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1.
Viruses ; 14(5)2022 05 02.
Article in English | MEDLINE | ID: covidwho-1820417

ABSTRACT

The emergence of new SARS-CoV-2 variants and the replacement of preceding isolates have been observed through B.1.1.7, B.1.351, B.1.617.2, and B.1.1.529 lineages (corresponding to alpha, beta, delta, and omicron variants of concern (VoC), respectively). However, there is still a lack of biological evidence to which extent those VoC differ from the ancestral lineages. By exploiting human airway epithelial cell (HAEC) cultures, which closely resemble the human airway architecture and physiology, we report distinctive SARS-CoV-2 tropism in different respiratory tissues. In general, SARS-CoV-2 VoC predominantly infect and replicate in HAEC better than the progenitor USA-WA1 isolate or the BavPat1 isolate, which contains the D614G mutation, even though there is little to no difference between variants regarding their infectivity (i.e., virion-per-vRNA copy ratio). We also observe differential tissue-specific innate immunity activation between the upper and lower respiratory tissues in the presence of the virus. Our study provides better comprehension of the behavior of the different VoC in this physiologically relevant ex vivo model.


Subject(s)
COVID-19 , Cytokines , Epithelial Cells , SARS-CoV-2 , COVID-19/immunology , COVID-19/virology , Cytokines/metabolism , Epithelial Cells/virology , Humans , SARS-CoV-2/pathogenicity , Virion/pathogenicity
2.
Life Sci ; 295: 120411, 2022 Apr 15.
Article in English | MEDLINE | ID: covidwho-1683412

ABSTRACT

AIMS: Virus-infected host cells switch their metabolism to a more glycolytic phenotype, required for new virion synthesis and packaging. Therefore, we investigated the effect and mechanistic action of glycolytic inhibitor 2-Deoxy-d-glucose (2-DG) on virus multiplication in host cells following SARS-CoV-2 infection. MAIN METHODS: SARS-CoV-2 induced change in glycolysis was examined in Vero E6 cells. Effect of 2-DG on virus multiplication was evaluated by RT-PCR (N and RdRp genes) analysis, protein expression analysis of Nucleocapsid (N) and Spike (S) proteins and visual indication of cytopathy effect (CPE), The mass spectrometry analysis was performed to examine the 2-DG induced change in glycosylation status of receptor binding domain (RBD) in SARS-CoV-2 spike protein. KEY FINDINGS: We observed SARS-COV-2 infection induced increased glucose influx and glycolysis, resulting in selectively high accumulation of the fluorescent glucose analog, 2-NBDG in Vero E6 cells. 2-DG inhibited glycolysis, reduced virus multiplication and alleviated cells from virus-induced cytopathic effect (CPE) in SARS-CoV-2 infected cells. The progeny virions produced from 2-DG treated cells were found unglycosylated at crucial N-glycosites (N331 and N343) of the receptor-binding domain (RBD) in the spike protein, resulting in production of defective progeny virions with compromised infective potential. SIGNIFICANCE: The mechanistic study revealed that the inhibition of SARS-COV-2 multiplication is attributed to 2-DG induced glycolysis inhibition and possibly un-glycosylation of the spike protein, also. Therefore, based on its previous human trials in different types of Cancer and Herpes patients, it could be a potential molecule to study in COVID-19 patients.


Subject(s)
COVID-19/drug therapy , Deoxyglucose/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity , Adenosine Triphosphate/metabolism , Animals , Antiviral Agents/pharmacology , COVID-19/metabolism , COVID-19/virology , Cell Proliferation/drug effects , Cell Survival/drug effects , Chlorocebus aethiops , Glucose/metabolism , Glycolysis/drug effects , Glycosylation , Host-Pathogen Interactions/drug effects , Mannose/pharmacology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virion/drug effects , Virion/pathogenicity , Virus Replication/drug effects
3.
J Cell Mol Med ; 26(1): 25-34, 2022 01.
Article in English | MEDLINE | ID: covidwho-1570773

ABSTRACT

Transmission electron microscopy has historically been indispensable for virology research, as it offers unique insight into virus function. In the past decade, as cryo-electron microscopy (cryo-EM) has matured and become more accessible, we have been able to peer into the structure of viruses at the atomic level and understand how they interact with the host cell, with drugs or with antibodies. Perhaps, there was no time in recent history where cryo-EM was more needed, as SARS-CoV-2 has spread around the globe, causing millions of deaths and almost unquantifiable economic devastation. In this concise review, we aim to mark the most important contributions of cryo-EM to understanding the structure and function of SARS-CoV-2 proteins, from surface spikes to the virus core and from virus-receptor interactions to antibody binding.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Antibodies, Viral/chemistry , COVID-19 Vaccines/chemistry , COVID-19/prevention & control , Receptors, Virus/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Angiotensin-Converting Enzyme 2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/biosynthesis , COVID-19/immunology , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/biosynthesis , Cryoelectron Microscopy , Epitopes/chemistry , Epitopes/immunology , Epitopes/metabolism , Humans , Models, Molecular , Protein Binding , Protein Interaction Domains and Motifs , Protein Structure, Secondary , Receptors, Virus/immunology , Receptors, Virus/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity , SARS-CoV-2/ultrastructure , Serine Endopeptidases/chemistry , Serine Endopeptidases/immunology , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Virion/drug effects , Virion/pathogenicity , Virion/ultrastructure
4.
Cell Host Microbe ; 29(12): 1788-1801.e6, 2021 12 08.
Article in English | MEDLINE | ID: covidwho-1509671

ABSTRACT

Previous work found that the co-occurring mutations R203K/G204R on the SARS-CoV-2 nucleocapsid (N) protein are increasing in frequency among emerging variants of concern or interest. Through a combination of in silico analyses, this study demonstrates that R203K/G204R are adaptive, while large-scale phylogenetic analyses indicate that R203K/G204R associate with the emergence of the high-transmissibility SARS-CoV-2 lineage B.1.1.7. Competition experiments suggest that the 203K/204R variants possess a replication advantage over the preceding R203/G204 variants, possibly related to ribonucleocapsid (RNP) assembly. Moreover, the 203K/204R virus shows increased infectivity in human lung cells and hamsters. Accordingly, we observe a positive association between increased COVID-19 severity and sample frequency of 203K/204R. Our work suggests that the 203K/204R mutations contribute to the increased transmission and virulence of select SARS-CoV-2 variants. In addition to mutations in the spike protein, mutations in the nucleocapsid protein are important for viral spreading during the pandemic.


Subject(s)
Amino Acid Substitution , COVID-19/pathology , Coronavirus Nucleocapsid Proteins/genetics , Genome, Viral , Mutation , SARS-CoV-2/genetics , Animals , COVID-19/epidemiology , COVID-19/virology , Cell Line , Coronavirus Nucleocapsid Proteins/chemistry , Coronavirus Nucleocapsid Proteins/metabolism , Cricetulus , Epithelial Cells/pathology , Epithelial Cells/virology , Gene Expression , Genetic Fitness , Humans , Models, Molecular , Mutagenesis , Phosphoproteins/chemistry , Phosphoproteins/genetics , Phosphoproteins/metabolism , Phylogeny , Protein Conformation , SARS-CoV-2/classification , SARS-CoV-2/growth & development , SARS-CoV-2/pathogenicity , Selection, Genetic , Severity of Illness Index , Virion/genetics , Virion/growth & development , Virion/pathogenicity , Virulence , Virus Replication
5.
Bioessays ; 43(6): e2000312, 2021 06.
Article in English | MEDLINE | ID: covidwho-1184571

ABSTRACT

Biocidal agents such as formaldehyde and glutaraldehyde are able to inactivate several coronaviruses including SARS-CoV-2. In this article, an insight into one mechanism for the inactivation of these viruses by those two agents is presented, based on analysis of previous observations during electron microscopic examination of several members of the orthocoronavirinae subfamily, including the new virus SARS-CoV-2. This inactivation is proposed to occur through Schiff base reaction-induced conformational changes in the spike glycoprotein leading to its disruption or breakage, which can prevent binding of the virus to cellular receptors. Also, a new prophylactic and therapeutic measure against SARS-CoV-2 using acetoacetate is proposed, suggesting that it could similarly break the viral spike through Schiff base reaction with lysines of the spike protein. This measure needs to be confirmed experimentally before consideration. In addition, a new line of research is proposed to help find a broad-spectrum antivirus against several members of this subfamily.


Subject(s)
Disinfectants/pharmacology , Ketone Bodies/pharmacology , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/metabolism , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Disinfectants/chemistry , Formaldehyde/chemistry , Formaldehyde/pharmacology , Glutaral/chemistry , Glutaral/pharmacology , Humans , Ketone Bodies/chemistry , Ketone Bodies/metabolism , Ketosis/etiology , Ketosis/virology , SARS-CoV-2/pathogenicity , Virion/drug effects , Virion/pathogenicity
6.
Cardiovasc Res ; 117(6): 1557-1566, 2021 05 25.
Article in English | MEDLINE | ID: covidwho-1127334

ABSTRACT

AIMS: Patients with severe respiratory syndrome caused by SARS-CoV-2 undergo cardiac complications due to hyper-inflammatory conditions. Although the presence of the virus has been detected in the myocardium of infected patients, and infection of induced pluripotent cell-derived cardiomyocytes has been demonstrated, the reported expression of Angiotensin-Converting Enzyme-2 (ACE2) in cardiac stromal cells suggests that SARS-CoV-2 may determine cardiac injury by sustaining productive infection and increasing inflammation. METHODS AND RESULTS: We analysed expression of ACE2 receptor in primary human cardiac stromal cells derived from cardiospheres, using proteomics and transcriptomics before exposing them to SARS-CoV-2 in vitro. Using conventional and high sensitivity PCR methods, we measured virus release in the cellular supernatants and monitored the intracellular viral bioprocessing. We performed high-resolution imaging to show the sites of intracellular viral production and demonstrated the presence of viral particles in the cells with electron microscopy. We finally used RT-qPCR assays to detect genes linked to innate immunity and fibrotic pathways coherently regulated in cells after exposure to the virus. CONCLUSIONS: Our findings indicate that cardiac stromal cells are susceptible to SARS-CoV-2 infection and produce variable viral yields depending on the extent of cellular ACE2 receptor expression. Interestingly, these cells also evolved towards hyper-inflammatory/pro-fibrotic phenotypes independently of ACE2 levels. Thus, SARS-CoV-2 infection of myocardial stromal cells could be involved in cardiac injury and explain the high number of complications observed in severe cases of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/virology , Heart Diseases/virology , Myocardium/enzymology , Receptors, Virus/metabolism , SARS-CoV-2/pathogenicity , Stromal Cells/virology , Virion/pathogenicity , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/genetics , Animals , COVID-19/complications , Chlorocebus aethiops , Female , Fibrosis , Heart Diseases/enzymology , Heart Diseases/pathology , Host-Pathogen Interactions , Humans , Inflammation Mediators/metabolism , Male , Middle Aged , Myocardium/ultrastructure , Phenotype , Receptors, Virus/genetics , SARS-CoV-2/ultrastructure , Spheroids, Cellular , Stromal Cells/enzymology , Stromal Cells/ultrastructure , Vero Cells , Virion/ultrastructure
7.
Adv Colloid Interface Sci ; 290: 102400, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1116130

ABSTRACT

We review concepts involved in describing the chemodynamic features of nanoparticles and apply the framework to gain physicochemical insights into interactions between SARS-CoV-2 virions and airborne particulate matter (PM). Our analysis is highly pertinent given that the World Health Organisation acknowledges that SARS-CoV-2 may be transmitted by respiratory droplets, and the US Center for Disease Control and Prevention recognises that airborne transmission of SARS-CoV-2 can occur. In our theoretical treatment, the virion is assimilated to a core-shell nanoparticle, and contributions of various interaction energies to the virion-PM association (electrostatic, hydrophobic, London-van der Waals, etc.) are generically included. We review the limited available literature on the physicochemical features of the SARS-CoV-2 virion and identify knowledge gaps. Despite the lack of quantitative data, our conceptual framework qualitatively predicts that virion-PM entities are largely able to maintain equilibrium on the timescale of their diffusion towards the host cell surface. Comparison of the relevant mass transport coefficients reveals that virion biointernalization demand by alveolar host cells may be greater than the diffusive supply. Under such conditions both the free and PM-sorbed virions may contribute to the transmitted dose. This result points to the potential for PM to serve as a shuttle for delivery of virions to host cell targets. Thus, our critical review reveals that the chemodynamics of virion-PM interactions may play a crucial role in the transmission of COVID-19, and provides a sound basis for explaining reported correlations between episodes of air pollution and outbreaks of COVID-19.


Subject(s)
COVID-19/transmission , Epithelial Cells/virology , Particulate Matter/chemistry , SARS-CoV-2/chemistry , Virion/chemistry , Aerosols , Biomechanical Phenomena , COVID-19/virology , Diffusion , Humans , Hydrophobic and Hydrophilic Interactions , Models, Chemical , Nanoparticles/chemistry , Pulmonary Alveoli/virology , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Static Electricity , Virion/metabolism , Virion/pathogenicity , Virus Internalization , Water/chemistry
8.
Nature ; 592(7852): 116-121, 2021 04.
Article in English | MEDLINE | ID: covidwho-892040

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein substitution D614G became dominant during the coronavirus disease 2019 (COVID-19) pandemic1,2. However, the effect of this variant on viral spread and vaccine efficacy remains to be defined. Here we engineered the spike D614G substitution in the USA-WA1/2020 SARS-CoV-2 strain, and found that it enhances viral replication in human lung epithelial cells and primary human airway tissues by increasing the infectivity and stability of virions. Hamsters infected with SARS-CoV-2 expressing spike(D614G) (G614 virus) produced higher infectious titres in nasal washes and the trachea, but not in the lungs, supporting clinical evidence showing that the mutation enhances viral loads in the upper respiratory tract of COVID-19 patients and may increase transmission. Sera from hamsters infected with D614 virus exhibit modestly higher neutralization titres against G614 virus than against D614 virus, suggesting that the mutation is unlikely to reduce the ability of vaccines in clinical trials to protect against COVID-19, and that therapeutic antibodies should be tested against the circulating G614 virus. Together with clinical findings, our work underscores the importance of this variant in viral spread and its implications for vaccine efficacy and antibody therapy.


Subject(s)
COVID-19/transmission , COVID-19/virology , Genetic Fitness , Mutation , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/genetics , Animals , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , COVID-19/immunology , COVID-19 Vaccines/immunology , Cricetinae , Disease Models, Animal , Humans , Lung/virology , Male , Mesocricetus/virology , Models, Biological , Nasal Mucosa/virology , Neutralization Tests , Protein Stability , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Tissue Culture Techniques , Trachea/virology , Viral Load , Virion/chemistry , Virion/pathogenicity , Virion/physiology , Virus Replication/genetics
9.
J Med Virol ; 92(10): 2087-2095, 2020 10.
Article in English | MEDLINE | ID: covidwho-763177

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) is the causative agent of the coronavirus disease-2019 (COVID-19) pandemic. Coronaviruses enter cells via fusion of the viral envelope with the plasma membrane and/or via fusion of the viral envelope with endosomal membranes after virion endocytosis. The spike (S) glycoprotein is a major determinant of virus infectivity. Herein, we show that the transient expression of the SARS CoV-2 S glycoprotein in Vero cells caused extensive cell fusion (formation of syncytia) in comparison to limited cell fusion caused by the SARS S glycoprotein. Both S glycoproteins were detected intracellularly and on transfected Vero cell surfaces. These results are in agreement with published pathology observations of extensive syncytia formation in lung tissues of patients with COVID-19. These results suggest that SARS CoV-2 is able to spread from cell-to-cell much more efficiently than SARS effectively avoiding extracellular neutralizing antibodies. A systematic screening of several drugs including cardiac glycosides and kinase inhibitors and inhibitors of human immunodeficiency virus (HIV) entry revealed that only the FDA-approved HIV protease inhibitor, nelfinavir mesylate (Viracept) drastically inhibited S-n- and S-o-mediated cell fusion with complete inhibition at a 10-µM concentration. In-silico docking experiments suggested the possibility that nelfinavir may bind inside the S trimer structure, proximal to the S2 amino terminus directly inhibiting S-n- and S-o-mediated membrane fusion. Also, it is possible that nelfinavir may act to inhibit S proteolytic processing within cells. These results warrant further investigations of the potential of nelfinavir mesylate to inhibit virus spread at early times after SARS CoV-2 symptoms appear.


Subject(s)
Anti-HIV Agents/pharmacology , Membrane Fusion/drug effects , Nelfinavir/pharmacology , SARS Virus/drug effects , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Animals , Anti-HIV Agents/chemistry , Binding Sites , COVID-19/drug therapy , Cell Fusion , Chlorocebus aethiops , Giant Cells/drug effects , Giant Cells/pathology , Giant Cells/virology , Humans , Molecular Docking Simulation , Nelfinavir/chemistry , Plasmids/chemistry , Plasmids/metabolism , Protein Binding , Protein Interaction Domains and Motifs , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , SARS Virus/pathogenicity , SARS Virus/physiology , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virion/drug effects , Virion/pathogenicity , Virion/physiology
11.
Adv Biosyst ; 4(7): e2000105, 2020 07.
Article in English | MEDLINE | ID: covidwho-361328

ABSTRACT

With the emergence of COVID-19, it is important to address the possible scenarios of SARS-CoV-2 virulence. Although several researchers have addressed the possible mechanisms of enveloped virus transfection, for example, influenza, here, the relationship between exhaled virus laden-particles, the climate, and transfection probability is discussed by interpreting the findings of prior studies. Importantly, the higher probability of viral transfection in cold and dry public spaces such as near cold shelves of groceries is illustrated. Thus, additional protective measures in such spaces are recommended.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Virion/pathogenicity , Betacoronavirus/physiology , COVID-19 , Climate , Coronavirus Infections/prevention & control , Humans , Pandemics/prevention & control , Personal Protective Equipment/supply & distribution , Physical Distancing , Pneumonia, Viral/prevention & control , SARS-CoV-2 , Temperature , Virion/physiology , Virulence
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