellular regulation of thymic organogenesis and regeneration.Narrative T lymphocytes undergo maturation in the thymus. This process depends on the microenvironment provided by the thymic structure. Thymic epithelial cells are important constituents of the thymic structure and provide indispensable signals for T lymphocyte maturation. Up to this point, how thymic epithelial cells support T lymphocyte maturation is largely unknown. However, understanding the function of thymic epithelial cells in supporting T cell maturation is essential to our understanding of immunodeficiency and autoimmune diseases as dysfunction of thymic epithelial cells causes these diseases. We propose to use genetic mouse models to dissect the function of different populations of thymic epithelial cells in thymocyte maturation. The results from our studies will help us to understand how autoimmune disease and immunodeficiency develop. In addition, these models can also be used to study thymic regeneration after aging.

描述（由申请人提供）：多种 T 细胞谱系通过明确的成熟途径在胸腺中发育。这些 T 谱系细胞的成熟需要 T 细胞前体与胸腺微环境之间的持续相互作用，胸腺微环境由各种基质细胞组成，包括胸腺皮质和髓质上皮细胞（分别为 cTEC 和 mTEC）。已经确定cTEC在CD4-CD8-双阴性胸腺细胞的发育和正选择中发挥关键作用，而mTEC介导负选择和正选择后成熟。然而，cTEC 和 mTEC 将信号传递到发育中 T 细胞的不同阶段和不同谱系的机制仍然未知。发育中的 T 细胞的不同命运可能是由它们与不同 TEC 亚群的相互作用决定的。众所周知，cTEC 和 mTEC 显示出广泛的异质性。 TEC 的高度复杂性有力地支持了这样的假设：TEC 的各个子集在胸腺细胞成熟中发挥着不同的功能。然而，这一假设尚未得到检验，因为不可能在体内分离构成高度异质 TEC 区室的各种细胞亚群的功能。为了解决这个问题，我们开发了几种小鼠遗传模型，可以在体内和体外选择性删除不同的 TEC 亚群。我们已将由猿白喉毒素受体 - 绿色荧光蛋白组成的融合蛋白插入到 cTEC 或 mTEC 子集中表达的单个基因的位点中。在一个这样的模型中，我们证明注射白喉毒素会诱导 cTEC 快速删除和胸腺细胞大量减少，证明了这种方法在评估单个 TEC 在胸腺细胞成熟中的作用方面的有效性。在本提案中，我们将使用这些遗传模型研究各个 TEC 亚群在胸腺细胞成熟中的作用。从这些实验中获得的数据将提供有关胸腺细胞-TEC 相互作用的有价值的信息，并生成一个框架来识别胸腺细胞发育和选择中涉及的新分子机制。重要的是，这些遗传模型也是研究胸腺器官发生和再生的细胞调节的宝贵工具。 叙述 T 淋巴细胞在胸腺中成熟。这个过程取决于胸腺结构提供的微环境。胸腺上皮细胞是胸腺结构的重要组成部分，为T淋巴细胞的成熟提供不可或缺的信号。到目前为止，胸腺上皮细胞如何支持 T 淋巴细胞成熟尚不清楚。然而，了解胸腺上皮细胞支持 T 细胞成熟的功能对于我们了解免疫缺陷和自身免疫性疾病至关重要，因为胸腺上皮细胞功能障碍会导致这些疾病。我们建议使用遗传小鼠模型来剖析不同群体的胸腺上皮细胞在胸腺细胞成熟中的功能。我们的研究结果将帮助我们了解自身免疫性疾病和免疫缺陷是如何发展的。此外，这些模型还可用于研究衰老后的胸腺再生。