There are, besides Remdesivir (RDV), no approved antivirals for the treatment and/or prophylaxis of SARS-CoV-2 infections. To aid in the search for antivirals against this virus, we explored the use of human tracheal airway epithelial cells (HAEC) and human small airway epithelial cells (HsAEC) grown at the air/liquid interface (ALI) and infected at the apical side with either one of two different SARS-CoV-2 isolates. The virus was shown to replicate to high titers for extended periods of time (at least 8 days) and, in particular an isolate with the D614G in the spike (S) protein did so more efficiently at 35°C than at 37°C. The effect of a selected panel of reference drugs that were added to the culture medium at the basolateral side of the system was explored. GS-441524 (the parent nucleoside of Remdesivir), EIDD-1931 (the active metabolite of Molnupiravir) and IFN (β1 and λ1) all resulted in a dose-dependent inhibition of viral RNA and infectious virus titers at the apical side. However, AT-511 (a guanosine nucleotide previously reported to inhibit SARS-CoV-2) failed to inhibit viral replication. Together, these results provide a reference for further studies aimed at selecting SARS-CoV-2 inhibitors for further preclinical and clinical development.
Intermittent exposure to whole cigarette smoke alters the differentiation of primary small airway epithelial cells in the air-liquid interface culture
