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1.
Viruses ; 12(7)2020 07 14.
Article in English | MEDLINE | ID: covidwho-649596

ABSTRACT

Next-generation sequencing (NGS) offers a powerful opportunity to identify low-abundance, intra-host viral sequence variants, yet the focus of many bioinformatic tools on consensus sequence construction has precluded a thorough analysis of intra-host diversity. To take full advantage of the resolution of NGS data, we developed HAplotype PHylodynamics PIPEline (HAPHPIPE), an open-source tool for the de novo and reference-based assembly of viral NGS data, with both consensus sequence assembly and a focus on the quantification of intra-host variation through haplotype reconstruction. We validate and compare the consensus sequence assembly methods of HAPHPIPE to those of two alternative software packages, HyDRA and Geneious, using simulated HIV and empirical HIV, HCV, and SARS-CoV-2 datasets. Our validation methods included read mapping, genetic distance, and genetic diversity metrics. In simulated NGS data, HAPHPIPE generated pol consensus sequences significantly closer to the true consensus sequence than those produced by HyDRA and Geneious and performed comparably to Geneious for HIV gp120 sequences. Furthermore, using empirical data from multiple viruses, we demonstrate that HAPHPIPE can analyze larger sequence datasets due to its greater computational speed. Therefore, we contend that HAPHPIPE provides a more user-friendly platform for users with and without bioinformatics experience to implement current best practices for viral NGS assembly than other currently available options.


Subject(s)
Computational Biology/methods , High-Throughput Nucleotide Sequencing/methods , Viruses/genetics , Betacoronavirus/genetics , Coronavirus Infections/virology , Genome, Viral , Genomics/methods , HIV/genetics , Haplotypes , Hepacivirus/genetics , Humans , Pandemics , Pneumonia, Viral/virology
2.
Euro Surveill ; 25(28)2020 07.
Article in English | MEDLINE | ID: covidwho-647504

ABSTRACT

BackgroundA novel coronavirus, SARS-CoV-2, which emerged at the end of 2019 and causes COVID-19, has resulted in worldwide human infections. While genetically distinct, SARS-CoV-1, the aetiological agent responsible for an outbreak of severe acute respiratory syndrome (SARS) in 2002-2003, utilises the same host cell receptor as SARS-CoV-2 for entry: angiotensin-converting enzyme 2 (ACE2). Parts of the SARS-CoV-1 spike glycoprotein (S protein), which interacts with ACE2, appear conserved in SARS-CoV-2.AimThe cross-reactivity with SARS-CoV-2 of monoclonal antibodies (mAbs) previously generated against the S protein of SARS-CoV-1 was assessed.MethodsThe SARS-CoV-2 S protein sequence was aligned to those of SARS-CoV-1, Middle East respiratory syndrome (MERS) and common-cold coronaviruses. Abilities of mAbs generated against SARS-CoV-1 S protein to bind SARS-CoV-2 or its S protein were tested with SARS-CoV-2 infected cells as well as cells expressing either the full length protein or a fragment of its S2 subunit. Quantitative ELISA was also performed to compare binding of mAbs to recombinant S protein.ResultsAn immunogenic domain in the S2 subunit of SARS-CoV-1 S protein is highly conserved in SARS-CoV-2 but not in MERS and human common-cold coronaviruses. Four murine mAbs raised against this immunogenic fragment could recognise SARS-CoV-2 S protein expressed in mammalian cell lines. In particular, mAb 1A9 was demonstrated to detect S protein in SARS-CoV-2-infected cells and is suitable for use in a sandwich ELISA format.ConclusionThe cross-reactive mAbs may serve as useful tools for SARS-CoV-2 research and for the development of diagnostic assays for COVID-19.


Subject(s)
Antibodies, Monoclonal/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , SARS Virus/immunology , Severe Acute Respiratory Syndrome/immunology , Spike Glycoprotein, Coronavirus/immunology , Amino Acid Sequence , Animals , Betacoronavirus/genetics , Blotting, Western , COS Cells , Chlorocebus aethiops , Conserved Sequence , Coronavirus Infections/genetics , Coronavirus Infections/virology , Cross Reactions/immunology , Enzyme-Linked Immunosorbent Assay/methods , Fluorescent Antibody Technique/methods , Genome, Viral , Mice , Pandemics , Peptidyl-Dipeptidase A/immunology , Plasmids , Pneumonia, Viral/genetics , Recombinant Proteins/immunology , SARS Virus/genetics , Sequence Alignment , Severe Acute Respiratory Syndrome/virology , Spike Glycoprotein, Coronavirus/genetics , Transfection , Vero Cells , Virus Integration
3.
Genome Med ; 12(1): 57, 2020 06 30.
Article in English | MEDLINE | ID: covidwho-618232

ABSTRACT

BACKGROUND: COVID-19 (coronavirus disease 2019) has caused a major epidemic worldwide; however, much is yet to be known about the epidemiology and evolution of the virus partly due to the scarcity of full-length SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) genomes reported. One reason is that the challenges underneath sequencing SARS-CoV-2 directly from clinical samples have not been completely tackled, i.e., sequencing samples with low viral load often results in insufficient viral reads for analyses. METHODS: We applied a novel multiplex PCR amplicon (amplicon)-based and hybrid capture (capture)-based sequencing, as well as ultra-high-throughput metatranscriptomic (meta) sequencing in retrieving complete genomes, inter-individual and intra-individual variations of SARS-CoV-2 from serials dilutions of a cultured isolate, and eight clinical samples covering a range of sample types and viral loads. We also examined and compared the sensitivity, accuracy, and other characteristics of these approaches in a comprehensive manner. RESULTS: We demonstrated that both amplicon and capture methods efficiently enriched SARS-CoV-2 content from clinical samples, while the enrichment efficiency of amplicon outran that of capture in more challenging samples. We found that capture was not as accurate as meta and amplicon in identifying between-sample variations, whereas amplicon method was not as accurate as the other two in investigating within-sample variations, suggesting amplicon sequencing was not suitable for studying virus-host interactions and viral transmission that heavily rely on intra-host dynamics. We illustrated that meta uncovered rich genetic information in the clinical samples besides SARS-CoV-2, providing references for clinical diagnostics and therapeutics. Taken all factors above and cost-effectiveness into consideration, we proposed guidance for how to choose sequencing strategy for SARS-CoV-2 under different situations. CONCLUSIONS: This is, to the best of our knowledge, the first work systematically investigating inter- and intra-individual variations of SARS-CoV-2 using amplicon- and capture-based whole-genome sequencing, as well as the first comparative study among multiple approaches. Our work offers practical solutions for genome sequencing and analyses of SARS-CoV-2 and other emerging viruses.


Subject(s)
Betacoronavirus/genetics , Genome, Viral/genetics , High-Throughput Nucleotide Sequencing/methods , Whole Genome Sequencing/methods , Coronavirus Infections , Genetic Variation/genetics , Host-Pathogen Interactions/genetics , Humans , Multiplex Polymerase Chain Reaction/methods , Pandemics , Pneumonia, Viral , RNA, Viral/genetics
4.
J Virol ; 94(15)2020 07 16.
Article in English | MEDLINE | ID: covidwho-762192

ABSTRACT

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe acute respiratory disease in humans. MERS-CoV strains from early epidemic clade A and contemporary epidemic clade B have not been phenotypically characterized to compare their abilities to infect cells and mice. We isolated the clade B MERS-CoV ChinaGD01 strain from a patient infected during the South Korean MERS outbreak in 2015 and compared the phylogenetics and pathogenicity of MERS-CoV EMC/2012 (clade A) and ChinaGD01 (clade B) in vitro and in vivo Genome alignment analysis showed that most clade-specific mutations occurred in the orf1ab gene, including mutations that were predicted to be potential glycosylation sites. Minor differences in viral growth but no significant differences in plaque size or sensitivity to beta interferon (IFN-ß) were detected between these two viruses in vitro ChinaGD01 virus infection induced more weight loss and inflammatory cytokine production in human DPP4-transduced mice. Viral titers were higher in the lungs of ChinaGD01-infected mice than with EMC/2012 infection. Decreased virus-specific CD4+ and CD8+ T cell numbers were detected in the lungs of ChinaGD01-infected mice. In conclusion, MERS-CoV evolution induced changes to reshape its pathogenicity and virulence in vitro and in vivo and to evade adaptive immune response to hinder viral clearance.IMPORTANCE MERS-CoV is an important emerging pathogen and causes severe respiratory infection in humans. MERS-CoV strains from early epidemic clade A and contemporary epidemic clade B have not been phenotypically characterized to compare their abilities to infect cells and mice. In this study, we showed that a clade B virus ChinaGD01 strain caused more severe disease in mice, with delayed viral clearance, increased inflammatory cytokines, and decreased antiviral T cell responses, than the early clade A virus EMC/2012. Given the differences in pathogenicity of different clades of MERS-CoV, periodic assessment of currently circulating MERS-CoV is needed to monitor potential severity of zoonotic disease.


Subject(s)
Coronavirus Infections/virology , Genotype , Host-Pathogen Interactions , Middle East Respiratory Syndrome Coronavirus/physiology , Adult , Animals , Disease Models, Animal , Genome, Viral , Host-Pathogen Interactions/immunology , Humans , Interferon Type I/pharmacology , Male , Mice , Middle East Respiratory Syndrome Coronavirus/classification , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Phylogeny , RNA, Viral , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Virulence , Virus Replication/drug effects , Virus Replication/genetics , Whole Genome Sequencing
5.
Methods Mol Biol ; 2203: 67-74, 2020.
Article in English | MEDLINE | ID: covidwho-761347

ABSTRACT

This chapter reports the high-throughput sequencing protocol for sequencing Coronaviruses and other positive strand viruses to produce a dataset of significant depth of coverage. The protocol describes sequencing of infectious bronchitis virus propagated in embryonated eggs and harvested in the allantoic fluid. The protocol is composed of three main steps-enrichment of the allantoic fluid using ultracentrifugation, extraction of total RNA from allantoic fluid, and library preparation from total RNA to DNA sequencing libraries. The workflow will be suitable for all coronaviruses using high-throughput sequencing platforms.


Subject(s)
Coronavirus/genetics , Whole Genome Sequencing/methods , Animals , Chorioallantoic Membrane/virology , Genome, Viral , High-Throughput Nucleotide Sequencing/methods , Infectious bronchitis virus/genetics , Infectious bronchitis virus/isolation & purification , Workflow
6.
Sci Rep ; 10(1): 14179, 2020 08 25.
Article in English | MEDLINE | ID: covidwho-741695

ABSTRACT

A novel coronavirus (SARS-CoV-2) emerged from China in late 2019 and rapidly spread across the globe, infecting millions of people and generating societal disruption on a level not seen since the 1918 influenza pandemic. A safe and effective vaccine is desperately needed to prevent the continued spread of SARS-CoV-2; yet, rational vaccine design efforts are currently hampered by the lack of knowledge regarding viral epitopes targeted during an immune response, and the need for more in-depth knowledge on betacoronavirus immunology. To that end, we developed a computational workflow using a series of open-source algorithms and webtools to analyze the proteome of SARS-CoV-2 and identify putative T cell and B cell epitopes. Utilizing a set of stringent selection criteria to filter peptide epitopes, we identified 41 T cell epitopes (5 HLA class I, 36 HLA class II) and 6 B cell epitopes that could serve as promising targets for peptide-based vaccine development against this emerging global pathogen. To our knowledge, this is the first study to comprehensively analyze all 10 (structural, non-structural and accessory) proteins from SARS-CoV-2 using predictive algorithms to identify potential targets for vaccine development.


Subject(s)
Betacoronavirus/immunology , Computational Biology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Host-Pathogen Interactions/immunology , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Viral Proteins/immunology , Amino Acid Sequence , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , Betacoronavirus/classification , Betacoronavirus/genetics , Betacoronavirus/metabolism , Computational Biology/methods , Coronavirus Infections/metabolism , Epitopes, B-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/chemistry , Genome, Viral , Genomics/methods , Humans , Models, Molecular , Pandemics , Peptides/chemistry , Peptides/immunology , Phylogeny , Pneumonia, Viral/metabolism , Structure-Activity Relationship , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Vaccines, Subunit/immunology , Viral Proteins/chemistry , Viral Vaccines/immunology
7.
J Fr Ophtalmol ; 43(7): 642-652, 2020 Sep.
Article in French | MEDLINE | ID: covidwho-741338

ABSTRACT

The COVID-19 pandemic has dramatically changed our daily lives as ophthalmologists. This general review firstly provides a better understanding of the virus responsible for the pandemic: the SARS-CoV-2, and the clinical manifestations of the COVID-19 disease. The second part is detailing the pathophysiology, clinical signs and challenges of ocular involvement, which seems rare and not functionally severe, but which may be a potential source of contamination. Finally, we discuss the preventive measures that need to be implemented in our daily practice to avoid any viral dissemination.


Subject(s)
Betacoronavirus , Coronavirus Infections/complications , Eye Infections, Viral/virology , Pneumonia, Viral/complications , Betacoronavirus/genetics , Betacoronavirus/ultrastructure , Coronavirus Infections/epidemiology , Coronavirus Infections/physiopathology , Coronavirus Infections/prevention & control , Diagnostic Techniques, Ophthalmological , Eye/virology , Eye Infections, Viral/physiopathology , Eye Infections, Viral/prevention & control , Genome, Viral , Humans , Microscopy, Electron , Pandemics/prevention & control , Pneumonia, Viral/epidemiology , Pneumonia, Viral/physiopathology , Pneumonia, Viral/prevention & control , Virus Integration
8.
J Virol ; 94(17)2020 08 17.
Article in English | MEDLINE | ID: covidwho-740271

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus first identified in December 2019. Notable features that make SARS-CoV-2 distinct from most other previously identified betacoronaviruses include a receptor binding domain and a unique insertion of 12 nucleotides or 4 amino acids (PRRA) at the S1/S2 boundary. In this study, we identified two deletion variants of SARS-CoV-2 that either directly affect the polybasic cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN). These deletions were verified by multiple sequencing methods. In vitro results showed that the deletion of NSPRRAR likely does not affect virus replication in Vero and Vero-E6 cells; however, the deletion of QTQTN may restrict late-phase viral replication. The deletion of QTQTN was detected in 3 of 68 clinical samples and 12 of 24 in vitro-isolated viruses, while the deletion of NSPRRAR was identified in 3 in vitro-isolated viruses. Our data indicate that (i) there may be distinct selection pressures on SARS-CoV-2 replication or infection in vitro and in vivo; (ii) an efficient mechanism for deleting this region from the viral genome may exist, given that the deletion variant is commonly detected after two rounds of cell passage; and (iii) the PRRA insertion, which is unique to SARS-CoV-2, is not fixed during virus replication in vitro These findings provide information to aid further investigation of SARS-CoV-2 infection mechanisms and a better understanding of the NSPRRAR deletion variant observed here.IMPORTANCE The spike protein determines the infectivity and host range of coronaviruses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has two unique features in its spike protein, the receptor binding domain and an insertion of 12 nucleotides at the S1/S2 boundary resulting in a furin-like cleavage site. Here, we identified two deletion variants of SARS-CoV-2 that either directly affect the furin-like cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN), and we investigated these deletions in cell isolates and clinical samples. The absence of the polybasic cleavage site in SARS-CoV-2 did not affect virus replication in Vero or Vero-E6 cells. Our data indicate the PRRAR sequence and the flanking QTQTN sequence are not fixed in vitro; thus, there appears to be distinct selection pressures on SARS-CoV-2 sequences in vitro and in vivo Further investigation of the mechanism of generating these deletion variants and their infectivity in different animal models would improve our understanding of the origin and evolution of this virus.


Subject(s)
Betacoronavirus/genetics , Betacoronavirus/metabolism , Sequence Deletion , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/isolation & purification , Amino Acid Sequence , Animals , Base Sequence , Cell Line , Chlorocebus aethiops , Coronavirus Infections/virology , Furin/metabolism , Genome, Viral , Host Specificity , Kinetics , Models, Molecular , Pandemics , Pneumonia, Viral/virology , Protein Conformation , Sequence Analysis , Spike Glycoprotein, Coronavirus/chemistry , Vero Cells , Virus Replication
9.
J Transl Med ; 18(1): 329, 2020 08 31.
Article in English | MEDLINE | ID: covidwho-736398

ABSTRACT

BACKGROUND: The new Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which was first detected in Wuhan (China) in December of 2019 is responsible for the current global pandemic. Phylogenetic analysis revealed that it is similar to other betacoronaviruses, such as SARS-CoV and Middle-Eastern Respiratory Syndrome, MERS-CoV. Its genome is ∼ 30 kb in length and contains two large overlapping polyproteins, ORF1a and ORF1ab that encode for several structural and non-structural proteins. The non-structural protein 1 (nsp1) is arguably the most important pathogenic determinant, and previous studies on SARS-CoV indicate that it is both involved in viral replication and hampering the innate immune system response. Detailed experiments of site-specific mutagenesis and in vitro reconstitution studies determined that the mechanisms of action are mediated by (a) the presence of specific amino acid residues of nsp1 and (b) the interaction between the protein and the host's small ribosomal unit. In fact, substitution of certain amino acids resulted in reduction of its negative effects. METHODS: A total of 17,928 genome sequences were obtained from the GISAID database (December 2019 to July 2020) from patients infected by SARS-CoV-2 from different areas around the world. Genomes alignment was performed using MAFFT (REFF) and the nsp1 genomic regions were identified using BioEdit and verified using BLAST. Nsp1 protein of SARS-CoV-2 with and without deletion have been subsequently modelled using I-TASSER. RESULTS: We identified SARS-CoV-2 genome sequences, from several Countries, carrying a previously unknown deletion of 9 nucleotides in position 686-694, corresponding to the AA position 241-243 (KSF). This deletion was found in different geographical areas. Structural prediction modelling suggests an effect on the C-terminal tail structure. CONCLUSIONS: Modelling analysis of a newly identified deletion of 3 amino acids (KSF) of SARS-CoV-2 nsp1 suggests that this deletion could affect the structure of the C-terminal region of the protein, important for regulation of viral replication and negative effect on host's gene expression. In addition, substitution of the two amino acids (KS) from nsp1 of SARS-CoV was previously reported to revert loss of interferon-alpha expression. The deletion that we describe indicates that SARS-CoV-2 is undergoing profound genomic changes. It is important to: (i) confirm the spreading of this particular viral strain, and potentially of strains with other deletions in the nsp1 protein, both in the population of asymptomatic and pauci-symptomatic subjects, and (ii) correlate these changes in nsp1 with potential decreased viral pathogenicity.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Pneumonia, Viral/virology , Sequence Deletion , Viral Nonstructural Proteins/genetics , Amino Acid Sequence , Base Sequence , Betacoronavirus/pathogenicity , Communicable Diseases, Emerging/virology , Coronavirus Infections/epidemiology , Gene Frequency , Genome, Viral , Geography , Humans , Lysine/genetics , Models, Molecular , Pandemics/statistics & numerical data , Phenylalanine/genetics , Pneumonia, Viral/epidemiology , Protein Domains/genetics , Serine/genetics , Viral Nonstructural Proteins/chemistry , Virulence/genetics , Virus Replication/genetics
10.
J Virol ; 94(12)2020 06 01.
Article in English | MEDLINE | ID: covidwho-736044

ABSTRACT

The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that recently emerged in China is thought to have a bat origin, as its closest known relative (BatCoV RaTG13) was described previously in horseshoe bats. We analyzed the selective events that accompanied the divergence of SARS-CoV-2 from BatCoV RaTG13. To this end, we applied a population genetics-phylogenetics approach, which leverages within-population variation and divergence from an outgroup. Results indicated that most sites in the viral open reading frames (ORFs) evolved under conditions of strong to moderate purifying selection. The most highly constrained sequences corresponded to some nonstructural proteins (nsps) and to the M protein. Conversely, nsp1 and accessory ORFs, particularly ORF8, had a nonnegligible proportion of codons evolving under conditions of very weak purifying selection or close to selective neutrality. Overall, limited evidence of positive selection was detected. The 6 bona fide positively selected sites were located in the N protein, in ORF8, and in nsp1. A signal of positive selection was also detected in the receptor-binding motif (RBM) of the spike protein but most likely resulted from a recombination event that involved the BatCoV RaTG13 sequence. In line with previous data, we suggest that the common ancestor of SARS-CoV-2 and BatCoV RaTG13 encoded/encodes an RBM similar to that observed in SARS-CoV-2 itself and in some pangolin viruses. It is presently unknown whether the common ancestor still exists and, if so, which animals it infects. Our data, however, indicate that divergence of SARS-CoV-2 from BatCoV RaTG13 was accompanied by limited episodes of positive selection, suggesting that the common ancestor of the two viruses was poised for human infection.IMPORTANCE Coronaviruses are dangerous zoonotic pathogens; in the last 2 decades, three coronaviruses have crossed the species barrier and caused human epidemics. One of these is the recently emerged SARS-CoV-2. We investigated how, since its divergence from a closely related bat virus, natural selection shaped the genome of SARS-CoV-2. We found that distinct coding regions in the SARS-CoV-2 genome evolved under conditions of different degrees of constraint and are consequently more or less prone to tolerate amino acid substitutions. In practical terms, the level of constraint provides indications about which proteins/protein regions are better suited as possible targets for the development of antivirals or vaccines. We also detected limited signals of positive selection in three viral ORFs. However, we warn that, in the absence of knowledge about the chain of events that determined the human spillover, these signals should not be necessarily interpreted as evidence of an adaptation to our species.


Subject(s)
Betacoronavirus/genetics , Evolution, Molecular , Selection, Genetic , Amino Acid Sequence , Animals , Betacoronavirus/classification , Chiroptera/virology , Coronavirus Infections/virology , Genome, Viral/genetics , Humans , Models, Molecular , Open Reading Frames/genetics , Pandemics , Phylogeny , Pneumonia, Viral/virology , Viral Proteins/chemistry , Viral Proteins/genetics
11.
J Chin Med Assoc ; 83(8): 712-718, 2020 08.
Article in English | MEDLINE | ID: covidwho-733326

ABSTRACT

Recently, the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was quickly identified as the causal pathogen leading to the outbreak of SARS-like illness all over the world. As the SARS-CoV-2 infection pandemic proceeds, many efforts are being dedicated to the development of diverse treatment strategies. Increasing evidence showed potential therapeutic agents directly acting against SARS-CoV-2 virus, such as interferon, RNA-dependent RNA polymerase inhibitors, protease inhibitors, viral entry blockers, neuraminidase inhibitor, vaccine, antibody agent targeting the SARS-CoV-2 RNA genome, natural killer cells, and nucleocytoplasmic trafficking inhibitor. To date, several direct anti-SARS-CoV-2 agents have demonstrated promising in vitro and clinical efficacy. This article reviews the current and future development of direct acting agents against SARS-CoV-2.


Subject(s)
Antiviral Agents/therapeutic use , Betacoronavirus , Coronavirus Infections/drug therapy , Drug Development , Pneumonia, Viral/drug therapy , Active Transport, Cell Nucleus/drug effects , Antibodies, Monoclonal/therapeutic use , Betacoronavirus/genetics , Genome, Viral , Humans , Killer Cells, Natural/immunology , Pandemics
12.
Virol J ; 17(1): 131, 2020 08 27.
Article in English | MEDLINE | ID: covidwho-733041

ABSTRACT

BACKGROUND: The Covid19 infection is caused by the SARS-CoV-2 virus, a novel member of the coronavirus (CoV) family. CoV genomes code for a ORF1a / ORF1ab polyprotein and four structural proteins widely studied as major drug targets. The genomes also contain a variable number of open reading frames (ORFs) coding for accessory proteins that are not essential for virus replication, but appear to have a role in pathogenesis. The accessory proteins have been less well characterized and are difficult to predict by classical bioinformatics methods. METHODS: We propose a computational tool GOFIX to characterize potential ORFs in virus genomes. In particular, ORF coding potential is estimated by searching for enrichment in motifs of the X circular code, that is known to be over-represented in the reading frames of viral genes. RESULTS: We applied GOFIX to study the SARS-CoV-2 and related genomes including SARS-CoV and SARS-like viruses from bat, civet and pangolin hosts, focusing on the accessory proteins. Our analysis provides evidence supporting the presence of overlapping ORFs 7b, 9b and 9c in all the genomes and thus helps to resolve some differences in current genome annotations. In contrast, we predict that ORF3b is not functional in all genomes. Novel putative ORFs were also predicted, including a truncated form of the ORF10 previously identified in SARS-CoV-2 and a little known ORF overlapping the Spike protein in Civet-CoV and SARS-CoV. CONCLUSIONS: Our findings contribute to characterizing sequence properties of accessory genes of SARS coronaviruses, and especially the newly acquired genes making use of overlapping reading frames.


Subject(s)
Betacoronavirus/genetics , Genome, Viral , Open Reading Frames , SARS Virus/genetics , Viral Regulatory and Accessory Proteins/genetics , Animals , Codon , Computational Biology , Evolution, Molecular , Genes, Viral , Humans , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Viral Matrix Proteins/genetics , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Regulatory and Accessory Proteins/chemistry
13.
PLoS Pathog ; 16(8): e1008705, 2020 08.
Article in English | MEDLINE | ID: covidwho-732988

ABSTRACT

The recent outbreak of human infections caused by SARS-CoV-2, the third zoonotic coronavirus has raised great public health concern globally. Rapid and accurate diagnosis of this novel pathogen posts great challenges not only clinically but also technologically. Metagenomic next-generation sequencing (mNGS) and reverse-transcription PCR (RT-PCR) have been the most commonly used molecular methodologies. However, each has their own limitations. In this study, we developed an isothermal, CRISPR-based diagnostic for COVID-19 with near single-copy sensitivity. The diagnostic performances of all three technology platforms were also compared. Our study aimed to provide more insights into the molecular detection of SARS-CoV-2, and also to present a novel diagnostic option for this new emerging virus.


Subject(s)
Betacoronavirus/genetics , CRISPR-Cas Systems/genetics , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus Infections/genetics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/genetics , Bacteria/genetics , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , Genes, Viral/genetics , Genome, Viral/genetics , High-Throughput Nucleotide Sequencing/methods , Humans , Molecular Diagnostic Techniques/economics , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/economics , Nucleic Acid Amplification Techniques/methods , Pandemics , Reverse Transcriptase Polymerase Chain Reaction/methods , Sensitivity and Specificity
14.
Genes (Basel) ; 11(9)2020 08 26.
Article in English | MEDLINE | ID: covidwho-730522

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an RNA virus, is responsible for the coronavirus disease 2019 (COVID-19) pandemic of 2020. Experimental evidence suggests that microRNA can mediate an intracellular defence mechanism against some RNA viruses. The purpose of this study was to identify microRNA with predicted binding sites in the SARS-CoV-2 genome, compare these to their microRNA expression profiles in lung epithelial tissue and make inference towards possible roles for microRNA in mitigating coronavirus infection. We hypothesize that high expression of specific coronavirus-targeting microRNA in lung epithelia may protect against infection and viral propagation, conversely, low expression may confer susceptibility to infection. We have identified 128 human microRNA with potential to target the SARS-CoV-2 genome, most of which have very low expression in lung epithelia. Six of these 128 microRNA are differentially expressed upon in vitro infection of SARS-CoV-2. Additionally, 28 microRNA also target the SARS-CoV genome while 23 microRNA target the MERS-CoV genome. We also found that a number of microRNA are commonly identified in two other studies. Further research into identifying bona fide coronavirus targeting microRNA will be useful in understanding the importance of microRNA as a cellular defence mechanism against pathogenic coronavirus infections.


Subject(s)
Alveolar Epithelial Cells/virology , Betacoronavirus/genetics , MicroRNAs/genetics , Alveolar Epithelial Cells/immunology , Betacoronavirus/pathogenicity , Cell Line, Tumor , Genome, Viral , Humans , MicroRNAs/metabolism , Nucleotide Motifs , Sequence Analysis, RNA
15.
Cell Physiol Biochem ; 54(4): 767-790, 2020 Aug 25.
Article in English | MEDLINE | ID: covidwho-729851

ABSTRACT

The pandemic of the severe acute respiratory syndrome coronavirus (SARS-CoV)-2 at the end of 2019 marked the third outbreak of a highly pathogenic coronavirus affecting the human population in the past twenty years. Cross-species zoonotic transmission of SARS-CoV-2 has caused severe pathogenicity and led to more than 655,000 fatalities worldwide until July 28, 2020. Outbursts of this virus underlined the importance of controlling infectious pathogens across international frontiers. Unfortunately, there is currently no clinically approved antiviral drug or vaccine against SARS-CoV-2, although several broad-spectrum antiviral drugs targeting multiple RNA viruses have shown a positive response and improved recovery in patients. In this review, we compile our current knowledge of the emergence, transmission, and pathogenesis of SARS-CoV-2 and explore several features of SARS-CoV-2. We emphasize the current therapeutic approaches used to treat infected patients. We also highlight the results of in vitro and in vivo data from several studies, which have broadened our knowledge of potential drug candidates for the successful treatment of patients infected with and discuss possible virus and host-based treatment options against SARS-CoV-2.


Subject(s)
Betacoronavirus , Coronavirus Infections , Pandemics , Pneumonia, Viral , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Betacoronavirus/genetics , Betacoronavirus/physiology , Coronaviridae/pathogenicity , Coronaviridae Infections/epidemiology , Coronaviridae Infections/virology , Coronavirus Infections/drug therapy , Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Coronavirus Infections/therapy , Coronavirus Infections/transmission , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/prevention & control , Cytokines/antagonists & inhibitors , Drug Delivery Systems , Endocytosis/drug effects , Forecasting , Genome, Viral , Global Health , Humans , Immunity, Herd , Immunization, Passive , Pandemics/prevention & control , Peptide Hydrolases/pharmacology , Peptide Hydrolases/therapeutic use , Pneumonia, Viral/drug therapy , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , RNA, Viral/genetics , Receptors, Virus/antagonists & inhibitors , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/metabolism , Viral Vaccines , Virus Internalization/drug effects , Virus Replication/drug effects , Zoonoses
16.
Genes (Basel) ; 11(8)2020 08 17.
Article in English | MEDLINE | ID: covidwho-725327

ABSTRACT

The COVID-19 pandemic has spread very fast around the world. A few days after the first detected case in South Africa, an infection started in a large hospital outbreak in Durban, KwaZulu-Natal (KZN). Phylogenetic analysis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes can be used to trace the path of transmission within a hospital. It can also identify the source of the outbreak and provide lessons to improve infection prevention and control strategies. This manuscript outlines the obstacles encountered in order to genotype SARS-CoV-2 in near-real time during an urgent outbreak investigation. This included problems with the length of the original genotyping protocol, unavailability of reagents, and sample degradation and storage. Despite this, three different library preparation methods for Illumina sequencing were set up, and the hands-on library preparation time was decreased from twelve to three hours, which enabled the outbreak investigation to be completed in just a few weeks. Furthermore, the new protocols increased the success rate of sequencing whole viral genomes. A simple bioinformatics workflow for the assembly of high-quality genomes in near-real time was also fine-tuned. In order to allow other laboratories to learn from our experience, all of the library preparation and bioinformatics protocols are publicly available at protocols.io and distributed to other laboratories of the Network for Genomics Surveillance in South Africa (NGS-SA) consortium.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/diagnosis , Genome, Viral , High-Throughput Nucleotide Sequencing/methods , Molecular Diagnostic Techniques/methods , Pneumonia, Viral/diagnosis , Whole Genome Sequencing/methods , Betacoronavirus/pathogenicity , Coronavirus Infections/virology , High-Throughput Nucleotide Sequencing/standards , Humans , Molecular Diagnostic Techniques/standards , Pandemics , Pneumonia, Viral/virology , Reproducibility of Results , Sensitivity and Specificity , Whole Genome Sequencing/standards
17.
Sci Rep ; 10(1): 14004, 2020 08 19.
Article in English | MEDLINE | ID: covidwho-724698

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a novel evolutionary divergent RNA virus, is responsible for the present devastating COVID-19 pandemic. To explore the genomic signatures, we comprehensively analyzed 2,492 complete and/or near-complete genome sequences of SARS-CoV-2 strains reported from across the globe to the GISAID database up to 30 March 2020. Genome-wide annotations revealed 1,516 nucleotide-level variations at different positions throughout the entire genome of SARS-CoV-2. Moreover, nucleotide (nt) deletion analysis found twelve deletion sites throughout the genome other than previously reported deletions at coding sequence of the ORF8 (open reading frame), spike, and ORF7a proteins, specifically in polyprotein ORF1ab (n = 9), ORF10 (n = 1), and 3´-UTR (n = 2). Evidence from the systematic gene-level mutational and protein profile analyses revealed a large number of amino acid (aa) substitutions (n = 744), demonstrating the viral proteins heterogeneous. Notably, residues of receptor-binding domain (RBD) showing crucial interactions with angiotensin-converting enzyme 2 (ACE2) and cross-reacting neutralizing antibody were found to be conserved among the analyzed virus strains, except for replacement of lysine with arginine at 378th position of the cryptic epitope of a Shanghai isolate, hCoV-19/Shanghai/SH0007/2020 (EPI_ISL_416320). Furthermore, our results of the preliminary epidemiological data on SARS-CoV-2 infections revealed that frequency of aa mutations were relatively higher in the SARS-CoV-2 genome sequences of Europe (43.07%) followed by Asia (38.09%), and North America (29.64%) while case fatality rates remained higher in the European temperate countries, such as Italy, Spain, Netherlands, France, England and Belgium. Thus, the present method of genome annotation employed at this early pandemic stage could be a promising tool for monitoring and tracking the continuously evolving pandemic situation, the associated genetic variants, and their implications for the development of effective control and prophylaxis strategies.


Subject(s)
Betacoronavirus/classification , Betacoronavirus/genetics , Coronavirus Infections/epidemiology , Genetic Heterogeneity , Genome, Viral/genetics , Genome-Wide Association Study/methods , Global Health , Pneumonia, Viral/epidemiology , Amino Acid Sequence/genetics , Antibodies, Neutralizing/immunology , Base Pair Mismatch , Base Sequence/genetics , Climate , Coronavirus Infections/virology , Humans , Open Reading Frames/genetics , Pandemics , Peptidyl-Dipeptidase A/metabolism , Phylogeny , Pneumonia, Viral/virology , Protein Domains/genetics , Protein Domains/immunology , Sequence Deletion , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
18.
Sci Rep ; 10(1): 14031, 2020 08 20.
Article in English | MEDLINE | ID: covidwho-724696

ABSTRACT

The COVID-19 pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), was declared on March 11, 2020 by the World Health Organization. As of the 31st of May, 2020, there have been more than 6 million COVID-19 cases diagnosed worldwide and over 370,000 deaths, according to Johns Hopkins. Thousands of SARS-CoV-2 strains have been sequenced to date, providing a valuable opportunity to investigate the evolution of the virus on a global scale. We performed a phylogenetic analysis of over 1,225 SARS-CoV-2 genomes spanning from late December 2019 to mid-March 2020. We identified a missense mutation, D614G, in the spike protein of SARS-CoV-2, which has emerged as a predominant clade in Europe (954 of 1,449 (66%) sequences) and is spreading worldwide (1,237 of 2,795 (44%) sequences). Molecular dating analysis estimated the emergence of this clade around mid-to-late January (10-25 January) 2020. We also applied structural bioinformatics to assess the potential impact of D614G on the virulence and epidemiology of SARS-CoV-2. In silico analyses on the spike protein structure suggests that the mutation is most likely neutral to protein function as it relates to its interaction with the human ACE2 receptor. The lack of clinical metadata available prevented our investigation of association between viral clade and disease severity phenotype. Future work that can leverage clinical outcome data with both viral and human genomic diversity is needed to monitor the pandemic.


Subject(s)
Betacoronavirus/chemistry , Coronavirus Infections/epidemiology , Evolution, Molecular , Pneumonia, Viral/epidemiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Base Sequence , Betacoronavirus/pathogenicity , Child , Child, Preschool , Computer Simulation , Coronavirus Infections/virology , Female , Genome, Viral/genetics , Humans , Infant , Male , Middle Aged , Mutation, Missense , Pandemics , Peptidyl-Dipeptidase A/metabolism , Phylogeny , Pneumonia, Viral/virology , Protein Conformation , Spike Glycoprotein, Coronavirus/metabolism , Virulence/genetics , Young Adult
19.
Front Immunol ; 11: 1664, 2020.
Article in English | MEDLINE | ID: covidwho-724205

ABSTRACT

The rapidly spreading, highly contagious and pathogenic SARS-coronavirus 2 (SARS-CoV-2) associated Coronavirus Disease 2019 (COVID-19) has been declared as a pandemic by the World Health Organization (WHO). The novel 2019 SARS-CoV-2 enters the host cell by binding of the viral surface spike glycoprotein (S-protein) to cellular angiotensin converting enzyme 2 (ACE2) receptor. The virus specific molecular interaction with the host cell represents a promising therapeutic target for identifying SARS-CoV-2 antiviral drugs. The repurposing of drugs can provide a rapid and potential cure toward exponentially expanding COVID-19. Thereto, high throughput virtual screening approach was used to investigate FDA approved LOPAC library drugs against both the receptor binding domain of spike protein (S-RBD) and ACE2 host cell receptor. Primary screening identified a few promising molecules for both the targets, which were further analyzed in details by their binding energy, binding modes through molecular docking, dynamics and simulations. Evidently, GR 127935 hydrochloride hydrate, GNF-5, RS504393, TNP, and eptifibatide acetate were found binding to virus binding motifs of ACE2 receptor. Additionally, KT203, BMS195614, KT185, RS504393, and GSK1838705A were identified to bind at the receptor binding site on the viral S-protein. These identified molecules may effectively assist in controlling the rapid spread of SARS-CoV-2 by not only potentially inhibiting the virus at entry step but are also hypothesized to act as anti-inflammatory agents, which could impart relief in lung inflammation. Timely identification and determination of an effective drug to combat and tranquilize the COVID-19 global crisis is the utmost need of hour. Further, prompt in vivo testing to validate the anti-SARS-CoV-2 inhibition efficiency by these molecules could save lives is justified.


Subject(s)
Betacoronavirus/physiology , Computer Simulation , Coronavirus Infections/drug therapy , Drug Repositioning/methods , Pneumonia, Viral/drug therapy , User-Computer Interface , Virus Internalization/drug effects , Anti-Inflammatory Agents/therapeutic use , Binding Sites , Coronavirus Infections/virology , Genome, Viral/genetics , Humans , Models, Genetic , Molecular Docking Simulation , Molecular Dynamics Simulation , Pandemics , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Protein Binding , Protein Domains , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/chemistry , Virus Attachment
20.
Genes (Basel) ; 11(8)2020 08 12.
Article in English | MEDLINE | ID: covidwho-721491

ABSTRACT

Deep knowledge of the genetic features of SARS-CoV-2 is essential to track the ongoing pandemic through different geographical areas and to design and develop early diagnostic procedures, therapeutic strategies, public health interventions, and vaccines. We describe protocols and first results of the Ion AmpliSeq™ SARS-CoV-2 Research Panel by a massively parallel sequencing (MPS) assay. The panel allows for targeted sequencing by overlapping amplicons, thereby providing specific, accurate, and high throughput analysis. A modified reverse transcription reaction, which consists of the use of a SARS-CoV-2 specific primers pool from the Ion AmpliSeq SARS-CoV-2 Research Panel, was assessed in order to promote viral RNA specific reverse transcription. The aim of this study was to evaluate the effectiveness of the Ion AmpliSeq™ SARS-CoV-2 Research Panel in sequencing the entire viral genome in different samples. SARS-CoV-2 sequence data were obtained from ten viral isolates and one nasopharyngeal swab from different patients. The ten isolate samples amplified with 12 PCR cycles displayed high mean depth values compared to those of the two isolates amplified with 20 PCR cycles. High mean depth values were also obtained for the nasopharyngeal swab processed by use of a target-specific reverse transcription. The relative depth of coverage (rDoC) analysis showed that when 12 PCR cycles were used, all target regions were amplified with high sequencing coverage, while in libraries amplified at 20 cycles, a poor uniformity of amplification, with absent or low coverage of many target regions, was observed. Our results show that the Ion AmpliSeq SARS-CoV-2 Research Panel can achieve rapid and high throughput SARS-CoV-2 whole genome sequencing from 10 ng of DNA-free viral RNA from isolates and from 1 ng of DNA-free viral RNA from a nasopharyngeal swab using 12 PCR cycles for library amplification. The modified RT-PCR protocol yielded superior results on the nasopharyngeal swab compared to the reverse transcription reaction set up according to the manufacturer's instructions.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Pneumonia, Viral/virology , Polymerase Chain Reaction/methods , Whole Genome Sequencing/methods , Adult , Aged , Aged, 80 and over , Animals , Betacoronavirus/pathogenicity , Chlorocebus aethiops , DNA Primers/standards , Female , Genome, Viral , Humans , Male , Middle Aged , Pandemics , Polymerase Chain Reaction/standards , Vero Cells , Whole Genome Sequencing/standards
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