Regulation of miR-92a on vascular endothelial aging via mediating Nrf2-KEAP1-ARE signal pathway

H. Liu, H.-Y. Wu, W.-Y. Wang, Z.-L. Zhao, X.-Y. Liu, L.-Y. Wang

Department of International Medical Health Care Center, Zhengzhou Yihe Hospital Affiliated to Henan University, Zhengzhou, China. liuyiwanghb@163.com

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• Cardiology

OBJECTIVE: Various human aging-related diseases start with vascular aging, in which the aging of vascular endothelium is the first step to cause a structural and functional deficit of vascular endothelium, leading to vascular disorders. MicroRNA (miR) participates in various processes of body development and pathological processes via mediating cell proliferation, differentiation, and apoptosis. A previous study showed the correlation between cardiovascular disease and miR-92a, whose role and mechanism in vascular endothelial aging has not been reported.

MATERIALS AND METHODS: In vitro, cultured human umbilical vein endothelial cells (HUVECs) were prepared for the vascular endothelial aging model by using 10-6 mM angiotensin II. MiR-92a expression was examined. After transfecting with the miR-92a inhibitor, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was employed to describe cell proliferation, and the Caspase 3 activity assay kit was used to evaluate apoptosis activity. Myeloid peroxidase (MPO) and superoxidase (SOD) activity, plus reactive oxygen species (ROS) content were measured. Nrf2, KEAP1 and ARE mRNA expressions were measured by real-time PCR. Nuclear factor erythroid 2 p45 related factor 2 (Nrf2) protein level, inflammatory factors tumor necrosis factor α (TNF-α) and interleukin-2 (IL-2) were tested by western blot or enzyme-linked immunosorbent assay (ELISA).

RESULTS: In model group, miR-92a expression was elevated significantly compared to the control group (p < 0 .05). MiR-92a inhibitor transfection facilitated cell proliferation, decreased Caspase 3 activity, ROS or MPO, expressions of TNF-α, IL-2 and KEAP1, and enhanced SOD level and Nrf2, ARE expressions significantly compared to the model group (p < 0.05).

CONCLUSIONS: In aged vascular endothelium, miR-92a was up-regulated. Through inhibiting miR-92a expression and regulating Nrf2-KEAP1-ARE signal pathway, the oxidative stress reaction or inflammation can be suppressed, thus inhibiting endothelial apoptosis and facilitating cell proliferation.

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