ABSTRACT
SARS-CoV-2 Nsp15 is a uridine-specific endoribonuclease with C-terminal catalytic domain belonging to the EndoU family that is highly conserved in coronaviruses. As endoribonuclease activity seems to be responsible for the interference with the innate immune response, Nsp15 emerges as an attractive target for therapeutic intervention. Here we report the first structures with bound nucleotides and show how the enzyme specifically recognizes uridine moiety. In addition to a uridine site we present evidence for a second base binding site that can accommodate any base. The structure with a transition state analog, uridine vanadate, confirms interactions key to catalytic mechanisms. In the presence of manganese ions, the enzyme cleaves unpaired RNAs. This acquired knowledge was instrumental in identifying Tipiracil, an FDA approved drug that is used in the treatment of colorectal cancer, as a potential anti-COVID-19 drug. Using crystallography, biochemical, and whole-cell assays, we demonstrate that Tipiracil inhibits SARS-CoV-2 Nsp15 by interacting with the uridine binding pocket in the enzyme's active site. Our findings provide new insights for the development of uracil scaffold-based drugs.
Subject(s)
Antiviral Agents/pharmacology , COVID-19 Drug Treatment , COVID-19/virology , Endoribonucleases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Pyrrolidines/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Thymine/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , A549 Cells , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Catalytic Domain , Crystallography, X-Ray , Endoribonucleases/chemistry , Endoribonucleases/metabolism , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacokinetics , Humans , Ligands , Models, Molecular , Protein Conformation , Pyrrolidines/chemistry , Pyrrolidines/pharmacokinetics , Thymine/chemistry , Thymine/pharmacokinetics , Uridine/metabolism , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolismABSTRACT
Porcine epidemic diarrhea virus (PEDV), being highly virulent and contagious in piglets, has caused significant damage to the pork industries of many countries worldwide. There are no commercial drugs targeting coronaviruses (CoVs), and few studies on anti-PEDV inhibitors. The coronavirus 3C-like protease (3CLpro) has a conserved structure and catalytic mechanism and plays a key role during viral polyprotein processing, thus serving as an appealing antiviral drug target. Here, we report the anti-PEDV effect of the broad-spectrum inhibitor GC376 (targeting 3Cpro or 3CLpro of viruses in the picornavirus-like supercluster). GC376 was highly effective against the PEDV 3CLpro and exerted similar inhibitory effects on two PEDV strains. Furthermore, the structure of the PEDV 3CLpro in complex with GC376 was determined at 1.65 Å. We elucidated structural details and analyzed the differences between GC376 binding with the PEDV 3CLpro and GC376 binding with the transmissible gastroenteritis virus (TGEV) 3CLpro. Finally, we explored the substrate specificity of PEDV 3CLpro at the P2 site and analyzed the effects of Leu group modification in GC376 on inhibiting PEDV infection. This study helps us to understand better the PEDV 3CLpro substrate specificity, providing information on the optimization of GC376 for development as an antiviral therapeutic against coronaviruses.
Subject(s)
Antiviral Agents/pharmacology , Peptide Hydrolases/chemistry , Porcine epidemic diarrhea virus/drug effects , Protease Inhibitors/pharmacology , Pyrrolidines/pharmacology , Animals , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Catalytic Domain , Chlorocebus aethiops , Crystallography, X-Ray , Models, Molecular , Peptide Hydrolases/metabolism , Porcine epidemic diarrhea virus/enzymology , Porcine epidemic diarrhea virus/physiology , Protease Inhibitors/chemistry , Protease Inhibitors/metabolism , Pyrrolidines/chemistry , Pyrrolidines/metabolism , Substrate Specificity , Sulfonic Acids , Transmissible gastroenteritis virus/enzymology , Vero Cells , Virus Replication/drug effectsABSTRACT
COVID-19 emerges as a pandemic disease with high mortality. Development of effective prevention and treatment is an urgent need. We reviewed TH17 responses in patients with SARS-CoV-2 and proposed an FDA approved JAK2 inhibitor Fedratinib for reducing mortality of patients with TH17 type immune profiles.
Subject(s)
Coronavirus Infections/drug therapy , Cytokine Release Syndrome/drug therapy , Janus Kinase 2/antagonists & inhibitors , Pneumonia, Viral/drug therapy , Pyrrolidines/pharmacology , Sulfonamides/pharmacology , Th17 Cells/immunology , Betacoronavirus/immunology , COVID-19 , Coronavirus Infections/pathology , Cytokines/biosynthesis , Cytokines/immunology , Humans , Pandemics , Pneumonia, Viral/pathology , SARS-CoV-2ABSTRACT
COVID-19 was declared a pandemic on March 11 by WHO, due to its great threat to global public health. The coronavirus main protease (Mpro, also called 3CLpro) is essential for processing and maturation of the viral polyprotein, therefore recognized as an attractive drug target. Here we show that a clinically approved anti-HCV drug, Boceprevir, and a pre-clinical inhibitor against feline infectious peritonitis (corona) virus (FIPV), GC376, both efficaciously inhibit SARS-CoV-2 in Vero cells by targeting Mpro. Moreover, combined application of GC376 with Remdesivir, a nucleotide analogue that inhibits viral RNA dependent RNA polymerase (RdRp), results in sterilizing additive effect. Further structural analysis reveals binding of both inhibitors to the catalytically active side of SARS-CoV-2 protease Mpro as main mechanism of inhibition. Our findings may provide critical information for the optimization and design of more potent inhibitors against the emerging SARS-CoV-2 virus.
Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , Proline/analogs & derivatives , Protease Inhibitors/pharmacology , Pyrrolidines/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/pharmacology , Betacoronavirus/enzymology , Binding Sites/drug effects , COVID-19 , Catalytic Domain , Chlorocebus aethiops , Coronavirus 3C Proteases , Crystallography, X-Ray , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/metabolism , Disease Models, Animal , High-Throughput Screening Assays , Models, Molecular , Pandemics , Proline/pharmacology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , RNA-Dependent RNA Polymerase/chemistry , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2 , Sulfonic Acids , Vero Cells , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects , COVID-19 Drug TreatmentABSTRACT
The main protease, Mpro (or 3CLpro) in SARS-CoV-2 is a viable drug target because of its essential role in the cleavage of the virus polypeptide. Feline infectious peritonitis, a fatal coronavirus infection in cats, was successfully treated previously with a prodrug GC376, a dipeptide-based protease inhibitor. Here, we show the prodrug and its parent GC373, are effective inhibitors of the Mpro from both SARS-CoV and SARS-CoV-2 with IC50 values in the nanomolar range. Crystal structures of SARS-CoV-2 Mpro with these inhibitors have a covalent modification of the nucleophilic Cys145. NMR analysis reveals that inhibition proceeds via reversible formation of a hemithioacetal. GC373 and GC376 are potent inhibitors of SARS-CoV-2 replication in cell culture. They are strong drug candidates for the treatment of human coronavirus infections because they have already been successful in animals. The work here lays the framework for their use in human trials for the treatment of COVID-19.
Subject(s)
Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus, Feline/drug effects , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , A549 Cells , Animals , Antiviral Agents/chemistry , Betacoronavirus/enzymology , Binding Sites , Chlorocebus aethiops , Coronavirus 3C Proteases , Coronavirus, Feline/enzymology , Crystallography, X-Ray , Cysteine Endopeptidases/chemistry , Cytopathogenic Effect, Viral/drug effects , Drug Repositioning , Humans , Inhibitory Concentration 50 , Molecular Structure , Prodrugs , Protease Inhibitors/chemistry , Pyrrolidines/chemistry , Pyrrolidines/pharmacology , Severe acute respiratory syndrome-related coronavirus/drug effects , Severe acute respiratory syndrome-related coronavirus/enzymology , SARS-CoV-2 , Sulfonic Acids , Vero Cells , Viral Nonstructural Proteins/chemistry , Virus Replication/drug effectsABSTRACT
We started a study on the molecular docking of six potential pharmacologically active inhibitors compounds that can be used clinically against the COVID-19 virus, in this case, remdesivir, ribavirin, favipiravir, galidesivir, hydroxychloroquine and chloroquine interacting with the main COVID-19 protease in complex with a COVID-19 N3 protease inhibitor. The highest values of affinity energy found in order from highest to lowest were chloroquine (CHL), hydroxychloroquine (HYC), favipiravir (FAV), galidesivir (GAL), remdesivir (REM) and ribavirin (RIB). The possible formation of hydrogen bonds, associations through London forces and permanent electric dipole were analyzed. The values of affinity energy obtained for the hydroxychloroquine ligands was -9.9 kcal/mol and for the chloroquine of -10.8 kcal/mol which indicate that the coupling contributes to an effective improvement of the affinity energies with the protease. Indicating that, the position chosen to make the substitutions may be a pharmacophoric group, and cause changes in the protease.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Cysteine Endopeptidases/chemistry , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry , Adenine/administration & dosage , Adenine/analogs & derivatives , Adenine/chemistry , Adenine/pharmacology , Adenosine/analogs & derivatives , Adenosine Monophosphate/administration & dosage , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/chemistry , Adenosine Monophosphate/pharmacology , Alanine/administration & dosage , Alanine/analogs & derivatives , Alanine/chemistry , Alanine/pharmacology , Amides/administration & dosage , Amides/chemistry , Amides/pharmacology , Antiviral Agents/administration & dosage , Binding Sites , COVID-19 , Chloroquine/administration & dosage , Chloroquine/chemistry , Chloroquine/pharmacology , Coronavirus 3C Proteases , Drug Interactions , Humans , Hydrogen Bonding , Hydroxychloroquine/administration & dosage , Hydroxychloroquine/chemistry , Hydroxychloroquine/pharmacology , Ligands , Molecular Docking Simulation , Nanotechnology , Pandemics , Protease Inhibitors/administration & dosage , Pyrazines/administration & dosage , Pyrazines/chemistry , Pyrazines/pharmacology , Pyrrolidines/administration & dosage , Pyrrolidines/chemistry , Pyrrolidines/pharmacology , Ribavirin/administration & dosage , Ribavirin/chemistry , Ribavirin/pharmacology , SARS-CoV-2 , Static Electricity , COVID-19 Drug TreatmentABSTRACT
The coronavirus (CoV) disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is a health threat worldwide. Viral main protease (Mpro, also called 3C-like protease [3CLpro]) is a therapeutic target for drug discovery. Herein, we report that GC376, a broad-spectrum inhibitor targeting Mpro in the picornavirus-like supercluster, is a potent inhibitor for the Mpro encoded by SARS-CoV-2, with a half-maximum inhibitory concentration (IC50) of 26.4 ± 1.1 nM. In this study, we also show that GC376 inhibits SARS-CoV-2 replication with a half-maximum effective concentration (EC50) of 0.91 ± 0.03 µM. Only a small portion of SARS-CoV-2 Mpro was covalently modified in the excess of GC376 as evaluated by mass spectrometry analysis, indicating that improved inhibitors are needed. Subsequently, molecular docking analysis revealed that the recognition and binding groups of GC376 within the active site of SARS-CoV-2 Mpro provide important new information for the optimization of GC376. Given that sufficient safety and efficacy data are available for GC376 as an investigational veterinary drug, expedited development of GC376, or its optimized analogues, for treatment of SARS-CoV-2 infection in human is recommended.