Use of atorvastatin to inhibit hypoxia-induced myocardin expression

European Journal of Clinical Investigation, 04/18/2012

Chiu CZ et al. – Hypoxia in neonatal cardiomyocytes increases myocardin expression and ROS to cause cardiomyocyte hypertrophy, which can be prevented by atorvastatin by suppressing ROS and myocardin expression.

Methods

  • Cultured rat neonatal cardiomyocytes were subjected to hypoxia, and the expression of myocardin and ROS were evaluated.
  • Different signal transduction inhibitors, atorvastatin and N–acetylcysteine (NAC) were used to identify the pathways that inhibited myocardin expression and ROS.
  • Electrophoretic motility shift assay (EMSA) and luciferase assay were used to identify the binding of myocardin/serum response factor (SRF) and transcription to cardiomyocytes.
  • Cardiomyocyte hypertrophy was assessed by 3H–proline incorporation assay.

Results

  • Myocardin expression after hypoxia was inhibited by atorvastatin, RhoA/Rho kinase inhibitor (Y27632), extracellular signal–regulated kinase (ERK) small interfering RNA (siRNA)/ERK pathway inhibitor (PD98059), myocardin siRNA and NAC .
  • Bindings of myocardin/SRF, transcription of myocardin/SRF to cardiomyocytes, presence of myocardin in the nuclei of cardiomyocytes and protein synthesis after hypoxia were identified by EMSA, luciferase assay, confocal microscopy and 3H–proline assay and were suppressed by atorvastatin, Y27632, PD98059 and NAC.

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