Circular RNA Pum_0014 Targets miR-146a-5p/NF2 Axis to Regulate VEGF/PAK1 Pathway and Reduce H2O2-induced Cardiomyocyte Apoptosis.

Circular RNAs (circRNAs) have emerged as essential regulators in cardiovascular disease, including acute myocardial infarction (AMI). This study investigated the role of circRNA Pum1_0014 in myocardial infarction (MI) and its underlying mechanisms using an H9C2 cell model. Through Sanger sequencing, nucleic acid electrophoresis, RNase R, and transcriptional inhibition experiments, Pum1_0014 was identified as a novel circRNA. The cell localization of circRNA Pum1_0014 was detected by qPCR and fluorescence in situ hybridization, and the results revealed that circRNA Pum1_0014 is predominantly located in the cytoplasm. StarBase (URL: http://starbase.sysu.edu.cn/) and TargetScan (URL: https://www.targetscan.org/vert_80/) were used to predict circRNA Pum1_0014 targeting miRNAs and miRNA targeting mRNA, and the results identified miR-146a-5p as a potential target of Pum1_0014, which in turn targets NF2. The plasmid encoding the mutant circRNA Pum1_0014 or the 3'UTR mutant NF2 was constructed, and the interaction between Pum1_0014 and miR-146a-5p or miR-146a-5p and NF2 was detected by luciferase reporter gene assay. The results confirmed the interactions between Pum1_0014, miR-146a-5p, and NF2. In the MI cell model, upregulation of circRNA Pum1_0014 and NF2 and downregulation of miR-146a-5p were observed. Knockdown of circRNA Pum1_0014 inhibited NF2 expression and activated the VEGF/PAK1 pathway, reducing cardiomyocyte apoptosis. Conversely, inhibition of miR-146a-5p and overexpression of NF2 had opposite effects. These findings suggest that circRNA Pum1_0014 acts through the miR-146a-5p/NF2 axis to reduce cardiomyocyte apoptosis in MI via the VEGF/PAK1/NF2 pathway.