Intrinsic and extrinsic control of epithelial tissue stem cell activity

项目总结 组织干细胞是一种罕见的未分化细胞，能够自我更新，对 为它们所在组织的动态平衡和再生提供动力。它们通常是静止的，而且 当被激活时，它们会增殖和分化，产生具有特殊功能的成熟细胞类型。茎 细胞活动由内在基因表达程序和来自细胞的信号共同控制 周围组织微环境。剖析支配干细胞的内在和外在机制 静止和激活不仅对获得组织和干细胞的基础知识很重要 生物学，也是为了了解如何在组织工程和再生中操纵细胞命运 医药。无数的再生上皮组织，如乳腺、皮肤和前列腺，房屋干细胞 在它们的基底细胞隔间。我们使用两种哺乳动物组织，乳腺和皮肤，每个组织都有它的 独特的优势和临床相关性，作为研究全身和组织的免费模型系统- 调节基底细胞命运和干细胞活动的特定机制。我们的研究已经 阐明关键转录因子和染色质因子在乳腺和皮肤基底/干细胞基因中的功能 调控，以及这些因子如何与主要信号通路相互作用，以控制激活，增殖， 基底干细胞的分化和上皮-间充质可塑性。单细胞技术的最新进展 测序技术使我们能够系统地探索细胞和分子的异质性 乳腺和皮肤基底细胞，允许更深入和更全面地了解它们的 组成和特征，并为干细胞中的事件序列提供新的见解 激活和分化。在未来五年，我们会继续采用跨专业的方法。 结合单细胞基因组学和空间基因表达图谱与组织特异性基因敲除和 血统追踪、体内和体外干细胞分析以及分子研究，以解决两个主要问题 关于乳腺基础干细胞的知识差距：如何维持和激活它们的静止状态 实现了扩容。具体地说，我们将测试创新假设，即低水平的Wnt/b-连锁素 基底细胞和特定巨噬细胞亚群之间的信号和分子交叉对话对 维持基础干细胞的静止状态。我们还将描述一种新的功能和调节 发现了作为运输扩增祖细胞的基底细胞亚群，这些细胞充当主力驱动基底细胞 乳腺上皮形态发生、动态平衡和再生过程中的细胞扩张。何时何地 适用，我们将对皮肤进行平行分析，以确定潜在的一般原则和 基础细胞-巨噬细胞交叉对话的基本策略。我们的发现将揭示新的内在和外在的 基础干细胞静止和活跃扩增的调节者。这方面的知识是预防 干细胞枯竭和再生性疾病以及了解癌细胞休眠。

PROJECT SUMMARY Tissue stem cells are rare, undifferentiated cells that are capable of self-renewal and are essential for fueling the homeostasis and regeneration of the tissue in which they reside. They are often quiescent, and when activated, they proliferate and differentiate to produce mature cell types with specialized functions. Stem cell activities are jointly controlled by the intrinsic gene expression program and the signals from the surrounding tissue microenvironment. Dissecting the intrinsic and extrinsic mechanisms that govern stem cell quiescence and activation is important not only for gaining fundamental knowledge of tissue and stem cell biology, but also for understanding how to manipulate cell fates in tissue engineering and regenerative medicine. Myriad regenerative epithelial tissues, such as mammary gland, skin, and prostate, house stem cells in their basal cell compartment. We use two mammalian tissues, mammary gland and skin, each with its unique advantages and clinical relevance, as complimentary model systems to study both general and tissue- specific mechanisms underlying the regulation of basal cell fate and stem cell activities. Our research has elucidated the function of key transcription and chromatin factors in mammary and skin basal/stem cell gene regulation, and how these factors interface with major signaling pathways to control the activation, proliferation, differentiation, and epithelial-mesenchymal plasticity of basal stem cells. The recent advent of single-cell sequencing technology has enabled us to systematically probe the cellular and molecular heterogeneities of mammary and skin basal cells, allowing a deeper and more comprehensive understanding of their compositions and characteristics as well as providing novel insights into the sequence of events in stem cell activation and differentiation. In the next five years, we will continue to employ a multi-disciplinary approach combining single-cell genomics and spatial gene expression mapping with tissue-specific gene knockout and lineage tracing, in vivo and ex vivo stem cell assays, as well as molecular studies to address two major knowledge gaps regarding mammary basal stem cells: how their quiescence is maintained and active expansion is achieved. Specifically, we will test the innovative hypothesis that a low level of Wnt/b-catenin signaling and molecular cross-talks between basal cells and specific macrophage subsets are critical for maintaining basal stem cell quiescence. We will also characterize the novel function and regulation of a newly discovered subset of basal cells as transit amplifying progenitor cells that serve as workhorses to drive basal cell expansion during mammary epithelial morphogenesis, homeostasis, and regeneration. When and where applicable, we will perform parallel analysis on skin in order to identify potentially general principles and strategies underlying basal cell-macrophage cross-talks. Our findings will expose novel intrinsic and extrinsic regulators of basal stem cell quiescence and active expansion. This knowledge is fundamental to preventing stem cell depletion and regenerative diseases as well as to understanding cancer cell dormancy.