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Inhibition of microRNA-184 reduces H2O2-mediated cardiomyocyte injury via targeting FBXO28.

OBJECTIVE
Cardiovascular disease, especially coronary heart disease, is one of the diseases with the highest mortality. A large number of studies have found that microRNAs (miRNAs) are closely related to the occurrence and development of myocardial ischemia. This article mainly focused on the regulation of miR-184 on oxidative stress, inflammation, and apoptosis in myocardial infarction (MI).


MATERIALS AND METHODS
MiR-184 inhibitor or negative control (NC) were transfected into H9c2 cells. Then, H9c2 cells were treated with H2O2 to construct a cardiomyocyte injury model. H9c2 cells were divided into 4 groups: control group, H22O2 treatment group, H2O2 + NC group, and H2O2 + miR-184 inhibitor group. The oxidative stress of H9c2 cells was observed by the expression levels of SOD, ROS, and MDA in each group. The inflammatory response of H9c2 cells was reflected by the expression of TNF-α, IL-6, and IL-1β detected by ELISA kits. Western blot was used to detect the expression of cleaved Caspase-3, Bcl-2, Bax and F-box protein 28 (FBXO28). Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was utilized to detect miR-184 expression. TdT-mediated dUTP Nick-End Labeling (TUNEL) staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay were used to observe the apoptosis and cell viability. The Luciferase reporter experiment was used to prove whether miR-184 could target FBXO28.


RESULTS
MiR-184 expression was significantly increased in H2O2-induced H9c2 cell injury model. After H9c2 cells were transfected with miR-184 inhibitor to silence miR-184, the levels of ROS and MDA were markedly reduced, while the expression of SOD was greatly increased. At the same time, the expression of inflammatory factors was greatly reduced. Silencing miR-184 also increased Bcl-2 expression, and reduced the expression of cleaved Caspase-3 and Bax. In addition, compared with the H2O2 + NC group, the number of TUNEL positive cells in the H2O2 + miR-184 inhibitor group was also significantly reduced, and the cell viability was remarkably increased. The Luciferase reporter experiment proved that FBXO28 is a target gene of miR-184.


CONCLUSIONS
MiR-184 expression was increased in H2O2-treated H9c2 cells. Inhibition of miR-184 markedly inhibited oxidative stress and inflammation in cardiomyocytes, thereby inhibiting cardiomyocyte apoptosis, through the regulation of FBXO28.