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1.
Viruses ; 14(2)2022 02 21.
Article in English | MEDLINE | ID: covidwho-1702211

ABSTRACT

In early 2020, the COVID-19 pandemic sparked a global crisis that continues to pose a serious threat to human health and the economy. Further advancement in research is necessary and requires the availability of quality molecular tools, including monoclonal antibodies. Here, we present the development and characterization of a collection of over 40 new monoclonal antibodies directed against different SARS-CoV-2 proteins. Recombinant SARS-CoV-2 proteins were expressed, purified, and used as immunogens. Upon development of specific hybridomas, the obtained monoclonal antibody (mAb) clones were tested for binding to recombinant proteins and infected cells. We generated mAbs against structural proteins, the Spike and Nucleocapsid protein, several non-structural proteins (nsp1, nsp7, nsp8, nsp9, nsp10, nsp16) and accessory factors (ORF3a, ORF9b) applicable in flow cytometry, immunofluorescence, or Western blot. Our collection of mAbs provides a set of novel, highly specific tools that will allow a comprehensive analysis of the viral proteome, which will allow further understanding of SARS-CoV-2 pathogenesis and the design of therapeutic strategies.


Subject(s)
Antibodies, Monoclonal/pharmacology , Antibodies, Viral/pharmacology , SARS-CoV-2/immunology , Viral Proteins/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/genetics , Antibodies, Monoclonal/classification , Antibodies, Viral/immunology , COVID-19/therapy , COVID-19/virology , HEK293 Cells , Humans , Recombinant Proteins/immunology , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/immunology
2.
Viruses ; 14(2)2022 01 18.
Article in English | MEDLINE | ID: covidwho-1649476

ABSTRACT

Recurrent outbreaks of novel zoonotic coronavirus (CoV) diseases in recent years have highlighted the importance of developing therapeutics with broad-spectrum activity against CoVs. Because all CoVs use -1 programmed ribosomal frameshifting (-1 PRF) to control expression of key viral proteins, the frameshift signal in viral mRNA that stimulates -1 PRF provides a promising potential target for such therapeutics. To test the viability of this strategy, we explored whether small-molecule inhibitors of -1 PRF in SARS-CoV-2 also inhibited -1 PRF in a range of bat CoVs-the most likely source of future zoonoses. Six inhibitors identified in new and previous screens against SARS-CoV-2 were evaluated against the frameshift signals from a panel of representative bat CoVs as well as MERS-CoV. Some drugs had strong activity against subsets of these CoV-derived frameshift signals, while having limited to no effect on -1 PRF caused by frameshift signals from other viruses used as negative controls. Notably, the serine protease inhibitor nafamostat suppressed -1 PRF significantly for multiple CoV-derived frameshift signals. These results suggest it is possible to find small-molecule ligands that inhibit -1 PRF specifically in a broad spectrum of CoVs, establishing frameshift signals as a viable target for developing pan-coronaviral therapeutics.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus/drug effects , Coronavirus/genetics , Frameshift Mutation , Frameshifting, Ribosomal/drug effects , Viral Proteins/antagonists & inhibitors , Animals , Antiviral Agents/therapeutic use , Chiroptera/virology , Coronavirus/classification , Coronavirus Infections/drug therapy , Nucleic Acid Conformation , RNA, Messenger/genetics , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , Viral Proteins/genetics , Virus Replication/drug effects
3.
Nat Commun ; 13(1): 621, 2022 02 02.
Article in English | MEDLINE | ID: covidwho-1671551

ABSTRACT

The guanosine analog AT-527 represents a promising candidate against Severe Acute Respiratory Syndrome coronavirus type 2 (SARS-CoV-2). AT-527 recently entered phase III clinical trials for the treatment of COVID-19. Once in cells, AT-527 is converted into its triphosphate form, AT-9010, that presumably targets the viral RNA-dependent RNA polymerase (RdRp, nsp12), for incorporation into viral RNA. Here we report a 2.98 Å cryo-EM structure of the SARS-CoV-2 nsp12-nsp7-nsp82-RNA complex, showing AT-9010 bound at three sites of nsp12. In the RdRp active-site, one AT-9010 is incorporated at the 3' end of the RNA product strand. Its modified ribose group (2'-fluoro, 2'-methyl) prevents correct alignment of the incoming NTP, in this case a second AT-9010, causing immediate termination of RNA synthesis. The third AT-9010 is bound to the N-terminal domain of nsp12 - known as the NiRAN. In contrast to native NTPs, AT-9010 is in a flipped orientation in the active-site, with its guanine base unexpectedly occupying a previously unnoticed cavity. AT-9010 outcompetes all native nucleotides for NiRAN binding, inhibiting its nucleotidyltransferase activity. The dual mechanism of action of AT-527 at both RdRp and NiRAN active sites represents a promising research avenue against COVID-19.


Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Guanosine Monophosphate/analogs & derivatives , Phosphoramides/chemistry , Phosphoramides/pharmacology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , SARS-CoV-2/enzymology , Viral Proteins/antagonists & inhibitors , Viral Proteins/metabolism , COVID-19/virology , Cryoelectron Microscopy , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Guanosine Monophosphate/chemistry , Guanosine Monophosphate/pharmacology , Humans , RNA-Dependent RNA Polymerase/chemistry , RNA-Dependent RNA Polymerase/genetics , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , Viral Proteins/genetics
4.
J Med Chem ; 64(19): 14332-14343, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1621195

ABSTRACT

In addition to a variety of viral-glycoprotein receptors (e.g., heparan sulfate, Niemann-Pick C1, etc.), dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), from the C-type lectin receptor family, plays one of the most important pathogenic functions for a wide range of viruses (e.g., Ebola, human cytomegalovirus (HCMV), HIV-1, severe acute respiratory syndrome coronavirus 2, etc.) that invade host cells before replication; thus, its inhibition represents a relevant extracellular antiviral therapy. We report two novel p-tBu-calixarene glycoclusters 1 and 2, bearing tetrahydroxamic acid groups, which exhibit micromolar inhibition of soluble DC-SIGN binding and provide nanomolar IC50 inhibition of both DC-SIGN-dependent Jurkat cis-cell infection by viral particle pseudotyped with Ebola virus glycoprotein and the HCMV-gB-recombinant glycoprotein interaction with monocyte-derived dendritic cells expressing DC-SIGN. A unique cooperative involvement of sugar, linker, and calixarene core is likely behind the strong avidity of DC-SIGN for these low-valent systems. We claim herein new promising candidates for the rational development of a large spectrum of antiviral therapeutics.


Subject(s)
Calixarenes/chemistry , Cell Adhesion Molecules/antagonists & inhibitors , Glycoconjugates/metabolism , Glycoproteins/antagonists & inhibitors , Hydroxamic Acids/chemistry , Lectins, C-Type/antagonists & inhibitors , Phenols/chemistry , Receptors, Cell Surface/antagonists & inhibitors , Viral Proteins/antagonists & inhibitors , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Cell Adhesion Molecules/metabolism , Cell Line , Cytomegalovirus/metabolism , Dendritic Cells/cytology , Dendritic Cells/metabolism , Ebolavirus/physiology , Glycoconjugates/chemistry , Glycoconjugates/pharmacology , Glycoproteins/genetics , Glycoproteins/metabolism , Humans , Jurkat Cells , Lectins, C-Type/metabolism , Models, Biological , Protein Binding , Receptors, Cell Surface/metabolism , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Viral Proteins/genetics , Viral Proteins/metabolism
5.
Biochem Soc Trans ; 50(1): 151-165, 2022 02 28.
Article in English | MEDLINE | ID: covidwho-1617010

ABSTRACT

SARS-CoV-2, the coronavirus responsible for the current COVID-19 pandemic, encodes two proteases, 3CLpro and PLpro, two of the main antiviral research targets. Here we provide an overview of the structures and functions of 3CLpro and PLpro and examine strategies of structure-based drug designing and drug repurposing against these proteases. Rational structure-based drug design enables the generation of potent and target-specific antivirals. Drug repurposing offers an attractive prospect with an accelerated turnaround. Thus far, several protease inhibitors have been identified, and some candidates are undergoing trials that may well prove to be effective antivirals against SARS-CoV-2.


Subject(s)
Drug Repositioning , Protease Inhibitors/pharmacology , SARS-CoV-2/enzymology , Viral Proteins/antagonists & inhibitors , Antiviral Agents/pharmacology , Drug Design , Humans , Peptide Hydrolases
6.
Molecules ; 26(24)2021 Dec 09.
Article in English | MEDLINE | ID: covidwho-1572567

ABSTRACT

COVID-19 is the name of the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that occurred in 2019. The virus-host-specific interactions, molecular targets on host cell deaths, and the involved signaling are crucial issues, which become potential targets for treatment. Spike protein, angiotensin-converting enzyme 2 (ACE2), cathepsin L-cysteine peptidase, transmembrane protease serine 2 (TMPRSS2), nonstructural protein 1 (Nsp1), open reading frame 7a (ORF7a), viral main protease (3C-like protease (3CLpro) or Mpro), RNA dependent RNA polymerase (RdRp) (Nsp12), non-structural protein 13 (Nsp13) helicase, and papain-like proteinase (PLpro) are molecules associated with SARS-CoV infection and propagation. SARS-CoV-2 can induce host cell death via five kinds of regulated cell death, i.e., apoptosis, necroptosis, pyroptosis, autophagy, and PANoptosis. The mechanisms of these cell deaths are well established and can be disrupted by synthetic small molecules or natural products. There are a variety of compounds proven to play roles in the cell death inhibition, such as pan-caspase inhibitor (z-VAD-fmk) for apoptosis, necrostatin-1 for necroptosis, MCC950, a potent and specific inhibitor of the NLRP3 inflammasome in pyroptosis, and chloroquine/hydroxychloroquine, which can mitigate the corresponding cell death pathways. However, NF-κB signaling is another critical anti-apoptotic or survival route mediated by SARS-CoV-2. Such signaling promotes viral survival, proliferation, and inflammation by inducing the expression of apoptosis inhibitors such as Bcl-2 and XIAP, as well as cytokines, e.g., TNF. As a result, tiny natural compounds functioning as proteasome inhibitors such as celastrol and curcumin can be used to modify NF-κB signaling, providing a responsible method for treating SARS-CoV-2-infected patients. The natural constituents that aid in inhibiting viral infection, progression, and amplification of coronaviruses are also emphasized, which are in the groups of alkaloids, flavonoids, terpenoids, diarylheptanoids, and anthraquinones. Natural constituents derived from medicinal herbs have anti-inflammatory and antiviral properties, as well as inhibitory effects, on the viral life cycle, including viral entry, replication, assembly, and release of COVID-19 virions. The phytochemicals contain a high potential for COVID-19 treatment. As a result, SARS-CoV-2-infected cell death processes and signaling might be of high efficacy for therapeutic targeting effects and yielding encouraging outcomes.


Subject(s)
COVID-19/drug therapy , Cell Death/drug effects , Drug Discovery/methods , Molecular Targeted Therapy/methods , SARS-CoV-2/drug effects , Amino Acid Chloromethyl Ketones/pharmacology , Antiviral Agents/pharmacology , Apoptosis/drug effects , Furans/pharmacology , Humans , Hydroxychloroquine/pharmacology , Imidazoles/pharmacology , Indenes/pharmacology , Indoles/pharmacology , Necroptosis/drug effects , Phytochemicals/pharmacology , Pyroptosis/drug effects , SARS-CoV-2/metabolism , Signal Transduction/drug effects , Sulfonamides/pharmacology , Viral Proteins/antagonists & inhibitors
7.
J Med Virol ; 94(4): 1373-1390, 2022 04.
Article in English | MEDLINE | ID: covidwho-1568201

ABSTRACT

In this era, broad-spectrum prodrugs with anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) activities are gaining considerable attention owing to their potential clinical benefits and role in combating the fast-spreading coronavirus disease 2019 (COVID-19) pandemic. The last 2 years have seen a surge of reports on various broad-spectrum prodrugs against SARS-CoV-2, and in in vitro studies, animal models, and clinical practice. Currently, only remdesivir (with many controversies and limitations) has been approved by the U.S. FDA for the treatment of SARS-CoV-2 infection, and additional potent anti-SARS-CoV-2 drugs are urgently required to enrich the defense arsenals. The world has ubiquitously grappled with the COVID-19 pandemic, and the availability of broad-spectrum prodrugs provides great hope for us to subdue this global threat. This article reviews promising treatment strategies, antiviral mechanisms, potential benefits, and daunting clinical challenges of anti-SARS-CoV-2 agents to provide some important guidance for future clinical treatment.


Subject(s)
Antiviral Agents/pharmacology , Prodrugs/pharmacology , SARS-CoV-2/drug effects , Animals , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Anti-Infective Agents/therapeutic use , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , COVID-19/drug therapy , COVID-19/epidemiology , Humans , Prodrugs/chemistry , Prodrugs/therapeutic use , SARS-CoV-2/metabolism , Viral Proteins/antagonists & inhibitors
8.
Antiviral Res ; 196: 105209, 2021 12.
Article in English | MEDLINE | ID: covidwho-1520691

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative agent of Coronavirus Disease 2019 (COVID-19) pandemic. Despite intensive and global efforts to discover and develop novel antiviral therapies, only Remdesivir has been approved as a treatment for COVID-19. Therefore, effective antiviral therapeutics are still urgently needed to combat and halt the pandemic. Viral RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 demonstrates high potential as a reliable target for the development of antivirals. We previously developed a cell-based assay to assess the efficiency of compounds that target SARS-CoV-2 RdRp, as well as their tolerance to viral exoribonuclease-mediated proof-reading. In our previous study, we discovered that 2-((1H-indol-3-yl)thio)-N-phenyl-acetamides specifically targets the RdRp of both respiratory syncytial virus (RSV) and influenza A virus. Thus, we hypothesize that 2-((1H-indol-3-yl)thio)-N-phenyl-acetamides may also have the ability to inhibit SARS-CoV-2 replication by targeting its RdRp activity. In this research, we test a compound library containing 103 of 2-((1H-indol-3-yl)thio)-N-phenyl-acetamides against SARS-CoV-2 RdRp, using our cell-based assay. Among these compounds, the top five candidates strongly inhibit SARS-CoV-2 RdRp activity while exhibiting low cytotoxicity and resistance to viral exoribonuclease. Compound 6-72-2a is the most promising candidate with the lowest EC50 value of 1.41 µM and highest selectivity index (CC50/EC50) (above 70.92). Furthermore, our data suggests that 4-46b and 6-72-2a also inhibit the replication of HCoV-OC43 and HCoV-NL63 virus in a dose-dependent manner. Compounds 4-46b and 6-72-2a exhibit EC50 values of 1.13 µM and 0.94 µM, respectively, on HCoV-OC43 viral replication. However, higher concentrations of these compounds are needed to effectively block HCoV-NL63 replication. Together, our findings successfully identified 4-46b and 6-72-2a as promising inhibitors against SARS-CoV-2 RdRp.


Subject(s)
Acetamides/pharmacology , COVID-19/drug therapy , RNA-Dependent RNA Polymerase , Antiviral Agents/pharmacology , Drug Delivery Systems , Humans , RNA, Viral/biosynthesis , RNA-Dependent RNA Polymerase/antagonists & inhibitors , RNA-Dependent RNA Polymerase/drug effects , SARS-CoV-2/drug effects , Viral Proteins/antagonists & inhibitors , Viral Proteins/drug effects , Virus Replication/drug effects
9.
Int J Mol Sci ; 22(20)2021 Oct 15.
Article in English | MEDLINE | ID: covidwho-1470891

ABSTRACT

SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2, represents a new pathogen from the family of Coronaviridae that caused a global pandemic of COVID-19 disease. In the absence of effective antiviral drugs, research of novel therapeutic targets such as SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) becomes essential. This viral protein is without a human counterpart and thus represents a unique prospective drug target. However, in vitro biological evaluation testing on RdRp remains difficult and is not widely available. Therefore, we prepared a database of commercial small-molecule compounds and performed an in silico high-throughput virtual screening on the active site of the SARS-CoV-2 RdRp using ensemble docking. We identified a novel thioether-amide or guanidine-linker class of potential RdRp inhibitors and calculated favorable binding free energies of representative hits by molecular dynamics simulations coupled with Linear Interaction Energy calculations. This innovative procedure maximized the respective phase-space sampling and yielded non-covalent inhibitors representing small optimizable molecules that are synthetically readily accessible, commercially available as well as suitable for further biological evaluation and mode of action studies.


Subject(s)
Antiviral Agents/chemistry , Enzyme Inhibitors/chemistry , RNA-Dependent RNA Polymerase/antagonists & inhibitors , SARS-CoV-2/enzymology , Viral Proteins/antagonists & inhibitors , Amides/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Binding Sites , COVID-19/drug therapy , COVID-19/virology , Catalytic Domain , Databases, Chemical , Drug Design , Enzyme Inhibitors/metabolism , Enzyme Inhibitors/therapeutic use , Guanidine/chemistry , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2/isolation & purification , Structure-Activity Relationship , Sulfides/chemistry , Thermodynamics , Viral Proteins/metabolism
10.
Eur J Med Chem ; 221: 113494, 2021 Oct 05.
Article in English | MEDLINE | ID: covidwho-1446590

ABSTRACT

In the search for new anti-influenza virus (IV) compounds, we have identified the 1,2,4-triazolo[1,5-a]pyrimidine (TZP) as a very suitable scaffold to obtain compounds able to disrupt IV RNA-dependent RNA polymerase (RdRP) PA-PB1 subunits heterodimerization. In this work, in order to acquire further SAR insights for this class of compounds and identify more potent derivatives, we designed and synthesized additional series of analogues to investigate the role of the substituents around the TZP core. To this aim, we developed four facile and efficient one-step procedures for the synthesis of 5-phenyl-, 6-phenyl- and 7-phenyl-2-amino-[1,2,4]triazolo[1,5-a]pyrimidines, and 2-amino-5-phenyl-[1,2,4]triazolo[1,5-a]pyrimidin-7-ol. Two analogues having the ethyl carboxylate moiety at the C-2 position of the TZP were also prepared in good yields. Then, the scaffolds herein synthesized and two previous scaffolds were functionalized and evaluated for their anti-IAV activity, leading to the identification of compound 22 that showed both anti-PA-PB1 (IC50 = 19.5 µM) and anti-IAV activity (EC50 = 16 µM) at non-toxic concentrations, thus resulting among the most active TZP derivatives reported to date by us. A selection of the synthesized compounds, along with a set of in-house available analogues, was also tested against SARS-CoV-2. The most promising compound 49 from this series displayed an EC50 value of 34.47 µM, highlighting the potential of the TPZ scaffold in the search for anti-CoV agents.


Subject(s)
Antiviral Agents/pharmacology , Protein Multimerization/drug effects , Pyrimidines/pharmacology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Triazoles/pharmacology , Viral Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemical synthesis , Chlorocebus aethiops , Dogs , Drug Design , HEK293 Cells , Humans , Influenza A virus/drug effects , Madin Darby Canine Kidney Cells , Microbial Sensitivity Tests , Pyrimidines/chemical synthesis , SARS-CoV-2/drug effects , Triazoles/chemical synthesis , Vero Cells
11.
Molecules ; 26(19)2021 Sep 24.
Article in English | MEDLINE | ID: covidwho-1438674

ABSTRACT

The COVID-19 pandemic needs no introduction at present. Only a few treatments are available for this disease, including remdesivir and favipiravir. Accordingly, the pharmaceutical industry is striving to develop new treatments for COVID-19. Molnupiravir, an orally active RdRp inhibitor, is in a phase 3 clinical trial against COVID-19. The objective of this review article is to enlighten the researchers working on COVID-19 about the discovery, recent developments, and patents related to molnupiravir. Molnupiravir was originally developed for the treatment of influenza at Emory University, USA. However, this drug has also demonstrated activity against a variety of viruses, including SARS-CoV-2. Now it is being jointly developed by Emory University, Ridgeback Biotherapeutics, and Merck to treat COVID-19. The published clinical data indicate a good safety profile, tolerability, and oral bioavailability of molnupiravir in humans. The patient-compliant oral dosage form of molnupiravir may hit the market in the first or second quarter of 2022. The patent data of molnupiravir revealed its granted compound patent and process-related patent applications. We also anticipate patent filing related to oral dosage forms, inhalers, and a combination of molnupiravir with marketed drugs like remdesivir, favipiravir, and baricitinib. The current pandemic demands a patient compliant, safe, tolerable, and orally effective COVID-19 treatment. The authors believe that molnupiravir meets these requirements and is a breakthrough COVID-19 treatment.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , Cytidine/analogs & derivatives , Drug Discovery , Hydroxylamines/therapeutic use , SARS-CoV-2/drug effects , Administration, Oral , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/chemistry , Clinical Trials as Topic , Cytidine/administration & dosage , Cytidine/chemistry , Cytidine/therapeutic use , Humans , Hydroxylamines/administration & dosage , Hydroxylamines/chemistry , Patents as Topic , RNA-Directed DNA Polymerase/metabolism , Reverse Transcriptase Inhibitors/administration & dosage , Reverse Transcriptase Inhibitors/chemistry , Reverse Transcriptase Inhibitors/therapeutic use , SARS-CoV-2/enzymology , Viral Proteins/antagonists & inhibitors , Viral Proteins/metabolism
12.
STAR Protoc ; 2(3): 100793, 2021 09 17.
Article in English | MEDLINE | ID: covidwho-1368796

ABSTRACT

This protocol describes an in vitro fluorogenic assay to measure the proteolytic activity and identify inhibitors of Mpro, the main protease produced by SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2). Studies to identify potential inhibitors of Mpro mainly rely on in silico molecular dynamics simulations or on FRET (Fluorescence Resonance Energy Transfer) substrates. The protocol is based on an aminomethyl coumarin substrate. High sensitivity, specificity, and an easily detectable fluorescent read-out are the advantages offered by this rapid assay, which allows high throughput screening of new Mpro inhibitors.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus 3C Proteases/antagonists & inhibitors , Fluorescence Resonance Energy Transfer/methods , Protease Inhibitors/pharmacology , SARS-CoV-2/enzymology , Viral Proteins/antagonists & inhibitors , COVID-19/metabolism , COVID-19/virology , Coronavirus 3C Proteases/metabolism , Coumarins/metabolism , Drug Discovery , High-Throughput Screening Assays , Humans , In Vitro Techniques
13.
Biochem Biophys Res Commun ; 570: 21-25, 2021 09 17.
Article in English | MEDLINE | ID: covidwho-1309162

ABSTRACT

Natto, a traditional Japanese fermented soybean food, is well known to be nutritious and beneficial for health. In this study, we examined whether natto impairs infection by viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as bovine herpesvirus 1 (BHV-1). Interestingly, our results show that both SARS-CoV-2 and BHV-1 treated with a natto extract were fully inhibited infection to the cells. We also found that the glycoprotein D of BHV-1 was shown to be degraded by Western blot analysis and that a recombinant SARS-CoV-2 receptor-binding domain (RBD) was proteolytically degraded when incubated with the natto extract. In addition, RBD protein carrying a point mutation (UK variant N501Y) was also degraded by the natto extract. When the natto extract was heated at 100 °C for 10 min, the ability of both SARS-CoV-2 and BHV-1 to infect to the cells was restored. Consistent with the results of the heat inactivation, a serine protease inhibitor inhibited anti-BHV-1 activity caused by the natto extract. Thus, our findings provide the first evidence that the natto extract contains a protease(s) that inhibits viral infection through the proteolysis of the viral proteins.


Subject(s)
COVID-19/drug therapy , Plant Extracts/pharmacology , SARS-CoV-2/drug effects , Soy Foods , Soybeans/chemistry , Animals , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , Cattle , Cells, Cultured , Chlorocebus aethiops , Herpesviridae Infections/drug therapy , Herpesviridae Infections/metabolism , Herpesviridae Infections/pathology , Herpesviridae Infections/virology , Herpesvirus 1, Bovine/drug effects , Herpesvirus 1, Bovine/isolation & purification , Herpesvirus 1, Bovine/pathogenicity , Humans , Plant Extracts/chemistry , SARS-CoV-2/isolation & purification , SARS-CoV-2/pathogenicity , Viral Proteins/antagonists & inhibitors , Viral Proteins/metabolism
14.
Eur J Med Chem ; 221: 113494, 2021 Oct 05.
Article in English | MEDLINE | ID: covidwho-1291451

ABSTRACT

In the search for new anti-influenza virus (IV) compounds, we have identified the 1,2,4-triazolo[1,5-a]pyrimidine (TZP) as a very suitable scaffold to obtain compounds able to disrupt IV RNA-dependent RNA polymerase (RdRP) PA-PB1 subunits heterodimerization. In this work, in order to acquire further SAR insights for this class of compounds and identify more potent derivatives, we designed and synthesized additional series of analogues to investigate the role of the substituents around the TZP core. To this aim, we developed four facile and efficient one-step procedures for the synthesis of 5-phenyl-, 6-phenyl- and 7-phenyl-2-amino-[1,2,4]triazolo[1,5-a]pyrimidines, and 2-amino-5-phenyl-[1,2,4]triazolo[1,5-a]pyrimidin-7-ol. Two analogues having the ethyl carboxylate moiety at the C-2 position of the TZP were also prepared in good yields. Then, the scaffolds herein synthesized and two previous scaffolds were functionalized and evaluated for their anti-IAV activity, leading to the identification of compound 22 that showed both anti-PA-PB1 (IC50 = 19.5 µM) and anti-IAV activity (EC50 = 16 µM) at non-toxic concentrations, thus resulting among the most active TZP derivatives reported to date by us. A selection of the synthesized compounds, along with a set of in-house available analogues, was also tested against SARS-CoV-2. The most promising compound 49 from this series displayed an EC50 value of 34.47 µM, highlighting the potential of the TPZ scaffold in the search for anti-CoV agents.


Subject(s)
Antiviral Agents/pharmacology , Protein Multimerization/drug effects , Pyrimidines/pharmacology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Triazoles/pharmacology , Viral Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemical synthesis , Chlorocebus aethiops , Dogs , Drug Design , HEK293 Cells , Humans , Influenza A virus/drug effects , Madin Darby Canine Kidney Cells , Microbial Sensitivity Tests , Pyrimidines/chemical synthesis , SARS-CoV-2/drug effects , Triazoles/chemical synthesis , Vero Cells
15.
Viruses ; 13(7)2021 06 24.
Article in English | MEDLINE | ID: covidwho-1289017

ABSTRACT

Arenaviruses and coronaviruses include several human pathogenic viruses, such as Lassa virus, Lymphocytic choriomeningitis virus (LCMV), SARS-CoV, MERS-CoV, and SARS-CoV-2. Although these viruses belong to different virus families, they possess a common motif, the DED/EDh motif, known as an exonuclease (ExoN) motif. In this study, proof-of-concept studies, in which the DED/EDh motif in these viral proteins, NP for arenaviruses, and nsp14 for coronaviruses, could be a drug target, were performed. Docking simulation studies between two structurally different chemical compounds, ATA and PV6R, and the DED/EDh motifs in these viral proteins indicated that these compounds target DED/EDh motifs. The concentration which exhibited modest cell toxicity was used with these compounds to treat LCMV and SARS-CoV-2 infections in two different cell lines, A549 and Vero 76 cells. Both ATA and PV6R inhibited the post-entry step of LCMV and SARS-CoV-2 infection. These studies strongly suggest that DED/EDh motifs in these viral proteins could be a drug target to combat two distinct viral families, arenaviruses and coronaviruses.


Subject(s)
Antiviral Agents/pharmacology , Exoribonucleases/antagonists & inhibitors , Lymphocytic choriomeningitis virus/drug effects , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Proteins/antagonists & inhibitors , Virus Replication/drug effects , A549 Cells , Amino Acid Motifs , Animals , Chlorocebus aethiops , Drug Discovery , Humans , Molecular Docking Simulation , Vero Cells
16.
Pharmacol Rep ; 73(6): 1765-1780, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1245804

ABSTRACT

BACKGROUND: The new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified at the end of 2019. Despite growing understanding of SARS-CoV-2 in virology as well as many molecular studies, except remdesivir, no specific anti-SARS-CoV-2 drug has been officially approved. METHODS: In the present study molecular docking technique was applied to test binding affinity of ciprofloxacin and levofloxacin-two commercially available fluoroquinolones, to SARS-CoV-2 S-, E- and TMPRSS2 proteins, RNA-dependent RNA polymerase and papain-like protease (PLPRO). Chloroquine and dexamethasone were used as reference positive controls. RESULTS: When analyzing the molecular docking data it was noticed that ciprofloxacin and levofloxacin possess lower binding energy with S protein as compared to the references. In the case of TMPRSS2 protein and PLPRO protease the best docked ligand was levofloxacin and in the case of E proteins and RNA-dependent RNA polymerase the best docked ligands were levofloxacin and dexamethasone. Moreover, a molecular dynamics study also reveals that ciprofloxacin and levofloxacin form a stable complex with E- and TMPRSS2 proteins, RNA polymerase and papain-like protease (PLPRO). CONCLUSIONS: The revealed data indicate that ciprofloxacin and levofloxacin could interact and potentially inhibit crucial SARS-CoV-2 proteins.


Subject(s)
Anti-Infective Agents/chemistry , Ciprofloxacin/chemistry , Levofloxacin/chemistry , Viral Proteins/antagonists & inhibitors , Binding Sites , COVID-19/drug therapy , Computer Simulation , Coronavirus Papain-Like Proteases/antagonists & inhibitors , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , RNA-Dependent RNA Polymerase/antagonists & inhibitors , SARS-CoV-2 , Serine Endopeptidases
17.
Sci Rep ; 11(1): 10290, 2021 05 13.
Article in English | MEDLINE | ID: covidwho-1228274

ABSTRACT

As the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic engulfs millions worldwide, the quest for vaccines or drugs against the virus continues. The helicase protein of SARS-CoV-2 represents an attractive target for drug discovery since inhibition of helicase activity can suppress viral replication. Using in silico approaches, we have identified drugs that interact with SARS-CoV-2 helicase based on the presence of amino acid arrangements matching binding sites of drugs in previously annotated protein structures. The drugs exhibiting an RMSD of ≤ 3.0 Å were further analyzed using molecular docking, molecular dynamics (MD) simulation, and post-MD analyses. Using these approaches, we found 12 drugs that showed strong interactions with SARS-CoV-2 helicase amino acids. The analyses were performed using the recently available SARS-CoV-2 helicase structure (PDB ID: 5RL6). Based on the MM-GBSA approach, out of the 12 drugs, two drugs, namely posaconazole and grazoprevir, showed the most favorable binding energy, - 54.8 and - 49.1 kcal/mol, respectively. Furthermore, of the amino acids found conserved among all human coronaviruses, 10/11 and 10/12 were targeted by, respectively, grazoprevir and posaconazole. These residues are part of the crucial DEAD-like helicase C and DEXXQc_Upf1-like/ DEAD-like helicase domains. Strong interactions of posaconazole and grazoprevir with conserved amino acids indicate that the drugs can be potent against SARS-CoV-2. Since the amino acids are conserved among the human coronaviruses, the virus is unlikely to develop resistance mutations against these drugs. Since these drugs are already in use, they may be immediately repurposed for SARS-CoV-2 therapy.


Subject(s)
Amides/pharmacology , Carbamates/pharmacology , Cyclopropanes/pharmacology , Drug Repositioning , Enzyme Inhibitors/pharmacology , Quinoxalines/pharmacology , RNA Helicases/antagonists & inhibitors , SARS-CoV-2/enzymology , Sulfonamides/pharmacology , Triazoles/pharmacology , Antiviral Agents/pharmacology , COVID-19/drug therapy , Drug Repositioning/methods , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Domains/drug effects , RNA Helicases/chemistry , RNA Helicases/metabolism , SARS-CoV-2/drug effects , Viral Proteins/antagonists & inhibitors , Viral Proteins/chemistry , Viral Proteins/metabolism
18.
Molecules ; 26(9)2021 Apr 29.
Article in English | MEDLINE | ID: covidwho-1217101

ABSTRACT

There is an urgent need for specific antiviral treatments directed against SARS-CoV-2 to prevent the most severe forms of COVID-19. By drug repurposing, affordable therapeutics could be supplied worldwide in the present pandemic context. Targeting the nucleoprotein N of the SARS-CoV-2 coronavirus could be a strategy to impede viral replication and possibly other essential functions associated with viral N. The antiviral properties of naproxen, a non-steroidal anti-inflammatory drug (NSAID) that was previously demonstrated to be active against Influenza A virus, were evaluated against SARS-CoV-2. Intrinsic fluorescence spectroscopy, fluorescence anisotropy, and dynamic light scattering assays demonstrated naproxen binding to the nucleoprotein of SARS-Cov-2 as predicted by molecular modeling. Naproxen impeded recombinant N oligomerization and inhibited viral replication in infected cells. In VeroE6 cells and reconstituted human primary respiratory epithelium models of SARS-CoV-2 infection, naproxen specifically inhibited viral replication and protected the bronchial epithelia against SARS-CoV-2-induced damage. No inhibition of viral replication was observed with paracetamol or the COX-2 inhibitor celecoxib. Thus, among the NSAID tested, only naproxen combined antiviral and anti-inflammatory properties. Naproxen addition to the standard of care could be beneficial in a clinical setting, as tested in an ongoing clinical study.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Antiviral Agents/pharmacology , COVID-19/drug therapy , Naproxen/pharmacology , Nucleoproteins/antagonists & inhibitors , SARS-CoV-2/drug effects , Viral Proteins/antagonists & inhibitors , Animals , Cell Line , Chlorocebus aethiops , Drug Repositioning , Humans , Molecular Docking Simulation , Nucleoproteins/metabolism , SARS-CoV-2/physiology , Vero Cells , Viral Proteins/metabolism , Virus Replication/drug effects
19.
Phytother Res ; 35(3): 1230-1236, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1171777

ABSTRACT

Several months ago, an outbreak of pneumonia of unknown aetiology was detected in Wuhan City (China) and the aetiological agent of the atypical pneumonia was isolated by the Chinese authorities as novel coronavirus (2019-nCoV or SARS-CoV-2). The WHO announced this new disease was to be known as "COVID-19." When looking for new antiviral compounds, knowledge of the main viral proteins is fundamental. The major druggable targets of SARS-CoV-2 include 3-chymotrypsin-like protease (3CLpro), papain-like protease (PLpro), RNA-dependent RNA polymerase, and spike (S) protein. Quercetin inhibits 3CLpro and PLpro with a docking binding energy corresponding to -6.25 and -4.62 kcal/mol, respectively. Quercetin has a theoretical, but significant, capability to interfere with SARS-CoV-2 replication, with the results showing this to be the fifth best compound out of 18 candidates. On the basis of the clinical COVID-19 manifestations, the multifaceted aspect of quercetin as both antiinflammatory and thrombin-inhibitory actions, should be taken into consideration.


Subject(s)
Quercetin/pharmacology , SARS-CoV-2/drug effects , Viral Proteins/antagonists & inhibitors , Antiviral Agents/pharmacology , COVID-19 , China , Humans , SARS-CoV-2/physiology , Virus Replication/drug effects
20.
Molecules ; 26(4)2021 Feb 10.
Article in English | MEDLINE | ID: covidwho-1110462

ABSTRACT

Currently, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) has infected people among all countries and is a pandemic as declared by the World Health Organization (WHO). SARS-CoVID-2 main protease is one of the therapeutic drug targets that has been shown to reduce virus replication, and its high-resolution 3D structures in complex with inhibitors have been solved. Previously, we had demonstrated the potential of natural compounds such as serine protease inhibitors eventually leading us to hypothesize that FDA-approved marine drugs have the potential to inhibit the biological activity of SARS-CoV-2 main protease. Initially, field-template and structure-activity atlas models were constructed to understand and explain the molecular features responsible for SARS-CoVID-2 main protease inhibitors, which revealed that Eribulin Mesylate, Plitidepsin, and Trabectedin possess similar characteristics related to SARS-CoVID-2 main protease inhibitors. Later, protein-ligand interactions are studied using ensemble molecular-docking simulations that revealed that marine drugs bind at the active site of the main protease. The three-dimensional reference interaction site model (3D-RISM) studies show that marine drugs displace water molecules at the active site, and interactions observed are favorable. These computational studies eventually paved an interest in further in vitro studies. Finally, these findings are new and indeed provide insights into the role of FDA-approved marine drugs, which are already in clinical use for cancer treatment as a potential alternative to prevent and treat infected people with SARS-CoV-2.


Subject(s)
Peptide Hydrolases/chemistry , Peptide Hydrolases/metabolism , SARS-CoV-2/physiology , Serine Proteinase Inhibitors/pharmacology , Catalytic Domain , Depsipeptides/chemistry , Depsipeptides/pharmacology , Drug Repositioning , Furans/chemistry , Furans/pharmacology , Humans , Ketones/chemistry , Ketones/pharmacology , Models, Molecular , Molecular Docking Simulation , Peptides, Cyclic , Quantitative Structure-Activity Relationship , SARS-CoV-2/drug effects , Serine Proteinase Inhibitors/chemistry , Trabectedin/chemistry , Trabectedin/pharmacology , Viral Proteins/antagonists & inhibitors , Virus Replication/drug effects
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