title: Downregulation of microRNA-19b contributes to angiotensin II-induced overexpression of connective tissue growth factor in cardiomyocytes.
abstract: OBJECTIVE
  The present study was designed to decipher the molecular mechanisms underlying angiotensin (Ang) II-induced overexpression of connective tissue growth factor (CTGF) in cultured cardiomyocytes.
  
  
  METHODS
  Cardiomyocytes isolated from 1- to 3-day-old neonatal rats were cultured and treated with 100 nM Ang II with or without pretreatment with 10 nM telmisartan, an Ang II type 1 receptor antagonist. The role of microRNA (miR)-19b in the regulation of Ang II-induced CTGF expression was evaluated in cultured cardiomyocytes with quantitative real-time reverse transcription polymerase chain reaction and Western blot analysis.
  
  
  RESULTS
  We provide several lines of evidence to show that miR-19b contributes to the Ang II-induced overexpression of CTGF in cultured cardiomyocytes. Firstly, administration of Ang II decreased the level of miR-19b dramatically (p < 0.05 vs. control), which was abolished by telmisartan. Secondly, Ang II increased the level of CTGF significantly (p < 0.05 vs. control), which was also prevented by pretreatment with telmisartan. Thirdly, overexpression of miR-19b decreased CTGF levels (p < 0.05 vs. control). Finally, transfection of miR-19b into cardiomyocytes prevented the upregulation of CTGF induced by Ang II.
  
  
  CONCLUSIONS
  Downregulation of miR-19b contributes to Ang II-induced overexpression of CTGF in cultured cardiomyocytes.
authors.affiliation: Texas Heart Institute, Houston, Tex., USA.
authors.forename: Song
authors.initials: S
authors.lastname: Gao
authors.forename: Tie-Wen
authors.initials: TW
authors.lastname: Liu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Jiao
authors.forename: Jun
authors.initials: J
authors.lastname: Cai
authors.forename: Hong-Jie
authors.initials: HJ
authors.lastname: Chi
authors.forename: Xin-Chun
authors.initials: XC
authors.lastname: Yang
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D055513:Connective Tissue Growth Factor / Q000378:metabolism*; D015536:Down-Regulation; D035683:MicroRNAs / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D015854:Up-Regulation
chemical_list: C586754:MIRN19 microRNA, rat; D035683:MicroRNAs; D012333:RNA, Messenger; D000804:Angiotensin II; D055513:Connective Tissue Growth Factor