Effect of miRNA-223-3p Targeting Stromal Interaction Molecule 1 on Proliferation and Apoptosis of Hypoxia/Reoxygenation-Applied H9c2 Cardiomyocytes

Abstract

This study was established to determine the effect of miRNA-223-3p on the proliferation and apoptosis of hypoxia/reoxygenation-applied H9c2 cardiomyocytes and the associated mechanisms. A hypoxia/reoxygenation (H/R) model was established, with normal cells also used as a control. miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p plasmids were transfected into normally cultured cardiomyocytes, defined as the miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p groups. In addition, miRNA-223-3p was co-transfected into normally cultured cardiomyocytes with pcDNA3.1 and pcDNA3.1-STIM1 plasmids, followed by treatment with H/R for cells in the miR-NC and miR-223-3p groups, defined as the H/R+miRNA-NC, H/R+miRNA-223-3p, H/R+miRNA-223-3p+pcDNA3.1, and H/R+miRNA-223-3p+pcDNA3.1-STIM1 groups. A liposome method was adopted for assessing transfection. qRT-PCR was used to detect miRNA-223-3p expression, while western blotting was used to detect protein expression. MTT assay was used to detect cell viability, flow cytometry to detect apoptosis, and dual luciferase reporter gene assay to detect fluorescence activity. After H/R treatment, miR-223-3p, cyclin D1, and Bcl-2 expression of cardiomyocytes decreased, p21 and Bax expression significantly increased, cell activity decreased, and the apoptosis rate increased. miRNA-223-3p achieved the targeted regulation of STIM1 expression. miRNA-223-3p overexpression promoted the H/R-induced cardiomyocyte proliferation and inhibited cardiomyocyte apoptosis. STIM1 overexpression reversed the proliferation-promoting and apoptosis-inhibiting effects of miRNA-223-3p on cardiomyocytes treated with H/R. The findings show that miRNA-223-3p overexpression promotes H/R-induced cell proliferation, inhibits apoptosis, and protects H/R-induced cardiomyocytes from injury, via a mechanism probably associated with STIM1 expression. miRNA-223-3p thus provides a new target for treating cardiomyocyte injury.