Angiotensin-converting enzyme 2: virus accomplice or host defender?

Objective: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to social disruptions, mainly because we know too little about SARS-CoV-2.Methods and Results: In this study, we integrated RNA sequencing results and found that SARS-CoV-2 infection alters aerobic glycolysis, the oxidative pentose phosphate pathway (oxiPPP), and DNA replication in lung tissues and cells. However, the direction of metabolic flux and DNA replication are dominated by angiotensin-converting enzyme 2 (ACE2), a host cell-expressed viral receptor protein. More interestingly, although hosts with a high expression of ACE2 are more likely to be infected with SARS-CoV-2, the invading virus cannot perform nucleic acid replication well due to the restriction of glucose metabolism, eventually resulting in a prolonged infection cycle or infection failure.Conclusion: Our findings preliminarily explain the reasons for the emergence of asymptomatic infections at an early stage, which will provide assistance for the development of detection methods for diagnosing COVID-19.