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. 2022 Jun 16;13(4):e00519-22. doi: 10.1128/mbio.00519-22

FIG 5.

FIG 5

Possible involvement of ADAM-10 in the metalloproteinase-dependent entry of SARS-CoV-2. (a) Effects of metalloproteinase inhibitors on the entry of pseudoviruses bearing SARS-CoV-2 S or VSV G in VeroE6 and HEC50B cells in the presence of E-64d and in A704 cells in the absence of E-64d. The relative pseudovirus entry was calculated by normalizing the FL activity for each condition to the FL activity of cells infected with pseudovirus in the presence of DMSO alone, which was set to 100%. Values are means ± SD (n = 3/group). Data were compared with those obtained from cells infected with pseudoviruses bearing SARS-CoV-2 S in the presence of E-64d for HEC50B and VeroE6 cells and in the presence of DMSO alone for A704 cells. *, P < 0.05; **, P < 0.01. Cont, control (cells infected with pseudovirus without S protein); marima, marimastat; prinoma, prinomastat; iloma, ilomastat; CTS, CTS-1027; UK, UK370106; GW, GW280264X; GI, GI254023X; MLN, MLN-4760; BK, BK-1361; MMP2/9i, MMP2/9 inhibitor I; MMP9i, MMP9 inhibitor I. (b) Effects of the ADAM10 knockdown on ACE2 (top), ADAM10 (middle), and tubulin (bottom) expression. HEC50B cells were transfected with two distinct control siRNAs or three distinct siRNAs against ADAM10 for 48 h. (c) Effect of the ADAM10 knockdown on the entry of pseudoviruses bearing SARS-CoV-2 S, SARS-CoV S, MERS-CoV S, or VSV G. HEC50B cells were transfected with siRNAs for 48 h and then infected with pseudoviruses. Relative pseudovirus entry was calculated by normalizing the FL activity for each condition to the FL activity of cells infected with pseudovirus in the absence of siRNA (mock), which was set to 100%. Values are means ± SD (n = 3/group). *, P < 0.05; **, P < 0.01. (d and e) Effect of ADAM10 knockdown on the patterns of the entry pathways for SARS-CoV-2 S pseudovirus in HEC50B cells. HEC50B cells were transfected with siRNAs for 48 h and then infected with pseudoviruses in the presence of drugs. Values are means ± SD (n = 3/group). **, P < 0.01. E-64d, 25 μM E-64d; marima, 1 μM marimastat. Data are displayed as the conditions of siRNA treatment (d) and drug treatment (e).