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1.
ACS measurement science Au ; 2022.
Article in English | EuropePMC | ID: covidwho-1688311

ABSTRACT

Samples of nasopharyngeal swabs (NPS) are commonly used for the detection of SARS-CoV-2 and diagnosis of COVID-19. As an alternative, self-collection of saliva and gargle samples minimizes transmission to healthcare workers and relieves the pressure of resources and healthcare personnel during the pandemic. This study aimed to develop an enhanced method enabling simultaneous viral inactivation and RNA preservation during on-site self-collection of saliva and gargle samples. Our method involves the addition of saliva or gargle samples to a newly formulated viral inactivation and RNA preservation (VIP) buffer, concentration of the viral RNA on magnetic beads, and detection of SARS-CoV-2 using reverse transcription quantitative polymerase chain reaction directly from the magnetic beads. This method has a limit of detection of 25 RNA copies per 200 μL of gargle or saliva sample and 9–111 times higher sensitivity than the viral RNA preparation kit recommended by the United States Centers for Disease Control and Prevention. The integrated method was successfully used to analyze more than 200 gargle and saliva samples, including the detection of SARS-CoV-2 in 123 gargle and saliva samples collected daily from two NPS-confirmed positive SARS-CoV-2 patients throughout the course of their infection and recovery. The VIP buffer is stable at room temperature for at least 6 months. SARS-CoV-2 RNA (65 copies/200 μL sample) is stable in the VIP buffer at room temperature for at least 3 weeks. The on-site inactivation of SARS-CoV-2 and preservation of the viral RNA enables self-collection of samples, reduces risks associated with SARS-CoV-2 transmission, and maintains the stability of the target analyte.

2.
BMC Pharmacol Toxicol ; 22(1): 61, 2021 10 21.
Article in English | MEDLINE | ID: covidwho-1477468

ABSTRACT

BACKGROUND: The emergence and rapid spread of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) in thelate 2019 has caused a devastating global pandemic of the severe pneumonia-like disease coronavirus disease 2019 (COVID-19). Although vaccines have been and are being developed, they are not accessible to everyone and not everyone can receive these vaccines. Also, it typically takes more than 10 years until a new therapeutic agent is approved for usage. Therefore, repurposing of known drugs can lend itself well as a key approach for significantly expediting the development of new therapies for COVID-19. METHODS: We have incorporated machine learning-based computational tools and in silico models into the drug discovery process to predict Adsorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) profiles of 90 potential drugs for COVID-19 treatment identified from two independent studies mainly with the purpose of mitigating late-phase failures because of inferior pharmacokinetics and toxicity. RESULTS: Here, we summarize the cardiotoxicity and general toxicity profiles of 90 potential drugs for COVID-19 treatment and outline the risks of repurposing and propose a stratification of patients accordingly. We shortlist a total of five compounds based on their non-toxic properties. CONCLUSION: In summary, this manuscript aims to provide a potentially useful source of essential knowledge on toxicity assessment of 90 compounds for healthcare practitioners and researchers to find off-label alternatives for the treatment for COVID-19. The majority of the molecules discussed in this manuscript have already moved into clinical trials and thus their known pharmacological and human safety profiles are expected to facilitate a fast track preclinical and clinical assessment for treating COVID-19.


Subject(s)
Antiviral Agents/toxicity , COVID-19/drug therapy , Drug Discovery , Drug Repositioning , Animals , Antiviral Agents/adverse effects , Captopril/therapeutic use , Cardiotoxins/toxicity , Catechols/therapeutic use , Computational Biology , Cytochrome P-450 Enzyme System/metabolism , Drug Discovery/methods , Humans , Indomethacin/therapeutic use , Linezolid/therapeutic use , Liver/drug effects , Mice , Models, Biological , Nitriles/therapeutic use , Rats , Reproduction/drug effects , Software , Valproic Acid/therapeutic use
3.
Anal Chem ; 93(37): 12808-12816, 2021 09 21.
Article in English | MEDLINE | ID: covidwho-1402013

ABSTRACT

CRISPR-Cas systems integrated with nucleic acid amplification techniques improve both analytical specificity and sensitivity. We describe here issues and solutions for the successful integration of reverse transcription (RT), recombinase polymerase amplification (RPA), and CRISPR-Cas12a nuclease reactions into a single tube under an isothermal condition (40 °C). Specific detection of a few copies of a viral DNA sequence was achieved in less than 20 min. However, the sensitivity was orders of magnitude lower for the detection of viral RNA due to the slow initiation of RPA when the complementary DNA (cDNA) template remained hybridized to RNA. During the delay of RPA, the crRNA-Cas12a ribonucleoprotein (RNP) gradually lost its activity in the RPA solution, and nonspecific amplification reactions consumed the RPA reagents. We overcame these problems by taking advantage of the endoribonuclease function of RNase H to remove RNA from the RNA-cDNA hybrids and free the cDNA as template for the RPA reaction. As a consequence, we significantly enhanced the overall reaction rate of an integrated assay using RT-RPA and CRISPR-Cas12a for the detection of RNA. We showed successful detection of 200 or more copies of the S gene sequence of SARS-CoV-2 RNA within 5-30 min. We applied our one-tube assay to 46 upper respiratory swab samples for COVID-19 diagnosis, and the results from both fluorescence intensity measurements and end-point visualization were consistent with those of RT-qPCR analysis. The strategy and technique improve the sensitivity and speed of RT-RPA and CRISPR-Cas12a assays, potentially useful for both semi-quantitative and point-of-care analyses of RNA molecules.


Subject(s)
COVID-19 , Reverse Transcription , COVID-19 Testing , Humans , Nucleic Acid Amplification Techniques , RNA, Viral/genetics , Recombinases/genetics , SARS-CoV-2 , Sensitivity and Specificity , Technology
4.
RSC Med Chem ; 12(10): 1722-1730, 2021 Oct 20.
Article in English | MEDLINE | ID: covidwho-1392908

ABSTRACT

Tragically, the death toll from the COVID-19 pandemic continues to rise, and with variants being observed around the globe new therapeutics, particularly direct-acting antivirals that are easily administered, are desperately needed. Studies targeting the SARS-CoV-2 3CL protease, which is critical for viral replication, with different peptidomimetics and warheads is an active area of research for development of potential drugs. To date, however, only a few publications have evaluated the nitrile warhead as a viral 3CL protease inhibitor, with only modest activity reported. This article describes our investigation of P3 4-methoxyindole peptidomimetic analogs with select P1 and P2 groups with a nitrile warhead that are potent inhibitors of SARS-CoV-2 3CL protease and demonstrate in vitro SARS-CoV-2 antiviral activity. A selectivity for SARS-CoV-2 3CL protease over human cathepsins B, S and L was also observed with the nitrile warhead, which was superior to that with the aldehyde warhead. A co-crystal structure with SARS-CoV-2 3CL protease and a reversibility study indicate that a reversible, thioimidate adduct is formed when the catalytic sulfur forms a covalent bond with the carbon of the nitrile. This effort also identified efflux as a property limiting antiviral activity of these compounds, and together with the positive attributes described these results provide insight for further drug development of novel nitrile peptidomimetics targeting SARS-CoV-2 3CL protease.

5.
Vaccine ; 39(40): 5769-5779, 2021 09 24.
Article in English | MEDLINE | ID: covidwho-1392616

ABSTRACT

SARS-CoV-2 is the etiological agent of COVID19. There are currently several licensed vaccines approved for human use and most of them target the spike protein in the virion envelope to induce protective immunity. Recently, variants that spread more quickly have emerged. There is evidence that some of these variants are less sensitive to neutralization in vitro, but it is not clear whether they can evade vaccine induced protection. In this study, we tested SARS-CoV-2 spike RBD as a vaccine antigen and explored the effect of formulation with Alum/MPLA or AddaS03 adjuvants. Our results show that RBD induces high titers of neutralizing antibodies and activates strong cellular immune responses. There is also significant cross-neutralization of variants B.1.1.7 and B.1.351 and to a lesser extent, SARS-CoV-1. These results indicate that recombinant RBD can be a viable candidate as a stand-alone vaccine or as a booster shot to diversify our strategy for COVID19 protection.


Subject(s)
Antibodies, Neutralizing , COVID-19 , Antibodies, Viral , Humans , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics
6.
J Med Chem ; 65(4): 2905-2925, 2022 02 24.
Article in English | MEDLINE | ID: covidwho-1303733

ABSTRACT

Recurring coronavirus outbreaks, such as the current COVID-19 pandemic, establish a necessity to develop direct-acting antivirals that can be readily administered and are active against a broad spectrum of coronaviruses. Described in this Article are novel α-acyloxymethylketone warhead peptidomimetic compounds with a six-membered lactam glutamine mimic in P1. Compounds with potent SARS-CoV-2 3CL protease and in vitro viral replication inhibition were identified with low cytotoxicity and good plasma and glutathione stability. Compounds 15e, 15h, and 15l displayed selectivity for SARS-CoV-2 3CL protease over CatB and CatS and superior in vitro SARS-CoV-2 antiviral replication inhibition compared with the reported peptidomimetic inhibitors with other warheads. The cocrystallization of 15l with SARS-CoV-2 3CL protease confirmed the formation of a covalent adduct. α-Acyloxymethylketone compounds also exhibited antiviral activity against an alphacoronavirus and non-SARS betacoronavirus strains with similar potency and a better selectivity index than remdesivir. These findings demonstrate the potential of the substituted heteroaromatic and aliphatic α-acyloxymethylketone warheads as coronavirus inhibitors, and the described results provide a basis for further optimization.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Cysteine Proteinase Inhibitors/pharmacology , Peptidomimetics/pharmacology , SARS-CoV-2/drug effects , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , COVID-19/drug therapy , COVID-19/metabolism , Coronavirus 3C Proteases/metabolism , Cysteine Proteinase Inhibitors/chemical synthesis , Cysteine Proteinase Inhibitors/chemistry , Glutamine/chemistry , Glutamine/pharmacology , Humans , Ketones/chemistry , Ketones/pharmacology , Microbial Sensitivity Tests , Molecular Structure , Peptidomimetics/chemistry , SARS-CoV-2/enzymology , Virus Replication/drug effects
7.
J Mol Biol ; 433(13): 167003, 2021 06 25.
Article in English | MEDLINE | ID: covidwho-1272546

ABSTRACT

The main protease (Mpro, also known as 3CL protease) of SARS-CoV-2 is a high priority drug target in the development of antivirals to combat COVID-19 infections. A feline coronavirus antiviral drug, GC376, has been shown to be effective in inhibiting the SARS-CoV-2 main protease and live virus growth. As this drug moves into clinical trials, further characterization of GC376 with the main protease of coronaviruses is required to gain insight into the drug's properties, such as reversibility and broad specificity. Reversibility is an important factor for therapeutic proteolytic inhibitors to prevent toxicity due to off-target effects. Here we demonstrate that GC376 has nanomolar Ki values with the Mpro from both SARS-CoV-2 and SARS-CoV strains. Restoring enzymatic activity after inhibition by GC376 demonstrates reversible binding with both proteases. In addition, the stability and thermodynamic parameters of both proteases were studied to shed light on physical chemical properties of these viral enzymes, revealing higher stability for SARS-CoV-2 Mpro. The comparison of a new X-ray crystal structure of Mpro from SARS-CoV complexed with GC376 reveals similar molecular mechanism of inhibition compared to SARS-CoV-2 Mpro, and gives insight into the broad specificity properties of this drug. In both structures, we observe domain swapping of the N-termini in the dimer of the Mpro, which facilitates coordination of the drug's P1 position. These results validate that GC376 is a drug with an off-rate suitable for clinical trials.


Subject(s)
Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Pyrrolidines/chemistry , Pyrrolidines/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19/drug therapy , Cats , Coronavirus 3C Proteases/metabolism , Molecular Docking Simulation , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , SARS-CoV-2/enzymology , Sulfonic Acids , Thermodynamics , Viral Nonstructural Proteins/chemistry
8.
Eur J Med Chem ; 222: 113584, 2021 Oct 15.
Article in English | MEDLINE | ID: covidwho-1252810

ABSTRACT

Replication of SARS-CoV-2, the coronavirus causing COVID-19, requires a main protease (Mpro) to cleave viral proteins. Consequently, Mpro is a target for antiviral agents. We and others previously demonstrated that GC376, a bisulfite prodrug with efficacy as an anti-coronaviral agent in animals, is an effective inhibitor of Mpro in SARS-CoV-2. Here, we report structure-activity studies of improved GC376 derivatives with nanomolar affinities and therapeutic indices >200. Crystallographic structures of inhibitor-Mpro complexes reveal that an alternative binding pocket in Mpro, S4, accommodates the P3 position. Alternative binding is induced by polar P3 groups or a nearby methyl. NMR and solubility studies with GC376 show that it exists as a mixture of stereoisomers and forms colloids in aqueous media at higher concentrations, a property not previously reported. Replacement of its Na+ counter ion with choline greatly increases solubility. The physical, biochemical, crystallographic, and cellular data reveal new avenues for Mpro inhibitor design.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Cysteine Proteinase Inhibitors/pharmacology , Pyrrolidines/pharmacology , SARS-CoV-2/drug effects , Sulfonic Acids/pharmacology , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/metabolism , Binding Sites , Chlorocebus aethiops , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/metabolism , Crystallography, X-Ray , Cysteine Proteinase Inhibitors/chemical synthesis , Cysteine Proteinase Inhibitors/metabolism , Humans , Micelles , Microbial Sensitivity Tests , Molecular Structure , Protein Binding , Pyrrolidines/chemical synthesis , Pyrrolidines/metabolism , SARS-CoV-2/enzymology , Solubility , Structure-Activity Relationship , Sulfonic Acids/chemical synthesis , Sulfonic Acids/metabolism , Vero Cells
9.
Stem Cell Reports ; 16(5): 1165-1181, 2021 05 11.
Article in English | MEDLINE | ID: covidwho-1225410

ABSTRACT

SARS-CoV-2 infection is associated with lower blood oxygen levels, even in patients without hypoxia requiring hospitalization. This discordance illustrates the need for a more unifying explanation as to whether SARS-CoV-2 directly or indirectly affects erythropoiesis. Here, we show significantly enriched CD71+ erythroid precursors/progenitors in the blood circulation of COVID-19 patients. We found that these cells have distinctive immunosuppressive properties. In agreement, we observed a strong negative correlation between the frequency of these cells with T and B cell proportions in COVID-19 patients. The expansion of these CD71+ erythroid precursors/progenitors was negatively correlated with the hemoglobin levels. A subpopulation of abundant erythroid cells, CD45+ CD71+ cells, co-express ACE2, TMPRSS2, CD147, and CD26, and these can be infected with SARS-CoV-2. In turn, pre-treatment of erythroid cells with dexamethasone significantly diminished ACE2/TMPRSS2 expression and subsequently reduced their infectivity with SARS-CoV-2. This provides a novel insight into the impact of SARS-CoV-2 on erythropoiesis and hypoxia seen in COVID-19 patients.


Subject(s)
Adaptive Immunity/immunology , COVID-19/pathology , Erythroid Precursor Cells/virology , Erythropoiesis/physiology , Hemoglobins/analysis , Oxygen/blood , Adolescent , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/metabolism , Animals , B-Lymphocytes/cytology , B-Lymphocytes/immunology , COVID-19/immunology , Dexamethasone/pharmacology , Erythroid Precursor Cells/immunology , Female , Humans , Lymphocyte Count , Male , Mice , Mice, Inbred BALB C , Middle Aged , SARS-CoV-2/immunology , Serine Endopeptidases/metabolism , T-Lymphocytes/cytology , T-Lymphocytes/immunology , Young Adult
10.
Chem Sci ; 12(13): 4683-4698, 2021 Mar 02.
Article in English | MEDLINE | ID: covidwho-1189294

ABSTRACT

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) protein systems have transformed the field of genome editing and transcriptional modulation. Progress in CRISPR-Cas technology has also advanced molecular detection of diverse targets, ranging from nucleic acids to proteins. Incorporating CRISPR-Cas systems with various nucleic acid amplification strategies enables the generation of amplified detection signals, enrichment of low-abundance molecular targets, improvements in analytical specificity and sensitivity, and development of point-of-care (POC) diagnostic techniques. These systems take advantage of various Cas proteins for their particular features, including RNA-guided endonuclease activity, sequence-specific recognition, multiple turnover trans-cleavage activity of Cas12 and Cas13, and unwinding and nicking ability of Cas9. Integrating a CRISPR-Cas system after nucleic acid amplification improves detection specificity due to RNA-guided recognition of specific sequences of amplicons. Incorporating CRISPR-Cas before nucleic acid amplification enables enrichment of rare and low-abundance nucleic acid targets and depletion of unwanted abundant nucleic acids. Unwinding of dsDNA to ssDNA using CRISPR-Cas9 at a moderate temperature facilitates techniques for achieving isothermal exponential amplification of nucleic acids. A combination of CRISPR-Cas systems with functional nucleic acids (FNAs) and molecular translators enables the detection of non-nucleic acid targets, such as proteins, metal ions, and small molecules. Successful integrations of CRISPR technology with nucleic acid amplification techniques result in highly sensitive and rapid detection of SARS-CoV-2, the virus that causes the COVID-19 pandemic.

11.
Clin Transl Immunology ; 10(3): e1260, 2021.
Article in English | MEDLINE | ID: covidwho-1120050

ABSTRACT

OBJECTIVES: A major COVID-19 vaccine strategy is to induce antibodies that prevent interaction between the Spike protein's receptor-binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2). These vaccines will also induce T-cell responses. However, concerns were raised that aberrant vaccine-induced immune responses may exacerbate disease. We aimed to identify minimal epitopes on the RBD that would induce antibody responses that block the interaction of the RBD and ACE2 as a strategy leading to an effective vaccine with reduced risk of inducing immunopathology. METHODS: We procured a series of overlapping 20-amino acid peptides spanning the RBD and asked which were recognised by plasma from COVID-19 convalescent patients. Identified epitopes were conjugated to diphtheria-toxoid and used to vaccinate mice. Immune sera were tested for binding to the RBD and for their ability to block the interaction of the RBD and ACE2. RESULTS: Seven putative vaccine epitopes were identified. Memory B-cells (MBCs) specific for one of the epitopes were identified in the blood of convalescent patients. When used to vaccinate mice, six induced antibodies that bound recRBD and three induced antibodies that could partially block the interaction of the RBD and ACE2. However, when the sera were combined in pairs, we observed significantly enhanced inhibition of binding of RBD to ACE2. Two of the peptides were located in the main regions of the RBD known to contact ACE2. Of significant importance to vaccine development, two of the peptides were in regions that are invariant in the UK and South African strains. CONCLUSION: COVID-19 convalescent patients have SARS-CoV-2-specific antibodies and MBCs, the specificities of which can be defined with short peptides. Epitope-specific antibodies synergistically block RBD-ACE2 interaction.

12.
Anal Chem ; 92(24): 16204-16212, 2020 12 15.
Article in English | MEDLINE | ID: covidwho-947511

ABSTRACT

We have developed a single-tube assay for SARS-CoV-2 in patient samples. This assay combined advantages of reverse transcription (RT) loop-mediated isothermal amplification (LAMP) with clustered regularly interspaced short palindromic repeats (CRISPRs) and the CRISPR-associated (Cas) enzyme Cas12a. Our assay is able to detect SARS-CoV-2 in a single tube within 40 min, requiring only a single temperature control (62 °C). The RT-LAMP reagents were added to the sample vial, while CRISPR Cas12a reagents were deposited onto the lid of the vial. After a half-hour RT-LAMP amplification, the tube was inverted and flicked to mix the detection reagents with the amplicon. The sequence-specific recognition of the amplicon by the CRISPR guide RNA and Cas12a enzyme improved specificity. Visible green fluorescence generated by the CRISPR Cas12a system was recorded using a smartphone camera. Analysis of 100 human respiratory swab samples for the N and/or E gene of SARS-CoV-2 produced 100% clinical specificity and no false positive. Analysis of 50 samples that were detected positive using reverse transcription quantitative polymerase chain reaction (RT-qPCR) resulted in an overall clinical sensitivity of 94%. Importantly, this included 20 samples that required 30-39 threshold cycles of RT-qPCR to achieve a positive detection. Integration of the exponential amplification ability of RT-LAMP and the sequence-specific processing by the CRISPR-Cas system into a molecular assay resulted in improvements in both analytical sensitivity and specificity. The single-tube assay is beneficial for future point-of-care applications.


Subject(s)
CRISPR-Cas Systems/genetics , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , Nucleic Acid Amplification Techniques , SARS-CoV-2/genetics , Humans , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction
13.
Nat Commun ; 11(1): 5409, 2020 Oct 20.
Article in English | MEDLINE | ID: covidwho-882896

ABSTRACT

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

14.
Nat Genet ; 52(12): 1283-1293, 2020 12.
Article in English | MEDLINE | ID: covidwho-880695

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, utilizes angiotensin-converting enzyme 2 (ACE2) for entry into target cells. ACE2 has been proposed as an interferon-stimulated gene (ISG). Thus, interferon-induced variability in ACE2 expression levels could be important for susceptibility to COVID-19 or its outcomes. Here, we report the discovery of a novel, transcriptionally independent truncated isoform of ACE2, which we designate as deltaACE2 (dACE2). We demonstrate that dACE2, but not ACE2, is an ISG. In The Cancer Genome Atlas, the expression of dACE2 was enriched in squamous tumors of the respiratory, gastrointestinal and urogenital tracts. In vitro, dACE2, which lacks 356 amino-terminal amino acids, was non-functional in binding the SARS-CoV-2 spike protein and as a carboxypeptidase. Our results suggest that the ISG-type induction of dACE2 in IFN-high conditions created by treatments, an inflammatory tumor microenvironment or viral co-infections is unlikely to increase the cellular entry of SARS-CoV-2 and promote infection.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Interferons/metabolism , RNA Viruses/physiology , Receptors, Coronavirus/metabolism , SARS-CoV-2/metabolism , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Carcinoma, Squamous Cell/enzymology , Carcinoma, Squamous Cell/genetics , Cell Line , Enzyme Induction , Gene Expression Profiling , Gene Expression Regulation, Enzymologic , Humans , Isoenzymes/chemistry , Isoenzymes/genetics , Isoenzymes/metabolism , Receptors, Coronavirus/genetics , Respiratory Mucosa/metabolism , Respiratory Mucosa/virology , Spike Glycoprotein, Coronavirus/metabolism
15.
Nat Commun ; 11(1): 4282, 2020 08 27.
Article in English | MEDLINE | ID: covidwho-733525

ABSTRACT

The main protease, Mpro (or 3CLpro) in SARS-CoV-2 is a viable drug target because of its essential role in the cleavage of the virus polypeptide. Feline infectious peritonitis, a fatal coronavirus infection in cats, was successfully treated previously with a prodrug GC376, a dipeptide-based protease inhibitor. Here, we show the prodrug and its parent GC373, are effective inhibitors of the Mpro from both SARS-CoV and SARS-CoV-2 with IC50 values in the nanomolar range. Crystal structures of SARS-CoV-2 Mpro with these inhibitors have a covalent modification of the nucleophilic Cys145. NMR analysis reveals that inhibition proceeds via reversible formation of a hemithioacetal. GC373 and GC376 are potent inhibitors of SARS-CoV-2 replication in cell culture. They are strong drug candidates for the treatment of human coronavirus infections because they have already been successful in animals. The work here lays the framework for their use in human trials for the treatment of COVID-19.


Subject(s)
Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus, Feline/drug effects , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , A549 Cells , Animals , Antiviral Agents/chemistry , Betacoronavirus/enzymology , Binding Sites , Chlorocebus aethiops , Coronavirus 3C Proteases , Coronavirus, Feline/enzymology , Crystallography, X-Ray , Cysteine Endopeptidases/chemistry , Cytopathogenic Effect, Viral/drug effects , Drug Repositioning , Humans , Inhibitory Concentration 50 , Molecular Structure , Prodrugs , Protease Inhibitors/chemistry , Pyrrolidines/chemistry , Pyrrolidines/pharmacology , SARS Virus/drug effects , SARS Virus/enzymology , SARS-CoV-2 , Sulfonic Acids , Vero Cells , Viral Nonstructural Proteins/chemistry , Virus Replication/drug effects
16.
Anal Chem ; 92(15): 10196-10209, 2020 08 04.
Article in English | MEDLINE | ID: covidwho-612210

ABSTRACT

Molecular diagnosis of COVID-19 primarily relies on the detection of RNA of the SARS-CoV-2 virus, the causative infectious agent of the pandemic. Reverse transcription polymerase chain reaction (RT-PCR) enables sensitive detection of specific sequences of genes that encode the RNA dependent RNA polymerase (RdRP), nucleocapsid (N), envelope (E), and spike (S) proteins of the virus. Although RT-PCR tests have been widely used and many alternative assays have been developed, the current testing capacity and availability cannot meet the unprecedented global demands for rapid, reliable, and widely accessible molecular diagnosis. Challenges remain throughout the entire analytical process, from the collection and treatment of specimens to the amplification and detection of viral RNA and the validation of clinical sensitivity and specificity. We highlight the main issues surrounding molecular diagnosis of COVID-19, including false negatives from the detection of viral RNA, temporal variations of viral loads, selection and treatment of specimens, and limiting factors in detecting viral proteins. We discuss critical research needs, such as improvements in RT-PCR, development of alternative nucleic acid amplification techniques, incorporating CRISPR technology for point-of-care (POC) applications, validation of POC tests, and sequencing of viral RNA and its mutations. Improved assays are also needed for environmental surveillance or wastewater-based epidemiology, which gauges infection on the community level through analyses of viral components in the community's wastewater. Public health surveillance benefits from large-scale analyses of antibodies in serum, although the current serological tests do not quantify neutralizing antibodies. Further advances in analytical technology and research through multidisciplinary collaboration will contribute to the development of mitigation strategies, therapeutics, and vaccines. Lessons learned from molecular diagnosis of COVID-19 are valuable for better preparedness in response to other infectious diseases.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , RNA, Viral/analysis , Betacoronavirus/chemistry , COVID-19 , COVID-19 Testing , CRISPR-Cas Systems , Clinical Laboratory Techniques , False Negative Reactions , High-Throughput Nucleotide Sequencing , Humans , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , Pandemics , Point-of-Care Testing , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Specimen Handling/methods , Viral Load , Viral Proteins/analysis , Waste Water/analysis
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