ABSTRACT
SARS-CoV-2 is the causative agent behind the COVID-19 pandemic, responsible for over 170 million infections, and over 3.7 million deaths worldwide. Efforts to test, treat and vaccinate against this pathogen all benefit from an improved understanding of the basic biology of SARS-CoV-2. Both viral and cellular proteases play a crucial role in SARS-CoV-2 replication. Here, we study proteolytic cleavage of viral and cellular proteins in two cell line models of SARS-CoV-2 replication using mass spectrometry to identify protein neo-N-termini generated through protease activity. We identify previously unknown cleavage sites in multiple viral proteins, including major antigens S and N: the main targets for vaccine and antibody testing efforts. We discover significant increases in cellular cleavage events consistent with cleavage by SARS-CoV-2 main protease, and identify 14 potential high-confidence substrates of the main and papain-like proteases. We show that siRNA depletion of these cellular proteins inhibits SARS-CoV-2 replication, and that drugs targeting two of these proteins: the tyrosine kinase SRC and Ser/Thr kinase MYLK, show a dose-dependent reduction in SARS-CoV-2 titres. Overall, our study provides a powerful resource to understand proteolysis in the context of viral infection, and to inform the development of targeted strategies to inhibit SARS-CoV-2 and treat COVID-19.
Subject(s)
Antiviral Agents/pharmacology , COVID-19/metabolism , Protease Inhibitors/pharmacology , SARS-CoV-2/drug effects , Animals , Cell Line , Dipeptides/pharmacology , Humans , Mutation , Myosin-Light-Chain Kinase/antagonists & inhibitors , Myosin-Light-Chain Kinase/genetics , Myosin-Light-Chain Kinase/metabolism , Proteolysis , Proteomics , RNA, Small Interfering/pharmacology , SARS-CoV-2/genetics , Viral Proteases/metabolism , Viral Proteins/genetics , Viral Proteins/metabolism , Virus Internalization/drug effects , Virus Replication/drug effects , src-Family Kinases/antagonists & inhibitors , src-Family Kinases/genetics , src-Family Kinases/metabolism , COVID-19 Drug TreatmentABSTRACT
There is an urgent need for antiviral agents that treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We screened a library of 1900 clinically safe drugs against OC43, a human beta coronavirus that causes the common cold, and evaluated the top hits against SARS-CoV-2. Twenty drugs significantly inhibited replication of both viruses in cultured human cells. Eight of these drugs inhibited the activity of the SARS-CoV-2 main protease, 3CLpro, with the most potent being masitinib, an orally bioavailable tyrosine kinase inhibitor. X-ray crystallography and biochemistry show that masitinib acts as a competitive inhibitor of 3CLpro. Mice infected with SARS-CoV-2 and then treated with masitinib showed >200-fold reduction in viral titers in the lungs and nose, as well as reduced lung inflammation. Masitinib was also effective in vitro against all tested variants of concern (B.1.1.7, B.1.351, and P.1).
Subject(s)
Antiviral Agents/pharmacology , COVID-19 Drug Treatment , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus OC43, Human/drug effects , Cysteine Proteinase Inhibitors/pharmacology , SARS-CoV-2/drug effects , Thiazoles/pharmacology , A549 Cells , Animals , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Benzamides , COVID-19/virology , Catalytic Domain , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/metabolism , Coronavirus OC43, Human/physiology , Cysteine Proteinase Inhibitors/chemistry , Cysteine Proteinase Inhibitors/metabolism , HEK293 Cells , Humans , Inhibitory Concentration 50 , Mice , Mice, Transgenic , Microbial Sensitivity Tests , Piperidines , Pyridines , SARS-CoV-2/enzymology , SARS-CoV-2/physiology , Thiazoles/chemistry , Thiazoles/metabolism , Thiazoles/therapeutic use , Viral Load/drug effects , Virus Replication/drug effectsABSTRACT
The causative agent of the coronavirus disease 2019 (COVID-19) pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected millions and killed hundreds of thousands of people worldwide, highlighting an urgent need to develop antiviral therapies. Here we present a quantitative mass spectrometry-based phosphoproteomics survey of SARS-CoV-2 infection in Vero E6 cells, revealing dramatic rewiring of phosphorylation on host and viral proteins. SARS-CoV-2 infection promoted casein kinase II (CK2) and p38 MAPK activation, production of diverse cytokines, and shutdown of mitotic kinases, resulting in cell cycle arrest. Infection also stimulated a marked induction of CK2-containing filopodial protrusions possessing budding viral particles. Eighty-seven drugs and compounds were identified by mapping global phosphorylation profiles to dysregulated kinases and pathways. We found pharmacologic inhibition of the p38, CK2, CDK, AXL, and PIKFYVE kinases to possess antiviral efficacy, representing potential COVID-19 therapies.
Subject(s)
Betacoronavirus/metabolism , Coronavirus Infections/metabolism , Drug Evaluation, Preclinical/methods , Pneumonia, Viral/metabolism , Proteomics/methods , A549 Cells , Angiotensin-Converting Enzyme 2 , Animals , Antiviral Agents/pharmacology , COVID-19 , Caco-2 Cells , Casein Kinase II/antagonists & inhibitors , Casein Kinase II/metabolism , Chlorocebus aethiops , Coronavirus Infections/virology , Cyclin-Dependent Kinases/antagonists & inhibitors , Cyclin-Dependent Kinases/metabolism , HEK293 Cells , Host-Pathogen Interactions , Humans , Pandemics , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors/pharmacology , Phosphorylation , Pneumonia, Viral/virology , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins/antagonists & inhibitors , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Receptor Protein-Tyrosine Kinases/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , p38 Mitogen-Activated Protein Kinases/metabolism , Axl Receptor Tyrosine KinaseABSTRACT
A newly described coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of coronavirus disease 2019 (COVID-19), has infected over 2.3 million people, led to the death of more than 160,000 individuals and caused worldwide social and economic disruption1,2. There are no antiviral drugs with proven clinical efficacy for the treatment of COVID-19, nor are there any vaccines that prevent infection with SARS-CoV-2, and efforts to develop drugs and vaccines are hampered by the limited knowledge of the molecular details of how SARS-CoV-2 infects cells. Here we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins that physically associated with each of the SARS-CoV-2 proteins using affinity-purification mass spectrometry, identifying 332 high-confidence protein-protein interactions between SARS-CoV-2 and human proteins. Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (of which, 29 drugs are approved by the US Food and Drug Administration, 12 are in clinical trials and 28 are preclinical compounds). We screened a subset of these in multiple viral assays and found two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the sigma-1 and sigma-2 receptors. Further studies of these host-factor-targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19.