Progenitors, Mechanisms of Differentiation, and Functions of Lung M Cells

已有研究表明，M细胞可以采集管腔抗原样本，并通过细胞转运将这些抗原输送到 抗原提呈树突状细胞。因此，它们是粘膜免疫的关键调节因子。尽管有一大堆 关于M细胞在其他粘膜器官中的免疫作用的文献，呼吸道M细胞直到最近才被描述 而且几乎还没有进行过功能或分子表征。我们提出了第一个单细胞转录本 并识别调节炎症的呼吸道M细胞信号级联反应。我们发现 呼吸道M细胞在小鼠气管中以孤立细胞的形式出现，在小鼠的小气道中以斑块的形式出现，我们报道 人呼吸道M细胞向原代人呼吸道上皮定向分化的研究。最后，我们证明了 呼吸道M细胞是通过给予信号因子RANKL，内毒素(LPS)治疗， 和流感感染。有趣的是，M细胞可以作为孤立细胞出现，但在生理刺激的环境中，如内毒素 或流感感染时，M细胞斑块与淋巴滤泡相关，提示上皮免疫功能正常 单位。 在这项赠款申请中，我们建议利用我们在干细胞生物学、上皮生物学、肺 炎症和流感感染来定义肺M细胞的功能生物学。我们将从定义细胞 小鼠和人类呼吸道M细胞的起源。我们现在已经产生了一组全面的小鼠基因驱动程序 追踪所有呼吸道上皮细胞的谱系。在这里，我们建议部署这套小鼠系，首次 时间，以便准确地定义所有可能产生M细胞的亲代上皮细胞类型。我们还将 阐明RANKL-RANK信号通路在小鼠炎症模型中的作用。最后，定义呼吸道M细胞 功能，我们构建了一个新的Sox8-Creer驱动程序鼠标，它允许我们专门标记、遗传修改和 消融M细胞。我们将把这些遗传试剂与现有的小鼠疾病模型结合起来，以阐明 M细胞在呼吸道炎症和流感感染模型中的功能作用。最后，我们将剖析分子 两种候选趋化因子控制M细胞-免疫细胞相互作用的遗传学和药理学机制 手法结合新型气管移植和肺切片活体成像平台。

M cells have been shown to sample luminal antigens and use transcytosis to deliver these antigens to underlying antigen presenting dendritic cells. Thus, they serve as key regulators of mucosal immunity. Despite the vast body of literature on the immunologic role of M cells in other mucosal organs, airway M cells have only recently been described and almost no functional or molecular characterization has been performed. We present the first single cell transcriptomes of murine airway M cells and identify airway M cell signaling cascades that regulate inflammation. We have discovered that airway M cells occur as solitary cells in the murine trachea and as patches in the murine small airway, and we report the directed differentiation of human airway M cells from primary human airway epithelium. Finally, we demonstrate that airway M cells are induced by the administration of the signaling factor RANKL, treatment with Lipopolysaccharide (LPS), and influenza infection. Interestingly, M cells can occur as solitary cells, but in the setting of physiologic stimuli like LPS or influenza infection, patches of M cells are associated with lymphoid follicles suggesting a functional epithelial-immune unit. In this grant application, we propose to use our combined expertise in stem cell biology, epithelial biology, lung inflammation, and influenza infection to define the functional biology of lung M cells. We will start by defining the cellular origins of murine and human airway M cells. We have now generated a comprehensive battery of murine genetic driver lines for lineage tracing all the cells of airway epithelium. Herein, we propose to deploy this set of murine lines, for the first time, in order to precisely define all the putative parental epithelial cell types that can give rise to M cells. We will also clarify the role of RANKL-RANK signaling pathways in murine models of inflammation. Finally, to define airway M cell functions, we constructed a new Sox8-CreER driver mouse that allows us to specifically label, genetically modify, and ablate M cells. We will integrate these genetic reagents with existing murine disease models to elucidate the role of functional roles of M cells in models of airway inflammation and influenza infection. Lastly, we will dissect the molecular mechanisms of two candidate chemokines that govern M cell-immune cell interactions using genetic and pharmacological manipulation in combination with a novel tracheal explant and lung slice live imaging platform.