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1.
Angewandte Chemie (International ed. in English) ; 2022.
Article in English | EuropePMC | ID: covidwho-1813460

ABSTRACT

Natural products possessing unique scaffolds may have antiviral activity but their complex structures hinder facile synthesis. A pharmacophore-oriented semisynthesis approach was applied to (-)-maoelactone A ( 1 ) and oridonin ( 2 ) for the discovery of anti-SARS-CoV-2 agents. The Wolff rearrangement/lactonization cascade (WRLC) reaction was developed to construct the unprecedented maoelactone-type scaffold during semisynthesis of 1 . Further mechanistic study suggested a concerted mechanism for Wolff rearrangement and a water-assisted stepwise process for lactonization. The WRLC reaction then enabled the creation of a novel family by assembly of the maoelactone-type scaffold and the pharmacophore of 2 , whereby one derivative inhibited SARS-CoV-2 replication in HPA EpiC cells with a low EC50 value (19 ± 1 nM) and a high TI value (>1000), both values better than those of remdesivir.

2.
Clinical Laboratory News ; 47(8):4-5, 2021.
Article in English | CINAHL | ID: covidwho-1481517
3.
Intern Med J ; 2021 Sep 27.
Article in English | MEDLINE | ID: covidwho-1440763

ABSTRACT

BACKGROUND: Conversion from paper-based to electronic medical records (EMR) may affect the quality and timeliness of the completion of Goals-Of-Care (GOC) documents during hospital admissions, and the COVID-19 pandemic may have further impacted this. AIMS: Determine the impact of EMR and COVID-19 on the proper completion of GOC forms, and the factors associated with inpatient changes in GOC. METHODS: We conducted a cross-sectional study of adult general medicine admissions (Aug 2018-Sep 2020) at Dandenong Hospital (Victoria, Australia). We used interrupted time series to model the changes in the rates of proper GOC completion (adequate documented discussion, completed ≤2 days) after the introduction of EMR and arrival of COVID-19. RESULTS: We included a total of 5147 patients. The pre-EMR GOC proper completion rate was 27.7% (overall completion, 86.5%). There was a decrease in the proper completion rate by 2.21% per month (95% CI: -2.83%, -1.58%) after EMR implementation despite an increase in overall completion rates (91.2%). The main reason for the negative trend was a decline in adequate documentation despite improvements in timeliness. COVID-19 arrival saw a reversal of this negative trend, with proper completion rates increasing by 2.25% per month (95% CI: 1.35%, 3.15%) compared to the EMR period, but also resulted in a higher proportion GOC changes within 2 days of admission. CONCLUSION: EMR improved the timeliness and overall completion rates of GOC at the cost of a lower quality of documented discussion. COVID-19 reversed the negative trend in proper GOC completion but increased the number of early revisions. This article is protected by copyright. All rights reserved.

4.
Proc Natl Acad Sci U S A ; 118(23)2021 06 08.
Article in English | MEDLINE | ID: covidwho-1238060

ABSTRACT

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic and has claimed over 2 million lives worldwide. Although the genetic sequences of SARS-CoV and SARS-CoV-2 have high homology, the clinical and pathological characteristics of COVID-19 differ significantly from those of SARS. How and whether SARS-CoV-2 evades (cellular) immune surveillance requires further elucidation. In this study, we show that SARS-CoV-2 infection leads to major histocompability complex class Ι (MHC-Ι) down-regulation both in vitro and in vivo. The viral protein encoded by open reading frame 8 (ORF8) of SARS-CoV-2, which shares the least homology with SARS-CoV among all viral proteins, directly interacts with MHC-Ι molecules and mediates their down-regulation. In ORF8-expressing cells, MHC-Ι molecules are selectively targeted for lysosomal degradation via autophagy. Thus, SARS-CoV-2-infected cells are much less sensitive to lysis by cytotoxic T lymphocytes. Because ORF8 protein impairs the antigen presentation system, inhibition of ORF8 could be a strategy to improve immune surveillance.


Subject(s)
Antigen Presentation , COVID-19/immunology , Down-Regulation/immunology , Histocompatibility Antigens Class I/immunology , Immune Evasion , SARS-CoV-2/immunology , Viral Proteins/immunology , Animals , Autophagy/genetics , Autophagy/immunology , COVID-19/genetics , Chlorocebus aethiops , HEK293 Cells , Histocompatibility Antigens Class I/genetics , Humans , Lysosomes/genetics , Lysosomes/immunology , Lysosomes/virology , Mice , Mice, Transgenic , SARS-CoV-2/genetics , Vero Cells , Viral Proteins/genetics
5.
Signal Transduct Target Ther ; 6(1): 189, 2021 05 12.
Article in English | MEDLINE | ID: covidwho-1226420

ABSTRACT

Since the outbreak of coronavirus disease 2019 (COVID-19), it has become a global pandemic. The spike (S) protein of etiologic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specifically recognizes human angiotensin-converting enzyme 2 (hACE2) as its receptor, which is recently identified as an interferon (IFN)-stimulated gene. Here, we find that hACE2 exists on the surface of exosomes released by different cell types, and the expression of exosomal hACE2 is increased by IFNα/ß treatment. In particular, exosomal hACE2 can specifically block the cell entry of SARS-CoV-2, subsequently inhibit the replication of SARS-CoV-2 in vitro and ex vivo. Our findings have indicated that IFN is able to upregulate a viral receptor on the exosomes which competitively block the virus entry, exhibiting a potential antiviral strategy.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Exosomes/metabolism , Interferon-alpha/pharmacology , Interferon-beta/pharmacology , SARS-CoV-2/physiology , Virus Internalization/drug effects , Virus Replication/drug effects , Angiotensin-Converting Enzyme 2/genetics , Animals , Chlorocebus aethiops , Exosomes/genetics , Exosomes/virology , HEK293 Cells , Humans , Mice , Mice, Transgenic , Vero Cells
6.
Immunity ; 53(6): 1315-1330.e9, 2020 12 15.
Article in English | MEDLINE | ID: covidwho-967948

ABSTRACT

Various vaccine strategies have been proposed in response to the global COVID-19 pandemic, each with unique strategies for eliciting immune responses. Here, we developed nanoparticle vaccines by covalently conjugating the self-assembled 24-mer ferritin to the receptor binding domain (RBD) and/or heptad repeat (HR) subunits of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) spike (S) protein. Compared to monomer vaccines, nanoparticle vaccines elicited more robust neutralizing antibodies and cellular immune responses. RBD and RBD-HR nanoparticle vaccinated hACE2 transgenic mice vaccinated with RBD and/or RBD-HR nanoparticles exhibited reduced viral load in the lungs after SARS-CoV-2 challenge. RBD-HR nanoparticle vaccines also promoted neutralizing antibodies and cellular immune responses against other coronaviruses. The nanoparticle vaccination of rhesus macaques induced neutralizing antibodies, and T and B cell responses prior to boost immunization; these responses persisted for more than three months. RBD- and HR-based nanoparticles thus present a promising vaccination approach against SARS-CoV-2 and other coronaviruses.


Subject(s)
Bacterial Proteins/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Ferritins/immunology , Helicobacter pylori/metabolism , Recombinant Fusion Proteins/immunology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/metabolism , Antibodies, Viral/metabolism , Bacterial Proteins/chemistry , COVID-19 Vaccines/chemistry , Ferritins/chemistry , Humans , Macaca mulatta , Mice , Mice, Inbred BALB C , Nanoparticles/chemistry , Pandemics , Protein Binding , Spike Glycoprotein, Coronavirus/chemistry , Vaccination
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