Fig. 1.

FOXA2 expression is depleted in area of human COPD airways overexpressing mucus. Lung sections of de-identified healthy donors and COPD patients at Gold stage IV (#1) and Gold stage III (#2) with stable disease who underwent lobectomy were double-stained with primary antibodies against FOXA2 and mucus secreting cell-specific markers MUC5AC and MUC5B. Nuclei in airway cells were stained with DAPI (blue). Labeled airway sections were visualized by secondary antibodies conjugated to Alexa Fluor 594 (red, FOXA2) and to Alexa Fluor 488 (cyan-green, MUC5AC and MUC5B), respectively. Original magnification: 100x. ‘A’ indicate open airway lumens. White arrows indicate airway surface epithelial cells in healthy control lungs and airway basal epithelial cells in COPD lungs that still express FOXA2, which is absent in the surface epithelial cells expressing both MUC5AC and MUC5B in COPD lungs. Two representative healthy sections and four representative COPD sections are shown. Analysis of an additional lung sample is presented in Fig. S1.