[Effect and related mechanism of microRNA-181 attenuates oxidized low density lipoprotein induced vascular...

Objective: To observe the expression level of microRNA-181 (miR-181) and importin-α3 in oxidized low density lipoprotein (ox-LDL) induced vascular endothelial cell injury models, and explore the effect and mechanism of miR-181 on endothelial cell injury. Methods: Human vein endothelial cell line CRL-1730 were cultured and vascular endothelial cell injury model was established by intervention with ox-LDL. The cells were divided into control group (intervened by double distilled water), low-dose group (intervened by 10 μg/ml ox-LDL) and high-dose group (intervened by 20 μg/ml ox-LDL). In addition, cells of low-dose group were divided into miR-181 mimic group (miR-181 mimic was transfected) and mimic control group (miR-181 mimic control was transfected). Cell viabilities, mRNA and protein expression level of interleukin-6 (IL-6), miR-181, importin-α3, and nuclear transcription factor-κB (NF-κB) were measured by methyl thiazolyl tetrazolium (MTT), real-time PCR and Western blot, respectively. Results: (1) The cell viabilities in low-dose group and high-dose group were lower than control group (0.207±0.012 and 0.204±0.007 vs. 0.323±0.018, all P<0.01). The relative IL-6 mRNA expression in low-dose group and high-dose group were higher than control group (1.24±0.16 and 1.36±0.23 vs. 0.22±0.03, all P<0.01). The relative miR-181 mRNA expression in low-dose group and high-dose group were lower than control group (0.91±0.11 and 0.88±0.07 vs. 2.20±0.13, all P<0.01). The relative importin-α3 mRNA expression in low-dose group and high-dose group were higher than control group (1.23±0.22 and 0.55±0.03 vs. 0.44±0.06, all P<0.01). The relative NF-κB mRNA expression in low-dose group and high-dose group were higher than control group (1.67±0.34 and 0.41±0.11 vs. 0.11±0.04, all P<0.01). The relative importin-α3 protein expression in low-dose group and high-dose group were higher than control group (1.44±0.23 and 1.31±0.22 vs. 0.29±0.08, all P<0.01). The relative NF-κB protein expression in low-dose group and high-dose group were higher than control group (0.43±0.05 and 0.37±0.04 vs. 0.16±0.03, all P<0.01). (2)The cell viabilities in miR-181 mimic group was higher than in mimic control group (0.262±0.008 vs. 0.211±0.021, P<0.01). The relative miR-181 mRNA expression level in miR-181 mimic group was higher than in mimic control group (4.23±0.34 vs. 0.88±0.16, P<0.01). The relative importin-α3 mRNA expression level in miR-181 mimic group was lower than in mimic control group (0.24±0.03 vs. 1.08±0.13, P<0.01). The relative NF-κB mRNA expression level was lower in miR-181 mimic group than in mimic control group (0.13±0.03 vs. 0.51±0.06, P<0.01). The relative importin-α3 protein expression level was lower in miR-181 mimic group than in mimic control group (0.34±0.06 vs. 1.67±0.26, P<0.01). The relative NF-κB protein expression level was lower in miR-181 mimic group than in mimic control group (0.43±0.02 vs. 1.53±0.36, P<0.01). Conclusions: Lower miR-181 expression but higher importin-α3 and its downstream NF-κB signaling are associated with ox-LDL induced vascular endothelial cell injury and up-regulation of miR-181 could alleviate ox-LDL induced vascular endothelial cell injury possibly via importin-α3/NF-κB pathway.