The emergence of a novel coronavirus (2019-nCoV) has awakened the echoes of SARS-CoV from nearly two decades ago. Yet, with technological advances and important lessons gained from previous ...outbreaks, perhaps the world is better equipped to deal with the most recent emergent group 2B coronavirus.
The search for a COVID-19 animal model Lakdawala, Seema S; Menachery, Vineet D
Science (American Association for the Advancement of Science),
05/2020, Letnik:
368, Številka:
6494
Journal Article
Recenzirano
A comparison of SARS-CoV-2 replication, transmission, and disease in mice to monkeys
As the pandemic caused by severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) continues to cause ...worldwide upheaval, scientists are racing to find appropriate animal models to study the coronavirus disease 2019 (COVID-19) attributed to the virus. The optimal animal model will depend on the scientific question. On page 1016 of this issue, Shi
et al.
(
1
) describe severe viral burden and airborne transmission of SARS-CoV-2 between cats and ferrets, highlighting an important animal model for SARS-CoV-2 transmission. Additionally, on page 1012 of this issue, Rockx
et al.
(
2
) found that young and aged cynomolgus macaques infected with SARS-CoV-2 shed virus in the upper and lower respiratory tract, but failed to develop severe clinical symptoms. These animal models offer distinct platforms to ask specific questions about SARS-CoV-2 infection, induction of disease, and transmission.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication and host immune response determine coronavirus disease 2019 (COVID-19), but studies evaluating viral evasion of immune ...response are lacking. Here, we use unbiased screening to identify SARS-CoV-2 proteins that antagonize type I interferon (IFN-I) response. We found three proteins that antagonize IFN-I production via distinct mechanisms: nonstructural protein 6 (nsp6) binds TANK binding kinase 1 (TBK1) to suppress interferon regulatory factor 3 (IRF3) phosphorylation, nsp13 binds and blocks TBK1 phosphorylation, and open reading frame 6 (ORF6) binds importin Karyopherin α 2 (KPNA2) to inhibit IRF3 nuclear translocation. We identify two sets of viral proteins that antagonize IFN-I signaling through blocking signal transducer and activator of transcription 1 (STAT1)/STAT2 phosphorylation or nuclear translocation. Remarkably, SARS-CoV-2 nsp1 and nsp6 suppress IFN-I signaling more efficiently than SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV). Thus, when treated with IFN-I, a SARS-CoV-2 replicon replicates to a higher level than chimeric replicons containing nsp1 or nsp6 from SARS-CoV or MERS-CoV. Altogether, the study provides insights on SARS-CoV-2 evasion of IFN-I response and its potential impact on viral transmission and pathogenesis.
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•SARS-CoV-2 proteins antagonize IFN-I production and signaling•Different SARS-CoV-2 proteins inhibit IFN-I response through distinct mechanisms•SARS-CoV, SARS-CoV-2, and MERS-CoV proteins inhibit IFN-I at different efficacies•A reporter replicon of SARS-CoV-2 allows experiments at biosafety level 2
Xia et al. perform an unbiased screening to identify SARS-CoV-2 proteins that antagonize the IFN-I response. The identified viral proteins inhibit IFN-I production and signaling through distinct mechanisms. Compared with SARS-CoV and MERS-CoV, the IFN-I signaling is more efficiently suppressed by the SARS-CoV-2 nsp1 and nsp6 proteins.
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.
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.
Virus neutralization remains the gold standard for determining antibody efficacy. Therefore, a high-throughput assay to measure SARS-CoV-2 neutralizing antibodies is urgently needed for COVID-19 ...serodiagnosis, convalescent plasma therapy, and vaccine development. Here, we report on a fluorescence-based SARS-CoV-2 neutralization assay that detects SARS-CoV-2 neutralizing antibodies in COVID-19 patient specimens and yields comparable results to plaque reduction neutralizing assay, the gold standard of serological testing. The fluorescence-based neutralization assay is specific to measure COVID-19 neutralizing antibodies without cross reacting with patient specimens with other viral, bacterial, or parasitic infections. Collectively, our approach offers a rapid platform that can be scaled to screen people for antibody protection from COVID-19, a key parameter necessary to safely reopen local communities.
We engineered three severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses containing key spike mutations from the newly emerged United Kingdom (UK) and South African (SA) variants: ...N501Y from UK and SA; 69/70-deletion + N501Y + D614G from UK; and E484K + N501Y + D614G from SA. Neutralization geometric mean titers (GMTs) of 20 BTN162b2 vaccine-elicited human sera against the three mutant viruses were 0.81- to 1.46-fold of the GMTs against parental virus, indicating small effects of these mutations on neutralization by sera elicited by two BNT162b2 doses.
The B.1.1.7 variant (also known as Alpha) of SARS-CoV-2, the cause of the COVID-19 pandemic, emerged in the UK in the summer of 2020. The prevalence of this variant increased rapidly owing to an ...increase in infection and/or transmission efficiency
. The Alpha variant contains 19 nonsynonymous mutations across its viral genome, including 8 substitutions or deletions in the spike protein that interacts with cellular receptors to mediate infection and tropism. Here, using a reverse genetics approach, we show that of the 8 individual spike protein substitutions, only N501Y resulted in consistent fitness gains for replication in the upper airway in a hamster model as well as in primary human airway epithelial cells. The N501Y substitution recapitulated the enhanced viral transmission phenotype of the eight mutations in the Alpha spike protein, suggesting that it is a major determinant of the increased transmission of the Alpha variant. Mechanistically, the N501Y substitution increased the affinity of the viral spike protein for cellular receptors. As suggested by its convergent evolution in Brazil, South Africa and elsewhere
, our results indicate that N501Y substitution is an adaptive spike mutation of major concern.
Efforts towards developing a vaccine for Middle East respiratory syndrome coronavirus (MERS-CoV) have yielded promising results. Utilizing a variety of platforms, several vaccine approaches have ...shown efficacy in animal models and begun to enter clinical trials. In this review, we summarize the current progress towards a MERS-CoV vaccine and highlight potential roadblocks identified from previous attempts to generate coronavirus vaccines.
Acute respiratory distress syndrome (ARDS) is immune-driven pathologies that are observed in severe cases of severe acute respiratory syndrome coronavirus (SARS-CoV) infection. SARS-CoV emerged in ...2002 to 2003 and led to a global outbreak of SARS. As with the outcome of human infection, intranasal infection of C57BL/6J mice with mouse-adapted SARS-CoV results in high-titer virus replication within the lung, induction of inflammatory cytokines and chemokines, and immune cell infiltration within the lung. Using this model, we investigated the role of the complement system during SARS-CoV infection. We observed activation of the complement cascade in the lung as early as day 1 following SARS-CoV infection. To test whether this activation contributed to protective or pathologic outcomes, we utilized mice deficient in C3 (C3
), the central component of the complement system. Relative to C57BL/6J control mice, SARS-CoV-infected
mice exhibited significantly less weight loss and less respiratory dysfunction despite equivalent viral loads in the lung. Significantly fewer neutrophils and inflammatory monocytes were present in the lungs of
mice than in C56BL/6J controls, and subsequent studies revealed reduced lung pathology and lower cytokine and chemokine levels in both the lungs and the sera of
mice than in controls. These studies identify the complement system as an important host mediator of SARS-CoV-induced disease and suggest that complement activation regulates a systemic proinflammatory response to SARS-CoV infection. Furthermore, these data suggest that SARS-CoV-mediated disease is largely immune driven and that inhibiting complement signaling after SARS-CoV infection might function as an effective immune therapeutic.
The complement system is a critical part of host defense to many bacterial, viral, and fungal infections. It works alongside pattern recognition receptors to stimulate host defense systems in advance of activation of the adaptive immune response. In this study, we directly test the role of complement in SARS-CoV pathogenesis using a mouse model and show that respiratory disease is significantly reduced in the absence of complement even though viral load is unchanged. Complement-deficient mice have reduced neutrophilia in their lungs and reduced systemic inflammation, consistent with the observation that SARS-CoV pathogenesis is an immune-driven disease. These data suggest that inhibition of complement signaling might be an effective treatment option following coronavirus infection.
Antiviral therapeutics are a front-line defense against virally induced diseases. Because viruses frequently mutate to escape direct inhibition of viral proteins, there is interest in targeting the ...host proteins that the virus must co-opt to complete its replication cycle. However, a detailed understanding of the interactions between the virus and the host cell is necessary in order to facilitate development of host-directed therapeutics. As a first step, we performed a genome-wide loss of function screen using the alphacoronavirus HCoV-229E to better define the interactions between coronaviruses and host factors. We report the identification and validation of an ER-resident host protein, TMEM41B, as an essential host factor for not only HCoV-229E but also genetically distinct coronaviruses including the pandemic betacoronavirus SARS-CoV-2. We show that the protein is required at an early, but post-receptor engagement, stage of the viral lifecycle. Further, mechanistic studies revealed that although the protein was not enriched at replication complexes, it likely contributes to viral replication complex formation via mobilization of cholesterol and other lipids to facilitate host membrane expansion and curvature. Continued study of TMEM41B and the development of approaches to prevent its function may lead to broad spectrum anti-coronavirus therapeutics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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