title: Inhibition of microRNA-1 attenuates hypoxia/re-oxygenation-induced apoptosis of cardiomyocytes by directly targeting Bcl-2 but not GADD45Beta.
abstract: MicroRNAs are small non-coding RNAs that are able to regulate gene expression and play important roles in some biological and pathological processes, including the myocardial ischemia/reperfusion (I/R) injury. Recent findings demonstrated that miR-1 exacerbated I/R-induced injury. This study was to investigate theanti-apoptotic property of miR-1 inhibition and the potential regulatory mechanism. Results showed miR-1 expression reduced in the heart of rats undergoing myocardial I/R and the cardiomyocytes receiving hypoxia/reoxygenation (H/R) injury, but the serum miR-1 expression increased. The targets of miR-1 were predicted by cDNA microarray, and Bcl-2 and GADD45β were selected as candidate targets. Western blot assay and qPCR showed Bcl-2 and GADD45β protein and mRNA expressions increased after I/R injury and H/R injury. Bcl-2 was a direct target of miR-1 as shown in previous studies. Luciferase assay and Western blot assay revealed GADD45β was a direct target of miR-1, and miR-1 suppressed GADD45β expression via binding to its 3'UTR. Furthermore, miR-1 inhibition increased Bcl-2 expression and reduced IA/AAR (infarct area/area at risk) ratio and cell apoptosis in rats undergoing myocardial I/R as well as in cardiomyocytes receiving H/R injury. Importantly, Bcl-2 knockdown restored these consequences following miR-1 inhibition. However, GADD45β knockdown reduced IA/AAR ratio and cell apoptosis in vivo and in vitro, but failed torestore above consequences after miR-1 inhibition. In conclusion miR-1 inhibition protects against H/R-induced apoptosis of myocytes by directly targeting Bcl-2 but not GADD45β.
authors.affiliation: Department of Pharmacology, School of Medicine, Shandong University Jinan 250100, China ; Department of Cardiology, The First Affiliated Hospital of Jiaxing University Jiaxing, 314000, China.
authors.forename: Changlin
authors.initials: C
authors.lastname: Zhai
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Jiaxing University Jiaxing, 314000, China.
authors.forename: Guanmin
authors.initials: G
authors.lastname: Tang
authors.affiliation: Department of Interventional Radiology, Yantai Economic and Technological Development Area Hospital Yantai 264006, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Peng
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Jiaxing University Jiaxing, 314000, China.
authors.forename: Huilin
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Jiaxing University Jiaxing, 314000, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Qian
authors.affiliation: Department of Pharmacology, School of Medicine, Shandong University Jinan 250100, China.
authors.forename: Shijun
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, School of Medicine, Shandong University Jinan 250100, China.
authors.forename: Jiankang
authors.initials: J
authors.lastname: Yao
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Jiaxing University Jiaxing, 314000, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Jiaxing University Jiaxing, 314000, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University Harbin 150086, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Pharmacology, School of Medicine, Shandong University Jinan 250100, China.
authors.forename: Xiumei
authors.initials: X
authors.lastname: Zhang
keywords: Bcl-2; apoptosis; cardiomyocytes; hypoxia/reoxygenation; microRNA-1