Visualizing epithelial network connectivity in thymus biology, aging, and regeneration

胸腺生物学、衰老和再生中上皮网络连接的可视化

• 批准号: 9383719
• 负责人: Dawen Cai
• 金额: $ 47.44万
• 依托单位: SCRIPPS FLORIDA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-20 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9383719
• 关键词: Address; Adolescence; Adopted; Age; Aging; Area; Atrophic; Behavior; Belief; Biology; Biology of Aging; Blood; Blood Cells; Castration; Cell Aging; Cell Lineage; Cell Proliferation; Cell physiology; Cells; Cellular Morphology; Cellular Structures; Cellularity; Characteristics; Data; Databases; Dependence; Development; Disease; Elements; Epithelial; Epithelial Cells; Exhibits; Fibroblasts; Gene Expression Regulation; Genes; Genetic; Genetic Transcription; Health; Hematopoietic stem cells; Hemorrhage; Imaging technology; Immune; Immune system; Immunity; Individual; Knowledge; Life; Lymphocyte; Lymphocyte Count; Lymphoid; Memory; Microtomy; Mission; Modeling; Morphology; Mus; Natural regeneration; Nature; Neurosciences; Organ; Organism; Output; Pathologic; Phenotype; Population; Process; Production; Proliferating; Radial; Recruitment Activity; Reporter; Reticular Cell; Role; Self Tolerance; Shapes; Site; Slice; Staining method; Stains; Stem cells; Stimulus; Stromal Cells; Supporting Cell; Surface; T-Cell Development; T-Lymphocyte; Techniques; Testing; Thick; Thymic epithelial cell; Thymus Gland; Tissue imaging; Tissues; Translations; United States National Institutes of Health; age related; aged; cell type; cellular imaging; data mining; experience; middle age; mouse model; optical imaging; organizational structure; premature; progenitor; stem-like cell

Project summary. T lymphocytes are cells of the immune system that, like all blood cells, are routinely lost throughout life and must be replenished. The thymus is the primary site for T lymphocyte production. However, it contains no lymphoid stem cells, and instead depends on continuous importation of stem-like cells that circulate in the blood. Microenvironmental conditions unique to the thymus then instruct these stem-like cells to proliferate and differentiate into T lineage cells that recognize foreign substances but are tolerant to self. The durable thymic microenvironment is established by its stromal cells, consisting primarily of epithelial cells (thymic epithelial cells, TEC). TEC form a pervasive reticular matrix (network) upon which lymphocyte development depends, and competition for the TEC network limits lymphoid cellularity in the thymus, and thus T cell output. For reasons that are still not understood, the thymus exhibits premature and accelerated age-related atrophy, a disorder that is primarily a consequence of changes in TEC. Importantly, the thymus retains latent potential for short-lived regeneration, which can be induced by stimuli such as surgical castration. The mechanisms of this process are not well known, but are believed to require proliferation of TEC cells themselves, or expansion of a TEC precursor population. We have generated a large temporo-spatial database of global stromal gene transcription during induced regrowth. Multiple independent data mining approaches have consistently indicated that genes associated with projection, extension, and outgrowth of cellular processes, such as those that characterize the TEC network, are dynamically regulated during regeneration. To begin to evaluate the role of TEC projections in lymphoid development, thymic aging, and thymic regeneration, we have adopted contemporary neuroscience imaging technologies (Rosa26[Brainbow 2.1], a.k.a. Confetti) in thick organ slices to visualize individual TEC and the TEC network. We find that the morphology of individual TEC, particularly those in the cortex (cTEC), is vastly different than what is suggested by conventional immuno-staining of thin sections, with overall globular rather than radially aligned reticular shapes, each possessing elaborate processes that envelop large numbers of lymphocytes. In the `aged' thymus (from 6 month-old Confetti mice), these processes become both shorter and thinner, and thus provide a diminished surface for lymphoid contact that explains reduced cellularity with age. We predict that rather than TEC proliferation, surgical castration will induce the (transient) lengthening and strengthening of these processes, thus increasing lymphocyte production. Testing this hypothesis is a key objective in this project, but in order to accomplish this, we are first obligated to establish a baseline in the healthy state for TEC and the TEC network. The proposed project relies heavily on established and emerging neuroscience paradigms, and is consistent with the stated mission of the NIH to “to seek fundamental knowledge about the nature and behavior of living systems, and the application of that knowledge to enhance health…and reduce illness.”

项目总结。 T淋巴细胞是免疫系统的细胞，像所有的血细胞一样，在一生中经常丢失， 必须补充。胸腺是T淋巴细胞产生的主要部位。但是，它不包含 淋巴干细胞，取而代之依赖于持续输入在体内循环的干细胞样细胞 血。胸腺特有的微环境条件然后指示这些干细胞样细胞增殖和 分化成能识别异物但对自身有耐受性的T细胞。持久的胸腺 微环境是由其基质细胞建立的，主要由上皮细胞(胸腺上皮细胞)组成 Cells，TEC)。TEC形成淋巴细胞发育所依赖的普遍的网状基质(网络)， 对TEC网络的竞争限制了胸腺中淋巴细胞的数量，从而限制了T细胞的输出。为 原因尚不清楚，胸腺表现出过早和加速的年龄相关性萎缩， 这种紊乱主要是由于TEC的变化造成的。重要的是，胸腺保留了潜在的 短暂的再生，可以通过手术阉割之类的刺激来诱导。这其中的机制 这一过程并不为人所知，但被认为需要TEC细胞本身的增殖，或者需要一种 TEC前身人口。我们已经生成了一个全球基质基因的大型时空数据库 诱导再生过程中的转录。多种独立的数据挖掘方法一致地 表明与细胞过程的投射、延伸和生长相关的基因，如那些 在再生过程中被动态调节。开始评估 TEC投射在淋巴发育、胸腺衰老和胸腺再生中的作用 当代神经科学成像技术(ROSA26[Brain弓2.1]，又名。五彩纸屑)厚厚的器官切片 以可视化单个TEC和TEC网络。我们发现单个TEC的形态，特别是 在大脑皮层(CTEC)，与传统的薄层免疫染色显示的结果有很大的不同 具有整体球状而不是径向排列的网状形状的部分，每个部分都具有精心设计的 包裹大量淋巴细胞的过程。在“老化”的胸腺(来自6个月大的五彩纸屑小鼠)中， 这些突起变得更短更薄，因此为淋巴接触提供了一个缩小的表面。 这就解释了细胞密度随年龄增长而减少的原因。我们预测，手术去势不会导致TEC增殖，而是 诱导这些过程(短暂的)延长和加强，从而增加淋巴细胞 制作。验证这一假设是这个项目的一个关键目标，但为了实现这一点，我们首先 有义务为TEC和TEC网络建立健康状态的基线。拟议的项目依赖于 大量依赖于已建立的和新兴的神经科学范例，并与 美国国立卫生研究院到“寻求关于生命系统的性质和行为的基本知识，以及应用 增强健康…的知识并减少疾病的发生。