Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 317
Filter
1.
Biomolecules ; 12(11)2022 Nov 12.
Article in English | MEDLINE | ID: covidwho-2109925

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently widespread throughout the world, accompanied by a rising number of people infected and breakthrough infection of variants, which make the virus highly transmissible and replicable. A comprehensive understanding of the molecular virological events and induced immunological features during SARS-CoV-2 replication can provide reliable targets for vaccine and drug development. Among the potential targets, subgenomic RNAs and their encoded proteins involved in the life cycle of SARS-CoV-2 are extremely important in viral duplication and pathogenesis. Subgenomic RNAs employ a range of coping strategies to evade immune surveillance from replication to translation, which allows RNAs to synthesize quickly, encode structural proteins efficiently and complete the entire process of virus replication and assembly successfully. This review focuses on the characteristics and functions of SARS-CoV-2 subgenomic RNAs and their encoded proteins and explores in depth the role of subgenomic RNAs in the replication and infection of host cells to provide important clues to the mechanism of COVID-19 pathogenesis.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , RNA , Virus Replication/genetics , Viral Proteins/metabolism
2.
Viruses ; 14(10)2022 10 16.
Article in English | MEDLINE | ID: covidwho-2071840

ABSTRACT

Host-virus protein interactions are critical for intracellular viral propagation. Understanding the interactions between cellular and viral proteins may help us develop new antiviral strategies. Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that causes severe damage to the global swine industry. Here, we employed co-immunoprecipitation and liquid chromatography-mass spectrometry to characterize 426 unique PEDV nucleocapsid (N) protein-binding proteins in infected Vero cells. A protein-protein interaction network (PPI) was created, and gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) database analyses revealed that the PEDV N-bound proteins belong to different cellular pathways, such as nucleic acid binding, ribonucleoprotein complex binding, RNA methyltransferase, and polymerase activities. Interactions of the PEDV N protein with 11 putative proteins: tripartite motif containing 21, DEAD-box RNA helicase 24, G3BP stress granule assembly factor 1, heat shock protein family A member 8, heat shock protein 90 alpha family class B member 1, YTH domain containing 1, nucleolin, Y-box binding protein 1, vimentin, heterogeneous nuclear ribonucleoprotein A2/B1, and karyopherin subunit alpha 1, were further confirmed by in vitro co-immunoprecipitation assay. In summary, studying an interaction network can facilitate the identification of antiviral therapeutic strategies and novel targets for PEDV infection.


Subject(s)
Coronavirus Infections , Nucleic Acids , Porcine epidemic diarrhea virus , Swine Diseases , Chlorocebus aethiops , Swine , Animals , Porcine epidemic diarrhea virus/genetics , Vimentin/metabolism , Vero Cells , Nucleocapsid/metabolism , Nucleocapsid Proteins/genetics , Viral Proteins/metabolism , Coronavirus Infections/metabolism , Antiviral Agents/metabolism , RNA/metabolism , Heat-Shock Proteins/metabolism , Methyltransferases/metabolism , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , DEAD-box RNA Helicases/metabolism , Ribonucleoproteins/metabolism , Karyopherins/metabolism , Nucleic Acids/metabolism
3.
Front Immunol ; 13: 989298, 2022.
Article in English | MEDLINE | ID: covidwho-2065518

ABSTRACT

The heterogeneous nuclear ribonucleoproteins (hnRNPs) are a diverse family of RNA binding proteins that are implicated in RNA metabolism, such as alternative splicing, mRNA stabilization and translational regulation. According to their different cellular localization, hnRNPs display multiple functions. Most hnRNPs were predominantly located in the nucleus, but some of them could redistribute to the cytoplasm during virus infection. HnRNPs consist of different domains and motifs that enable these proteins to recognize predetermined nucleotide sequences. In the virus-host interactions, hnRNPs specifically bind to viral RNA or proteins. And some of the viral protein-hnRNP interactions require the viral RNA or other host factors as the intermediate. Through various mechanisms, hnRNPs could regulate viral translation, viral genome replication, the switch of translation to replication and virion release. This review highlights the common features and the distinguish roles of hnRNPs in the life cycle of positive single-stranded RNA viruses.


Subject(s)
Heterogeneous-Nuclear Ribonucleoproteins , Positive-Strand RNA Viruses , Animals , Heterogeneous-Nuclear Ribonucleoproteins/genetics , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , Life Cycle Stages , RNA, Messenger/metabolism , RNA, Viral/genetics , RNA, Viral/metabolism , RNA-Binding Proteins , Viral Proteins/metabolism
4.
J Virol ; 96(20): e0131822, 2022 Oct 26.
Article in English | MEDLINE | ID: covidwho-2053123

ABSTRACT

Pseudorabies virus (PRV), which is extremely infectious and can infect numerous mammals, has a risk of spillover into humans. Virus-host interactions determine viral entry and spreading. Here, we showed that neuropilin-1 (NRP1) significantly potentiates PRV infection. Mechanistically, NRP1 promoted PRV attachment and entry, and enhanced cell-to-cell fusion mediated by viral glycoprotein B (gB), gD, gH, and gL. Furthermore, through in vitro coimmunoprecipitation (Co-IP) and bimolecular fluorescence complementation (BiFC) assays, NRP1 was found to physically interact with gB, gD, and gH, and these interactions were C-end Rule (CendR) motif independent, in contrast to currently known viruses. Remarkably, we illustrated that the viral protein gB promotes NRP1 degradation via a lysosome-dependent pathway. We further demonstrate that gB promotes NRP1 degradation in a furin-cleavage-dependent manner. Interestingly, in this study, we generated gB furin cleavage site (FCS)-knockout PRV (Δfurin PRV) and evaluated its pathogenesis; in vivo, we found that Δfurin PRV virulence was significantly attenuated in mice. Together, our findings demonstrated that NRP1 is an important host factor for PRV and that NRP1 may be a potential target for antiviral intervention. IMPORTANCE Recent studies have shown accelerated PRV cross-species spillover and that PRV poses a potential threat to humans. PRV infection in humans always manifests as a high fever, tonic-clonic seizures, and encephalitis. Therefore, understanding the interaction between PRV and host factors may contribute to the development of new antiviral strategies against PRV. NRP1 has been demonstrated to be a receptor for several viruses that harbor CendR, including SARS-CoV-2. However, the relationships between NRP1 and PRV are poorly understood. Here, we found that NRP1 significantly potentiated PRV infection by promoting PRV attachment and enhanced cell-to-cell fusion. For the first time, we demonstrated that gB promotes NRP1 degradation via a lysosome-dependent pathway. Last, in vivo, Δfurin PRV virulence was significantly attenuated in mice. Therefore, NRP1 is an important host factor for PRV, and NRP1 may be a potential target for antiviral drug development.


Subject(s)
COVID-19 , Herpesvirus 1, Suid , Pseudorabies , Mice , Humans , Animals , Herpesvirus 1, Suid/metabolism , Neuropilin-1/genetics , Neuropilin-1/metabolism , Furin/metabolism , SARS-CoV-2 , Viral Envelope Proteins/genetics , Viral Envelope Proteins/metabolism , Virus Replication , Viral Proteins/metabolism , Antiviral Agents/metabolism , Mammals
5.
Nature ; 610(7931): 381-388, 2022 10.
Article in English | MEDLINE | ID: covidwho-2050416

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged at the end of 2019 and caused the devastating global pandemic of coronavirus disease 2019 (COVID-19), in part because of its ability to effectively suppress host cell responses1-3. In rare cases, viral proteins dampen antiviral responses by mimicking critical regions of human histone proteins4-8, particularly those containing post-translational modifications required for transcriptional regulation9-11. Recent work has demonstrated that SARS-CoV-2 markedly disrupts host cell epigenetic regulation12-14. However, how SARS-CoV-2 controls the host cell epigenome and whether it uses histone mimicry to do so remain unclear. Here we show that the SARS-CoV-2 protein encoded by ORF8 (ORF8) functions as a histone mimic of the ARKS motifs in histone H3 to disrupt host cell epigenetic regulation. ORF8 is associated with chromatin, disrupts regulation of critical histone post-translational modifications and promotes chromatin compaction. Deletion of either the ORF8 gene or the histone mimic site attenuates the ability of SARS-CoV-2 to disrupt host cell chromatin, affects the transcriptional response to infection and attenuates viral genome copy number. These findings demonstrate a new function of ORF8 and a mechanism through which SARS-CoV-2 disrupts host cell epigenetic regulation. Further, this work provides a molecular basis for the finding that SARS-CoV-2 lacking ORF8 is associated with decreased severity of COVID-19.


Subject(s)
COVID-19 , Epigenesis, Genetic , Histones , Host Microbial Interactions , Molecular Mimicry , SARS-CoV-2 , Viral Proteins , COVID-19/genetics , COVID-19/metabolism , COVID-19/virology , Chromatin/genetics , Chromatin/metabolism , Chromatin Assembly and Disassembly , Epigenome/genetics , Histones/chemistry , Histones/metabolism , Humans , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Proteins/metabolism
6.
Protein Sci ; 31(11): e4451, 2022 11.
Article in English | MEDLINE | ID: covidwho-2047915

ABSTRACT

In most severe cases, SARS-CoV-2-induced autoimmune reactions have been associated with hemolytic complications. Hemolysis-derived heme from ruptured red blood cells has been shown to trigger a variety of fatal proinflammatory and procoagulant effects, which might deteriorate the progression of COVID-19. In addition, the virus itself can induce proinflammatory signals via the accessory protein 7a. Direct heme binding to the SARS-CoV-2 protein 7a ectodomain and other COVID-19-related proteins has been suggested earlier. Here, we report the experimental analysis of heme binding to the viral proteins spike glycoprotein, protein 7a as well as the host protein ACE2. Thus, protein 7a chemical synthesis was established, including an in-depth analysis of the three different disulfide-bonded isomers. Surface plasmon resonance spectroscopy and in silico studies confirm a transient, biphasic binding behavior, and heme-binding affinities in the nano- to low micromolar range. These results confirm the presence of the earlier identified heme-binding motifs and emphasize the relevance for consideration of labile heme in preexisting or SARS-CoV-2-induced hemolytic conditions in COVID-19 patients.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Angiotensin-Converting Enzyme 2 , Viral Proteins/metabolism , Heme , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/metabolism , Protein Binding
7.
Pak J Biol Sci ; 25(9): 867-874, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-2030108

ABSTRACT

<b>Background and Objective:</b> Lemongrass (<i>Cymbopogon citratus</i>) and turmeric (<i>Curcuma longa</i>) are widely used by the community for traditional medicinal spices and cooking spices. In the era of the COVID-19 pandemic, people use lemongrass and turmeric to increase immunity and protect the body from infection with the SARS-CoV-2 virus. However, the antiviral mechanisms have not been studied much. This study aims to predict the bioactivity of the phytosterol compounds of lemongrass and turmeric for COVID-19 therapy through inhibition of 3C-like protease (3CLPro) <i>in silico</i>. <b>Materials and Methods:</b> The 3CLPro protein 3D structure was downloaded from the PDB database with the access code 2ZU2 and the phytosterol compounds of lemongrass and turmeric were taken from PubChem. A total of 59 total phytosterol compounds from turmeric and lemongrass were screened for their bioactivity as an antiviral by using online PASS. Compounds with a high activating potential (Pa) were interacted with 3CLPro protein with the PyRx program and analyzed by Discovery Studio version 19.0 and LigPlus. <b>Results:</b> A total of 22 total phytosterol compounds were identified as potential antiviral agents. Based on the Pa value, 15 phytosterol compounds have the potential to act as inhibitor agents for 3CLPro SARS-CoV-2. The phytosterol compounds of lemongrass and turmeric bind to the 3CLPro protein in the N-finger domain region and the A and B domain inhibitors connect residues of the 3CLPro protein. The phytosterols of lemongrass and turmeric show a low binding affinity with 3CLPro SARS-CoV-2, indicating a strong interaction between ligand and protein. The inhibition of phytosterols against 3CLPro protein can be used as a basis for determining candidates for COVID-19 therapeutic agents. <b>Conclusion:</b> The phytosterol compounds contained in lemongrass and turmeric have the potential to act as 3CLPro inhibitors. Further studies both <i>in vitro</i> and <i>in vivo</i> need to be done to prove the inhibitory potential of phytosterol compounds.


Subject(s)
COVID-19 , Cymbopogon , Phytosterols , Antiviral Agents/pharmacology , COVID-19/drug therapy , Curcuma , Humans , Pandemics , Peptide Hydrolases , Phytosterols/pharmacology , SARS-CoV-2 , Viral Proteins/chemistry , Viral Proteins/metabolism
8.
PLoS Pathog ; 18(8): e1010349, 2022 08.
Article in English | MEDLINE | ID: covidwho-2021976

ABSTRACT

SARS-CoV-2 is a betacoronavirus and the etiological agent of COVID-19, a devastating infectious disease. Due to its far-reaching effect on human health, there is an urgent and growing need to understand the viral molecular biology of SARS-CoV-2 and its interaction with the host cell. SARS-CoV-2 encodes 9 predicted accessory proteins, which are presumed to be dispensable for in vitro replication, most likely having a role in modulating the host cell environment to aid viral replication. Here we show that the ORF6 accessory protein interacts with cellular Rae1 to inhibit cellular protein production by blocking mRNA export. We utilised cell fractionation coupled with mRNAseq to explore which cellular mRNA species are affected by ORF6 expression and show that ORF6 can inhibit the export of many mRNA including those encoding antiviral factors such as IRF1 and RIG-I. We also show that export of these mRNA is blocked in the context of SARS-CoV-2 infection. Together, our studies identify a novel mechanism by which SARS-CoV-2 can manipulate the host cell environment to supress antiviral responses, providing further understanding to the replication strategies of a virus that has caused an unprecedented global health crisis.


Subject(s)
COVID-19 , SARS-CoV-2 , Viral Proteins/metabolism , Antiviral Agents , COVID-19/genetics , Humans , Immunity, Innate , Nuclear Matrix-Associated Proteins , Nucleocytoplasmic Transport Proteins/genetics , RNA, Messenger/genetics
11.
J Virol ; 96(17): e0074122, 2022 09 14.
Article in English | MEDLINE | ID: covidwho-1992937

ABSTRACT

Within the past 2 decades, three highly pathogenic human coronaviruses have emerged, namely, severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The health threats and economic burden posed by these tremendously severe coronaviruses have paved the way for research on their etiology, pathogenesis, and treatment. Compared to SARS-CoV and SARS-CoV-2, MERS-CoV genome encoded fewer accessory proteins, among which the ORF4b protein had anti-immunity ability in both the cytoplasm and nucleus. Our work for the first time revealed that ORF4b protein was unstable in the host cells and could be degraded by the ubiquitin proteasome system. After extensive screenings, it was found that UBR5 (ubiquitin protein ligase E3 component N-recognin 5), a member of the HECT E3 ubiquitin ligases, specifically regulated the ubiquitination and degradation of ORF4b. Similar to ORF4b, UBR5 can also translocate into the nucleus through its nuclear localization signal, enabling it to regulate ORF4b stability in both the cytoplasm and nucleus. Through further experiments, lysine 36 was identified as the ubiquitination site on the ORF4b protein, and this residue was highly conserved in various MERS-CoV strains isolated from different regions. When UBR5 was knocked down, the ability of ORF4b to suppress innate immunity was enhanced and MERS-CoV replication was stronger. As an anti-MERS-CoV host protein, UBR5 targets and degrades ORF4b protein through the ubiquitin proteasome system, thereby attenuating the anti-immunity ability of ORF4b and ultimately inhibiting MERS-CoV immune escape, which is a novel antagonistic mechanism of the host against MERS-CoV infection. IMPORTANCE ORF4b was an accessory protein unique to MERS-CoV and was not present in SARS-CoV and SARS-CoV-2 which can also cause severe respiratory disease. Moreover, ORF4b inhibited the production of antiviral cytokines in both the cytoplasm and the nucleus, which was likely to be associated with the high lethality of MERS-CoV. However, whether the host proteins regulate the function of ORF4b is unknown. Our study first determined that UBR5, a host E3 ligase, was a potential host anti-MERS-CoV protein that could reduce the protein level of ORF4b and diminish its anti-immunity ability by inducing ubiquitination and degradation. Based on the discovery of ORF4b-UBR5, a critical molecular target, further increasing the degradation of ORF4b caused by UBR5 could provide a new strategy for the clinical development of drugs for MERS-CoV.


Subject(s)
Coronavirus Infections , Host Microbial Interactions , Middle East Respiratory Syndrome Coronavirus , Proteolysis , Ubiquitin-Protein Ligases , Ubiquitination , Viral Proteins , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Cytokines/immunology , Humans , Immunity, Innate , Middle East Respiratory Syndrome Coronavirus/immunology , Middle East Respiratory Syndrome Coronavirus/metabolism , Molecular Targeted Therapy , Proteasome Endopeptidase Complex/metabolism , SARS Virus , SARS-CoV-2 , Ubiquitin-Protein Ligases/metabolism , Ubiquitins/metabolism , Viral Proteins/chemistry , Viral Proteins/metabolism , Virus Replication
12.
Nature ; 609(7928): 793-800, 2022 09.
Article in English | MEDLINE | ID: covidwho-1984402

ABSTRACT

The RNA genome of SARS-CoV-2 contains a 5' cap that facilitates the translation of viral proteins, protection from exonucleases and evasion of the host immune response1-4. How this cap is made in SARS-CoV-2 is not completely understood. Here we reconstitute the N7- and 2'-O-methylated SARS-CoV-2 RNA cap (7MeGpppA2'-O-Me) using virally encoded non-structural proteins (nsps). We show that the kinase-like nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain5 of nsp12 transfers the RNA to the amino terminus of nsp9, forming a covalent RNA-protein intermediate (a process termed RNAylation). Subsequently, the NiRAN domain transfers the RNA to GDP, forming the core cap structure GpppA-RNA. The nsp146 and nsp167 methyltransferases then add methyl groups to form functional cap structures. Structural analyses of the replication-transcription complex bound to nsp9 identified key interactions that mediate the capping reaction. Furthermore, we demonstrate in a reverse genetics system8 that the N terminus of nsp9 and the kinase-like active-site residues in the NiRAN domain are required for successful SARS-CoV-2 replication. Collectively, our results reveal an unconventional mechanism by which SARS-CoV-2 caps its RNA genome, thus exposing a new target in the development of antivirals to treat COVID-19.


Subject(s)
RNA Caps , RNA, Viral , SARS-CoV-2 , Viral Proteins , Antiviral Agents , COVID-19/drug therapy , COVID-19/virology , Catalytic Domain , Guanosine Diphosphate/metabolism , Humans , Methyltransferases/metabolism , Nucleotidyltransferases/chemistry , Nucleotidyltransferases/metabolism , Protein Domains , RNA Caps/chemistry , RNA Caps/genetics , RNA Caps/metabolism , RNA, Viral/chemistry , RNA, Viral/genetics , RNA, Viral/metabolism , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2/enzymology , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Viral Proteins/chemistry , Viral Proteins/metabolism
13.
J Med Virol ; 93(11): 6116-6123, 2021 11.
Article in English | MEDLINE | ID: covidwho-1349155

ABSTRACT

Virus invasion activates the host's innate immune response, inducing the production of numerous cytokines and interferons to eliminate pathogens. Except for viral DNA/RNA, viral proteins are also targets of pattern recognition receptors. Membrane-bound receptors such as Toll-like receptor (TLR)1, TLR2, TLR4, TLR6, and TLR10 relate to the recognition of viral proteins. Distinct TLRs perform both protective and detrimental roles for a specific virus. Here, we review viral proteins serving as pathogen-associated molecular patterns and their corresponding TLRs. These viruses are all enveloped, including respiratory syncytial virus, hepatitis C virus, measles virus, herpesvirus human immunodeficiency virus, and coronavirus, and can encode proteins to activate innate immunity in a TLR-dependent way. The TLR-viral protein relationship plays an important role in innate immunity activation. A detailed understanding of their pathways contributes to a novel direction for vaccine development.


Subject(s)
Immunity, Innate , Pathogen-Associated Molecular Pattern Molecules/metabolism , Toll-Like Receptors/immunology , Toll-Like Receptors/metabolism , Viral Proteins/metabolism , Virus Diseases/immunology , Viruses/immunology , Animals , HIV/immunology , HIV/metabolism , HIV/pathogenicity , Hepacivirus/immunology , Hepacivirus/metabolism , Hepacivirus/pathogenicity , Herpesviridae/immunology , Herpesviridae/metabolism , Herpesviridae/pathogenicity , Humans , Measles virus/immunology , Measles virus/metabolism , Measles virus/pathogenicity , Pathogen-Associated Molecular Pattern Molecules/chemistry , Respiratory Syncytial Viruses/immunology , Respiratory Syncytial Viruses/metabolism , Respiratory Syncytial Viruses/pathogenicity , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Viral Proteins/chemistry , Virus Diseases/virology , Viruses/metabolism , Viruses/pathogenicity
14.
Viruses ; 13(8)2021 08 05.
Article in English | MEDLINE | ID: covidwho-1390162

ABSTRACT

Nucleotidylylation is a post-transcriptional modification important for replication in the picornavirus supergroup of RNA viruses, including members of the Caliciviridae, Coronaviridae, Picornaviridae and Potyviridae virus families. This modification occurs when the RNA-dependent RNA polymerase (RdRp) attaches one or more nucleotides to a target protein through a nucleotidyl-transferase reaction. The most characterized nucleotidylylation target is VPg (viral protein genome-linked), a protein linked to the 5' end of the genome in Caliciviridae, Picornaviridae and Potyviridae. The nucleotidylylation of VPg by RdRp is a critical step for the VPg protein to act as a primer for genome replication and, in Caliciviridae and Potyviridae, for the initiation of translation. In contrast, Coronaviridae do not express a VPg protein, but the nucleotidylylation of proteins involved in replication initiation is critical for genome replication. Furthermore, the RdRp proteins of the viruses that perform nucleotidylylation are themselves nucleotidylylated, and in the case of coronavirus, this has been shown to be essential for viral replication. This review focuses on nucleotidylylation within the picornavirus supergroup of viruses, including the proteins that are modified, what is known about the nucleotidylylation process and the roles that these modifications have in the viral life cycle.


Subject(s)
Nucleotides/metabolism , Positive-Strand RNA Viruses/metabolism , RNA-Dependent RNA Polymerase/metabolism , Viral Proteins/metabolism , Caliciviridae/genetics , Caliciviridae/metabolism , Coronaviridae/genetics , Coronaviridae/metabolism , Genome, Viral , Nidovirales/genetics , Nidovirales/metabolism , Picornaviridae/genetics , Picornaviridae/metabolism , Positive-Strand RNA Viruses/genetics , Potyviridae/genetics , Potyviridae/metabolism , RNA, Viral/genetics , RNA, Viral/metabolism , Virus Replication
15.
Front Immunol ; 13: 891816, 2022.
Article in English | MEDLINE | ID: covidwho-1969020

ABSTRACT

An important number of studies have been conducted on the potential association between human leukocyte antigen (HLA) genes and COVID-19 susceptibility and severity since the beginning of the pandemic. However, case-control and peptide-binding prediction methods tended to provide inconsistent conclusions on risk and protective HLA alleles, whereas some researchers suggested the importance of considering the overall capacity of an individual's HLA Class I molecules to present SARS-CoV-2-derived peptides. To close the gap between these approaches, we explored the distributions of HLA-A, -B, -C, and -DRB1 1st-field alleles in 142 Iranian patients with COVID-19 and 143 ethnically matched healthy controls, and applied in silico predictions of bound viral peptides for each individual's HLA molecules. Frequency comparison revealed the possible predisposing roles of HLA-A*03, B*35, and DRB1*16 alleles and the protective effect of HLA-A*32, B*58, B*55, and DRB1*14 alleles in the viral infection. None of these results remained significant after multiple testing corrections, except HLA-A*03, and no allele was associated with severity, either. Compared to peptide repertoires of individual HLA molecules that are more likely population-specific, the overall coverage of virus-derived peptides by one's HLA Class I molecules seemed to be a more prominent factor associated with both COVID-19 susceptibility and severity, which was independent of affinity index and threshold chosen, especially for people under 60 years old. Our results highlight the effect of the binding capacity of different HLA Class I molecules as a whole, and the more essential role of HLA-A compared to HLA-B and -C genes in immune responses against SARS-CoV-2 infection.


Subject(s)
COVID-19 , Histocompatibility Antigens Class I , Viral Proteins , COVID-19/genetics , HLA-A Antigens/genetics , HLA-A Antigens/metabolism , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/metabolism , Humans , Iran , Middle Aged , Protein Binding , SARS-CoV-2 , Viral Proteins/metabolism
16.
Neurotox Res ; 40(5): 1553-1569, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-1966190

ABSTRACT

Since the appearance of SARS-CoV-2 and the COVID-19 pandemic, the search for new approaches to treat this disease took place in the scientific community. The in silico approach has gained importance at this moment, once the methodologies used in this kind of study allow for the identification of specific protein-ligand interactions, which may serve as a filter step for molecules that can act as specific inhibitors. In addition, it is a low-cost and high-speed technology. Molecular docking has been widely used to find potential viral protein inhibitors for structural and non-structural proteins of the SARS-CoV-2, aiming to block the infection and the virus multiplication. The papain-like protease (PLpro) participates in the proteolytic processing of SARS-CoV-2 and composes one of the main targets studied for pharmacological intervention by in silico methodologies. Based on that, we performed a systematic review about PLpro inhibitors from the perspective of in silico research, including possible therapeutic molecules in relation to this viral protein. The neurological problems triggered by COVID-19 were also briefly discussed, especially relative to the similarities of neuroinflammation present in Alzheimer's disease. In this context, we focused on two molecules, curcumin and glycyrrhizinic acid, given their PLpro inhibitory actions and neuroprotective properties and potential therapeutic effects on COVID-19.


Subject(s)
COVID-19 , Curcumin , COVID-19/drug therapy , Glycyrrhizic Acid , Humans , Ligands , Molecular Docking Simulation , Pandemics , Papain/chemistry , Papain/metabolism , Peptide Hydrolases/metabolism , SARS-CoV-2 , Viral Proteins/chemistry , Viral Proteins/metabolism
17.
J Food Biochem ; 46(10): e14354, 2022 10.
Article in English | MEDLINE | ID: covidwho-1956771

ABSTRACT

Coronavirus disease 2019 (COVID-19) is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several vaccines against SARS-CoV-2 have been approved; however, variants of concern (VOCs) can evade vaccine protection. Therefore, developing small compound drugs that directly block the interaction between the viral spike glycoprotein and ACE2 is urgently needed to provide a complementary or alternative treatment for COVID-19 patients. We developed a viral infection assay to screen a library of approximately 126 small molecules and showed that peimine inhibits VOCs viral infections. In addition, a fluorescence resonance energy transfer (FRET) assay showed that peimine suppresses the interaction of spike and ACE2. Molecular docking analysis revealed that peimine exhibits a higher binding affinity for variant spike proteins and is able to form hydrogen bonds with N501Y in the spike protein. These results suggest that peimine, a compound isolated from Fritillaria, may be a potent inhibitor of SARS-CoV-2 variant infection. PRACTICAL APPLICATIONS: In this study, we identified a naturally derived compound of peimine, a major bioactive alkaloid extracted from Fritillaria, that could inhibit SARS-CoV-2 variants of concern (VOCs) viral infection in 293T/ACE2 and Calu-3 lung cells. In addition, peimine blocks viral entry through interruption of spike and ACE2 interaction. Moreover, molecular docking analysis demonstrates that peimine has a higher binding affinity on N501Y in the spike protein. Furthermore, we found that Fritillaria significantly inhibits SARS-CoV-2 viral infection. These results suggested that peimine and Fritillaria could be a potential functional drug and food for COVID-19 patients.


Subject(s)
COVID-19 , Cevanes , Angiotensin-Converting Enzyme 2/genetics , Binding Sites , COVID-19/drug therapy , COVID-19 Vaccines , Glycoproteins , Humans , Molecular Docking Simulation , Peptidyl-Dipeptidase A/chemistry , Protein Binding , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Viral Proteins/metabolism , Virus Internalization
18.
Molecules ; 27(10)2022 May 23.
Article in English | MEDLINE | ID: covidwho-1953751

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 is a global burden on human health and economy. The 3-Chymotrypsin-like cysteine protease (3CLpro) becomes an attractive target for SARS-CoV-2 due to its important role in viral replication. We synthesized a series of 8H-indeno[1,2-d]thiazole derivatives and evaluated their biochemical activities against SARS-CoV-2 3CLpro. Among them, the representative compound 7a displayed inhibitory activity with an IC50 of 1.28 ± 0.17 µM against SARS-CoV-2 3CLpro. Molecular docking of 7a against 3CLpro was performed and the binding mode was rationalized. These preliminary results provide a unique prototype for the development of novel inhibitors against SARS-CoV-2 3CLpro.


Subject(s)
COVID-19 , Protease Inhibitors , COVID-19/drug therapy , Cysteine Endopeptidases/chemistry , Humans , Molecular Docking Simulation , Pandemics , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , SARS-CoV-2 , Thiazoles/pharmacology , Viral Proteins/metabolism
19.
Front Cell Infect Microbiol ; 12: 899546, 2022.
Article in English | MEDLINE | ID: covidwho-1952264

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global pandemic that has currently infected over 430 million individuals worldwide. With the variant strains of SARS-CoV-2 emerging, a region of high mutation rates in ORF8 was identified during the early pandemic, which resulted in a mutation from leucine (L) to serine (S) at amino acid 84. A typical feature of ORF8 is the immune evasion by suppressing interferon response; however, the mechanisms by which the two variants of ORF8 antagonize the type I interferon (IFN-I) pathway have not yet been clearly investigated. Here, we reported that SARS-CoV-2 ORF8L and ORF8S with no difference inhibit the production of IFN-ß, MDA5, RIG-I, ISG15, ISG56, IRF3, and other IFN-related genes induced by poly(I:C). In addition, both ORF8L and ORF8S proteins were found to suppress the nuclear translocation of IRF3. Mechanistically, the SARS-CoV-2 ORF8 protein interacts with HSP90B1, which was later investigated to induce the production of IFN-ß and IRF3. Taken together, these results indicate that SARS-CoV-2 ORF8 antagonizes the RIG-I/MDA-5 signaling pathway by targeting HSP90B1, which subsequently exhibits an inhibitory effect on the production of IFN-I. These functions appeared not to be influenced by the genotypes of ORF8L and ORF8S. Our study provides an explanation for the antiviral immune suppression of SARS-CoV-2 and suggests implications for the pathogenic mechanism and treatment of COVID-19.


Subject(s)
COVID-19 , Interferon Type I , Membrane Glycoproteins , Viral Proteins , COVID-19/virology , Humans , Immune Evasion , Interferon Type I/metabolism , Interferon-beta/genetics , Membrane Glycoproteins/metabolism , SARS-CoV-2 , Signal Transduction , Viral Proteins/metabolism
20.
Front Cell Infect Microbiol ; 12: 852473, 2022.
Article in English | MEDLINE | ID: covidwho-1938605

ABSTRACT

Porcine sapelovirus (PSV) is the causative pathogen of reproductive obstacles, acute diarrhea, respiratory distress, or severe polioencephalomyelitis in swine. Nevertheless, the pathogenicity and pathogenic mechanism of PSV infection are not fully understood, which hinders disease prevention and control. In this study, we found that PSV was sensitive to type I interferon (IFN-ß). However, PSV could not activate the IFN-ß promoter and induce IFN-ß mRNA expression, indicating that PSV has evolved an effective mechanism to block IFN-ß production. Further study showed that PSV inhibited the production of IFN-ß by cleaving mitochondrial antiviral signaling (MAVS) and degrading melanoma differentiation-associated gene 5 (MDA5) and TANK-binding kinase 1 (TBK1) through viral 3Cpro. In addition, our study demonstrated that PSV 3Cpro degrades MDA5 and TBK1 through its protease activity and cleaves MAVS through the caspase pathway. Collectively, our results revealed that PSV inhibits the production of type I interferon to escape host antiviral immunity through cleaving and degrading the adaptor molecules.


Subject(s)
Interferon Type I , Picornaviridae , Animals , Antiviral Agents , Cysteine Endopeptidases/metabolism , Interferon Type I/metabolism , Interferon-beta/metabolism , Swine , Viral Proteins/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL