FIG 5.

Cell composition of polarized human airway epithelial cultures (HAEC) and cytotoxicity of PF-00835231 and remdesivir. (a) Schematic representation of a transwell containing a polarized HAEC in air-liquid interface. Dark blue, cycling basal cells; light blue, basal cells; red, suprabasal cells; purple, secretory cells; yellow, microfold cells; green, ciliated cells; gray, mucus. To test for cytotoxicity, drugs were added to the medium in the basolateral chamber. (b) Clustered uniform manifold approximation and projection (UMAP) of single cells determined by single-cell RNA sequencing from n = 3 uninfected HAEC. Clusters were determined by markers from the literature (37, 38) and by differentially expressed marker genes for each cluster determined by Wilcoxon test. (c and d) Representative cross-sections of uninfected HAEC at 72 h post treatment with 10 μM PF-00835231 or 10 μM remdesivir. Hematoxylin and eosin (H&E) (c) or periodic acid-Schiff (PAS)–alcian blue toe staining (d). (e) Transepithelial resistance (TEER) in drug-treated, uninfected HAEC over time as a measure of epithelial integrity. Means ± SEM from n = 3 independent experiments. (f) CellTiter-Glo assay on undifferentiated, basal-like Bci-NS1.1 precursor cells. Means ± SEM from n = 3 independent experiments.