title: BMP2 promotes the differentiation of neural stem cells into dopaminergic neuronsin vitrovia miR-145-mediated upregulation of Nurr1 expression.
abstract: BACKGROUND
  Neural stem cells (NSCs) are pluripotent and self-renewing cells which could differentiate into diverse types of neural cells, such as dopaminergic (DA) neurons, the loss of which is the typical characteristic of Parkinson's disease (PD). This study aimed to examine the molecular mechanisms of BMP2-mediating NSCs differentiation into DA neurons.
  
  
  METHODS
  Different concentrations of BMP2 were used to induce the differentiation of NSCs into DA neurons, which were characterized by the number and the neurite lengths of tyrosine hydroxylase (TH)+ and dopamine transporter (DAT)+ neurons by immunocytochemistry. qRT-PCR and Western blot were performed to explore the expression of miR-145 and Nurr1. The methylation level of miR-145 promoter was examined by DNA methylation analyses. The regulation of miR-145 on Nurr1 was detected by Dual-Luciferase reporter assay.
  
  
  RESULTS
  The number of TH+ and DAT+ neurons were significantly increased in NSCs treated with 20 and 100 ng/ml of BMP2, as well as the neurite lengths of TH+ and DAT+ neurons. The reduced level of miR-145 and up-regulated Nurr1 were observed in NSCs induced by BMP2. The hypermethylation level of miR-145 promoter down-regulated the expression of miR-145 in NSCs pretreated with BMP2, which was regulated by DNMT3b. Luciferase reporter assay showed that Nurr1 was a direct target of miR-145. miR-145 overexpression restrained the differentiating effect of BMP2. Moreover, overexpression of Nurr1 abrogated this effect of miR-145 overexpression.
  
  
  CONCLUSIONS
  Our results showed that BMP2 promoted the differentiation of NSCs into DA neuronsin vitroand miR-145 and Nurr1 were involved in the neurotrophic effects of BMP2.
authors.affiliation: Neurological Department of Internal Medicine, Ningbo No. 2 Hospital Ningbo 315000, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Yan
authors.affiliation: Neurological Department of Internal Medicine, Ningbo No. 2 Hospital Ningbo 315000, China.
authors.forename: Zhao-Ying
authors.initials: ZY
authors.lastname: Chen
authors.affiliation: Neurological Department of Internal Medicine, Ningbo No. 2 Hospital Ningbo 315000, China.
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Chen
authors.affiliation: Neurological Department of Internal Medicine, Ningbo No. 2 Hospital Ningbo 315000, China.
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Chen
keywords: BMP2; Neural stem cells; Nurr1; differentiation; dopaminergic neurons; miR-145