FIGURE 2.

VIP and PACAP reduce SARS‐CoV‐2 RNA synthesis in human primary monocytes and viral replication in pulmonary cells, protecting them from virus‐mediated cytopathic effects. Monocytes (A and B) and Calu‐3 cells (C and D) were exposed (overnight) or not to the indicated concentrations of VIP (A and C) or PACAP (B and D). Culture medium was removed and then cells were infected with SARS‐CoV‐2 for 1 h, as described in Material and Methods. After infection, viral input was removed and cells were washed, then reexposed to the neuropeptides. Viral RNA synthesis was evaluated by qPCR in monocytes 24 h after infection. In Calu‐3 cells, supernatants were collected at 48 h after infection, and viral replication was evaluated by quantifying PFUs in Vero E6 plaque assays. Cellular viability was analyzed by measuring LDH release in the supernatants of uninfected or SARS‐CoV‐2‐infected monocytes (E) treated or not with VIP or PACAP (10 nM), and Calu‐3 cells (F) treated or not with VIP (1 nM) or PACAP (50 nM). Data in (A and B) are shown normalized to infected cells kept only with culture medium, and in (C, D, E, and F) represent means ± sd of absolute values. */#, p ≤ 0.05; **/##, p ≤ 0.01; ns, not significant; (A, B, and E) n = 6; (C, D, and F) n = 5. Each dot represents an independent assay with 3 replicates