Fig. 4 

Pre- and post-treatment effects of TAT-ACE2-2 peptide on lung and olfactory bulb tissue in hACE2 transgenic mice infected with VSV-ΔG-GFP-SARS-CoV-2 pseudovirus. A Schematic diagram of peptide injection and viral exposure in hACE2 mice. B Representative fluorescent microscopic images of lung tissue and olfactory bulb treated with TAT-ACE2-2 peptide, vehicle and TAT alone peptide intranasally 15 min before viral exposure. The white arrow indicates the GFP⁺ cells (pseudovirus-infected cells). Scale bar: 150 µm. C Bar graph showing significantly less fluorescence in the lung tissue treated with TAT-ACE2-2 peptide 15 min before viral exposure as compared to vehicle and TAT alone groups. Data are shown as mean ± SEM, and presented as the percentage of the vehicle group. n = 34 – 48 images from 4–5 mice for each group, one-way ANOVA test followed by Tukey’s post hoc test. ****p < 0.0001 as compared to vehicle group, ####p < 0.0001 as compared to TAT-ACE2-2 group. D Bar graph showing significantly lower total counts of GFP⁺ cells in the OB in the TAT-ACE2-2 peptide-treated group compared to vehicle and TAT alone groups when treated 15 min before viral exposure. Data are shown as mean ± SEM. n = 23 – 49 images from 4–5 mice for each group, one-way ANOVA test followed by Tukey’s post hoc test. ****p < 0.0001 as compared to vehicle group, ####p < 0.0001 as compared to TAT-ACE2-2 group. E Representative fluorescent microscopic images of lung tissue and olfactory bulb treated with TAT-ACE2-2 peptide, vehicle and TAT alone peptide intranasally 1 h after viral exposure. Scale bar: 150 µm. F Bar graph showing that TAT-ACE2-2 treatment 1 h after viral exposure significantly decreases fluorescence in lung tissue as compared to vehicle or TAT alone groups. Data are shown as mean ± SEM, and presented as the percentage of the vehicle group. n = 52 – 65 images from 4–5 mice for each group, one-way ANOVA test followed by Tukey’s post hoc test. ****p < 0.0001 as compared to vehicle group, ####p < 0.0001 as compared to TAT-ACE2-2 group. G Bar graph showing that treatment with TAT-ACE2-2 1 h after viral exposure significantly decreases the number of GFP⁺ cells in the OB tissue as compared to vehicle or TAT alone groups. Data are shown as mean ± SEM. n = 20—26 images from 4–5 mice for each group, one-way ANOVA test followed by Tukey’s post hoc test. ****p < 0.0001 as compared to vehicle group, ####p < 0.0001 as compared to TAT-ACE2-2 group