Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
1.
PLoS Pathog ; 18(4): e1010464, 2022 04.
Article in English | MEDLINE | ID: covidwho-1789197

ABSTRACT

Interferons establish an antiviral state through the induction of hundreds of interferon-stimulated genes (ISGs). The mechanisms and viral specificities for most ISGs remain incompletely understood. To enable high-throughput interrogation of ISG antiviral functions in pooled genetic screens while mitigating potentially confounding effects of endogenous interferon and antiproliferative/proapoptotic ISG activities, we adapted a CRISPR-activation (CRISPRa) system for inducible ISG expression in isogenic cell lines with and without the capacity to respond to interferons. We used this platform to screen for ISGs that restrict SARS-CoV-2. Results included ISGs previously described to restrict SARS-CoV-2 and novel candidate antiviral factors. We validated a subset of these by complementary CRISPRa and cDNA expression experiments. OAS1, a top-ranked hit across multiple screens, exhibited strong antiviral effects against SARS-CoV-2, which required OAS1 catalytic activity. These studies demonstrate a high-throughput approach to assess antiviral functions within the ISG repertoire, exemplified by identification of multiple SARS-CoV-2 restriction factors.


Subject(s)
2',5'-Oligoadenylate Synthetase , COVID-19 , Interferons , 2',5'-Oligoadenylate Synthetase/genetics , 2',5'-Oligoadenylate Synthetase/metabolism , Antiviral Agents/pharmacology , COVID-19/genetics , Clustered Regularly Interspaced Short Palindromic Repeats , Humans , Interferons/metabolism , SARS-CoV-2/genetics
2.
J Virol ; 95(23): e0125721, 2021 11 09.
Article in English | MEDLINE | ID: covidwho-1410202

ABSTRACT

SARS-CoV-2, the etiological agent of COVID-19, is characterized by a delay in type I interferon (IFN-I)-mediated antiviral defenses alongside robust cytokine production. Here, we investigate the underlying molecular basis for this imbalance and implicate virus-mediated activation of NF-κB in the absence of other canonical IFN-I-related transcription factors. Epigenetic and single-cell transcriptomic analyses show a selective NF-κB signature that was most prominent in infected cells. Disruption of NF-κB signaling through the silencing of the NF-κB transcription factor p65 or p50 resulted in loss of virus replication that was rescued upon reconstitution. These findings could be further corroborated with the use of NF-κB inhibitors, which reduced SARS-CoV-2 replication in vitro. These data suggest that the robust cytokine production in response to SARS-CoV-2, despite a diminished IFN-I response, is the product of a dependency on NF-κB for viral replication. IMPORTANCE The COVID-19 pandemic has caused significant mortality and morbidity around the world. Although effective vaccines have been developed, large parts of the world remain unvaccinated while new SARS-CoV-2 variants keep emerging. Furthermore, despite extensive efforts and large-scale drug screenings, no fully effective antiviral treatment options have been discovered yet. Therefore, it is of the utmost importance to gain a better understanding of essential factors driving SARS-CoV-2 replication to be able to develop novel approaches to target SARS-CoV-2 biology.


Subject(s)
COVID-19/metabolism , Cytokines/metabolism , Interferon Type I/metabolism , SARS-CoV-2 , Transcription Factor RelA/metabolism , Transcriptome , Virus Replication , A549 Cells , Animals , COVID-19/virology , Chlorocebus aethiops , Epigenomics , Gene Expression Regulation , HEK293 Cells , HeLa Cells , Host Microbial Interactions , Humans , Signal Transduction , Single-Cell Analysis , Transcription Factor RelA/antagonists & inhibitors , Transcription Factor RelA/genetics , Transcription Factors/metabolism , Vero Cells
3.
Proc Natl Acad Sci U S A ; 117(45): 28344-28354, 2020 11 10.
Article in English | MEDLINE | ID: covidwho-887237

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic that is a serious global health problem. Evasion of IFN-mediated antiviral signaling is a common defense strategy that pathogenic viruses use to replicate and propagate in their host. In this study, we show that SARS-CoV-2 is able to efficiently block STAT1 and STAT2 nuclear translocation in order to impair transcriptional induction of IFN-stimulated genes (ISGs). Our results demonstrate that the viral accessory protein Orf6 exerts this anti-IFN activity. We found that SARS-CoV-2 Orf6 localizes at the nuclear pore complex (NPC) and directly interacts with Nup98-Rae1 via its C-terminal domain to impair docking of cargo-receptor (karyopherin/importin) complex and disrupt nuclear import. In addition, we show that a methionine-to-arginine substitution at residue 58 impairs Orf6 binding to the Nup98-Rae1 complex and abolishes its IFN antagonistic function. All together our data unravel a mechanism of viral antagonism in which a virus hijacks the Nup98-Rae1 complex to overcome the antiviral action of IFN.


Subject(s)
COVID-19/metabolism , Interferons/metabolism , Nuclear Pore Complex Proteins/metabolism , Nuclear Pore/metabolism , STAT1 Transcription Factor/metabolism , STAT2 Transcription Factor/metabolism , Viral Proteins/metabolism , Active Transport, Cell Nucleus , Animals , Binding Sites , Chlorocebus aethiops , HEK293 Cells , Humans , Nuclear Matrix-Associated Proteins/chemistry , Nuclear Matrix-Associated Proteins/metabolism , Nucleocytoplasmic Transport Proteins/chemistry , Nucleocytoplasmic Transport Proteins/metabolism , Protein Binding , Signal Transduction , Vero Cells
4.
Cell ; 183(4): 982-995.e14, 2020 11 12.
Article in English | MEDLINE | ID: covidwho-756809

ABSTRACT

Initially, children were thought to be spared from disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, a month into the epidemic, a novel multisystem inflammatory syndrome in children (MIS-C) emerged. Herein, we report on the immune profiles of nine MIS-C cases. All MIS-C patients had evidence of prior SARS-CoV-2 exposure, mounting an antibody response with intact neutralization capability. Cytokine profiling identified elevated signatures of inflammation (IL-18 and IL-6), lymphocytic and myeloid chemotaxis and activation (CCL3, CCL4, and CDCP1), and mucosal immune dysregulation (IL-17A, CCL20, and CCL28). Immunophenotyping of peripheral blood revealed reductions of non-classical monocytes, and subsets of NK and T lymphocytes, suggesting extravasation to affected tissues. Finally, profiling the autoantigen reactivity of MIS-C plasma revealed both known disease-associated autoantibodies (anti-La) and novel candidates that recognize endothelial, gastrointestinal, and immune-cell antigens. All patients were treated with anti-IL-6R antibody and/or IVIG, which led to rapid disease resolution.


Subject(s)
Inflammation/pathology , Systemic Inflammatory Response Syndrome/pathology , Adolescent , Antibodies, Viral/blood , Autoantibodies/blood , Betacoronavirus/immunology , Betacoronavirus/isolation & purification , COVID-19 , Chemokine CCL3/metabolism , Child , Child, Preschool , Coronavirus Infections/complications , Coronavirus Infections/pathology , Coronavirus Infections/virology , Female , Humans , Immunity, Humoral , Infant , Infant, Newborn , Inflammation/metabolism , Interleukin-17/metabolism , Interleukin-18/metabolism , Killer Cells, Natural/cytology , Killer Cells, Natural/metabolism , Male , Pandemics , Pneumonia, Viral/complications , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , SARS-CoV-2 , Systemic Inflammatory Response Syndrome/immunology , Systemic Inflammatory Response Syndrome/metabolism , T-Lymphocytes/cytology , T-Lymphocytes/metabolism , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL