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

细胞迁移对于胸腺中的T细胞发育是必不可少的。胸腺细胞使用趋化因子和趋化因子受体移入和移出不同的胸腺微环境，以与其他细胞相互作用并接收分化为T细胞的信号。 细胞迁移的改变可导致缺陷性T细胞发育或自身免疫。我们目前对胸腺细胞如何控制其迁移的理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来直接研究整个器官水平的T细胞发育。我们的体内成像方法的结果为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：胸腺细胞显示出整体异质性迁移行为，缺乏可辨别的全局模式。然而，在同一发育阶段的胸腺细胞表现出特征性的迁移模式。在这个跨学科的项目中，我们将解决有关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相关的基本问题。我们利用我们开发的定量体内成像和尖端分子工具的独特组合来实时测量趋化因子和趋化因子受体的活性。高内涵的成像数据将提供丰富的时空分辨率，需要开发数学模型，以充分了解细胞动力学是如何调节胸腺。此外，我们将表征在转录和翻译后水平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.