Significant expression of FURIN and ACE2 on oral epithelial cells may facilitate the efficiency of 2019-nCov entry

Bing-peng Lin; Mei Zhong; Hong-bin Gao; Kai-bin Wu; Ming-xiao Liu; Chang Liu; Xin-hong Wang; Jian-ming Chen; Learn-han Lee; Cui-ling Qi; Lin-hu Ge; Li-jing Wang

As a co-expressed membrane endopeptidase of ACE2 receptor, FURIN play a central role in the human immunodeficiency virus type-1 (HIV-1) entering into the host cells through cleaving its envelope glycoprotein [12] . Genomic characterization of the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) have revealed that FURIN enzyme could activate the specific site of its spike protein [13] . Meanwhile, Li H. et. al revealed that a putative FURIN-cleavage site reported recently in the spike protein of SARS-CoV-2 may facilitate the virus-cell fusion, which can explain the virus transmission features [14] . In addition, Ma Y and co-authors found that presence of FURIN cleavage site, which is absent in other coronavirus, during the course of SARS-CoV-2 infection may cause some distinct clinical symptoms from SARS-CoV infection [15] . Similar results were also reported in Li X.'s study from China [16] . Hence, the expression and distribution of ACE2 and FURIN in human body were the key factors for the coronavirus to invade host cells. Furthermore, online single-cell sequence datasets analysis unveiled that FURIN was expressed in coronavirus's potential target organs, such as lung, heart, nose, rectum, colon, intestine and ileum [14] . However, information on the expression and distribution of ACE2 and FURIN in oral cavity were limited.