Fig. 5: Airway surface ACE2 protein is regulated by IL-13 and viral infection.

a–c Immunofluorescence staining of in vitro nasal airway epithelial ALI cultures (derived from a single GALA II asthmatic child) derived from vehicle-treated (a), 5 days IL-13(10 ng mL⁻¹) treated (b), and 24 h HRV-A infected epithelium (c). Representative images of ciliated cells (ACT; red) and ACE2-positive (white) cells. The nuclei were counterstained with DAPI (blue). ACE2 protein was located in the apical compartment and decreased with IL-13 treatment and increased in HRV-A infection. Scale bars: 60 μm. d Zoomed in image of c. e Quantification of apical ACE2-positive cells per 20x field for each condition in the IL-13/HRV mature culture stimulation experiment (n = 1 donor). p-values were obtained from a two-sided t-test. Data are presented as mean values ± SEM. f–h Immunofluorescence staining of in vitro nasal airway epithelial ALI cultures from a single child non-asthmatic donor derived from vehicle-treated (f), 21 days IL-13 (10 ng mL⁻¹) treated (g), and 21 days DAPT(5 μM) treated epithelium (h). Representative images of ciliated cells (ACT; red), basal cells (KRT5; green), and ACE2-positive (white) cells. The nuclei were counterstained with DAPI (blue). ACE2 protein located in the apical compartment and decreased in IL-13 treatment and increased in DAPT treatment. Scale bars: 60 μm. i Quantification of apical ACE2-positive cells per 20x field for each condition in the IL-13/DAPT differentiation experiment (n = 1 donor). p-values were obtained from a two-sided t-test. Data are presented as mean values ± SEM. j Immunofluorescence staining of in vivo trachea tissues from a single healthy donor. Representative images of ciliated cells (ACT; red), basal cells (KRT5; green), and ACE2-positive (white) cells. The nuclei were counterstained with DAPI (blue). ACE2 protein located in the apical compartment of ACT positive ciliated cells. Scale bars: 60 μm. All images were captured on the Echo Revolve R4 and images were cropped and resized using Affinity Designer. For each image, brightness and contrasts were uniformly adjusted relative to the brightest feature to balance exposure of each color channel.