Fig. 5: NACE2i induces ACE2 methylation in bronchiolar cells from SARS-CoV-2-infected Syrian golden hamsters.

a Representative H&E images of SARS-CoV-2-infected golden Syrian hamster lungs treated with either vehicle control (n = 7 animals) or NACE2i (n = 8 animals). Scale bar, 200 µm. Blue arrows indicate intact ciliated cells. b Representative immunofluorescence images of lung section from hamsters (n = 3 animals) stained with KRT5 (grey), MUC5AC (green), H3K27ac (magenta), and ACE2^me (red) (scale bar 20 µm). Arrows indicate KRT5⁺ cells with ACE2^me expression. c Representative immunofluorescence images of lung sections from SARS-CoV-2-infected hamsters treated ± NACE2i (n = 3 animals/group). Lung tissues were stained for ACE2 (green) and ACE2^me (red). DAPI (blue) was used to stain nuclei. Arrow indicated the cells enriched with nuclear ACE2. Scale bars are indicated in white. d Bar plots of the population dynamics of nuclear ACE2⁺ and ACE2⁺ACE2^me+ cells (n = 10 FOVs from 3 animals, Ctrl; n = 16 FOVs from 3 animals, NACE2i). Data represent mean ± SEM. Two-sided Welch’s t-test. e Violin plots of the fluorescent intensity of SARS-CoV-2 spike protein, ACE2, and ACE2^me in spike⁺ cells and the population dynamics in lung tissues from SARS-CoV-2-infected hamsters treated with either vehicle control (n = 44 FOVs from 7 animals) or NACE2i (n = 50 FOVs from 8 animals). The ratio of nuclear to cytoplasmic intensity (Fn/c) was calculated for ACE2 (Fn/c > 1 indicates nuclear bias). Black line indicates the medians and dashed line indicates the IQR. Two-sided Welch’s t-test. f Scheme of the SARS-CoV-2 infection in hamsters. At day 0 post-infection (dpi), each hamster was intranasally (i.n.) inoculated with SARS-CoV-2 (n = 3 animals/group), all hamsters were sacrificed and lung tissues were collected at 2 dpi and 5 dpi in a single experiment. g Representative immunofluorescence images of lung sections from hamsters infected with SARS-CoV-2 after 5 days (n = 3 hamsters/group). Lung tissue was stained for SARS-CoV-2 spike (green), F4/80 (red), and ACE2^me (magenta) proteins. DAPI (blue) was used to stain nuclei. h Bar plot of the ASI Digital Pathology analysis in (g) (3 FOVs/animal from n = 3 hamsters/group). Data represent means ± SEM and represent expression of SARS-CoV-2 spike or ACE2^me in two groups of F4/80⁺ cells (day 5 SARS-CoV-2 spike positive, day 5 SARS-CoV-2 spike negative). Two-sided Welch’s t-test.