MicroRNA-146b inhibition augments hypoxia-induced cardiomyocyte apoptosis

• Published in: Molecular medicine reports Vol. 12; no. 5; pp. 6903 - 6910
• Main Authors: LI, JING-WEI, HE, SI-YI, FENG, ZE-ZHOU, ZHAO, LIANG, JIA, WEI-KUN, LIU, PENG, ZHU, YUN, JIAN, ZHAO, XIAO, YING-BIN
• Format: Journal Article
• Language: English
• Published: Greece D.A. Spandidos 01.11.2015; Spandidos Publications; Spandidos Publications UK Ltd
• Subjects: Animals; Annexin V; Apoptosis; Bcl-2 protein; Cardiomyocytes; Caspase; Caspase-3; Cell Hypoxia; Cell Line; Cells, Cultured; Congenital diseases; Coronary artery disease; Cytokines; DNA nucleotidylexotransferase; Families & family life; Gene expression; Genetic aspects; Health aspects; Heart; Heart cells; Heart Defects, Congenital - complications; Heart Defects, Congenital - genetics; Heart Defects, Congenital - pathology; Heart diseases; Humans; Hypoxia; Hypoxia - complications; Hypoxia - genetics; Hypoxia - pathology; Infant; Kinases; L-Lactate dehydrogenase; Laboratories; Lactic acid; Membrane permeability; MicroRNA; microRNA-146b; MicroRNAs - antagonists & inhibitors; MicroRNAs - genetics; miRNA; Mitochondria; Mortality; Myocytes, Cardiac - cytology; Myocytes, Cardiac - metabolism; Myocytes, Cardiac - pathology; Polymerase chain reaction; Propidium iodide; Rats; Reverse transcription; Ribonuclease L; RNase L; Rodents; Studies; Surgery; Transfection; Up-Regulation; United States > US; China
• ISSN: 1791-2997; 1791-3004
• DOI: 10.3892/mmr.2015.4333

MicroRNAs (miRs) regulate a number of physiological and pathological processes, including myocardial chronic hypoxia. Previous studies revealed that the expression of miR-146b is increased in vitro and in vivo following the induction of hypoxia. In the present study, the role of miR-146b in hypoxic cardiomyocytes, and the mechanisms underlying its activity, were investigated. The expression of miR-146b was measured in tissue samples from patients with congenital heart disease by reverse transcription-quantitative polymerase chain reaction. The rat H9c2 cardiomyocyte cell line was transfected with an miR-146b inhibitor or the experimental controls, and the cells were maintained under hypoxic conditions for 72 h. The expression of miR-146b increased following the induction of hypoxia. Transfection with the miR-146b inhibitor enhanced the release of lactate dehydrogenase and increased hypoxia-induced apoptosis, as determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling, Hoechst 33258 staining, JC-1 assay (measuring mitochondrial membrane permeability) and annexin V/propidium iodide analysis. A decreased expression of Bcl-2 was observed, whereas the expression levels of cleaved-caspase 3 and Bax were increased. Western blot analysis and a dual luciferase reporter assay confirmed that ribonuclease L is a direct target of miR-146b. Furthermore, inhibition of miR-146b increased the activation of nuclear factor-κB and signal transducer and activator of transcription 3. In conclusion, the inhibition of miR-146b may increase hypoxia-induced cardiomyocyte apoptosis.