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1.
Cell Rep ; 39(11): 110954, 2022 Jun 14.
Article in English | MEDLINE | ID: covidwho-1866958

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to shutoff of protein synthesis, and nsp1, a central shutoff factor in coronaviruses, inhibits cellular mRNA translation. However, the diverse molecular mechanisms employed by nsp1 as well as its functional importance are unresolved. By overexpressing various nsp1 mutants and generating a SARS-CoV-2 mutant, we show that nsp1, through inhibition of translation and induction of mRNA degradation, targets translated cellular mRNA and is the main driver of host shutoff during infection. The propagation of nsp1 mutant virus is inhibited exclusively in cells with intact interferon (IFN) pathway as well as in vivo, in hamsters, and this attenuation is associated with stronger induction of type I IFN response. Therefore, although nsp1's shutoff activity is broad, it plays an essential role, specifically in counteracting the IFN response. Overall, our results reveal the multifaceted approach nsp1 uses to shut off cellular protein synthesis and uncover nsp1's explicit role in blocking the IFN response.


Subject(s)
COVID-19 , Viral Nonstructural Proteins , Cell Line , Humans , RNA Stability , SARS-CoV-2 , Viral Nonstructural Proteins/metabolism
2.
Arch Toxicol ; 2022 May 17.
Article in English | MEDLINE | ID: covidwho-1844344

ABSTRACT

BriLife®, a vector-based vaccine that utilizes the recombinant vesicular stomatitis virus (VSV) platform to express and present the spike antigen of SARS-CoV-2, is undergoing testing in a phase 2 clinical trial in Israel. A nonclinical repeated-dose (GLP) toxicity study in New Zealand white rabbits was performed to evaluate the potential toxicity, local tolerance, immunogenicity and biodistribution of the vaccine. rVSV-ΔG-SARS-CoV-2-S (or vehicle) was administered intramuscularly to two groups of animals (106, 107 PFU/animal, n = 10/sex/group) on three occasions, at 2-week intervals, followed by a 3-week recovery period. Systemic clinical signs, local reactions, body weight, body temperature, food consumption, ophthalmology, urinalysis, clinical pathology, C-reactive protein, viremia and antibody levels were monitored. Gross pathology was performed, followed by organs/tissues collection for biodistribution and histopathological evaluation. Treatment-related changes were restricted to multifocal minimal myofiber necrosis at the injection sites, and increased lymphocytic cellularity in the iliac and mesenteric lymph nodes and in the spleen. These changes were considered related to the inflammatory reaction elicited, and correlated with a trend for recovery. Detection of rVSV-ΔG-SARS-CoV-2-S vaccine RNA was noted in the regional iliac lymph node in animals assigned to the high-dose group, at both termination time points. A significant increase in binding and neutralizing antibody titers was observed following vaccination at both vaccine doses. In view of the findings, it was concluded that the rVSV-ΔG-SARS-CoV-2-S vaccine is safe. These results supported the initiation of clinical trials.

3.
Nat Commun ; 13(1): 2237, 2022 04 25.
Article in English | MEDLINE | ID: covidwho-1805612

ABSTRACT

The global spread of SARS-CoV-2 led to major economic and health challenges worldwide. Revealing host genes essential for infection by multiple variants of SARS-CoV-2 can provide insights into the virus pathogenesis, and facilitate the development of novel therapeutics. Here, employing a genome-scale CRISPR screen, we provide a comprehensive data-set of cellular factors that are exploited by wild type SARS-CoV-2 as well as two additional recently emerged variants of concerns (VOCs), Alpha and Beta. We identified several host factors critical for SARS-CoV-2 infection, including various components belonging to the Clathrin-dependent transport pathway, ubiquitination, Heparan sulfate biogenesis and host phosphatidylglycerol biosynthesis. Comparative analysis of the different VOCs revealed the host factors KREMEN2 and SETDB1 as potential unique candidates required only to the Alpha variant. Furthermore, the analysis identified GATA6, a zinc finger transcription factor, as an essential proviral gene for all variants inspected. We show that GATA6 directly regulates ACE2 transcription and accordingly, is critical for SARS-CoV-2 cell entry. Analysis of clinical samples collected from SARS-CoV-2 infected individuals shows elevated levels of GATA6, suggesting a role in COVID-19 pathogenesis. Finally, pharmacological inhibition of GATA6 resulted in down-modulation of ACE2 and inhibition of viral infectivity. Overall, we show GATA6 may represent a target for the development of anti-SARS-CoV-2 therapeutic strategies and reaffirm the value of the CRISPR loss-of-function screens in providing a list of potential new targets for therapeutic interventions.


Subject(s)
Angiotensin-Converting Enzyme 2 , COVID-19 , Angiotensin-Converting Enzyme 2/genetics , COVID-19/genetics , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , GATA6 Transcription Factor/genetics , Humans , Peptidyl-Dipeptidase A/metabolism , Proviruses/genetics , SARS-CoV-2/genetics
4.
Sci Rep ; 12(1): 5758, 2022 04 06.
Article in English | MEDLINE | ID: covidwho-1778630

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causal agent of the COVID-19 pandemic. More than 274 million individuals have suffered from COVID-19 and over five million people have died from this disease so far. Therefore, there is an urgent need for therapeutic drugs. Repurposing FDA approved drugs should be favored since evaluation of safety and efficacy of de-novo drug design are both costly and time consuming. We report that imatinib, an Abl tyrosine kinase inhibitor, robustly decreases SARS-CoV-2 infection and uncover a mechanism of action. We show that imatinib inhibits the infection of SARS-CoV-2 and its surrogate lentivector pseudotype. In latter, imatinib inhibited both routes of viral entry, endocytosis and membrane-fusion. We utilized a system to quantify in real-time cell-cell membrane fusion mediated by the SARS-CoV-2 surface protein, Spike, and its receptor, hACE2, to demonstrate that imatinib inhibits this process in an Abl1 and Abl2 independent manner. Furthermore, cellular thermal shift assay revealed a direct imatinib-Spike interaction that affects Spike susceptibility to trypsin digest. Collectively, our data suggest that imatinib inhibits Spike mediated viral entry by an off-target mechanism. These findings mark imatinib as a promising therapeutic drug in inhibiting the early steps of SARS-CoV-2 infection.


Subject(s)
COVID-19 , COVID-19/drug therapy , Humans , Imatinib Mesylate/pharmacology , Pandemics , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Virus Internalization
5.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-330133

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing coronavirus disease 19 (COVID-19) pandemic. Despite its urgency, we still do not fully understand the molecular basis of SARS-CoV-2 pathogenesis and its ability to antagonize innate immune responses. SARS-CoV-2 leads to shutoff of cellular protein synthesis and over-expression of nsp1, a central shutoff factor in coronaviruses, inhibits cellular gene translation. However, the diverse molecular mechanisms nsp1 employs as well as its functional importance in infection are still unresolved. By overexpressing various nsp1 mutants and generating a SARS-CoV-2 mutant in which nsp1 does not bind ribosomes, we untangle the effects of nsp1. We uncover that nsp1, through inhibition of translation and induction of mRNA degradation, is the main driver of host shutoff during SARS-CoV-2 infection. Furthermore, we find the propagation of nsp1 mutant virus is inhibited specifically in cells with intact interferon (IFN) response as well as in-vivo, in infected hamsters, and this attenuation is associated with stronger induction of type I IFN response. This illustrates that nsp1 shutoff activity has an essential role mainly in counteracting the IFN response. Overall, our results reveal the multifaceted approach nsp1 uses to shut off cellular protein synthesis and uncover the central role it plays in SARS-CoV-2 pathogenesis, explicitly through blockage of the IFN response.

6.
Vaccines (Basel) ; 10(2)2022 Feb 14.
Article in English | MEDLINE | ID: covidwho-1699506

ABSTRACT

The emergence of rapidly spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a major challenge to the ability of vaccines and therapeutic antibodies to provide immunity. These variants contain mutations of specific amino acids that might impede vaccine efficacy. BriLife® (rVSV-ΔG-spike) is a newly developed SARS-CoV-2 vaccine candidate currently in phase II clinical trials. It is based on a replication-competent vesicular stomatitis virus (VSV) platform. The rVSV-ΔG-spike contains several spontaneously acquired spike mutations that correspond to SARS-CoV-2 variants' mutations. We show that human sera from BriLife® vaccinees preserve comparable neutralization titers towards alpha, gamma, and delta variants and show less than a three-fold reduction in the neutralization capacity of beta and omicron compared to the original virus. Taken together, we show that human sera from BriLife® vaccinees overall maintain a neutralizing antibody response against all tested variants. We suggest that BriLife®-acquired mutations may prove advantageous against future SARS-CoV-2 VOCs.

7.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-304759

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause for the ongoing COVID-19 pandemic1. The continued spread of SARS-CoV-2 along with the imminent flu season increase the probability of influenza-SARS-CoV-2 dual infection which might result in a severe disease. In this study, we examined the disease outcome of influenza A virus (IAV) and SARS-CoV-2 co-infection in K18-hACE2 mice. Our data indicates that IAV-infected mice are more susceptible to develop severe disease upon co-infection with SARS-CoV-2 two days post influenza infection. This co-infection results in severe morbidity and nearly uniform fatality as compared to the non-fatal influenza disease, or the partial fatality of SARS-CoV-2 alone. Co-infection was associated with elevated influenza viral load in respiratory organs. Remarkably, prior immunity to influenza, but not to SARS-CoV-2, prevented the severe disease and mortality. These data provide an experimental support that flu intervention by prior vaccination may be valuable in reducing the risk of sever Flu - SARS-CoV-2 comorbidity, and highlight the importance of vaccination.

8.
Arch Toxicol ; 96(3): 859-875, 2022 03.
Article in English | MEDLINE | ID: covidwho-1634984

ABSTRACT

rVSV-ΔG-SARS-CoV-2-S is a clinical stage (Phase 2) replication competent recombinant vaccine against SARS-CoV-2. To evaluate the safety profile of the vaccine, a series of non-clinical safety, immunogenicity and efficacy studies were conducted in four animal species, using multiple doses (up to 108 Plaque Forming Units/animal) and dosing regimens. There were no treatment-related mortalities or any noticeable clinical signs in any of the studies. Compared to unvaccinated controls, hematology and biochemistry parameters were unremarkable and no adverse histopathological findings. There was no detectable viral shedding in urine, nor viral RNA detected in whole blood or serum samples seven days post vaccination. The rVSV-ΔG-SARS-CoV-2-S vaccination gave rise to neutralizing antibodies, cellular immune responses, and increased lymphocytic cellularity in the spleen germinal centers and regional lymph nodes. No evidence for neurovirulence was found in C57BL/6 immune competent mice or in highly sensitive type I interferon knock-out mice. Vaccine virus replication and distribution in K18-human Angiotensin-converting enzyme 2-transgenic mice showed a gradual clearance from the vaccination site with no vaccine virus recovered from the lungs. The nonclinical data suggest that the rVSV-ΔG-SARS-CoV-2-S vaccine is safe and immunogenic. These results supported the initiation of clinical trials, currently in Phase 2.


Subject(s)
COVID-19 Vaccines/toxicity , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Vaccines/immunology , Cricetinae , Female , Membrane Glycoproteins/genetics , Mesocricetus , Mice , Mice, Inbred C57BL , Rabbits , Swine , Vaccination , Vaccines, Synthetic/toxicity , Viral Envelope Proteins/genetics
9.
Viruses ; 14(2)2022 01 19.
Article in English | MEDLINE | ID: covidwho-1625815

ABSTRACT

SARS-CoV-2, a member of the coronavirus family, is the causative agent of the COVID-19 pandemic. Currently, there is still an urgent need in developing an efficient therapeutic intervention. In this study, we aimed at evaluating the therapeutic effect of a single intranasal treatment of the TLR3/MDA5 synthetic agonist Poly(I:C) against a lethal dose of SARS-CoV-2 in K18-hACE2 transgenic mice. We demonstrate here that early Poly(I:C) treatment acts synergistically with SARS-CoV-2 to induce an intense, immediate and transient upregulation of innate immunity-related genes in lungs. This effect is accompanied by viral load reduction, lung and brain cytokine storms prevention and increased levels of macrophages and NK cells, resulting in 83% mice survival, concomitantly with long-term immunization. Thus, priming the lung innate immunity by Poly(I:C) or alike may provide an immediate, efficient and safe protective measure against SARS-CoV-2 infection.


Subject(s)
COVID-19/immunology , COVID-19/prevention & control , Immunity, Innate , Poly I-C/immunology , Poly I-C/therapeutic use , SARS-CoV-2/drug effects , Toll-Like Receptor 3/agonists , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/immunology , Animals , COVID-19/drug therapy , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/prevention & control , Disease Models, Animal , Female , Humans , Lung/immunology , Lung/virology , Mice , Mice, Transgenic , SARS-CoV-2/immunology , Toll-Like Receptor 3/immunology , Viral Load/drug effects
10.
Viruses ; 14(1)2021 12 21.
Article in English | MEDLINE | ID: covidwho-1580414

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a severe global pandemic. Mice models are essential to investigate infection pathology, antiviral drugs, and vaccine development. However, wild-type mice lack the human angiotensin-converting enzyme 2 (hACE2) that mediates SARS-CoV-2 entry into human cells and consequently are not susceptible to SARS-CoV-2 infection. hACE2 transgenic mice could provide an efficient COVID-19 model, but are not always readily available, and practically restricted to specific strains. Therefore, there is a dearth of additional mouse models for SARS-CoV-2 infection. We applied lentiviral vectors to generate hACE2 expression in interferon receptor knock-out (IFNAR1-/-) mice. Lenti-hACE2 transduction supported SARS-CoV-2 replication in vivo, simulating mild acute lung disease. Gene expression analysis revealed two modes of immune responses to SARS-CoV-2 infection: one in response to the exposure of mouse lungs to SARS-CoV-2 particles in the absence of productive viral replication, and the second in response to productive SARS-CoV-2 infection. Our results infer that immune response to immunogenic elements on incoming virus or in productively infected cells stimulate diverse immune effectors, even in absence of type I IFN signaling. Our findings should contribute to a better understanding of the immune response triggered by SARS-CoV-2 and to further elucidate COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , COVID-19/immunology , Disease Models, Animal , Lentivirus/genetics , SARS-CoV-2/physiology , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/virology , Cell Line , Humans , Immunity/genetics , Lung/immunology , Lung/virology , Mice , Mice, Transgenic , Receptor, Interferon alpha-beta/genetics , Transduction, Genetic , Virus Replication
11.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-293181

ABSTRACT

BriLife® (rVSV- ΔG-spike) is a SARS-CoV-2 vaccine candidate based on vesicular stomatitis virus (VSV) platform. We show that sera from BriLife® vaccinees maintain neutralization capacity against alpha, beta, gamma and delta SARS-CoV-2 variants. BriLife® spontaneously-acquired spike mutations, corresponding with key SARS-CoV-2 variants mutations, may contribute to its efficacy against SARS-CoV-2 variants.

12.
Front Bioeng Biotechnol ; 9: 737627, 2021.
Article in English | MEDLINE | ID: covidwho-1477802

ABSTRACT

The COVID-19 pandemic initiated a worldwide race toward the development of treatments and vaccines. Small animal models included the Syrian golden hamster and the K18-hACE2 mice infected with SARS-CoV-2 to display a disease state with some aspects of human COVID-19. A group activity of animals in their home cage continuously monitored by the HCMS100 (Home cage Monitoring System 100) was used as a sensitive marker of disease, successfully detecting morbidity symptoms of SARS-CoV-2 infection in hamsters and in K18-hACE2 mice. COVID-19 convalescent hamsters rechallenged with SARS-CoV-2 exhibited minor reduction in group activity compared to naive hamsters. To evaluate the rVSV-ΔG-spike vaccination efficacy against SARS-CoV-2, we used the HCMS100 to monitor the group activity of hamsters in their home cage. A single-dose rVSV-ΔG-spike vaccination of the immunized group showed a faster recovery than the nonimmunized infected hamsters, substantiating the efficacy of rVSV-ΔG-spike vaccine. HCMS100 offers nonintrusive, hands-free monitoring of a number of home cages of hamsters or mice modeling COVID-19.

13.
Nat Commun ; 12(1): 5819, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1454763

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing coronavirus disease 2019 (COVID-19) pandemic. The continued spread of SARS-CoV-2 increases the probability of influenza/SARS-CoV-2 coinfection, which may result in severe disease. In this study, we examine the disease outcome of influenza A virus (IAV) and SARS-CoV-2 coinfection in K18-hACE2 mice. Our data indicate enhance susceptibility of IAV-infected mice to developing severe disease upon coinfection with SARS-CoV-2 two days later. In contrast to nonfatal influenza and lower mortality rates due to SARS-CoV-2 alone, this coinfection results in severe morbidity and nearly complete mortality. Coinfection is associated with elevated influenza viral loads in respiratory organs. Remarkably, prior immunity to influenza, but not to SARS-CoV-2, prevents severe disease and mortality. This protection is antibody-dependent. These data experimentally support the necessity of seasonal influenza vaccination for reducing the risk of severe influenza/COVID-19 comorbidity during the COVID-19 pandemic.


Subject(s)
COVID-19/immunology , COVID-19/virology , Coinfection/immunology , Coinfection/virology , Immunity , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/virology , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Viral/immunology , COVID-19/pathology , Cell Line , Disease Models, Animal , Female , Humans , Inflammation/genetics , Lung/pathology , Lung/virology , Male , Mice, Inbred C57BL , Mice, Transgenic , Up-Regulation/genetics , Viral Load/immunology
14.
Cell Rep ; 36(10): 109679, 2021 09 07.
Article in English | MEDLINE | ID: covidwho-1363916

ABSTRACT

A wide range of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing monoclonal antibodies (mAbs) have been reported, most of which target the spike glycoprotein. Therapeutic implementation of these antibodies has been challenged by emerging SARS-CoV-2 variants harboring mutated spike versions. Consequently, re-assessment of previously identified mAbs is of high priority. Four previously selected mAbs targeting non-overlapping epitopes are now evaluated for binding potency to mutated RBD versions, reported to mediate escape from antibody neutralization. In vitro neutralization potencies of these mAbs, and two NTD-specific mAbs, are evaluated against two frequent SARS-CoV-2 variants of concern, the B.1.1.7 Alpha and the B.1.351 Beta. Furthermore, we demonstrate therapeutic potential of three selected mAbs by treatment of K18-human angiotensin-converting enzyme 2 (hACE2) transgenic mice 2 days post-infection with each virus variant. Thus, despite the accumulation of spike mutations, the highly potent MD65 and BL6 mAbs retain their ability to bind the prevalent viral mutants, effectively protecting against B.1.1.7 and B.1.351 variants.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/chemistry , Antibodies, Neutralizing/administration & dosage , Antibodies, Neutralizing/chemistry , Antibody Affinity , COVID-19/therapy , COVID-19/virology , Epitopes/genetics , Epitopes/immunology , Humans , Immunization, Passive , Mice , Mice, Transgenic , Models, Molecular , Neutralization Tests , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Treatment Outcome
15.
J Infect Dis ; 224(4): 616-619, 2021 08 16.
Article in English | MEDLINE | ID: covidwho-1358460

ABSTRACT

Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may influence the effectiveness of existing laboratory diagnostics. In the current study we determined whether the British (20I/501Y.V1) and South African (20H/501Y.V2) SARS-CoV-2 variants of concern are detected with an in-house S1-based antigen detection assay, analyzing spiked pools of quantitative reverse-transcription polymerase chain reaction-negative nasopharyngeal swab specimens. The assay, combining 4 monoclonal antibodies, allowed sensitive detection of both the wild type and the variants of concern, despite accumulation of several mutations in the variants' S1 region-results suggesting that this combination, targeting distinct epitopes, enables both specificity and the universality.


Subject(s)
COVID-19/diagnosis , COVID-19/virology , SARS-CoV-2/classification , Antibodies, Monoclonal/immunology , Antigens, Viral/immunology , Antigens, Viral/isolation & purification , COVID-19/immunology , Humans , Mutation , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/isolation & purification , Viral Load
16.
Nat Biotechnol ; 39(12): 1556-1562, 2021 12.
Article in English | MEDLINE | ID: covidwho-1287813

ABSTRACT

Frequent testing of large population groups combined with contact tracing and isolation measures will be crucial for containing Coronavirus Disease 2019 outbreaks. Here we present LAMP-Seq, a modified, highly scalable reverse transcription loop-mediated isothermal amplification (RT-LAMP) method. Unpurified biosamples are barcoded and amplified in a single heat step, and pooled products are analyzed en masse by sequencing. Using commercial reagents, LAMP-Seq has a limit of detection of ~2.2 molecules per µl at 95% confidence and near-perfect specificity for severe acute respiratory syndrome coronavirus 2 given its sequence readout. Clinical validation of an open-source protocol with 676 swab samples, 98 of which were deemed positive by standard RT-qPCR, demonstrated 100% sensitivity in individuals with cycle threshold values of up to 33 and a specificity of 99.7%, at a very low material cost. With a time-to-result of fewer than 24 h, low cost and little new infrastructure requirement, LAMP-Seq can be readily deployed for frequent testing as part of an integrated public health surveillance program.


Subject(s)
COVID-19 Testing/methods , COVID-19 , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , COVID-19/diagnosis , Humans
17.
Cell Rep ; 35(13): 109305, 2021 06 29.
Article in English | MEDLINE | ID: covidwho-1260679

ABSTRACT

The human leukocyte antigen (HLA)-bound viral antigens serve as an immunological signature that can be selectively recognized by T cells. As viruses evolve by acquiring mutations, it is essential to identify a range of presented viral antigens. Using HLA peptidomics, we are able to identify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-derived peptides presented by highly prevalent HLA class I (HLA-I) molecules by using infected cells as well as overexpression of SARS-CoV-2 genes. We find 26 HLA-I peptides and 36 HLA class II (HLA-II) peptides. Among the identified peptides, some are shared between different cells and some are derived from out-of-frame open reading frames (ORFs). Seven of these peptides were previously shown to be immunogenic, and we identify two additional immunoreactive peptides by using HLA multimer staining. These results may aid the development of the next generation of SARS-CoV-2 vaccines based on presented viral-specific antigens that span several of the viral genes.


Subject(s)
Antigens, Viral/immunology , COVID-19/immunology , COVID-19/virology , Peptides/immunology , SARS-CoV-2/immunology , Antigen Presentation , Antigens, Viral/metabolism , COVID-19 Vaccines , Cell Line , Epitopes, T-Lymphocyte/immunology , HEK293 Cells , Histocompatibility Antigens Class I/immunology , Histocompatibility Antigens Class II/immunology , Humans , Peptidomimetics , SARS-CoV-2/genetics , T-Lymphocytes
18.
Nature ; 594(7862): 240-245, 2021 06.
Article in English | MEDLINE | ID: covidwho-1225510

ABSTRACT

The coronavirus SARS-CoV-2 is the cause of the ongoing pandemic of COVID-191. Coronaviruses have developed a variety of mechanisms to repress host mRNA translation to allow the translation of viral mRNA, and concomitantly block the cellular innate immune response2,3. Although several different proteins of SARS-CoV-2 have previously been implicated in shutting off host expression4-7, a comprehensive picture of the effects of SARS-CoV-2 infection on cellular gene expression is lacking. Here we combine RNA sequencing, ribosome profiling and metabolic labelling of newly synthesized RNA to comprehensively define the mechanisms that are used by SARS-CoV-2 to shut off cellular protein synthesis. We show that infection leads to a global reduction in translation, but that viral transcripts are not preferentially translated. Instead, we find that infection leads to the accelerated degradation of cytosolic cellular mRNAs, which facilitates viral takeover of the mRNA pool in infected cells. We reveal that the translation of transcripts that are induced in response to infection (including innate immune genes) is impaired. We demonstrate this impairment is probably mediated by inhibition of nuclear mRNA export, which prevents newly transcribed cellular mRNA from accessing ribosomes. Overall, our results uncover a multipronged strategy that is used by SARS-CoV-2 to take over the translation machinery and to suppress host defences.


Subject(s)
COVID-19/metabolism , COVID-19/virology , Host-Pathogen Interactions , Protein Biosynthesis , SARS-CoV-2/pathogenicity , 5' Untranslated Regions/genetics , COVID-19/genetics , COVID-19/immunology , Cell Line , Host-Pathogen Interactions/genetics , Host-Pathogen Interactions/immunology , Humans , Immunity, Innate/genetics , Protein Biosynthesis/genetics , RNA Stability , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Viral/metabolism , Ribosomes/metabolism , Viral Nonstructural Proteins/metabolism
19.
J Biol Chem ; 296: 100470, 2021.
Article in English | MEDLINE | ID: covidwho-1101336

ABSTRACT

The ongoing COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major threat to global health. Vaccines are ideal solutions to prevent infection, but treatments are also needed for those who have contracted the virus to limit negative outcomes, when vaccines are not applicable. Viruses must cross host cell membranes during their life cycle, creating a dependency on processes involving membrane dynamics. Thus, in this study, we examined whether the synthetic machinery for glycosphingolipids, biologically active components of cell membranes, can serve as a therapeutic target to combat SARS-CoV-2. We examined the antiviral effect of two specific inhibitors of glucosylceramide synthase (GCS): (i) Genz-123346, an analogue of the United States Food and Drug Administration-approved drug Cerdelga and (ii) GENZ-667161, an analogue of venglustat, which is currently under phase III clinical trials. We found that both GCS inhibitors inhibit replication of SARS-CoV-2. Moreover, these inhibitors also disrupt replication of influenza virus A/PR/8/34 (H1N1). Our data imply that synthesis of glycosphingolipids is necessary to support viral life cycles and suggest that GCS inhibitors should be further explored as antiviral therapies.


Subject(s)
Antiviral Agents/pharmacology , Carbamates/pharmacology , Dioxanes/pharmacology , Glucosyltransferases/antagonists & inhibitors , Glycosphingolipids/antagonists & inhibitors , Influenza A Virus, H1N1 Subtype/drug effects , Pyrrolidines/pharmacology , Quinuclidines/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/chemical synthesis , COVID-19/drug therapy , COVID-19/enzymology , COVID-19/virology , Carbamates/chemical synthesis , Cell Membrane/drug effects , Cell Membrane/enzymology , Cell Membrane/virology , Chlorocebus aethiops , Clinical Trials, Phase III as Topic , Dioxanes/chemical synthesis , Dogs , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Gene Expression Regulation , Glucosyltransferases/genetics , Glucosyltransferases/metabolism , Glycosphingolipids/biosynthesis , Host-Pathogen Interactions/genetics , Humans , Influenza A Virus, H1N1 Subtype/growth & development , Influenza A Virus, H1N1 Subtype/metabolism , Influenza, Human/drug therapy , Influenza, Human/enzymology , Influenza, Human/virology , Madin Darby Canine Kidney Cells , Pyrrolidines/chemical synthesis , Quinuclidines/chemical synthesis , SARS-CoV-2/growth & development , SARS-CoV-2/metabolism , Signal Transduction , Vero Cells , Virus Replication/drug effects
20.
ACS Nano ; 15(6): 9627-9637, 2021 06 22.
Article in English | MEDLINE | ID: covidwho-1041859

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the causal agent of COVID-19 and stands at the center of the current global human pandemic, with death toll exceeding one million. The urgent need for a vaccine has led to the development of various immunization approaches. mRNA vaccines represent a cell-free, simple, and rapid platform for immunization, and therefore have been employed in recent studies toward the development of a SARS-CoV-2 vaccine. Herein, we present the design of an mRNA vaccine, based on lipid nanoparticles (LNPs)-encapsulated SARS-CoV-2 human Fc-conjugated receptor-binding domain (RBD-hFc). Several ionizable lipids have been evaluated in vivo in a luciferase (luc) mRNA reporter assay, and two leading LNPs formulations have been chosen for the subsequent RBD-hFc mRNA vaccine strategy. Intramuscular administration of LNP RBD-hFc mRNA elicited robust humoral response, a high level of neutralizing antibodies and a Th1-biased cellular response in BALB/c mice. The data in the current study demonstrate the potential of these lipids as promising candidates for LNP-based mRNA vaccines in general and for a COVID19 vaccine in particular.


Subject(s)
COVID-19 , Nanoparticles , Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19 Vaccines , Humans , Lipids , Mice , Mice, Inbred BALB C , RNA, Messenger/genetics , SARS-CoV-2 , Spike Glycoprotein, Coronavirus
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