Fig. 1.

The mRNA and protein levels of ACE2, CD147 and TMPRSS2 in human brain cells. (A–C) Total RNA was extracted from different cells and reverse transcribed, and the mRNA levels of ACE2, CD147 and TMPRSS2 genes was determined by qRT-PCR. Housekeeping gene GAPDH was used for normalization. Relative expression levels of different cells were compared with that of Calu3 cells. (D) Cell lysates were prepared from different cells and analyzed with Western blot using antibodies against ACE2, CD147 or TMPRSS2. β-Actin was used as the loading control. The relative levels of ACE2, CD147 and TMPRSS2 to those of β-actin were estimated by densitometry calculated. ∗∗p < 0.01; ∗∗∗p < 0.001; NS: not significant.