ACE2 and COVID-19: Figure 8A suggests that salmeterol could interact with STAT3 through integrating PPIs, providing the potential anti-SARS-CoV-2 mechanism of salmeterol. Indeed, STAT3 has been reported to affect ACE2 expression, which may be considered as a potential target for treating COVID-19 patients (Matsuyama et al., 2020; Shamir et al., 2020). Thus, it is likely that salmeterol could fight against COVID-19 via acting on STAT3.