scholarly journals Fatty Acid Synthase inhibition prevents palmitoylation of SARS-CoV2 Spike Protein and improves survival of mice infected with murine hepatitis virus

2020 ◽  
Author(s):  
Minhyoung Lee ◽  
Michael Sugiyama ◽  
Katrina Mekhail ◽  
Elyse Latreille ◽  
Negar Khosraviani ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Neutralizing Antibodies ◽  
Fatty Acid Synthase ◽  
Hepatitis Virus ◽  
Spike Protein ◽  
Target Cells ◽  
Murine Hepatitis Virus ◽  
Cell Monolayers ◽  
Decoy Receptors ◽  
Protein Palmitoylation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is the causative agent of COVID19 that has infected >76M people and caused >1.68M deaths. The SARS-CoV2 Spike glycoprotein is responsible for the attachment and infection of target cells. The viral Spike protein serves the basis for many putative therapeutic countermeasures including vaccines, blocking and neutralizing antibodies, and decoy receptors. Here we investigated the cytosolic domain of Spike and its interaction with the protein palmitoyltransferase ZDHHC5. The Spike protein is palmitoylated on multiple juxtamembrane cysteine residues conserved among coronavirus. Increased abundance of ZDHHC5 resulted in hyper-palmitoylation, while silencing of ZDHHC5 reduced the ability of the human CoV 229E to form viral plaques in cell monolayers. Inhibition of fatty acid synthase using the pharmacological inhibitor TVB-3166 eliminated palmitoylation of SARS-CoV2 Spike. Additionally, TVB-3166 attenuated plaque formation and promoted the survival of mice from a lethal murine CoV infection. Thus, inhibition of the Spike protein palmitoylation has the potential to treat SARS-CoV-2 and other CoV infections.

scholarly journals Variations in Disparate Regions of the Murine Coronavirus Spike Protein Impact the Initiation of Membrane Fusion

2001 ◽  
Vol 75 (6) ◽  
pp. 2792-2802 ◽  
Author(s):  
Dawn K. Krueger ◽  
Sean M. Kelly ◽  
Daniel N. Lewicki ◽  
Rosanna Ruffolo ◽  
Thomas M. Gallagher
Keyword(s):  
Tissue Culture ◽  
Membrane Fusion ◽  
Cultured Cells ◽  
Hepatitis Virus ◽  
Fusion Reaction ◽  
Spike Protein ◽  
Soluble Form ◽  
Fusion Activity ◽  
Murine Hepatitis Virus

ABSTRACT The prototype JHM strain of murine hepatitis virus (MHV) is an enveloped, RNA-containing coronavirus that has been selected in vivo for extreme neurovirulence. This virus encodes spike (S) glycoproteins that are extraordinarily effective mediators of intercellular membrane fusion, unique in their ability to initiate fusion even without prior interaction with the primary MHV receptor, a murine carcinoembryonic antigen-related cell adhesion molecule (CEACAM). In considering the possible role of this hyperactive membrane fusion activity in neurovirulence, we discovered that the growth of JHM in tissue culture selected for variants that had lost murine CEACAM-independent fusion activity. Among the collection of variants, mutations were identified in regions encoding both the receptor-binding (S1) and fusion-inducing (S2) subunits of the spike protein. Each mutation was separately introduced into cDNA encoding the prototype JHM spike, and the set of cDNAs was expressed using vaccinia virus vectors. The variant spikes were similar to that of JHM in their assembly into oligomers, their proteolysis into S1 and S2 cleavage products, their transport to cell surfaces, and their affinity for a soluble form of murine CEACAM. However, these tissue culture-adapted spikes were significantly stabilized as S1-S2 heteromers, and their entirely CEACAM-dependent fusion activity was delayed or reduced relative to prototype JHM spikes. The mutations that we have identified therefore point to regions of the S protein that specifically regulate the membrane fusion reaction. We suggest that cultured cells, unlike certain in vivo environments, select for S proteins with delayed, CEACAM-dependent fusion activities that may increase the likelihood of virus internalization prior to the irreversible uncoating process.

scholarly journals Virus-Neutralizing Monoclonal Antibody Expressed in Milk of Transgenic Mice Provides Full Protection against Virus-Induced Encephalitis

2001 ◽  
Vol 75 (6) ◽  
pp. 2803-2809 ◽  
Author(s):  
Andreas F. Kolb ◽  
Lecia Pewe ◽  
John Webster ◽  
Stanley Perlman ◽  
C. Bruce A. Whitelaw ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Neutralizing Antibodies ◽  
Defense Mechanism ◽  
Viral Infections ◽  
Hepatitis Virus ◽  
Recombinant Antibody ◽  
Lethal Dose ◽  
Neutralizing Antibody ◽  
Murine Hepatitis Virus

ABSTRACT Neutralizing antibodies represent a major host defense mechanism against viral infections. In mammals, passive immunity is provided by neutralizing antibodies passed to the offspring via the placenta or the milk as immunoglobulin G and secreted immunoglobulin A. With the long-term goal of producing virus-resistant livestock, we have generated mice carrying transgenes that encode the light and heavy chains of an antibody that is able to neutralize the neurotropic JHM strain of murine hepatitis virus (MHV-JHM). MHV-JHM causes acute encephalitis and acute and chronic demyelination in susceptible strains of mice and rats. Transgene expression was targeted to the lactating mammary gland by using the ovine β-lactoglobulin promoter. Milk from these transgenic mice contained up to 0.7 mg of recombinant antibody/ml. In vitro analysis of milk derived from different transgenic lines revealed a linear correlation between antibody expression and virus-neutralizing activity, indicating that the recombinant antibody is the major determinant of MHV-JHM neutralization in murine milk. Offspring of transgenic and control mice were challenged with a lethal dose of MHV-JHM. Litters suckling nontransgenic dams succumbed to fatal encephalitis, whereas litters suckling transgenic dams were fully protected against challenge, irrespective of whether they were transgenic. This demonstrates that a single neutralizing antibody expressed in the milk of transgenic mice is sufficient to completely protect suckling offspring against MHV-JHM-induced encephalitis.

scholarly journals Optimized Pseudotyping Conditions for the SARS-COV-2 Spike Glycoprotein

2020 ◽  
Vol 94 (21) ◽  
Author(s):  
Marc C. Johnson ◽  
Terri D. Lyddon ◽  
Reinier Suarez ◽  
Braxton Salcedo ◽  
Mary LePique ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Neutralizing Antibodies ◽  
Particle Production ◽  
Surface Glycoprotein ◽  
Spike Protein ◽  
Target Cells ◽  
Spike Glycoprotein ◽  
Infectious Particle ◽  
Pathogenic Virus ◽  
Hiv 1

ABSTRACT The severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) Spike glycoprotein is solely responsible for binding to the host cell receptor and facilitating fusion between the viral and host membranes. The ability to generate viral particles pseudotyped with SARS-COV-2 Spike is useful for many types of studies, such as characterization of neutralizing antibodies or development of fusion-inhibiting small molecules. Here, we characterized the use of a codon-optimized SARS-COV-2 Spike glycoprotein for the generation of pseudotyped HIV-1, murine leukemia virus (MLV), and vesicular stomatitis virus (VSV) particles. The full-length Spike protein functioned inefficiently with all three systems but was enhanced over 10-fold by deleting the last 19 amino acids of the cytoplasmic tail. Infection of 293FT target cells was possible only if the cells were engineered to stably express the human angiotensin-converting enzyme 2 (ACE2) receptor, but stably introducing an additional copy of this receptor did not further enhance susceptibility. Stable introduction of the Spike-activating protease TMPRSS2 further enhanced susceptibility to infection by 5- to 10-fold. Replacement of the signal peptide of the Spike protein with an optimal signal peptide did not enhance or reduce infectious particle production. However, modifications D614G and R682Q further enhanced infectious particle production. With all enhancing elements combined, the titer of pseudotyped HIV-1 particles reached almost 106 infectious particles/ml. Finally, HIV-1 particles pseudotyped with SARS-COV-2 Spike were successfully used to detect neutralizing antibodies in plasma from coronavirus disease 2019 (COVID-19) patients, but not in plasma from uninfected individuals. IMPORTANCE In work with pathogenic viruses, it is useful to have rapid quantitative tests for viral infectivity that can be performed without strict biocontainment restrictions. A common way of accomplishing this is to generate viral pseudoparticles that contain the surface glycoprotein from the pathogenic virus incorporated into a replication-defective viral particle that contains a sensitive reporter system. These pseudoparticles enter cells using the glycoprotein from the pathogenic virus, leading to a readout for infection. Conditions that block entry of the pathogenic virus, such as neutralizing antibodies, will also block entry of the viral pseudoparticles. However, viral glycoproteins often are not readily suited for generating pseudoparticles. Here, we describe a series of modifications that result in the production of relatively high-titer SARS-COV-2 pseudoparticles that are suitable for the detection of neutralizing antibodies from COVID-19 patients.

scholarly journals In silico screening of JAK-STAT modulators from the antiviral plants of Indian traditional system of medicine with the potential to inhibit 2019 novel coronavirus

2020 ◽  
Author(s):  
Pukar Khanal ◽  
Taaza Duyu ◽  
BM Patil ◽  
Yadu Nandan Dey ◽  
Ismail Pasha ◽  
...  
Keyword(s):  
Immune System ◽  
Hepatitis Virus ◽  
Docking Study ◽  
Spike Protein ◽  
Murine Hepatitis Virus ◽  
Traditional System ◽  
Diarrhea Virus ◽  
Associated Proteins ◽  
Novel Coronavirus ◽  
Stat Pathway

Abstract Aim. The present study was aimed to identify the lead hits from reported anti-viral Indian medicinal plants to modulate the proteins through the JAK-STAT pathway and to identify the proteins that share the domain with coronavirus (COVID19) associated proteins i.e. 3CLpro, PLpro, and spike protein. Methods. The reported anti-viral plants were screened from the available databases and published literature; their phytoconstituents were retrieved, gene-expression was predicted and the modulated proteins in JAK-STAT pathway were predicted. The interaction between proteins was evaluated using STRING and the network between phytoconstituents and proteins was constructed using Cytoscape. The druglikeness score was predicted using MolSoft and the ADMET profile of phytoconstituents was evaluated using admetSAR2.0. The domain of three proteins i.e. 3CLpro, PLpro, and spike protein of coronavirus was compared using NCBI blastP against the RCSB database. Results. The majority of the phytoconstituents from the anti-viral plants were predicted to target TRAF5 protein in the JAK-STAT pathway; among them, vitexilactone was predicted to possess the highest druglikeness score. Proteins targeted in the JAK-STAT pathways were also predicted to modulate the immune system. Similarly, the docking study identified sesaminol 2-O-β-D-gentiobioside to possess the highest binding affinity with spike protein. Similarly, phylogeny comparison also identified the common protein domains with other stains of microbes like murine hepatitis virus strain A59, avian infectious bronchitis virus, and porcine epidemic diarrhea virus CV777. Conclusion. Although, the present study is based on computer simulations and database mining, it provides two important aspects in identifying the lead hits against coronavirus. First, targeting the JAK-STAT pathway in the corona-infected host by folk anti-viral agents can regulate the immune system which would inhibit spreading the virus inside the subject. Secondly, the well-known targets of coronavirus i.e. 3CLpro, PLpro, and spike protein share some common domains with other proteins of different microbial strains.

scholarly journals Development of a novel hybrid alphavirus-SARS-CoV-2 particle for rapid in vitro screening and quantification of neutralization antibodies, antiviral drugs, and viral mutations

2020 ◽  
Author(s):  
Brian Hetrick ◽  
Sijia He ◽  
Linda D. Chilin ◽  
Deemah Dabbagh ◽  
Farhang Alem ◽  
...  
Keyword(s):  
Viral Entry ◽  
Neutralizing Antibodies ◽  
Protein S ◽  
Antiviral Drugs ◽  
Spike Protein ◽  
Structural Proteins ◽  
Rapid Screening ◽  
Target Cells ◽  
Rapid Monitoring

SUMMARYTimely development of vaccines and antiviral drugs are critical to control the coronavirus disease 2019 (COVID-19) global pandemic 1–6. Current methods for validation of vaccine efficacy involve the use of pseudoviruses, such as the SARS-CoV-2 spike protein (S) pseudotyped lentivirus or vesicular stomatitis virus (VSV), to quantify neutralizing antibodies for blocking viral infection 7–14. The process of pseudovirus infection and quantification is time consuming and can take days to complete. In addition, pseudoviruses contain structural proteins not native to SARS-CoV-2, which may alter particle properties in receptor binding and responses to antibody neutralization 15. Here we describe the development of a new hybrid alphavirus-SARS-CoV-2 particle (Ha-CoV-2) for rapid screening and quantification of neutralization antibodies and antiviral drugs. Ha-CoV-2 is a non-replicating SARS-CoV-2 virus-like particle, composed of only SARS-CoV-2 structural proteins (S, M, N, and E) and a RNA genome derived from a fast expressing alphavirus vector 16. We demonstrate that Ha-CoV-2 can rapidly and robustly express reporter genes in target cells within 3-5 hours following viral entry. We further validate the Ha-CoV-2 system for rapid quantification of neutralization antibodies and antiviral drugs. In addition, we assembled a Ha-CoV-2 particle bearing the D614G mutant spike protein, and found that the mutation led to an approximately 200% increase in virion infectivity. These results demonstrate that Ha-CoV-2 can also be applied for rapid monitoring and quantification of viral mutations for effects on neutralizing antibodies induced by vaccines.

The Viral Spike Protein Is Not Involved in the Polarized Sorting of Coronaviruses in Epithelial Cells

1998 ◽  
Vol 72 (1) ◽  
pp. 497-503 ◽  
Author(s):  
J. W. A. Rossen ◽  
R. de Beer ◽  
G.-J. Godeke ◽  
M. J. B. Raamsman ◽  
M. C. Horzinek ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Secretory Pathway ◽  
Hepatitis Virus ◽  
Spike Protein ◽  
Transmissible Gastroenteritis Virus ◽  
Secretory Proteins ◽  
Temperature Sensitive ◽  
Murine Hepatitis Virus ◽  
Basolateral Membranes ◽  
Transmissible Gastroenteritis

ABSTRACT Coronaviruses are assembled by budding into a pre-Golgi compartment from which they are transported along the secretory pathway to leave the cell. In cultured epithelial cells, they are released in a polarized fashion; depending on the virus and cell type, they are sorted preferentially either to the apical domain or to the basolateral plasma membrane domain. In this study, we investigated the role of the coronavirus spike protein, because of its prominent position in the virion the prime sorting candidate, in the directionality of virus release. Three independent approaches were taken. (i) The inhibition of N glycosylation by tunicamycin resulted in the synthesis of spikeless virions. The absence of spikes, however, did not influence the polarity in the release of virions. Thus, murine hepatitis virus strain A59 (MHV-A59) was still secreted from the basolateral membranes of mTAL and LMR cells and from the apical sides of MDCKMHVRcells, whereas transmissible gastroenteritis virus (TGEV) was still released from the apical surfaces of LMR cells. (ii) Spikeless virions were also studied by using the MHV-A59 temperature-sensitive mutant Albany 18. When these virions were produced in infected LMR and MDCKMHVR cells at the nonpermissive temperature, they were again preferentially released from basolateral and apical membranes, respectively. (iii) We recently demonstrated that coronavirus-like particles resembling normal virions were assembled and released when the envelope proteins M and E were coexpressed in cells (H. Vennema, G.-J. Godeke, J. W. A. Rossen, W. F. Voorhout, M. C. Horzinek, D.-J. E. Opstelten, and P. J. M. Rottier, EMBO J. 15:2020–2028, 1996). The spikeless particles produced in mTAL cells by using recombinant Semliki Forest viruses to express these two genes of MHV-A59 were specifically released from basolateral membranes, i.e., with the same polarity as that of wild-type MHV-A59. Our results thus consistently demonstrate that the spike protein is not involved in the directional sorting of coronaviruses in epithelial cells. In addition, our observations with tunicamycin show that contrary to the results with some secretory proteins, the N-linked oligosaccharides present on the viral M proteins of coronaviruses such as TGEV also play no role in viral sorting. The implications of these conclusions are discussed.

scholarly journals Coronaviruses Induce Entry-Independent, Continuous Macropinocytosis

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Megan Culler Freeman ◽  
Christopher T. Peek ◽  
Michelle M. Becker ◽  
Everett Clinton Smith ◽  
Mark R. Denison
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Severe Acute Respiratory Syndrome ◽  
Hepatitis Virus ◽  
Growth Factor Receptor ◽  
Spike Protein ◽  
Human Pathogens ◽  
Murine Hepatitis Virus ◽  
Epidermal Growth

ABSTRACTMacropinocytosis is exploited by many pathogens for entry into cells. Coronaviruses (CoVs) such as severe acute respiratory syndrome (SARS) CoV and Middle East respiratory syndrome CoV are important human pathogens; however, macropinocytosis during CoV infection has not been investigated. We demonstrate that the CoVs SARS CoV and murine hepatitis virus (MHV) induce macropinocytosis, which occurs late during infection, is continuous, and is not associated with virus entry. MHV-induced macropinocytosis results in vesicle internalization, as well as extended filopodia capable of fusing with distant cells. MHV-induced macropinocytosis requires fusogenic spike protein on the cell surface and is dependent on epidermal growth factor receptor activation. Inhibition of macropinocytosis reduces supernatant viral titers and syncytia but not intracellular virus titers. These results indicate that macropinocytosis likely facilitates CoV infection through enhanced cell-to-cell spreading. Our studies are the first to demonstrate virus use of macropinocytosis for a role other than entry and suggest a much broader potential exploitation of macropinocytosis in virus replication and host interactions.IMPORTANCECoronaviruses (CoVs), including severe acute respiratory syndrome (SARS) CoV and Middle East respiratory syndrome CoV, are critical emerging human pathogens. Macropinocytosis is induced by many pathogens to enter host cells, but other functions for macropinocytosis in virus replication are unknown. In this work, we show that CoVs induce a macropinocytosis late in infection that is continuous, independent from cell entry, and associated with increased virus titers and cell fusion. Murine hepatitis virus macropinocytosis requires a fusogenic virus spike protein and signals through the epidermal growth factor receptor and the classical macropinocytosis pathway. These studies demonstrate CoV induction of macropinocytosis for a purpose other than entry and indicate that viruses likely exploit macropinocytosis at multiple steps in replication and pathogenesis.

scholarly journals Optimized pseudotyping conditions for the SARS-COV2 Spike glycoprotein

2020 ◽  
Author(s):  
Marc C. Johnson ◽  
Terri D. Lyddon ◽  
Reinier Suarez ◽  
Braxton Salcedo ◽  
Mary LePique ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Neutralizing Antibodies ◽  
Particle Production ◽  
Spike Protein ◽  
Single Amino Acid ◽  
Target Cells ◽  
Spike Glycoprotein ◽  
Infectious Particle ◽  
Pathogenic Virus ◽  
Hiv 1

AbstractThe SARS-COV2 Spike glycoprotein is solely responsible for binding to the host cell receptor and facilitating fusion between the viral and host membranes. The ability to generate viral particles pseudotyped with SARS-COV2 Spike is useful for many types of studies, such as characterization of neutralizing antibodies or development of fusion-inhibiting small molecules. Here we characterized the use of a codon-optimized SARS-COV2 Spike glycoprotein for the generation of pseudotyped HIV-1, MLV, and VSV particles. The full-length Spike protein functioned inefficiently with all three systems but was enhanced over 10-fold by deleting the last 19 amino acids of the cytoplasmic tail of Spike. Infection of 293FT target cells was only possible if the cells were engineered to stably express the human ACE-2 receptor, but stably introducing an additional copy of this receptor did not further enhance susceptibility. Stable introduction of the Spike activating protease TMPRSS2 further enhanced susceptibility to infection by 5-10 fold. Substitution of the signal peptide of the Spike protein with an optimal signal peptide did not enhance or reduce infectious particle production. However, modification of a single amino acid in the furin cleavage site of Spike (R682Q) enhanced infectious particle production another 10-fold. With all enhancing elements combined, the titer of pseudotyped particles reached almost 106 infectious particles/ml. Finally, HIV-1 particles pseudotyped with SARS-COV2 Spike was successfully used to detect neutralizing antibodies in plasma from COVID-19 patients, but not plasma from uninfected individuals.ImportanceWhen working with pathogenic viruses, it is useful to have rapid quantitative tests for viral infectivity that can be performed without strict biocontainment restrictions. A common way of accomplishing this is to generate viral pseudoparticles that contain the surface glycoprotein from the pathogenic virus incorporated into a replication-defective viral particle that contains a sensitive reporter system. These pseudoparticles enter cells using the glycoprotein from the pathogenic virus leading to a readout for infection. Conditions that block entry of the pathogenic virus, such as neutralizing antibodies, will also block entry of the viral pseudoparticles. However, viral glycoproteins often are not readily suited for generating pseudoparticles. Here we describe a series of modifications that result in the production of relatively high titer SARS-COV2 pseudoparticles that are suitable for detection of neutralizing antibodies from COVID-19 patients.

scholarly journals Membrane fusion and immune evasion by the spike protein of SARS-CoV-2 Delta variant

2021 ◽  
Author(s):  
Jun Zhang ◽  
Tianshu Xiao ◽  
Yongfei Cai ◽  
Christy L. Lavine ◽  
Hanqin Peng ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Immune Evasion ◽  
Neutralizing Antibodies ◽  
Intervention Strategies ◽  
Spike Protein ◽  
Target Cells ◽  
Cellular Receptor ◽  
Receptor Binding Domain ◽  
Low Levels ◽  
Guide Intervention

AbstractThe Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has outcompeted previously prevalent variants and become a dominant strain worldwide. We report here structure, function and antigenicity of its full-length spike (S) trimer in comparison with those of other variants, including Gamma, Kappa, and previously characterized Alpha and Beta. Delta S can fuse membranes more efficiently at low levels of cellular receptor ACE2 and its pseudotyped viruses infect target cells substantially faster than all other variants tested, possibly accounting for its heightened transmissibility. Mutations of each variant rearrange the antigenic surface of the N-terminal domain of the S protein in a unique way, but only cause local changes in the receptor-binding domain, consistent with greater resistance particular to neutralizing antibodies. These results advance our molecular understanding of distinct properties of these viruses and may guide intervention strategies.

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