Extended Data Fig. 7: Bruceine A and gamabufotalin exhibit mild activity in inhibiting infection of SARS-CoV-2 B.1.1.7 strain in the C57BL6/J mice.
From: Fluorogenic reporter enables identification of compounds that inhibit SARS-CoV-2
(a) Schematic of the experimental design. C57BL6/J mice were infected by the intranasal route with 105 pfu of SARS-CoV-2 (B.1.1.7). Bruceine A and gamabufotalin were used at 3.25 mg/kg by intranasal inoculation at both 24- and 48-h post-infection. (b) Virus loads in the lungs. Lung tissues were collected at 3 days post-infection, homogenized, and supernatants were tittered by plaque assay in Vero-TMPRSS2 cells. Data are shown as mean ± s.d. N = 4 independent animals for compound group, and N = 5 independent animals for vehicle group. 2 plaque assays per animal were conducted. Two-tailed Mann-Whitney test was used for statistical analysis. Significance is noted with asterisks as follow: * p < 0.05. Exact P values: bruceine A 0.0412, gamabufotalin 0.0412. (c) Immunofluorescence images of the C57BL6/J mice lung tissues. The lung slides were stained with antibodies against nucleocapsid protein (N), spike (S) and DAPI. Immunofluorescence of N, S and DAPI are shown with pseudo-colors green, red and blue, respectively. Lower panels correspond to the boxed areas of the upper panels. Scale bar, 100 μm (upper panels); 50 μm (lower panels). (d) Quantification of the immunofluorescence. Data are shown as mean ± s.d. N = 2 independent animals for each treatment group. Three slides per animal were examined. P value, two-sided non-paired t-test between compound- and DMSO-treated groups. ****P < 0.0001. Exact P values: anti-N: bruceine A 1.1E-07, gamabufotalin 1.0E-07; anti-S: bruceine A 1.1E-07, gamabufotalin 5.8E-08.
