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1.
PLoS Biol ; 19(12): e3001490, 2021 12.
Article in English | MEDLINE | ID: covidwho-1595018

ABSTRACT

Over the past 20 years, 3 highly pathogenic human coronaviruses (HCoVs) have emerged-Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and, most recently, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)-demonstrating that coronaviruses (CoVs) pose a serious threat to human health and highlighting the importance of developing effective therapies against them. Similar to other viruses, CoVs are dependent on host factors for their survival and replication. We hypothesized that evolutionarily distinct CoVs may exploit similar host factors and pathways to support their replication cycles. Herein, we conducted 2 independent genome-wide CRISPR/Cas-9 knockout (KO) screens to identify MERS-CoV and HCoV-229E host dependency factors (HDFs) required for HCoV replication in the human Huh7 cell line. Top scoring genes were further validated and assessed in the context of MERS-CoV and HCoV-229E infection as well as SARS-CoV and SARS-CoV-2 infection. Strikingly, we found that several autophagy-related genes, including TMEM41B, MINAR1, and the immunophilin FKBP8, were common host factors required for pan-CoV replication. Importantly, inhibition of the immunophilin protein family with the compounds cyclosporine A, and the nonimmunosuppressive derivative alisporivir, resulted in dose-dependent inhibition of CoV replication in primary human nasal epithelial cell cultures, which recapitulate the natural site of virus replication. Overall, we identified host factors that are crucial for CoV replication and demonstrated that these factors constitute potential targets for therapeutic intervention by clinically approved drugs.


Subject(s)
Autophagy/genetics , CRISPR-Cas Systems , Middle East Respiratory Syndrome Coronavirus/genetics , SARS-CoV-2/genetics , Antiviral Agents/pharmacology , Gene Knockdown Techniques , Host-Pathogen Interactions , Humans , Middle East Respiratory Syndrome Coronavirus/drug effects , Middle East Respiratory Syndrome Coronavirus/physiology , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Virus Replication
2.
Nature ; 2021 Dec 22.
Article in English | MEDLINE | ID: covidwho-1585832

ABSTRACT

Emerging variants of concern (VOC) drive the SARS-CoV-2 pandemic1,2. Experimental assessment of replication and transmission of major VOC compared to progenitors are needed to understand successful emerging mechanisms of VOC3. Here, we show that Alpha and Beta spike (S) proteins have a greater affinity to human angiotensin converting enzyme 2 (hACE2) receptor over the progenitor variant (wt-S614G) in vitro. Yet Alpha and wt-S614G had similar replication kinetics in human nasal airway epithelial cultures, whereas Beta was outcompeted by both. In vivo, competition experiments showed a clear fitness advantage of Alpha over the progenitor variant (wt-S614G) in ferrets and two mouse models, where the substitutions in S were major drivers for fitness advantage. In hamsters, supporting high replication levels, Alpha and wt-S614G had comparable fitness. In contrast, Beta was outcompeted by Alpha and wt-S614G in hamsters and hACE2-expressing mice. Our study highlights the importance of using multiple models for complete fitness characterization of VOC and demonstrates adaptation of Alpha towards increased upper respiratory tract replication and enhanced transmission in vivo in restrictive models, whereas Beta fails to overcome contemporary strains in naïve animals.

3.
Nat Commun ; 12(1): 7276, 2021 12 14.
Article in English | MEDLINE | ID: covidwho-1575708

ABSTRACT

Double membrane vesicles (DMVs) serve as replication organelles of plus-strand RNA viruses such as hepatitis C virus (HCV) and SARS-CoV-2. Viral DMVs are morphologically analogous to DMVs formed during autophagy, but lipids driving their biogenesis are largely unknown. Here we show that production of the lipid phosphatidic acid (PA) by acylglycerolphosphate acyltransferase (AGPAT) 1 and 2 in the ER is important for DMV biogenesis in viral replication and autophagy. Using DMVs in HCV-replicating cells as model, we found that AGPATs are recruited to and critically contribute to HCV and SARS-CoV-2 replication and proper DMV formation. An intracellular PA sensor accumulated at viral DMV formation sites, consistent with elevated levels of PA in fractions of purified DMVs analyzed by lipidomics. Apart from AGPATs, PA is generated by alternative pathways and their pharmacological inhibition also impaired HCV and SARS-CoV-2 replication as well as formation of autophagosome-like DMVs. These data identify PA as host cell lipid involved in proper replication organelle formation by HCV and SARS-CoV-2, two phylogenetically disparate viruses causing very different diseases, i.e. chronic liver disease and COVID-19, respectively. Host-targeting therapy aiming at PA synthesis pathways might be suitable to attenuate replication of these viruses.


Subject(s)
Hepacivirus/genetics , Phosphatidic Acids/metabolism , SARS-CoV-2/genetics , Virus Replication/physiology , 1-Acylglycerol-3-Phosphate O-Acyltransferase , Acyltransferases , Autophagosomes/metabolism , Autophagy , COVID-19/virology , Cell Line , Cell Survival , Dengue Virus , HEK293 Cells , Humans , Membrane Proteins , Spike Glycoprotein, Coronavirus , Viral Nonstructural Proteins , Viral Proteins , Zika Virus
5.
Proc Natl Acad Sci U S A ; 118(49)2021 12 07.
Article in English | MEDLINE | ID: covidwho-1541316

ABSTRACT

As coronaviruses (CoVs) replicate in the host cell cytoplasm, they rely on their own capping machinery to ensure the efficient translation of their messenger RNAs (mRNAs), protect them from degradation by cellular 5' exoribonucleases (ExoNs), and escape innate immune sensing. The CoV nonstructural protein 14 (nsp14) is a bifunctional replicase subunit harboring an N-terminal 3'-to-5' ExoN domain and a C-terminal (N7-guanine)-methyltransferase (N7-MTase) domain that is presumably involved in viral mRNA capping. Here, we aimed to integrate structural, biochemical, and virological data to assess the importance of conserved N7-MTase residues for nsp14's enzymatic activities and virus viability. We revisited the crystal structure of severe acute respiratory syndrome (SARS)-CoV nsp14 to perform an in silico comparative analysis between betacoronaviruses. We identified several residues likely involved in the formation of the N7-MTase catalytic pocket, which presents a fold distinct from the Rossmann fold observed in most known MTases. Next, for SARS-CoV and Middle East respiratory syndrome CoV, site-directed mutagenesis of selected residues was used to assess their importance for in vitro enzymatic activity. Most of the engineered mutations abolished N7-MTase activity, while not affecting nsp14-ExoN activity. Upon reverse engineering of these mutations into different betacoronavirus genomes, we identified two substitutions (R310A and F426A in SARS-CoV nsp14) abrogating virus viability and one mutation (H424A) yielding a crippled phenotype across all viruses tested. Our results identify the N7-MTase as a critical enzyme for betacoronavirus replication and define key residues of its catalytic pocket that can be targeted to design inhibitors with a potential pan-coronaviral activity spectrum.

6.
Preprint in English | EuropePMC | ID: ppcovidwho-293083

ABSTRACT

Rhinoviruses (RV) and inhaled allergens, such as house dust mite (HDM) are the major agents responsible for asthma onset, its life-threatening exacerbations and progression to severe disease. The role of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in exacerbations of asthma or the influence of preexisting viral or allergic airway inflammation on the development of coronavirus disease 2019 (COVID-19) is largely unknown. To address this, we compared molecular mechanisms of HDM, RV and SARS-CoV-2 interactions in experimental RV infection in patients with asthma and healthy individuals. RV infection was sensed via retinoic acid-inducible gene I (RIG-I) helicase, but not via NLR family pyrin domain containing 3 (NLRP3), which led to subsequent apoptosis-associated speck like protein containing a caspase recruitment domain (ASC) recruitment, oligomerization and RIG-I inflammasome activation. This phenomenon was augmented in bronchial epithelium in patients with asthma, especially upon pre-exposure to HDM, which itself induced a priming step, pro-IL-1β release and early inhibition of RIG-I/TANK binding kinase 1/IκB kinase ϵ/type I/III interferons (RIG-I/TBK1/IKKϵ/IFN-I/III) responses. Excessive activation of RIG-I inflammasomes was partially responsible for the alteration and persistence of type I/III IFN responses, prolonged viral clearance and unresolved inflammation in asthma. RV/HDM-induced sustained IFN I/III responses initially restricted SARS-CoV-2 replication in epithelium of patients with asthma, but even this limited infection with SARS-CoV-2 augmented RIG-I inflammasome activation. Timely inhibition of the epithelial RIG-I inflammasome and reduction of IL-1β signaling may lead to more efficient viral clearance and lower the burden of RV and SARS-CoV-2 infection.

7.
Cell Rep Med ; : 100456, 2021 Nov 04.
Article in English | MEDLINE | ID: covidwho-1500334

ABSTRACT

The ongoing SARS-CoV-2 pandemic continues to lead to high morbidity and mortality. During pregnancy, severe maternal and neonatal outcomes and placental pathological changes have been described. We evaluate SARS-CoV-2 infection at the maternal-fetal interface using precision-cut slices (PCSs) of human placenta. Remarkably, exposure of placenta PCSs to SARS-CoV-2 leads to a full replication cycle with infectious virus release. Moreover, the susceptibility of placental tissue to SARS-CoV-2 replication relates to the expression levels of ACE2. Viral proteins and/or RNA are detected in syncytiotrophoblast, cytotrophoblasts, villous stroma, and possibly Hofbauer cells. While SARS-CoV-2 infection of placenta PCSs does not cause a detectable cytotoxicity nor a pro-inflammatory cytokine response, an upregulation of one order of magnitude of interferon type III transcripts is measured. In conclusion, our data demonstrate the capacity of SARS-CoV-2 to infect and propagate in human placenta and constitute a basis for further investigation of SARS-CoV-2 biology at the maternal-fetal interface.

9.
Cell Rep ; 37(2): 109814, 2021 10 12.
Article in English | MEDLINE | ID: covidwho-1433045

ABSTRACT

Control of the ongoing SARS-CoV-2 pandemic is endangered by the emergence of viral variants with increased transmission efficiency, resistance to marketed therapeutic antibodies, and reduced sensitivity to vaccine-induced immunity. Here, we screen B cells from COVID-19 donors and identify P5C3, a highly potent and broadly neutralizing monoclonal antibody with picomolar neutralizing activity against all SARS-CoV-2 variants of concern (VOCs) identified to date. Structural characterization of P5C3 Fab in complex with the spike demonstrates a neutralizing activity defined by a large buried surface area, highly overlapping with the receptor-binding domain (RBD) surface necessary for ACE2 interaction. We further demonstrate that P5C3 shows complete prophylactic protection in the SARS-CoV-2-infected hamster challenge model. These results indicate that P5C3 opens exciting perspectives either as a prophylactic agent in immunocompromised individuals with poor response to vaccination or as combination therapy in SARS-CoV-2-infected individuals.


Subject(s)
Broadly Neutralizing Antibodies/therapeutic use , COVID-19/drug therapy , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , B-Lymphocytes/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/immunology , Cell Line , Cricetinae , Disease Models, Animal , Epitopes/immunology , Humans , Immunoglobulin Fab Fragments/immunology , Immunoglobulin Fab Fragments/metabolism , Neutralization Tests , Protein Binding/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/ultrastructure , Structure-Activity Relationship , Vaccination
10.
Cell Rep ; 36(5): 109493, 2021 08 03.
Article in English | MEDLINE | ID: covidwho-1328703

ABSTRACT

Safe and effective vaccines are urgently needed to stop the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We construct a series of live attenuated vaccine candidates by large-scale recoding of the SARS-CoV-2 genome and assess their safety and efficacy in Syrian hamsters. Animals were vaccinated with a single dose of the respective recoded virus and challenged 21 days later. Two of the tested viruses do not cause clinical symptoms but are highly immunogenic and induce strong protective immunity. Attenuated viruses replicate efficiently in the upper but not in the lower airways, causing only mild pulmonary histopathology. After challenge, hamsters develop no signs of disease and rapidly clear challenge virus: at no time could infectious virus be recovered from the lungs of infected animals. The ease with which attenuated virus candidates can be produced and administered favors their further development as vaccines to combat the ongoing pandemic.


Subject(s)
COVID-19 Vaccines , COVID-19/immunology , COVID-19/prevention & control , Respiratory System/pathology , Respiratory System/virology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Animals , Chlorocebus aethiops , Gene Editing , Genome, Viral , Humans , Immunity , Mesocricetus , Mutation , Pandemics/prevention & control , Vaccines, Attenuated , Vero Cells , Virus Replication
11.
Emerg Infect Dis ; 27(7): 1811-1820, 2021 07.
Article in English | MEDLINE | ID: covidwho-1278358

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally, and the number of worldwide cases continues to rise. The zoonotic origins of SARS-CoV-2 and its intermediate and potential spillback host reservoirs, besides humans, remain largely unknown. Because of ethical and experimental constraints and more important, to reduce and refine animal experimentation, we used our repository of well-differentiated airway epithelial cell (AEC) cultures from various domesticated and wildlife animal species to assess their susceptibility to SARS-CoV-2. We observed that SARS-CoV-2 replicated efficiently only in monkey and cat AEC culture models. Whole-genome sequencing of progeny viruses revealed no obvious signs of nucleotide transitions required for SARS-CoV-2 to productively infect monkey and cat AEC cultures. Our findings, together with previous reports of human-to-animal spillover events, warrant close surveillance to determine the potential role of cats, monkeys, and closely related species as spillback reservoirs for SARS-CoV-2.


Subject(s)
Animals, Wild , COVID-19 , Animals , Epithelial Cells , Humans , Respiratory System , SARS-CoV-2
13.
Science ; 372(6548): 1306-1313, 2021 06 18.
Article in English | MEDLINE | ID: covidwho-1228853

ABSTRACT

Programmed ribosomal frameshifting is a key event during translation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA genome that allows synthesis of the viral RNA-dependent RNA polymerase and downstream proteins. Here, we present the cryo-electron microscopy structure of a translating mammalian ribosome primed for frameshifting on the viral RNA. The viral RNA adopts a pseudoknot structure that lodges at the entry to the ribosomal messenger RNA (mRNA) channel to generate tension in the mRNA and promote frameshifting, whereas the nascent viral polyprotein forms distinct interactions with the ribosomal tunnel. Biochemical experiments validate the structural observations and reveal mechanistic and regulatory features that influence frameshifting efficiency. Finally, we compare compounds previously shown to reduce frameshifting with respect to their ability to inhibit SARS-CoV-2 replication, establishing coronavirus frameshifting as a target for antiviral intervention.


Subject(s)
Frameshifting, Ribosomal , RNA, Viral/genetics , Ribosomes/ultrastructure , SARS-CoV-2/genetics , Viral Proteins/biosynthesis , Animals , Antiviral Agents/pharmacology , Codon, Terminator , Coronavirus RNA-Dependent RNA Polymerase/biosynthesis , Coronavirus RNA-Dependent RNA Polymerase/chemistry , Coronavirus RNA-Dependent RNA Polymerase/genetics , Cryoelectron Microscopy , Fluoroquinolones/pharmacology , Frameshifting, Ribosomal/drug effects , Genome, Viral , Humans , Image Processing, Computer-Assisted , Models, Molecular , Nucleic Acid Conformation , Open Reading Frames , Protein Folding , RNA, Messenger/chemistry , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Ribosomal, 18S/chemistry , RNA, Ribosomal, 18S/genetics , RNA, Ribosomal, 18S/metabolism , RNA, Viral/chemistry , RNA, Viral/metabolism , Ribosomal Proteins/metabolism , Ribosomes/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Viral Proteins/chemistry , Viral Proteins/genetics , Virus Replication/drug effects
14.
Front Cell Infect Microbiol ; 11: 644574, 2021.
Article in English | MEDLINE | ID: covidwho-1207695

ABSTRACT

Vaccines are essential to control the spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and to protect the vulnerable population. However, one safety concern of vaccination is the possible development of antibody-dependent enhancement (ADE) of SARS-CoV-2 infection. The potential infection of Fc receptor bearing cells such as macrophages, would support continued virus replication and inflammatory responses, and thereby potentially worsen the clinical outcome of COVID-19. Here we demonstrate that SARS-CoV-2 and SARS-CoV neither infect human monocyte-derived macrophages (hMDM) nor induce inflammatory cytokines in these cells, in sharp contrast to Middle East respiratory syndrome (MERS) coronavirus and the common cold human coronavirus 229E. Furthermore, serum from convalescent COVID-19 patients neither induced enhancement of SARS-CoV-2 infection nor innate immune response in hMDM. Although, hMDM expressed angiotensin-converting enzyme 2, no or very low levels of transmembrane protease serine 2 were found. These results support the view that ADE may not be involved in the immunopathological processes associated with COVID-19, however, more studies are necessary to understand the potential contribution of antibodies-virus complexes with other cells expressing FcR receptors.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Antibodies, Viral , Humans , Macrophages , SARS-CoV-2
15.
EMBO J ; 40(11): e102277, 2021 06 01.
Article in English | MEDLINE | ID: covidwho-1194823

ABSTRACT

The ongoing outbreak of severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) demonstrates the continuous threat of emerging coronaviruses (CoVs) to public health. SARS-CoV-2 and SARS-CoV share an otherwise non-conserved part of non-structural protein 3 (Nsp3), therefore named as "SARS-unique domain" (SUD). We previously found a yeast-2-hybrid screen interaction of the SARS-CoV SUD with human poly(A)-binding protein (PABP)-interacting protein 1 (Paip1), a stimulator of protein translation. Here, we validate SARS-CoV SUD:Paip1 interaction by size-exclusion chromatography, split-yellow fluorescent protein, and co-immunoprecipitation assays, and confirm such interaction also between the corresponding domain of SARS-CoV-2 and Paip1. The three-dimensional structure of the N-terminal domain of SARS-CoV SUD ("macrodomain II", Mac2) in complex with the middle domain of Paip1, determined by X-ray crystallography and small-angle X-ray scattering, provides insights into the structural determinants of the complex formation. In cellulo, SUD enhances synthesis of viral but not host proteins via binding to Paip1 in pBAC-SARS-CoV replicon-transfected cells. We propose a possible mechanism for stimulation of viral translation by the SUD of SARS-CoV and SARS-CoV-2.


Subject(s)
Coronavirus Papain-Like Proteases/metabolism , Gene Expression Regulation, Viral , Peptide Initiation Factors/metabolism , RNA-Binding Proteins/metabolism , RNA-Dependent RNA Polymerase/metabolism , SARS Virus/physiology , SARS-CoV-2/physiology , Viral Nonstructural Proteins/metabolism , Amino Acid Sequence , Bacterial Proteins , Chromatography, Gel , Coronavirus Papain-Like Proteases/chemistry , Crystallography, X-Ray , Genes, Reporter , HEK293 Cells , Humans , Immunoprecipitation , Luminescent Proteins , Models, Molecular , Peptide Initiation Factors/chemistry , Protein Binding , Protein Biosynthesis , Protein Conformation , Protein Domains , Protein Interaction Mapping , RNA, Viral/genetics , RNA-Binding Proteins/chemistry , RNA-Dependent RNA Polymerase/chemistry , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Ribosome Subunits/metabolism , SARS Virus/genetics , SARS-CoV-2/genetics , Scattering, Small Angle , Sequence Alignment , Sequence Homology, Amino Acid , Viral Nonstructural Proteins/chemistry , X-Ray Diffraction
16.
J Med Chem ; 64(9): 5632-5644, 2021 05 13.
Article in English | MEDLINE | ID: covidwho-1193564

ABSTRACT

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


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 229E, Human/drug effects , Coronavirus 229E, Human/enzymology , Endoribonucleases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Oleanolic Acid/analogs & derivatives , Viral Nonstructural Proteins/antagonists & inhibitors , Virus Replication/drug effects , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Cell Line , Dose-Response Relationship, Drug , Endoribonucleases/metabolism , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , Microbial Sensitivity Tests , Models, Molecular , Oleanolic Acid/chemical synthesis , Oleanolic Acid/chemistry , Oleanolic Acid/pharmacology , Viral Nonstructural Proteins/metabolism
17.
Nature ; 594(7862): 246-252, 2021 06.
Article in English | MEDLINE | ID: covidwho-1180252

ABSTRACT

The emergence and global spread of SARS-CoV-2 has resulted in the urgent need for an in-depth understanding of molecular functions of viral proteins and their interactions with the host proteome. Several individual omics studies have extended our knowledge of COVID-19 pathophysiology1-10. Integration of such datasets to obtain a holistic view of virus-host interactions and to define the pathogenic properties of SARS-CoV-2 is limited by the heterogeneity of the experimental systems. Here we report a concurrent multi-omics study of SARS-CoV-2 and SARS-CoV. Using state-of-the-art proteomics, we profiled the interactomes of both viruses, as well as their influence on the transcriptome, proteome, ubiquitinome and phosphoproteome of a lung-derived human cell line. Projecting these data onto the global network of cellular interactions revealed crosstalk between the perturbations taking place upon infection with SARS-CoV-2 and SARS-CoV at different levels and enabled identification of distinct and common molecular mechanisms of these closely related coronaviruses. The TGF-ß pathway, known for its involvement in tissue fibrosis, was specifically dysregulated by SARS-CoV-2 ORF8 and autophagy was specifically dysregulated by SARS-CoV-2 ORF3. The extensive dataset (available at https://covinet.innatelab.org ) highlights many hotspots that could be targeted by existing drugs and may be used to guide rational design of virus- and host-directed therapies, which we exemplify by identifying inhibitors of kinases and matrix metalloproteases with potent antiviral effects against SARS-CoV-2.


Subject(s)
COVID-19/metabolism , Host-Pathogen Interactions , Proteome/metabolism , Proteomics , SARS Virus/pathogenicity , SARS-CoV-2/pathogenicity , Severe Acute Respiratory Syndrome/metabolism , Animals , Antiviral Agents/pharmacology , Autophagy/drug effects , COVID-19/immunology , COVID-19/virology , Cell Line , Datasets as Topic , Drug Evaluation, Preclinical , Host-Pathogen Interactions/immunology , Humans , Matrix Metalloproteinase Inhibitors/pharmacology , Phosphorylation , Protein Interaction Maps , Protein Kinase Inhibitors/pharmacology , Protein Processing, Post-Translational , Proteome/chemistry , SARS Virus/immunology , SARS-CoV-2/immunology , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/virology , Transforming Growth Factor beta/metabolism , Ubiquitination , Viral Proteins/chemistry , Viral Proteins/metabolism , Viroporin Proteins/metabolism
18.
Methods Mol Biol ; 2203: 187-204, 2020.
Article in English | MEDLINE | ID: covidwho-729907

ABSTRACT

Biotin-based proximity labeling circumvents major pitfalls of classical biochemical approaches to identify protein-protein interactions. It consists of enzyme-catalyzed biotin tags ubiquitously apposed on proteins located in close proximity of the labeling enzyme, followed by affinity purification and identification of biotinylated proteins by mass spectrometry. Here we outline the methods by which the molecular microenvironment of the coronavirus replicase/transcriptase complex (RTC), i.e., proteins located within a close perimeter of the RTC, can be determined by different proximity labeling approaches using BirAR118G (BioID), TurboID, and APEX2. These factors represent a molecular signature of coronavirus RTCs and likely contribute to the viral life cycle, thereby constituting attractive targets for the development of antiviral intervention strategies.


Subject(s)
Coronavirus/pathogenicity , Enzymes/genetics , Host-Pathogen Interactions/physiology , Proteomics/methods , Viral Proteins/metabolism , Animals , Ascorbate Peroxidases/genetics , Biotinylation , Carbon-Nitrogen Ligases/genetics , Cell Line , Coronavirus/genetics , Enzymes/metabolism , Escherichia coli Proteins/genetics , Fluorescent Antibody Technique , Microorganisms, Genetically-Modified , Repressor Proteins/genetics , Viral Proteins/chemistry , Viral Proteins/genetics
19.
PLoS Biol ; 19(3): e3001158, 2021 03.
Article in English | MEDLINE | ID: covidwho-1156073

ABSTRACT

Since its emergence in December 2019, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread globally and become a major public health burden. Despite its close phylogenetic relationship to SARS-CoV, SARS-CoV-2 exhibits increased human-to-human transmission dynamics, likely due to efficient early replication in the upper respiratory epithelium of infected individuals. Since different temperatures encountered in the human upper and lower respiratory tract (33°C and 37°C, respectively) have been shown to affect the replication kinetics of several respiratory viruses, as well as host innate immune response dynamics, we investigated the impact of temperature on SARS-CoV-2 and SARS-CoV infection using the primary human airway epithelial cell culture model. SARS-CoV-2, in contrast to SARS-CoV, replicated to higher titers when infections were performed at 33°C rather than 37°C. Although both viruses were highly sensitive to type I and type III interferon pretreatment, a detailed time-resolved transcriptome analysis revealed temperature-dependent interferon and pro-inflammatory responses induced by SARS-CoV-2 that were inversely proportional to its replication efficiency at 33°C or 37°C. These data provide crucial insight on pivotal virus-host interaction dynamics and are in line with characteristic clinical features of SARS-CoV-2 and SARS-CoV, as well as their respective transmission efficiencies.


Subject(s)
Gene Expression Profiling/methods , Gene Expression Regulation, Viral/genetics , SARS Virus/genetics , SARS-CoV-2/genetics , Animals , Antiviral Agents/pharmacology , Cells, Cultured , Chlorocebus aethiops , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Epithelial Cells/virology , Gene Expression Regulation, Viral/drug effects , Host-Pathogen Interactions/drug effects , Host-Pathogen Interactions/genetics , Humans , Interferons/pharmacology , SARS Virus/drug effects , SARS Virus/physiology , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Species Specificity , Temperature , Vero Cells , Virus Replication/drug effects , Virus Replication/genetics
20.
Sci Immunol ; 6(57)2021 03 04.
Article in English | MEDLINE | ID: covidwho-1148101

ABSTRACT

CD8+ T cell immunity to SARS-CoV-2 has been implicated in COVID-19 severity and virus control. Here, we identified nonsynonymous mutations in MHC-I-restricted CD8+ T cell epitopes after deep sequencing of 747 SARS-CoV-2 virus isolates. Mutant peptides exhibited diminished or abrogated MHC-I binding in a cell-free in vitro assay. Reduced MHC-I binding of mutant peptides was associated with decreased proliferation, IFN-γ production and cytotoxic activity of CD8+ T cells isolated from HLA-matched COVID-19 patients. Single cell RNA sequencing of ex vivo expanded, tetramer-sorted CD8+ T cells from COVID-19 patients further revealed qualitative differences in the transcriptional response to mutant peptides. Our findings highlight the capacity of SARS-CoV-2 to subvert CD8+ T cell surveillance through point mutations in MHC-I-restricted viral epitopes.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19 , Epitopes, T-Lymphocyte , HLA-A Antigens/immunology , Immunity, Cellular , Mutation , SARS-CoV-2 , CD8-Positive T-Lymphocytes/pathology , COVID-19/genetics , COVID-19/immunology , COVID-19/pathology , Cell Proliferation , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/immunology , High-Throughput Nucleotide Sequencing , Humans , Interferon-gamma/immunology , Peptides/genetics , Peptides/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology
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