title: [Micro RNA alteration after paraquat induced PC12 cells damage and regulatory mechanism of bcl-2].
abstract: OBJECTIVE
  To investigate the effects of paraquat on microRNA expressions in PCl2 cells, and to explore the regulatory mechanism of bcl-2.
  
  
  METHODS
  We used PC12 cells as a popular in vitro cell model system for characterizing the dopaminergic neuron. After 24 h treatment with different concentrations of PQ (0, 62.5 ümol/L), expression difference of microRNA was detected by microarray and examined by real-time quantitative PCR (RT-PCR). Cell apoptosis was analyzed with flow cytometry (FCM) and the relative levels of miR-34a, miR-Let-7e were measured by RT-RCR following the PCl2 cells treatment with 0, 62.5, 125, 250, 500, 1000 ümol/L PQ. Meanwhile, the protein expression of bcl-2 was evaluated by western blot according to forecasting targets analysis databases.
  
  
  RESULTS
  Cell viability decreased and cell apoptosis increased with increasing PQ concentrations (from 125 to 1000 ümol/L) in a dose-dependent manner (P < 0.05 or P < 0.01). MiRNA microarray showed that after 62.5 ümol/L PQ treatment, 11 miRNAs were significantly up-regulated while 8 miRNAs were down-regulated compared with control (P < 0.01). We chose miR-34a, miR-Let-7e which appeared most remarkable changes in microarray to examine by RT-PCR. It revealed that the level of miR-34a gradually ascended while miR-Let-7e declined after PQ treatment, which are accordant to the microarray results. The protein expression of bcl-2 treated with PQ significantly decreased compared with control and presented a negative correlation with the expression of miR-34a (P < 0.05 or P < 0.01).
  
  
  CONCLUSIONS
  The alteration of miRNAs expression may be involved in the neurotoxicity of PQ. Especially, mir-34a negatively regulated the level of bcl-2, and thus plays a key role in PQ-induced cell apoptosis.
authors.affiliation: School of Public Health, Ningxia Medical University, Ningxia 750004, China.
authors.forename: Min
authors.initials: M
authors.lastname: Huang
authors.forename: Dan
authors.initials: D
authors.lastname: Lou
authors.forename: Xiuli
authors.initials: X
authors.lastname: Chang
authors.affiliation: E-mail: zjzhou@shmu.edu.cn.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D035683:MicroRNAs / Q000235:genetics*; D016716:PC12 Cells; D010269:Paraquat / Q000633:toxicity*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats
chemical_list: C560944:MIRN34 microRNA, rat; C548145:MIRNLET7 microRNA, rat; D035683:MicroRNAs; D019253:Proto-Oncogene Proteins c-bcl-2; D010269:Paraquat