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1.
EBioMedicine ; 82: 104148, 2022 Jul 11.
Article in English | MEDLINE | ID: covidwho-1926364

ABSTRACT

BACKGROUND: To address the emergence of SARS-CoV-2, multiple clinical trials in humans were rapidly started, including those involving an oral treatment by nitazoxanide, despite no or limited pre-clinical evidence of antiviral efficacy. METHODS: In this work, we present a complete pre-clinical evaluation of the antiviral activity of nitazoxanide against SARS-CoV-2. FINDINGS: First, we confirmed the in vitro efficacy of nitazoxanide and tizoxanide (its active metabolite) against SARS-CoV-2. Then, we demonstrated nitazoxanide activity in a reconstructed bronchial human airway epithelium model. In a SARS-CoV-2 virus challenge model in hamsters, oral and intranasal treatment with nitazoxanide failed to impair viral replication in commonly affected organs. We hypothesized that this could be due to insufficient diffusion of the drug into organs of interest. Indeed, our pharmacokinetic study confirmed that concentrations of tizoxanide in organs of interest were always below the in vitro EC50. INTERPRETATION: These preclinical results suggest, if directly applicable to humans, that the standard formulation and dosage of nitazoxanide is not effective in providing antiviral therapy for Covid-19. FUNDING: This work was supported by the Fondation de France "call FLASH COVID-19", project TAMAC, by "Institut national de la santé et de la recherche médicale" through the REACTing (REsearch and ACTion targeting emerging infectious diseases), by REACTING/ANRS MIE under the agreement No. 21180 ('Activité des molécules antivirales dans le modèle hamster'), by European Virus Archive Global (EVA 213 GLOBAL) funded by the European Union's Horizon 2020 research and innovation program under grant agreement No. 871029 and DNDi under support by the Wellcome Trust Grant ref: 222489/Z/21/Z through the COVID-19 Therapeutics Accelerator".

2.
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
3.
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
4.
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.

5.
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.

6.
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
7.
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
8.
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
9.
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
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