Functional interrogation of a novel SCGB3A2+/SFTPB+ cell in the human airway

摘要 在最近对发育中的人肺进行的单细胞RNA测序分析中，我们发现了一个细胞 以独特的基因表达谱为特征的群体，这是以前在 人或小鼠的肺。这些细胞表达SCGB3A2/SFTPB/CFTR，但缺乏其他细胞的标志 以俱乐部细胞(SCGB1A1)或离子细胞(FOXI1)等细胞类型为特征。我们将这些称为胎儿呼吸道 分泌型(Fas)细胞在转录信号中表达几个分泌基因。 由于对Fas细胞一无所知，而且在小鼠肺中也没有类似的群体，因此 这项建议的首要目标是详细描述这些细胞，询问它们的分化 潜力，并确定这些细胞是如何调节的。通过使用发育中的人的体外模型 肺上皮细胞称为人芽尖祖细胞(BTP)-类有机物，初步数据显示BTP-类有机物 在呼吸道分化过程中可以同时产生TP63+祖细胞和Fas细胞，而这种分化 可通过TGFb/BMP/SMAD信号进行调制。基于单细胞条形码的血统追踪 从BTP到呼吸道的转变表明，Fas细胞或基底细胞的克隆产生了不同的亚群 呼吸道细胞，Fas细胞产生肺神经内分泌细胞(PNECs)和C6+细胞亚群 多纤毛(MC)细胞，而TP63+祖细胞分化为分泌细胞和MUC16+MC细胞。基座 根据这些数据，我们将检验Fas细胞分化为不同的气道祖细胞的最重要的假设 这导致了呼吸道细胞类型的子集。考虑到这种细胞类型的新颖性，以及我们使用的独特工具 已经开发出在体外评估分化的人类上皮细胞，了解这个细胞群体将 提供对人类肺部生物学的基础性、描述性和机械性见解。

ABSTRACT During a recent single cell RNA sequencing analysis of the developing human lung, we identified a cell population characterized by a unique gene expression profile that has not previously been reported in the human or mouse lung. These cells express SCGB3A2/SFTPB/CFTR, but lack markers for other well characterized cell types such as club cells (SCGB1A1) or ionocytes (FOXI1). We refer to these as Fetal Airway Secretory (FAS) cells given the expression of several secretory genes within the transcriptional signature. Since nothing is known about FAS cells, and there is no analogous population in the murine lung, the overarching goal of this proposal is to both describe these cells in detail, to interrogate their differentiation potential, and to determine how these cells are regulated. By using an in vitro model of the developing human lung epithelium called human Bud Tip Progenitor (BTP)-organoids, preliminary data shows that BTP-organoids can give rise to both TP63+ progenitors and FAS cells during airway differentiation, and that this differentiation can be modulated by TGFb/BMP/SMAD signaling. Single cell barcode-based lineage tracing during the transition from BTP-to-airway suggest that clones of FAS cells or basal cells give rise to distinct subsets of airway cells, with FAS cells giving rise to pulmonary neuroendocrine cells (PNECs) and a subset of C6+ multiciliated (MC) cells, while TP63+ progenitor cells give rise to secretory cells and MUC16+ MC cells. Based on this data, we will test the overarching hypothesis that FAS cells differentiate distinct airway progenitor cell that give rise to a subset of airway cell types. Given the novelty of this cell type, and the unique tools that we have developed to assess the differentiating human epithelium in vitro, understanding this cell population will provide foundational descriptive and mechanistic insights into human lung biology.