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1.
Sci Rep ; 12(1): 3860, 2022 03 09.
Article in English | MEDLINE | ID: covidwho-1799576

ABSTRACT

Non-structural protein 15 (Nsp15) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) forms a homo hexamer and functions as an endoribonuclease. Here, we propose that Nsp15 activity may be inhibited by preventing its hexamerization through drug binding. We first explored the stable conformation of the Nsp15 monomer as the global free energy minimum conformation in the free energy landscape using a combination of parallel cascade selection molecular dynamics (PaCS-MD) and the Markov state model (MSM), and found that the Nsp15 monomer forms a more open conformation with larger druggable pockets on the surface. Targeting the pockets with high druggability scores, we conducted ligand docking and identified compounds that tightly bind to the Nsp15 monomer. The top poses with Nsp15 were subjected to binding free energy calculations by dissociation PaCS-MD and MSM (dPaCS-MD/MSM), indicating the stability of the complexes. One of the identified pockets, which is distinctively bound by inosine analogues, may be an alternative binding site to stabilize viral RNA binding and/or an alternative catalytic site. We constructed a stable RNA structure model bound to both UTP and alternative binding sites, providing a reasonable proposed model of the Nsp15/RNA complex.


Subject(s)
Endoribonucleases/metabolism , RNA, Viral/chemistry , SARS-CoV-2/metabolism , Viral Nonstructural Proteins/metabolism , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Binding Sites , COVID-19/pathology , COVID-19/virology , Endoribonucleases/antagonists & inhibitors , Humans , Markov Chains , Molecular Docking Simulation , Molecular Dynamics Simulation , Nucleic Acid Conformation , Protein Multimerization , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Static Electricity , Viral Nonstructural Proteins/antagonists & inhibitors
2.
J Biomol Struct Dyn ; 40(1): 86-100, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1597994

ABSTRACT

Novel Coronavirus or SARS-CoV-2 outbreak has developed a pandemic condition all over the world. The virus is highly infectious and spreads by human to human local transmission mode. Till date, there is no vaccination or drugs been approved for the treatment by the World Health Organisation. Henceforth, the discovery of the potential drugs is an urgent and utmost requirement for the medical fraternity. Since, the side effects of plant-derived compounds will be lower compared to synthetic/chemical drugs. The Main protease (3CLpro or NSP5) and endoribonuclease (NSP15) proteins are necessity for viral replication and its survival in the host cell. In the present study, in-silico approach of drug development was used to search for potential antiviral plant-derived compounds as inhibitors against SARS-CoV-2 replication proteins. Eight plant-derived compounds of which the antiviral activity was known and available, and two reported drugs against SARS-CoV-2 selected for the molecular docking analysis. The docking results suggested that bisdemethoxycurcumin, demethoxycurcumin, scutellarin, quercetin and myricetin showed least binding energy, i.e., greater than -6.5 Kcal/mol against 3CLpro and endoribonuclease of SARS-CoV-2. Further studies of ADME-Tox and bioavailability of drugs were also performed that exhibited efficient parameters of drug likeness. Molecular dynamics simulation calculations were performed for the most negative binding affinity of the compound to evaluate the dynamic behavior,and stability of protein-ligand complex. Our findings suggest that these compounds could be potential inhibitors of SARS-CoV-2 main protease and endoribonuclease. However, further in-vitro and pre-clinical experiments would validate the potential inhibitors of SARS-CoV-2 proteins.


Subject(s)
Antiviral Agents , Phytochemicals/pharmacology , Protease Inhibitors , SARS-CoV-2 , Antiviral Agents/pharmacology , COVID-19 , Coronavirus 3C Proteases/antagonists & inhibitors , Endoribonucleases/antagonists & inhibitors , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Protease Inhibitors/pharmacology , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors
3.
Int J Mol Sci ; 22(19)2021 Oct 02.
Article in English | MEDLINE | ID: covidwho-1444233

ABSTRACT

Considering the current dramatic and fatal situation due to the high spreading of SARS-CoV-2 infection, there is an urgent unmet medical need to identify novel and effective approaches for prevention and treatment of Coronavirus disease (COVID 19) by re-evaluating and repurposing of known drugs. For this, tomatidine and patchouli alcohol have been selected as potential drugs for combating the virus. The hit compounds were subsequently docked into the active site and molecular docking analyses revealed that both drugs can bind the active site of SARS-CoV-2 3CLpro, PLpro, NSP15, COX-2 and PLA2 targets with a number of important binding interactions. To further validate the interactions of promising compound tomatidine, Molecular dynamics study of 100 ns was carried out towards 3CLpro, NSP15 and COX-2. This indicated that the protein-ligand complex was stable throughout the simulation period, and minimal backbone fluctuations have ensued in the system. Post dynamic MM-GBSA analysis of molecular dynamics data showed promising mean binding free energy 47.4633 ± 9.28, 51.8064 ± 8.91 and 54.8918 ± 7.55 kcal/mol, respectively. Likewise, in silico ADMET studies of the selected ligands showed excellent pharmacokinetic properties with good absorption, bioavailability and devoid of toxicity. Therefore, patchouli alcohol and especially, tomatidine may provide prospect treatment options against SARS-CoV-2 infection by potentially inhibiting virus duplication though more research is guaranteed and secured.


Subject(s)
Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus Papain-Like Proteases/antagonists & inhibitors , Endoribonucleases/antagonists & inhibitors , SARS-CoV-2/enzymology , Sesquiterpenes/pharmacology , Tomatine/analogs & derivatives , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/virology , Coronavirus 3C Proteases/metabolism , Coronavirus Papain-Like Proteases/metabolism , Endoribonucleases/metabolism , Enzyme Inhibitors/pharmacology , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , SARS-CoV-2/drug effects , Tomatine/pharmacology , Viral Nonstructural Proteins/metabolism
4.
Biochem J ; 478(13): 2465-2479, 2021 07 16.
Article in English | MEDLINE | ID: covidwho-1290092

ABSTRACT

SARS-CoV-2 is responsible for COVID-19, a human disease that has caused over 2 million deaths, stretched health systems to near-breaking point and endangered economies of countries and families around the world. Antiviral treatments to combat COVID-19 are currently lacking. Remdesivir, the only antiviral drug approved for the treatment of COVID-19, can affect disease severity, but better treatments are needed. SARS-CoV-2 encodes 16 non-structural proteins (nsp) that possess different enzymatic activities with important roles in viral genome replication, transcription and host immune evasion. One key aspect of host immune evasion is performed by the uridine-directed endoribonuclease activity of nsp15. Here we describe the expression and purification of nsp15 recombinant protein. We have developed biochemical assays to follow its activity, and we have found evidence for allosteric behaviour. We screened a custom chemical library of over 5000 compounds to identify nsp15 endoribonuclease inhibitors, and we identified and validated NSC95397 as an inhibitor of nsp15 endoribonuclease in vitro. Although NSC95397 did not inhibit SARS-CoV-2 growth in VERO E6 cells, further studies will be required to determine the effect of nsp15 inhibition on host immune evasion.


Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Drug Evaluation, Preclinical , Endoribonucleases/antagonists & inhibitors , SARS-CoV-2/enzymology , Small Molecule Libraries/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Allosteric Regulation , Animals , Chlorocebus aethiops , Endoribonucleases/isolation & purification , Endoribonucleases/metabolism , Enzyme Assays , Fluorescence , High-Throughput Screening Assays , In Vitro Techniques , Kinetics , Naphthoquinones/pharmacology , Reproducibility of Results , SARS-CoV-2/drug effects , SARS-CoV-2/growth & development , Small Molecule Libraries/chemistry , Solutions , Vero Cells , Viral Nonstructural Proteins/isolation & purification , Viral Nonstructural Proteins/metabolism
5.
PLoS One ; 16(4): e0250019, 2021.
Article in English | MEDLINE | ID: covidwho-1197380

ABSTRACT

SARS-CoV-2 has caused a global pandemic, and has taken over 1.7 million lives as of mid-December, 2020. Although great progress has been made in the development of effective countermeasures, with several pharmaceutical companies approved or poised to deliver vaccines to market, there is still an unmet need of essential antiviral drugs with therapeutic impact for the treatment of moderate-to-severe COVID-19. Towards this goal, a high-throughput assay was used to screen SARS-CoV-2 nsp15 uracil-dependent endonuclease (endoU) function against 13 thousand compounds from drug and lead repurposing compound libraries. While over 80% of initial hit compounds were pan-assay inhibitory compounds, three hits were confirmed as nsp15 endoU inhibitors in the 1-20 µM range in vitro. Furthermore, Exebryl-1, a ß-amyloid anti-aggregation molecule for Alzheimer's therapy, was shown to have antiviral activity between 10 to 66 µM, in Vero 76, Caco-2, and Calu-3 cells. Although the inhibitory concentrations determined for Exebryl-1 exceed those recommended for therapeutic intervention, our findings show great promise for further optimization of Exebryl-1 as an nsp15 endoU inhibitor and as a SARS-CoV-2 antiviral.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Drug Repositioning , Endoribonucleases/antagonists & inhibitors , SARS-CoV-2/drug effects , Small Molecule Libraries/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemistry , COVID-19/virology , Caco-2 Cells , Chlorocebus aethiops , Drug Repositioning/methods , Endoribonucleases/metabolism , High-Throughput Screening Assays/methods , Humans , Molecular Docking Simulation , SARS-CoV-2/metabolism , Small Molecule Libraries/chemistry , Vero Cells , Viral Nonstructural Proteins/metabolism
6.
J Med Chem ; 64(9): 5632-5644, 2021 05 13.
Article in English | MEDLINE | ID: covidwho-1193564

ABSTRACT

To develop antiviral therapeutics against human coronavirus (HCoV) infections, suitable coronavirus drug targets and corresponding lead molecules must be urgently identified. Here, we describe the discovery of a class of HCoV inhibitors acting on nsp15, a hexameric protein component of the viral replication-transcription complexes, endowed with immune evasion-associated endoribonuclease activity. Structure-activity relationship exploration of these 1,2,3-triazolo-fused betulonic acid derivatives yielded lead molecule 5h as a strong inhibitor (antiviral EC50: 0.6 µM) of HCoV-229E replication. An nsp15 endoribonuclease active site mutant virus was markedly less sensitive to 5h, and selected resistance to the compound mapped to mutations in the N-terminal part of HCoV-229E nsp15, at an interface between two nsp15 monomers. The biological findings were substantiated by the nsp15 binding mode for 5h, predicted by docking. Hence, besides delivering a distinct class of inhibitors, our study revealed a druggable pocket in the nsp15 hexamer with relevance for anti-coronavirus drug development.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 229E, Human/drug effects , Coronavirus 229E, Human/enzymology , Endoribonucleases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Oleanolic Acid/analogs & derivatives , Viral Nonstructural Proteins/antagonists & inhibitors , Virus Replication/drug effects , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Cell Line , Dose-Response Relationship, Drug , Endoribonucleases/metabolism , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , Microbial Sensitivity Tests , Models, Molecular , Oleanolic Acid/chemical synthesis , Oleanolic Acid/chemistry , Oleanolic Acid/pharmacology , Viral Nonstructural Proteins/metabolism
7.
J Comput Chem ; 42(13): 897-907, 2021 05 15.
Article in English | MEDLINE | ID: covidwho-1130516

ABSTRACT

SARS-CoV and SARS-CoV-2 belong to the subfamily Coronaviridae and infect humans, they are constituted by four structural proteins: Spike glycoprotein (S), membrane (M), envelope (E) and nucleocapsid (N), and nonstructural proteins, such as Nsp15 protein which is exclusively present on nidoviruses and is absent in other RNA viruses, making it an ideal target in the field of drug design. A virtual screening strategy to search for potential drugs was proposed, using molecular docking to explore a library of approved drugs available in the DrugBank database in order to identify possible NSP15 inhibitors to treat Covid19 disease. We found from the docking analysis that the antiviral drugs: Paritaprevir and Elbasvir, currently both approved for hepatitis C treatment which showed some of the lowest free binding energy values were considered as repositioning drugs to combat SARS-CoV-2. Furthermore, molecular dynamics simulations of the Apo and Holo-Nsp15 systems were performed in order to get insights about the stability of these protein-ligand complexes.


Subject(s)
Antiviral Agents/pharmacology , Benzofurans/pharmacology , COVID-19/drug therapy , Cyclopropanes/pharmacology , Endoribonucleases/antagonists & inhibitors , Imidazoles/pharmacology , Lactams, Macrocyclic/pharmacology , Proline/analogs & derivatives , SARS-CoV-2/drug effects , Sulfonamides/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , COVID-19/virology , Drug Repositioning , Endoribonucleases/metabolism , Humans , Molecular Docking Simulation , Molecular Targeted Therapy , Proline/pharmacology , SARS-CoV-2/metabolism , Viral Nonstructural Proteins/metabolism
8.
Methods ; 195: 44-56, 2021 11.
Article in English | MEDLINE | ID: covidwho-1101546

ABSTRACT

Novel coronavirus SARS-CoV-2continues tospread rapidly worldwide and causing serious health and economic loss. In the absence of any effective treatment, various in-silico approaches are being explored towards the therapeutic discovery against COVID-19. Targeting multiple key enzymes of SARS-CoV-2 with a single potential drug could be an important in-silico strategy to tackle the therapeutic emergency. A number of Food and Drug Administration (FDA) approved drugs entered into clinical stages were originated from multi-target approaches with an increased rate, 16-21% between 2015 and 2017. In this study, we selected an FDA-approved library (Prestwick Chemical Library of 1520 compounds) and implemented in-silico virtual screening against multiple protein targets of SARS-CoV-2 on the Glide module of Schrödinger software (release 2020-1). Compounds were analyzed for their docking scores and the top-ranked against each targeted protein were further subjected to Molecular Dynamics (MD) simulations to assess the binding stability of ligand-protein complexes. A multi-targeting approach was optimized that enabled the analysis of several compounds' binding efficiency with more than one protein targets. It was demonstrated that Diosmin (6) showed the highest binding affinity towards multiple targets with binding free energy (kcal/mol) values of -63.39 (nsp3); -62.89 (nsp9); -31.23 (nsp12); and -65.58 (nsp15). Therefore, our results suggests that Diosmin (6) possesses multi-targeting capability, a potent inhibitor of various non-structural proteins of SARS-CoV-2, and thus it deserves further validation experiments before using as a therapeutic against COVID-19 disease.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Diosmin/pharmacology , Antiviral Agents/therapeutic use , COVID-19/virology , Coronavirus Papain-Like Proteases/antagonists & inhibitors , Coronavirus Papain-Like Proteases/metabolism , Coronavirus RNA-Dependent RNA Polymerase/antagonists & inhibitors , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Diosmin/therapeutic use , Drug Discovery , Endoribonucleases/antagonists & inhibitors , Endoribonucleases/metabolism , Humans , Ligands , Molecular Docking Simulation , Molecular Dynamics Simulation , RNA-Binding Proteins , SARS-CoV-2/metabolism , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism
9.
Food Chem ; 346: 128933, 2021 Jun 01.
Article in English | MEDLINE | ID: covidwho-1082161

ABSTRACT

Immensely aggravated situation of COVID-19 has pushed the scientific community towards developing novel therapeutics to fight the pandemic. Small molecules can possibly prevent the spreading infection by targeting specific vital components of the viral genome. Non-structural protein 15 (Nsp15) has emerged as a promising target for such inhibitor molecules. In this investigation, we docked bioactive molecules of tea onto the active site of Nsp15. Based on their docking scores, top three molecules (Barrigenol, Kaempferol, and Myricetin) were selected and their conformational behavior was analyzed via molecular dynamics simulations and MMPBSA calculations. The results indicated that the protein had well adapted the ligands in the binding pocket thereby forming stable complexes. These molecules displayed low binding energy during MMPBSA calculations, substantiating their strong association with Nsp15. The inhibitory potential of these molecules could further be examined by in-vivo and in-vitro investigations to validate their use as inhibitors against Nsp15 of SARS-CoV2.


Subject(s)
Antiviral Agents/pharmacology , Computer Simulation , Endoribonucleases/antagonists & inhibitors , Plant Extracts/pharmacology , Tea/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Catalytic Domain , Endoribonucleases/chemistry , Endoribonucleases/metabolism , Humans , Ligands , Molecular Dynamics Simulation , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism
10.
Commun Biol ; 4(1): 193, 2021 02 09.
Article in English | MEDLINE | ID: covidwho-1075259

ABSTRACT

SARS-CoV-2 Nsp15 is a uridine-specific endoribonuclease with C-terminal catalytic domain belonging to the EndoU family that is highly conserved in coronaviruses. As endoribonuclease activity seems to be responsible for the interference with the innate immune response, Nsp15 emerges as an attractive target for therapeutic intervention. Here we report the first structures with bound nucleotides and show how the enzyme specifically recognizes uridine moiety. In addition to a uridine site we present evidence for a second base binding site that can accommodate any base. The structure with a transition state analog, uridine vanadate, confirms interactions key to catalytic mechanisms. In the presence of manganese ions, the enzyme cleaves unpaired RNAs. This acquired knowledge was instrumental in identifying Tipiracil, an FDA approved drug that is used in the treatment of colorectal cancer, as a potential anti-COVID-19 drug. Using crystallography, biochemical, and whole-cell assays, we demonstrate that Tipiracil inhibits SARS-CoV-2 Nsp15 by interacting with the uridine binding pocket in the enzyme's active site. Our findings provide new insights for the development of uracil scaffold-based drugs.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/virology , Endoribonucleases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Pyrrolidines/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Thymine/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , A549 Cells , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Catalytic Domain , Crystallography, X-Ray , Endoribonucleases/chemistry , Endoribonucleases/metabolism , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacokinetics , Humans , Ligands , Models, Molecular , Protein Conformation , Pyrrolidines/chemistry , Pyrrolidines/pharmacokinetics , Thymine/chemistry , Thymine/pharmacokinetics , Uridine/metabolism , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism
11.
Arch Biochem Biophys ; 700: 108771, 2021 03 30.
Article in English | MEDLINE | ID: covidwho-1039239

ABSTRACT

In the current study, a structure-based virtual screening paradigm was used to screen a small molecular database against the Non-structural protein 15 (Nsp15) endoribonuclease of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 is the causative agent of the recent outbreak of coronavirus disease 2019 (COVID-19) which left the entire world locked down inside the home. A multi-step molecular docking study was performed against antiviral specific compounds (~8722) collected from the Asinex antiviral database. The less or non-interacting molecules were wiped out sequentially in the molecular docking. Further, MM-GBSA based binding free energy was estimated for 26 compounds which shows a high affinity towards the Nsp15. The drug-likeness and pharmacokinetic parameters of all 26 compounds were explored, and five molecules were found to have an acceptable pharmacokinetic profile. Overall, the Glide-XP docking score and Prime-MM-GBSA binding free energy of the selected molecules were explained strong interaction potentiality towards the Nsp15 endoribonuclease. The dynamic behavior of each molecule with Nsp15 was assessed using conventional molecular dynamics (MD) simulation. The MD simulation information was strongly favors the Nsp15 and each identified ligand stability in dynamic condition. Finally, from the MD simulation trajectories, the binding free energy was estimated using the MM-PBSA method. Hence, the proposed final five molecules might be considered as potential Nsp15 modulators for SARS-CoV-2 inhibition.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/virology , Endoribonucleases/antagonists & inhibitors , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , COVID-19/metabolism , Databases, Chemical , Drug Evaluation, Preclinical , Endoribonucleases/chemistry , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Humans , In Vitro Techniques , Ligands , Molecular Docking Simulation , Molecular Dynamics Simulation , Molecular Structure , User-Computer Interface , Viral Nonstructural Proteins/chemistry
12.
Phytomedicine ; 85: 153317, 2021 May.
Article in English | MEDLINE | ID: covidwho-741455

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) playing havoc across the globe caused 585,727 deaths and 13,616,593 confirmed cases so far as per World Health Organization data released till 17th July 2020. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) is responsible for causing this pandemic across different continents. It is not only impacting the world economy but also quarantined millions of people in their homes or hospitals. PURPOSE: At present, there is no Food and Drug Administration-approved drug or vaccine available to treat this disease. Still, people are trying various pre-existing medicines that are known to have anti-viral or anti-parasitic effects. In view of this, the present study aimed to study the binding potential of various phytochemicals present in multiple natural plant extract as a secondary metabolite to non-structural protein 15 (Nsp15) protein, a drug target known to play a crucial role in virulence of coronavirus. METHOD: Nsp15 protein was selected because it shows 89% similarity to the other SARS-CoV, which caused the earlier outbreak. The assumption is that inhibition of Nsp15 slowdowns the viral replication. Phytochemicals are selected as these are present in various plant parts (seed, flower, roots, etc.), which are used in different food cuisines in different geographical regions across the globe. The molecular docking approach was performed using two different software, i.e., Autodock, and Swissdock, to study the interaction of various phytochemicals with Nsp15 protein. Hydroxychloroquine is used as a positive control as it is used by medical professionals showing some positive effects in dealing with coronavirus. RESULTS: The present study demonstrated the binding potential of approximately 50 phytochemicals with Nsp15 and capable of inhibiting the viral replication, although in vitro and in vivo tests are required to confirm these findings. CONCLUSIONS: In conclusion, the present study successfully demonstrated the binding of phytochemicals such as sarsasapogenin, ursonic acid, curcumin, ajmalicine, novobiocin, silymarin and aranotin, piperine, gingerol, rosmarinic acid, and alpha terpinyl acetate to Nsp15 viral protein and they might play a key role in inhibiting SARS-CoV-2 replication.


Subject(s)
Antiviral Agents/pharmacology , Endoribonucleases/antagonists & inhibitors , Phytochemicals/pharmacology , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Virus Replication/drug effects , Molecular Docking Simulation , Molecular Dynamics Simulation , SARS-CoV-2/physiology , Software
13.
Ann Allergy Asthma Immunol ; 125(5): 503-504, 2020 11.
Article in English | MEDLINE | ID: covidwho-628802

Subject(s)
Adrenal Cortex Hormones/therapeutic use , Anti-Asthmatic Agents/therapeutic use , Asthma/drug therapy , Coronavirus Infections/prevention & control , Cytokine Release Syndrome/prevention & control , Dexamethasone/therapeutic use , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Administration, Inhalation , Angiotensin-Converting Enzyme 2 , Asthma/immunology , Asthma/pathology , Asthma/virology , Betacoronavirus/drug effects , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , COVID-19 , Coronavirus Infections/immunology , Coronavirus Infections/pathology , Coronavirus Infections/virology , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/pathology , Cytokine Release Syndrome/virology , Endoribonucleases/antagonists & inhibitors , Endoribonucleases/genetics , Endoribonucleases/immunology , Gene Expression Regulation/drug effects , Host-Pathogen Interactions/drug effects , Host-Pathogen Interactions/genetics , Host-Pathogen Interactions/immunology , Humans , Interleukin-6/antagonists & inhibitors , Interleukin-6/genetics , Interleukin-6/immunology , Interleukin-8/antagonists & inhibitors , Interleukin-8/genetics , Interleukin-8/immunology , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/immunology , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Receptors, Virus/antagonists & inhibitors , Receptors, Virus/genetics , Receptors, Virus/immunology , SARS-CoV-2 , Serine Endopeptidases/genetics , Serine Endopeptidases/immunology , Severity of Illness Index , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/immunology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/immunology
14.
J Virol ; 94(17)2020 08 17.
Article in English | MEDLINE | ID: covidwho-601769

ABSTRACT

Coronaviruses (CoVs) have repeatedly emerged from wildlife hosts and infected humans and livestock animals to cause epidemics with significant morbidity and mortality. CoVs infect various organs, including respiratory and enteric systems, as exemplified by newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The constellation of viral factors that contribute to developing enteric disease remains elusive. Here, we investigated CoV interferon antagonists for their contribution to enteric pathogenesis. Using an infectious clone of an enteric CoV, porcine epidemic diarrhea virus (icPEDV), we generated viruses with inactive versions of interferon antagonist nonstructural protein 1 (nsp1), nsp15, and nsp16 individually or combined into one virus designated icPEDV-mut4. Interferon-responsive PK1 cells were infected with these viruses and produced higher levels of interferon responses than were seen with wild-type icPEDV infection. icPEDV-mut4 elicited robust interferon responses and was severely impaired for replication in PK1 cells. To evaluate viral pathogenesis, piglets were infected with either icPEDV or icPEDV-mut4. While the icPEDV-infected piglets exhibited clinical disease, the icPEDV-mut4-infected piglets showed no clinical symptoms and exhibited normal intestinal pathology at day 2 postinfection. icPEDV-mut4 replicated in the intestinal tract, as revealed by detection of viral RNA in fecal swabs, with sequence analysis documenting genetic stability of the input strain. Importantly, icPEDV-mut4 infection elicited IgG and neutralizing antibody responses to PEDV. These results identify nsp1, nsp15, and nsp16 as virulence factors that contribute to the development of PEDV-induced diarrhea in swine. Inactivation of these CoV interferon antagonists is a rational approach for generating candidate vaccines to prevent disease and spread of enteric CoVs, including SARS-CoV-2.IMPORTANCE Emerging coronaviruses, including SARS-CoV-2 and porcine CoVs, can infect enterocytes, cause diarrhea, and be shed in the feces. New approaches are needed to understand enteric pathogenesis and to develop vaccines and therapeutics to prevent the spread of these viruses. Here, we exploited a reverse genetic system for an enteric CoV, porcine epidemic diarrhea virus (PEDV), and outline an approach of genetically inactivating highly conserved viral factors known to limit the host innate immune response to infection. Our report reveals that generating PEDV with inactive versions of three viral interferon antagonists, nonstructural proteins 1, 15, and 16, results in a highly attenuated virus that does not cause diarrhea in animals and elicits a neutralizing antibody response in virus-infected animals. This strategy may be useful for generating live attenuated vaccine candidates that prevent disease and fecal spread of enteric CoVs, including SARS-CoV-2.


Subject(s)
Coronavirus Infections/immunology , Coronavirus/immunology , Interferons/immunology , Porcine epidemic diarrhea virus/immunology , Vaccines, Attenuated/immunology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Betacoronavirus/immunology , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/prevention & control , Diarrhea/pathology , Diarrhea/virology , Disease Models, Animal , Endoribonucleases/antagonists & inhibitors , Feces/virology , Ileum/pathology , Immunity, Innate , Jejunum/pathology , Pandemics , Pneumonia, Viral/immunology , Porcine epidemic diarrhea virus/genetics , RNA, Viral , RNA-Dependent RNA Polymerase , SARS-CoV-2 , Swine , Swine Diseases/virology , Vero Cells , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/immunology
15.
J Allergy Clin Immunol ; 146(2): 330-331, 2020 08.
Article in English | MEDLINE | ID: covidwho-597639
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