circRNA-miRNA Complex Participates in the Apoptosis of Myocardial Cells in Myocardial Ischemia/Reperfusion Injury.

Myocardial ischemia/reperfusion (I/R) injury is a common condition. This study aimed to investigate the potential mechanisms of circ_Ddx60 in the mouse model of I/R injury. Cardiac tissues were used to extract RNA for subsequent RNA sequencing analysis. Bioinformatic analysis was performed and circ_Ddx60 and Bcl2a1a (B cell leukemia/lymphoma 2 related protein A1a) were selected for further validation. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to detect the gene expression level. The effect of circ_Ddx60 on cardiac cell apoptosis was examined. The function of miR-302a-3p in cell apoptosis was further explored in circ_Ddx60-overexpressed HL-1 cells under hypoxia/reoxygenation (H/R) treatment. We have revealed a number of differentially expressed circRNAs and mRNAs between the I/R group and sham groups, with circ_Ddx60 being among them. Treatment of HL-1 cells with hypoxia/reoxygenation (H/R) led to an overexpression of circ_Ddx60, which then inhibited apoptosis and promoted the Bcl2a1a expression. Furthermore, circ_Ddx60 directly binds with miR-302a-3p, which could reverse the effect of circ_Ddx60 overexpression on cellular apoptosis and Bcl2a1a expression. Our study revealed that circ_Ddx60 inhibits apoptosis in myocardial cells by regulating the miR-302a-3p/Bcl2a1a axis, which provides novel insights into the prevention of myocardial I/R injury.