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1.
Advanced Therapeutics ; 4(7):2170016, 2021.
Article in English | Wiley | ID: covidwho-1323847

ABSTRACT

SARS-CoV-2 infects human cells by binding its spike protein to the human ACE2 receptor. Using a peptide biopanning strategy, the authors have discovered small anti-ACE2 peptides that can effectively block the SARS-CoV-2/ACE2 interaction. The anti-ACE2 peptides can be potentially used as prophylactic or therapeutic agents for SARS-CoV-2 and other ACE2-mediated viruses. This is reported by Kun Cheng and co-workers in article number 2100087.

2.
mBio ; 12(3)2021 05 11.
Article in English | MEDLINE | ID: covidwho-1225698

ABSTRACT

The spike (S) polypeptide of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) consists of the S1 and S2 subunits and is processed by cellular proteases at the S1/S2 boundary that contains a furin cleavage site (FCS), 682RRAR↓S686 Various deletions surrounding the FCS have been identified in patients. When SARS-CoV-2 propagated in Vero cells, it acquired deletions surrounding the FCS. We studied the viral transcriptome in Vero cell-derived SARS-CoV-2-infected primary human airway epithelia (HAE) cultured at an air-liquid interface (ALI) with an emphasis on the viral genome stability of the FCS. While we found overall the viral transcriptome is similar to that generated from infected Vero cells, we identified a high percentage of mutated viral genome and transcripts in HAE-ALI. Two highly frequent deletions were found at the FCS region: a 12 amino acid deletion (678TNSPRRAR↓SVAS689) that contains the underlined FCS and a 5 amino acid deletion (675QTQTN679) that is two amino acids upstream of the FCS. Further studies on the dynamics of the FCS deletions in apically released virions from 11 infected HAE-ALI cultures of both healthy and lung disease donors revealed that the selective pressure for the FCS maintains the FCS stably in 9 HAE-ALI cultures but with 2 exceptions, in which the FCS deletions are retained at a high rate of >40% after infection of ≥13 days. Our study presents evidence for the role of unique properties of human airway epithelia in the dynamics of the FCS region during infection of human airways, which is likely donor dependent.IMPORTANCE Polarized human airway epithelia at an air-liquid interface (HAE-ALI) are an in vitro model that supports efficient infection of SARS-CoV-2. The spike (S) protein of SARS-CoV-2 contains a furin cleavage site (FCS) at the boundary of the S1 and S2 domains which distinguishes it from SARS-CoV. However, FCS deletion mutants have been identified in patients and in vitro cell cultures, and how the airway epithelial cells maintain the unique FCS remains unknown. We found that HAE-ALI cultures were capable of suppressing two prevalent FCS deletion mutants (Δ678TNSPRRAR↓SVAS689 and Δ675QTQTN679) that were selected during propagation in Vero cells. While such suppression was observed in 9 out of 11 of the tested HAE-ALI cultures derived from independent donors, 2 exceptions that retained a high rate of FCS deletions were also found. Our results present evidence of the donor-dependent properties of human airway epithelia in the evolution of the FCS during infection.


Subject(s)
Bronchi/virology , Furin/metabolism , Respiratory Mucosa/virology , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Transcriptome , Animals , Bronchi/cytology , Cells, Cultured , Chlorocebus aethiops , Epithelial Cells/virology , Humans , RNA-Seq , Respiratory Mucosa/cytology , Sequence Deletion , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells
3.
Adv Ther (Weinh) ; : 2100087, 2021 Apr 26.
Article in English | MEDLINE | ID: covidwho-1201415

ABSTRACT

COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which infects host cells by binding its viral spike protein receptor-binding domain (RBD) to the angiotensin converting enzyme 2 (ACE2) on host cells. Blocking the SARS-CoV-2-RBD/ACE2 interaction is, therefore, a potential strategy to inhibit viral infections. Using a novel biopanning strategy, a small anti-ACE2 peptide is discovered, which shows high affinity and specificity to human ACE2. It blocks not only the SARS-CoV-2-RBD/ACE2 interaction but also the SARS-CoV-1-RBD/ACE2 interaction. Moreover, it inhibits SARS-CoV-2 infection in Vero-E6 cells. The peptide shows negligible cytotoxicity in Vero-E6 cells and Huh7 cells. In vivo short-term lung toxicity study also demonstrates a good safety of the peptide after intratracheal administration. The anti-ACE2 peptide can be potentially used as a prophylactic or therapeutic agent for SARS-CoV-2 or other ACE2-mediated viruses. The strategy used in this study also provides a fast-track platform to discover other antiviral peptides, which will prepare the world for future pandemics.

4.
mBio ; 11(6)2020 11 06.
Article in English | MEDLINE | ID: covidwho-930294

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicates throughout human airways. The polarized human airway epithelium (HAE) cultured at an airway-liquid interface (HAE-ALI) is an in vitro model mimicking the in vivo human mucociliary airway epithelium and supports the replication of SARS-CoV-2. Prior studies characterized only short-period SARS-CoV-2 infection in HAE. In this study, continuously monitoring the SARS-CoV-2 infection in HAE-ALI cultures for a long period of up to 51 days revealed that SARS-CoV-2 infection was long lasting with recurrent replication peaks appearing between an interval of approximately 7 to 10 days, which was consistent in all the tested HAE-ALI cultures derived from 4 lung bronchi of independent donors. We also identified that SARS-CoV-2 does not infect HAE from the basolateral side, and the dominant SARS-CoV-2 permissive epithelial cells are ciliated cells and goblet cells, whereas virus replication in basal cells and club cells was not detected. Notably, virus infection immediately damaged the HAE, which is demonstrated by dispersed zonula occludens-1 (ZO-1) expression without clear tight junctions and partial loss of cilia. Importantly, we identified that SARS-CoV-2 productive infection of HAE requires a high viral load of >2.5 × 105 virions per cm2 of epithelium. Thus, our studies highlight the importance of a high viral load and that epithelial renewal initiates and maintains a recurrent infection of HAE with SARS-CoV-2.IMPORTANCE The pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to >35 million confirmed cases and >1 million fatalities worldwide. SARS-CoV-2 mainly replicates in human airway epithelia in COVID-19 patients. In this study, we used in vitro cultures of polarized human bronchial airway epithelium to model SARS-CoV-2 replication for a period of 21 to 51 days. We discovered that in vitro airway epithelial cultures endure a long-lasting SARS-CoV-2 propagation with recurrent peaks of progeny virus release at an interval of approximately 7 to 10 days. Our study also revealed that SARS-CoV-2 infection causes airway epithelia damage with disruption of tight junction function and loss of cilia. Importantly, SARS-CoV-2 exhibits a polarity of infection in airway epithelium only from the apical membrane; it infects ciliated and goblet cells but not basal and club cells. Furthermore, the productive infection of SARS-CoV-2 requires a high viral load of over 2.5 × 105 virions per cm2 of epithelium. Our study highlights that the proliferation of airway basal cells and regeneration of airway epithelium may contribute to the recurrent infections.


Subject(s)
Betacoronavirus/physiology , Models, Biological , Respiratory Mucosa/virology , Bronchi/cytology , Cells, Cultured , Epithelial Cells/pathology , Epithelial Cells/virology , Humans , Kinetics , Respiratory Mucosa/cytology , Respiratory Mucosa/pathology , SARS-CoV-2 , Viral Load , Viral Tropism , Virus Release , Virus Replication
5.
bioRxiv ; 2020 Aug 28.
Article in English | MEDLINE | ID: covidwho-900750

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicates throughout human airways. The polarized human airway epithelium (HAE) cultured at an airway-liquid interface (HAE-ALI) is an in vitro model mimicking the in vivo human mucociliary airway epithelium and supports the replication of SARS-CoV-2. However, previous studies only characterized short-period SARS-CoV-2 infection in HAE. In this study, continuously monitoring the SARS-CoV-2 infection in HAE-ALI cultures for a long period of up to 51 days revealed that SARS-CoV-2 infection was long lasting with recurrent replication peaks appearing between an interval of approximately 7-10 days, which was consistent in all the tested HAE-ALI cultures derived from 4 lung bronchi of independent donors. We also identified that SARS-CoV-2 does not infect HAE from the basolateral side, and the dominant SARS-CoV-2 permissive epithelial cells are ciliated cells and goblet cells, whereas virus replication in basal cells and club cells was not detectable. Notably, virus infection immediately damaged the HAE, which is demonstrated by dispersed Zonula occludens-1 (ZO-1) expression without clear tight junctions and partial loss of cilia. Importantly, we identified that SARS-CoV-2 productive infection of HAE requires a high viral load of 2.5 × 10 5 virions per cm 2 of epithelium. Thus, our studies highlight the importance of a high viral load and that epithelial renewal initiates and maintains a recurrent infection of HAE with SARS-CoV-2.

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