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1.
Sci Signal ; 15(715): eabh0068, 2022 01 04.
Article in English | MEDLINE | ID: covidwho-1741564

ABSTRACT

The transcription regulator ID2 plays an essential role in the development and differentiation of immune cells. Here, we report that ID2 also negatively regulates antiviral innate immune responses. During viral infection of human epithelial cells, ID2 bound to TANK-binding kinase 1 (TBK1) and to inhibitor of nuclear factor κB kinase ε (IKKε). These interactions inhibited the recruitment and activation of interferon (IFN) regulatory factor 3 (IRF3) by TBK1 or IKKε, leading to a reduction in the expression of IFN-ß1 (IFNB1). IFN-ß induced the nuclear export of ID2 to form a negative feedback loop. Knocking out ID2 in human cells enhanced innate immune responses and suppressed infection by different viruses, including SARS-CoV-2. Mice with a myeloid-specific deficiency of ID2 produced more IFN-α in response to viral infection and were more resistant to viral infection than wild-type mice. Our findings not only establish ID2 as a modulator of IRF3 activation induced by TBK1 and/or IKKε but also introduce a mechanism for cross-talk between innate immunity and cell development and differentiation.


Subject(s)
COVID-19 , I-kappa B Kinase , Animals , Antiviral Agents , Humans , I-kappa B Kinase/genetics , I-kappa B Kinase/metabolism , Immunity, Innate , Inhibitor of Differentiation Protein 2 , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Mice , Phosphorylation , SARS-CoV-2
2.
Front Immunol ; 12: 662989, 2021.
Article in English | MEDLINE | ID: covidwho-1256380

ABSTRACT

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative pathogen of current COVID-19 pandemic, and insufficient production of type I interferon (IFN-I) is associated with the severe forms of the disease. Membrane (M) protein of SARS-CoV-2 has been reported to suppress host IFN-I production, but the underlying mechanism is not completely understood. In this study, SARS-CoV-2 M protein was confirmed to suppress the expression of IFNß and interferon-stimulated genes induced by RIG-I, MDA5, IKKϵ, and TBK1, and to inhibit IRF3 phosphorylation and dimerization caused by TBK1. SARS-CoV-2 M could interact with MDA5, TRAF3, IKKϵ, and TBK1, and induce TBK1 degradation via K48-linked ubiquitination. The reduced TBK1 further impaired the formation of TRAF3-TANK-TBK1-IKKε complex that leads to inhibition of IFN-I production. Our study revealed a novel mechanism of SARS-CoV-2 M for negative regulation of IFN-I production, which would provide deeper insight into the innate immunosuppression and pathogenicity of SARS-CoV-2.


Subject(s)
Interferon Type I/biosynthesis , SARS-CoV-2/immunology , Ubiquitin/metabolism , Viral Matrix Proteins/immunology , DEAD Box Protein 58/metabolism , HEK293 Cells , Humans , I-kappa B Kinase/metabolism , Interferon Regulatory Factor-3/metabolism , Interferon-Induced Helicase, IFIH1/metabolism , Proteolysis , Receptors, Immunologic/metabolism , Signal Transduction , TNF Receptor-Associated Factor 3/metabolism
3.
Naunyn Schmiedebergs Arch Pharmacol ; 394(3): 561-567, 2021 03.
Article in English | MEDLINE | ID: covidwho-1235720

ABSTRACT

Coronavirus disease 2019 (COVID-19) has been characterized by lymphopenia as well as a proinflammatory cytokine storm, which are responsible for the poor prognosis and multiorgan defects. The transcription factor nuclear factor-κB (NF-κB) modulates the functions of the immune cells and alters the gene expression profile of different cytokines in response to various pathogenic stimuli, while many proinflammatory factors have been known to induce NF-κB signalling cascade. Besides, NF-κB has been known to potentiate the production of reactive oxygen species (ROS) leading to apoptosis in various tissues in many diseases and viral infections. Though the reports on the involvement of the NF-κB signalling pathway in COVID-19 are limited, the therapeutic benefits of NF-κB inhibitors including dexamethasone, a synthetic form of glucocorticoid, have increasingly been realized. Considering the fact, the abnormal activation of the NF-κB resulting from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection might be associated with the pathogenic profile of immune cells, cytokine storm and multiorgan defects. Thus, the pharmacological inactivation of the NF-κB signalling pathway can strongly represent a potential therapeutic target to treat the symptomatology of COVID-19. This article signifies pharmacological blockade of the phosphorylation of inhibitor of nuclear factor kappa B kinase subunit beta (IKKß), a key downstream effector of NF-κB signalling, for a therapeutic consideration to attenuate COVID-19.


Subject(s)
COVID-19/drug therapy , Drug Delivery Systems/trends , I-kappa B Kinase/antagonists & inhibitors , NF-kappa B/antagonists & inhibitors , Signal Transduction/physiology , Animals , COVID-19/epidemiology , COVID-19/metabolism , Cytokine Release Syndrome/drug therapy , Cytokine Release Syndrome/epidemiology , Cytokine Release Syndrome/metabolism , Heterocyclic Compounds, 3-Ring/administration & dosage , Humans , I-kappa B Kinase/metabolism , Lymphopenia/drug therapy , Lymphopenia/epidemiology , Lymphopenia/metabolism , NF-kappa B/metabolism , Nitriles/administration & dosage , Pyridines/administration & dosage , Signal Transduction/drug effects , Sulfones/administration & dosage
4.
J Immunol ; 205(6): 1564-1579, 2020 09 15.
Article in English | MEDLINE | ID: covidwho-694818

ABSTRACT

Middle East respiratory syndrome coronavirus (MERS-CoV) is a highly pathogenic human coronavirus causing severe disease and mortality. MERS-CoV infection failed to elicit robust IFN response, suggesting that the virus might have evolved strategies to evade host innate immune surveillance. In this study, we identified and characterized type I IFN antagonism of MERS-CoV open reading frame (ORF) 8b accessory protein. ORF8b was abundantly expressed in MERS-CoV-infected Huh-7 cells. When ectopically expressed, ORF8b inhibited IRF3-mediated IFN-ß expression induced by Sendai virus and poly(I:C). ORF8b was found to act at a step upstream of IRF3 to impede the interaction between IRF3 kinase IKKε and chaperone protein HSP70, which is required for the activation of IKKε and IRF3. An infection study using recombinant wild-type and ORF8b-deficient MERS-CoV further confirmed the suppressive role of ORF8b in type I IFN induction and its disruption of the colocalization of HSP70 with IKKε. Ectopic expression of HSP70 relieved suppression of IFN-ß expression by ORF8b in an IKKε-dependent manner. Enhancement of IFN-ß induction in cells infected with ORF8b-deficient virus was erased when HSP70 was depleted. Taken together, HSP70 chaperone is important for IKKε activation, and MERS-CoV ORF8b suppresses type I IFN expression by competing with IKKε for interaction with HSP70.


Subject(s)
Enzyme Activation/immunology , I-kappa B Kinase/immunology , Interferon Type I/immunology , Middle East Respiratory Syndrome Coronavirus/immunology , Viral Proteins/immunology , Betacoronavirus , COVID-19 , Cell Line , Coronavirus Infections , HSP70 Heat-Shock Proteins/immunology , HSP70 Heat-Shock Proteins/metabolism , Humans , I-kappa B Kinase/metabolism , Interferon Type I/metabolism , Middle East Respiratory Syndrome Coronavirus/metabolism , Pandemics , Pneumonia, Viral , SARS-CoV-2 , Viral Proteins/metabolism
5.
Cell Rep ; 34(7): 108761, 2021 02 16.
Article in English | MEDLINE | ID: covidwho-1062276

ABSTRACT

Coronavirus disease 2019 (COVID-19) is a current global health threat caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Emerging evidence indicates that SARS-CoV-2 elicits a dysregulated immune response and a delayed interferon (IFN) expression in patients, which contribute largely to the viral pathogenesis and development of COVID-19. However, underlying mechanisms remain to be elucidated. Here, we report the activation and repression of the innate immune response by SARS-CoV-2. We show that SARS-CoV-2 RNA activates the RIG-I-MAVS-dependent IFN signaling pathway. We further uncover that ORF9b immediately accumulates and antagonizes the antiviral type I IFN response during SARS-CoV-2 infection on primary human pulmonary alveolar epithelial cells. ORF9b targets the nuclear factor κB (NF-κB) essential modulator NEMO and interrupts its K63-linked polyubiquitination upon viral stimulation, thereby inhibiting the canonical IκB kinase alpha (IKKα)/ß/γ-NF-κB signaling and subsequent IFN production. Our findings thus unveil the innate immunosuppression by ORF9b and provide insights into the host-virus interplay during the early stage of SARS-CoV-2 infection.


Subject(s)
Coronavirus Nucleocapsid Proteins/genetics , I-kappa B Kinase/metabolism , SARS-CoV-2/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Alveolar Epithelial Cells/metabolism , Alveolar Epithelial Cells/virology , COVID-19/immunology , COVID-19/metabolism , Coronavirus Nucleocapsid Proteins/metabolism , HEK293 Cells , Humans , Immunity, Innate/immunology , Interferon Type I/metabolism , Interferons/metabolism , NF-kappa B/metabolism , Phosphoproteins/genetics , Phosphoproteins/metabolism , Primary Cell Culture , Receptors, Retinoic Acid/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Signal Transduction , Ubiquitination
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