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

To further determine the protein expression level of ACE2 in the oral mucosa, IHC experiments were performed. The first remarkable finding was that ACE2 was present in epithelial cells in all the tissues studied (Fig. 5) . Results indicated that the expression level of ACE2 protein was significantly higher in the lip, tongue, and buccal mucosa, especially the epithelial cells in the basal layer, although the mRNA expression level is not as high (Fig. 3) . The ACE2-postive cells in the gingival and palate tissue were limited. The corresponding gingiva and palate epithelial cells showed weak positive ACE2 staining. Also, we found that ACE2 expressed in fibroblasts and endothelial cells. These results indicate that oral epithelial cells were the potential targets of SARS-CoV-2. The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.18.047951 doi: bioRxiv preprint buccal and palate mucosa. These results indicated that SARS-CoV-2 might be able to infect oral tissues through the route of FURIN-mediated fusion with oral mucosal cell.