Figure 1
In vivo immunofluorescence analysis of human and porcine airway epithelium. Tracheal and bronchial tissue sections from human and porcine samples were stained for epithelial-specific, proliferation, epithelial barrier and clearance function markers. (a) CK7 (red) was mainly expressed in columnar epithelial cells, whereas CK5 (green) and CK14 (green) displayed the expected basal localization in both human and porcine samples. (b) Similarly to CK5 and CK14, the neurotrophin receptor p75NTR (red) was mainly detected in both species' basal layer of tracheal and bronchial sections, whereas proliferating Ki67 positive (green) cells, essential for the epithelial renewal, were randomly distributed within the basal and supra-basal layers. (c) The respiratory epithelial barrier function was highlighted by the continuous expression of the tight junctions’ protein ZO-1 (green) at the apical level. (d) Goblet cells were mainly localized in the sopra-basal layers, producing, storing, and releasing MUC5AC (red), one of the main gel-forming glycoproteins of airway mucus. Moreover, the continuous expression of acetylated tubulin (red) in the luminal side of the tracheobronchial epithelium in both species revealed a high in vivo density of the ciliated cells, essential for a functional mucociliary clearance. Nuclei were counterstained with DAPI, scale bar = 50 µm.
