ACE2 in the Gut: The Center of the 2019-nCoV Infected Pathology

Abstract

The 2019-nCoV is a rapidly contagious pneumonia caused by the recently discovered coronavirus. Although generally the most noticeable symptoms are concentrated in the lungs, the disorders in the gastrointestinal tract are of great importance in the diagnosis of 2019-nCoV. The angiotensin-converting enzyme 2 (ACE2), an important regulator of many physiological functions, including blood pressure and nutrients absorption, is recently identified as a vital entry for 2019-nCoV to enter host cells. In this review, we summarize its functions both physiologically and pathologically. We also elaborate its conflicting roles from the clews of contemporary researches, which may provide significant indications for pharmacological investigations and clinical uses.

Keywords: 2019-nCoV; ACE2; biological actions; function; gut.

FIGURE 1

The roles of ACE2 within the gut. In the meantime, it promotes the SARS-CoV-2 entry into the epithelial cells with the association of TMPRSS2 [shown in (A)]. Besides, as an important regulator of RAS, it cleaves Ang I to Ang-(1–9) and Ang II to Ang-(1–7) and helps with the maintenance of blood pressure [shown in (B)]. ACE2 is widely expressed on the membrane of gastrointestinal epithelial cells and could be cleaved into soluble ACE2 via ADAM17. In the meantime, it mediates the transportation of amino acids and is responsible for the apelin peptides [shown in (C)]. However, it also promotes the SARS-CoV-2 entry into the host cells, increasing the difficulty in understanding its exact effects within the GIT and in the whole body.

FIGURE 2

ACE2 serves as a dominant link between the gut and other parts of the body. The expression level of ACE2 within the gut could interfere with the nutrient metabolism and result in alteration of the intestine microbes. Also as a pivotal ligand for the entry of SARS-CoV-2, it has an influence on the virus concentration. Moreover, the soluble form of ACE2 could also transmit to other organs and lead to disturbance of the physical condition. All three ways mentioned above are shown in the picture with explanation of different pathways.