Fig. 1

The characteristics of Omicron infection in airway epithelial cells (AECs) and the inhibitory effect of dicoumarol (DCM) on viral infection. Cultured primary AECs were infected with SARS-CoV-2 Omicron BA.1 at a multiplicity of infection (MOI) of 0.1 (a). The cell-free SARS-CoV-2 N gene were measured in the supernatant of cultured AECs derived from nasal (n = 4), large airway (n = 5) and small airway (n = 4) (b). Representative images of AECs with Omicron infection were observed by scanning electron microscopy (c) and transmission electron microscopy (d). The basolateral side of the AECs culture was treated with DCM at concentration of 0 μM to 250 μM (n = 3–6 at each concentration) (e). The antiviral effect (f, g) and cell cytotoxicity (g) of DCM treatment in AECs were measured. Representative immunofluorescence images showed that DCM markedly reduced the proportion of infected cells (N protein positive) at concentration of 200 μM (h). Data are represented as mean ± SEM