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1.
Nat Immunol ; 22(11): 1416-1427, 2021 11.
Article in English | MEDLINE | ID: covidwho-1475314

ABSTRACT

Ubiquitin-like protein ISG15 (interferon-stimulated gene 15) (ISG15) is a ubiquitin-like modifier induced during infections and involved in host defense mechanisms. Not surprisingly, many viruses encode deISGylating activities to antagonize its effect. Here we show that infection by Zika, SARS-CoV-2 and influenza viruses induce ISG15-modifying enzymes. While influenza and Zika viruses induce ISGylation, SARS-CoV-2 triggers deISGylation instead to generate free ISG15. The ratio of free versus conjugated ISG15 driven by the papain-like protease (PLpro) enzyme of SARS-CoV-2 correlates with macrophage polarization toward a pro-inflammatory phenotype and attenuated antigen presentation. In vitro characterization of purified wild-type and mutant PLpro revealed its strong deISGylating over deubiquitylating activity. Quantitative proteomic analyses of PLpro substrates and secretome from SARS-CoV-2-infected macrophages revealed several glycolytic enzymes previously implicated in the expression of inflammatory genes and pro-inflammatory cytokines, respectively. Collectively, our results indicate that altered free versus conjugated ISG15 dysregulates macrophage responses and probably contributes to the cytokine storms triggered by SARS-CoV-2.


Subject(s)
COVID-19/immunology , Cytokines/metabolism , Inflammation/immunology , Macrophages/immunology , SARS-CoV-2/physiology , Ubiquitins/metabolism , Cell Differentiation , Coronavirus Papain-Like Proteases/metabolism , Cytokines/genetics , Gene Knockdown Techniques , HeLa Cells , Humans , Immune Evasion , Immunity, Innate , Influenza A virus/physiology , Influenza, Human/immunology , Pluripotent Stem Cells/cytology , Ubiquitination , Ubiquitins/genetics , Zika Virus/physiology , Zika Virus Infection/immunology
2.
Cytokine ; 140: 155430, 2021 04.
Article in English | MEDLINE | ID: covidwho-1385381

ABSTRACT

In vitro interferon (IFN)α treatment of primary human upper airway basal cells has been shown to drive ACE2 expression, the receptor of SARS-CoV-2. The protease furin is also involved in mediating SARS-CoV-2 and other viral infections, although its association with early IFN response has not been evaluated yet. In order to assess the in vivo relationship between ACE2 and furin expression and the IFN response in nasopharyngeal cells, we first examined ACE2 and furin levels and their correlation with the well-known marker of IFNs' activation, ISG15, in children (n = 59) and adults (n = 48), during respiratory diseases not caused by SARS-CoV-2. A strong positive correlation was found between ACE2 expression, but not of furin, and ISG15 in all patients analyzed. In addition, type I and III IFN stimulation experiments were performed to examine the IFN-mediated activation of ACE2 isoforms (full-length and truncated) and furin in epithelial cell lines. Following all the IFNs treatments, only the truncated ACE2 levels, were upregulated significantly in the A549 and Calu3 cells, in particular by type I IFNs. If confirmed in vivo following IFNs' activation, the induction of the truncated ACE2 isoform only would not enhance the risk of SARS-CoV-2 infection in the respiratory tract.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , COVID-19/prevention & control , Epithelial Cells/drug effects , Gene Expression/drug effects , Interferons/pharmacology , SARS-CoV-2/drug effects , A549 Cells , Adult , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , COVID-19/virology , Cell Line, Tumor , Child , Cytokines/genetics , Epithelial Cells/metabolism , Humans , Interferons/metabolism , Lung/cytology , Middle Aged , SARS-CoV-2/physiology , Ubiquitins/genetics
3.
Signal Transduct Target Ther ; 5(1): 221, 2020 10 06.
Article in English | MEDLINE | ID: covidwho-1387195
4.
Immunol Lett ; 237: 33-41, 2021 09.
Article in English | MEDLINE | ID: covidwho-1293862

ABSTRACT

OBJECTIVE: In this study, we focused on the interaction between SARS-CoV-2 and host Type I Interferon (IFN) response, so as to identify whether IFN effects could be influenced by the products of SARS-CoV-2. METHODS: All the structural and non-structural proteins of SARS-CoV-2 were transfected and overexpressed in the bronchial epithelial cell line BEAS-2B respectively, and typical antiviral IFN-stimulated gene (ISG) ISG15 expression was detected by qRT-PCR. RNA-seq based transcriptome analysis was performed between control and Spike (S) protein-overexpressed BEAS-2B cells. The expression of ACE2 and IFN effector JAK-STAT signaling activation were detected in control and S protein-overexpressed BEAS-2B cells by qRT-PCR or/and Western blot respectively. The interaction between S protein with STAT1 and STAT2, and the association between JAK1 with downstream STAT1 and STAT2 were measured in BEAS-2B cells by co-immunoprecipitation (co-IP). RESULTS: S protein could activate IFN effects and downstream ISGs expression. By transcriptome analysis, overexpression of S protein induced a set of genes expression, including series of ISGs and the SARS-CoV-2 receptor ACE2. Mechanistically, S protein enhanced the association between the upstream JAK1 and downstream STAT1 and STAT2, so as to promote STAT1 and STAT2 phosphorylation and ACE2 expression. CONCLUSION: SARS-CoV-2 S protein enhances ACE2 expression via facilitating IFN effects, which may help its infection.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Bronchi/drug effects , COVID-19/virology , Epithelial Cells/drug effects , Interferon alpha-2/pharmacology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2/genetics , Bronchi/enzymology , Bronchi/virology , COVID-19/enzymology , Cytokines/genetics , Cytokines/metabolism , Epithelial Cells/enzymology , Epithelial Cells/virology , HEK293 Cells , Host-Pathogen Interactions , Humans , Janus Kinase 1/metabolism , Phosphorylation , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , STAT1 Transcription Factor/metabolism , STAT2 Transcription Factor/metabolism , Signal Transduction , Spike Glycoprotein, Coronavirus/genetics , Ubiquitins/genetics , Ubiquitins/metabolism , Up-Regulation
5.
Viruses ; 13(6)2021 06 09.
Article in English | MEDLINE | ID: covidwho-1282639

ABSTRACT

Mammalian cells have developed an elaborate network of immunoproteins that serve to identify and combat viral pathogens. Interferon-stimulated gene 15 (ISG15) is a 15.2 kDa tandem ubiquitin-like protein (UBL) that is used by specific E1-E2-E3 ubiquitin cascade enzymes to interfere with the activity of viral proteins. Recent biochemical studies have demonstrated how the E3 ligase HECT and RCC1-containing protein 5 (HERC5) regulates ISG15 signaling in response to hepatitis C (HCV), influenza-A (IAV), human immunodeficiency virus (HIV), SARS-CoV-2 and other viral infections. Taken together, the potent antiviral activity displayed by HERC5 and ISG15 make them promising drug targets for the development of novel antiviral therapeutics that can augment the host antiviral response. In this review, we examine the emerging role of ISG15 in antiviral immunity with a particular focus on how HERC5 orchestrates the specific and timely ISGylation of viral proteins in response to infection.


Subject(s)
Cytokines/genetics , Interferons/immunology , Intracellular Signaling Peptides and Proteins/genetics , Ubiquitins/genetics , Virus Diseases/immunology , Animals , COVID-19/immunology , Cytokines/immunology , HeLa Cells , Humans , Intracellular Signaling Peptides and Proteins/immunology , Mice , SARS-CoV-2/immunology , Ubiquitins/immunology , Viral Proteins/genetics , Viral Proteins/metabolism
6.
J Phys Chem Lett ; 12(23): 5608-5615, 2021 Jun 17.
Article in English | MEDLINE | ID: covidwho-1263456

ABSTRACT

Papain-like protease (PLpro) from SARS-CoV-2 plays essential roles in the replication cycle of the virus. In particular, it preferentially interacts with and cleaves human interferon-stimulated gene 15 (hISG15) to suppress the innate immune response of the host. We used small-angle X-ray and neutron scattering combined with computational techniques to study the mechanism of interaction of SARS-CoV-2 PLpro with hISG15. We showed that hISG15 undergoes a transition from an extended to a compact state after binding to PLpro, a conformation that has not been previously observed in complexes of SARS-CoV-2 PLpro with ISG15 from other species. Furthermore, computational analysis showed significant conformational flexibility in the ISG15 N-terminal domain, suggesting that it is weakly bound to PLpro and supports a binding mechanism that is dominated by the C-terminal ISG15 domain. This study fundamentally improves our understanding of the SARS-CoV-2 deISGylation complex that will help guide development of COVID-19 therapeutics targeting this complex.


Subject(s)
Coronavirus Papain-Like Proteases/chemistry , Coronavirus Papain-Like Proteases/metabolism , Cytokines/chemistry , Cytokines/metabolism , Interferons/metabolism , SARS-CoV-2/metabolism , Ubiquitins/chemistry , Ubiquitins/metabolism , Coronavirus Papain-Like Proteases/genetics , Cytokines/genetics , Humans , Neutron Diffraction , Protein Conformation , SARS-CoV-2/enzymology , SARS-CoV-2/genetics , Scattering, Small Angle , Ubiquitins/genetics , X-Ray Diffraction
7.
EMBO J ; 39(18): e106275, 2020 09 15.
Article in English | MEDLINE | ID: covidwho-730426

ABSTRACT

The SARS-CoV-2 coronavirus encodes an essential papain-like protease domain as part of its non-structural protein (nsp)-3, namely SARS2 PLpro, that cleaves the viral polyprotein, but also removes ubiquitin-like ISG15 protein modifications as well as, with lower activity, Lys48-linked polyubiquitin. Structures of PLpro bound to ubiquitin and ISG15 reveal that the S1 ubiquitin-binding site is responsible for high ISG15 activity, while the S2 binding site provides Lys48 chain specificity and cleavage efficiency. To identify PLpro inhibitors in a repurposing approach, screening of 3,727 unique approved drugs and clinical compounds against SARS2 PLpro identified no compounds that inhibited PLpro consistently or that could be validated in counterscreens. More promisingly, non-covalent small molecule SARS PLpro inhibitors also target SARS2 PLpro, prevent self-processing of nsp3 in cells and display high potency and excellent antiviral activity in a SARS-CoV-2 infection model.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/metabolism , SARS-CoV-2/metabolism , Ubiquitin/metabolism , Animals , Binding Sites , Chlorocebus aethiops , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/genetics , Crystallography, X-Ray , Cytokines/genetics , Drug Evaluation, Preclinical/methods , Drug Repositioning , Fluorescence Polarization , HEK293 Cells , Humans , Kinetics , Models, Molecular , Protease Inhibitors/pharmacology , Protein Conformation , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Ubiquitins/genetics , Vero Cells
8.
Antiviral Res ; 174: 104661, 2020 02.
Article in English | MEDLINE | ID: covidwho-15315

ABSTRACT

Coronavirus papain-like proteases (PLPs or PLpro), such as the one encoded in the genome of the infectious Middle East Respiratory Syndrome (MERS) virus, have multiple enzymatic activities that promote viral infection. PLpro acts as a protease and processes the large coronavirus polyprotein for virus replication. PLpro also functions as both a deubiquitinating (DUB) and deISGylating (deISG) enzyme and removes ubiquitin (Ub) and interferon-stimulated gene 15 (ISG15) from cellular proteins. Both DUB and deISG activities are implicated in suppressing innate immune responses; however, the precise role of each activity in this process is still unclear due in part to the difficulties in separating each activity. In this study, we determine the first structure of MERS PLpro in complex with the full-length human ISG15 to a resolution of 2.3 Å. This structure and available structures of MERS PLpro-Ub complexes were used as molecular guides to design PLpro mutants that lack either or both DUB/deISG activities. We tested 13 different PLpro mutants for protease, DUB, and deISG activitites using fluorescence-based assays. Results show that we can selectively modulate DUB activity at amino acid positions 1649 and 1653 while mutation of Val1691 or His1652 of PLpro to a positive charged residue completely impairs both DUB/deISG activities. These mutant enzymes will provide new functional tools for delineating the importance of DUB versus deISG activity in virus-infected cells and may serve as potential candidates for attenuating the MERS virus in vivo for modified vaccine design efforts.


Subject(s)
Coronavirus Infections/metabolism , Cysteine Endopeptidases/metabolism , Cytokines/metabolism , Middle East Respiratory Syndrome Coronavirus/enzymology , Ubiquitins/metabolism , Viral Nonstructural Proteins/metabolism , Coronavirus 3C Proteases , Coronavirus Infections/genetics , Coronavirus Infections/virology , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/genetics , Cytokines/chemistry , Cytokines/genetics , Host-Parasite Interactions , Humans , Middle East Respiratory Syndrome Coronavirus/genetics , Protein Binding , Protein Processing, Post-Translational , Ubiquitin , Ubiquitins/chemistry , Ubiquitins/genetics , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics
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