scholarly journals The Spike D614G mutation increases SARS-CoV-2 infection of multiple human cell types

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Zharko Daniloski ◽  
Tristan X Jordan ◽  
Juliana K Ilmain ◽  
Xinyi Guo ◽  
Gira Bhabha ◽  
...  
Keyword(s):  
Human Cell ◽  
Human Lung ◽  
Cell Types ◽  
Lung Epithelial Cells ◽  
Site Directed Mutagenesis ◽  
Wild Type ◽  
Protein Variant ◽  
Lung Epithelial ◽  
Minimal Difference ◽  
Novel Variant

A novel variant of the SARS-CoV-2 virus carrying a point mutation in the Spike protein (D614G) has recently emerged and rapidly surpassed others in prevalence. This mutation is in linkage disequilibrium with an ORF1b protein variant (P314L), making it difficult to discern the functional significance of the Spike D614G mutation from population genetics alone. Here, we perform site-directed mutagenesis on wild-type human-codon-optimized Spike to introduce the D614G variant. Using multiple human cell lines, including human lung epithelial cells, we found that the lentiviral particles pseudotyped with Spike D614G are more effective at transducing cells than ones pseudotyped with wild-type Spike. The increased transduction with Spike D614G ranged from 1.3- to 2.4-fold in Caco-2 and Calu-3 cells expressing endogenous ACE2 and from 1.5- to 7.7-fold in A549ACE2 and Huh7.5ACE2 overexpressing ACE2. Furthermore, trans-complementation of SARS-CoV-2 virus with Spike D614G showed an increased infectivity in human cells. Although there is minimal difference in ACE2 receptor binding between the D614 and G614 Spike variants, the G614 variant is more resistant to proteolytic cleavage, suggesting a possible mechanism for the increased transduction.

scholarly journals The Spike D614G mutation increases SARS-CoV-2 infection of multiple human cell types

2020 ◽  
Author(s):  
Zharko Daniloski ◽  
Tristan X. Jordan ◽  
Juliana K. Ilmain ◽  
Xinyi Guo ◽  
Gira Bhabha ◽  
...  
Keyword(s):  
Human Lung ◽  
Cell Types ◽  
Lung Epithelial Cells ◽  
Site Directed Mutagenesis ◽  
Wild Type ◽  
Protein Variant ◽  
Lung Epithelial ◽  
Minimal Difference ◽  
Multiple Cell

AbstractA novel isolate of the SARS-CoV-2 virus carrying a point mutation in the Spike protein (D614G) has recently emerged and rapidly surpassed others in prevalence. This mutation is in linkage disequilibrium with an ORF1b protein variant (P314L), making it difficult to discern the functional significance of the Spike D614G mutation from population genetics alone. Here, we perform site-directed mutagenesis to introduce the D614G variant and show that in multiple cell lines, including human lung epithelial cells, that the D614G mutation is up to 8-fold more effective at transducing cells than wild-type. We demonstrate increased infection using both Spike-pseudotyped lentivirus and intact SARS-CoV-2 virus. Although there is minimal difference in ACE2 receptor binding between the Spike variants, we show that the G614 variant is more resistant to proteolytic cleavage in vitro and in human cells, suggesting a possible mechanism for the increased transduction. This result has important implications for the efficacy of Spike-based vaccines currently under development in protecting against this recent and highly-prevalent SARS-CoV-2 isolate.

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

2021 ◽  
Author(s):  
Yang Liu ◽  
Jianying Liu ◽  
Bryan A. Johnson ◽  
Hongjie Xia ◽  
Zhiqiang Ku ◽  
...  
Keyword(s):  
Human Lung ◽  
Lung Epithelial Cells ◽  
Wild Type ◽  
Competition Assay ◽  
Furin Cleavage ◽  
Cleavage Efficiency ◽  
Furin Cleavage Site ◽  
Lung Epithelial ◽  
The World ◽  
Alpha Variant

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.

Legionella pneumophila induced microRNA expression in human lung epithelial cells

Pneumologie ◽  
2010 ◽  
Vol 64 (S 03) ◽  
Author(s):  
B Schmeck ◽  
B Dolniak ◽  
I Pollock ◽  
C Schulz ◽  
W Bertrams ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Legionella Pneumophila ◽  
Human Lung ◽  
Microrna Expression ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

scholarly journals Effect of Alpha-1 Antitrypsin on CFTR Levels in Primary Human Airway Epithelial Cells Grown at the Air-Liquid-Interface

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2639
Author(s):  
Frauke Stanke ◽  
Sabina Janciauskiene ◽  
Stephanie Tamm ◽  
Sabine Wrenger ◽  
Ellen Luise Raddatz ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Lung ◽  
Liquid Interface ◽  
Lung Epithelial Cells ◽  
Western Blots ◽  
Mesenchymal Transition ◽  
Protein Levels ◽  
Lung Epithelial ◽  
Cftr Protein ◽  
Air Liquid Interface

The cystic fibrosis transmembrane conductance regulator (CFTR) gene is influenced by the fundamental cellular processes like epithelial differentiation/polarization, regeneration and epithelial–mesenchymal transition. Defects in CFTR protein levels and/or function lead to decreased airway surface liquid layer facilitating microbial colonization and inflammation. The SERPINA1 gene, encoding alpha1-antitrypsin (AAT) protein, is one of the genes implicated in CF, however it remains unknown whether AAT has any influence on CFTR levels. In this study we assessed CFTR protein levels in primary human lung epithelial cells grown at the air-liquid-interface (ALI) alone or pre-incubated with AAT by Western blots and immunohistochemistry. Histological analysis of ALI inserts revealed CFTR- and AAT-positive cells but no AAT-CFTR co-localization. When 0.5 mg/mL of AAT was added to apical or basolateral compartments of pro-inflammatory activated ALI cultures, CFTR levels increased relative to activated ALIs. This finding suggests that AAT is CFTR-modulating protein, albeit its effects may depend on the concentration and the route of administration. Human lung epithelial ALI cultures provide a useful tool for studies in detail how AAT or other pharmaceuticals affect the levels and activity of CFTR.

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