Fig. 5: CQ enhances SARS-CoV-2 infection by polarizing M0 macrophages to M1 ones.

a AMs pretreated with CQ (10 μM) for 24 h were stained with LysoSensor™ Yellow/Blue DND-160 and the pH value was detected by a microplate reader. b AMs pretreated with CQ (10 μM) for 24 h were stained with pHrodo™ Red dextran and observed by confocal microscopy. Scale bar, 5 μm. c AMs pretreated with CQ (10 μM) for 24 h were infected with SARS-CoV-2 for 30 min, and then cells were cultured with a virus-free medium for another 30 min, 1 h, or 4 h. Cells were fixed for RNAscope with Probe 1 (green color) and 2 (red color). Scale bar, 5 μm. d–f The schematic diagram of experimental design (d). hACE2 transgenic mice were infected with SARS-CoV-2 and then treated with CQ (i.p., 35 mg/kg) once every day for 5 days. The control group (CTRL) received vehicle (water) as a placebo. The lung tissues were fixed to perform the RNAscope analysis with probes 1 (green color) and 2 (red color) (e, n = 4 mice) and H&E staining (f, n = 4 mice). Three lung sections from the left lobe were evaluated for each mouse. The representative image reflected the distributions of damaged lung tissues. Scale bar, 20 μm for e, 50 μm for f. The data represent mean ± SD. In a–c, n = 3 independent experiments. **P < 0.01, ***P < 0.001, by two-tailed Student’s t-test (a–c) or one-way ANOVA (e, f).