BACKGROUND: Endothelial cells are involved in vascular homeostasis, and endothelial cell dysfunction is involved in the pathogenesis of cardiovascular disease. This study aimed to investigate the effects of microRNA-154 in human umbilical vein endothelial cells (HUVECs) following injury induced by hydrogen peroxide (H₂O₂).

MATERIAL AND METHODS: Cell viability and apoptosis of HUVECs treated with H₂O₂ were measured. The expression of microRNA-154 was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell survival, caspase-3 activity, and the apoptosis rate were evaluated in H₂O₂-treated HUVECs cells after the upregulation and down-regulation of microRNA-154 expression. The interaction between microRNA-154 and Dickkopf WNT signaling pathway inhibitor 2 (DKK2) was predicted by bioinformatics analysis and was verified by luciferase reporter gene assay and Western blot. The effects of DKK2 short-interfering RNA (siRNA) on antioxidant injury in HUVECs cells were determined.

RESULTS: The survival rate of HUVECs exposed to H₂O₂ was significantly reduced and the apoptosis rate was significantly increased, and H₂O₂ significantly inhibited the expression of microRNA-154 in a dose-dependent manner. Overexpression of microRNA-154 increased cell survival, reduced the activity of caspase-3, and reduced cell apoptosis. Inhibition of microRNA-154 expression decreased cell survival, increased the activity of caspase-3, and promoted cell apoptosis. Luciferase reporter gene assay and Western blot showed that microRNA-154 interacted with the Wnt pathway molecule DKK2 in HUVECS. Also, DDK2 siRNA resulted in a similar protective effect on H₂O₂-treated HUVECs as overexpression of microRNA-154.

CONCLUSIONS: Oxidative injury in HUVECs was regulated by microRNA-154 targeting the Wnt/β-catenin signaling pathway.

Keywords: Cardiovascular Diseases, Cardiovascular System, endothelial cells, Apoptosis Regulatory Proteins, Intercellular Signaling Peptides and Proteins