title: By targeting Stat3 microRNA-17-5p promotes cardiomyocyte apoptosis in response to ischemia followed by reperfusion.
abstract: BACKGROUND
  Several studies have confirmed the role of microRNAs in regulating ischemia/reperfusion-induced cardiac injury (I/R-I). MiR-17-5p has been regarded as an oncomiR in the development of cancer. However, its potential role in cardiomyocytes has not been exploited. The aim of this study is to investigate the role of miR-17-5p in I/R-I and the underlying mechanism through targeting Stat3, a key surviving factor in cardiomyocytes.
  
  
  METHODS
  MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide) assay was used to detect the cell viability. ELISA and TUNEL were performed to measure apoptosis of neonatal rat ventricular cardiomyocytes (NRVCs). Infarct area was estimated by TTC (triphenyltetrazolium chloride) and Evans blue staining. Western blot analysis was employed to detect the Stat3 and p-Stat3 levels and real-time RT-PCR was used to quantify miR-17-5p level.
  
  
  RESULTS
  The miR-17-5p level was significantly up-regulated in I/R-I mice and in NRVCs under oxidative stress. Overexpression of miR-17-5p aggravated cardiomyocyte injury with reduced cell viability and enhanced apoptotic cell death induced by H2O2, whereas inhibition of miR-17-5p by its antisense AMO-17-5p abrogated the deleterious changes. Moreover, the locked nucleic acid-modified antisense (LNA-anti-miR-17-5p) markedly decreased the infarct area and apoptosis induced by I/R-I in mice. Furthermore, overexpression of miR-17-5p diminished the p-Stat3 level in response to H2O2. The results from Western blot analysis and luciferase reporter gene assay confirmed Stat3 as a target gene for miR-17-5p.
  
  
  CONCLUSIONS
  Upregulation of miR-17-5p promotes apoptosis induced by oxidative stress via targeting Stat3, accounting partially for I/R-I.
authors.affiliation: Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education; State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Harbin Medical University, Harbin, Heilongjiang, People's Republic of China.
authors.forename: Weijie
authors.initials: W
authors.lastname: Du
authors.forename: Zhenwei
authors.initials: Z
authors.lastname: Pan
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.forename: Leimin
authors.initials: L
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Haihai
authors.initials: H
authors.lastname: Liang
authors.forename: Chaoqian
authors.initials: C
authors.lastname: Xu
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yanping
authors.initials: Y
authors.lastname: Wu
authors.forename: Hongli
authors.initials: H
authors.lastname: Shan
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D006861:Hydrogen Peroxide / Q000633:toxicity; D020287:In Situ Nick-End Labeling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics*; D032383:Myocytes, Cardiac / Q000473:pathology*; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000473:pathology*; D050796:STAT3 Transcription Factor / Q000235:genetics*
chemical_list: D035683:MicroRNAs; C543614:Mirn17 microRNA, mouse; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; D006861:Hydrogen Peroxide