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1.
Nature ; 604(7904): 134-140, 2022 04.
Article in English | MEDLINE | ID: covidwho-1671590

ABSTRACT

The SARS-CoV-2 virus has infected more than 261 million people and has led to more than 5 million deaths in the past year and a half1 ( https://www.who.org/ ). Individuals with SARS-CoV-2 infection typically develop mild-to-severe flu-like symptoms, whereas infection of a subset of individuals leads to severe-to-fatal clinical outcomes2. Although vaccines have been rapidly developed to combat SARS-CoV-2, there has been a dearth of antiviral therapeutics. There is an urgent need for therapeutics, which has been amplified by the emerging threats of variants that may evade vaccines. Large-scale efforts are underway to identify antiviral drugs. Here we screened approximately 18,000 drugs for antiviral activity using live virus infection in human respiratory cells and validated 122 drugs with antiviral activity and selectivity against SARS-CoV-2. Among these candidates are 16 nucleoside analogues, the largest category of clinically used antivirals. This included the antivirals remdesivir and molnupiravir, which have been approved for use in COVID-19. RNA viruses rely on a high supply of nucleoside triphosphates from the host to efficiently replicate, and we identified a panel of host nucleoside biosynthesis inhibitors as antiviral. Moreover, we found that combining pyrimidine biosynthesis inhibitors with antiviral nucleoside analogues synergistically inhibits SARS-CoV-2 infection in vitro and in vivo against emerging strains of SARS-CoV-2, suggesting a clinical path forward.


Subject(s)
Antiviral Agents , Drug Evaluation, Preclinical , Nucleosides , Pyrimidines , SARS-CoV-2 , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/virology , Cell Line , Cytidine/analogs & derivatives , Humans , Hydroxylamines , Nucleosides/analogs & derivatives , Nucleosides/pharmacology , Pyrimidines/pharmacology , SARS-CoV-2/drug effects
2.
Clin Chem ; 68(1): 230-239, 2021 12 30.
Article in English | MEDLINE | ID: covidwho-1354284

ABSTRACT

BACKGROUND: High-sensitivity severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen assays are desirable to mitigate false negative results. Limited data are available to quantify and track SARS-CoV-2 antigen burden in respiratory samples from different populations. METHODS: We developed the Microbubbling SARS-CoV-2 Antigen Assay (MSAA) with smartphone readout, with a limit of detection of 0.5 pg/mL (10.6 fmol/L) nucleocapsid antigen or 4000 copies/mL inactivated SARS-CoV-2 virus in nasopharyngeal (NP) swabs. We developed a computer vision and machine learning-based automatic microbubble image classifier to accurately identify positives and negatives and quantified and tracked antigen dynamics in intensive care unit coronavirus disease 2019 (COVID-19) inpatients and immunocompromised COVID-19 patients. RESULTS: Compared to qualitative reverse transcription-polymerase chain reaction methods, the MSAA demonstrated a positive percentage agreement of 97% (95% CI 92%-99%) and a negative percentage agreement of 97% (95% CI 94%-100%) in a clinical validation study with 372 residual clinical NP swabs. In immunocompetent individuals, the antigen positivity rate in swabs decreased as days-after-symptom-onset increased, despite persistent nucleic acid positivity. Antigen was detected for longer and variable periods of time in immunocompromised patients with hematologic malignancies. Total microbubble volume, a quantitative marker of antigen burden, correlated inversely with cycle threshold values and days-after-symptom-onset. Viral sequence variations were detected in patients with long duration of high antigen burden. CONCLUSIONS: The MSAA enables sensitive and specific detection of acute infections and quantification and tracking of antigen burden and may serve as a screening method in longitudinal studies to identify patients who are likely experiencing active rounds of ongoing replication and warrant close viral sequence monitoring.


Subject(s)
Antigens, Viral/analysis , COVID-19 Testing/methods , COVID-19 , Smartphone , COVID-19/diagnosis , Humans , Machine Learning , SARS-CoV-2 , Sensitivity and Specificity
3.
Sci Immunol ; 6(59)2021 05 18.
Article in English | MEDLINE | ID: covidwho-1234281

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic, resulting millions of infections and deaths with few effective interventions available. Here, we demonstrate that SARS-CoV-2 evades interferon (IFN) activation in respiratory epithelial cells, resulting in a delayed response in bystander cells. Since pretreatment with IFNs can block viral infection, we reasoned that pharmacological activation of innate immune pathways could control SARS-CoV-2 infection. To identify potent antiviral innate immune agonists, we screened a panel of 75 microbial ligands that activate diverse signaling pathways and identified cyclic dinucleotides (CDNs), canonical STING agonists, as antiviral. Since CDNs have poor bioavailability, we tested the small molecule STING agonist diABZI, and found that it potently inhibits SARS-CoV-2 infection of diverse strains including variants of concern (B.1.351) by transiently stimulating IFN signaling. Importantly, diABZI restricts viral replication in primary human bronchial epithelial cells and in mice in vivo. Our study provides evidence that activation of STING may represent a promising therapeutic strategy to control SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , Benzimidazoles/pharmacology , COVID-19/prevention & control , Interferons/immunology , Membrane Proteins/agonists , Animals , Cell Line , Chlorocebus aethiops , Enzyme Activation/drug effects , Epithelial Cells/virology , Humans , Immune Evasion/immunology , Immunity, Innate/drug effects , Immunity, Innate/immunology , Mice , Mice, Inbred C57BL , Mice, Transgenic , SARS-CoV-2/growth & development , SARS-CoV-2/immunology , Vero Cells , Virus Replication/drug effects
4.
Cell Rep ; 35(1): 108959, 2021 04 06.
Article in English | MEDLINE | ID: covidwho-1163484

ABSTRACT

There is an urgent need for antivirals to treat the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To identify new candidates, we screen a repurposing library of ∼3,000 drugs. Screening in Vero cells finds few antivirals, while screening in human Huh7.5 cells validates 23 diverse antiviral drugs. Extending our studies to lung epithelial cells, we find 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 find nine drugs are antiviral in respiratory cells, seven of which have been used in humans, and three are US Food and Drug Administration (FDA) approved, including cyclosporine. We find that the antiviral activity of cyclosporine is targeting Cyclophilin rather than calcineurin, revealing essential host targets that have the potential for rapid clinical implementation.


Subject(s)
COVID-19/drug therapy , Cyclosporine/pharmacology , Drug Repositioning , Epithelial Cells/metabolism , Lung/metabolism , SARS-CoV-2/metabolism , Animals , COVID-19/metabolism , COVID-19/pathology , Chlorocebus aethiops , Epithelial Cells/pathology , Epithelial Cells/virology , Humans , Lung/pathology , Lung/virology , Serine Endopeptidases/metabolism , United States , United States Food and Drug Administration , Vero Cells
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