Ryan Brigid, Logan Barbara J, Abraham Wickliffe C, Williams Joanna M
Department of Anatomy, University of Otago, Dunedin, New Zealand.
The Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
PLoS One. 2017 Jan 26;12(1):e0170407. doi: 10.1371/journal.pone.0170407. eCollection 2017.
Translation of synaptic mRNA contributes to alterations in the proteome necessary to consolidate long-term potentiation (LTP), a model of memory processes. Yet, how this process is controlled is not fully resolved. MicroRNAs are non-coding RNAs that negatively regulate gene expression by suppressing translation or promoting mRNA degradation. As specific microRNAs are synaptically located, we hypothesized that they are ideally suited to couple synaptic activation, translational regulation, and LTP persistence. The aim of this study was to identify LTP-regulated microRNAs at or near synapses. Accordingly, LTP was induced unilaterally at perforant path-dentate gyrus synapses in awake adult Sprague-Dawley rats. Five hours later, dentate gyrus middle molecular layer neuropil, containing potentiated synapses, was laser-microdissected. MicroRNA expression profiling, using TaqMan Low Density MicroRNA Microarrays (n = 4), identified eight regulated microRNAs. Subsequent individual TaqMan assays confirmed upregulation of miR-23a-3p (1.30 ± 0.10; p = 0.015) and miR-151-3p (1.17 ± 0.19; p = 0.045) in a second cohort (n = 7). Interestingly, bioinformatic analysis indicated that miR-151-3p and miR-23a-3p regulate synaptic reorganisation and transcription, respectively. In summary, we have demonstrated for the first time that microRNAs are regulated in isolated neuropil following LTP induction in vivo, supporting the hypothesis that synaptic, LTP-responsive microRNAs contribute to LTP persistence via regulation of the synaptic proteome.
突触mRNA的翻译有助于蛋白质组的改变，这是巩固长期增强（LTP，一种记忆过程模型）所必需的。然而，这一过程是如何被控制的尚未完全解决。微小RNA是一类非编码RNA，通过抑制翻译或促进mRNA降解来负向调节基因表达。由于特定的微小RNA定位于突触，我们推测它们非常适合将突触激活、翻译调控和LTP持续性联系起来。本研究的目的是鉴定突触处或其附近受LTP调节的微小RNA。因此，在清醒的成年Sprague-Dawley大鼠的穿通通路-齿状回突触处单侧诱导LTP。5小时后，对含有增强突触的齿状回中分子层神经纤维网进行激光显微切割。使用TaqMan低密度微小RNA微阵列（n = 4）进行微小RNA表达谱分析，鉴定出8种受调节的微小RNA。随后的单个TaqMan检测在第二个队列（n = 7）中证实了miR-23a-3p（1.30±0.10；p = 0.015）和miR-151-3p（1.17±0.19；p = 0.045）的上调。有趣的是，生物信息学分析表明，miR-151-3p和miR-23a-3p分别调节突触重组和转录。总之，我们首次证明了在体内LTP诱导后，微小RNA在分离的神经纤维网中受到调节，支持了突触LTP反应性微小RNA通过调节突触蛋白质组来促进LTP持续性的假说。
