Original Paper

Apoptosis

, Volume 17, Issue 4, pp 410-423

Overexpression of microRNA-378 attenuates ischemia-induced apoptosis by inhibiting caspase-3 expression in cardiac myocytes

  • Ji FangAffiliated withDepartment of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University
  • , Xiao-Wei SongAffiliated withDepartment of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University
  • , Jing TianAffiliated withDepartment of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University
  • , Hu-Yan ChenAffiliated withDepartment of Physiology and Neurobiology, Basic Medical College, Ningxia Medical University
  • , Dong-Feng LiAffiliated withDepartment of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University
  • , Jian-Fei WangAffiliated withDepartment of Physiology and Neurobiology, Basic Medical College, Ningxia Medical University
  • , An-Jing RenAffiliated withDepartment of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University
  • , Wen-Jun YuanAffiliated withDepartment of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical UniversityDepartment of Physiology and Neurobiology, Basic Medical College, Ningxia Medical University
  • , Li LinAffiliated withDepartment of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University Email author 

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Abstract

MicroRNAs (miRNAs) are a novel class of powerful, endogenous regulators of gene expression. In an intact rat model of myocardial ischemia caused by coronary artery ligation, this study identified 17 miRNAs that changed more than 1.5-fold in the myocardium subjected to 4-h ischemia. Using miRNA microarray analysis, most of these aberrantly expressed miRNAs were confirmed by quantitative RT-PCR. MiR-378, a significantly down-regulated miRNA, was selected for further function study. In serum deprived rat H9c2 cardiomyocytes exposed to hypoxia (1% O2), miR-378 expression was down-regulated as well. The overexpression of miR-378 resulting from miR-378 mimic transfection significantly enhanced cell viability, reduced lactate dehydrogenase release, and inhibited apoptosis and necrosis. By contrast, miR-378 deficiency resulting from miR-378 inhibitor transfection aggravated the hypoxia-induced apoptosis and cell injury. In accordance, miR-378 inhibitor caused significant apoptosis and cell injury to cardiomyocytes cultured under normoxia. Using bioinformatic algorithms, caspase-3, a key apoptosis executioner, was predicted as a putative target of miR-378. The quantitative RT-PCR showed no effects of miR-378 mimic or inhibitor on caspase-3 mRNA level. However, the amount of caspase-3 proteins was reduced by miR-378 mimic, whereas increased by miR-378 inhibitor. Furthermore, the luciferase reporter assay confirmed caspase-3 to be a target of miR-378, and the apoptosis and cell injury caused by miR-378 inhibitor in both normoxic and hypoxic cells were abolished by a caspase-3 inhibitor. This study first showed that miR-378 inhibited caspase-3 expression and attenuated ischemic injury in cardiomyocytes. It may represent a potential novel treatment for apoptosis and ischemic heart disease.

Keywords

MicroRNA Myocardial ischemia Hypoxia Apoptosis Cardiomyocytes