title: Down-regulation of microRNA-26b rescued hypoxia-induced apoptosis in cultured neonatal rat cardiac myocytes by regulating PTEN.
abstract: BACKGROUND
  Cardiomyocyte hypoxia causes cardiac hypertrophy and other major myocardial injuries. We investigated the molecular mechanism of microRNA-26b (miR-26b) in regulating hypoxia-induced apoptosis in rat neonatal cardiomyocytes.
  
  
  METHODS
  Neonatal rat cardiomyocytes was prepared in vitro and hypoxia was induced. Apoptotic cardiomyocytes were examined by TUNEL staining and the expression of miR-26b were monitored by qRT-PCR. The effect of mir-26b downregulation on hypoxia-induced apoptosis, or expression of PTEN in cardiomyocytes was monitored. PTEN was knocked down in cardiomyocytes by siRNA to further investigate its association with miR-26b.
  
  
  RESULTS
  Hypoxia induced severe apoptosis and upregulated miR-26b in neonatal rat cardiomyocytes in vitro. Down-regulation of miR-26b markedly ameliorated hypoxia-induced apoptosis and up-regulated PTEN. Luciferase reporter assay confirmed PTEN was directly targeted by miR-26b, and knocking down PTEN reduced cytotoxicity induced by miR-26b upregulation.
  
  
  CONCLUSIONS
  Downregulation of miR-26b protected cardiomyocytes from hypoxia-induced apoptosis, and the protective effect was very likely to be associated with PTEN regulation.
authors.affiliation: Department of Pediatrics, Lishui University Lishui, Zhejiang, 323000, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Pediatrics, Lishui University Lishui, Zhejiang, 323000, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Pediatrics, Lishui Maternal and Child Health Hospital Lishui, Zhejiang, 323000, China.
authors.forename: Qiaoqun
authors.initials: Q
authors.lastname: Dai
keywords: Cardiomyocytes; PTEN; hypoxia; miR-26b