MiR-345-3p attenuates apoptosis and inflammation caused by oxidized low-density lipoprotein by targeting TRAF6 via TAK1/p38/NF-kB signaling in endothelial cells

Atherosclerosis is a risk factor for coronary heart disease and cerebral infarction. Recent reports show decreased miR-345-3p in apolipoprotein-E deficient mice. Our study aimed to determine the biological activities of miR-345-3p in endothelial cells exposed to oxidized low-density lipoprotein (oxLDL). Human umbilical vein endothelial cells were transfected with miR-345-3p mimic and then exposed to oxLDL. Expression of miR-345-3p was assayed using real time-qPCR (RT-qPCR). Cell viability, lactate dehydrogenase leakage, apoptosis, and protein levels of p53, cleaved-caspase 3 (c-caspase 3), Bax, and Bcl-2 were measured using a CCK-8 assay, LDH Cytotoxicity Assay Kit, Cell Death Detection ELISA Plus Kit, and western blot, respectively. Expression of tumor necrosis factor (TNF)-α, interleukin (IL)-6, ICAM-1, VCAM-1, and E-selectin also was determined. The binding between miR-345-3p and TNF-receptor-associated factor 6 (TRAF6) was validated by dual-luciferase reporter assay. The mRNA and protein levels of TRAF6 were determined by RT-qPCR and western blot. Expression levels of TAK1/p38/NF-κB pathway-related proteins were evaluated by western blot. The results showed that oxLDL reduced miR-345-3p expression. Upregulation of miR-345-3p impeded oxLDL-induced growth inhibition, lactate dehydrogenase leakage, apoptosis, and expression of TNF-α, IL-6, ICAM-1, VCAM-1, and E-selectin. A dual-luciferase reporter assay demonstrated that miR-345-3p directly targeted TRAF6. TRAF6 overexpression reversed the biological activities of miR-345-3p. MiR-345-3p inhibited activation of the TAK1/p38/NF-κB pathway by targeting TRAF6 in the presence of oxLDL. MiR-345-3p prevented oxLDL-induced apoptosis and inflammation through the TAK1/p38/NF-κB pathway via targeting TRAF6.