Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 32
Filter
1.
Emerg Microbes Infect ; 11(1): 964-967, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1740710

ABSTRACT

SARS-CoV-2 has caused the COVID-19 pandemic since early 2020. As of January 2022, the worldwide spreading of SARS-CoV-2 leads to approximately 0.35 billion of human infections and five millions of deaths. Current vaccination is one of the effective ways to control SARS-CoV-2 transmission and reduce the disease severity. However, the antibody level against the immunogen significantly drops several months after the standard two-dose vaccination, and hence a third or fourth dose booster (the same immunogen) has been suggested to boost the antibody response. Here, we described an ultra-effective nasal vaccine booster that potently induced the extraordinary high-level of neutralizing antibody in pre-vaccinated mice. The vaccine booster is composed of a recombinant receptor binding domain of SARS-CoV-2 spike (either wild-type or omicron) fused with a domain of SARS-CoV-2 nucleoprotein. In the absence of adjuvants, a single intranasal administration of the booster in pre-vaccinated mice significantly induced systemic and mucosal antibody responses as evidenced by the elevation of the cross-variant neutralizing antibody and induction of IgA in bronchoalveolar lavage respectively. Most importantly, the single dose nasal vaccine booster (omicron version) potently enhanced the neutralizing activity against authentic SARS-CoV-2 omicron virus infection. Taken together, the induction of respiratory mucosal immunity and the enhancement of cross-variant neutralizing activity by the nasal vaccine booster warrants further clinical trials in humans.


Subject(s)
COVID-19 , Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Mice , Pandemics , SARS-CoV-2
2.
Emerg Microbes Infect ; 11(1): 689-698, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1713523

ABSTRACT

During the investigation of a pet shop outbreak of severe acute respiratory coronavirus 2 (SARS-CoV-2) with probable hamster-to-human transmission, the environmental and hamster samples in epidemiologically linked pet shops were found positive for SARS-CoV-2 Delta variant AY.127 strains which are phylogenetically closely related to patients and reported European strains. This interspecies' spill-over has triggered transmission in 58 patients epidemiologically linked to three pet shops. Incidentally, three dwarf hamsters imported from the Netherlands and centralized in a warehouse distributing animals to pet shops were positive for SARS-CoV-2 spike variant phylogenetically related to European B.1.258 strains from March 2020. This B.1.258 strain almost disappeared in July 2021. While no hamster-to-human transmission of B.1.258-like strain was found in this outbreak, molecular docking showed that its spike receptor-binding domain (RBD) has a similar binding energy to human ACE2 compared to that of Delta variant AY.127. Therefore, the potential of this B.1.258-related spike variant for interspecies jumping cannot be ignored. The co-circulation of B.1.258-related spike variants with Delta AY.127, which originated in Europe and was not previously found in Hong Kong, suggested that hamsters in our wholesale warehouse and retail pet shops more likely have acquired these viruses in the Netherlands or stopovers during delivery by aviation than locally. The risk of human-to-hamster reverse zoonosis by multiple SARS-CoV-2 variants leading to further adaptive spike mutations with subsequent transmission back to humans cannot be underestimated as an outbreak source of COVID-19. Testing imported pet animals susceptible to SARS-CoV-2 is warranted to prevent future outbreaks.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Cricetinae , Hong Kong , Humans , Molecular Docking Simulation , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry
3.
Clin Infect Dis ; 2021 Aug 18.
Article in English | MEDLINE | ID: covidwho-1704370

ABSTRACT

BACKGROUND: Post-vaccination myopericarditis is reported after immunization with COVID-19 mRNA-vaccines. The effect of accidental intravenous injection of this vaccine on the heart is unknown. METHODS: We compared the clinical manifestations, histopathological changes, tissue mRNA expression and serum levels of cytokine/chemokine in Balb/c mice at different time points after intravenous(IV) or intramuscular(IM) vaccine injection with normal saline(NS) control. RESULTS: Though significant weight loss and higher serum cytokine/chemokine levels were found in IM group at 1 to 2 days post-injection(dpi), only IV group developed histopathological changes of myopericarditis as evidenced by cardiomyocyte degeneration, apoptosis and necrosis with adjacent inflammatory cell infiltration and calcific deposits on visceral pericardium, while evidence of coronary artery or other cardiac pathologies was absent. SARS-CoV-2 spike antigen expression by immunostaining was occasionally found in infiltrating immune cells of the heart or injection site, in cardiomyocytes and intracardiac vascular endothelial cells, but not skeletal myocytes. The histological changes of myopericarditis after the first IV-priming dose persisted for 2 weeks and were markedly aggravated by a second IM- or IV-booster dose. Cardiac tissue mRNA expression of IL-1ß, IFN-ß, IL-6 and TNF-α increased significantly from 1dpi to 2dpi in IV but not IM group, compatible with presence of myopericarditis in IV group. Ballooning degeneration of hepatocytes was consistently found in IV group. All other organs appeared normal. CONCLUSIONS: This study provided in-vivo evidence that inadvertent intravenous injection of COVID-19 mRNA-vaccines may induce myopericarditis. Brief withdrawal of syringe plunger to exclude blood aspiration may be one possible way to reduce such risk.

4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-308523

ABSTRACT

SARS-CoV-2 has affected over 9 million patients with more than 460,000 deaths in about 6 months. Understanding the factors that contribute to efficient SARS-CoV-2 infection of human cells, which are not previously reported, may provide insights on SARS-CoV-2 transmissibility and pathogenesis, and reveal targets of intervention. Here, we reported key host and viral determinants that were essential for efficient SARS-CoV-2 infection in the human lung. First, we identified heparan sulfate as an important attachment factor for SARS-CoV-2 infection. Second, we demonstrated that while cell surface sialic acids significantly restricted SARS-CoV infection, SARS-CoV-2 could largely overcome sialic acid-mediated restriction in both human lung epithelial cells and ex vivo human lung tissue explants. Third, we demonstrated that the inserted furin-like cleavage site in SARS-CoV-2 spike was required for efficient virus replication in human lung but not intestine tissues. Overall, these findings contributed to our understanding on efficient SARS-CoV-2 infection of human lungs.

5.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-324830

ABSTRACT

Highly pathogenic coronaviruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 1,2 , Middle East respiratory syndrome coronavirus (MERS-CoV) 3,4 , and SARS-CoV-1 5 vary in their transmissibility and pathogenicity. However, infection by all three viruses result in substantial apoptosis in cell culture 6-8 and in patient samples 9-11 , suggesting a potential link between apoptosis and the pathogenesis of coronaviruses. To date, the underlying mechanism of how apoptosis modulates coronavirus pathogenesis is unknown. Here we show that a cysteine-aspartic protease of the apoptosis cascade, caspase-6, serves as an essential host factor for efficient coronavirus replication. We demonstrate that caspase-6 cleaves coronavirus nucleocapsid (N) proteins, generating N fragments that serve as interferon (IFN) antagonists, thus facilitating virus replication. Inhibition of caspase-6 substantially attenuates the lung pathology and body weight loss of SARS-CoV-2-infected golden Syrian hamsters and improves the survival of mouse-adapted MERS-CoV (MERS-CoV MA )-infected human DPP4 knock-in (hDPP4 KI) mice. Overall, our study reveals how coronaviruses exploit a component of the host apoptosis cascade to facilitate their replication. These results further suggest caspase-6 as a potential target of intervention for the treatment of highly pathogenic coronavirus infections including COVID-19 and MERS.

6.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-324816

ABSTRACT

COVID-19 pandemic is the third zoonotic coronavirus (CoV) outbreak of the century after severe acute respiratory syndrome (SARS) in 2003 and Middle East respiratory syndrome (MERS) since 2012. Treatment options for CoVs are largely lacking. Here, we show that clofazimine, an anti-leprosy drug with a favorable safety and pharmacokinetics profile, possesses pan-coronaviral inhibitory activity, and can antagonize SARS-CoV-2 replication in multiple in vitro systems, including the human embryonic stem cell-derived cardiomyocytes and ex vivo lung cultures. The FDA-approved molecule was found to inhibit multiple steps of viral replication, suggesting multiple underlying antiviral mechanisms. In a hamster model of SARS-CoV-2 pathogenesis, prophylactic or therapeutic administration of clofazimine significantly reduced viral load in the lung and fecal viral shedding, and also prevented cytokine storm associated with viral infection. Additionally, clofazimine exhibited synergy when administered with remdesivir. Since clofazimine is orally bioavailable and has a comparatively low manufacturing cost, it is an attractive clinical candidate for outpatient treatment and remdesivir-based combinatorial therapy for hospitalized COVID-19 patients, particularly in developing countries. Taken together, our data provide evidence that clofazimine may have a role in the control of the current pandemic SARS-CoV-2, endemic MERS-CoV in the Middle East, and, possibly most importantly, emerging CoVs of the future.

9.
Clin Infect Dis ; 73(9): e2946-e2951, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1500988

ABSTRACT

BACKGROUND: Waning immunity occurs in patients who have recovered from Coronavirus Disease 2019 (COVID-19). However, it remains unclear whether true re-infection occurs. METHODS: Whole genome sequencing was performed directly on respiratory specimens collected during 2 episodes of COVID-19 in a patient. Comparative genome analysis was conducted to differentiate re-infection from persistent viral shedding. Laboratory results, including RT-PCR Ct values and serum Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) IgG, were analyzed. RESULTS: The second episode of asymptomatic infection occurred 142 days after the first symptomatic episode in an apparently immunocompetent patient. During the second episode, there was evidence of acute infection including elevated C-reactive protein and SARS-CoV-2 IgG seroconversion. Viral genomes from first and second episodes belong to different clades/lineages. The virus genome from the first episode contained a a stop codon at position 64 of ORF8, leading to a truncation of 58 amino acids. Another 23 nucleotide and 13 amino acid differences located in 9 different proteins, including positions of B and T cell epitopes, were found between viruses from the first and second episodes. Compared to viral genomes in GISAID, the first virus genome was phylogenetically closely related to strains collected in March/April 2020, while the second virus genome was closely related to strains collected in July/August 2020. CONCLUSIONS: Epidemiological, clinical, serological, and genomic analyses confirmed that the patient had re-infection instead of persistent viral shedding from first infection. Our results suggest SARS-CoV-2 may continue to circulate among humans despite herd immunity due to natural infection. Further studies of patients with re-infection will shed light on protective immunological correlates for guiding vaccine design.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Genome, Viral , Humans , Reinfection , Whole Genome Sequencing
10.
Clin Infect Dis ; 2021 Sep 18.
Article in English | MEDLINE | ID: covidwho-1429186

ABSTRACT

BACKGROUND: The effect of low environmental temperature on viral shedding and disease severity of COVID-19 is uncertain. METHODS: We investigated the virological, clinical, pathological, and immunological changes in hamsters housed at room (21 oC), low (12-15 oC), and high (30-33 oC) temperature after challenge by 10 5 plaque-forming units of SARS-CoV-2. RESULTS: The nasal turbinate, trachea, and lung viral load and live virus titre were significantly higher (~0.5-log10 gene copies/ß-actin, p<0.05) in the low temperature group at 7 days post-infection (dpi). The low temperature group also demonstrated significantly higher level of TNF-α, IFN-γ, IL-1ß, and CCL3, and lower level of the antiviral IFN-α in lung tissues at 4dpi than the other two groups. Their lungs were grossly and diffusely haemorrhagic, with more severe and diffuse alveolar and peribronchiolar inflammatory infiltration, bronchial epithelial cell death, and significantly higher mean total lung histology scores. By 7dpi, the low temperature group still showed persistent and severe alveolar inflammation and haemorrhage, and little alveolar cell proliferative changes of recovery. The viral loads in the oral swabs of the low temperature group were significantly higher from 10-17dpi by about 0.5-1.0-log10 gene copies/ß-actin. The mean neutralizing antibody titre of the low temperature group was significantly (p<0.05) lower than that of the room temperature group at 7dpi and 30dpi. CONCLUSIONS: This study provided in-vivo evidence that low environmental temperature exacerbated the degree of virus shedding, disease severity, and tissue proinflammatory cytokines/chemokines expression, and suppressed the neutralizing antibody response of SARS-CoV-2-infected hamsters. Keeping warm in winter may reduce the severity of COVID-19.

11.
Nat Commun ; 12(1): 134, 2021 01 08.
Article in English | MEDLINE | ID: covidwho-1387323

ABSTRACT

Understanding the factors that contribute to efficient SARS-CoV-2 infection of human cells may provide insights on SARS-CoV-2 transmissibility and pathogenesis, and reveal targets of intervention. Here, we analyze host and viral determinants essential for efficient SARS-CoV-2 infection in both human lung epithelial cells and ex vivo human lung tissues. We identify heparan sulfate as an important attachment factor for SARS-CoV-2 infection. Next, we show that sialic acids present on ACE2 prevent efficient spike/ACE2-interaction. While SARS-CoV infection is substantially limited by the sialic acid-mediated restriction in both human lung epithelial cells and ex vivo human lung tissues, infection by SARS-CoV-2 is limited to a lesser extent. We further demonstrate that the furin-like cleavage site in SARS-CoV-2 spike is required for efficient virus replication in human lung but not intestinal tissues. These findings provide insights on the efficient SARS-CoV-2 infection of human lungs.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/pathology , COVID-19/transmission , Sialic Acids/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Virus Attachment , Animals , Caco-2 Cells , Cell Line, Tumor , Chlorocebus aethiops , Cricetinae , Furin/metabolism , HEK293 Cells , Heparitin Sulfate/metabolism , Humans , Intestinal Mucosa/metabolism , Intestines/virology , Lung/pathology , Lung/virology , SARS-CoV-2/physiology , Severe Acute Respiratory Syndrome/pathology , Vero Cells , Virus Internalization , Virus Replication/physiology
12.
Clin Infect Dis ; 2021 Aug 18.
Article in English | MEDLINE | ID: covidwho-1361759

ABSTRACT

BACKGROUND: Post-vaccination myopericarditis is reported after immunization with COVID-19 mRNA-vaccines. The effect of accidental intravenous injection of this vaccine on the heart is unknown. METHODS: We compared the clinical manifestations, histopathological changes, tissue mRNA expression and serum levels of cytokine/chemokine in Balb/c mice at different time points after intravenous(IV) or intramuscular(IM) vaccine injection with normal saline(NS) control. RESULTS: Though significant weight loss and higher serum cytokine/chemokine levels were found in IM group at 1 to 2 days post-injection(dpi), only IV group developed histopathological changes of myopericarditis as evidenced by cardiomyocyte degeneration, apoptosis and necrosis with adjacent inflammatory cell infiltration and calcific deposits on visceral pericardium, while evidence of coronary artery or other cardiac pathologies was absent. SARS-CoV-2 spike antigen expression by immunostaining was occasionally found in infiltrating immune cells of the heart or injection site, in cardiomyocytes and intracardiac vascular endothelial cells, but not skeletal myocytes. The histological changes of myopericarditis after the first IV-priming dose persisted for 2 weeks and were markedly aggravated by a second IM- or IV-booster dose. Cardiac tissue mRNA expression of IL-1ß, IFN-ß, IL-6 and TNF-α increased significantly from 1dpi to 2dpi in IV but not IM group, compatible with presence of myopericarditis in IV group. Ballooning degeneration of hepatocytes was consistently found in IV group. All other organs appeared normal. CONCLUSIONS: This study provided in-vivo evidence that inadvertent intravenous injection of COVID-19 mRNA-vaccines may induce myopericarditis. Brief withdrawal of syringe plunger to exclude blood aspiration may be one possible way to reduce such risk.

13.
Sci Adv ; 7(25)2021 06.
Article in English | MEDLINE | ID: covidwho-1276873

ABSTRACT

Infection by highly pathogenic coronaviruses results in substantial apoptosis. However, the physiological relevance of apoptosis in the pathogenesis of coronavirus infections is unknown. Here, with a combination of in vitro, ex vivo, and in vivo models, we demonstrated that protein kinase R-like endoplasmic reticulum kinase (PERK) signaling mediated the proapoptotic signals in Middle East respiratory syndrome coronavirus (MERS-CoV) infection, which converged in the intrinsic apoptosis pathway. Inhibiting PERK signaling or intrinsic apoptosis both alleviated MERS pathogenesis in vivo. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and SARS-CoV induced apoptosis through distinct mechanisms but inhibition of intrinsic apoptosis similarly limited SARS-CoV-2- and SARS-CoV-induced apoptosis in vitro and markedly ameliorated the lung damage of SARS-CoV-2-inoculated human angiotensin-converting enzyme 2 (hACE2) mice. Collectively, our study provides the first evidence that virus-induced apoptosis is an important disease determinant of highly pathogenic coronaviruses and demonstrates that this process can be targeted to attenuate disease severity.


Subject(s)
Antiviral Agents/pharmacology , Apoptosis/drug effects , COVID-19/drug therapy , Coronavirus Infections/drug therapy , eIF-2 Kinase/metabolism , Adenine/analogs & derivatives , Adenine/pharmacology , Angiotensin-Converting Enzyme 2/genetics , Animals , Apoptosis/physiology , COVID-19/etiology , COVID-19/pathology , Cell Line , Coronavirus Infections/etiology , Coronavirus Infections/pathology , Dipeptidyl Peptidase 4/genetics , Epithelial Cells/virology , Female , Humans , Indoles/pharmacology , Lung/virology , Male , Mice, Transgenic , eIF-2 Kinase/antagonists & inhibitors , eIF-2 Kinase/genetics
14.
Clin Infect Dis ; 72(10): e659-e662, 2021 05 18.
Article in English | MEDLINE | ID: covidwho-1232198

ABSTRACT

We recently reported a patient with coronavirus disease 2019 reinfection. Here, we show that serum neutralizing antibodies could be detected during the first episode but not at the presentation of the second episode. During reinfection, neutralizing antibodies and high avidity immunoglobulin G were found within 8 days after hospitalization, whereas immunoglobulin M response was absent.


Subject(s)
COVID-19 , Antibodies, Neutralizing , Antibodies, Viral , Humans , Immunoglobulin M , Reinfection , SARS-CoV-2
15.
Emerg Microbes Infect ; 10(1): 1016-1023, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1232169

ABSTRACT

Given the on-going SARS-CoV-2 pandemic, identification of immunogenic targets against the viral protein will provide crucial advances towards the development of sensitive diagnostic tools and vaccination strategies. Our previous study has found that ORF8 protein of SARS-CoV-2 is highly immunogenic and shows high sensitivity in identifying COVID-19 disease. In this study, by employing overlapping linear peptides, we characterized the IgG immunodominant regions on SARS-CoV-2 ORF8 protein that are seropositive in the sera from SARS-CoV-2-infected patients. The major immunogenic epitopes are localized at (1) N-termini alpha helix, (2) the resides spanning beta 2 and 3 sheets, and (3) the loop between beta 4 and 5 sheets. Additionally, hamster model infected by SARS-CoV-2 further validates the seropositivity of the linear epitopes in vivo, demonstrating a potential application of the linear peptide-based immunization strategy. Taken together, identification and validation of these B-cell linear epitopes will provide insights into the design of serological diagnostics and peptide-based vaccination approach against this pandemic virus of high priority.


Subject(s)
COVID-19/immunology , Epitopes, B-Lymphocyte , SARS-CoV-2/immunology , Viral Proteins/chemistry , Animals , Antibodies, Viral , Cricetinae , Humans , Immunodominant Epitopes , Mesocricetus , Models, Molecular , Protein Conformation , Viral Proteins/immunology
16.
J Med Virol ; 93(4): 2076-2083, 2021 04.
Article in English | MEDLINE | ID: covidwho-1217369

ABSTRACT

The novel betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged at the end of 2019 and caused the coronavirus disease 19 (COVID-19) pandemic due to its high transmissibility and early immunosuppression. Previous studies on other betacoronaviruses suggested that betacoronavirus infection is associated with the host autophagy pathway. However, it is unclear whether any components of autophagy or virophagy can be therapeutic targets for COVID-19 treatment. In this report, we examined the antiviral effect of four well-characterized small molecule inhibitors that target the key cellular factors involved in key steps of the autophagy pathway. They include small molecules targeting the ULK1/Atg1 complex involved in the induction stage of autophagy (ULK1 inhibitor SBI0206965), the ATG14/Beclin1/VPS34 complex involved in the nucleation step of autophagy (class III PI3-kinase inhibitor VPS34-IN1), and a widely-used autophagy inhibitor that persistently inhibits class I and temporary inhibits class III PI3-kinase (3-MA) and a clinically approved autophagy inhibitor that suppresses autophagy by inhibiting lysosomal acidification and prevents the formation of autophagolysosome (HCQ). Surprisingly, not all the tested autophagy inhibitors suppressed SARS-CoV-2 infection. We showed that inhibition of class III PI3-kinase involved in the initiation step of both canonical and noncanonical autophagy potently suppressed SARS-CoV-2 at a nano-molar level. In addition, this specific kinase inhibitor VPS34-IN1, and its bioavailable analogue VVPS34-IN1, potently inhibited SARS-CoV-2 infection in ex vivo human lung tissues. Taken together, class III PI3-kinase may be a possible target for COVID-19 therapeutic development.


Subject(s)
Antiviral Agents/pharmacology , Autophagy/drug effects , COVID-19/drug therapy , Class III Phosphatidylinositol 3-Kinases/antagonists & inhibitors , Lung , Protein Kinase Inhibitors/pharmacology , Adaptor Proteins, Vesicular Transport/antagonists & inhibitors , Animals , Autophagy-Related Protein-1 Homolog/antagonists & inhibitors , Autophagy-Related Proteins/antagonists & inhibitors , Chlorocebus aethiops , Drug Repositioning , Humans , In Vitro Techniques , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Lung/drug effects , Lung/pathology , Lung/virology , Vero Cells
17.
Emerg Microbes Infect ; 9(1): 221-236, 2020.
Article in English | MEDLINE | ID: covidwho-1169480

ABSTRACT

A mysterious outbreak of atypical pneumonia in late 2019 was traced to a seafood wholesale market in Wuhan of China. Within a few weeks, a novel coronavirus tentatively named as 2019 novel coronavirus (2019-nCoV) was announced by the World Health Organization. We performed bioinformatics analysis on a virus genome from a patient with 2019-nCoV infection and compared it with other related coronavirus genomes. Overall, the genome of 2019-nCoV has 89% nucleotide identity with bat SARS-like-CoVZXC21 and 82% with that of human SARS-CoV. The phylogenetic trees of their orf1a/b, Spike, Envelope, Membrane and Nucleoprotein also clustered closely with those of the bat, civet and human SARS coronaviruses. However, the external subdomain of Spike's receptor binding domain of 2019-nCoV shares only 40% amino acid identity with other SARS-related coronaviruses. Remarkably, its orf3b encodes a completely novel short protein. Furthermore, its new orf8 likely encodes a secreted protein with an alpha-helix, following with a beta-sheet(s) containing six strands. Learning from the roles of civet in SARS and camel in MERS, hunting for the animal source of 2019-nCoV and its more ancestral virus would be important for understanding the origin and evolution of this novel lineage B betacoronavirus. These findings provide the basis for starting further studies on the pathogenesis, and optimizing the design of diagnostic, antiviral and vaccination strategies for this emerging infection.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Genome, Viral , Pneumonia, Viral/virology , Amino Acid Sequence , Betacoronavirus/isolation & purification , COVID-19 , China , Humans , Phylogeny , SARS-CoV-2 , Sequence Analysis, Protein , Travel , Viral Proteins/chemistry , Viral Proteins/genetics
18.
Nature ; 593(7859): 418-423, 2021 05.
Article in English | MEDLINE | ID: covidwho-1137788

ABSTRACT

The COVID-19 pandemic is the third outbreak this century of a zoonotic disease caused by a coronavirus, following the emergence of severe acute respiratory syndrome (SARS) in 20031 and Middle East respiratory syndrome (MERS) in 20122. Treatment options for coronaviruses are limited. Here we show that clofazimine-an anti-leprosy drug with a favourable safety profile3-possesses inhibitory activity against several coronaviruses, and can antagonize the replication of SARS-CoV-2 and MERS-CoV in a range of in vitro systems. We found that this molecule, which has been approved by the US Food and Drug Administration, inhibits cell fusion mediated by the viral spike glycoprotein, as well as activity of the viral helicase. Prophylactic or therapeutic administration of clofazimine in a hamster model of SARS-CoV-2 pathogenesis led to reduced viral loads in the lung and viral shedding in faeces, and also alleviated the inflammation associated with viral infection. Combinations of clofazimine and remdesivir exhibited antiviral synergy in vitro and in vivo, and restricted viral shedding from the upper respiratory tract. Clofazimine, which is orally bioavailable and comparatively cheap to manufacture, is an attractive clinical candidate for the treatment of outpatients and-when combined with remdesivir-in therapy for hospitalized patients with COVID-19, particularly in contexts in which costs are an important factor or specialized medical facilities are limited. Our data provide evidence that clofazimine may have a role in the control of the current pandemic of COVID-19 and-possibly more importantly-in dealing with coronavirus diseases that may emerge in the future.


Subject(s)
Antiviral Agents/pharmacology , Clofazimine/pharmacology , Coronavirus/classification , Coronavirus/drug effects , SARS-CoV-2/drug effects , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Adenosine Monophosphate/therapeutic use , Alanine/analogs & derivatives , Alanine/pharmacology , Alanine/therapeutic use , Animals , Anti-Inflammatory Agents/pharmacokinetics , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Antiviral Agents/pharmacokinetics , Antiviral Agents/therapeutic use , Biological Availability , Cell Fusion , Cell Line , Clofazimine/pharmacokinetics , Clofazimine/therapeutic use , Coronavirus/growth & development , Coronavirus/pathogenicity , Cricetinae , DNA Helicases/antagonists & inhibitors , Drug Synergism , Female , Humans , Life Cycle Stages/drug effects , Male , Mesocricetus , Pre-Exposure Prophylaxis , SARS-CoV-2/growth & development , Species Specificity , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Transcription, Genetic/drug effects , Transcription, Genetic/genetics
19.
Clin Infect Dis ; 73(9): 1696-1699, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1120878

ABSTRACT

Throughout the coronavirus disease 2019 (COVID-19) pandemic, divergent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineages have emerged continuously, mostly through the genomic accumulation of substitutions. We report the discovery of a SARS-CoV-2 variant with a novel genomic architecture characterized by absent ORF7a, ORF7b, and ORF8, and a C-terminally modified ORF6 product resulting from partial 5'-untranslated region (UTR) duplication and transposition.


Subject(s)
COVID-19 , SARS-CoV-2 , Genomics , Hong Kong/epidemiology , Humans
20.
Lancet Microbe ; 1(1): e14-e23, 2020 05.
Article in English | MEDLINE | ID: covidwho-1087358

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported from China in January, 2020. SARS-CoV-2 is efficiently transmitted from person to person and, in 2 months, has caused more than 82 000 laboratory-confirmed cases of coronavirus disease 2019 (COVID-19) and 2800 deaths in 46 countries. The total number of cases and deaths has surpassed that of the 2003 severe acute respiratory syndrome coronavirus (SARS-CoV). Although both COVID-19 and severe acute respiratory syndrome (SARS) manifest as pneumonia, COVID-19 is associated with apparently more efficient transmission, fewer cases of diarrhoea, increased mental confusion, and a lower crude fatality rate. However, the underlying virus-host interactive characteristics conferring these observations on transmissibility and clinical manifestations of COVID-19 remain unknown. METHODS: We systematically investigated the cellular susceptibility, species tropism, replication kinetics, and cell damage of SARS-CoV-2 and compared findings with those for SARS-CoV. We compared SARS-CoV-2 and SARS-CoV replication in different cell lines with one-way ANOVA. For the area under the curve comparison between SARS-CoV-2 and SARS-CoV replication in Calu3 (pulmonary) and Caco2 (intestinal) cells, we used Student's t test. We analysed cell damage induced by SARS-CoV-2 and SARS-CoV with one-way ANOVA. FINDINGS: SARS-CoV-2 infected and replicated to comparable levels in human Caco2 cells and Calu3 cells over a period of 120 h (p=0·52). By contrast, SARS-CoV infected and replicated more efficiently in Caco2 cells than in Calu3 cells under the same multiplicity of infection (p=0·0098). SARS-CoV-2, but not SARS-CoV, replicated modestly in U251 (neuronal) cells (p=0·036). For animal species cell tropism, both SARS-CoV and SARS-CoV-2 replicated in non-human primate, cat, rabbit, and pig cells. SARS-CoV, but not SARS-CoV-2, infected and replicated in Rhinolophus sinicus bat kidney cells. SARS-CoV-2 consistently induced significantly delayed and milder levels of cell damage than did SARS-CoV in non-human primate cells (VeroE6, p=0·016; FRhK4, p=0·0004). INTERPRETATION: As far as we know, our study presents the first quantitative data for tropism, replication kinetics, and cell damage of SARS-CoV-2. These data provide novel insights into the lower incidence of diarrhoea, decreased disease severity, and reduced mortality in patients with COVID-19, with respect to the pathogenesis and high transmissibility of SARS-CoV-2 compared with SARS-CoV. FUNDING: May Tam Mak Mei Yin, The Shaw Foundation Hong Kong, Richard Yu and Carol Yu, Michael Seak-Kan Tong, Respiratory Viral Research Foundation, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund, Chan Yin Chuen Memorial Charitable Foundation, Marina Man-Wai Lee, The Hong Kong Hainan Commercial Association South China Microbiology Research Fund, The Jessie & George Ho Charitable Foundation, Perfect Shape Medical, The Consultancy Service for Enhancing Laboratory Surveillance of Emerging Infectious Diseases and Research Capability on Antimicrobial Resistance for the Department of Health of the Hong Kong Special Administrative Region Government, The Theme-Based Research Scheme of the Research Grants Council, Sanming Project of Medicine in Shenzhen, and The High Level-Hospital Program, Health Commission of Guangdong Province, China.


Subject(s)
COVID-19 , SARS Virus , Animals , Caco-2 Cells , Diarrhea , Humans , Kinetics , Rabbits , SARS-CoV-2 , Swine , Tropism
SELECTION OF CITATIONS
SEARCH DETAIL