Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 22
Filter
1.
Sci Rep ; 12(1): 3890, 2022 03 10.
Article in English | MEDLINE | ID: covidwho-1740469

ABSTRACT

The new outbreak of coronavirus disease 2019 (COVID-19) has infected and caused the death of millions of people worldwide. Intensive efforts are underway around the world to establish effective treatments. Immunoglobulin from immunized animals or plasma from convalescent patients might constitute a specific treatment to guarantee the neutralization of the virus in the early stages of infection, especially in patients with risk factors and a high probability of progressing to severe disease. Worldwide, a few clinical trials using anti-SARS-CoV-2 immunoglobulins from horses immunized with the entire spike protein or fragments of it in the treatment of patients with COVID-19 are underway. Here, we describe the development of an anti-SARS-CoV-2 equine F(ab')2 immunoglobulin using a newly developed SARS-CoV-2 viral antigen that was purified and inactivated by radiation. Cell-based and preclinical assays showed that the F(ab')2 immunoglobulin successfully neutralizes the virus, is safe in animal models, and reduces the severity of the disease in a hamster model of SARS-CoV-2 infection and disease.


Subject(s)
COVID-19/therapy , Immunoglobulins/therapeutic use , Receptors, Immunologic/therapeutic use , SARS-CoV-2/immunology , Animals , Enzyme-Linked Immunosorbent Assay , Female , Horses/immunology , Humans , Immunoglobulins/immunology , Immunoglobulins/isolation & purification , Male , Mesocricetus/immunology , Plasmapheresis/veterinary , Receptors, Immunologic/immunology
2.
Cell Rep ; 38(10): 110434, 2022 03 08.
Article in English | MEDLINE | ID: covidwho-1729611

ABSTRACT

Type I interferons (IFN-I) are essential to establish antiviral innate immunity. Unanchored (or free) polyubiquitin (poly-Ub) has been shown to regulate IFN-I responses. However, few unanchored poly-Ub interactors are known. To identify factors regulated by unanchored poly-Ub in a physiological setting, we developed an approach to isolate unanchored poly-Ub from lung tissue. We identified the RNA helicase DHX16 as a potential pattern recognition receptor (PRR). Silencing of DHX16 in cells and in vivo diminished IFN-I responses against influenza virus. These effects extended to members of other virus families, including Zika and SARS-CoV-2. DHX16-dependent IFN-I production requires RIG-I and unanchored K48-poly-Ub synthesized by the E3-Ub ligase TRIM6. DHX16 recognizes a signal in influenza RNA segments that undergo splicing and requires its RNA helicase motif for direct, high-affinity interactions with specific viral RNAs. Our study establishes DHX16 as a PRR that partners with RIG-I for optimal activation of antiviral immunity requiring unanchored poly-Ub.


Subject(s)
DEAD Box Protein 58 , Interferon Type I , RNA Helicases , RNA, Viral , Receptors, Immunologic , Zika Virus Infection , Zika Virus , COVID-19 , DEAD Box Protein 58/immunology , Humans , Immunity, Innate , Interferon Type I/immunology , RNA Helicases/immunology , Receptors, Immunologic/immunology , SARS-CoV-2 , Tripartite Motif Proteins , Zika Virus/genetics , Zika Virus Infection/immunology
3.
Genes (Basel) ; 13(1)2021 12 23.
Article in English | MEDLINE | ID: covidwho-1580896

ABSTRACT

ADAR1-mediated deamination of adenosines in long double-stranded RNAs plays an important role in modulating the innate immune response. However, recent investigations based on metatranscriptomic samples of COVID-19 patients and SARS-COV-2-infected Vero cells have recovered contrasting findings. Using RNAseq data from time course experiments of infected human cell lines and transcriptome data from Vero cells and clinical samples, we prove that A-to-G changes observed in SARS-COV-2 genomes represent genuine RNA editing events, likely mediated by ADAR1. While the A-to-I editing rate is generally low, changes are distributed along the entire viral genome, are overrepresented in exonic regions, and are (in the majority of cases) nonsynonymous. The impact of RNA editing on virus-host interactions could be relevant to identify potential targets for therapeutic interventions.


Subject(s)
Adenosine Deaminase/genetics , COVID-19/genetics , Genome, Viral , Host-Pathogen Interactions/genetics , RNA Editing , RNA, Viral/genetics , RNA-Binding Proteins/genetics , SARS-CoV-2/genetics , Adenosine/metabolism , Adenosine Deaminase/immunology , Animals , COVID-19/metabolism , COVID-19/virology , Cell Line, Tumor , Chlorocebus aethiops , DEAD Box Protein 58/genetics , DEAD Box Protein 58/immunology , Deamination , Epithelial Cells/immunology , Epithelial Cells/virology , Host-Pathogen Interactions/immunology , Humans , Immunity, Innate , Inosine/metabolism , Interferon-Induced Helicase, IFIH1/genetics , Interferon-Induced Helicase, IFIH1/immunology , Interferon-beta/genetics , Interferon-beta/immunology , RNA, Double-Stranded/genetics , RNA, Double-Stranded/immunology , RNA, Viral/immunology , RNA-Binding Proteins/immunology , Receptors, Immunologic/genetics , Receptors, Immunologic/immunology , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Transcriptome , Vero Cells
4.
J Clin Invest ; 131(21)2021 11 01.
Article in English | MEDLINE | ID: covidwho-1495789

ABSTRACT

To explore how the immune system controls clearance of SARS-CoV-2, we used a single-cell, mass cytometry-based proteomics platform to profile the immune systems of 21 patients who had recovered from SARS-CoV-2 infection without need for admission to an intensive care unit or for mechanical ventilation. We focused on receptors involved in interactions between immune cells and virus-infected cells. We found that the diversity of receptor repertoires on natural killer (NK) cells was negatively correlated with the viral clearance rate. In addition, NK subsets expressing the receptor DNAM1 were increased in patients who more rapidly recovered from infection. Ex vivo functional studies revealed that NK subpopulations with high DNAM1 expression had cytolytic activities in response to target cell stimulation. We also found that SARS-CoV-2 infection induced the expression of CD155 and nectin-4, ligands of DNAM1 and its paired coinhibitory receptor TIGIT, which counterbalanced the cytolytic activities of NK cells. Collectively, our results link the cytolytic immune responses of NK cells to the clearance of SARS-CoV-2 and show that the DNAM1 pathway modulates host-pathogen interactions during SARS-CoV-2 infection.


Subject(s)
COVID-19/immunology , COVID-19/virology , Killer Cells, Natural/immunology , Receptors, Natural Killer Cell/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Animals , Antigens, Differentiation, T-Lymphocyte/immunology , Cell Adhesion Molecules/immunology , Cohort Studies , Cytotoxicity, Immunologic , Female , Heterografts , Host Microbial Interactions/immunology , Humans , Immunophenotyping , In Vitro Techniques , Ligands , Male , Mice , Mice, SCID , Middle Aged , NK Cell Lectin-Like Receptor Subfamily D/immunology , Pandemics , Receptors, Immunologic/immunology , Receptors, Virus/immunology , Viral Load , Young Adult
5.
Acc Chem Res ; 54(21): 4012-4023, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1483069

ABSTRACT

In vitro-transcribed RNAs are emerging as new biologics for therapeutic innovation, as exemplified by their application recently in SARS-CoV-2 vaccinations. RNAs prepared by in vitro transcription (IVT) allow transient expression of proteins of interest, conferring safety over DNA- or virus-mediated gene delivery systems. However, in vitro-transcribed RNAs should be used with caution because of their immunogenicity, which is in part triggered by double-stranded RNA (dsRNA) byproducts during IVT. Cellular innate immune response to dsRNA byproducts can lead to undesirable consequences, including suppression of protein synthesis and cell death, which in turn can detrimentally impact the efficacy of mRNA therapy. Thus, it is critical to understand the nature of IVT byproducts and the mechanisms by which they trigger innate immune responses.Our lab has been investigating the mechanisms by which the innate immune system discriminates between "self" and "nonself" RNA, with the focus on the cytoplasmic dsRNA receptors retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated 5 (MDA5). We have biochemically and structurally characterized critical events involving RNA discrimination and signal transduction by RIG-I or MDA5. We have used in vitro-transcribed RNAs as tools to investigate RNA specificity of RIG-I and MDA5, which required optimization of the IVT reaction and purification processes to eliminate the effect of IVT byproducts. In this Account, we summarize our current understanding of RIG-I and MDA5 and IVT reactions and propose future directions for improving IVT as a method to generate both research tools and therapeutics. Other critical proteins in cellular innate immune response to dsRNAs are also discussed. We arrange the contents in the following order: (i) innate immunity sensors for nonself RNA, including the RIG-I-like receptors (RLRs) in the cytosol and the toll-like receptors (TLRs) in the endosome, as well as cytoplasmic dsRNA-responding proteins, including protein kinase R (PKR) and 2',5'-oligoadenylate synthetases (OASes), illustrating the feature of protein-RNA binding and its consequences; (ii) the immunogenicity of IVT byproducts, specifically the generation of dsRNA molecules during IVT; and (iii) methods to reduce IVT RNA immunogenicity, including optimizations of RNA polymerases, reagents, and experimental conditions during IVT and subsequent purification.


Subject(s)
RNA, Viral/immunology , SARS-CoV-2/genetics , DEAD Box Protein 58/genetics , DEAD Box Protein 58/immunology , Humans , Immunity, Innate/genetics , Immunity, Innate/immunology , Interferon-Induced Helicase, IFIH1/genetics , Interferon-Induced Helicase, IFIH1/immunology , RNA, Viral/genetics , Receptors, Immunologic/genetics , Receptors, Immunologic/immunology , SARS-CoV-2/immunology
6.
J Med Virol ; 93(9): 5376-5389, 2021 09.
Article in English | MEDLINE | ID: covidwho-1363676

ABSTRACT

The suppression of types I and III interferon (IFN) responses by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contributes to the pathogenesis of coronavirus disease 2019 (COVID-19). The strategy used by SARS-CoV-2 to evade antiviral immunity needs further investigation. Here, we reported that SARS-CoV-2 ORF9b inhibited types I and III IFN production by targeting multiple molecules of innate antiviral signaling pathways. SARS-CoV-2 ORF9b impaired the induction of types I and III IFNs by Sendai virus and poly (I:C). SARS-CoV-2 ORF9b inhibited the activation of types I and III IFNs induced by the components of cytosolic dsRNA-sensing pathways of RIG-I/MDA5-MAVS signaling, including RIG-I, MDA-5, MAVS, TBK1, and IKKε, rather than IRF3-5D, which is the active form of IRF3. SARS-CoV-2 ORF9b also suppressed the induction of types I and III IFNs by TRIF and STING, which are the adaptor protein of the endosome RNA-sensing pathway of TLR3-TRIF signaling and the adaptor protein of the cytosolic DNA-sensing pathway of cGAS-STING signaling, respectively. A mechanistic analysis revealed that the SARS-CoV-2 ORF9b protein interacted with RIG-I, MDA-5, MAVS, TRIF, STING, and TBK1 and impeded the phosphorylation and nuclear translocation of IRF3. In addition, SARS-CoV-2 ORF9b facilitated the replication of the vesicular stomatitis virus. Therefore, the results showed that SARS-CoV-2 ORF9b negatively regulates antiviral immunity and thus facilitates viral replication. This study contributes to our understanding of the molecular mechanism through which SARS-CoV-2 impairs antiviral immunity and provides an essential clue to the pathogenesis of COVID-19.


Subject(s)
DEAD Box Protein 58/immunology , Immune Evasion/genetics , Interferons/immunology , Nucleotidyltransferases/immunology , Receptors, Immunologic/immunology , SARS-CoV-2/immunology , Toll-Like Receptor 3/immunology , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/immunology , Adaptor Proteins, Vesicular Transport/genetics , Adaptor Proteins, Vesicular Transport/immunology , Animals , Chlorocebus aethiops , Coronavirus Nucleocapsid Proteins/genetics , Coronavirus Nucleocapsid Proteins/immunology , DEAD Box Protein 58/genetics , Gene Expression Regulation , HEK293 Cells , HeLa Cells , Humans , I-kappa B Kinase/genetics , I-kappa B Kinase/immunology , Immunity, Innate , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/immunology , Interferon-Induced Helicase, IFIH1/genetics , Interferon-Induced Helicase, IFIH1/immunology , Interferons/genetics , Membrane Proteins/genetics , Membrane Proteins/immunology , Nucleotidyltransferases/genetics , Phosphoproteins/genetics , Phosphoproteins/immunology , Plasmids/chemistry , Plasmids/metabolism , /immunology , Receptors, Immunologic/genetics , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Signal Transduction/genetics , Signal Transduction/immunology , Toll-Like Receptor 3/genetics , Transfection , Vero Cells , Virus Replication/immunology
7.
Cell Chem Biol ; 29(2): 239-248.e4, 2022 02 17.
Article in English | MEDLINE | ID: covidwho-1347527

ABSTRACT

Triggering receptor expressed on myeloid cells-2 (TREM2) is a cell surface receptor on macrophages and microglia that senses and responds to disease-associated signals to regulate the phenotype of these innate immune cells. The TREM2 signaling pathway has been implicated in a variety of diseases ranging from neurodegeneration in the central nervous system to metabolic disease in the periphery. Here, we report that TREM2 is a thyroid hormone-regulated gene and its expression in macrophages and microglia is stimulated by thyroid hormone and synthetic thyroid hormone agonists (thyromimetics). Our findings report the endocrine regulation of TREM2 by thyroid hormone, and provide a unique opportunity to drug the TREM2 signaling pathway with orally active small-molecule therapeutic agents.


Subject(s)
Acetates/pharmacology , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Membrane Glycoproteins/genetics , Microglia/drug effects , Phenols/pharmacology , Receptors, Immunologic/genetics , Retinoid X Receptors/genetics , Thyroid Hormones/pharmacology , Acetates/chemical synthesis , Animals , Binding Sites , Brain/drug effects , Brain/immunology , Brain/pathology , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/pathology , Gene Expression Regulation , Humans , Immunity, Innate , Macrophages/drug effects , Macrophages/immunology , Macrophages/pathology , Membrane Glycoproteins/antagonists & inhibitors , Membrane Glycoproteins/immunology , Mice , Mice, Inbred C57BL , Microglia/immunology , Microglia/pathology , Models, Molecular , Phenols/chemical synthesis , Phenoxyacetates/pharmacology , Promoter Regions, Genetic , Protein Binding , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , RNA, Messenger/antagonists & inhibitors , RNA, Messenger/genetics , RNA, Messenger/immunology , Receptors, Immunologic/antagonists & inhibitors , Receptors, Immunologic/immunology , Response Elements , Retinoid X Receptors/chemistry , Retinoid X Receptors/metabolism , Signal Transduction
8.
JCI Insight ; 6(13)2021 06 18.
Article in English | MEDLINE | ID: covidwho-1346128

ABSTRACT

We explored the potential link between chronic inflammatory arthritis and COVID-19 pathogenic and resolving macrophage pathways and their role in COVID-19 pathogenesis. We found that bronchoalveolar lavage fluid (BALF) macrophage clusters FCN1+ and FCN1+SPP1+ predominant in severe COVID-19 were transcriptionally related to synovial tissue macrophage (STM) clusters CD48hiS100A12+ and CD48+SPP1+ that drive rheumatoid arthritis (RA) synovitis. BALF macrophage cluster FABP4+ predominant in healthy lung was transcriptionally related to STM cluster TREM2+ that governs resolution of synovitis in RA remission. Plasma concentrations of SPP1 and S100A12 (key products of macrophage clusters shared with active RA) were high in severe COVID-19 and predicted the need for Intensive Care Unit transfer, and they remained high in the post-COVID-19 stage. High plasma levels of SPP1 were unique to severe COVID-19 when compared with other causes of severe pneumonia, and IHC localized SPP1+ macrophages in the alveoli of COVID-19 lung. Investigation into SPP1 mechanisms of action revealed that it drives proinflammatory activation of CD14+ monocytes and development of PD-L1+ neutrophils, both hallmarks of severe COVID-19. In summary, COVID-19 pneumonitis appears driven by similar pathogenic myeloid cell pathways as those in RA, and their mediators such as SPP1 might be an upstream activator of the aberrant innate response in severe COVID-19 and predictive of disease trajectory including post-COVID-19 pathology.


Subject(s)
Arthritis, Rheumatoid/immunology , COVID-19/immunology , Monocytes/immunology , Neutrophils/immunology , Osteopontin/immunology , Arthritis, Rheumatoid/metabolism , B7-H1 Antigen/immunology , Bronchoalveolar Lavage Fluid/immunology , CD48 Antigen/immunology , COVID-19/chemically induced , COVID-19/metabolism , Fatty Acid-Binding Proteins/immunology , Humans , Lectins/immunology , Lipopolysaccharide Receptors/immunology , Lipopolysaccharide Receptors/metabolism , Lung/diagnostic imaging , Lung/immunology , Lung/metabolism , Lung/pathology , Macrophages/immunology , Macrophages/metabolism , Membrane Glycoproteins/immunology , Monocytes/metabolism , Neutrophils/metabolism , Osteopontin/blood , Receptor Protein-Tyrosine Kinases/metabolism , Receptors, Immunologic/immunology , S100A12 Protein/immunology , S100A12 Protein/metabolism , Synovial Membrane/immunology , Tomography, X-Ray Computed
9.
Viruses ; 13(8)2021 07 23.
Article in English | MEDLINE | ID: covidwho-1325791

ABSTRACT

A weak production of INF-ß along with an exacerbated release of pro-inflammatory cytokines have been reported during infection by the novel SARS-CoV-2 virus. SARS-CoV-2 encodes several proteins able to counteract the host immune system, which is believed to be one of the most important features contributing to the viral pathogenesis and development of a severe clinical picture. Previous reports have demonstrated that SARS-CoV-2 N protein, along with some non-structural and accessory proteins, efficiently suppresses INF-ß production by interacting with RIG-I, an important pattern recognition receptor (PRR) involved in the recognition of pathogen-derived molecules. In the present study, we better characterized the mechanism by which the SARS-CoV-2 N counteracts INF-ß secretion and affects RIG-I signaling pathways. In detail, when the N protein was ectopically expressed, we noted a marked decrease in TRIM25-mediated RIG-I activation. The capability of the N protein to bind to, and probably mask, TRIM25 could be the consequence of its antagonistic activity. Furthermore, this interaction occurred at the SPRY domain of TRIM25, harboring the RNA-binding activity necessary for TRIM25 self-activation. Here, we describe new findings regarding the interplay between SARS-CoV-2 and the IFN system, filling some gaps for a better understanding of the molecular mechanisms affecting the innate immune response in COVID-19.


Subject(s)
COVID-19/immunology , Coronavirus Nucleocapsid Proteins/immunology , DEAD Box Protein 58/immunology , Receptors, Immunologic/immunology , SARS-CoV-2/immunology , Transcription Factors/immunology , Tripartite Motif Proteins/immunology , Ubiquitin-Protein Ligases/immunology , COVID-19/genetics , COVID-19/virology , Coronavirus Nucleocapsid Proteins/genetics , DEAD Box Protein 58/genetics , Gene Expression Regulation , Host-Pathogen Interactions , Humans , Immunity, Innate , Interferon-beta/genetics , Interferon-beta/immunology , Promoter Regions, Genetic , Receptors, Immunologic/genetics , SARS-CoV-2/genetics , Signal Transduction , Transcription Factors/genetics , Tripartite Motif Proteins/genetics , Ubiquitin-Protein Ligases/genetics
10.
Front Immunol ; 12: 688758, 2021.
Article in English | MEDLINE | ID: covidwho-1304592

ABSTRACT

Coronaviruses (CoVs) are a known global threat, and most recently the ongoing COVID-19 pandemic has claimed more than 2 million human lives. Delays and interference with IFN responses are closely associated with the severity of disease caused by CoV infection. As the most abundant viral protein in infected cells just after the entry step, the CoV nucleocapsid (N) protein likely plays a key role in IFN interruption. We have conducted a comprehensive comparative analysis and report herein that the N proteins of representative human and animal CoVs from four different genera [swine acute diarrhea syndrome CoV (SADS-CoV), porcine epidemic diarrhea virus (PEDV), severe acute respiratory syndrome CoV (SARS-CoV), SARS-CoV-2, Middle East respiratory syndrome CoV (MERS-CoV), infectious bronchitis virus (IBV) and porcine deltacoronavirus (PDCoV)] suppress IFN responses by multiple strategies. In particular, we found that the N protein of SADS-CoV interacted with RIG-I independent of its RNA binding activity, mediating K27-, K48- and K63-linked ubiquitination of RIG-I and its subsequent proteasome-dependent degradation, thus inhibiting the host IFN response. These data provide insight into the interaction between CoVs and host, and offer new clues for the development of therapies against these important viruses.


Subject(s)
Coronavirus Nucleocapsid Proteins/genetics , Coronavirus Nucleocapsid Proteins/immunology , DEAD Box Protein 58/metabolism , Interferons/antagonists & inhibitors , Interferons/immunology , Receptors, Immunologic/metabolism , Amino Acid Sequence/genetics , Animals , COVID-19/pathology , DEAD Box Protein 58/immunology , Deltacoronavirus/genetics , Deltacoronavirus/immunology , Humans , Infectious bronchitis virus/genetics , Infectious bronchitis virus/immunology , Interferon Regulatory Factor-3/metabolism , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/immunology , Phosphorylation , Porcine epidemic diarrhea virus/genetics , Porcine epidemic diarrhea virus/immunology , Receptors, Immunologic/immunology , SARS Virus/genetics , SARS Virus/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Swine , Ubiquitination/physiology
11.
Front Immunol ; 12: 688758, 2021.
Article in English | MEDLINE | ID: covidwho-1295641

ABSTRACT

Coronaviruses (CoVs) are a known global threat, and most recently the ongoing COVID-19 pandemic has claimed more than 2 million human lives. Delays and interference with IFN responses are closely associated with the severity of disease caused by CoV infection. As the most abundant viral protein in infected cells just after the entry step, the CoV nucleocapsid (N) protein likely plays a key role in IFN interruption. We have conducted a comprehensive comparative analysis and report herein that the N proteins of representative human and animal CoVs from four different genera [swine acute diarrhea syndrome CoV (SADS-CoV), porcine epidemic diarrhea virus (PEDV), severe acute respiratory syndrome CoV (SARS-CoV), SARS-CoV-2, Middle East respiratory syndrome CoV (MERS-CoV), infectious bronchitis virus (IBV) and porcine deltacoronavirus (PDCoV)] suppress IFN responses by multiple strategies. In particular, we found that the N protein of SADS-CoV interacted with RIG-I independent of its RNA binding activity, mediating K27-, K48- and K63-linked ubiquitination of RIG-I and its subsequent proteasome-dependent degradation, thus inhibiting the host IFN response. These data provide insight into the interaction between CoVs and host, and offer new clues for the development of therapies against these important viruses.


Subject(s)
Coronavirus Nucleocapsid Proteins/genetics , Coronavirus Nucleocapsid Proteins/immunology , DEAD Box Protein 58/metabolism , Interferons/antagonists & inhibitors , Interferons/immunology , Receptors, Immunologic/metabolism , Amino Acid Sequence/genetics , Animals , COVID-19/pathology , DEAD Box Protein 58/immunology , Deltacoronavirus/genetics , Deltacoronavirus/immunology , Humans , Infectious bronchitis virus/genetics , Infectious bronchitis virus/immunology , Interferon Regulatory Factor-3/metabolism , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/immunology , Phosphorylation , Porcine epidemic diarrhea virus/genetics , Porcine epidemic diarrhea virus/immunology , Receptors, Immunologic/immunology , SARS Virus/genetics , SARS Virus/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Swine , Ubiquitination/physiology
12.
Curr Opin Virol ; 49: 176-182, 2021 08.
Article in English | MEDLINE | ID: covidwho-1275242

ABSTRACT

NK cells and diverse populations of unconventional T cells, such as MAIT cells, γδ T cells, invariant NKT cells, and DNTÉ‘ß cells are important early effector lymphocytes. While some of these cells, such as NK cell and MAIT cells, have well-established roles in antiviral defense, the function of other populations remains more elusive. Here, we summarize and discuss current knowledge on NK cell and unconventional T cell responses to SARS-CoV-2 infection. Also covered is the role of these cells in the pathogenesis of severe COVID-19. Understanding the early, both systemic and local (lung), effector lymphocyte response in this novel disease will likely aid ongoing efforts to combat the pandemic.


Subject(s)
COVID-19/immunology , Killer Cells, Natural/immunology , T-Lymphocytes/immunology , COVID-19/pathology , Cytokines/immunology , Humans , Lung/immunology , Lung/pathology , Mucosal-Associated Invariant T Cells/immunology , Natural Killer T-Cells/immunology , Receptors, Immunologic/immunology , SARS-CoV-2/immunology
13.
EMBO J ; 40(15): e107826, 2021 08 02.
Article in English | MEDLINE | ID: covidwho-1261483

ABSTRACT

SARS-CoV-2 infection causes broad-spectrum immunopathological disease, exacerbated by inflammatory co-morbidities. A better understanding of mechanisms underpinning virus-associated inflammation is required to develop effective therapeutics. Here, we discover that SARS-CoV-2 replicates rapidly in lung epithelial cells despite triggering a robust innate immune response through the activation of cytoplasmic RNA sensors RIG-I and MDA5. The inflammatory mediators produced during epithelial cell infection can stimulate primary human macrophages to enhance cytokine production and drive cellular activation. Critically, this can be limited by abrogating RNA sensing or by inhibiting downstream signalling pathways. SARS-CoV-2 further exacerbates the local inflammatory environment when macrophages or epithelial cells are primed with exogenous inflammatory stimuli. We propose that RNA sensing of SARS-CoV-2 in lung epithelium is a key driver of inflammation, the extent of which is influenced by the inflammatory state of the local environment, and that specific inhibition of innate immune pathways may beneficially mitigate inflammation-associated COVID-19.


Subject(s)
COVID-19/immunology , DEAD Box Protein 58/immunology , Epithelial Cells/immunology , Interferon-Induced Helicase, IFIH1/immunology , Macrophages/immunology , RNA, Viral/immunology , Receptors, Immunologic/immunology , SARS-CoV-2 , COVID-19/genetics , COVID-19/virology , Cell Line , Cytokines/genetics , Cytokines/immunology , Epithelial Cells/virology , Host-Pathogen Interactions , Humans , Immunity, Innate , Inflammation/genetics , Inflammation/immunology , Inflammation/virology , Janus Kinases/immunology , Lung/cytology , Lung/immunology , Lung/virology , Macrophage Activation , NF-kappa B/immunology , Respiratory Mucosa/cytology , Respiratory Mucosa/immunology , Respiratory Mucosa/virology , SARS-CoV-2/genetics , SARS-CoV-2/physiology , STAT Transcription Factors/immunology , Virus Replication
14.
Front Immunol ; 12: 593595, 2021.
Article in English | MEDLINE | ID: covidwho-1229174

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is a global health threat with the potential to cause severe disease manifestations in the lungs. Although COVID-19 has been extensively characterized clinically, the factors distinguishing SARS-CoV-2 from other respiratory viruses are unknown. Here, we compared the clinical, histopathological, and immunological characteristics of patients with COVID-19 and pandemic influenza A(H1N1). We observed a higher frequency of respiratory symptoms, increased tissue injury markers, and a histological pattern of alveolar pneumonia in pandemic influenza A(H1N1) patients. Conversely, dry cough, gastrointestinal symptoms and interstitial lung pathology were observed in COVID-19 cases. Pandemic influenza A(H1N1) was characterized by higher levels of IL-1RA, TNF-α, CCL3, G-CSF, APRIL, sTNF-R1, sTNF-R2, sCD30, and sCD163. Meanwhile, COVID-19 displayed an immune profile distinguished by increased Th1 (IL-12, IFN-γ) and Th2 (IL-4, IL-5, IL-10, IL-13) cytokine levels, along with IL-1ß, IL-6, CCL11, VEGF, TWEAK, TSLP, MMP-1, and MMP-3. Our data suggest that SARS-CoV-2 induces a dysbalanced polyfunctional inflammatory response that is different from the immune response against pandemic influenza A(H1N1). Furthermore, we demonstrated the diagnostic potential of some clinical and immune factors to differentiate both diseases. These findings might be relevant for the ongoing and future influenza seasons in the Northern Hemisphere, which are historically unique due to their convergence with the COVID-19 pandemic.


Subject(s)
COVID-19 , Cytokines , Influenza A Virus, H1N1 Subtype , Influenza, Human , Matrix Metalloproteinase 1 , Matrix Metalloproteinase 3 , Receptors, Immunologic , Adult , Aged , COVID-19/blood , COVID-19/epidemiology , COVID-19/immunology , Cytokines/blood , Cytokines/immunology , Female , Humans , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H1N1 Subtype/metabolism , Influenza, Human/blood , Influenza, Human/epidemiology , Influenza, Human/immunology , Male , Matrix Metalloproteinase 1/blood , Matrix Metalloproteinase 1/immunology , Matrix Metalloproteinase 3/blood , Matrix Metalloproteinase 3/immunology , Middle Aged , Prospective Studies , Receptors, Immunologic/blood , Receptors, Immunologic/immunology , Th1 Cells/immunology , Th2 Cells/immunology
15.
Nat Immunol ; 22(7): 820-828, 2021 07.
Article in English | MEDLINE | ID: covidwho-1225511

ABSTRACT

Efficient immune responses against viral infection are determined by sufficient activation of nucleic acid sensor-mediated innate immunity1,2. Coronavirus disease 2019, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains an ongoing global pandemic. It is an urgent challenge to clarify the innate recognition mechanism to control this virus. Here we show that retinoic acid-inducible gene-I (RIG-I) sufficiently restrains SARS-CoV-2 replication in human lung cells in a type I/III interferon (IFN)-independent manner. RIG-I recognizes the 3' untranslated region of the SARS-CoV-2 RNA genome via the helicase domains, but not the C-terminal domain. This new mode of RIG-I recognition does not stimulate its ATPase, thereby aborting the activation of the conventional mitochondrial antiviral-signaling protein-dependent pathways, which is in accordance with lack of cytokine induction. Nevertheless, the interaction of RIG-I with the viral genome directly abrogates viral RNA-dependent RNA polymerase mediation of the first step of replication. Consistently, genetic ablation of RIG-I allows lung cells to produce viral particles that expressed the viral spike protein. By contrast, the anti-SARS-CoV-2 activity was restored by all-trans retinoic acid treatment through upregulation of RIG-I protein expression in primary lung cells derived from patients with chronic obstructive pulmonary disease. Thus, our findings demonstrate the distinctive role of RIG-I as a restraining factor in the early phase of SARS-CoV-2 infection in human lung cells.


Subject(s)
COVID-19/immunology , DEAD Box Protein 58/immunology , Lung/immunology , Receptors, Immunologic/immunology , SARS-CoV-2/immunology , A549 Cells , Animals , Cell Line , Cell Line, Tumor , Chlorocebus aethiops , Dogs , HEK293 Cells , Humans , Interferon Type I/immunology , Interferons/immunology , Lung/virology , Madin Darby Canine Kidney Cells , Pulmonary Disease, Chronic Obstructive/immunology , RNA-Dependent RNA Polymerase/immunology , Sf9 Cells , Signal Transduction/immunology , Vero Cells , Viral Proteins/immunology
16.
J Med Virol ; 93(9): 5376-5389, 2021 09.
Article in English | MEDLINE | ID: covidwho-1206842

ABSTRACT

The suppression of types I and III interferon (IFN) responses by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contributes to the pathogenesis of coronavirus disease 2019 (COVID-19). The strategy used by SARS-CoV-2 to evade antiviral immunity needs further investigation. Here, we reported that SARS-CoV-2 ORF9b inhibited types I and III IFN production by targeting multiple molecules of innate antiviral signaling pathways. SARS-CoV-2 ORF9b impaired the induction of types I and III IFNs by Sendai virus and poly (I:C). SARS-CoV-2 ORF9b inhibited the activation of types I and III IFNs induced by the components of cytosolic dsRNA-sensing pathways of RIG-I/MDA5-MAVS signaling, including RIG-I, MDA-5, MAVS, TBK1, and IKKε, rather than IRF3-5D, which is the active form of IRF3. SARS-CoV-2 ORF9b also suppressed the induction of types I and III IFNs by TRIF and STING, which are the adaptor protein of the endosome RNA-sensing pathway of TLR3-TRIF signaling and the adaptor protein of the cytosolic DNA-sensing pathway of cGAS-STING signaling, respectively. A mechanistic analysis revealed that the SARS-CoV-2 ORF9b protein interacted with RIG-I, MDA-5, MAVS, TRIF, STING, and TBK1 and impeded the phosphorylation and nuclear translocation of IRF3. In addition, SARS-CoV-2 ORF9b facilitated the replication of the vesicular stomatitis virus. Therefore, the results showed that SARS-CoV-2 ORF9b negatively regulates antiviral immunity and thus facilitates viral replication. This study contributes to our understanding of the molecular mechanism through which SARS-CoV-2 impairs antiviral immunity and provides an essential clue to the pathogenesis of COVID-19.


Subject(s)
DEAD Box Protein 58/immunology , Immune Evasion/genetics , Interferons/immunology , Nucleotidyltransferases/immunology , Receptors, Immunologic/immunology , SARS-CoV-2/immunology , Toll-Like Receptor 3/immunology , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/immunology , Adaptor Proteins, Vesicular Transport/genetics , Adaptor Proteins, Vesicular Transport/immunology , Animals , Chlorocebus aethiops , Coronavirus Nucleocapsid Proteins/genetics , Coronavirus Nucleocapsid Proteins/immunology , DEAD Box Protein 58/genetics , Gene Expression Regulation , HEK293 Cells , HeLa Cells , Humans , I-kappa B Kinase/genetics , I-kappa B Kinase/immunology , Immunity, Innate , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/immunology , Interferon-Induced Helicase, IFIH1/genetics , Interferon-Induced Helicase, IFIH1/immunology , Interferons/genetics , Membrane Proteins/genetics , Membrane Proteins/immunology , Nucleotidyltransferases/genetics , Phosphoproteins/genetics , Phosphoproteins/immunology , Plasmids/chemistry , Plasmids/metabolism , /immunology , Receptors, Immunologic/genetics , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Signal Transduction/genetics , Signal Transduction/immunology , Toll-Like Receptor 3/genetics , Transfection , Vero Cells , Virus Replication/immunology
17.
Virus Res ; 299: 198347, 2021 07 02.
Article in English | MEDLINE | ID: covidwho-1096265

ABSTRACT

BACKGROUND: There is a marked discrepancy between SARS-CoV-2 seroprevalence and COVID-19 cases and deaths in Africa. MAIN: SARS-CoV-2 stimulates humoral and cellular immunity systems, as well as mitogen-activated protein kinase (MAPK) and nuclear NF-kB signalling pathways, which regulate inflammatory gene expression and immune cell differentiation. The result is pro-inflammatory cytokines release, hyperinflammatory condition, and cytokine storm, which provoke severe lung alterations that can lead to multi-organ failure in COVID-19. Multiple genetic and immunologic factors may contribute to the severity of COVID-19 in African individuals when compared to the rest of the global population. In this article, the role of malaria, NF-kB and MAPK pathways, caspase-12 expression, high level of LAIR-1-containing antibodies, and differential glycophorins (GYPA/B) expression in COVID-19 are discussed. CONCLUSION: Understanding pathophysiological mechanisms can help identify target points for drugs and vaccines development against COVID-19. To our knowledge, this is the first study that explores this link and proposes a biological and molecular answer to the epidemiologic discrepancy in COVID-19 in Africa.


Subject(s)
COVID-19/genetics , COVID-19/immunology , Malaria/genetics , Malaria/immunology , Africa/epidemiology , COVID-19/epidemiology , COVID-19/ethnology , Caspase 12/genetics , Caspase 12/immunology , Glycophorins/genetics , Glycophorins/immunology , Humans , Malaria/epidemiology , Malaria/ethnology , NF-kappa B/immunology , Receptors, Immunologic/genetics , Receptors, Immunologic/immunology , SARS-CoV-2/immunology , Signal Transduction/immunology
18.
Cell Mol Immunol ; 18(3): 539-555, 2021 03.
Article in English | MEDLINE | ID: covidwho-1065857

ABSTRACT

Retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) are RNA sensor molecules that play essential roles in innate antiviral immunity. Among the three RLRs encoded by the human genome, RIG-I and melanoma differentiation-associated gene 5, which contain N-terminal caspase recruitment domains, are activated upon the detection of viral RNAs in the cytoplasm of virus-infected cells. Activated RLRs induce downstream signaling via their interactions with mitochondrial antiviral signaling proteins and activate the production of type I and III interferons and inflammatory cytokines. Recent studies have shown that RLR-mediated signaling is regulated by interactions with endogenous RNAs and host proteins, such as those involved in stress responses and posttranslational modifications. Since RLR-mediated cytokine production is also involved in the regulation of acquired immunity, the deregulation of RLR-mediated signaling is associated with autoimmune and autoinflammatory disorders. Moreover, RLR-mediated signaling might be involved in the aberrant cytokine production observed in coronavirus disease 2019. Since the discovery of RLRs in 2004, significant progress has been made in understanding the mechanisms underlying the activation and regulation of RLR-mediated signaling pathways. Here, we review the recent advances in the understanding of regulated RNA recognition and signal activation by RLRs, focusing on the interactions between various host and viral factors.


Subject(s)
DEAD Box Protein 58/immunology , Mitochondria/immunology , Receptors, Immunologic/immunology , Signal Transduction , Virus Diseases/immunology , Viruses/immunology , Animals , Humans , Immunologic Factors , Interferon Type I/immunology , Interferons/immunology
19.
Antiviral Res ; 182: 104868, 2020 10.
Article in English | MEDLINE | ID: covidwho-909531

ABSTRACT

COVID-19, which is caused by the emerging human coronavirus SARS-CoV-2, has become a global pandemic that poses a serious threat to human health. To date, no vaccines or specific antiviral drugs have been approved for the treatment of this disease in clinic. Herein, therapeutic antibodies for SARS-CoV-2 were obtained from hyperimmune equine plasma. First, a recombinant SARS-CoV-2 spike protein receptor-binding domain (RBD) was obtained in gram-level quantities through high-cell density fermentation of Chinese hamster ovary cells. Then, the binding of the RBD to the SARS-CoV-2 receptor, human angiotensin-converting enzyme 2, was verified by several biochemical methods. The efficacy of the RBD in triggering antibody response in vivo was subsequently tested in both mice and equines, and the results showed that the RBD triggered high-titer neutralizing antibody production in vivo. Immunoglobulin F(ab')2 fragments were prepared from equine antisera via removal of the Fc region from the immunoglobulins. Finally, a neutralization test with live virus demonstrated that RBD-specific F(ab')2 inhibited SARS-CoV-2 with an EC50 of 0.07 µg/ml and an EC80 of 0.18 µg/ml, showing a potent inhibitory effect on SARS-CoV-2. These results highlight RBD-specific equine immunoglobulin F(ab')2 fragment as a candidate for the treatment of SARS-CoV-2.


Subject(s)
Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Coronavirus Infections/therapy , Coronavirus Infections/virology , Pneumonia, Viral/therapy , Pneumonia, Viral/virology , Receptors, Immunologic/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Viral/immunology , COVID-19 , Chlorocebus aethiops , Female , HeLa Cells , Humans , Mice, Inbred BALB C , Neutralization Tests , Pandemics , Protein Binding , SARS-CoV-2 , Vero Cells
20.
Eur J Immunol ; 50(12): 2013-2024, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-880266

ABSTRACT

The characterization of cell-mediated and humoral adaptive immune responses to SARS-CoV-2 is fundamental to understand COVID-19 progression and the development of immunological memory to the virus. In this study, we detected T-cells reactive to SARS-CoV-2 proteins M, S, and N, as well as serum virus-specific IgM, IgA, IgG, in nearly all SARS-CoV-2 infected individuals, but not in healthy donors. Virus-reactive T cells exhibited signs of in vivo activation, as suggested by the surface expression of immune-checkpoint molecules PD1 and TIGIT. Of note, we detected antigen-specific adaptive immune response both in asymptomatic and symptomatic SARS-CoV-2 infected subjects. More importantly, symptomatic patients displayed a significantly higher magnitude of both cell-mediated and humoral adaptive immune response to the virus, as compared to asymptomatic individuals. These findings suggest that an uncontrolled adaptive immune response contribute to the development of the life-threatening inflammatory phase of the disease. Finally, this study might open the way to develop effective vaccination strategies.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , Carrier State/immunology , Immunity, Humoral , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Adult , Carrier State/virology , Female , Humans , Programmed Cell Death 1 Receptor/immunology , Receptors, Immunologic/immunology , Viral Proteins/immunology
SELECTION OF CITATIONS
SEARCH DETAIL