Effect of oxidized low density lipoproteins and 17β-estrogen on mRNA expression of angiotensin-converting enzyme 2 in human vascular endothelial cells in vitro

AIM To investigate the effect of oxidized low density lipoprotein(ox-LDL)and 17β-estrogen (E2) on mRNA expression of angiotensin-converting enzyme 2 (ACE2) in human umbilical vein endothelial cells (HUVECs). METHODS HUVECs were treated respectively with various concentrations of ox-LDL (20,40,80 mg/L) and E2 (2,10,50 nmol/L) for 24 hours. In a combined experiment, HUVECs were treated with ox-LDL(40 mg/L) and various concentrations of E2 (2,10,50 nmol/L) for 24 hours. Changes in mRNA expression of ACE2 were determined with reverse transcription polymerase chain reaction (RT-PCR). RESULTS ox-LDL induced a concentration dependent down-regulation in mRNA expression of ACE2 and E2 induced a concentration dependent up-regulation in mRNA expression of ACE2. Compared with that in control group, treatment of HUVECs with ox-LDL at the concentration of 20,40,80 mg/L stimulated 0.74±0.08, 0.52±0.07 and 0.31±0.06 fold down-regulation in the ACE2 mRNA expression. Treatment of HUVECs with E2 at the concentration of 2, 10, 50 nmol/L stimulated 1.54±0.19, 2.43±0.28 and 2.89±0.26 fold up-regulation in the ACE2 mRNA expression. Compared with treatment with ox-LDL at the concentration of 40 mg/L group, the ACE2 mRNA expression of the combined group stimulated 1.95±0.38, 2.56±0.32 and 3.22±0.37 fold up-regulation. CONCLUSION ox-LDL down-regulates the mRNA expression of ACE2 and E2 up-regulates the mRNA expression of ACE2 in HUVECs in a concentration dependent manner. E2 inhibits the ox-LDL induced down-regulation of ACE2 mRNA expression in a dose-effect relationship.