In this study, we show for the first time that NOTCH1 and NOTCH3 expression levels in the COPD airway epithelium are differentially regulated and respectively correlated with overexpression of the goblet cell marker MUC5AC and deficiency of the ciliated cell marker FOXJ1 (Figures 5, 7, 8). Here, FOXJ1 is linked to chronic obstructive pulmonary disease.