MG-101 for COVID-19

AbstractThere are an urgent need for antivirals to treat the newly emerged SARS-CoV-2. To identify new candidates we screened a repurposing library of ~3,000 drugs. Screening in Vero cells found few antivirals, while screening in human Huh7.5 cells validated 23 diverse antiviral drugs. Extending our studies to lung epithelial cells, we found that there are major differences in drug sensitivity and entry pathways used by SARS-CoV-2 in these cells. Entry in lung epithelial Calu-3 cells is pH-independent and requires TMPRSS2, while entry in Vero and Huh7.5 cells requires low pH and triggering by acid-dependent endosomal proteases. Moreover, we found 9 drugs are antiviral in lung cells, 7 of which have been tested in humans, and 3 are FDA approved including Cyclosporine which we found is targeting Cyclophilin rather than Calcineurin for its antiviral activity. These antivirals reveal essential host targets and have the potential for rapid clinical implementation.

Considering the importance of the 2019 outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulting in the coronavirus disease 2019 (COVID-19) pandemic, an overview of two proteases that play an important role in the infection by SARS-CoV-2, the main protease of SARS-CoV-2 (MPro) and the host transmembrane protease serine 2 (TMPRSS2), is presented in this review. After summarising the viral replication cycle to identify the relevance of these proteases, the therapeutic agents already approved are presented. Then, this review discusses some of the most recently reported inhibitors first for the viral MPro and next for the host TMPRSS2 explaining the mechanism of action of each protease. Afterward, some computational approaches to design novel MPro and TMPRSS2 inhibitors are presented, also describing the corresponding crystallographic structures reported so far. Finally, a brief discussion on a few reports found some dual-action inhibitors for both proteases is given. This review provides an overview of two proteases of different origins (viral and human host) that have become important targets for the development of antiviral agents to treat COVID-19.