ACE2 and COVID-19: Up to now, a well-known molecular mechanism of COVID-19 is that SARS-CoV-2 can directly or indirectly invade humans by binding to angiotensin converting enzyme 2 [ACE2, an important component of the renin-angiotensin-aldosterone system (RAS)], which can lead to alterations in the ACE2 signaling pathway and subsequently induce lung and myocardial injury (Figure 3) (Liu et al., 2020g; Brojakowska et al., 2020; Sharma, 2020; Wang et al., 2020b; Wang et al., 2020d; Zheng et al., 2020; Zhou et al., 2020).