Recent advance of ACE2 and microbiota dysfunction in COVID-19 pathogenesis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 2019 (COVID-19) and has become the world's most pressing public health threat. Although not as common as respiratory symptoms, a substantial proportion of patients with COVID-19 presented the gastrointestinal symptoms. ACE2, as the receptor of SARS-CoV and SARS-CoV-2, is highly expressed in the epithelia of the epithelium cells in lung and intestine. In addition, ACE2 is essential for the innate immunity, amino acid transportation and the homeostasis of intestinal microecology. The composition of gut microbiota in COVID-19 patients was altered and concordant with inflammatory, which may explain the gastrointestinal symptoms in patients. Here we reviewed and discussed the evolving role for ACE2 and gut microbiota in SARS-CoV-2 infection which might provide innovative approaches to targeting ACE2 and gut microbiota for the COVID-19 therapy.