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1.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-310439

ABSTRACT

SARS-CoV-2 has caused a global pandemic of Covid-19 since its emergence in December 2019. The infection causes a severe acute respiratory syndrome and may also lead to central nervous system infection and neurological sequelae. We developed and characterized two new organotypic cultures from hamster brainstem and lung tissues that offer the unique opportunity to study the early steps of the pathogenesis and screening of antivirals. Using these models, we validated the early tropism of the virus in the lung and demonstrated that SARS-CoV2 can infect brainstem and cerebellum, mainly by targeting granular neurons. Viral infection induced specific interferon and innate immune responses with patterns specific to each organ along with apoptotic, necroptotic, and pyroptotic cell death. Overall, our data illustrate the potential of rapidly modeling complex tissue level interactions of viral infection in a newly emerged virus.

2.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-308079

ABSTRACT

Patients with COVID-19 may develop abnormal inflammatory response and lymphopenia, followed in some cases by delayed-onset syndromes, often long-lasting after resolution of the initial SARS-CoV-2 infection. As viral infections may activate human endogenous retroviral elements (HERV), we studied the effect of SARS-CoV-2 on HERV-W and HERV-K envelope (ENV) expression, known to be involved in immunological and neurological pathogenesis of human diseases. We demonstrate here that an initial exposure to SARS-CoV-2 virus activates early HERV-W and K transcription in peripheral blood mononuclear cell (PBMC) cultures from healthy donors. Within a week of primary PBMC culture, only HERV-W ENV protein expression was detected in lymphoid cells of some donors, although SARS-CoV-2 infection of PBMC was not observed. HERV activation was reproduced with UV-inactivated virus and with a recombinant spike protein. Interestingly, exposure to SARS-CoV-2 protein induced a significant production of interleukin 6 in PBMC, independently from detectable HERV expression. Altogether, these results show that SARS-CoV-2 viral protein could induce HERV-W ENV expression in lymphocytes from some individuals, underlying the importance to further address the implicated molecular pathways, to understand patients‘ genetic susceptibility associated to the activation of HERV-W and its possible relevance for targeting therapeutic intervention in COVID-19 associated syndromes.

3.
Nat Commun ; 12(1): 5809, 2021 10 04.
Article in English | MEDLINE | ID: covidwho-1450282

ABSTRACT

SARS-CoV-2 has caused a global pandemic of COVID-19 since its emergence in December 2019. The infection causes a severe acute respiratory syndrome and may also spread to central nervous system leading to neurological sequelae. We have developed and characterized two new organotypic cultures from hamster brainstem and lung tissues that offer a unique opportunity to study the early steps of viral infection and screening antivirals. These models are not dedicated to investigate how the virus reaches the brain. However, they allow validating the early tropism of the virus in the lungs and demonstrating that SARS-CoV-2 could infect the brainstem and the cerebellum, mainly by targeting granular neurons. Viral infection induces specific interferon and innate immune responses with patterns specific to each organ, along with cell death by apoptosis, necroptosis, and pyroptosis. Overall, our data illustrate the potential of rapid modeling of complex tissue-level interactions during infection by a newly emerged virus.


Subject(s)
Brain Stem/virology , Lung/virology , Models, Biological , SARS-CoV-2/pathogenicity , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Alanine/analogs & derivatives , Alanine/pharmacology , Alveolar Epithelial Cells/virology , Animals , Antiviral Agents/pharmacology , Brain Stem/cytology , Brain Stem/immunology , Brain Stem/pathology , Cricetinae , Immunity, Innate , Inflammation , Lung/cytology , Lung/immunology , Lung/pathology , Neurons/virology , Organ Culture Techniques , Regulated Cell Death , SARS-CoV-2/drug effects , Viral Tropism
4.
Viruses ; 13(9)2021 09 12.
Article in English | MEDLINE | ID: covidwho-1411086

ABSTRACT

Our therapeutic arsenal against viruses is very limited and the current pandemic of SARS-CoV-2 highlights the critical need for effective antivirals against emerging coronaviruses. Cellular assays allowing a precise quantification of viral replication in high-throughput experimental settings are essential to the screening of chemical libraries and the selection of best antiviral chemical structures. To develop a reporting system for SARS-CoV-2 infection, we generated cell lines expressing a firefly luciferase maintained in an inactive form by a consensus cleavage site for the viral protease 3CLPro of coronaviruses, so that the luminescent biosensor is turned on upon 3CLPro expression or SARS-CoV-2 infection. This cellular assay was used to screen a metabolism-oriented library of 492 compounds to identify metabolic vulnerabilities of coronaviruses for developing innovative therapeutic strategies. In agreement with recent reports, inhibitors of pyrimidine biosynthesis were found to prevent SARS-CoV-2 replication. Among the top hits, we also identified the NADPH oxidase (NOX) inhibitor Setanaxib. The anti-SARS-CoV-2 activity of Setanaxib was further confirmed using ACE2-expressing human pulmonary cells Beas2B as well as human primary nasal epithelial cells. Altogether, these results validate our cell-based functional assay and the interest of screening libraries of different origins to identify inhibitors of SARS-CoV-2 for drug repurposing or development.


Subject(s)
Antiviral Agents/isolation & purification , Biosensing Techniques/methods , Coronavirus 3C Proteases/metabolism , SARS-CoV-2/physiology , Virus Replication , Animals , Antiviral Agents/pharmacology , Cell Line , Chlorocebus aethiops , Drug Discovery , Drug Evaluation, Preclinical , Enzyme Activation , HEK293 Cells , Humans , Luciferases, Firefly/metabolism , Nasal Mucosa/virology , Pyrazolones/pharmacology , Pyridones/pharmacology , SARS-CoV-2/metabolism , Vero Cells , Virus Internalization/drug effects , Virus Replication/drug effects
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