Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 13 de 13
Filter
1.
Signal Transduct Target Ther ; 7(1): 220, 2022 07 07.
Article in English | MEDLINE | ID: covidwho-1921595

ABSTRACT

COVID-19, caused by SARS-CoV-2, is the most consequential pandemic of this century. Since the outbreak in late 2019, animal models have been playing crucial roles in aiding the rapid development of vaccines/drugs for prevention and therapy, as well as understanding the pathogenesis of SARS-CoV-2 infection and immune responses of hosts. However, the current animal models have some deficits and there is an urgent need for novel models to evaluate the virulence of variants of concerns (VOC), antibody-dependent enhancement (ADE), and various comorbidities of COVID-19. This review summarizes the clinical features of COVID-19 in different populations, and the characteristics of the major animal models of SARS-CoV-2, including those naturally susceptible animals, such as non-human primates, Syrian hamster, ferret, minks, poultry, livestock, and mouse models sensitized by genetically modified, AAV/adenoviral transduced, mouse-adapted strain of SARS-CoV-2, and by engraftment of human tissues or cells. Since understanding the host receptors and proteases is essential for designing advanced genetically modified animal models, successful studies on receptors and proteases are also reviewed. Several improved alternatives for future mouse models are proposed, including the reselection of alternative receptor genes or multiple gene combinations, the use of transgenic or knock-in method, and different strains for establishing the next generation of genetically modified mice.


Subject(s)
COVID-19 , Animals , Cricetinae , Disease Models, Animal , Ferrets , Mice , Peptide Hydrolases , SARS-CoV-2
2.
Cell Discov ; 8(1): 53, 2022 Jun 06.
Article in English | MEDLINE | ID: covidwho-1878521

ABSTRACT

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important target for vaccine and drug development. However, the rapid emergence of variant strains with mutated S proteins has rendered many treatments ineffective. Cleavage of the S protein by host proteases is essential for viral infection. Here, we discovered that the S protein contains two previously unidentified Cathepsin L (CTSL) cleavage sites (CS-1 and CS-2). Both sites are highly conserved among all known SARS-CoV-2 variants. Our structural studies revealed that CTSL cleavage promoted S to adopt receptor-binding domain (RBD) "up" activated conformations, facilitating receptor-binding and membrane fusion. We confirmed that CTSL cleavage is essential during infection of all emerged SARS-CoV-2 variants (including the recently emerged Omicron variant) by pseudovirus (PsV) infection experiment. Furthermore, we found CTSL-specific inhibitors not only blocked infection of PsV/live virus in cells but also reduced live virus infection of ex vivo lung tissues of both human donors and human ACE2-transgenic mice. Finally, we showed that two CTSL-specific inhibitors exhibited excellent In vivo effects to prevent live virus infection in human ACE2-transgenic mice. Our work demonstrated that inhibition of CTSL cleavage of SARS-CoV-2 S protein is a promising approach for the development of future mutation-resistant therapy.

3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-324470

ABSTRACT

The spike (S) protein of SARS coronavirus 2 (SARS-CoV-2) is an ideal target for the development of specific vaccines or drugs. However, treatments targeting viruses with mutant S proteins that have recently emerged in many countries are limited. Cleavage of the S protein by host proteases is essential for viral infection. Here, we discovered two novel sites (CS-1 and CS-2) in the S protein for cleavage by the protease Cathepsin L (CTSL). Both sites are highly conserved among all SARS-CoV-2 variants of concern. Cryo-electron microscopy structural studies revealed that CTSL cleavage increases the dynamics of the receptor binding domain of S and induces novel conformations. In our pseudovirus (PsV) infection experiment, alteration of the cleavage site significantly reduced the infection efficiency, and CTSL inhibitors markedly inhibited infection with PsVs of both the wild-type and emerged SARS-CoV-2 variants. Furthermore, six highly efficient CTSL inhibitors were found to effectively inhibit live virus infection in human cells in vitro , and two of these were further confirmed to prevent live virus infection in human ACE2 transgenic mice in vivo . Our work suggested that the CTSL cleavage sites in SARS-CoV-2 S are emerging new but effective targets for the development of mutation-resistant vaccines and drugs.

4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-317971

ABSTRACT

Jianhui Nie, Qianqian Li, and Jiajing Wu contributed equally to this work. Pseudotyped viruses are useful virological tools due to their safety and versatility. Based on a VSV pseudotyped virus production system, we developed a pseudotyped virus-based neutralization assay against SARS-CoV-2 in biosafety level 2 facilities. This protocol includes production, titration of the SARS-CoV-2 S pseudotyped virus and neutralization assay based on it. Various types of samples targeting virus attachment and entry could be evaluated for their potency, including serum samples derived from animals and humans, monoclonal antibodies, fusion inhibitors (peptides or small molecules). If the pseudotyped virus stock has been prepared in advance, it will take 2 days to get the potency data for the candidate samples. Experience of handling cells is needed before implementing this protocol.

5.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-292884

ABSTRACT

Remarkable progress has been made in developing intramuscular vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2);however, they are limited with respect to eliciting local immunity in the respiratory tract, which is the primary infection site for SARS-CoV-2. To overcome the limitations of intramuscular vaccines, we constructed a nasal vaccine candidate based on an influenza vector by inserting a gene encoding the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, named CA4-dNS1-nCoV-RBD (dNS1-RBD). A preclinical study showed that in hamsters challenged 1 day and 7 days after single-dose vaccination or 6 months after booster vaccination, dNS1-RBD largely mitigated lung pathology, with no loss of body weight, caused by either the prototype-like strain or beta variant of SARS-CoV-2. Lasted data showed that the animals could be well protected against beta variant challenge 9 months after vaccination. Notably, the weight loss and lung pathological changes of hamsters could still be significantly reduced when the hamster was vaccinated 24 h after challenge. Moreover, such cellular immunity is relatively unimpaired for the most concerning SARS-CoV-2 variants. The protective immune mechanism of dNS1-RBD could be attributed to the innate immune response in the nasal epithelium, local RBD-specific T cell response in the lung, and RBD-specific IgA and IgG response. Thus, this study demonstrates that the intranasally delivered dNS1-RBD vaccine candidate may offer an important addition to fight against the ongoing COVID-19 pandemic, compensating limitations of current intramuscular vaccines, particularly at the start of an outbreak.

8.
Signal Transduct Target Ther ; 6(1): 134, 2021 03 27.
Article in English | MEDLINE | ID: covidwho-1152831

ABSTRACT

To discover new drugs to combat COVID-19, an understanding of the molecular basis of SARS-CoV-2 infection is urgently needed. Here, for the first time, we report the crucial role of cathepsin L (CTSL) in patients with COVID-19. The circulating level of CTSL was elevated after SARS-CoV-2 infection and was positively correlated with disease course and severity. Correspondingly, SARS-CoV-2 pseudovirus infection increased CTSL expression in human cells in vitro and human ACE2 transgenic mice in vivo, while CTSL overexpression, in turn, enhanced pseudovirus infection in human cells. CTSL functionally cleaved the SARS-CoV-2 spike protein and enhanced virus entry, as evidenced by CTSL overexpression and knockdown in vitro and application of CTSL inhibitor drugs in vivo. Furthermore, amantadine, a licensed anti-influenza drug, significantly inhibited CTSL activity after SARS-CoV-2 pseudovirus infection and prevented infection both in vitro and in vivo. Therefore, CTSL is a promising target for new anti-COVID-19 drug development.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/metabolism , Cathepsin L , Cysteine Proteinase Inhibitors/pharmacology , Drug Development , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Virus Internalization/drug effects , Adolescent , Adult , Aged , Animals , COVID-19/drug therapy , COVID-19/genetics , Cathepsin L/antagonists & inhibitors , Cathepsin L/genetics , Cathepsin L/metabolism , Female , Humans , Male , Mice , Mice, Transgenic , Middle Aged , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
9.
Natl Sci Rev ; 8(3): nwaa297, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-990776

ABSTRACT

Receptor recognition and subsequent membrane fusion are essential for the establishment of successful infection by SARS-CoV-2. Halting these steps can cure COVID-19. Here we have identified and characterized a potent human monoclonal antibody, HB27, that blocks SARS-CoV-2 attachment to its cellular receptor at sub-nM concentrations. Remarkably, HB27 can also prevent SARS-CoV-2 membrane fusion. Consequently, a single dose of HB27 conferred effective protection against SARS-CoV-2 in two established mouse models. Rhesus macaques showed no obvious adverse events when administrated with 10 times the effective dose of HB27. Cryo-EM studies on complex of SARS-CoV-2 trimeric S with HB27 Fab reveal that three Fab fragments work synergistically to occlude SARS-CoV-2 from binding to the ACE2 receptor. Binding of the antibody also restrains any further conformational changes of the receptor binding domain, possibly interfering with progression from the prefusion to the postfusion stage. These results suggest that HB27 is a promising candidate for immuno-therapies against COVID-19.

10.
Nat Protoc ; 15(11): 3699-3715, 2020 11.
Article in English | MEDLINE | ID: covidwho-797534

ABSTRACT

Pseudotyped viruses are useful virological tools because of their safety and versatility. On the basis of a vesicular stomatitis virus (VSV) pseudotyped virus production system, we developed a pseudotyped virus-based neutralization assay against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in biosafety level 2 facilities. Compared with the binding antibody test, the neutralization assay could discriminate the protective agents from the antibody family. This protocol includes production and titration of the SARS-CoV-2 S pseudotyped virus and the neutralization assay based on it. Various types of samples targeting virus attachment and entry could be evaluated for their potency, including serum samples derived from animals and humans, monoclonal antibodies and fusion inhibitors (peptides or small molecules). If the pseudotyped virus stock has been prepared in advance, it will take 2 days to get the potency data for the candidate samples. Experience in handling cells is needed before implementing this protocol.


Subject(s)
Antibodies, Neutralizing/analysis , Betacoronavirus/immunology , Coronavirus Infections/virology , Genetic Techniques , Pneumonia, Viral/virology , Animals , COVID-19 , Female , HEK293 Cells , Humans , Mice , Pandemics , SARS-CoV-2
11.
Cell Host Microbe ; 28(1): 124-133.e4, 2020 07 08.
Article in English | MEDLINE | ID: covidwho-378130

ABSTRACT

Since December 2019, a novel coronavirus SARS-CoV-2 has emerged and rapidly spread throughout the world, resulting in a global public health emergency. The lack of vaccine and antivirals has brought an urgent need for an animal model. Human angiotensin-converting enzyme II (ACE2) has been identified as a functional receptor for SARS-CoV-2. In this study, we generated a mouse model expressing human ACE2 (hACE2) by using CRISPR/Cas9 knockin technology. In comparison with wild-type C57BL/6 mice, both young and aged hACE2 mice sustained high viral loads in lung, trachea, and brain upon intranasal infection. Although fatalities were not observed, interstitial pneumonia and elevated cytokines were seen in SARS-CoV-2 infected-aged hACE2 mice. Interestingly, intragastric inoculation of SARS-CoV-2 was seen to cause productive infection and lead to pulmonary pathological changes in hACE2 mice. Overall, this animal model described here provides a useful tool for studying SARS-CoV-2 transmission and pathogenesis and evaluating COVID-19 vaccines and therapeutics.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections , Disease Models, Animal , Mice, Inbred C57BL , Pandemics , Pneumonia, Viral , Aging , Angiotensin-Converting Enzyme 2 , Animals , Brain/virology , COVID-19 , CRISPR-Cas Systems , Coronavirus Infections/pathology , Coronavirus Infections/virology , Cytokines/blood , Gene Knock-In Techniques , Lung/pathology , Lung/virology , Lung Diseases, Interstitial/pathology , Nose/virology , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , RNA, Viral/analysis , SARS-CoV-2 , Stomach/virology , Trachea/virology , Viral Load , Virus Replication
12.
Science ; 368(6496): 1274-1278, 2020 06 12.
Article in English | MEDLINE | ID: covidwho-260594

ABSTRACT

Neutralizing antibodies could potentially be used as antivirals against the coronavirus disease 2019 (COVID-19) pandemic. Here, we report isolation of four human-origin monoclonal antibodies from a convalescent patient, all of which display neutralization abilities. The antibodies B38 and H4 block binding between the spike glycoprotein receptor binding domain (RBD) of the virus and the cellular receptor angiotensin-converting enzyme 2 (ACE2). A competition assay indicated different epitopes on the RBD for these two antibodies, making them a potentially promising virus-targeting monoclonal antibody pair for avoiding immune escape in future clinical applications. Moreover, a therapeutic study in a mouse model validated that these antibodies can reduce virus titers in infected lungs. The RBD-B38 complex structure revealed that most residues on the epitope overlap with the RBD-ACE2 binding interface, explaining the blocking effect and neutralizing capacity. Our results highlight the promise of antibody-based therapeutics and provide a structural basis for rational vaccine design.


Subject(s)
Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/therapeutic use , Coronavirus Infections/therapy , Peptidyl-Dipeptidase A/immunology , Pneumonia, Viral/therapy , Receptors, Virus/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2 , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/isolation & purification , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/isolation & purification , Antibodies, Viral/immunology , Antibodies, Viral/isolation & purification , COVID-19 , Disease Models, Animal , Humans , Immunodominant Epitopes/chemistry , Immunodominant Epitopes/immunology , Lung/immunology , Lung/virology , Mice , Neutralization Tests , Pandemics , Protein Domains , Viral Load/immunology
13.
Emerg Microbes Infect ; 9(1): 680-686, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-13830

ABSTRACT

Pseudoviruses are useful virological tools because of their safety and versatility, especially for emerging and re-emerging viruses. Due to its high pathogenicity and infectivity and the lack of effective vaccines and therapeutics, live SARS-CoV-2 has to be handled under biosafety level 3 conditions, which has hindered the development of vaccines and therapeutics. Based on a VSV pseudovirus production system, a pseudovirus-based neutralization assay has been developed for evaluating neutralizing antibodies against SARS-CoV-2 in biosafety level 2 facilities. The key parameters for this assay were optimized, including cell types, cell numbers, virus inoculum. When tested against the SARS-CoV-2 pseudovirus, SARS-CoV-2 convalescent patient sera showed high neutralizing potency, which underscore its potential as therapeutics. The limit of detection for this assay was determined as 22.1 and 43.2 for human and mouse serum samples respectively using a panel of 120 negative samples. The cutoff values were set as 30 and 50 for human and mouse serum samples, respectively. This assay showed relatively low coefficient of variations with 15.9% and 16.2% for the intra- and inter-assay analyses respectively. Taken together, we established a robust pseudovirus-based neutralization assay for SARS-CoV-2 and are glad to share pseudoviruses and related protocols with the developers of vaccines or therapeutics to fight against this lethal virus.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Immune Sera/immunology , Neutralization Tests , Pneumonia, Viral/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , COVID-19 , Cell Line , Coronavirus Infections/therapy , Humans , Immunization, Passive , Limit of Detection , Membrane Glycoproteins/immunology , Mice , Plasmids , Reproducibility of Results , SARS-CoV-2 , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus/genetics , Vesicular stomatitis Indiana virus/genetics , Viral Envelope Proteins/immunology , Virus Internalization
SELECTION OF CITATIONS
SEARCH DETAIL