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，与所有血细胞一样，在整个生命过程中都会定期丢失，并且 胸腺是 T 淋巴细胞产生的主要场所，但它不含 T 淋巴细胞。 淋巴干细胞，而是依赖于持续输入干细胞样细胞来彻底改变淋巴干细胞 然后，胸腺特有的微环境条件指示这些干细胞样细胞增殖和增殖。 分化为识别外来物质但对自身具有耐受性的 T 谱系细胞。 微环境是由其基质细胞建立的，基质细胞主要由上皮细胞（胸腺上皮细胞）组成 细胞，TEC）。TEC 形成淋巴细胞发育所依赖的普遍网状基质（网络）， TEC 网络的竞争限制了胸腺中的淋巴细胞结构，从而限制了 T 细胞的输出。 由于尚不清楚的原因，胸腺表现出过早且加速的与年龄相关的萎缩， 主要是 TEC 变化的结果，重要的是，胸腺保留了潜在的潜力。 短暂的再生，可以通过手术去势等刺激来诱导。 该过程尚不为人所知，但据信需要 TEC 细胞本身的增殖，或 我们已经生成了一个大型的全球基质基因时空数据库。 诱导再生过程中的转录一致。 表明与细胞过程的投射、延伸和生长相关的基因，例如 TEC 网络的特征，在再生过程中进行动态调节。 为了了解 TEC 预测在淋巴发育、胸腺衰老和胸腺再生中的作用，我们采用了 厚器官切片中的当代神经科学成像技术（Rosa26[Brainbow 2.1]，又名五彩纸屑） 可视化单个 TEC 和 TEC 网络 我们发现单个 TEC 的形态，特别是。 皮层（cTEC）中的那些，与薄层细胞的传统免疫染色所建议的有很大不同。 部分，整体呈球状而不是径向排列的网状形状，每个部分都拥有精心设计的 在“老化”的胸腺中（来自 6 个月大的五彩纸屑小鼠）， 这些过程变得更短、更薄，从而为淋巴接触提供了更小的表面 这解释了随着年龄的增长，细胞结构减少，而不是 TEC 增殖，手术去势将会减少。 诱导这些过程的（暂时）延长和加强，从而增加淋巴细胞 测试这个假设是这个项目的一个关键目标，但为了实现这一目标，我们首先要做的是 有义务为 TEC 和 TEC 网络建立健康状态基线。 很大程度上依赖于已建立的和新兴的神经科学范式，并且与该组织的既定使命是一致的 NIH“寻求有关生命系统的性质和行为的基础知识，以及应用 这些知识可以增强健康……并减少疾病。”