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1.
Aging Cell ; 21(6): e13646, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-1883166

ABSTRACT

Older age and underlying conditions such as diabetes/obesity or immunosuppression are leading host risk factors for developing severe complications from COVID-19 infection. The pathogenesis of COVID-19-related cytokine storm, tissue damage, and fibrosis may be interconnected with fundamental aging processes, including dysregulated immune responses and cellular senescence. Here, we examined effects of key cytokines linked to cellular senescence on expression of SARS-CoV-2 viral entry receptors. We found exposure of human umbilical vein endothelial cells (HUVECs) to the inflammatory cytokines, TNF-α + IFN-γ or a cocktail of TNF-α + IFN-γ + IL-6, increased expression of ACE2/DPP4, accentuated the pro-inflammatory senescence-associated secretory phenotype (SASP), and decreased cellular proliferative capacity, consistent with progression towards a cellular senescence-like state. IL-6 by itself failed to induce substantial effects on viral entry receptors or SASP-related genes, while synergy between TNF-α and IFN-γ initiated a positive feedback loop via hyper-activation of the JAK/STAT1 pathway, causing SASP amplification. Breaking the interactive loop between senescence and cytokine secretion with JAK inhibitor ruxolitinib or antiviral drug remdesivir prevented hyper-inflammation, normalized SARS-CoV-2 entry receptor expression, and restored HUVECs proliferative capacity. This loop appears to underlie cytokine-mediated viral entry receptor activation and links with senescence and hyper-inflammation.


Subject(s)
COVID-19 , SARS-CoV-2 , Cytokines/metabolism , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Inflammation , Interferon-gamma/metabolism , Interferon-gamma/pharmacology , Interleukin-6/metabolism , Receptors, Virus/metabolism , STAT1 Transcription Factor/metabolism , Tumor Necrosis Factor-alpha/metabolism , Tumor Necrosis Factor-alpha/pharmacology
2.
J Virol ; 96(9): e0040022, 2022 05 11.
Article in English | MEDLINE | ID: covidwho-1807320

ABSTRACT

Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic enteric coronavirus that causes high mortality in piglets. Interferon (IFN) responses are the primary defense mechanism against viral infection; however, viruses always evolve elaborate strategies to antagonize the antiviral action of IFN. Previous study showed that PEDV nonstructural protein 7 (nsp7), a component of the viral replicase polyprotein, can antagonize ploy(I:C)-induced type I IFN production. Here, we found that PEDV nsp7 also antagonized IFN-α-induced JAK-STAT signaling and the production of IFN-stimulated genes. PEDV nsp7 did not affect the protein and phosphorylation levels of JAK1, Tyk2, STAT1, and STAT2 or the formation of the interferon-stimulated gene factor 3 (ISGF3) complex. However, PEDV nsp7 prevented the nuclear translocation of STAT1 and STAT2. Mechanistically, PEDV nsp7 interacted with the DNA binding domain of STAT1/STAT2, which sequestered the interaction between karyopherin α1 (KPNA1) and STAT1, thereby blocking the nuclear transport of ISGF3. Collectively, these data reveal a new mechanism developed by PEDV to inhibit type I IFN signaling pathway. IMPORTANCE In recent years, an emerging porcine epidemic diarrhea virus (PEDV) variant has gained attention because of serious outbreaks of piglet diarrhea in China and the United States. Coronavirus nonstructural protein 7 (nsp7) has been proposed to act with nsp8 as part of an RNA primase to generate RNA primers for viral RNA synthesis. However, accumulating evidence indicates that coronavirus nsp7 can also antagonize type I IFN production. Our present study extends previous findings and demonstrates that PEDV nsp7 also antagonizes IFN-α-induced IFN signaling by competing with KPNA1 for binding to STAT1, thereby enriching the immune regulation function of coronavirus nsp7.


Subject(s)
Janus Kinase 1 , Porcine epidemic diarrhea virus , STAT1 Transcription Factor , Signal Transduction , Viral Nonstructural Proteins , alpha Karyopherins , Animals , Cell Line , Interferons/metabolism , Janus Kinase 1/metabolism , Porcine epidemic diarrhea virus/genetics , STAT1 Transcription Factor/metabolism , Swine , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism , alpha Karyopherins/metabolism
3.
Int J Mol Sci ; 23(8)2022 Apr 07.
Article in English | MEDLINE | ID: covidwho-1785745

ABSTRACT

The signal transducer and activator of transcription (STAT) 1 protein plays a key role in the immune response against viruses and other pathogens by transducing, in the nucleus, the signal from type I, type II and type III IFNs. STAT1 activates the transcription of hundreds of genes, some of which have been well characterized for their antiviral properties. STAT1 gene deletion in mice and complete STAT1 deficiency in humans both cause rapid death from severe infections. STAT1 plays a key role in the immunoglobulin class-switch recombination through the upregulation of T-bet; it also plays a key role in the production of T-bet+ memory B cells that contribute to tissue-resident humoral memory by mounting an IgG response during re-infection. Considering the key role of STAT1 in the antiviral immune response, many viruses, including dangerous viruses such as Ebola and SARS-CoV-2, have developed different mechanisms to inhibit this transcription factor. The search for drugs capable of targeting the viral proteins implicated in both viral replication and IFN/STAT1 inhibition is important for the treatment of the most dangerous viral infections and for future viral pandemics, as shown by the clinical results obtained with Paxlovid in patients infected with SARS-CoV-2.


Subject(s)
COVID-19 , Virus Diseases , Animals , Antiviral Agents/pharmacology , Humans , Mice , SARS-CoV-2 , STAT1 Transcription Factor/metabolism , Virus Replication
5.
PLoS Pathog ; 17(8): e1009800, 2021 08.
Article in English | MEDLINE | ID: covidwho-1435629

ABSTRACT

Type I Interferons (IFN-Is) are a family of cytokines which play a major role in inhibiting viral infection. Resultantly, many viruses have evolved mechanisms in which to evade the IFN-I response. Here we tested the impact of expression of 27 different SARS-CoV-2 genes in relation to their effect on IFN production and activity using three independent experimental methods. We identified six gene products; NSP6, ORF6, ORF7b, NSP1, NSP5 and NSP15, which strongly (>10-fold) blocked MAVS-induced (but not TRIF-induced) IFNß production. Expression of the first three of these SARS-CoV-2 genes specifically blocked MAVS-induced IFNß-promoter activity, whereas all six genes induced a collapse in IFNß mRNA levels, corresponding with suppressed IFNß protein secretion. Five of these six genes furthermore suppressed MAVS-induced activation of IFNλs, however with no effect on IFNα or IFNγ production. In sharp contrast, SARS-CoV-2 infected cells remained extremely sensitive to anti-viral activity exerted by added IFN-Is. None of the SARS-CoV-2 genes were able to block IFN-I signaling, as demonstrated by robust activation of Interferon Stimulated Genes (ISGs) by added interferon. This, despite the reduced levels of STAT1 and phospho-STAT1, was likely caused by broad translation inhibition mediated by NSP1. Finally, we found that a truncated ORF7b variant that has arisen from a mutant SARS-CoV-2 strain harboring a 382-nucleotide deletion associating with mild disease (Δ382 strain identified in Singapore & Taiwan in 2020) lost its ability to suppress type I and type III IFN production. In summary, our findings support a multi-gene process in which SARS-CoV-2 blocks IFN-production, with ORF7b as a major player, presumably facilitating evasion of host detection during early infection. However, SARS-CoV-2 fails to suppress IFN-I signaling thus providing an opportunity to exploit IFN-Is as potential therapeutic antiviral drugs.


Subject(s)
Interferon-beta/metabolism , SARS-CoV-2/immunology , Viral Proteins/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Vesicular Transport/metabolism , Animals , Chlorocebus aethiops , Eukaryotic Initiation Factor-2/metabolism , HEK293 Cells , Humans , Interferon-beta/genetics , Interferon-beta/pharmacology , SARS-CoV-2/drug effects , STAT1 Transcription Factor/metabolism , Vero Cells , Viral Proteins/genetics
7.
J Virol ; 95(19): e0086221, 2021 09 09.
Article in English | MEDLINE | ID: covidwho-1309804

ABSTRACT

SARS-CoV-2 can infect multiple organs, including lung, intestine, kidney, heart, liver, and brain. The molecular details of how the virus navigates through diverse cellular environments and establishes replication are poorly defined. Here, we generated a panel of phenotypically diverse, SARS-CoV-2-infectible human cell lines representing different body organs and performed longitudinal survey of cellular proteins and pathways broadly affected by the virus. This revealed universal inhibition of interferon signaling across cell types following SARS-CoV-2 infection. We performed systematic analyses of the JAK-STAT pathway in a broad range of cellular systems, including immortalized cells and primary-like cardiomyocytes, and found that SARS-CoV-2 targeted the proximal pathway components, including Janus kinase 1 (JAK1), tyrosine kinase 2 (Tyk2), and the interferon receptor subunit 1 (IFNAR1), resulting in cellular desensitization to type I IFN. Detailed mechanistic investigation of IFNAR1 showed that the protein underwent ubiquitination upon SARS-CoV-2 infection. Furthermore, chemical inhibition of JAK kinases enhanced infection of stem cell-derived cultures, indicating that the virus benefits from inhibiting the JAK-STAT pathway. These findings suggest that the suppression of interferon signaling is a mechanism widely used by the virus to evade antiviral innate immunity, and that targeting the viral mediators of immune evasion may help block virus replication in patients with COVID-19. IMPORTANCE SARS-CoV-2 can infect various organs in the human body, but the molecular interface between the virus and these organs remains unexplored. In this study, we generated a panel of highly infectible human cell lines originating from various body organs and employed these cells to identify cellular processes commonly or distinctly disrupted by SARS-CoV-2 in different cell types. One among the universally impaired processes was interferon signaling. Systematic analysis of this pathway in diverse culture systems showed that SARS-CoV-2 targets the proximal JAK-STAT pathway components, destabilizes the type I interferon receptor though ubiquitination, and consequently renders the infected cells resistant to type I interferon. These findings illuminate how SARS-CoV-2 can continue to propagate in different tissues even in the presence of a disseminated innate immune response.


Subject(s)
COVID-19/metabolism , Host Microbial Interactions/physiology , Janus Kinases/metabolism , SARS-CoV-2/metabolism , Cell Line , Gene Expression Regulation , Humans , Immune Evasion , Immunity, Innate , Interferon Type I/metabolism , Janus Kinase 1/metabolism , Myocytes, Cardiac , Receptor, Interferon alpha-beta/metabolism , STAT1 Transcription Factor/metabolism , Signal Transduction , TYK2 Kinase/metabolism , Virus Replication
8.
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
9.
Eur J Immunol ; 51(9): 2330-2340, 2021 09.
Article in English | MEDLINE | ID: covidwho-1261763

ABSTRACT

The molecular mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike protein was characterized to identify novel therapies. The impact of tofacitinib, IL-6R Ab, or TNFi therapy was determined on Spike protein or LPS/IFN-γ-induced signaling, inflammation, and metabolic reprogramming in MΦs and/or rheumatoid arthritis (RA) fibroblast-like synoviocyte (FLS). ACE2 frequency was markedly expanded in MΦs compared to T cells and RA FLS. Tofacitinib suppresses Spike protein potentiated STAT1 signaling, whereas this function was unchanged by TNFi. Tofacitinib impairs IL-6/IFN/LPS-induced STAT1 and STAT3 phosphorylation in RA MΦs and FLS. Interestingly, tofacitinib had a broader inhibitory effect on the monokines, glycolytic regulators, or oxidative metabolites compared to IL-6R Ab and TNFi in Spike-protein-activated MΦs. In contrast, all three therapies disrupted IFN-α and IFN-ß secretion in response to Spike protein; nonetheless, the IFN-γ was only curtailed by tofacitinib or IL-6R Ab. While tofacitinib counteracted MΦ metabolic rewiring instigated by Spike protein, it was inconsequential on the glycolysis expansion mediated via HK2 and/or LDHA in the activated RA MΦ and FLS. Nevertheless, the potentiated inflammatory response and the diminished oxidative phosphorylation modulated by Spike protein and/or LPS/IFN-γ stimulation in MΦs or RA FLS were reversed by tofacitinib. In conclusion, tofacitinib suppresses MΦ inflammation and immunometabolism triggered by Spike protein and may provide a promising strategy for COVID-19 patients.


Subject(s)
COVID-19/drug therapy , Macrophages/drug effects , Piperidines/pharmacology , Pyrimidines/pharmacology , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/metabolism , Arthritis, Rheumatoid/metabolism , COVID-19/metabolism , Cells, Cultured , Fibroblasts/drug effects , Fibroblasts/metabolism , Humans , Interleukin-6/metabolism , Macrophages/metabolism , Receptors, Interleukin-6/metabolism , STAT1 Transcription Factor/metabolism , STAT3 Transcription Factor/metabolism , Signal Transduction/drug effects , Tumor Necrosis Factor-alpha/metabolism
11.
Cells ; 10(5)2021 05 04.
Article in English | MEDLINE | ID: covidwho-1223956

ABSTRACT

Macrophages comprise a phenotypically and functionally diverse group of hematopoietic cells. Versatile macrophage subsets engage to ensure maintenance of tissue integrity. To perform tissue stress surveillance, macrophages express many different stress-sensing receptors, including purinergic P2X and P2Y receptors that respond to extracellular nucleotides and their sugar derivatives. Activation of G protein-coupled P2Y receptors can be both pro- and anti-inflammatory. Current examples include the observation that P2Y14 receptor promotes STAT1-mediated inflammation in pro-inflammatory M1 macrophages as well as the demonstration that P2Y11 receptor suppresses the secretion of tumor necrosis factor (TNF)-α and concomitantly promotes the release of soluble TNF receptors from anti-inflammatory M2 macrophages. Here, we review macrophage regulation by P2Y purinergic receptors, both in physiological and disease-associated inflammation. Therapeutic targeting of anti-inflammatory P2Y receptor signaling is desirable to attenuate excessive inflammation in infectious diseases such as COVID-19. Conversely, anti-inflammatory P2Y receptor signaling must be suppressed during cancer therapy to preserve its efficacy.


Subject(s)
Inflammation/immunology , Macrophages/immunology , Receptors, Purinergic P2Y/metabolism , Stress, Physiological/immunology , Animals , COVID-19/blood , COVID-19/drug therapy , COVID-19/immunology , Humans , Immunologic Surveillance/drug effects , Immunologic Surveillance/immunology , Inflammation/blood , Inflammation/drug therapy , Macrophages/metabolism , Mice , Neoplasms/blood , Neoplasms/drug therapy , Neoplasms/immunology , Purinergic P2Y Receptor Agonists/pharmacology , Purinergic P2Y Receptor Agonists/therapeutic use , Purinergic P2Y Receptor Antagonists/pharmacology , Purinergic P2Y Receptor Antagonists/therapeutic use , Receptors, Tumor Necrosis Factor/metabolism , STAT1 Transcription Factor/metabolism , Signal Transduction/drug effects , Signal Transduction/immunology , Tumor Necrosis Factor-alpha/metabolism
12.
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
13.
J Virol ; 94(23)2020 11 09.
Article in English | MEDLINE | ID: covidwho-772280

ABSTRACT

SARS-CoV-2, a novel coronavirus (CoV) that causes COVID-19, has recently emerged causing an ongoing outbreak of viral pneumonia around the world. While distinct from SARS-CoV, both group 2B CoVs share similar genome organization, origins to bat CoVs, and an arsenal of immune antagonists. In this report, we evaluate type I interferon (IFN-I) sensitivity of SARS-CoV-2 relative to the original SARS-CoV. Our results indicate that while SARS-CoV-2 maintains similar viral replication to SARS-CoV, the novel CoV is much more sensitive to IFN-I. In Vero E6 and in Calu3 cells, SARS-CoV-2 is substantially attenuated in the context of IFN-I pretreatment, whereas SARS-CoV is not. In line with these findings, SARS-CoV-2 fails to counteract phosphorylation of STAT1 and expression of ISG proteins, while SARS-CoV is able to suppress both. Comparing SARS-CoV-2 and influenza A virus in human airway epithelial cultures, we observe the absence of IFN-I stimulation by SARS-CoV-2 alone but detect the failure to counteract STAT1 phosphorylation upon IFN-I pretreatment, resulting in near ablation of SARS-CoV-2 infection. Next, we evaluated IFN-I treatment postinfection and found that SARS-CoV-2 was sensitive even after establishing infection. Finally, we examined homology between SARS-CoV and SARS-CoV-2 in viral proteins shown to be interferon antagonists. The absence of an equivalent open reading frame 3b (ORF3b) and genetic differences versus ORF6 suggest that the two key IFN-I antagonists may not maintain equivalent function in SARS-CoV-2. Together, the results identify key differences in susceptibility to IFN-I responses between SARS-CoV and SARS-CoV-2 that may help inform disease progression, treatment options, and animal model development.IMPORTANCE With the ongoing outbreak of COVID-19, differences between SARS-CoV-2 and the original SARS-CoV could be leveraged to inform disease progression and eventual treatment options. In addition, these findings could have key implications for animal model development as well as further research into how SARS-CoV-2 modulates the type I IFN response early during infection.


Subject(s)
Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Interferon Type I/pharmacology , Interferon-alpha/pharmacology , SARS Virus/drug effects , Animals , Antiviral Agents/antagonists & inhibitors , Antiviral Agents/metabolism , Betacoronavirus/immunology , Betacoronavirus/physiology , Cell Line , Cell Line, Tumor , Chlorocebus aethiops , Humans , Interferon Type I/antagonists & inhibitors , Interferon Type I/immunology , Interferon Type I/metabolism , Interferon-alpha/antagonists & inhibitors , Interferon-alpha/immunology , Interferon-alpha/metabolism , Phosphorylation , Recombinant Proteins/pharmacology , SARS Virus/immunology , SARS Virus/physiology , SARS-CoV-2 , STAT1 Transcription Factor/metabolism , Signal Transduction , Vero Cells , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Proteins/metabolism , Virus Replication/drug effects
14.
J Infect Dis ; 222(5): 734-745, 2020 08 04.
Article in English | MEDLINE | ID: covidwho-711823

ABSTRACT

Clinical manifestations of coronavirus disease 2019 (COVID-19) vary from asymptomatic virus shedding, nonspecific pharyngitis, to pneumonia with silent hypoxia and respiratory failure. Dendritic cells and macrophages are sentinel cells for innate and adaptive immunity that affect the pathogenesis of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). The interplay between SARS-CoV-2 and these cell types remains unknown. We investigated infection and host responses of monocyte-derived dendritic cells (moDCs) and macrophages (MDMs) infected by SARS-CoV-2. MoDCs and MDMs were permissive to SARS-CoV-2 infection and protein expression but did not support productive virus replication. Importantly, SARS-CoV-2 launched an attenuated interferon response in both cell types and triggered significant proinflammatory cytokine/chemokine expression in MDMs but not moDCs. Investigations suggested that this attenuated immune response to SARS-CoV-2 in moDCs was associated with viral antagonism of STAT1 phosphorylation. These findings may explain the mild and insidious course of COVID-19 until late deterioration.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/immunology , Dendritic Cells/immunology , Interferons/immunology , Monocytes/immunology , Pneumonia, Viral/immunology , STAT1 Transcription Factor/antagonists & inhibitors , Adaptive Immunity , Animals , Betacoronavirus/immunology , Betacoronavirus/isolation & purification , Betacoronavirus/metabolism , COVID-19 , Chemokines/metabolism , Chlorocebus aethiops , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Cytokines/metabolism , Dendritic Cells/metabolism , Dendritic Cells/virology , Humans , Macrophages/immunology , Macrophages/virology , Monocytes/virology , Pandemics , Phosphorylation , Pneumonia, Viral/metabolism , Pneumonia, Viral/virology , SARS-CoV-2 , STAT1 Transcription Factor/immunology , STAT1 Transcription Factor/metabolism , Vero Cells , Virus Replication/physiology , Virus Shedding
15.
Biochem Pharmacol ; 180: 114122, 2020 10.
Article in English | MEDLINE | ID: covidwho-617879

ABSTRACT

An unprecedented biological function of natural cardenolides independent of their membrane target Na+/K+-ATPase is disclosed. Previously, we reported that cardenolides impart anti-transmissible gastroenteritis coronavirus (anti-TGEV) activity through the targeting of Na+/K+-ATPase and its associated PI3K_PDK1_RSK2 signaling. Swine testis cells with Na+/K+-ATPase α1 knocked down exhibited decreased susceptibility to TGEV infectivity and attenuated PI3K_PDK1_RSK2 signaling. Herein, we further explored a Na+/K+-ATPase-independent signaling axis induced by natural cardenolides that also afforded significant anti-coronaviral activity for porcine TGEV and human HCoV-OC43. Using pharmacological inhibition and gene silencing techniques, we found that this anti-TGEV or anti-HCoV-OC43 activity was caused by JAK1 proteolysis and mediated through upstream activation of Ndfip1/2 and its effector NEDD4. This study provides novel insights into the pharmacological effects of natural cardenolides, and is expected to inform their future development as antiviral agents.


Subject(s)
Antiviral Agents/pharmacology , Cardenolides/pharmacology , Coronavirus OC43, Human/drug effects , Janus Kinase 1/metabolism , Sodium-Potassium-Exchanging ATPase/metabolism , Transmissible gastroenteritis virus/drug effects , Virus Replication/drug effects , Animals , Carrier Proteins/metabolism , Cell Line , Down-Regulation/drug effects , Female , Gene Knockdown Techniques , Humans , Leupeptins , Membrane Proteins/metabolism , Mice , Mice, Inbred BALB C , Nedd4 Ubiquitin Protein Ligases/metabolism , Ouabain/pharmacology , Phosphorylation , Protease Inhibitors/pharmacology , Proteolysis , STAT1 Transcription Factor/metabolism , STAT3 Transcription Factor/metabolism , Signal Transduction/drug effects , Swine
16.
Viruses ; 12(6)2020 06 15.
Article in English | MEDLINE | ID: covidwho-598456

ABSTRACT

As more cases of COVID-19 are studied and treated worldwide, it had become apparent that the lethal and most severe cases of pneumonia are due to an out-of-control inflammatory response to the SARS-CoV-2 virus. I explored the putative causes of this specific feature through a detailed genomic comparison with the closest SARS-CoV-2 relatives isolated from bats, as well as previous coronavirus strains responsible for the previous epidemics (SARS-CoV and MERS-CoV). The high variability region of the nsp3 protein was confirmed to exhibit the most variations between closest strains. It was then studied in the context of physiological and molecular data available in the literature. A number of convergent findings suggest de-mono-ADP-ribosylation (de-MARylation) of STAT1 by the SARS-CoV-2 nsp3 as a putative cause of the cytokine storm observed in the most severe cases of COVID-19. This may suggest new therapeutic approaches and help in designing assays to predict the virulence of naturally circulating SARS-like animal coronaviruses.


Subject(s)
ADP-Ribosylation/physiology , Betacoronavirus/genetics , Cytokine Release Syndrome/pathology , STAT1 Transcription Factor/metabolism , Viral Nonstructural Proteins/metabolism , Amino Acid Sequence/genetics , Angiotensin-Converting Enzyme 2 , COVID-19 , Coronavirus Infections/pathology , Coronavirus Papain-Like Proteases , Humans , Inflammation/pathology , Inflammation/virology , Middle East Respiratory Syndrome Coronavirus/genetics , Pandemics , Peptidyl-Dipeptidase A/biosynthesis , Peptidyl-Dipeptidase A/genetics , Pneumonia, Viral/pathology , SARS Virus/genetics , SARS-CoV-2 , Sequence Homology , Viral Nonstructural Proteins/genetics
17.
Cell ; 182(3): 734-743.e5, 2020 08 06.
Article in English | MEDLINE | ID: covidwho-592236

ABSTRACT

COVID-19, caused by SARS-CoV-2, is a virulent pneumonia, with >4,000,000 confirmed cases worldwide and >290,000 deaths as of May 15, 2020. It is critical that vaccines and therapeutics be developed very rapidly. Mice, the ideal animal for assessing such interventions, are resistant to SARS-CoV-2. Here, we overcome this difficulty by exogenous delivery of human ACE2 with a replication-deficient adenovirus (Ad5-hACE2). Ad5-hACE2-sensitized mice developed pneumonia characterized by weight loss, severe pulmonary pathology, and high-titer virus replication in lungs. Type I interferon, T cells, and, most importantly, signal transducer and activator of transcription 1 (STAT1) are critical for virus clearance and disease resolution in these mice. Ad5-hACE2-transduced mice enabled rapid assessments of a vaccine candidate, of human convalescent plasma, and of two antiviral therapies (poly I:C and remdesivir). In summary, we describe a murine model of broad and immediate utility to investigate COVID-19 pathogenesis and to evaluate new therapies and vaccines.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/pathology , Coronavirus Infections/prevention & control , Disease Models, Animal , Pandemics/prevention & control , Pneumonia, Viral/pathology , Pneumonia, Viral/prevention & control , Vaccination , Angiotensin-Converting Enzyme 2 , Animals , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/virology , Drug Evaluation, Preclinical/methods , Female , Humans , Interferon-gamma/genetics , Interferon-gamma/metabolism , Lung/pathology , Lung/virology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Receptor, Interferon alpha-beta/genetics , Receptor, Interferon alpha-beta/metabolism , SARS-CoV-2 , STAT1 Transcription Factor/genetics , STAT1 Transcription Factor/metabolism , Specific Pathogen-Free Organisms , Transduction, Genetic , Vero Cells , Viral Load , Virus Replication
18.
Acta Pharmacol Sin ; 41(9): 1178-1196, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-549299

ABSTRACT

ß-Sitosterol (24-ethyl-5-cholestene-3-ol) is a common phytosterol Chinese medical plants that has been shown to possess antioxidant and anti-inflammatory activity. In this study we investigated the effects of ß-sitosterol on influenza virus-induced inflammation and acute lung injury and the molecular mechanisms. We demonstrate that ß-sitosterol (150-450 µg/mL) dose-dependently suppresses inflammatory response through NF-κB and p38 mitogen-activated protein kinase (MAPK) signaling in influenza A virus (IAV)-infected cells, which was accompanied by decreased induction of interferons (IFNs) (including Type I and III IFN). Furthermore, we revealed that the anti-inflammatory effect of ß-sitosterol resulted from its inhibitory effect on retinoic acid-inducible gene I (RIG-I) signaling, led to decreased STAT1 signaling, thus affecting the transcriptional activity of ISGF3 (interferon-stimulated gene factor 3) complexes and resulting in abrogation of the IAV-induced proinflammatory amplification effect in IFN-sensitized cells. Moreover, ß-sitosterol treatment attenuated RIG-I-mediated apoptotic injury of alveolar epithelial cells (AEC) via downregulation of pro-apoptotic factors. In a mouse model of influenza, pre-administration of ß-sitosterol (50, 200 mg·kg-1·d-1, i.g., for 2 days) dose-dependently ameliorated IAV-mediated recruitment of pathogenic cytotoxic T cells and immune dysregulation. In addition, pre-administration of ß-sitosterol protected mice from lethal IAV infection. Our data suggest that ß-sitosterol blocks the immune response mediated by RIG-I signaling and deleterious IFN production, providing a potential benefit for the treatment of influenza.


Subject(s)
Acute Lung Injury/drug therapy , Antiviral Agents/therapeutic use , DEAD Box Protein 58/metabolism , Inflammation/drug therapy , Signal Transduction/drug effects , Sitosterols/therapeutic use , A549 Cells , Acute Lung Injury/pathology , Acute Lung Injury/virology , Animals , Antiviral Agents/analysis , Apoptosis/drug effects , Dogs , Female , HEK293 Cells , Humans , Inflammation/pathology , Inflammation/virology , Influenza A Virus, H1N1 Subtype/drug effects , Interferon Type I/metabolism , Interferons/metabolism , Lung/pathology , Madin Darby Canine Kidney Cells , Mice, Inbred BALB C , Plants/chemistry , STAT1 Transcription Factor/metabolism , Sitosterols/analysis
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