Figure 4.
The effect of NAC on CSE-induced ACE2 expression, ROS production, and susceptibility to CoV-2 PsV in AMs. (A) The comparison of ACE2 expression and percentage of ACE2-expressing cells between AM and non-AM immune cells before and after treatment with CSE. BAL-derived cells of non-smokers were treated with 1% CSE for 24 h. The ACE2 expression were measured by flow cytometry. (B) The comparison of CoV-2 PsV infection between CSE-treated AMs and the control group. BAL-derived AMs were treated with CSE for 24 h and then incubated with CoV-2 PsV for 72 h. (C,D) Comparison of ACE2 expression and percentage of ACE2-expressing AM (C) and ROS production (D) between AMs treated with 1% CSE alone, 1% CSE and 10 mM NAC, or the control group. The BAL-derived AMs were treated with NAC and/or CSE for 24 h before measuring ACE2 expression, and 30 min before measuring ROS production. (E) The comparison of susceptibility to CoV-2 PsV between AMs treated with CSE alone, CSE and NAC, or the control group. After 24 h of 10 mM NAC and/or 1% CSE treatment, the AMs were incubated with CoV-2 PsV for 72 h, and CoV-2 PsV was measured using flow cytometry. (F,G) The comparison of cytokine production between AMs treated with 1% CSE alone and 1% CSE and 10 mM NAC after CoV-2 PsV inoculation for 72 h (F) or CoV-2 Sp for 24 h (G). Intracellular cytokines were measured using flow cytometry. The columns and error bars represent the means and SEMs of experiments. The statistically significant differences between groups are indicated with * and ** (*P < 0.05, **P < 0.01, paired t test).