[Effect of miR-873 on cardiomyocyte apoptosis induced by hypoxia reoxygenation and its mechanism].

ABSTRACT

OBJECTIVE: To explore the role of miR-873 in cardiomyocyte injury induces by hypoxia reoxygenation (H/R) and its related mechanisms.
 Methods: H/R model was established by culturing mouse cardiac H9c2 cells in vitro, and miR-873 mimic was transfected. The experiments were divided into a control group, a H/R group, a negative control group and a miR-873 mimic group. The expression of miR-873 was measured using real-time PCR. The protein expression levels of egl-9 family hypoxia inducible factor 3 (Egln3), B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) were evaluated by Western blotting. Cell apoptosis ELISA kit and cysteine-containing, aspartate-specific proteases-3 (caspase-3) activity kit was used to detect cell apoptosis and caspase-3 activity, respectively. The targeting effect of miR-873 on Egln3 were examined by the dual luciferase report gene assay, and the experiments were divided into a negative control group, a Egln3 3'-untranslated regions (3'-UTR) WT group (WT group) and a Egln3 3'-UTR MUT group (MUT group). In order to further detect the effects of Egln3 on miR-873 mimics, the Egln3 overexpressed cells were constructed, and the experiments were divided into a H/R group, a H/R+miR-873 mimic group, a H/R+pcDNA3-Egln3 (pcEgln3) group and a H/R+ miR-873 mimic+pcEgln3 group.
 Results: Compared with the control group, the expression level of miR-873 was significantly decreased in the H/R group (P<0.05). Compared with the H/R group, H9c2 cell apoptosis, caspase-3 activity and the ratio of Bax/Bcl-2 were significantly reduced in the miR-873 mimic group (all P<0.05). Compared with the negative control group, the luciferase activity was significantly down-regulated in the WT group (P<0.05), while the luciferase activity was not significantly changed in the MUT group (P>0.05). In the over-expression experiment, compared with the H/R group, the cell apoptosis and the ratio of Bax/Bcl-2 were significantly reduced in the miR-873 mimic group (both P<0.05). Compared with miR-873 mimic group, the cell apoptosis and the ratio of Bax/Bcl-2 were significantly up-regulated in the H/R+pcEgln3 group and the H/R+miR-873 mimic+pcEgln3 group (all P<0.05).
 Conclusion: MiR-873 can inhibit H/R- induced apoptosis of cardiomyocyte via targeting Egln3.