近日，国际著名杂志Journal of Cell Science在线刊登了上海生科院健康所研究人员的最新研究成果“miR-132 regulates the differentiation of dopamine neurons by directly targeting Nurr1 expression，”文章中，研究者发现了miroRNA调节多巴胺能神经元分化的新机制。
众所周知，中脑多巴胺能神经元的退行性死亡是帕金森病的最显著特征，了解其发育的分子生物学机制对探索帕金森病的发病机理以及治疗帕金森病都有着至关重要。然而，对于胚胎干细胞向多巴胺能神经元的发育过程的机制至今还不清楚。
健康所神经基因组博士研究生杨德华等在乐卫东研究员的指导下通过对于胚胎干细胞向多巴胺能神经元的发育过程中microRNA表达谱的变化分析发现了一些新的microRNA， 并且鉴定了其中一个miR-132在多巴胺能神经元发育的过程中表达显著变化. 进一步研究表明miR-132能通过直接靶向Nurr1从而调节胚胎干细胞向多巴胺能神经元的分化。该研究在国际上首次详细阐述了miR-132作为胚胎干细胞向多巴胺能神经元的调节作用和分子机制，对于帕金森病的发病机制的了解和未来以胚胎干细胞分化为多巴胺能神经元的细胞治疗帕金森疾病提供了重要理论依据和应用价值。
乐卫东教授长期以来一直在探索转录因子Nurr1的功能机制， 他领导的研究组第一次发现了 Nurr1是多巴胺能神经元的最重要的调控因子。同时博士研究生衡鑫在乐教授指导下， 得到最新的研究成果表明，Nurr1通过转录调节轴突导向基因TopIIβ影响了多巴胺能神经元的轴突生长，研究结果发表在本期的Molecular Neurodegeneration上。
该工作得到了国家自然科学基金委及科技部973项目的经费支持。（生物谷Bioon.com）
doi:10.1242/jcs.086421
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miR-132 regulates the differentiation of dopamine neurons by directly targeting Nurr1 expression
Dehua Yang*, Ting Li*, Yi Wang, Yuanjia Tang, Huijuan Cui, Yu Tang, Xiaojie Zhang, Degui Chen, Nan Shen and Weidong Le‡
Although it is well established that embryonic stem (ES) cells have the potential to differentiate into dopamine neurons, the molecular basis of this process, particularly the role of microRNAs (miRNAs), remains largely unknown. Here we report that miR-132 plays a key role in the differentiation of dopamine neurons by directly regulating the expression of Nurr1. First, we constructed a mouse ES cell line CGR8, which stably expresses GFP under the tyrosine hydroxylase (TH)-promoter, so the TH-positive neurons could be easily sorted out by a fluorescence-activated cell sorter (FACS). Then, we performed a miRNA array analysis in the purified TH-positive neurons and found that 45 of 585 miRNAs have expression level change >5 fold during dopamine neuron differentiation. Among the 45 miRNAs, we were particularly interested in miR-132 because this miRNA has been reported as being highly expressed in neurons and having a potential role in neurodegenerative diseases. We found that the direct down-regulation of endogenous miR-132 induced by miR-132 antisense oligonucleotide (miR-132-ASO) promoted the differentiation of TH-positive neurons, while ectopic expression of miR-132 in ES cells reduced the number of differentiated TH-positive neurons but did not change the total number of differentiated neurons. Furthermore, we documented that miR-132-ASO could significantly reverse the miR-132-mediated suppression of TH-positive neuron differentiation. Moreover, through bioinformatics assay we identified Nurr1 gene as a potential molecular target of miR-132. Using luciferase-reporter assay and Western blot analysis, we demonstrated that miR-132 could directly regulate the expression of Nurr1. Collectively, our data provide the first evidence that miR-132 is an important molecule regulating ES cell differentiation into dopamine neurons by directly targeting Nurr1 expression.
