Real-time quantitative in vivo imaging of chemokine and chemokine receptors dynamics during intrathymic cell migration

细胞迁移是胸腺T细胞发育所必需的。胸腺细胞利用趋化因子和趋化因子受体迁入和迁出不同的胸腺微环境，与其他细胞相互作用，并接收分化为T细胞的信号。细胞迁移的改变可能导致T细胞发育缺陷或自身免疫。我们目前对胸腺细胞如何控制其迁移的了解来自于对培养细胞的研究或对固定组织切片的分析。目前还不清楚胸腺细胞如何控制它们在胸腺内的迁移行为，在那里它们会遇到来自各种来源的多种化学线索。我们最近建立了一个新的系统，直接在整个器官水平上研究T细胞的发育。我们的体内成像方法的结果为研究全功能胸腺中所有胸腺细胞的迁移行为提供了有价值的见解：胸腺细胞总体上表现出异质性的迁移行为，缺乏可辨别的整体模式。而处于同一发育阶段的胸腺细胞则表现出特有的迁移模式。在这个跨学科的项目中，我们将解决胸腺细胞如何感知和响应不同的胸腺微环境以及T细胞分化如何与细胞相互作用和迁移行为联系在一起的基本问题。我们利用体内定量成像和我们开发的尖端分子工具的独特组合，实时测量趋化因子和趋化因子受体的活性。高含量的成像数据将提供丰富的时空分辨率，这是开发数学模型以充分了解胸腺中细胞动力学是如何调节所需的。此外，我们将在转录和翻译后水平上描述调控趋化因子受体表达的分子机制。从体内系统获得的结果将深入了解T细胞发育的动态方面，这将与人类系统相关。

Cell migration is essential for T cell development in the thymus. Thymocytes use chemokine and chemokine receptors to migrate in and out of distinct thymic microenvironments to interact with other cells and receive signals for their differentiation into T cells. Alteration of cell migration can results in either defective T cell development or autoimmunity. Our current understanding how thymocytes control their migration derives from studies of cultured cells or analysis on fixed tissue sections. It is unclear how thymocytes control their migratory behavior within the thymus, where they encounter multiple chemical cues from various sources. We have recently established a new system to directly study T cell development at whole organ level. The outcomes of our in vivo imaging approach have provided valuable insights into the migration behavior of all thymocytes in a full functional thymus: Thymocytes show an overall heterogeneous migratory behavior, lacking a discernable global pattern. However, thymocytes at the same developmental stage exhibit characteristic migratory pattern. In this interdisciplinary project, we will address fundamental questions regarding how do thymocytes sense and respond to distinct thymic microenvironments and how is T cell differentiation linked to cell interaction and migration behavior. We take advantages of a unique combination of quantitative in vivo imaging and cutting edge molecular tools, which we have developed, to measure the activity of chemokine and chemokine receptors in real-time. High-content imaging data will provide the rich spatiotemporal resolution that is needed to develop mathematical models to fully understand how cell dynamics is regulated in the thymus. In addition, we will characterize the molecular mechanisms regulating the expression of chemokine receptors at the transcriptional and post-translations levels. The outcomes obtained from the in vivo system will gain insight into the dynamic aspects of T cell development, which will be of relevance to the human system.