Replicative Fitness of a SARS-CoV-2 20I/501Y.V1 Variant from Lineage B.1.1.7 in Human Reconstituted Bronchial Epithelium

Touret, Franck; Luciani, Léa; Baronti, Cécile; Cochin, Maxime; Driouich, Jean-Sélim; Gilles, Magali; Thirion, Laurence; Nougairède, Antoine; Lamballerie, Xavier de

doi:10.1128/mbio.00850-21

Cited by 28 publications

(24 citation statements)

References 18 publications

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“…We found substantial inhibition of SARS-CoV-2 VOC propagation, comparable to the original Munich patient isolate in Calu-3 cells using 100 μg/ml EPs 7630 ( Supplementary Figure S1A ). At low concentrations of 10 μg/ml EPs 7630, we did not detect a significant reduction of viral RNA levels, possibly as a consequence of increased replicative fitness reported for the analyzed VOCs ( Pyke et al, 2021 ; Rosenke et al, 2021 ; Touret et al, 2021 ). To exclude unspecific EPs 7630-induced inhibitory effects in Calu-3 cells, virus growth of other enveloped viruses, specifically mumps virus (MuV) and a Rift Valley fever virus (RVFV) clone 13-based reporter virus ( Kuri et al, 2010 ) was tested in the absence and presence of EPs 7630 ( Supplementary Figure S1B ).…”

Section: Resultscontrasting

confidence: 57%

“…In addition, EPs 7630 treatment efficiently reduced SARS-CoV-2 RNA levels in human lung cells infected with VOCs Alpha and Beta, highlighting its broadly-acting antiviral activity and the potential to inhibit newly emerging SARS-CoV-2 variants in the future. Although we detected reduced inhibition of VOC propagation at low concentrations, possibly due to the reported increase of replicative fitness for SARS-CoV-2 Alpha and Beta ( Pyke et al, 2021 ; Rosenke et al, 2021 ; Touret et al, 2021 ), the broadly acting antiviral effects of EPs 7630 were clearly retained.…”

Section: Discussionmentioning

confidence: 57%

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Antiviral and Immunomodulatory Effects of Pelargonium sidoides DC. Root Extract EPs® 7630 in SARS-CoV-2-Infected Human Lung Cells

Papies¹,

Emanuel²,

Heinemann³

et al. 2021

Front. Pharmacol.

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Treatment options for COVID-19 are currently limited. Drugs reducing both viral loads and SARS-CoV-2-induced inflammatory responses would be ideal candidates for COVID-19 therapeutics. Previous in vitro and clinical studies suggest that the proprietary Pelargonium sidoides DC. root extract EPs 7630 has antiviral and immunomodulatory properties, limiting symptom severity and disease duration of infections with several upper respiratory viruses. Here we assessed if EPs 7630 affects SARS-CoV-2 propagation and the innate immune response in the human lung cell line Calu-3. In direct comparison to other highly pathogenic CoV (SARS-CoV, MERS-CoV), SARS-CoV-2 growth was most efficiently inhibited at a non-toxic concentration with an IC50 of 1.61 μg/ml. Particularly, the cellular entry step of SARS-CoV-2 was significantly reduced by EPs 7630 pretreatment (10–100 μg/ml) as shown by spike protein-carrying pseudovirus particles and infectious SARS-CoV-2. Using sequential ultrafiltration, EPs 7630 was separated into fractions containing either prodelphinidins of different oligomerization degrees or small molecule constituents like benzopyranones and purine derivatives. Prodelphinidins with a low oligomerization degree and small molecule constituents were most efficient in inhibiting SARS-CoV-2 entry already at 10 μg/ml and had comparable effects on immune gene regulation as EPs 7630. Downregulation of multiple pro-inflammatory genes (CCL5, IL6, IL1B) was accompanied by upregulation of anti-inflammatory TNFAIP3 at 48 h post-infection. At high concentrations (100 μg/ml) moderately oligomerized prodelphinidins reduced SARS-CoV-2 propagation most efficiently and exhibited pronounced immune gene modulation. Assessment of cytokine secretion in EPs 7630-treated and SARS-CoV-2-coinfected Calu-3 cells showed that pro-inflammatory cytokines IL-1β and IL-6 were elevated whereas multiple other COVID-19-associated cytokines (IL-8, IL-13, TNF-α), chemokines (CXCL9, CXCL10), and growth factors (PDGF, VEGF-A, CD40L) were significantly reduced by EPs 7630. SARS-CoV-2 entry inhibition and the differential immunomodulatory functions of EPs 7630 against SARS-CoV-2 encourage further in vivo studies.

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Section: Resultscontrasting

confidence: 57%

Section: Discussionmentioning

confidence: 57%

Antiviral and Immunomodulatory Effects of Pelargonium sidoides DC. Root Extract EPs® 7630 in SARS-CoV-2-Infected Human Lung Cells

Papies¹,

Emanuel²,

Heinemann³

et al. 2021

Front. Pharmacol.

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“…Compared with analyzing individual viruses separately, the competition assay has the advantages of (i) a built-in internal control of each viral replication and (ii) elimination of host-to-host variation that reduces experimental power. Due to its precision and reproducibility 14 , the competition assay has been widely used to study microbial fitness, 15–17 including SARS-CoV-2 1,18 . When infecting human lung adenocarcinoma Calu-3 cells, the RNA ratio of Delta versus Alpha increased to 3.0, 7.0, and 4.1 at 24, 36, and 48 h post infection, respectively ( Extended data Fig.…”

Section: Resultsmentioning

confidence: 99%

Delta spike P681R mutation enhances SARS-CoV-2 fitness over Alpha variant

Liu

Johnson

et al. 2021

Preprint

170

137

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SARS-CoV-2 Delta variant has rapidly replaced the Alpha variant around the world. The mechanism that drives this global replacement has not been defined. Here we report that Delta spike mutation P681R plays a key role in the Alpha-to-Delta variant replacement. In a replication competition assay, Delta SARS-CoV-2 efficiently outcompeted the Alpha variant in human lung epithelial cells and primary human airway tissues. Delta SARS-CoV-2 bearing the Alpha-spike glycoprotein replicated less efficiently than the wild-type Delta variant, suggesting the importance of Delta spike in enhancing viral replication. The Delta spike has accumulated mutation P681R located at a furin cleavage site that separates the spike 1 (S1) and S2 subunits. Reverting the P681R mutation to wild-type P681 significantly reduced the replication of Delta variant, to a level lower than the Alpha variant. Mechanistically, the Delta P681R mutation enhanced the cleavage of the full-length spike to S1 and S2, leading to increased infection via cell surface entry. In contrast, the Alpha spike also has a mutation at the same amino acid (P681H), but the spike cleavage from purified Alpha virions was reduced compared to the Delta spike. Collectively, our results indicate P681R as a key mutation in enhancing Delta variant replication via increased S1/S2 cleavage. Spike mutations that potentially affect furin cleavage efficiency must be closely monitored for future variant surveillance.

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“…Caco-2 cells have been particularly useful in SARS-CoV-2 research due to the fact that unlike Vero E6, which also expresses ACE-2, Caco-2 is able to express the TMPRSS2 coreceptor endogenously, unlike Vero E6 in which TMPRSS2 expression must be induced ( Lee et al., 2020 ). Caco-2 cell line has shown to be useful in areas of research investigating the nature of SARS-CoV-2 such as comparing & contrasting the kinetics of variants in vitro ( Touret et al., 2021 ), the role of integrins in SARS-CoV-2 pathogenesis ( Nader et al., 2021 ), and SARS-CoV-2 transcriptional & post-transcriptional processing dynamics in infected cells ( Chang et al., 2021 ). Similar to Vero E6 cell lines, Caco-2 was also used in studies investigating 6 repurposed drugs in the treatment of SARS-CoV-2 infection with activity against SARS-CoV-2 (i.e.…”

Section: In Vitro Models Of Sars-cov-2 Infectionmentioning

confidence: 99%

Experimental Models of COVID-19

Caldera-Crespo

Paidas

Roy

et al. 2022

Front. Cell. Infect. Microbiol.

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COVID-19 is the most consequential pandemic of the 21st century. Since the earliest stage of the 2019-2020 epidemic, animal models have been useful in understanding the etiopathogenesis of SARS-CoV-2 infection and rapid development of vaccines/drugs to prevent, treat or eradicate SARS-CoV-2 infection. Early SARS-CoV-1 research using immortalized in-vitro cell lines have aided in understanding different cells and receptors needed for SARS-CoV-2 infection and, due to their ability to be easily manipulated, continue to broaden our understanding of COVID-19 disease in in-vivo models. The scientific community determined animal models as the most useful models which could demonstrate viral infection, replication, transmission, and spectrum of illness as seen in human populations. Until now, there have not been well-described animal models of SARS-CoV-2 infection although transgenic mouse models (i.e. mice with humanized ACE2 receptors with humanized receptors) have been proposed. Additionally, there are only limited facilities (Biosafety level 3 laboratories) available to contribute research to aid in eventually exterminating SARS-CoV-2 infection around the world. This review summarizes the most successful animal models of SARS-CoV-2 infection including studies in Non-Human Primates (NHPs) which were found to be susceptible to infection and transmitted the virus similarly to humans (e.g., Rhesus macaques, Cynomolgus, and African Green Monkeys), and animal models that do not require Biosafety level 3 laboratories (e.g., Mouse Hepatitis Virus models of COVID-19, Ferret model, Syrian Hamster model). Balancing safety, mimicking human COVID-19 and robustness of the animal model, the Murine Hepatitis Virus-1 Murine model currently represents the most optimal model for SARS-CoV-2/COVID19 research. Exploring future animal models will aid researchers/scientists in discovering the mechanisms of SARS-CoV-2 infection and in identifying therapies to prevent or treat COVID-19.

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Replicative Fitness of a SARS-CoV-2 20I/501Y.V1 Variant from Lineage B.1.1.7 in Human Reconstituted Bronchial Epithelium

Cited by 28 publications

References 18 publications

Antiviral and Immunomodulatory Effects of Pelargonium sidoides DC. Root Extract EPs® 7630 in SARS-CoV-2-Infected Human Lung Cells

Antiviral and Immunomodulatory Effects of Pelargonium sidoides DC. Root Extract EPs® 7630 in SARS-CoV-2-Infected Human Lung Cells

Delta spike P681R mutation enhances SARS-CoV-2 fitness over Alpha variant

Experimental Models of COVID-19

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