Fig. 6
From: ApoE4 associated with severe COVID-19 outcomes via downregulation of ACE2 and imbalanced RAS pathway
ApoE4 downregulates ACE2 protein expression in vitro. A-D ACE2 protein levels in SH-SY5Y, HEK-293 T, A549 and HUVEC cells were examined by western blotting after transfection with 1 µg/ml plasmids expressing Flag, ApoE2-Flag, ApoE3-Flag or ApoE4-Flag for 48 h. The results were normalized to the expression of a-tubulin. The data are expressed as the mean ± SD. E Cells were stained with ACE2 (green) antibody and counterstained with DAPI (blue) after transfection with 1 µg/ml Flag, ApoE2-Flag, ApoE3-Flag or ApoE4-Flag plasmids for 48 h. The data are expressed as the mean ± SD. Statistical differences were evaluated by one-way ANOVA. Scale bars, 20 μm. *P < 0.05, **P < 0.01