Bronchioalveolar stem cells are a main source for regeneration of distal lung epithelia

Bronchioalveolar stem cells (BASCs) are a potential source for lung regeneration, but direct in vivo evidence is critically missing since specific genetic labeling of BASCs has not been possible. We developed a novel cell tracing approach based on intein-mediated assembly of newly engineered split-effectors, allowing selective targeting of dual-marker expressing BASCs. We found that BASCs generate the majority of distal lung airway cells after bronchioalveolar damage but only moderately contribute to cellular turnover under homeostatic conditions. Importantly, DTA-mediated ablation of BASCs compromised proper regeneration of distal airways. The study defines BASCs as crucial components of the lung repair machinery and provides a paradigmatic example for the detection and manipulation of stem cells that cannot be recognized by a single marker alone. Bulk RNAseq of FACS-isolated lung epithelial cell types (BASC/AT2/Club) in duplicates.支气管肺泡干细胞（Bronchioalveolar stem cells, BASCs）是肺再生的潜在细胞来源，但由于无法对BASCs实现特异性遗传标记，体内直接证据极度匮乏。我们开发了一种基于内含肽（intein）介导组装新型工程化分裂效应蛋白的细胞追踪新方法，可选择性靶向表达双标记物的BASCs。研究发现，在支气管肺泡损伤后，BASCs可生成远端肺气道细胞的绝大多数，但在稳态条件下仅适度参与细胞更新过程。值得注意的是，白喉毒素A（Diphtheria Toxin A, DTA）介导的BASCs清除会损害远端气道的正常再生功能。本研究明确BASCs是肺修复机制的关键组成部分，并为无法通过单一标记物识别的干细胞的检测与操控提供了范式范例。本研究对经荧光激活细胞分选（Fluorescence-Activated Cell Sorting, FACS）分离的肺上皮细胞类型（BASC/AT2/Club细胞）进行了重复批量RNA测序（bulk RNAseq）。