title: Roles of MicroRNA-195 in cardiomyocyte apoptosis induced by myocardial ischemia-reperfusion injury.
abstract: This study aims to investigate microRNA-195 (miR-195) expression in myocardial ischaemia-reperfusion (I/R) injury and the roles of miR-195 in cardiomyocyte apoptosis though targeting Bcl-2. A mouse model of I/R injury was established. MiR- 195 expression levels were detected by real-time quantitative PCR (qPCR), and the cardiomyocyte apoptosis was detected by TUNEL assay. After cardiomyocytes isolated from neonatal rats and transfected with miR-195 mimic or inhibitor, the hypoxia/reoxygenation (H/R) injury model was established. Cardiomyocyte apoptosis and mitochondrial membrane potential were evaluated using flow cytometry. Bcl-2 and Bax mRNA expressions were detected by RT-PCR. Bcl-2, Bax and cytochrome c (Cyt-c) protein levels were determined by Western blot. Caspase-3 and caspase-9 activities were assessed by luciferase assay. Compared with the sham group, miR-195 expression levels and rate of cardiomyocyte apoptosis increased significantly in I/R group (both P < 0.05). Compared to H/R + negative control (NC) group, rate of cardiomyocyte apoptosis increased in H/R + miR-195 mimic group while decreased in H/R + miR-195 inhibitor group (both P <0.05). MiR-195 knockdown alleviated the loss of mitochondrial membrane potential (P <0.05). MiR-195 overexpression decreased Bcl-2 mRNA and protein expression, increased BaxmRNA and protein expression, Cyt-c protein expression and caspase-3 and caspase-9 activities (all P <0.05).While, downregulated MiR-195 increased Bcl-2 mRNA and protein expression, decreased Bax mRNA and protein expression, Cyt-c protein expression and caspase-3 and caspase-9 activities (all P < 0.05). Our study identified that miR-195 expression was upregulated in myocardial I/R injury, and miR-195 overexpression may promote cardiomyocyte apoptosis by targeting Bcl-2 and inducing mitochondrial apoptotic pathway.
authors.affiliation: Department of Emergency, Longnan Hospital of Daqing, Daqing 163001, People's Republic of China.gaochangkui789@163.com.
authors.forename: Chang-Kui
authors.initials: CK
authors.lastname: Gao
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.forename: Cheng-Ji
authors.initials: CJ
authors.lastname: Cui
authors.forename: Zhao-Guang
authors.initials: ZG
authors.lastname: Liang
authors.forename: Hong
authors.initials: H
authors.lastname: Yao
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D053148:Caspase 3 / Q000235:genetics; D053453:Caspase 9 / Q000235:genetics; D004789:Enzyme Activation; D015870:Gene Expression; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics / Q000502:physiology*; D015428:Myocardial Reperfusion Injury / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection
chemical_list: C569389:MIRN195a microRNA, mouse; C584139:MIRN195 microRNA, rat; D035683:MicroRNAs; D053148:Caspase 3; D053453:Caspase 9