MicroRNA-20a participates in the aerobic exercise-based prevention of coronary artery disease by targeting PTEN.

BACKGROUND: Exercise can reduce the coronary artery disease (CAD) incidence. MiRNA-20a has been reported to distinctly expressed after sustain physical activity. However, its expression and regulation pattern in CAD model with or without exercise has not been reported.

OBJECTIVE: In present study, we aim to investigate regulatory mechanism of miR-20a in exercise-associated reduced-CAD incidence and miR-20a-dependent signaling pathways.

METHODS: Eight weeks old male ApoE/LDLR double knock out mice were recruited for this study. CAD model was established in mice fed with or without western diet and cholesterol levels were measured using detection kit as well as fast protein liquid chromatography. Relative mRNA levels were determined using quantitative RT-PCR while the protein levels were analyzed using western blotting. Luciferase assay was used to determine the miRNA binding site on target genes. CCK-8 assay and flow cytometry (FCM) were used for assessing the proliferative and apoptotic rate.

RESULTS: Overall cholesterol level was significantly increased in CAD model group, compared to normal control group. Expression of miR-20 was significantly lower in CAD group where the VEGF and PTEN were upregulated, compared to non-CAD group. Increased miR-20a was induced after exercise in CAD model group, and miR-20a agomir group. Overexpression of miR-20a decreased the expression level of ET-1, TxA2, ANGII, PTEN and increased the eNOS, PGI2, and VEGF, at both transcriptional and translational levels. In vitro examination further confirmed these findings in human umbilical vein endothelial cells (HUVEC). MiR-20a specifically binds to the 3'UTR of PTEN and mediated the cell survival and proliferation through activating the PI3K/Akt signaling pathways.

CONCLUSION: MiRNA-20a may have great potential as therapeutic target for CAD, since its participation can induce alteration of functional genes as well as PTEN, which is specifically targeted by miR-20a, and promote the survival and proliferation of vein endothelial cells.