FIG 6.

Autophagy inhibition suppresses SARS-CoV-2 replication and ameliorates pneumonia in xenografted human lung tissues. NCG mice engrafted with human lung tissues were inoculated with 10^5.5 TCID₅₀ of SARS-CoV-2 or a vehicle. PBS or 3-MA (30 mg/kg) was intraperitoneally injected for 6 consecutive days, with the first dose given 2 h before infection. Mice were sacrificed at 12 hpi, 24 hpi, 48 hpi, 72 hpi, and 5 dpi and xenografted human lung tissues were isolated for RT-qPCR, virus titration, immunohistochemistry, and H&E staining. (A) Schematic diagram of the SARS-CoV-2 challenge, drug treatment, and sample collection schedule. (B and C) RT-qPCR analysis of SARS-CoV-2 N (B) and E (C) gene copies in the mock- or SARS-CoV-2-infected human lung tissues, along the indicated timeline. (D) Viral titers of the SARS-CoV-2-infected human lung tissues collected at the indicated times. (E and F) RT-qPCR analysis of SARS-CoV-2 N (E) and E (F) gene copies at 3 and 5 dpi in the mock- or SARS-CoV-2-infected human lungs treated with PBS or 3-MA. (G) Viral titers of SARS-CoV-2-infected human lung tissues from PBS- or 3-MA-treated mice at 3 and 5 dpi. (H) In situ hybridization analysis of SARS-CoV-2 RNA in PBS or 3-MA-treated human lung tissues after SARS-CoV-2 infection at 5 dpi. (I) Immunohistochemistry of LC3 expression in mock- or SARS-CoV-2-infected human lung tissues from PBS or 3-MA-treated mice at 5 dpi. (J) Representative H&E-stained images of mock- or SARS-CoV-2-infected human lung tissues from PBS- or 3-MA-treated mice at 5 dpi. Scale bar = 50 μm. Data were expressed as means ± SEM from three independent experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.001.