Systemic analysis of tissue cells potentially vulnerable to SARS-CoV-2 infection by the protein-proofed single-cell RNA profiling of ACE2, TMPRSS2 and Furin proteases

Lulin Zhou; Zubiao Niu; Xiaoyi Jiang; Zhengrong Zhang; You Zheng; Zhongyi Wang; Yichao Zhu; Lihua Gao; Xiaoning Wang; Qiang Sun

To determine the mRNA expression level of ACE2, TMPRSS2 and Furin genes in distinct tissue cells, we systematically explored the established cell atlases of different organs and tissues. We found the expression level of ACE2, TMPRSS2 and Furin genes varied significantly across the tissues and organs analyzed ( Figure 4 ). And importantly, in certain tissues, these genes solely expressed in particular cell types. For example, the SARS-CoV-2 receptor ACE2 was mainly expressed in AT2 cells, and macrophages as well though much less, in the lung ( Figure 4A) , and cholangiocytes and hepatocytes in the human liver ( Figure 4C ), which is consistent with results of previous studies [21, 42] and confirmed our above analysis on protein expression. We further investigated the mRNA expression of TMPRSS2 and Furin proteases and confirmed that these genes were also expressed in the liver cholangiocytes, and lung macrophages and AT2 cells at the high level ( Figure 4A , C). Notably, in adult human ovary, we found that merely stroma cells expressed the ACE2 and Furin gene ( Figure 3G ). In addition, the spermatogonia as the male reproductive cell moderately expressed the ACE2 genes as well as Furin and TMPRSS2 ( Figure 4F ), while the Sertoli/Leydig cells express relatively low level of TMPRSS2, which is consistent with IHC results indicated above.