Figure 6.

U-exo treatment in human nasal epithelial cells (HNECs) cultured at the air-liquid interface (ALI) exhibits an antiviral effect. (A) A schematic representing the experimental design. The differentiation status of the HNECs cultured at the ALI was confirmed prior to their infection with IFV A/H1N1, or HCoV-OC43. The infected cells of the ALI culture model were subject to further analysis to determine the antiviral effects of U-exo treatment. (B) HNECs cultured at the ALI were infected with IFV A/H1N1, or HCoV-OC43 viruses (MOI= 10). Structural integrity of the epithelium was evaluated by staining E-cadherin (green) and goblet cells were visualized by MUC5AC (red) staining. Scale bar = 20 μm. (C) Apical side was infected with IFV A/H1N1, or HCoV OC43 viruses (MOI= 10) at the same time as treatment with control (Ctl), U-exo (Exo), IFN-α (10 ng/mL), IFN-α in combination with U-exo (IFN-α+Exo). After 90 min incubation, media was removed from the apical side, and media containing U-exo and/or IFN-α was added to the basolateral side. Viral gene expression levels were determined after 6 days using RT-qPCR. *p < 0.05; **p < 0.01; ***p < 0.001, versus Ctl-treated cells. (D) The supernatants from the basolateral side were harvested to measure the extracellular release of lactate dehydrogenase (LDH) levels. Data are shown as the mean ± standard deviation (SD) of two independent experiments. **p < 0.01; ***p < 0.001, versus Ctl-treated cells.