REGULATION OF AIRWAY PROGENITOR CELL FATE IN DEVELOPMENT AND REGENERATION

描述(由申请人提供)：本修订申请的总体目标是研究在成年生活的发育和再生过程中，气道祖细胞获得和平衡其不同细胞表型的机制。更具体地说，我们将重点介绍Notch的作用及其在Ascl1对细胞命运的选择中的作用，这些细胞在发育中的呼吸道和损伤后重新填充的呼吸道中的选择。我们最近报道，胚胎呼吸道上皮细胞中的Notch信号对于建立分泌和非分泌细胞命运的平衡是必不可少的。Notch信号的中断阻止了Clara细胞的形成，并导致呼吸道充斥着神经内分泌和纤毛细胞。Notch如何影响细胞命运选择？哪些配体对这一过程至关重要，他们是否在呼吸道中推动了任何特定的谱系计划？对成年小鼠的研究表明，对这种化合物具有抵抗力的Clara细胞群能够产生平衡比例的分泌细胞和纤毛细胞。这是如何实现的，目前尚不清楚。我们有初步证据表明，Notch可能调节这一过程。在这里，我们建议通过三个具体目标来解决这些问题。目的1：研究不同Notch配体在锯齿或Delta配体失活的小鼠遗传模型中的作用，以平衡上皮细胞表型；目的2：利用活体和呼吸道上皮培养模型，研究表达Ascl1的细胞的谱系和命运及其在邻近呼吸道上皮中的影响；目的3：利用损伤修复的萘模型以及灭活Notch的药理学和遗传学方法，研究Notch介导的细胞命运选择在再生气道中的机制。 公共卫生相关性：本项目的目标是研究Notch途径和转录因子Ascl1(Achaete-scut1)在成人肺发育和再生过程中控制呼吸道上皮细胞命运的机制。我们将使用相关的小鼠遗传模型、原代呼吸道上皮培养系统和肺损伤修复模型来研究这些机制的具体方面。

DESCRIPTION (provided by applicant): The overall goal of this revised application is to investigate mechanisms by which airway progenitor cells acquire and balance their different cell phenotypes during development and during regeneration in adult life. More specifically, we will focus on the role of Notch and its regulation by Ascl1 in the selection of cell fates in developing airways and when airways are repopulated after injury. We have recently reported that Notch signaling in the embryonic airway epithelium is essential for establishing the balance of secretory and non-secretory cell fates. Disruption of Notch signaling prevents Clara cells from forming and results in airways overpopulated by neuroendocrine and ciliated cells. How does Notch influence cell fate selection? Which ligands are critical for this process and do they drive any specific lineage program in the airways? Studies in adult mice injured by Naphthalene suggest that a population of Clara cells resistant to this compound is able to give rise to a balanced proportion of secretory and ciliated cells. How this is achieved is currently unknown. We have preliminary evidence that Notch may regulate this process. Here we propose to address these issues in three specific aims. Aim 1: Study mechanisms that balance epithelial cell phenotypes looking at the role of different Notch ligands in mouse genetic models in which Jagged or Delta ligands were inactivated; Aim 2: Characterize lineage and fate of Ascl1-expressing cells and their influence in the neighbor airway epithelium using in vivo and airway epithelial culture models, and, Aim 3: Investigate mechanisms of Notch-mediated cell fate choice in regenerating airways using a Naphthalene model of injury repair and pharmacologic and genetic approaches to inactivate Notch. PUBLIC HEALTH RELEVANCE: The goal of this project is to study the mechanisms by which the Notch pathway and the transcription factor Ascl1 (Achaete-scute 1) control cell fate in the airway epithelium during development and regeneration in the adult lung. We will study specific aspects of these mechanisms using relevant mouse genetic models, primary airway epithelial culture systems and a model of lung injury-repair.