SSA Stem cell regulation in the adult thymus

胸腺是适应性免疫系统的关键器官，在整个生命周期中负责T细胞的产生。该器官有一个复杂和高度组织的结构和细胞性，这与它产生功能T细胞库的不同过程密切相关。在不同的胸腺内细胞类型中，一组特化的胸腺上皮细胞(TEC)提供了T细胞库发育所需的大部分功能。我们有兴趣开发基于干细胞的方法来增强或取代患者的胸腺功能。通过前期工作，我们确定转录因子FOXN1是TEC分化的主要调节因子。最近，我们发现FOXN1上调可以使老年动物的胸腺恢复活力(Bredenkamp Development 2014)，并且FOXN1在一种非胸腺细胞类型的成纤维细胞中的表达迫使这些细胞改变身份并成为功能性TEC(Bredenkamp自然细胞生物学2014)。我们称这些重新编程的细胞为诱导的TEC(ITEC)。此外，我们已经在成人胸腺中发现了TEC干细胞群体(Ulyancenko...Blackburn，提交)。该项目将通过研究TEC干细胞在成人器官中是如何控制的，并确定TEC干细胞是否可以通过重新编程来产生，从而进一步发展这项工作。作为这项工作的一部分，我们将研究转录因子对TEC干细胞中Foxn1表达的控制，以及来自其他类型胸腺细胞的信号如何影响TEC干细胞的自我更新和分化。该项目将使用一系列最先进的方法来识别和验证TEC干细胞中的转录控制网络，包括遗传分析(例如，体内和体外的条件敲除、基因下调和过度表达方法的分析)、高分辨率显微镜、多参数流式细胞仪、基因表达分析(RNAseq和RT-qPCR)。所有必需的方法都可以在布莱克本实验室或客户关系管理系统中找到。这名学生还将从欧盟资助的ThymiStem财团(www.Thymiem.org)提供的培训和交流机会中受益。

The thymus is a key organ of the adaptive immune system, responsible for T cell production throughout the lifespan. The organ has an intricate and highly organised architecture and cellularity, which is intimately linked to the different processes via which it produces a functional T cell repertoire. Of the different intrathymic cell-types, an array of specialized thymic epithelial cells (TEC) provides most of the functions required for T cell repertoire development. We are interested in developing stem cell-based approaches to boosting or replacing thymus function in patients. Through previous work, we identified the transcription factor, FOXN1, as a master regulator of TEC differentiation. Recently, we have shown that FOXN1 up-regulation can rejuvenate the thymus in aged animals (Bredenkamp Development 2014), and that expression of FOXN1 in a non-thymic cell-type, fibroblasts, forces these cells to change identity and become functional TEC (Bredenkamp Nature Cell Biology 2014). We call these reprogrammed cells induced TEC (iTEC). Additionally, we have identified a TEC stem cell population in the adult thymus (Ulyanchenko ...Blackburn, submitted). This project will further develop this work, by investigating how TEC stem cells are controlled in the adult organ and determining whether TEC stem cells can be generated by reprogramming. As part of this work, we will investigate transcription factor control of Foxn1 expression in TEC stem cells, and how self-renewal and differentiation of TEC stem cells is influenced by signals from other intrathymic cell types. The project will utilise a range of state-of-the-art approaches to identify and validate transcriptional control networks in TEC stem cell, including genetic analyses (e.g. analysis of conditional knockouts, gene knock-down and over-expression approaches in vivo and in vitro), high resolution microscopy, multi-parameter flow cytometry, gene expression analysis (RNAseq and RT-qPCR). All of the required approaches are available within the Blackburn lab or within CRM. The student will also benefit from training and exchange opportunities available through the EU-funded consortium ThymiStem (www.thymistem.org).