p63+/Krt5+ Distal Airway Stem Cells are Essential for Lung Regeneration (tracheal epithelium and alveoli). Mus musculus

The possibility of lung regeneration has been long discounted due to the irreversible nature of chronic lung diseases. However, patients who sustain massive loss of lung tissue during acute infections often recover full pulmonary function. Correspondingly, we previously demonstrated lung regeneration in mice following H1N1 influenza virus infection and implicated p63+Krt5+ distal airway stem cells, or DASCp63/Krt5, in this process. We show here that rare, preexisting DASCp63/K5 undergo a proliferative expansion in response to influenza and lineage-trace to nascent alveoli assembled at sites of interstitial inflammation. We also show that the ablation of DASCp63/Krt5 in vivo prevents the regeneration of lung tissue following influenza leading to pre-fibrotic lesions and deficient oxygen exchange. Finally, we demonstrate that exogenously cloned and propagated DASCp63/Krt5 readily contribute to lung regeneration following transplantation. These data suggest that DASCp63/K5 are required for lung regeneration and may have therapeutic utility in acute and chronic lung diseases. Overall design: Tracheal epithelium and alveoli of healthy mice were laser capture microdissected for microarray analysis. Damaged lung interstitium (CD45+ region) of influenza infected (75pfu H1N1, 15dpi) mice were also dissected. Duplicates were included for each sample. We used the Affymetrix Mouse Exon 1.0 ST platform

长期以来，受慢性肺部疾病具有不可逆性的认知局限，肺再生的可能性一直未被重视。然而，在急性感染期间出现大量肺组织丢失的患者，往往能够完全恢复肺功能。与之对应，我们此前已证实H1N1流感病毒感染后的小鼠可发生肺再生，并确定p63+Krt5+远端气道干细胞（p63+Krt5+ distal airway stem cells，简称DASCp63/Krt5）参与了该过程。本研究显示，罕见的预先存在的DASCp63/Krt5会在流感病毒感染后发生增殖扩增，并通过谱系示踪定位至间质性炎症部位形成的新生肺泡。我们还证实，体内清除DASCp63/Krt5会阻断流感感染后的肺组织再生，进而引发前纤维化病灶并导致气体交换功能受损。最后，我们证明外源克隆扩增的DASCp63/Krt5在移植后可有效促进肺再生。上述数据表明，DASCp63/Krt5是肺再生所必需的细胞群，或可在急性与慢性肺部疾病中具备治疗应用价值。实验整体设计：对健康小鼠的气管上皮与肺泡组织进行激光捕获显微切割，以开展基因芯片分析。同时对感染流感病毒（75噬斑形成单位H1N1，感染后15天）的小鼠的受损肺间质（CD45阳性区域）进行显微切割。每个样本均设置重复样本。本研究采用Affymetrix小鼠外显子1.0 ST芯片平台。