Journal: iScience
Article Title: High-throughput screening identifies broad-spectrum Coronavirus entry inhibitors
doi: 10.1016/j.isci.2024.110019
Figure Lengend Snippet: Production of high titer VSVΔG pseudoviruses and quantification of single infection events (A) A schematic representation of the VSVΔG pseudoviruses production process. Viral glycoproteins (yellow) are expressed by plasmid transfection on cell surface. Transfected cells are subsequently infected with recombinant VSV in which the endogenous G glycoprotein (VSV-G) was replaced with a fluorescent reporter (VSVΔG) and complemented with VSV-G (VSVΔG-G). 1 h post-infection, the residual VSVΔG-G is thoroughly washed and the culture is replenished with medium. This results in the production of pseudovirus particles capable of a single round of infection, baring the desired glycoproteins on their surface. Nevertheless, all downstream experiments are performed in the presence of a neutralizing anti-VSV-G antibody (α-G). (B) A widefield image of cells infected with VSVΔG pseudoviruses expressing a fluorescent reporter (GFP; green). Infected cells become round after infection due to the virus-induced cytopathic effect (CPE). (C) (Left) A high magnification overlay image showing the infected GFP-positive cells (green) and nuclei (blue). (Right) The respective segmentation showing infected cells (yellow) and nuclei (cyan). (D–F) Pseudoviral titers in infectious units/mL. To remove any residual infections from VSVΔG-G, the neutralizing α-G antibody was added to all pseudoviruses, ensuring accurate titration. The activity of α-G was tested using VSVΔG-G in the presence and absence of α-G. Two-tailed unpaired t tests were used to evaluate the statistical significance of α-G activity ( p ∗∗≤ 0.01, ∗∗∗∗≤ 0.0001. N experiments = 3, n repeats = 9. (D) Titer of VSVΔG-S W in different cell types showing infection improves upon over-expression of the innate receptor ACE2 and host protease TMPRSS2. (E) Titer of VSVΔG-S W in HEK-293T-ACE2-TMPRSS2 cells showing the effect of modifications to the cytosolic tail of S W . (F) Titer of VSVΔG-G, Wuhan (S W ), Alpha (S α ), Delta (S δ ), Omicron (S ο ), and MERS-CoV S (S M ) showing similar infection levels, with and without DPP4. VSVΔG-G pseudoviruses infected all cell lines at similar levels (D and F). (G) Pseudoviral infectious units/mL of VSVΔG RFP -G and VSVΔG GFP -S W separately or simultaneously result in equivalent titer measurements. (Right) A high magnification overlay image of a well showing VSVΔG RFP -G and VSVΔG GFP -S W infected cells (white and green, respectively). Scale bar is 100 μM (B, C, and G). Error bars represent the SEM.
Article Snippet: SARS-CoV-2 Spike S1 RBD: ACE2 Inhibitor Screening Assay Kit , BPS Bioscience , Cat# 79936.
Techniques: Infection, Plasmid Preparation, Transfection, Recombinant, Expressing, Virus, Titration, Activity Assay, Two Tailed Test, Over Expression