Fig 4. Diltiazem decreases the cell surface expression of ACE2.

(A and B) Vero-E6 cells were preincubated with diltiazem, then the expression of ACE2 on the cell surface and in the total cells was detected by western blotting (A) and flow cytometry (B), respectively. (C and D) Diltiazem-treated Vero-E6 cells, Vero-E6-ACE2 cells (C), A549 cells, or A549-ACE2 cells (D) were incubated with HRB25 (M.O.I. = 10) at 4°C for 1 h, then washed with PBS. The viral RNA level in the cell lysate was measured by qPCR. The expression of exogenous ACE2 was confirmed by western blotting. (E) Diltiazem-treated Vero-E6-ACE2 cells were infected with HRB25 (M.O.I. = 0.01), and the supernatants were harvested at 24 h post-infection for plaque assays. The data shown represent, or are from, three independent experiments or replicates (means ± SDs). The two-tailed unpaired Student’s t-test was used for the statistical analysis. ns, not significant, **p < 0.01, ***p < 0.001.