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1.
J Med Chem ; 65(8): 6231-6249, 2022 04 28.
Article in English | MEDLINE | ID: covidwho-1867997

ABSTRACT

Enzymes involved in RNA capping of SARS-CoV-2 are essential for the stability of viral RNA, translation of mRNAs, and virus evasion from innate immunity, making them attractive targets for antiviral agents. In this work, we focused on the design and synthesis of nucleoside-derived inhibitors against the SARS-CoV-2 nsp14 (N7-guanine)-methyltransferase (N7-MTase) that catalyzes the transfer of the methyl group from the S-adenosyl-l-methionine (SAM) cofactor to the N7-guanosine cap. Seven compounds out of 39 SAM analogues showed remarkable double-digit nanomolar inhibitory activity against the N7-MTase nsp14. Molecular docking supported the structure-activity relationships of these inhibitors and a bisubstrate-based mechanism of action. The three most potent inhibitors significantly stabilized nsp14 (ΔTm ≈ 11 °C), and the best inhibitor demonstrated high selectivity for nsp14 over human RNA N7-MTase.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/drug therapy , COVID-19/virology , Exoribonucleases/antagonists & inhibitors , Exoribonucleases/chemistry , Humans , Methyltransferases , Molecular Docking Simulation , RNA, Viral/genetics , S-Adenosylmethionine , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Sulfonamides/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry
2.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-336877

ABSTRACT

The binding of the SARS-CoV-2 spike to angiotensin-converting enzyme 2 (ACE2) promotes virus entry into the cell. Targeting this interaction represents a promising strategy to generate antivirals. By screening a phage-display library of biosynthetic protein sequences build on a rigid alpha-helicoidal HEAT-like scaffold (named αReps), we selected candidates recognizing the spike receptor binding domain (RBD). Two of them (F9 and C2) bind the RBD with affinities in the nM range, displaying neutralisation activity in vitro and recognizing distinct sites, F9 overlapping the ACE2 binding motif. The F9-C2 fusion protein and a trivalent αRep form (C2-foldon) display 0.1 nM affinities and EC 50 of 8-18 nM for neutralization of SARS-CoV-2. In hamsters, F9-C2 instillation in the nasal cavity before or during infections effectively reduced the replication of a SARS-CoV-2 strain harbouring the D614G mutation in the nasal epithelium. Furthermore, F9-C2 and/or C2-foldon effectively neutralized SARS-CoV-2 variants (including delta and omicron variants) with EC 50 values ranging from 13 to 32 nM. With their high stability and their high potency against SARS-CoV-2 variants, αReps provide a promising tool for SARS-CoV-2 therapeutics to target the nasal cavity and mitigate virus dissemination in the proximal environment. Author Summary The entry of SARS-CoV-2 in permissive cells is mediated by the binding of its spike to angiotensin-converting enzyme 2 (ACE2) on the cell surface. To select ligands able to block this interaction, we screened a library of phages encoding artificial proteins (named αReps) for binding to its receptor binding domain (RBD). Two of them were able to bind the RBD with high affinity and block efficiently the virus entry in cultured cells. Assembled αReps through covalent or non-covalent linkages blocked virus entry at lower concentration than their precursors (with around 20-fold activity increase for a trimeric αRep). These αReps derivates neutralize efficiently SARS-CoV-2 β, γ, δ and Omicron virus variants. Instillation of an αRep dimer in the nasal cavity effectively reduced virus replication in the hamster model of SARS-CoV-2 and pathogenicity.

3.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-332623

ABSTRACT

Recombination is a crucial process in the evolution of many organisms. Although the evolutionary reasons behind its occurrence in RNA viruses are debated, this phenomenon has been associated with major epidemiological events such as virus host range expansion, antigenic shift or variation in virulence 1,2, and this process occurs frequently in positive strand RNA viruses such as coronaviruses. The SARS-CoV-2 pandemic has been associated with the repeated emergence of variants of concern presenting increased transmissibility, severity or immune escape 3. The recent extensive circulation of Delta worldwide and its subsequent replacement by viruses of the Omicron lineage 4 (BA.1 then BA.2), have created conditions for genetic exchanges between viruses with both genetic diversity and phenotypic specificities 5-7. Here we report the identification and in vitro and in vivo characterization of a Delta-Omicron recombinant in Europe. This recombinant exhibits immune escape properties similar to Omicron, while its behavior in mice expressing the human ACE2 receptor is more similar to Delta. This recombinant provides a unique and natural opportunity to better understand the genotype to phenotype links in SARS-CoV-2.

4.
Sci Rep ; 12(1): 4683, 2022 03 18.
Article in English | MEDLINE | ID: covidwho-1751758

ABSTRACT

The emergence and rapid spread of the Omicron variant of SARS-CoV-2, which has more than 30 substitutions in the spike glycoprotein, compromises the efficacy of currently available vaccines and therapeutic antibodies. Using a clinical strain of the Omicron variant, we analyzed the neutralizing power of eight currently used monoclonal antibodies compared to the ancestral B.1 BavPat1 D614G strain. We observed that six of these antibodies have lost their ability to neutralize the Omicron variant. Of the antibodies still having neutralizing activity, Sotrovimab/Vir-7831 shows the smallest reduction in activity, with a factor change of 3.1. Cilgavimab/AZD1061 alone shows a reduction in efficacy of 15.8, resulting in a significant loss of activity for the Evusheld cocktail (42.6-fold reduction) in which the other antibody, Tixagevimab, does not retain significant activity against Omicron. Our results suggest that the clinical efficacy of the initially proposed doses should be rapidly evaluated and the possible need to modify doses or propose combination therapies should be considered.


Subject(s)
COVID-19 , Viral Envelope Proteins , Antibodies, Monoclonal , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing , Antibodies, Viral/therapeutic use , COVID-19/drug therapy , Humans , Membrane Glycoproteins , Neutralization Tests , SARS-CoV-2 , Spike Glycoprotein, Coronavirus
5.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-329966

ABSTRACT

The replacement of the Omicron BA.1 variant of SARS-CoV-2 by the BA.2 sub lineage, which has a different set of mutations in the spike glycoprotein, alters the spectrum of activity of therapeutic antibodies. In this study, we compared the neutralising power of monoclonal antibodies against the Omicron BA.1 and BA.2 variants, with an ancestral strain (D614G) and a Delta variant as reference. Sotrovimab is less active against BA.2 than against BA.1 (fold change reduction ~1,5). Within the Evusheld/ AZD744 cocktail, Cilgavimab is more active against BA.2 than against BA.1 (fold change increase ~32), whilst activity of Tixagevimab remains very low. In total, the activity of Evusheld is significantly improved (fold change increase ~10 compared to BA.1).

6.
Commun Biol ; 5(1): 225, 2022 03 10.
Article in English | MEDLINE | ID: covidwho-1740485

ABSTRACT

Late 2020, SARS-CoV-2 Alpha variant emerged in United Kingdom and gradually replaced G614 strains initially involved in the global spread of the pandemic. In this study, we use a Syrian hamster model to compare a clinical strain of Alpha variant with an ancestral G614 strain. The Alpha variant succeed to infect animals and to induce a pathology that mimics COVID-19. However, both strains replicate to almost the same level and induced a comparable disease and immune response. A slight fitness advantage is noted for the G614 strain during competition and transmission experiments. These data do not corroborate the epidemiological situation observed during the first half of 2021 in humans nor reports that showed a more rapid replication of Alpha variant in human reconstituted bronchial epithelium. This study highlights the need to combine data from different laboratories using various animal models to decipher the biological properties of newly emerging SARS-CoV-2 variants.


Subject(s)
COVID-19 , Disease Models, Animal , Mesocricetus , SARS-CoV-2/physiology , Animals , Antibodies, Neutralizing/blood , COVID-19/blood , COVID-19/immunology , COVID-19/virology , Cytokines/genetics , Female , Gastrointestinal Tract/virology , Genome, Viral , Lung/virology , Nasal Lavage Fluid/virology , SARS-CoV-2/genetics , Virus Replication
7.
EMBO Rep ; 23(5): e53820, 2022 05 04.
Article in English | MEDLINE | ID: covidwho-1726972

ABSTRACT

Engineering recombinant viruses is a pre-eminent tool for deciphering the biology of emerging viral pathogens such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the large size of coronavirus genomes renders the current reverse genetics methods challenging. Here, we describe a simple method based on "infectious subgenomic amplicons" (ISA) technology to generate recombinant infectious coronaviruses with no need for reconstruction of the complete genomic cDNA and apply this method to SARS-CoV-2 and also to the feline enteric coronavirus. In both cases we rescue wild-type viruses with biological characteristics similar to original strains. Specific mutations and fluorescent red reporter genes can be readily incorporated into the SARS-CoV-2 genome enabling the generation of a genomic variants and fluorescent reporter strains for in vivo experiments, serological diagnosis, and antiviral assays. The swiftness and simplicity of the ISA method has the potential to facilitate the advance of coronavirus reverse genetics studies, to explore the molecular biological properties of the SARS-CoV-2 variants, and to accelerate the development of effective therapeutic reagents.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antiviral Agents , COVID-19/genetics , Cats , Reverse Genetics , SARS-CoV-2/genetics
8.
Viruses ; 12(6)2020 06 08.
Article in English | MEDLINE | ID: covidwho-1726020

ABSTRACT

Clinical samples collected in coronavirus disease 19 (COVID-19), patients are commonly manipulated in biosafety level 2 laboratories for molecular diagnostic purposes. Here, we tested French norm NF-EN-14476+A2 derived from European standard EN-14885 to assess the risk of manipulating infectious viruses prior to RNA extraction. SARS-CoV-2 cell-culture supernatant and nasopharyngeal samples (virus-spiked samples and clinical samples collected in COVID-19 patients) were used to measure the reduction of infectivity after 10 minute contact with lysis buffer containing various detergents and chaotropic agents. A total of thirteen protocols were evaluated. Two commercially available formulations showed the ability to reduce infectivity by at least 6 log 10, whereas others proved less effective.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/virology , Pneumonia, Viral/virology , Virus Inactivation/drug effects , Animals , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , Betacoronavirus/physiology , COVID-19 , Cell Culture Techniques/methods , Chlorocebus aethiops , Containment of Biohazards/methods , Containment of Biohazards/standards , Humans , Nasopharynx/virology , Pandemics , RNA, Viral/isolation & purification , SARS-CoV-2 , Specimen Handling/methods , Vero Cells , Viral Load/methods
9.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-329017

ABSTRACT

The efficacy of pre-exposure prophylaxis by the Tixagevimab/Cilgavimab cocktail (AZD7442) was evaluated in hamsters against a clinical BA.1 strain of SARS-CoV-2 variant Omicron. AZD7442 retains inhibitory activity against Omicron despite a substantial loss of efficacy. We estimate that Omicron virus requires about 20-times more antibodies in plasma than the ancestral B.1 strain (G614) virus to achieve a similar drug efficacy in reducing lung infectious titers.

10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-316871

ABSTRACT

Engineering recombinant viruses is capital for deciphering the biology of emerging viral pathogens such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the large size of coronaviruses genome makes reverse genetics methods challenging.Here we describe a simple method based on “infectious subgenomic amplicons” (ISA) technology to generate recombinant infectious coronaviruses with no need for reconstructing a full genomic cDNA. The method was applied to the SARS-CoV-2 and the feline enteric coronavirus, and allowed to rescue wild-type viruses with biological characteristics closely similar to original strains. Mutations and fluorescent red reporter gene were rapidly incorporated into the SARS-CoV-2 genome allowing the generation of a genomic variant and a fluorescent reporter strains which were studied during in vivo experiments, serological diagnosis and antiviral assays. The swiftness and simplicity of the ISA method has the potential to facilitate the advance of coronavirus reverse genetics studies and to explore biological properties of SARS-CoV-2 variants or accelerating the development of therapeutic measures.

11.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-311331

ABSTRACT

Non-human primates infected with SARS-CoV-2 exhibit mild clinical signs. Here we used a mathematical model to characterize in detail the viral dynamics in 31 cynomolgus macaques infected with 10 6 pfu of SARS-CoV-2 for which nasopharyngeal and tracheal viral load were frequently assessed. We identified that infected cells had a large daily viral production (>10 4 virus) and a within-host reproductive basic number of 6 and 4 in nasopharyngeal and tracheal compartment, respectively. After peak viral load, infected cells were rapidly cleared with a half-life of 9 hours, with no significant association between cytokine elevation and clearance. Translating our model to the context of human-to-human infection, human mild infection may be characterized by a peak occurring 4 days after infection, a viral shedding of ~11 days and a generation time of 4 days. These results improve the understanding of SARS-CoV-2 viral replication and better understand the infection to SARS-CoV-2 in humans.

12.
PLoS One ; 16(12): e0260958, 2021.
Article in English | MEDLINE | ID: covidwho-1546973

ABSTRACT

SARS-CoV-2 variants are emerging with potential increased transmissibility highlighting the great unmet medical need for new therapies. Niclosamide is a potent anti-SARS-CoV-2 agent that has advanced in clinical development. We validate the potent antiviral efficacy of niclosamide in a SARS-CoV-2 human airway model. Furthermore, niclosamide remains its potency against the D614G, Alpha (B.1.1.7), Beta (B.1.351), and Delta (B.1.617.2) variants. Our data further support the potent anti-SARS-CoV-2 properties of niclosamide and highlights its great potential as a therapeutic agent for COVID-19.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , Niclosamide/therapeutic use , SARS-CoV-2/drug effects , Animals , Caco-2 Cells , Chlorocebus aethiops , Humans , Inhibitory Concentration 50 , Respiratory Mucosa/virology , Vero Cells
13.
Antiviral Res ; 197: 105212, 2022 01.
Article in English | MEDLINE | ID: covidwho-1530602

ABSTRACT

Drug repositioning has been used extensively since the beginning of the COVID-19 pandemic in an attempt to identify antiviral molecules for use in human therapeutics. Hydroxychloroquine and azithromycin have shown inhibitory activity against SARS-CoV-2 replication in different cell lines. Based on such in vitro data and despite the weakness of preclinical assessment, many clinical trials were set up using these molecules. In the present study, we show that hydroxychloroquine and azithromycin alone or combined does not block SARS-CoV-2 replication in human bronchial airway epithelia. When tested in a Syrian hamster model, hydroxychloroquine and azithromycin administrated alone or combined displayed no significant effect on viral replication, clinical course of the disease and lung impairments, even at high doses. Hydroxychloroquine quantification in lung tissues confirmed strong exposure to the drug, above in vitro inhibitory concentrations. Overall, this study does not support the use of hydroxychloroquine and azithromycin as antiviral drugs for the treatment of SARS-CoV-2 infections.


Subject(s)
Anti-Infective Agents/pharmacology , Azithromycin/pharmacology , COVID-19/drug therapy , Hydroxychloroquine/pharmacology , SARS-CoV-2/drug effects , Animals , Anti-Infective Agents/administration & dosage , Anti-Infective Agents/therapeutic use , Azithromycin/administration & dosage , Azithromycin/pharmacokinetics , Azithromycin/therapeutic use , Bronchi/cytology , Bronchi/virology , Chlorocebus aethiops , Cricetinae , Disease Models, Animal , Drug Therapy, Combination , Female , Humans , Hydroxychloroquine/administration & dosage , Hydroxychloroquine/therapeutic use , Lung/pathology , Mesocricetus , Middle Aged , Plasma/virology , Real-Time Polymerase Chain Reaction , Vero Cells
14.
Viruses ; 13(9)2021 09 12.
Article in English | MEDLINE | ID: covidwho-1411086

ABSTRACT

Our therapeutic arsenal against viruses is very limited and the current pandemic of SARS-CoV-2 highlights the critical need for effective antivirals against emerging coronaviruses. Cellular assays allowing a precise quantification of viral replication in high-throughput experimental settings are essential to the screening of chemical libraries and the selection of best antiviral chemical structures. To develop a reporting system for SARS-CoV-2 infection, we generated cell lines expressing a firefly luciferase maintained in an inactive form by a consensus cleavage site for the viral protease 3CLPro of coronaviruses, so that the luminescent biosensor is turned on upon 3CLPro expression or SARS-CoV-2 infection. This cellular assay was used to screen a metabolism-oriented library of 492 compounds to identify metabolic vulnerabilities of coronaviruses for developing innovative therapeutic strategies. In agreement with recent reports, inhibitors of pyrimidine biosynthesis were found to prevent SARS-CoV-2 replication. Among the top hits, we also identified the NADPH oxidase (NOX) inhibitor Setanaxib. The anti-SARS-CoV-2 activity of Setanaxib was further confirmed using ACE2-expressing human pulmonary cells Beas2B as well as human primary nasal epithelial cells. Altogether, these results validate our cell-based functional assay and the interest of screening libraries of different origins to identify inhibitors of SARS-CoV-2 for drug repurposing or development.


Subject(s)
Antiviral Agents/isolation & purification , Biosensing Techniques/methods , Coronavirus 3C Proteases/metabolism , SARS-CoV-2/physiology , Virus Replication , Animals , Antiviral Agents/pharmacology , Cell Line , Chlorocebus aethiops , Drug Discovery , Drug Evaluation, Preclinical , Enzyme Activation , HEK293 Cells , Humans , Luciferases, Firefly/metabolism , Nasal Mucosa/virology , Pyrazolones/pharmacology , Pyridones/pharmacology , SARS-CoV-2/metabolism , Vero Cells , Virus Internalization/drug effects , Virus Replication/drug effects
15.
Nat Commun ; 12(1): 1735, 2021 03 19.
Article in English | MEDLINE | ID: covidwho-1387332

ABSTRACT

Despite no or limited pre-clinical evidence, repurposed drugs are massively evaluated in clinical trials to palliate the lack of antiviral molecules against SARS-CoV-2. Here we use a Syrian hamster model to assess the antiviral efficacy of favipiravir, understand its mechanism of action and determine its pharmacokinetics. When treatment is initiated before or simultaneously to infection, favipiravir has a strong dose effect, leading to reduction of infectious titers in lungs and clinical alleviation of the disease. Antiviral effect of favipiravir correlates with incorporation of a large number of mutations into viral genomes and decrease of viral infectivity. Antiviral efficacy is achieved with plasma drug exposure comparable with those previously found during human clinical trials. Notably, the highest dose of favipiravir tested is associated with signs of toxicity in animals. Thereby, pharmacokinetic and tolerance studies are required to determine whether similar effects can be safely achieved in humans.


Subject(s)
Amides/pharmacology , Antiviral Agents/pharmacology , COVID-19/drug therapy , Pyrazines/pharmacology , SARS-CoV-2/drug effects , Animals , COVID-19/virology , Chlorocebus aethiops , Cricetinae , Disease Models, Animal , Female , Genome, Viral , Lung/virology , Mesocricetus , SARS-CoV-2/genetics , Vero Cells , Viral Load/drug effects
16.
Antiviral Res ; 193: 105137, 2021 09.
Article in English | MEDLINE | ID: covidwho-1306846

ABSTRACT

Following the emergence of SARS-CoV-2, the search for an effective and rapidly available treatment was initiated worldwide based on repurposing of available drugs. Previous reports described the antiviral activity of certain tyrosine kinase inhibitors (TKIs) targeting the Abelson kinase 2 against pathogenic coronaviruses. Imatinib, one of them, has more than twenty years of safe utilization for the treatment of hematological malignancies. In this context, Imatinib was rapidly evaluated in clinical trials against Covid-19. Here, we present the pre-clinical evaluation of imatinib in multiple models. Our results indicated that imatinib and another TKI, the masitinib, exhibit an antiviral activity in VeroE6 cells. However, imatinib was inactive in a reconstructed bronchial human airway epithelium model. In vivo, imatinib therapy failed to impair SARS-CoV-2 replication in a golden Syrian hamster model despite high concentrations in plasma and in the lung. Overall, these results do not support the use of imatinib and similar TKIs as antivirals in the treatment of Covid-19.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Imatinib Mesylate/pharmacology , SARS-CoV-2/drug effects , Animals , COVID-19/epidemiology , COVID-19/virology , Cell Line , Chlorocebus aethiops , Drug Evaluation, Preclinical , Drug Repositioning , Enzyme Inhibitors/pharmacology , Epithelium , Female , Humans , Lung/pathology , Male , Mesocricetus , Vero Cells , Virus Replication/drug effects
17.
mBio ; 12(4): e0085021, 2021 08 31.
Article in English | MEDLINE | ID: covidwho-1297961

ABSTRACT

Since its emergence in 2019, circulating populations of the new coronavirus (CoV) continuously acquired genetic diversity. At the end of 2020, a variant named 20I/501Y.V1 (lineage B.1.1.7) emerged and replaced other circulating strains in several regions. This phenomenon has been poorly associated with biological evidence that this variant and the original strain exhibit different phenotypic characteristics. Here, we analyze the replication ability of this new variant in different cellular models using for comparison an ancestral D614G European strain (lineage B1). Results from comparative replication kinetics experiments in vitro and in a human reconstituted bronchial epithelium showed no difference. However, when both viruses were put in competition in human reconstituted bronchial epithelium, the 20I/501Y.V1 variant outcompeted the ancestral strain. All together, these findings demonstrate that this new variant replicates more efficiently and may contribute to a better understanding of the progressive replacement of circulating strains by the severe acute respiratory CoV-2 (SARS-CoV-2) 20I/501Y.V1 variant. IMPORTANCE The emergence of several SARS-CoV-2 variants raised numerous questions concerning the future course of the pandemic. We are currently observing a replacement of the circulating viruses by the variant from the United Kingdom known as 20I/501Y.V1, from the B.1.1.7 lineage, but there is little biological evidence that this new variant exhibits a different phenotype. In the present study, we used different cellular models to assess the replication ability of the 20I/501Y.V1 variant. Our results showed that this variant replicates more efficiently in human reconstituted bronchial epithelium, which may explain why it spreads so rapidly in human populations.


Subject(s)
COVID-19/transmission , Genetic Fitness/genetics , SARS-CoV-2/growth & development , SARS-CoV-2/genetics , Virus Replication/genetics , Animals , COVID-19/pathology , Caco-2 Cells , Cell Line , Chlorocebus aethiops , Humans , Respiratory Mucosa/virology , Vero Cells , Viral Load
18.
PLoS Comput Biol ; 17(3): e1008785, 2021 03.
Article in English | MEDLINE | ID: covidwho-1181165

ABSTRACT

Non-human primates infected with SARS-CoV-2 exhibit mild clinical signs. Here we used a mathematical model to characterize in detail the viral dynamics in 31 cynomolgus macaques for which nasopharyngeal and tracheal viral load were frequently assessed. We identified that infected cells had a large burst size (>104 virus) and a within-host reproductive basic number of approximately 6 and 4 in nasopharyngeal and tracheal compartment, respectively. After peak viral load, infected cells were rapidly lost with a half-life of 9 hours, with no significant association between cytokine elevation and clearance, leading to a median time to viral clearance of 10 days, consistent with observations in mild human infections. Given these parameter estimates, we predict that a prophylactic treatment blocking 90% of viral production or viral infection could prevent viral growth. In conclusion, our results provide estimates of SARS-CoV-2 viral kinetic parameters in an experimental model of mild infection and they provide means to assess the efficacy of future antiviral treatments.


Subject(s)
COVID-19/virology , Macaca fascicularis/virology , SARS-CoV-2/physiology , Animals , Antiviral Agents/pharmacology , Basic Reproduction Number , COVID-19/blood , COVID-19/prevention & control , Cytokines/blood , Disease Models, Animal , Nasopharynx/virology , SARS-CoV-2/drug effects , Trachea/virology , Viral Load , Virus Replication/drug effects
19.
Molecules ; 26(5)2021 Mar 09.
Article in English | MEDLINE | ID: covidwho-1143539

ABSTRACT

A series of hitherto unknown (1,4-disubstituted-1,2,3-triazol)-(E)-2-methyl-but-2-enyl nucleosides phosphonate prodrugs bearing 4-substituted-1,2,3-triazoles were prepared in a straight approach through an olefin acyclic cross metathesis as the key synthetic step. All novel compounds were evaluated for their antiviral activities against HBV, HIV and SARS-CoV-2. Among these molecules, only compound 15j, a hexadecyloxypropyl (HDP)/(isopropyloxycarbonyl-oxymethyl)-ester (POC) prodrug, showed activity against HBV in Huh7 cell cultures with 62% inhibition at 10 µM, without significant cytotoxicity (IC50 = 66.4 µM in HepG2 cells, IC50 = 43.1 µM in HepG2 cells) at 10 µM.


Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacology , Azo Compounds/chemistry , Nucleosides/chemistry , Organophosphonates/chemistry , Prodrugs/chemical synthesis , Prodrugs/pharmacology , Alkenes/chemistry , Animals , Cell Line, Tumor , Chlorocebus aethiops , HIV-1/drug effects , Hepatitis B virus/drug effects , Humans , Magnetic Resonance Spectroscopy , Methylation , SARS-CoV-2/drug effects , Structure-Activity Relationship , Triazoles/chemistry , Vero Cells
20.
Nat Commun ; 11(1): 4682, 2020 09 17.
Article in English | MEDLINE | ID: covidwho-779999

ABSTRACT

The ongoing Corona Virus Disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has emphasized the urgent need for antiviral therapeutics. The viral RNA-dependent-RNA-polymerase (RdRp) is a promising target with polymerase inhibitors successfully used for the treatment of several viral diseases. We demonstrate here that Favipiravir predominantly exerts an antiviral effect through lethal mutagenesis. The SARS-CoV RdRp complex is at least 10-fold more active than any other viral RdRp known. It possesses both unusually high nucleotide incorporation rates and high-error rates allowing facile insertion of Favipiravir into viral RNA, provoking C-to-U and G-to-A transitions in the already low cytosine content SARS-CoV-2 genome. The coronavirus RdRp complex represents an Achilles heel for SARS-CoV, supporting nucleoside analogues as promising candidates for the treatment of COVID-19.


Subject(s)
Amides/pharmacology , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Betacoronavirus/genetics , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Pyrazines/pharmacology , Amides/pharmacokinetics , Animals , Antiviral Agents/pharmacokinetics , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/virology , Coronavirus RNA-Dependent RNA Polymerase , Models, Molecular , Mutagenesis/drug effects , Pandemics , Pneumonia, Viral/virology , Pyrazines/pharmacokinetics , RNA, Viral/genetics , RNA, Viral/metabolism , RNA-Dependent RNA Polymerase/chemistry , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2 , Sequence Analysis , Vero Cells , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects
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