Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 84
Filter
1.
Molecules ; 27(5)2022 Mar 07.
Article in English | MEDLINE | ID: covidwho-1732132

ABSTRACT

The COVID-19 pandemic has led to the search for new molecules with antiviral activity against SARS-CoV-2. The entry of the virus into the cell is one of the main targets for inhibiting SARS-CoV-2 infection. Natural products are an important source of new therapeutic alternatives against diseases. Pseudotyped viruses allow the study of SARS-CoV-2 viral entry inhibitors, and due to their simplicity, they allow the screening of a large number of antiviral candidates in Biosafety Level 2 facilities. We used pseudotyped HIV-1 with the D614G SARS-CoV-2 spike glycoprotein to test its ability to infect ACE2-expressing HEK 293T cells in the presence of diverse natural products, including 21 plant extracts, 7 essential oils, and 13 compounds from plants and fungi. The 50% cytotoxic concentration (CC50) was evaluated using the resazurin method. From these analyses, we determined the inhibitory activity of the extract of Stachytarpheta cayennensis, which had a half-maximal inhibitory concentration (IC50) of 91.65 µg/mL, a CC50 of 693.5 µg/mL, and a selectivity index (SI) of 7.57, indicating its potential use as an inhibitor of SARS-CoV-2 entry. Moreover, our work indicates the usefulness of the pseudotyped-virus system in the screening of SARS-CoV-2 entry inhibitors.


Subject(s)
Antiviral Agents/pharmacology , Biological Products/chemistry , Virus Internalization/drug effects , Actinobacteria/chemistry , Actinobacteria/metabolism , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Biological Products/metabolism , Biological Products/pharmacology , Biological Products/therapeutic use , COVID-19/drug therapy , COVID-19/virology , HEK293 Cells , High-Throughput Screening Assays/methods , Humans , Oils, Volatile/chemistry , Oils, Volatile/pharmacology , Oils, Volatile/therapeutic use , Plant Extracts/chemistry , Plant Extracts/metabolism , Plant Extracts/pharmacology , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/metabolism
2.
Chem Pharm Bull (Tokyo) ; 70(3): 199-201, 2022 Mar 01.
Article in English | MEDLINE | ID: covidwho-1714684

ABSTRACT

MS is a powerful methodology for chemical screening to directly quantify substrates and products of enzymes, but its low throughput has been an issue. Recently, an acoustic liquid-handling apparatus (Echo®) used for rapid nano-dispensing has been coupled to a high-sensitivity mass spectrometer to create the Echo® MS system, and we applied this system to screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 3CL protease inhibitors. Primary screening of 32033 chemical samples was completed in 12 h. Among the hits showing selective, dose-dependent 3CL-inhibitory activity, 8 compounds showed antiviral activity in cell-based assay.


Subject(s)
COVID-19 , Protease Inhibitors , Acoustics , COVID-19/drug therapy , High-Throughput Screening Assays/methods , Humans , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , SARS-CoV-2
3.
Front Endocrinol (Lausanne) ; 12: 802447, 2021.
Article in English | MEDLINE | ID: covidwho-1699427

ABSTRACT

Coronavirus disease 2019 (COVID-19) is a serious epidemic, characterized by potential mutation and can bring about poor vaccine efficiency. It is evidenced that patients with malignancies, including prostate cancer (PC), may be highly vulnerable to the SARS-CoV-2 infection. Currently, there are no existing drugs that can cure PC and COVID-19. Luteolin can potentially be employed for COVID-19 treatment and serve as a potent anticancer agent. Our present study was conducted to discover the possible drug target and curative mechanism of luteolin to serve as treatment for PC and COVID-19. The differential gene expression of PC cases was determined via RNA sequencing. The application of network pharmacology and molecular docking aimed to exhibit the drug targets and pharmacological mechanisms of luteolin. In this study, we found the top 20 up- and downregulated gene expressions in PC patients. Enrichment data demonstrated anti-inflammatory effects, where improvement of metabolism and enhancement of immunity were the main functions and mechanism of luteolin in treating PC and COVID-19, characterized by associated signaling pathways. Additional core drug targets, including MPO and FOS genes, were computationally identified accordingly. In conclusion, luteolin may be a promising treatment for PC and COVID-19 based on bioinformatics findings, prior to future clinical validation and application.


Subject(s)
COVID-19/drug therapy , Drug Discovery/methods , Luteolin/therapeutic use , Prostatic Neoplasms/drug therapy , COVID-19/pathology , Computational Biology/methods , High-Throughput Screening Assays/methods , Humans , Luteolin/pharmacology , Male , Metabolic Networks and Pathways/drug effects , Models, Molecular , Molecular Docking Simulation , Molecular Targeted Therapy/methods , Prostatic Neoplasms/pathology , Protein Interaction Maps/drug effects , Protein Interaction Maps/physiology , SARS-CoV-2/drug effects , SARS-CoV-2/physiology
4.
Bioprocess Biosyst Eng ; 45(3): 503-514, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1627214

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had severe consequences for health and the global economy. To control the transmission, there is an urgent demand for early diagnosis and treatment in the general population. In the present study, an automatic system for SARS-CoV-2 diagnosis is designed and built to deliver high specification, high sensitivity, and high throughput with minimal workforce involvement. The system, set up with cross-priming amplification (CPA) rather than conventional reverse transcription-polymerase chain reaction (RT-PCR), was evaluated using more than 1000 real-world samples for direct comparison. This fully automated robotic system performed SARS-CoV-2 nucleic acid-based diagnosis with 192 samples in under 180 min at 100 copies per reaction in a "specimen in data out" manner. This throughput translates to a daily screening capacity of 800-1000 in an assembly-line manner with limited workforce involvement. The sensitivity of this device could be further improved using a CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-based assay, which opens the door to mixed samples, potentially include SARS-CoV-2 variants screening in extensively scaled testing for fighting COVID-19.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , SARS-CoV-2 , Algorithms , Biomedical Engineering/instrumentation , Biomedical Engineering/methods , Biomedical Engineering/statistics & numerical data , COVID-19/epidemiology , COVID-19/virology , COVID-19 Nucleic Acid Testing/instrumentation , COVID-19 Nucleic Acid Testing/statistics & numerical data , Clustered Regularly Interspaced Short Palindromic Repeats , Equipment Design , High-Throughput Screening Assays/instrumentation , High-Throughput Screening Assays/methods , High-Throughput Screening Assays/statistics & numerical data , Humans , Nucleic Acid Amplification Techniques/instrumentation , Nucleic Acid Amplification Techniques/methods , Nucleic Acid Amplification Techniques/statistics & numerical data , Pandemics , Robotics/instrumentation , Robotics/methods , Robotics/statistics & numerical data , SARS-CoV-2/genetics , Sensitivity and Specificity , Systems Analysis
5.
Biochem Biophys Res Commun ; 591: 118-123, 2022 02 05.
Article in English | MEDLINE | ID: covidwho-1588231

ABSTRACT

3-chyomotrypsin like protease (3CLpro) has been considered as a promising target for developing anti-SARS-CoV-2 drugs. Herein, about 6000 compounds were analyzed by high-throughput screening using enzyme activity model, and Merbromin, an antibacterial agent, was identified as a potent inhibitor of 3CLpro. Merbromin strongly inhibited the proteolytic activity of 3CLpro but not the other three proteases Proteinase K, Trypsin and Papain. Michaelis-Menten kinetic analysis showed that Merbromin was a mixed-type inhibitor of 3CLpro, due to its ability of increasing the KM and decreasing the Kcat of 3CLpro. The binding assays and molecular docking suggested that 3CLpro possessed two binding sites for Merbromin. Consistently, Merbromin showed a weak binding to the other three proteases. Together, these findings demonstrated that Merbromin is a selective inhibitor of 3CLpro and provided a scaffold to design effective inhibitors of SARS-CoV-2.


Subject(s)
Coronavirus 3C Proteases/antagonists & inhibitors , Merbromin/pharmacology , Molecular Docking Simulation , Protease Inhibitors/pharmacology , SARS-CoV-2/drug effects , Binding Sites , COVID-19/prevention & control , COVID-19/virology , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/metabolism , High-Throughput Screening Assays/methods , Humans , Kinetics , Merbromin/chemistry , Merbromin/metabolism , Models, Molecular , Molecular Structure , Protease Inhibitors/chemistry , Protease Inhibitors/metabolism , Protein Binding , Protein Domains , SARS-CoV-2/enzymology , SARS-CoV-2/physiology , Surface Plasmon Resonance/methods
6.
SLAS Discov ; 27(2): 86-94, 2022 03.
Article in English | MEDLINE | ID: covidwho-1586501

ABSTRACT

Effective small molecule therapies to combat the SARS-CoV-2 infection are still lacking as the COVID-19 pandemic continues globally. High throughput screening assays are needed for lead discovery and optimization of small molecule SARS-CoV-2 inhibitors. In this work, we have applied viral pseudotyping to establish a cell-based SARS-CoV-2 entry assay. Here, the pseudotyped particles (PP) contain SARS-CoV-2 spike in a membrane enveloping both the murine leukemia virus (MLV) gag-pol polyprotein and luciferase reporter RNA. Upon addition of PP to HEK293-ACE2 cells, the SARS-CoV-2 spike protein binds to the ACE2 receptor on the cell surface, resulting in priming by host proteases to trigger endocytosis of these particles, and membrane fusion between the particle envelope and the cell membrane. The internalized luciferase reporter gene is then expressed in cells, resulting in a luminescent readout as a surrogate for spike-mediated entry into cells. This SARS-CoV-2 PP entry assay can be executed in a biosafety level 2 containment lab for high throughput screening. From a collection of 5,158 approved drugs and drug candidates, our screening efforts identified 7 active compounds that inhibited the SARS-CoV-2-S PP entry. Of these seven, six compounds were active against live replicating SARS-CoV-2 virus in a cytopathic effect assay. Our results demonstrated the utility of this assay in the discovery and development of SARS-CoV-2 entry inhibitors as well as the mechanistic study of anti-SARS-CoV-2 compounds. Additionally, particles pseudotyped with spike proteins from SARS-CoV-2 B.1.1.7 and B.1.351 variants were prepared and used to evaluate the therapeutic effects of viral entry inhibitors.


Subject(s)
Antiviral Agents/pharmacology , High-Throughput Screening Assays/methods , SARS-CoV-2/drug effects , Virus Internalization/drug effects , HEK293 Cells , Humans
7.
Emerg Microbes Infect ; 11(1): 250-259, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1585240

ABSTRACT

Testing and vaccination have been major components of the strategy for combating the ongoing COVID-19 pandemic. In this study, we have developed a quantitative anti-SARS-CoV-2 spike (S1) IgG antibody assay using a fingerstick dried blood sample. We evaluated the feasibility of using this high-throughput and quantitative anti-SARS-CoV-2 spike (S1) IgG antibody testing assay in vaccinated individuals. Fingerstick blood samples were collected and analyzed from 137 volunteers before and after receiving the Moderna or Pfizer mRNA vaccine. Anti-SARS-CoV-2 S1 IgG antibody could not be detected within the first 7 days after receiving the first vaccine dose, however, the assay reliably detected antibodies from day 14 onwards. In addition, no anti-SARS-CoV-2 nucleocapsid (N) protein IgG antibody was detected in any of the vaccinated or healthy participants, indicating that the anti-SARS-CoV-2 S1 IgG assay is specific for the mRNA vaccine-induced antibodies. The S1 IgG levels detected in fingerstick samples correlated with the levels found in venous blood plasma samples and with the efficacy of venous blood plasma samples in the plaque reduction neutralization test (PRNT). The assay displayed a limit of quantification (LOQ) of 0.59 µg/mL and was found to be linear in the range of 0.51-1000 µg/mL. Finally, its clinical performance displayed a Positive Percent Agreement (PPA) of 100% (95% CI: 0.89-1.00) and a Negative Percent Agreement (NPA) of 100% (95% CI: 0.93-1.00). In summary, the assay described here represents a sensitive, precise, accurate, and simple method for the quantitative detection and monitoring of post-vaccination anti-SARS-CoV-2 spike IgG responses.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19 Vaccines/immunology , COVID-19/immunology , High-Throughput Screening Assays/methods , Immunoassay/methods , SARS-CoV-2/immunology , Specimen Handling/methods , Antibodies, Viral/blood , Female , Humans , Immunoglobulin G/blood , Male , Spike Glycoprotein, Coronavirus , Vaccination
8.
Int J Mol Sci ; 23(1)2021 Dec 30.
Article in English | MEDLINE | ID: covidwho-1580695

ABSTRACT

Since December 2019, the new SARS-CoV-2-related COVID-19 disease has caused a global pandemic and shut down the public life worldwide. Several proteins have emerged as potential therapeutic targets for drug development, and we sought out to review the commercially available and marketed SARS-CoV-2-targeted libraries ready for high-throughput virtual screening (HTVS). We evaluated the SARS-CoV-2-targeted, protease-inhibitor-focused and protein-protein-interaction-inhibitor-focused libraries to gain a better understanding of how these libraries were designed. The most common were ligand- and structure-based approaches, along with various filtering steps, using molecular descriptors. Often, these methods were combined to obtain the final library. We recognized the abundance of targeted libraries offered and complimented by the inclusion of analytical data; however, serious concerns had to be raised. Namely, vendors lack the information on the library design and the references to the primary literature. Few references to active compounds were also provided when using the ligand-based design and usually only protein classes or a general panel of targets were listed, along with a general reference to the methods, such as molecular docking for the structure-based design. No receptor data, docking protocols or even references to the applied molecular docking software (or other HTVS software), and no pharmacophore or filter design details were given. No detailed functional group or chemical space analyses were reported, and no specific orientation of the libraries toward the design of covalent or noncovalent inhibitors could be observed. All libraries contained pan-assay interference compounds (PAINS), rapid elimination of swill compounds (REOS) and aggregators, as well as focused on the drug-like model, with the majority of compounds possessing their molecular mass around 500 g/mol. These facts do not bode well for the use of the reviewed libraries in drug design and lend themselves to commercial drug companies to focus on and improve.


Subject(s)
Antiviral Agents/chemistry , Drug Design/methods , High-Throughput Screening Assays/methods , Protease Inhibitors/chemistry , Protein Interaction Domains and Motifs , SARS-CoV-2/chemistry , Small Molecule Libraries/chemistry , Databases, Chemical , Humans , Molecular Docking Simulation , Protease Inhibitors/metabolism , SARS-CoV-2/metabolism
9.
ACS Chem Biol ; 17(1): 17-23, 2022 01 21.
Article in English | MEDLINE | ID: covidwho-1569207

ABSTRACT

Macrodomains are a class of conserved ADP-ribosylhydrolases expressed by viruses of pandemic concern, including coronaviruses and alphaviruses. Viral macrodomains are critical for replication and virus-induced pathogenesis; therefore, these enzymes are a promising target for antiviral therapy. However, no potent or selective viral macrodomain inhibitors currently exist, in part due to the lack of a high-throughput assay for this class of enzymes. Here we developed a high-throughput ADP-ribosylhydrolase assay using the SARS-CoV-2 macrodomain Mac1. We performed a pilot screen that identified dasatinib and dihydralazine as ADP-ribosylhydrolase inhibitors. Importantly, dasatinib inhibits SARS-CoV-2 and MERS-CoV Mac1 but not the closest human homologue, MacroD2. Our study demonstrates the feasibility of identifying selective inhibitors based on ADP-ribosylhydrolase activity, paving the way for the screening of large compound libraries to identify improved macrodomain inhibitors and to explore their potential as antiviral therapies for SARS-CoV-2 and future viral threats.


Subject(s)
Antiviral Agents/pharmacology , High-Throughput Screening Assays/methods , N-Glycosyl Hydrolases/antagonists & inhibitors , SARS-CoV-2/drug effects , Dasatinib/pharmacology , Protein Domains , SARS-CoV-2/enzymology
10.
Sci Rep ; 11(1): 23260, 2021 12 01.
Article in English | MEDLINE | ID: covidwho-1545651

ABSTRACT

An overreliance on commercial, kit-based RNA extraction in the molecular diagnoses of infectious disease presents a challenge in the event of supply chain disruptions and can potentially hinder testing capacity in times of need. In this study, we adapted a well-established, robust TRIzol-based RNA extraction protocol into a high-throughput format through miniaturization and automation. The workflow was validated by RT-qPCR assay for SARS-CoV-2 detection to illustrate its scalability without interference to downstream diagnostic sensitivity and accuracy. This semi-automated, kit-free approach offers a versatile alternative to prevailing integrated solid-phase RNA extraction proprietary systems, with the added advantage of improved cost-effectiveness for high volume acquisition of quality RNA whether for use in clinical diagnoses or for diverse molecular applications.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , High-Throughput Screening Assays/methods , RNA, Viral/genetics , RNA, Viral/isolation & purification , Real-Time Polymerase Chain Reaction/methods , SARS-CoV-2/genetics , COVID-19/virology , Humans , Molecular Diagnostic Techniques/methods , RNA, Viral/analysis , ROC Curve
11.
Viruses ; 13(11)2021 11 11.
Article in English | MEDLINE | ID: covidwho-1534242

ABSTRACT

CRISPR/Cas is a powerful tool for studying the role of genes in viral infections. The invention of CRISPR screening technologies has made it possible to untangle complex interactions between the host and viral agents. Moreover, whole-genome and pathway-specific CRISPR screens have facilitated identification of novel drug candidates for treating viral infections. In this review, we highlight recent developments in the fields of CRISPR/Cas with a focus on the use of CRISPR screens for studying viral infections and identifying new candidate genes to aid development of antivirals.


Subject(s)
CRISPR-Cas Systems , Genetic Techniques , Genome-Wide Association Study/methods , High-Throughput Screening Assays/methods , Virus Diseases/genetics , Virus Diseases/virology , Viruses/genetics , Drug Discovery , Host Microbial Interactions , Humans
12.
J Mater Chem B ; 9(42): 8851-8861, 2021 11 03.
Article in English | MEDLINE | ID: covidwho-1526111

ABSTRACT

Nanomaterial-based optical techniques for biomarker detection have garnered tremendous attention from the nanofabrication community due to their high precision and enhanced limit of detection (LoD) features. These nanomaterials are highly responsive to local refractive index (RI) fluctuations, and their RI unit sensitivity can be tuned by varying the chemical composition, geometry, and dimensions of the utilized nanostructures. To improve the sensitivity and LoD values of these nanomaterials, it is common to increase both dimensions and aspect ratios of the fabricated nanostructures. However, limited by the complexity, prolonged duration, and elevated costs of the available nanofabrication techniques, mass production of these nanostructures remains challenging. To address not only high accuracy, but also speed and production effectiveness in these nanostructures' fabrication, our work reports, for the first time, a fast, high-throughput, and cost-effective nanofabrication protocol for routine manufacturing of polymer-based nanostructures with high sensitivity and calculated LoD in the pM range by utilizing anodized aluminum oxide (AAO) membranes as templates. Specifically, our developed platform consists of arrays of nearly uniform polystyrene nanopillars with an average diameter of ∼185 nm and aspect ratio of ∼11. We demonstrate that these nanostructures can be produced at a high speed and a notably low price, and that they can be efficiently applied for biosensing purposes after being coated with aluminum-doped silver (Ag/Al) thin films. Our platform successfully detected very low concentrations of human C-reactive protein (hCRP) and SARS-CoV-2 spike protein biomarkers in human plasma samples with LoDs of 11 and 5 pM, respectively. These results open new opportunities for day-to-day fabrication of high aspect ratio arrays of nanopillars that can be used as a base for nanoplasmonic sensors with competitive LoD values. This, in turn, contributes to the development of point-of-care devices and further improvement of the existing nanofabrication techniques, thereby enriching the fields of pharmacology, clinical analysis, and diagnostics.


Subject(s)
Aluminum Oxide/chemistry , Biomarkers/blood , High-Throughput Screening Assays/methods , Nanostructures/chemistry , Silver/chemistry , Biosensing Techniques , C-Reactive Protein/analysis , COVID-19/diagnosis , COVID-19/virology , Dimethylpolysiloxanes/chemistry , Humans , Limit of Detection , Point-of-Care Systems , Polystyrenes/chemistry , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/blood
13.
Int J Mol Sci ; 22(21)2021 Oct 26.
Article in English | MEDLINE | ID: covidwho-1512374

ABSTRACT

Nucleoside kinases (NKs) are key enzymes involved in the in vivo phosphorylation of nucleoside analogues used as drugs to treat cancer or viral infections. Having different specificities, the characterization of NKs is essential for drug design and nucleotide analogue production in an in vitro enzymatic process. Therefore, a fast and reliable substrate screening method for NKs is of great importance. Here, we report on the validation of a well-known luciferase-based assay for the detection of NK activity in a 96-well plate format. The assay was semi-automated using a liquid handling robot. Good linearity was demonstrated (r² > 0.98) in the range of 0-500 µM ATP, and it was shown that alternative phosphate donors like dATP or CTP were also accepted by the luciferase. The developed high-throughput assay revealed comparable results to HPLC analysis. The assay was exemplarily used for the comparison of the substrate spectra of four NKs using 20 (8 natural, 12 modified) substrates. The screening results correlated well with literature data, and additionally, previously unknown substrates were identified for three of the NKs studied. Our results demonstrate that the developed semi-automated high-throughput assay is suitable to identify best performing NKs for a wide range of substrates.


Subject(s)
Nucleosides/metabolism , Phosphotransferases/metabolism , Adenosine Triphosphate/metabolism , Animals , Drosophila melanogaster/metabolism , Drug Evaluation, Preclinical/methods , High-Throughput Screening Assays/methods , Humans , Luciferases/metabolism , Phosphorylation/physiology , Substrate Specificity
14.
Sci Rep ; 11(1): 20143, 2021 10 11.
Article in English | MEDLINE | ID: covidwho-1462040

ABSTRACT

Rapid, high-throughput diagnostic tests are essential to decelerate the spread of the novel coronavirus disease 2019 (COVID-19) pandemic. While RT-PCR tests performed in centralized laboratories remain the gold standard, rapid point-of-care antigen tests might provide faster results. However, they are associated with markedly reduced sensitivity. Bedside breath gas analysis of volatile organic compounds detected by ion mobility spectrometry (IMS) may enable a quick and sensitive point-of-care testing alternative. In this proof-of-concept study, we investigated whether gas analysis by IMS can discriminate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from other respiratory viruses in an experimental set-up. Repeated gas analyses of air samples collected from the headspace of virus-infected in vitro cultures were performed for 5 days. A three-step decision tree using the intensities of four spectrometry peaks correlating to unidentified volatile organic compounds allowed the correct classification of SARS-CoV-2, human coronavirus-NL63, and influenza A virus H1N1 without misassignment when the calculation was performed with data 3 days post infection. The forward selection assignment model allowed the identification of SARS-CoV-2 with high sensitivity and specificity, with only one of 231 measurements (0.43%) being misclassified. Thus, volatile organic compound analysis by IMS allows highly accurate differentiation of SARS-CoV-2 from other respiratory viruses in an experimental set-up, supporting further research and evaluation in clinical studies.


Subject(s)
Antigens, Viral/isolation & purification , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Point-of-Care Testing , SARS-CoV-2/isolation & purification , Animals , COVID-19/immunology , COVID-19/virology , COVID-19 Serological Testing/instrumentation , Chlorocebus aethiops , Coronavirus NL63, Human/immunology , Coronavirus NL63, Human/isolation & purification , Diagnosis, Differential , High-Throughput Screening Assays/instrumentation , High-Throughput Screening Assays/methods , Humans , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H1N1 Subtype/isolation & purification , Ion Mobility Spectrometry , Proof of Concept Study , SARS-CoV-2/immunology , Vero Cells
15.
Elife ; 102021 10 07.
Article in English | MEDLINE | ID: covidwho-1456505

ABSTRACT

The absence of 'shovel-ready' anti-coronavirus drugs during vaccine development has exceedingly worsened the SARS-CoV-2 pandemic. Furthermore, new vaccine-resistant variants and coronavirus outbreaks may occur in the near future, and we must be ready to face this possibility. However, efficient antiviral drugs are still lacking to this day, due to our poor understanding of the mode of incorporation and mechanism of action of nucleotides analogs that target the coronavirus polymerase to impair its essential activity. Here, we characterize the impact of remdesivir (RDV, the only FDA-approved anti-coronavirus drug) and other nucleotide analogs (NAs) on RNA synthesis by the coronavirus polymerase using a high-throughput, single-molecule, magnetic-tweezers platform. We reveal that the location of the modification in the ribose or in the base dictates the catalytic pathway(s) used for its incorporation. We show that RDV incorporation does not terminate viral RNA synthesis, but leads the polymerase into backtrack as far as 30 nt, which may appear as termination in traditional ensemble assays. SARS-CoV-2 is able to evade the endogenously synthesized product of the viperin antiviral protein, ddhCTP, though the polymerase incorporates this NA well. This experimental paradigm is essential to the discovery and development of therapeutics targeting viral polymerases.


To multiply and spread from cell to cell, the virus responsible for COVID-19 (also known as SARS-CoV-2) must first replicate its genetic information. This process involves a 'polymerase' protein complex making a faithful copy by assembling a precise sequence of building blocks, or nucleotides. The only drug approved against SARS-CoV-2 by the US Food and Drug Administration (FDA), remdesivir, consists of a nucleotide analog, a molecule whose structure is similar to the actual building blocks needed for replication. If the polymerase recognizes and integrates these analogs into the growing genetic sequence, the replication mechanism is disrupted, and the virus cannot multiply. Most approaches to study this process seem to indicate that remdesivir works by stopping the polymerase and terminating replication altogether. Yet, exactly how remdesivir and other analogs impair the synthesis of new copies of the virus remains uncertain. To explore this question, Seifert, Bera et al. employed an approach called magnetic tweezers which uses a magnetic field to manipulate micro-particles with great precision. Unlike other methods, this technique allows analogs to be integrated under conditions similar to those found in cells, and to be examined at the level of a single molecule. The results show that contrary to previous assumptions, remdesivir does not terminate replication; instead, it causes the polymerase to pause and backtrack (which may appear as termination in other techniques). The same approach was then applied to other nucleotide analogs, some of which were also found to target the SARS-CoV-2 polymerase. However, these analogs are incorporated differently to remdesivir and with less efficiency. They also obstruct the polymerase in distinct ways. Taken together, the results by Seifert, Bera et al. suggest that magnetic tweezers can be a powerful approach to reveal how analogs interfere with replication. This information could be used to improve currently available analogs as well as develop new antiviral drugs that are more effective against SARS-CoV-2. This knowledge will be key at a time when treatments against COVID-19 are still lacking, and may be needed to protect against new variants and future outbreaks.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus RNA-Dependent RNA Polymerase/antagonists & inhibitors , Nucleotides/pharmacology , SARS-CoV-2/drug effects , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Alanine/analogs & derivatives , Alanine/pharmacology , Cell Line , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Enzyme Inhibitors/pharmacology , High-Throughput Screening Assays/methods , Humans , Models, Theoretical , Nucleotides/metabolism , RNA, Viral , SARS-CoV-2/enzymology , Stochastic Processes , Virus Replication/drug effects
16.
Microbiol Spectr ; 9(2): e0050621, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1455679

ABSTRACT

Emerging SARS-CoV-2 (SC-2) variants with increased infectivity and vaccine resistance are of major concern. Rapid identification of such variants is important for the public health decision making and to provide valuable data for epidemiological and policy decision making. We developed a multiplex reverse transcriptase quantitative PCR (RT-qPCR) assay that can specifically identify and differentiate between the emerging B.1.1.7 and B.1.351 SC-2 variants. In a single assay, we combined four reactions-one that detects SC-2 RNA independently of the strain, one that detects the D3L mutation, which is specific to variant B.1.1.7, one that detects the 242 to 244 deletion, which is specific to variant B.1.351, and the fourth reaction, which identifies the human RNAseP gene, serving as an endogenous control for RNA extraction integrity. We show that the strain-specific reactions target mutations that are strongly associated with the target variants and not with other major known variants. The assay's specificity was tested against a panel of respiratory pathogens (n = 16), showing high specificity toward SC-2 RNA. The assay's sensitivity was assessed using both in vitro transcribed RNA and clinical samples and was determined to be between 20 and 40 viral RNA copies per reaction. The assay performance was corroborated with Sanger and whole-genome sequencing, showing complete agreement with the sequencing results. The new assay is currently implemented in the routine diagnostic work at the Central Virology Laboratory, and may be used in other laboratories to facilitate the diagnosis of these major worldwide-circulating SC-2 variants. IMPORTANCE This study describes the design and utilization of a multiplex reverse transcriptase quantitative PCR (RT-qPCR) to identify SARS-COV-2 (SC2) RNA in general and, specifically, to detect whether it is of lineage B.1.1.7 or B.1.351. Implementation of this method in diagnostic and research laboratories worldwide may help the efforts to contain the COVID-19 pandemic. The method can be easily scaled up and be used in high-throughput laboratories, as well as small ones. In addition to immediate help in diagnostic efforts, this method may also help in epidemiological studies focused on the spread of emerging SC-2 lineages.


Subject(s)
COVID-19/diagnosis , High-Throughput Nucleotide Sequencing/methods , High-Throughput Screening Assays/methods , SARS-CoV-2/classification , SARS-CoV-2/genetics , COVID-19/epidemiology , COVID-19/virology , Genome, Viral/genetics , Humans , Israel/epidemiology , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Whole Genome Sequencing
17.
Cell Rep ; 37(1): 109784, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1442299

ABSTRACT

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineages that are more transmissible and resistant to currently approved antibody therapies poses a considerable challenge to the clinical treatment of coronavirus disease (COVID-19). Therefore, the need for ongoing discovery efforts to identify broadly reactive monoclonal antibodies to SARS-CoV-2 is of utmost importance. Here, we report a panel of SARS-CoV-2 antibodies isolated using the linking B cell receptor to antigen specificity through sequencing (LIBRA-seq) technology from an individual who recovered from COVID-19. Of these antibodies, 54042-4 shows potent neutralization against authentic SARS-CoV-2 viruses, including variants of concern (VOCs). A cryoelectron microscopy (cryo-EM) structure of 54042-4 in complex with the SARS-CoV-2 spike reveals an epitope composed of residues that are highly conserved in currently circulating SARS-CoV-2 lineages. Further, 54042-4 possesses uncommon genetic and structural characteristics that distinguish it from other potently neutralizing SARS-CoV-2 antibodies. Together, these findings provide motivation for the development of 54042-4 as a lead candidate to counteract current and future SARS-CoV-2 VOCs.


Subject(s)
Angiotensin-Converting Enzyme 2/immunology , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , COVID-19/immunology , SARS-CoV-2/chemistry , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/chemistry , Animals , Antibodies, Viral/immunology , Antibody Formation , COVID-19/genetics , COVID-19/virology , Cell Line , Chlorocebus aethiops , Cryoelectron Microscopy , Epitope Mapping/methods , Epitopes/chemistry , Epitopes/immunology , High-Throughput Screening Assays/methods , Humans , Male , Middle Aged , Protein Binding , Protein Interaction Domains and Motifs , Receptors, Antigen, B-Cell/chemistry , Receptors, Antigen, B-Cell/immunology , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Vero Cells
18.
Molecules ; 26(18)2021 Sep 18.
Article in English | MEDLINE | ID: covidwho-1430926

ABSTRACT

Sample preparation is an essential step for nearly every type of biochemical analysis in use today. Among the most important of these analyses is the diagnosis of diseases, since their treatment may rely greatly on time and, in the case of infectious diseases, containing their spread within a population to prevent outbreaks. To address this, many different methods have been developed for use in the wide variety of settings for which they are needed. In this work, we have reviewed the literature and report on a broad range of methods that have been developed in recent years and their applications to point-of-care (POC), high-throughput screening, and low-resource and traditional clinical settings for diagnosis, including some of those that were developed in response to the coronavirus disease 2019 (COVID-19) pandemic. In addition to covering alternative approaches and improvements to traditional sample preparation techniques such as extractions and separations, techniques that have been developed with focuses on integration with smart devices, laboratory automation, and biosensors are also discussed.


Subject(s)
High-Throughput Screening Assays/methods , Specimen Handling/methods , Biosensing Techniques/methods , COVID-19 , Communicable Diseases/diagnosis , High-Throughput Screening Assays/trends , Humans , Pandemics/prevention & control , Point-of-Care Systems/trends , Point-of-Care Testing/trends , SARS-CoV-2
19.
Sci Rep ; 11(1): 17793, 2021 09 07.
Article in English | MEDLINE | ID: covidwho-1397895

ABSTRACT

The rapid identification and isolation of infected individuals remains a key strategy for controlling the spread of SARS-CoV-2. Frequent testing of populations to detect infection early in asymptomatic or presymptomatic individuals can be a powerful tool for intercepting transmission, especially when the viral prevalence is low. However, RT-PCR testing-the gold standard of SARS-CoV-2 diagnosis-is expensive, making regular testing of every individual unfeasible. Sample pooling is one approach to lowering costs. By combining samples and testing them in groups the number of tests required is reduced, substantially lowering costs. Here we report on the implementation of pooling strategies using 3-d and 4-d hypercubes to test a professional sports team in South Africa. We have shown that infected samples can be reliably detected in groups of 27 and 81, with minimal loss of assay sensitivity for samples with individual Ct values of up to 32. We report on the automation of sample pooling, using a liquid-handling robot and an automated web interface to identify positive samples. We conclude that hypercube pooling allows for the reliable RT-PCR detection of SARS-CoV-2 infection, at significantly lower costs than lateral flow antigen (LFA) tests.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , High-Throughput Screening Assays/methods , SARS-CoV-2/isolation & purification , Specimen Handling/methods , Antigens, Viral/isolation & purification , Athletes , COVID-19/blood , COVID-19/virology , COVID-19 Nucleic Acid Testing/economics , COVID-19 Serological Testing/economics , COVID-19 Serological Testing/methods , Cost Savings , High-Throughput Screening Assays/economics , Humans , RNA, Viral/isolation & purification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Sensitivity and Specificity , South Africa , Specimen Handling/economics , Sports Medicine/economics , Sports Medicine/methods
20.
PLoS One ; 16(9): e0248444, 2021.
Article in English | MEDLINE | ID: covidwho-1394535

ABSTRACT

The pandemic of novel coronavirus disease COVID-19 is rapidly expanding across the world. A positive result of antibody tests suggests that the individual has potentially been exposed to SARS-CoV-2, thus allowing to identify asymptomatic infections and determine the seroprevalence in a given population. The aim of this study was to evaluate the performances of a newly developed high throughput immunoassay for anti-SARS-CoV-2 IgM antibody detection on the Luminex MAGPIX platform. Clinical agreement studies were performed in 42 COVID-19 patient serum samples and 162 negative donor serum/plasma samples. Positive percent agreement (PPA) was 42.86% (95% CI: 9.90% to 81.59%), 71.43% (95% CI: 29.04% to 96.33%), and 28.57% (95% CI: 13.22% to 48.67%) for samples collected on 0-7 days, 8-14 days, and 2-8 weeks from symptom onset, respectively. Negative Percent Agreement (NPA) was 97.53% (95% CI: 93.80% to 99.32%). There was no cross-reactivity with the SARS-CoV-2 IgG antibody. Hemoglobin (200 mg/dL), bilirubin (2 mg/dL), triglyceride (250 mg/dL) and EDTA (10 mM) showed no significant interfering effect on this assay. In conclusion, an anti-SARS-CoV-2 IgM antibody assay with high sensitivity and specificity has been developed. With the high throughput, this assay will speed up the anti-SARS-CoV-2 IgM testing.


Subject(s)
Antibodies, Viral/immunology , COVID-19 Serological Testing/methods , Immunoassay/methods , Immunoglobulin M/immunology , Microspheres , SARS-CoV-2/immunology , Antibodies, Viral/blood , High-Throughput Screening Assays/methods , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin M/blood , ROC Curve , SARS-CoV-2/physiology
SELECTION OF CITATIONS
SEARCH DETAIL