Effects of miR-23b on hypoxia-induced cardiomyocytes apoptosis

• Published in: Biomedicine & pharmacotherapy Vol. 96; pp. 812 - 817
• Main Authors: He, Weilai, Che, Hong, Jin, Chaolong, Ge, Shenglin
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.12.2017
• Subjects: Animals; Apoptosis; Apoptosis - physiology; bcl-2-Associated X Protein - metabolism; bcl-Associated Death Protein - metabolism; Caspase 3 - metabolism; Cell Proliferation - physiology; Cells, Cultured; Child; Chronic hypoxia; Congenital heart diseases; Female; Humans; Hypoxia - metabolism; In Situ Nick-End Labeling - methods; Male; MicroRNAs - metabolism; miR-23b; Myocytes, Cardiac - metabolism; Poly(ADP-ribose) Polymerases - metabolism; Proto-Oncogene Proteins c-bcl-2 - metabolism; Rats; Smad3; Up-Regulation - physiology; Smad3; Congenital heart diseases; miR-23b; Chronic hypoxia; Apoptosis
• ISSN: 0753-3322; 1950-6007
• DOI: 10.1016/j.biopha.2017.09.148

The aim of this study was to investigate the role of miR-23b in hypoxic cardiomyocytes and the potential mechanism. Myocardial samples of patients with cyanotic or acyanotic congenital heart disease (CHD) were collected to evaluate miR-23b expression. Agomir or antagomir of miR-23b was transfected into H9C2 cells. MTT, LDH assay and TUNEL staining were used to determine the cell proliferation and apoptosis under hypoxic conditions. Besides, the expression levels of cleaved-caspase-3, cleaved-PARP, Bad, Bcl-2 and Bax in hypoxic H9C2 cells were determined by western blot and qRT-PCR, respectively. Higher miR-23b expression levels were found in the patients with cyanotic CHD compared with the patients with acyanotic CHD. In addition, the expression of miR-23b was gradually up-regulated with prolonged hypoxia time in the H9C2 cells. Using MTT and LDH assays, cell growth was significantly decreased in the agomir group than that in the agomir-negative control (NC) group, while antagomir increased the cell growth. Using TUNEL staining and flow cytometry analysis, miR-23b promoted hypoxia-induced apoptosis. The expression levels of pro-apoptotic proteins, such as cleaved-caspase-3, cleaved-PARP and Bad, were significantly increased in the agomir group, while the Bcl-2 levels and Bcl-2/Bax ratio were decreased. Opposite tendency was observed in the antagomir group. Dual luciferase reporter assay and western blot analysis confirmed that Smad3 was a direct target of miR-23b. Over-expression of miR-23b may increase cardiomyocyte apoptosis and reduce cell growth under hypoxic conditions.