Fig. 4.

COPD-related abnormalities in epithelial differentiation.

a) FOXJ1⁺ cells percentage is decreased in the airway epithelium from COPD2 and COPD3–4 patients, as compared with non-smokers and smoker controls.

b-c) FOXJ1⁺ cells percentage significantly correlates to both total (b) and active (c) β-catenin staining, in terms of percentage of positive area.

d) MUC5AC⁺ cells percentage is increased in the airway epithelium from COPD2 and COPD3–4 patients, as compared with non-smokers and smoker controls.

e-f) MUC5AC⁺ cells percentage significantly correlates to both total (e) and active (f) β-catenin staining, in terms of percentage of positive area.

g) Basal cell populations, assessed by p63⁺ cells, did not vary in COPD as compared with (non-) smoker controls.

h-i) Representative pictures of FOXJ1 (g) and MUC5AC (h) staining in bronchial sections of non-smoker controls and very severe COPD patients.

*, ** indicate p-values of less than 0•05 and 0•01, respectively (analysed using the Kruskal-Wallis test followed by Dunn's post-hoc test). Bars indicate median ± interquartile range. COPD, chronic obstructive pulmonary disease; NS, non-smokers; Smo, smokers. Scale bars, 50 µm.