title: MiR-17-5p impairs trafficking of H-ERG K+ channel protein by targeting multiple er stress-related chaperones during chronic oxidative stress.
abstract: BACKGROUND
  To investigate if microRNAs (miRNAs) play a role in regulating h-ERG trafficking in the setting of chronic oxidative stress as a common deleterious factor for many cardiac disorders.
  
  
  METHODS
  We treated neonatal rat ventricular myocytes and HEK293 cells with stable expression of h-ERG with H2O2 for 12 h and 48 h. Expression of miR-17-5p seed miRNAs was quantified by real-time RT-PCR. Protein levels of chaperones and h-ERG trafficking were measured by Western blot analysis. Luciferase reporter gene assay was used to study miRNA and target interactions. Whole-cell patch-clamp techniques were employed to record h-ERG K(+) current.
  
  
  RESULTS
  H-ERG trafficking was impaired by H2O2 after 48 h treatment, accompanied by reciprocal changes of expression between miR-17-5p seed miRNAs and several chaperones (Hsp70, Hsc70, CANX, and Golga2), with the former upregulated and the latter downregulated. We established these chaperones as targets for miR-17-5p. Application miR-17-5p inhibitor rescued H2O2-induced impairment of h-ERG trafficking. Upregulation of endogenous by H2O2 or forced miR-17-5p expression either reduced h-ERG current. Sequestration of AP1 by its decoy molecule eliminated the upregulation of miR-17-5p, and ameliorated impairment of h-ERG trafficking.
  
  
  CONCLUSIONS
  Collectively, deregulation of the miR-17-5p seed family miRNAs can cause severe impairment of h-ERG trafficking through targeting multiple ER stress-related chaperones, and activation of AP1 likely accounts for the deleterious upregulation of these miRNAs, in the setting of prolonged duration of oxidative stress. These findings revealed the role of miRNAs in h-ERG trafficking, which may contribute to the cardiac electrical disturbances associated with oxidative stress.
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Weina
authors.initials: W
authors.lastname: Hu
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Lei
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Bing
authors.initials: B
authors.lastname: Yan
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Ren
authors.initials: R
authors.lastname: Zhang
authors.affiliation: The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China.
authors.forename: Yuanzhe
authors.initials: Y
authors.lastname: Jin
mesh_terms: D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology
chemical_list: D051638:Ether-A-Go-Go Potassium Channels; C496884:KCNH1 protein, human; C524941:MIRN17 microRNA, human; D035683:MicroRNAs; D018832:Molecular Chaperones; D016877:Oxidants; D006861:Hydrogen Peroxide