title: MicroRNA-125b protects against myocardial ischaemia/reperfusion injury via targeting p53-mediated apoptotic signalling and TRAF6.
abstract: OBJECTIVE
  The present study examined the role of microRNA-125b (miR-125b) in myocardial ischaemia/reperfusion (I/R) injury. We constructed lentivirus-expressing miR-125b (LmiR-125b) and developed transgenic mice with overexpression of miR-125b.
  
  
  RESULTS
  LmiR-125b was transfected into mouse hearts through the right common carotid artery. Lentivirus vector (LmiR-Con) served as vector control. Untreated mice served as I/R control. Sham operation served as sham control. Seven days after transfection, the hearts were subjected to ischaemia (45 min) followed by reperfusion (4 h). Myocardial infarct size was analysed by 2,3,5-triphenyltetrazolium chloride staining. In separate experiments, hearts were subjected to ischaemia (45 min) followed by reperfusion for up to 7 days. Cardiac function was measured by echocardiography before, as well as 3 and 7 days after myocardial I/R. Increased expression of miR-125b significantly decreased I/R-induced myocardial infarct size by 60% and prevented I/R-induced decreases in ejection fraction (EF%) and fractional shortening (%FS). Transgenic mice with overexpression of miR-125b also showed the protection against myocardial I/R injury. Increased expression of miR-125b attenuated I/R-induced myocardial apoptosis and caspase-3/7 and -8 activities. Western blot showed that increased expression of miR-125b suppresses p53 and Bak1 expression in the myocardium. In addition, transfection of LmiR-125b decreased the levels of TNF receptor-associated factor 6 (TRAF6) and prevented I/R-induced NF-κB activation.
  
  
  CONCLUSIONS
  miR-125 protects the myocardium from I/R injury by preventing p53-mediated apoptotic signalling and suppressing TRAF6-mediated NF-κB activation.
authors.affiliation: Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Campus Box 70575, Johnson City, TN 37614-0575, USA.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Campus Box 70575, Johnson City, TN 37614-0575, USA.
authors.forename: Tuanzhu
authors.initials: T
authors.lastname: Ha
authors.affiliation: Animal Model Research Center, Nanjing University, Nanjing 210093, China.
authors.forename: Jianghuan
authors.initials: J
authors.lastname: Zou
authors.affiliation: Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Campus Box 70575, Johnson City, TN 37614-0575, USA.
authors.forename: Danyang
authors.initials: D
authors.lastname: Ren
authors.affiliation: Department of Geriatrics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Campus Box 70575, Johnson City, TN 37614-0575, USA.
authors.forename: Xia
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Biometry and Medical Computing, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA.
authors.forename: John
authors.initials: J
authors.lastname: Kalbfleisch
authors.affiliation: Animal Model Research Center, Nanjing University, Nanjing 210093, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Campus Box 70575, Johnson City, TN 37614-0575, USA.
authors.forename: David
authors.initials: D
authors.lastname: Williams
authors.affiliation: Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Campus Box 70575, Johnson City, TN 37614-0575, USA li@etsu.edu.
authors.forename: Chuanfu
authors.initials: C
authors.lastname: Li
mesh_terms: D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000502:physiology; D002478:Cells, Cultured; D016086:Lentivirus / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000502:physiology*; D009203:Myocardial Infarction / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology; D020556:Neutrophil Infiltration; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*; D048029:TNF Receptor-Associated Factor 6 / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000032:analysis
chemical_list: C494773:Bak1 protein, mouse; D035683:MicroRNAs; C527468:Mirn125 microRNA, mouse; D016328:NF-kappa B; D048029:TNF Receptor-Associated Factor 6; D016159:Tumor Suppressor Protein p53; D050998:bcl-2 Homologous Antagonist-Killer Protein; D020169:Caspases
keywords: Apoptosis; MicroRNA-125b; Myocardial I/R; NF-κB; p53