The Role of hsa_circ_0076767 in Mitochondrial Injury During Myocardial Ischemia/Reperfusion: a Focus on miR-140-3p and the Hypoxia-Inducible Factor-1α/β-Catenin Pathway.

Abstract

OBJECTIVE: This study aimed to investigate whether hsa_circ_0076767 exacerbates mitochondrial injury during myocardial ischemia/reperfusion injury (MI/RI) by targeting miR-140-3p and directly inhibiting the hypoxia-inducible factor (HIF)-1α/β-catenin pathway. METHODS: MI/RI and hypoxia/reoxygenation (H/R) cell models were established. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to determine hsa_circ_0076767 expression in both the MI/RI models and to detect the subcellular localization of hsa_circ_0076767 and its responsiveness to ribonuclease R in HL-1 cells. A loss-of-function assay was performed to examine the function of hsa_circ_0076767 in cardiomyocyte mitochondrial and cardiac tissue injury following MI/RI. Hematoxylin-eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling staining were used to assess myocardial tissue injury and apoptosis of myocardial tissues in mice, respectively. hsa_circ_0076767 was assayed for cell viability using Cell Counting Kit-8, for apoptosis using flow cytometry, for mitochondrial membrane potential using JC-1, and for cellular adenosine triphosphate content using commercial kits. RT-qPCR and protein blotting were performed to detect gene expression. Dual-luciferase, ribonucleic acid pull-down, and fluorescence in situ hybridization co-localization assays were used to validate the interaction between hsa_circ_0076767 and miR-140-3p. Finally, the regulatory relationship between hsa_circ_0076767 and the HIF-1α/β-catenin pathway was verified. RESULTS: hsa_circ_0076767 was upregulated in myocardial tissues of MI/RI mice and H/R HL-1 cells. Silencing hsa_circ_007676767 ameliorated myocardial tissue injury, apoptosis, and mitochondrial damage in cardiomyocytes. hsa_circ_0076767 targets miR-140-3p. Moreover, hsa_circ_0076767 promoted mitochondrial injury by inhibiting the HIF-1α/β-catenin pathway. CONCLUSION: hsa_circ_0076767 targets miR-140-3p and directly inhibits the HIF-1α/β-catenin pathway, exacerbating mitochondrial damage in cardiomyocytes during MI/RI.