Cell Type-Specific Anti-Viral Effects of Novel SARS-CoV-2 Main Protease Inhibitors

Abstract

Recently, we have described novel pyridyl indole esters and peptidomimetics as potent inhibitors of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) main protease. Here, we analysed the impact of these compounds on viral replication. It has been shown that some antivirals against SARS-CoV-2 act in a cell line-specific way. Thus, the compounds were tested in Vero, Huh-7, and Calu-3 cells. We showed that the protease inhibitors at 30 µM suppress viral replication by up to 5 orders of magnitude in Huh-7 cells, while in Calu-3 cells, suppression by 2 orders of magnitude was achieved. Three pyridin-3-yl indole-carboxylates inhibited viral replication in all cell lines, indicating that they might repress viral replication in human tissue as well. Thus, we investigated three compounds in human precision-cut lung slices and observed donor-dependent antiviral activity in this patient-near system. Our results provide evidence that even direct-acting antivirals may act in a cell line-specific manner.

Azido-Ceramides, a Tool to Analyse SARS-CoV-2 Replication and Inhibition—SARS-CoV-2 Is Inhibited by Ceramides

“…First, we analyzed whether AKS461 would suppress SARS-CoV-2 similarly to C6-ceramides. Since we and others have described that compounds inhibit SARS-CoV-2 replication in a cell line-specific way, three different cell lines were analyzed [ 7 ]. Thus, the cytotoxicity of AKS461 was analyzed by determining the cell growth rate after 72 h in Vero and Huh-7 cells as described before [ 7 , 29 ].…”

“…Since we and others have described that compounds inhibit SARS-CoV-2 replication in a cell line-specific way, three different cell lines were analyzed [ 7 ]. Thus, the cytotoxicity of AKS461 was analyzed by determining the cell growth rate after 72 h in Vero and Huh-7 cells as described before [ 7 , 29 ]. Similarly, MTT assays were performed after 72 h in Calu-3 cells since automated cell counting failed with this cell line [ 7 ].…”

“…Thus, the cytotoxicity of AKS461 was analyzed by determining the cell growth rate after 72 h in Vero and Huh-7 cells as described before [ 7 , 29 ]. Similarly, MTT assays were performed after 72 h in Calu-3 cells since automated cell counting failed with this cell line [ 7 ]. AKS461 showed cytotoxicity at 30 µM in these cell lines.…”

“…While many SARS-CoV-2 studies focus on targeting viral proteins such as the polymerase [ 1 ], the spike protein [ 2 , 3 ], or the main protease [ 4 , 5 , 6 , 7 ], fewer address the possibility of intervening in the host metabolism to impede virus entry or replication [ 8 , 9 , 10 ]. In this context, sphingolipid metabolism is a promising target because it has been revealed to be crucial for many viral and bacterial infections [ 11 , 12 , 13 , 14 , 15 ].…”

Progress of Section “Biochemistry” in 2022

“…The antiviral landscape was obviously dominated by SARS-CoV-2 studies. Interesting SARS-CoV-2 main protease inhibitors were reported by Geiger et al [ 45 ], whereas Ma et al [ 46 ] identified darunavir derivatives which effectively inhibit the cysteine-like protease of this virus. Many studies on monoclonal antibodies targeting various proteins of the virus were also ultimately published [ 47 , 48 , 49 , 50 , 51 ], although the role of these therapeutics in the management of COVID-19 was very much re-dimensioned due to mutations and loss of efficacy as well as the design of small molecule inhibitors targeting various viral proteins [ 52 , 53 ].…”