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1.
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.

2.
PLoS Pathog ; 18(2): e1010343, 2022 02.
Article in English | MEDLINE | ID: covidwho-1690680

ABSTRACT

The continuous emergence of severe acute respiratory coronavirus 2 (SARS-CoV-2) variants and the increasing number of breakthrough infection cases among vaccinated people support the urgent need for research and development of antiviral drugs. Viral entry is an intriguing target for antiviral drug development. We found that diltiazem, a blocker of the L-type calcium channel Cav1.2 pore-forming subunit (Cav1.2 α1c) and an FDA-approved drug, inhibits the binding and internalization of SARS-CoV-2, and decreases SARS-CoV-2 infection in cells and mouse lung. Cav1.2 α1c interacts with SARS-CoV-2 spike protein and ACE2, and affects the attachment and internalization of SARS-CoV-2. Our finding suggests that diltiazem has potential as a drug against SARS-CoV-2 infection and that Cav1.2 α1c is a promising target for antiviral drug development for COVID-19.


Subject(s)
COVID-19 , Diltiazem/pharmacology , Lung/drug effects , SARS-CoV-2/drug effects , A549 Cells , Animals , COVID-19/drug therapy , COVID-19/pathology , COVID-19/virology , Cells, Cultured , Chlorocebus aethiops , Diltiazem/therapeutic use , Disease Models, Animal , Female , HEK293 Cells , HeLa Cells , Humans , Lung/pathology , Lung/virology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Transgenic , SARS-CoV-2/physiology , Vero Cells , Virus Attachment/drug effects , Virus Internalization/drug effects
3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-307411

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative pathogen of novel coronavirus disease 2019 (COVID-19)1. SARS-CoV-2 uses angiotensin converting enzyme 2 (ACE2) as a cellular receptor and enters cells via clathrin-mediated endocytosis (CME)2-4. However, the key molecules involved in internalizing and facilitating CME for virus entry remain unknown. Here, we found metabotropic glutamate receptor subtype 2 (mGluR2) is a key entry receptor for SARS-CoV-2 infection. mGluR2 directly interacts with the SARS-CoV-2 spike protein. Knockdown of mGluR2 decreases endocytosis of SARS-CoV-2 but not cell binding. mGluR2 cooperates with ACE2 to facilitate SARS-CoV-2 entry through CME. Knockout of the mGluR2 gene in mice abolished SARS-CoV-2 infection in the nasal turbinates and significantly reduced viral infection in the lungs. Importantly, mGluR2 also is important for severe acute respiratory syndrome coronavirus spike protein and Middle East respiratory syndrome coronavirus spike protein mediated endocytosis. Our study provides important insights into SARS-CoV-2 infection and reveals an important target for the development of novel approaches to limit coronavirus infection.

4.
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.

6.
Cell Discov ; 7(1): 119, 2021 Dec 14.
Article in English | MEDLINE | ID: covidwho-1569245

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses angiotensin-converting enzyme 2 (ACE2) as a binding receptor to enter cells via clathrin-mediated endocytosis (CME). However, receptors involved in other steps of SARS-CoV-2 infection remain largely unknown. Here, we found that metabotropic glutamate receptor subtype 2 (mGluR2) is an internalization factor for SARS-CoV-2. Our results show that mGluR2 directly interacts with the SARS-CoV-2 spike protein and that knockdown of mGluR2 decreases internalization of SARS-CoV-2 but not cell binding. Further, mGluR2 is uncovered to cooperate with ACE2 to facilitate SARS-CoV-2 internalization through CME and mGluR2 knockout in mice abolished SARS-CoV-2 infection in the nasal turbinates and significantly reduced viral infection in the lungs. Notably, mGluR2 is also important for SARS-CoV spike protein- and Middle East respiratory syndrome coronavirus spike protein-mediated internalization. Thus, our study identifies a novel internalization factor used by SARS-CoV-2 and opens a new door for antiviral development against coronavirus infection.

7.
Natl Sci Rev ; 8(3): nwaa291, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-977391

ABSTRACT

Minks are raised in many countries and have transmitted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to humans. However, the biologic properties of SARS-CoV-2 in minks are largely unknown. Here, we investigated and found that SARS-CoV-2 replicates efficiently in both the upper and lower respiratory tracts, and transmits efficiently in minks via respiratory droplets; pulmonary lesions caused by SARS-CoV-2 in minks are similar to those seen in humans with COVID-19. We further found that a spike protein-based subunit vaccine largely prevented SARS-CoV-2 replication and lung damage caused by SARS-CoV-2 infection in minks. Our study indicates that minks are a useful animal model for evaluating the efficacy of drugs or vaccines against COVID-19 and that vaccination is a potential strategy to prevent minks from transmitting SARS-CoV-2.

9.
Science ; 368(6494): 1016-1020, 2020 05 29.
Article in English | MEDLINE | ID: covidwho-45712

ABSTRACT

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) causes the infectious disease COVID-19 (coronavirus disease 2019), which was first reported in Wuhan, China, in December 2019. Despite extensive efforts to control the disease, COVID-19 has now spread to more than 100 countries and caused a global pandemic. SARS-CoV-2 is thought to have originated in bats; however, the intermediate animal sources of the virus are unknown. In this study, we investigated the susceptibility of ferrets and animals in close contact with humans to SARS-CoV-2. We found that SARS-CoV-2 replicates poorly in dogs, pigs, chickens, and ducks, but ferrets and cats are permissive to infection. Additionally, cats are susceptible to airborne transmission. Our study provides insights into the animal models for SARS-CoV-2 and animal management for COVID-19 control.


Subject(s)
Animals, Domestic , Betacoronavirus/physiology , Coronavirus Infections , Disease Models, Animal , Disease Susceptibility , Ferrets , Pandemics , Pneumonia, Viral , Animals , Antibodies, Viral/blood , Betacoronavirus/immunology , Betacoronavirus/isolation & purification , COVID-19 , Cats , Chickens , Coronavirus Infections/transmission , Coronavirus Infections/virology , Dogs , Ducks , Feces/virology , Female , Male , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , RNA, Viral/isolation & purification , Respiratory System/virology , SARS-CoV-2 , Species Specificity , Sus scrofa , Virus Attachment , Virus Replication
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