A revised airway epithelial hierarchy includes CFTR-expressing ionocytes

Nature. 2018 Aug;560(7718):319-324. doi: 10.1038/s41586-018-0393-7. Epub 2018 Aug 1.


The airways of the lung are the primary sites of disease in asthma and cystic fibrosis. Here we study the cellular composition and hierarchy of the mouse tracheal epithelium by single-cell RNA-sequencing (scRNA-seq) and in vivo lineage tracing. We identify a rare cell type, the Foxi1+ pulmonary ionocyte; functional variations in club cells based on their location; a distinct cell type in high turnover squamous epithelial structures that we term 'hillocks'; and disease-relevant subsets of tuft and goblet cells. We developed 'pulse-seq', combining scRNA-seq and lineage tracing, to show that tuft, neuroendocrine and ionocyte cells are continually and directly replenished by basal progenitor cells. Ionocytes are the major source of transcripts of the cystic fibrosis transmembrane conductance regulator in both mouse (Cftr) and human (CFTR). Knockout of Foxi1 in mouse ionocytes causes loss of Cftr expression and disrupts airway fluid and mucus physiology, phenotypes that are characteristic of cystic fibrosis. By associating cell-type-specific expression programs with key disease genes, we establish a new cellular narrative for airways disease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Asthma / genetics
  • Cell Differentiation / genetics*
  • Cell Lineage / genetics*
  • Cystic Fibrosis / genetics*
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics*
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism*
  • Female
  • Forkhead Transcription Factors / deficiency
  • Forkhead Transcription Factors / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation
  • Goblet Cells / cytology
  • Goblet Cells / metabolism
  • Humans
  • Lung / cytology
  • Male
  • Mice
  • Sequence Analysis, RNA
  • Single-Cell Analysis
  • Trachea / cytology


  • CFTR protein, human
  • Cftr protein, mouse
  • Forkhead Transcription Factors
  • Foxi1 protein, mouse
  • Cystic Fibrosis Transmembrane Conductance Regulator