Objective: We intended to study the specific function of microRNA-126-5p (miR-126-5p) in myocardial infarction (MI) and its underlying mechanisms of action in hypoxia-treated human umbilical vein endothelial cells (HUVECs).
Methods: Expression of miR-126-5p and its target gene homeodomain interacting protein kinase 2 (HIPK2) was evaluated by Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analysis. Flow cytometry and Cell Counting Kit-8 (CCK-8) assays were used to observe cell apoptosis and viability. Luciferase reporter gene assay was prepared for verifying the regulatory relationship between miR-126-5p and HIPK2. The levels of oxidative stress biomarkers (SOD, ROS, and MDA) were determined using commercial assay kits. The inflammatory response in the cells was analyzed by ELISA.
Results: MiR-126-5p expression upregulated in hypoxia-treated HUVECs compared to the untreated-HUVECs. Importantly, miR-126-5p knockdown suppressed hypoxia-induced cell apoptosis in HUVECs. In addition, the hypoxia-induced oxidative stress and inflammatory response were also significantly inhibited by miR-126-5p knockdown in HUVECs. Mechanically, miR-126-5p targets HIPK2. In rescue assay, HIPK2 knockdown reversed the inhibitory effect of miR-126-5p knockdown on hypoxia-induced cell apoptosis, oxidative stress, and inflammatory response in hypoxia-treated HUVECs.
Conclusion: MiR-126-5p targeted by HIPK2 regulates hypoxia induced endothelial injury in HUVECs, which indicated that miR-126-5p may be a molecular target for MI treatment.
Keywords: HIPK2; MI; amiR-126-5p; endothelial injury; hypoxia.
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