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1.
J Med Virol ; 93(9): 5487-5504, 2021 09.
Article in English | MEDLINE | ID: covidwho-1733919

ABSTRACT

Along with the control and prevention of coronavirus disease 2019 transmission, infected animals might have potential to carry the virus to spark new outbreaks. However, very few studies explore the susceptibility of animals to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Viral attachment as a crucial step for cross-species infection requires angiotensin-converting enzyme 2 (ACE2) as a receptor and depends on TMPRSS2 protease activity. Here, we searched the genomes of metazoans from different classes using an extensive BLASTP survey and found ACE2 and TMPRSS2 occur in vertebrates, but some vertebrates lack Tmprss2. We identified 6 amino acids among 25 known human ACE2 residues are highly associated with the binding of ACE2 to SARS-CoV-2 (p value < .01) by Fisher exact test, and following this, calculated the probability of viral attachment within each species by the randomForest function from R randomForest library. Furthermore, we observed that Ace2 selected from seven animals based on the above analysis lack the hydrophobic contacts identified on human ACE2, indicating less affinity of SARS-CoV-2 to Ace2 in animals than humans. Finally, the alignment of 3D structure between human ACE2 and other animals by I-TASSER and TM-align displayed a reasonable structure for viral attachment within these species. Taken together, our data may shed light on the human-to-animal transmission of SARS-CoV-2.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/virology , Host-Pathogen Interactions , SARS-CoV-2/physiology , Serine Endopeptidases/metabolism , Vertebrates/metabolism , Angiotensin-Converting Enzyme 2/genetics , Animals , COVID-19/genetics , COVID-19/metabolism , Disease Susceptibility , Genetic Predisposition to Disease , Humans , Receptors, Virus/metabolism , SARS-CoV-2/classification , Serine Endopeptidases/genetics , Spike Glycoprotein, Coronavirus/metabolism , Vertebrates/genetics , Virus Attachment , Virus Internalization , Virus Release
2.
J Infect Dis ; 225(5): 810-819, 2022 03 02.
Article in English | MEDLINE | ID: covidwho-1722486

ABSTRACT

The pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not completely understood. SARS-CoV-2 infection frequently causes significant immune function consequences including reduced T cell numbers and enhanced T cell exhaustion that contribute to disease severity. The extent to which T cell effects are directly mediated through infection or indirectly result from infection of respiratory-associated cells is unclear. We show that primary human T cells express sufficient levels of angiotensin converting enzyme 2 (ACE-2), the SARS-CoV-2 receptor, to mediate viral binding and entry into T cells. We further show that T cells exposed to SARS-CoV-2 particles demonstrate reduced proliferation and apoptosis compared to uninfected controls, indicating that direct interaction of SARS-CoV-2 with T cells may alter T cell growth, activation, and survival. Regulation of T cell activation and/or turnover by SARS-CoV-2 may contribute to impaired T cell function observed in patients with severe disease.


Subject(s)
Angiotensin-Converting Enzyme 2 , COVID-19 , T-Lymphocytes/metabolism , Humans , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Virus Attachment
3.
J Med Virol ; 94(4): 1738-1744, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1718408

ABSTRACT

As the latest identified novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern (VOC), the influence of Omicron on our globe grows promptly. Compared with the last VOC (Delta variant), more mutations were identified, which may address the characteristics of Omicron. Considering these crucial mutations and their implications including an increase in transmissibility, COVID-19 severity, and reduction of efficacy of currently available diagnostics, vaccines, and therapeutics, Omicron has been classified as one of the VOC. Notably, 15 of these mutations reside in the receptor-binding domain of spike glycoprotein, which may alter transmissibility, infectivity, neutralizing antibody escape, and vaccine breakthrough cases of COVID-19. Therefore, our present study characterizes the mutational hotspots of the Omicron variant in comparison with the Delta variant of SARS-CoV-2. Furthermore, detailed information was analyzed to characterize the global perspective of Omicron, including transmission dynamic, effect on testing, and immunity, which shall promote the progress of the clinical application and basic research. Collectively, our data suggest that due to continuous variation in the spike glycoprotein sequences, the use of coronavirus-specific attachment inhibitors may not be the current choice of therapy for emerging SARS-CoV-2 VOCs. Hence, we need to proceed with a sense of urgency in this matter.


Subject(s)
SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/transmission , COVID-19 Testing , Humans , Immune Evasion/genetics , Mutation , Phylogeny , Prevalence , Protein Binding/genetics , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Vaccination , Virus Attachment
4.
Viruses ; 14(2)2022 02 17.
Article in English | MEDLINE | ID: covidwho-1703374

ABSTRACT

Coronaviruses (CoVs) are common among humans and many animals, causing respiratory or gastrointestinal diseases. Currently, only a few antiviral drugs against CoVs are available. Especially for SARS-CoV-2, new compounds for treatment of COVID-19 are urgently needed. In this study, we characterize the antiviral effects of two high-sulfated glycosaminoglycan (GAG) derivatives against SARS-CoV-2 and bovine coronaviruses (BCoV), which are both members of the Betacoronavirus genus. The investigated compounds are based on hyaluronan (HA) and chondroitin sulfate (CS) and exhibit a strong inhibitory effect against both CoVs. Yield assays were performed using BCoV-infected PT cells in the presence and absence of the compounds. While the high-sulfated HA (sHA3) led to an inhibition of viral growth early after infection, high-sulfated CS (sCS3) had a slightly smaller effect. Time of addition assays, where sHA3 and sCS3 were added to PT cells before, during or after infection, demonstrated an inhibitory effect during all phases of infection, whereas sHA3 showed a stronger effect even after virus absorbance. Furthermore, attachment analyses with prechilled PT cells revealed that virus attachment is not blocked. In addition, sHA3 and sCS3 inactivated BCoV by stable binding. Analysis by quantitative real-time RT PCR underlines the high potency of the inhibitors against BCoV, as well as B.1-lineage, Alpha and Beta SARS-CoV-2 viruses. Taken together, these results demonstrated that the two high-sulfated GAG derivatives exhibit low cytotoxicity and represent promising candidates for an anti-CoV therapy.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus Infections/veterinary , Coronavirus, Bovine/drug effects , Glycosaminoglycans/pharmacology , SARS-CoV-2/drug effects , Animals , COVID-19/drug therapy , Cattle , Cell Line , Chondroitin Sulfates/chemistry , Chondroitin Sulfates/pharmacology , Coronavirus Infections/drug therapy , Glycosaminoglycans/chemistry , Glycosaminoglycans/metabolism , Humans , Hyaluronic Acid/chemistry , Hyaluronic Acid/pharmacology , Sulfates/chemistry , Sulfates/pharmacology , Virus Attachment/drug effects
5.
Nat Commun ; 13(1): 1002, 2022 02 22.
Article in English | MEDLINE | ID: covidwho-1702683

ABSTRACT

The molecular events that permit the spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to bind and enter cells are important to understand for both fundamental and therapeutic reasons. Spike proteins consist of S1 and S2 domains, which recognize angiotensin-converting enzyme 2 (ACE2) receptors and contain the viral fusion machinery, respectively. Ostensibly, the binding of spike trimers to ACE2 receptors promotes dissociation of the S1 domains and exposure of the fusion machinery, although the molecular details of this process have yet to be observed. We report the development of bottom-up coarse-grained (CG) models consistent with cryo-electron tomography data, and the use of CG molecular dynamics simulations to investigate viral binding and S2 core exposure. We show that spike trimers cooperatively bind to multiple ACE2 dimers at virion-cell interfaces in a manner distinct from binding between soluble proteins, which processively induces S1 dissociation. We also simulate possible variant behavior using perturbed CG models, and find that ACE2-induced S1 dissociation is primarily sensitive to conformational state populations and the extent of S1/S2 cleavage, rather than ACE2 binding affinity. These simulations reveal an important concerted interaction between spike trimers and ACE2 dimers that primes the virus for membrane fusion and entry.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Receptors, Virus/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Algorithms , Angiotensin-Converting Enzyme 2/chemistry , COVID-19/virology , Host-Pathogen Interactions , Humans , Membrane Fusion , Molecular Dynamics Simulation , Protein Binding , Protein Domains , Protein Multimerization , Receptors, Virus/chemistry , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Virus Attachment , Virus Internalization
6.
PLoS Pathog ; 18(2): e1010343, 2022 02.
Article in English | MEDLINE | ID: covidwho-1690680

ABSTRACT

The continuous emergence of severe acute respiratory coronavirus 2 (SARS-CoV-2) variants and the increasing number of breakthrough infection cases among vaccinated people support the urgent need for research and development of antiviral drugs. Viral entry is an intriguing target for antiviral drug development. We found that diltiazem, a blocker of the L-type calcium channel Cav1.2 pore-forming subunit (Cav1.2 α1c) and an FDA-approved drug, inhibits the binding and internalization of SARS-CoV-2, and decreases SARS-CoV-2 infection in cells and mouse lung. Cav1.2 α1c interacts with SARS-CoV-2 spike protein and ACE2, and affects the attachment and internalization of SARS-CoV-2. Our finding suggests that diltiazem has potential as a drug against SARS-CoV-2 infection and that Cav1.2 α1c is a promising target for antiviral drug development for COVID-19.


Subject(s)
COVID-19 , Diltiazem/pharmacology , Lung/drug effects , SARS-CoV-2/drug effects , A549 Cells , Animals , COVID-19/drug therapy , COVID-19/pathology , COVID-19/virology , Cells, Cultured , Chlorocebus aethiops , Diltiazem/therapeutic use , Disease Models, Animal , Female , HEK293 Cells , HeLa Cells , Humans , Lung/pathology , Lung/virology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Transgenic , SARS-CoV-2/physiology , Vero Cells , Virus Attachment/drug effects , Virus Internalization/drug effects
7.
Viruses ; 14(2)2022 02 14.
Article in English | MEDLINE | ID: covidwho-1687052

ABSTRACT

The evolution of the SARS-CoV-2 virus during the COVID-19 pandemic was accompanied by the emergence of new heavily mutated viral variants with increased infectivity and/or resistance to detection by the human immune system. To respond to the urgent need for advanced methods and materials to empower a better understanding of the mechanisms of virus's adaptation to human host cells and to the immuno-resistant human population, we suggested using recombinant filamentous bacteriophages, displaying on their surface foreign peptides termed "mimotopes", which mimic the structure of viral receptor-binding sites on the viral spike protein and can serve as molecular probes in the evaluation of molecular mechanisms of virus infectivity. In opposition to spike-binding antibodies that are commonly used in studying the interaction of the ACE2 receptor with SARS-CoV-2 variants in vitro, phage spike mimotopes targeted to other cellular receptors would allow discovery of their role in viral infection in vivo using cell culture, tissue, organs, or the whole organism. Phage mimotopes of the SARS-CoV-2 Spike S1 protein have been developed using a combination of phage display and molecular mimicry concepts, termed here "phage mimicry", supported by bioinformatics methods. The key elements of the phage mimicry concept include: (1) preparation of a collection of p8-type (landscape) phages, which interact with authentic active receptors of live human cells, presumably mimicking the binding interactions of human coronaviruses such as SARS-CoV-2 and its variants; (2) discovery of closely related amino acid clusters with similar 3D structural motifs on the surface of natural ligands (FGF1 and NRP1), of the model receptor of interest FGFR and the S1 spike protein; and (3) an ELISA analysis of the interaction between candidate phage mimotopes with FGFR3 (a potential alternative receptor) in comparison with ACE2 (the authentic receptor).


Subject(s)
Bacteriophages/genetics , Cell Surface Display Techniques/methods , Molecular Mimicry , Receptors, Cell Surface/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Bacteriophages/metabolism , Binding Sites , Humans , Protein Binding , Receptors, Cell Surface/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Virus Attachment
8.
Cell ; 185(5): 860-871.e13, 2022 03 03.
Article in English | MEDLINE | ID: covidwho-1650841

ABSTRACT

The SARS-CoV-2 Omicron variant with increased fitness is spreading rapidly worldwide. Analysis of cryo-EM structures of the spike (S) from Omicron reveals amino acid substitutions forging interactions that stably maintain an active conformation for receptor recognition. The relatively more compact domain organization confers improved stability and enhances attachment but compromises the efficiency of the viral fusion step. Alterations in local conformation, charge, and hydrophobic microenvironments underpin the modulation of the epitopes such that they are not recognized by most NTD- and RBD-antibodies, facilitating viral immune escape. Structure of the Omicron S bound with human ACE2, together with the analysis of sequence conservation in ACE2 binding region of 25 sarbecovirus members, as well as heatmaps of the immunogenic sites and their corresponding mutational frequencies, sheds light on conserved and structurally restrained regions that can be used for the development of broad-spectrum vaccines and therapeutics.


Subject(s)
Immune Evasion/physiology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/immunology , Binding Sites , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , Cryoelectron Microscopy , Humans , Mutagenesis, Site-Directed , Neutralization Tests , Protein Binding , Protein Domains/immunology , Protein Structure, Quaternary , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Surface Plasmon Resonance , Virus Attachment
9.
SLAS Discov ; 27(1): 8-19, 2022 01.
Article in English | MEDLINE | ID: covidwho-1641663

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 responsible for COVID-19 remains a persistent threat to mankind, especially for the immunocompromised and elderly for which the vaccine may have limited effectiveness. Entry of SARS-CoV-2 requires a high affinity interaction of the viral spike protein with the cellular receptor angiotensin-converting enzyme 2. Novel mutations on the spike protein correlate with the high transmissibility of new variants of SARS-CoV-2, highlighting the need for small molecule inhibitors of virus entry into target cells. We report the identification of such inhibitors through a robust high-throughput screen testing 15,000 small molecules from unique libraries. Several leads were validated in a suite of mechanistic assays, including whole cell SARS-CoV-2 infectivity assays. The main lead compound, calpeptin, was further characterized using SARS-CoV-1 and the novel SARS-CoV-2 variant entry assays, SARS-CoV-2 protease assays and molecular docking. This study reveals calpeptin as a potent and specific inhibitor of SARS-CoV-2 and some variants.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Cysteine Proteinase Inhibitors/pharmacology , Dipeptides/pharmacology , Virus Attachment/drug effects , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2/metabolism , Animals , Cathepsin L/antagonists & inhibitors , Cell Line , Chlorocebus aethiops , Drug Evaluation, Preclinical , Drug Repositioning , HEK293 Cells , Humans , Molecular Docking Simulation , SARS-CoV-2/drug effects , SARS-CoV-2/growth & development , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells
10.
Biomed Res Int ; 2022: 1558860, 2022.
Article in English | MEDLINE | ID: covidwho-1622112

ABSTRACT

Increasing outbreaks of new pathogenic viruses have promoted the exploration of novel alternatives to time-consuming vaccines. Thus, it is necessary to develop a universal approach to halt the spread of new and unknown viruses as they are discovered. One such promising approach is to target lipid membranes, which are common to all viruses and bacteria. The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has reaffirmed the importance of interactions between the virus envelope and the host cell plasma membrane as a critical mechanism of infection. Metadichol®, a nanolipid emulsion of long-chain alcohols, has been demonstrated as a strong candidate that inhibits the proliferation of SARS-CoV-2. Naturally derived substances, such as long-chain saturated lipid alcohols, reduce viral infectivity, including that of coronaviruses (such as SARS-CoV-2) by modifying their lipid-dependent attachment mechanism to human host cells. The receptor ACE2 mediates the entry of SARS-CoV-2 into the host cells, whereas the serine protease TMPRSS2 primes the viral S protein. In this study, Metadichol® was found to be 270 times more potent an inhibitor of TMPRSS2 (EC50 = 96 ng/mL) than camostat mesylate (EC50 = 26000 ng/mL). Additionally, it inhibits ACE with an EC50 of 71 ng/mL, but it is a very weak inhibitor of ACE2 at an EC50 of 31 µg/mL. Furthermore, the live viral assay performed in Caco-2 cells revealed that Metadichol® inhibits SARS-CoV-2 replication at an EC90 of 0.16 µg/mL. Moreover, Metadichol® had an EC90 of 0.00037 µM, making it 2081 and 3371 times more potent than remdesivir (EC50 = 0.77 µM) and chloroquine (EC50 = 1.14 µM), respectively.


Subject(s)
Fatty Alcohols/pharmacology , SARS-CoV-2/drug effects , Viruses/drug effects , Animals , Antiviral Agents/pharmacology , COVID-19/drug therapy , Cell Line , Chlorocebus aethiops , Esters/pharmacology , Guanidines/pharmacology , Humans , Lipid Metabolism/physiology , Lipids/chemistry , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Serine Endopeptidases/drug effects , Serine Endopeptidases/metabolism , Serine Proteases/metabolism , Serine Proteinase Inhibitors/pharmacology , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Attachment/drug effects , Virus Internalization/drug effects
11.
PLoS Biol ; 19(12): e3001510, 2021 12.
Article in English | MEDLINE | ID: covidwho-1592147

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infects a broader range of mammalian species than previously predicted, binding a diversity of angiotensin converting enzyme 2 (ACE2) orthologs despite extensive sequence divergence. Within this sequence degeneracy, we identify a rare sequence combination capable of conferring SARS-CoV-2 resistance. We demonstrate that this sequence was likely unattainable during human evolution due to deleterious effects on ACE2 carboxypeptidase activity, which has vasodilatory and cardioprotective functions in vivo. Across the 25 ACE2 sites implicated in viral binding, we identify 6 amino acid substitutions unique to mouse-one of the only known mammalian species resistant to SARS-CoV-2. Substituting human variants at these positions is sufficient to confer binding of the SARS-CoV-2 S protein to mouse ACE2, facilitating cellular infection. Conversely, substituting mouse variants into either human or dog ACE2 abolishes viral binding, diminishing cellular infection. However, these same substitutions decrease human ACE2 activity by 50% and are predicted as pathogenic, consistent with the extreme rarity of human polymorphisms at these sites. This trade-off can be avoided, however, depending on genetic background; if substituted simultaneously, these same mutations have no deleterious effect on dog ACE2 nor that of the rodent ancestor estimated to exist 70 million years ago. This genetic contingency (epistasis) may have therefore opened the road to resistance for some species, while making humans susceptible to viruses that use these ACE2 surfaces for binding, as does SARS-CoV-2.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Disease Resistance/genetics , Epistasis, Genetic , SARS-CoV-2/physiology , Amino Acids , Angiotensin II/metabolism , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Animals , Binding Sites , COVID-19/enzymology , COVID-19/genetics , Dogs , Evolution, Molecular , Gene Frequency , Humans , Hydrolysis , Mice , Mutation , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Virus Attachment
12.
Viruses ; 13(12)2021 12 16.
Article in English | MEDLINE | ID: covidwho-1576965

ABSTRACT

Porcine epidemic diarrhea virus (PEDV), an enteric coronavirus, causes neonatal pig acute gastrointestinal infection with a characterization of severe diarrhea, vomiting, high morbidity, and high mortality, resulting in tremendous damages to the swine industry. Neither specific antiviral drugs nor effective vaccines are available, posing a high priority to screen antiviral drugs. The aim of this study is to investigate anti-PEDV effects of carbazole alkaloid derivatives. Eighteen carbazole derivatives (No.1 to No.18) were synthesized, and No.5, No.7, and No.18 were identified to markedly reduce the replication of enhanced green fluorescent protein (EGFP) inserted-PEDV, and the mRNA level of PEDV N. Flow cytometry assay, coupled with CCK8 assay, confirmed No.7 and No.18 carbazole derivatives displayed high inhibition effects with low cell toxicity. Furthermore, time course analysis indicated No.7 and No.18 carbazole derivatives exerted inhibition at the early stage of the viral life cycle. Collectively, the analysis underlines the benefit of carbazole derivatives as potential inhibitors of PEDV, and provides candidates for the development of novel therapeutic agents.


Subject(s)
Antiviral Agents/pharmacology , Carbazoles/pharmacology , Porcine epidemic diarrhea virus/drug effects , Animals , Antiviral Agents/chemistry , Carbazoles/chemistry , Cell Survival/drug effects , Chlorocebus aethiops , Dose-Response Relationship, Drug , Molecular Structure , Vero Cells , Virus Attachment/drug effects , Virus Replication/drug effects
13.
Int J Mol Sci ; 22(24)2021 Dec 18.
Article in English | MEDLINE | ID: covidwho-1580690

ABSTRACT

Since the start of the COVID-19 outbreak, pharmaceutical companies and research groups have focused on the development of vaccines and antiviral drugs against SARS-CoV-2. Here, we apply a drug repurposing strategy to identify drug candidates that are able to block the entrance of the virus into human cells. By combining virtual screening with in vitro pseudovirus assays and antiviral assays in Human Lung Tissue (HLT) cells, we identify entrectinib as a potential antiviral drug.


Subject(s)
Benzamides/pharmacology , COVID-19/drug therapy , Indazoles/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/pharmacology , Benzamides/metabolism , COVID-19/metabolism , Cell Line , Chlorocebus aethiops , Drug Evaluation, Preclinical , Drug Repositioning/methods , Humans , Indazoles/metabolism , Lung/pathology , Lung/virology , Molecular Docking Simulation , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Vero Cells , Virus Attachment/drug effects
14.
Viruses ; 13(12)2021 12 06.
Article in English | MEDLINE | ID: covidwho-1555020

ABSTRACT

Porcine deltacoronavirus (PDCoV) is a novel coronavirus that causes diarrhea in nursing piglets. Studies showed that PDCoV uses porcine aminopeptidase N (pAPN) as an entry receptor, but the infection of pAPN-knockout cells or pigs with PDCoV revealed that pAPN might be not a critical functional receptor, implying there exists an unidentified receptor involved in PDCoV infection. Herein, we report that sialic acid (SA) can act as an attachment receptor for PDCoV invasion and facilitate its infection. We first demonstrated that the carbohydrates destroyed on the cell membrane using NaIO4 can alleviate the susceptibility of cells to PDCoV. Further study showed that the removal of SA, a typical cell-surface carbohydrate, could influence the PDCoV infectivity to the cells significantly, suggesting that SA was involved in the infection. The results of plaque assay and Western blotting revealed that SA promoted PDCoV infection by increasing the number of viruses binding to SA on the cell surface during the adsorption phase, which was also confirmed by atomic force microscopy at the microscopic level. In in vivo experiments, we found that the distribution levels of PDCoV and SA were closely relevant in the swine intestine, which contains huge amount of trypsin. We further confirmed that SA-binding capacity to PDCoV is related to the pre-treatment of PDCoV with trypsin. In conclusion, SA is a novel attachment receptor for PDCoV infection to enhance its attachment to cells, which is dependent on the pre-treatment of trypsin on PDCoV. This study paves the way for dissecting the mechanisms of PDCoV-host interactions and provides new strategies to control PDCoV infection.


Subject(s)
Deltacoronavirus/physiology , N-Acetylneuraminic Acid/metabolism , Receptors, Virus/metabolism , Trypsin/metabolism , Virus Attachment , Animals , Carbohydrates , Cell Line , Cell Membrane/metabolism , Cell Membrane/virology , Coronavirus Infections/veterinary , Coronavirus Infections/virology , Deltacoronavirus/drug effects , Host-Pathogen Interactions , Intestines/metabolism , Intestines/virology , Periodic Acid/pharmacology , Swine , Swine Diseases/virology , Trypsin/pharmacology
15.
Nat Methods ; 18(12): 1477-1488, 2021 12.
Article in English | MEDLINE | ID: covidwho-1541247

ABSTRACT

Emergence of new viral agents is driven by evolution of interactions between viral proteins and host targets. For instance, increased infectivity of SARS-CoV-2 compared to SARS-CoV-1 arose in part through rapid evolution along the interface between the spike protein and its human receptor ACE2, leading to increased binding affinity. To facilitate broader exploration of how pathogen-host interactions might impact transmission and virulence in the ongoing COVID-19 pandemic, we performed state-of-the-art interface prediction followed by molecular docking to construct a three-dimensional structural interactome between SARS-CoV-2 and human. We additionally carried out downstream meta-analyses to investigate enrichment of sequence divergence between SARS-CoV-1 and SARS-CoV-2 or human population variants along viral-human protein-interaction interfaces, predict changes in binding affinity by these mutations/variants and further prioritize drug repurposing candidates predicted to competitively bind human targets. We believe this resource ( http://3D-SARS2.yulab.org ) will aid in development and testing of informed hypotheses for SARS-CoV-2 etiology and treatments.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/virology , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Virus Attachment , Biological Evolution , COVID-19/immunology , Genetic Variation , Humans , Models, Molecular , Molecular Structure , Protein Conformation , Spike Glycoprotein, Coronavirus/physiology
16.
Clin Immunol ; 233: 108879, 2021 12.
Article in English | MEDLINE | ID: covidwho-1527619

ABSTRACT

COVID-19 is a pandemic requiring immediate solution for treatment because of its complex pathophysiology. Exploration of novel targets and thus treatment will be life savers which is the need of the hour. 2 host factors- TMPRSS2 and ACE2 are responsible for the way the virus will enter and replicate in the host. Also NRF2 is an important protein responsible for its anti-inflammatory role by multiple mechanisms of action like inhibition of NF-kB, suppression of pro-inflammatory genes, etc. NRF2 is deacetylated by Sirtuins and therefore both have a direct association. Absence of SIRT indicates inhibition of NRF2 expression and thus no anti-oxidative and anti-inflammatory protection for the cell. Therefore, we propose that NRF2 activators and/or SIRT activators can be evaluated to check their efficacy in ameliorating the symptoms of COVID-19.


Subject(s)
COVID-19/immunology , NF-E2-Related Factor 2/immunology , SARS-CoV-2/immunology , Sirtuins/immunology , Angiotensin-Converting Enzyme 2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/metabolism , COVID-19/virology , Host-Pathogen Interactions/immunology , Humans , NF-E2-Related Factor 2/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Serine Endopeptidases/immunology , Serine Endopeptidases/metabolism , Sirtuins/metabolism , Virus Attachment
17.
Viruses ; 13(11)2021 11 19.
Article in English | MEDLINE | ID: covidwho-1524176

ABSTRACT

Anti-viral small molecules are currently lacking for treating coronavirus infection. The long development timescales for such drugs are a major problem, but could be shortened by repurposing existing drugs. We therefore screened a small library of FDA-approved compounds for potential severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antivirals using a pseudovirus system that allows a sensitive read-out of infectivity. A group of structurally-related compounds, showing moderate inhibitory activity with IC50 values in the 2-5 µM range, were identified. Further studies demonstrated that these "kite-shaped" molecules were surprisingly specific for SARS-CoV-1 and SARS-CoV-2 and that they acted early in the entry steps of the viral infectious cycle, but did not affect virus attachment to the cells. Moreover, the compounds were able to prevent infection in both kidney- and lung-derived human cell lines. The structural homology of the hits allowed the production of a well-defined pharmacophore that was found to be highly accurate in predicting the anti-viral activity of the compounds in the screen. We discuss the prospects of repurposing these existing drugs for treating current and future coronavirus outbreaks.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/virology , Leukemia Virus, Murine/drug effects , SARS-CoV-2 , Virus Internalization/drug effects , Animals , Cell Line , Chlorocebus aethiops , Drug Discovery/methods , Drug Repositioning , Drug Synergism , Humans , Leukemia Virus, Murine/metabolism , Mice , Molecular Docking Simulation , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Attachment/drug effects
18.
mBio ; 12(2)2021 03 30.
Article in English | MEDLINE | ID: covidwho-1522913

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently emerged virus that causes coronavirus infectious disease 2019 (COVID-19). SARS-CoV-2 spike protein, like SARS-CoV-1, uses the angiotensin converting enzyme 2 (ACE2) as a cellular receptor to initiate infection. Compounds that interfere with the SARS-CoV-2 spike protein receptor binding domain protein (RBD)-ACE2 receptor interaction may function as entry inhibitors. Here, we used a dual strategy of molecular docking and surface plasmon resonance (SPR) screening of compound libraries to identify those that bind to human ACE2 or the SARS-CoV-2 spike protein receptor binding domain (RBD). Molecular modeling screening interrogated 57,641 compounds and focused on the region of ACE2 that is engaged by RBD of the SARS-CoV-2 spike glycoprotein and vice versa. SPR screening used immobilized human ACE2 and SARS-CoV-2 Spike protein to evaluate the binding of these proteins to a library of 3,141 compounds. These combined screens identified compounds from these libraries that bind at KD (equilibrium dissociation constant) <3 µM affinity to their respective targets, 17 for ACE2 and 6 for SARS-CoV-2 RBD. Twelve ACE2 binders and six of the RBD binders compete with the RBD-ACE2 interaction in an SPR-based competition assay. These compounds included registered drugs and dyes used in biomedical applications. A Vero-E6 cell-based SARS-CoV-2 infection assay was used to evaluate infection blockade by candidate entry inhibitors. Three compounds demonstrated dose-dependent antiviral in vitro potency-Evans blue, sodium lifitegrast, and lumacaftor. This study has identified potential drugs for repurposing as SARS-CoV-2 entry inhibitors or as chemical scaffolds for drug development.IMPORTANCE SARS-CoV-2, the causative agent of COVID-19, has caused more than 60 million cases worldwide with almost 1.5 million deaths as of November 2020. Repurposing existing drugs is the most rapid path to clinical intervention for emerging diseases. Using an in silico screen of 57,641 compounds and a biophysical screen of 3,141 compounds, we identified 22 compounds that bound to either the angiotensin converting enzyme 2 (ACE2) and/or the SARS-CoV-2 spike protein receptor binding domain (SARS-CoV-2 spike protein RBD). Nine of these drugs were identified by both screening methods. Three of the identified compounds, Evans blue, sodium lifitegrast, and lumacaftor, were found to inhibit viral replication in a Vero-E6 cell-based SARS-CoV-2 infection assay and may have utility as repurposed therapeutics. All 22 identified compounds provide scaffolds for the development of new chemical entities for the treatment of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Antiviral Agents/pharmacology , COVID-19/drug therapy , Spike Glycoprotein, Coronavirus/metabolism , Virus Attachment/drug effects , Virus Replication/drug effects , Aminopyridines/pharmacology , Animals , Benzodioxoles/pharmacology , Cell Line , Chlorocebus aethiops , Drug Evaluation, Preclinical , Drug Repositioning , Evans Blue/pharmacology , Humans , Molecular Docking Simulation , Phenylalanine/analogs & derivatives , Phenylalanine/pharmacology , Protein Binding/drug effects , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Sulfones/pharmacology , Surface Plasmon Resonance , Vero Cells
19.
Cell Mol Life Sci ; 78(23): 7777-7794, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1491058

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 requires new treatments both to alleviate the symptoms and to prevent the spread of this disease. Previous studies demonstrated good antiviral and virucidal activity of phospholipase A2s (PLA2s) from snake venoms against viruses from different families but there was no data for coronaviruses. Here we show that PLA2s from snake venoms protect Vero E6 cells against SARS-CoV-2 cytopathic effects. PLA2s showed low cytotoxicity to Vero E6 cells with some activity at micromolar concentrations, but strong antiviral activity at nanomolar concentrations. Dimeric PLA2 from the viper Vipera nikolskii and its subunits manifested especially potent virucidal effects, which were related to their phospholipolytic activity, and inhibited cell-cell fusion mediated by the SARS-CoV-2 spike glycoprotein. Moreover, PLA2s interfered with binding both of an antibody against ACE2 and of the receptor-binding domain of the glycoprotein S to 293T/ACE2 cells. This is the first demonstration of a detrimental effect of PLA2s on ß-coronaviruses. Thus, snake PLA2s are promising for the development of antiviral drugs that target the viral envelope, and could also prove to be useful tools to study the interaction of viruses with host cells.


Subject(s)
Phospholipases A2/pharmacology , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/metabolism , Viper Venoms/pharmacology , Virus Attachment/drug effects , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibody Affinity/drug effects , Antiviral Agents/pharmacology , COVID-19/drug therapy , Cell Fusion , Cell Line , Chlorocebus aethiops , Cytopathogenic Effect, Viral/drug effects , HEK293 Cells , Humans , Models, Molecular , Protein Domains/drug effects , Surface Plasmon Resonance , Vero Cells , Viper Venoms/enzymology
20.
J Virol ; 95(16): e0061721, 2021 07 26.
Article in English | MEDLINE | ID: covidwho-1486509

ABSTRACT

The current pandemic of COVID-19 is caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 spike protein receptor-binding domain (RBD) is the critical determinant of viral tropism and infectivity. To investigate whether naturally occurring RBD mutations during the early transmission phase have altered the receptor binding affinity and infectivity, we first analyzed in silico the binding dynamics between SARS-CoV-2 RBD mutants and the human angiotensin-converting enzyme 2 (ACE2) receptor. Among 32,123 genomes of SARS-CoV-2 isolates (December 2019 through March 2020), 302 nonsynonymous RBD mutants were identified and clustered into 96 mutant types. The six dominant mutations were analyzed applying molecular dynamics simulations (MDS). The mutant type V367F continuously circulating worldwide displayed higher binding affinity to human ACE2 due to the enhanced structural stabilization of the RBD beta-sheet scaffold. The MDS also indicated that it would be difficult for bat SARS-like CoV to infect humans. However, the pangolin CoV is potentially infectious to humans. The increased infectivity of V367 mutants was further validated by performing receptor-ligand binding enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance, and pseudotyped virus assays. Phylogenetic analysis of the genomes of V367F mutants showed that during the early transmission phase, most V367F mutants clustered more closely with the SARS-CoV-2 prototype strain than the dual-mutation variants (V367F+D614G), which may derivate from recombination. The analysis of critical RBD mutations provides further insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin under negative selection pressure and supports the continuing surveillance of spike mutations to aid in the development of new COVID-19 drugs and vaccines. IMPORTANCE A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused the pandemic of COVID-19. The origin of SARS-CoV-2 was associated with zoonotic infections. The spike protein receptor-binding domain (RBD) is identified as the critical determinant of viral tropism and infectivity. Thus, whether mutations in the RBD of the circulating SARS-CoV-2 isolates have altered the receptor binding affinity and made them more infectious has been the research hot spot. Given that SARS-CoV-2 is a novel coronavirus, the significance of our research is in identifying and validating the RBD mutant types emerging during the early transmission phase and increasing human angiotensin-converting enzyme 2 (ACE2) receptor binding affinity and infectivity. Our study provides insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin. The continuing surveillance of RBD mutations with increased human ACE2 affinity in human or other animals is critical to the development of new COVID-19 drugs and vaccines against these variants during the sustained COVID-19 pandemic.


Subject(s)
Amino Acid Substitution , Angiotensin-Converting Enzyme 2/genetics , COVID-19/transmission , Mutation , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Binding Sites , COVID-19/pathology , COVID-19/virology , Gene Expression , Host-Pathogen Interactions/genetics , Humans , Kinetics , Molecular Dynamics Simulation , Phenylalanine/chemistry , Phenylalanine/metabolism , Phylogeny , Protein Binding , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , SARS-CoV-2/classification , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Thermodynamics , Valine/chemistry , Valine/metabolism , Virulence , Virus Attachment
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