Hogan Eric M, Casserly Alison P, Scofield Michael D, Mou Zhongming, Zhao-Shea Rubing, Johnson Chris W, Tapper Andrew R, Gardner Paul D
Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts 01604, USA Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts 01604, USA.
Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts 01604, USA UMMS MD/PhD Program, University of Massachusetts Medical School, Worcester, Massachusetts 01604, USA.
RNA. 2014 Dec;20(12):1890-9. doi: 10.1261/rna.034066.112. Epub 2014 Oct 24.
Nicotine binds to and activates a family of ligand-gated ion channels, neuronal nicotinic acetylcholine receptors (nAChRs). Chronic nicotine exposure alters the expression of various nAChR subtypes, which likely contributes to nicotine dependence; however, the underlying mechanisms regulating these changes remain unclear. A growing body of evidence indicates that microRNAs (miRNAs) may be involved in nAChR regulation. Using bioinformatics, miRNA library screening, site-directed mutagenesis, and gene expression analysis, we have identified a limited number of miRNAs that functionally interact with the 3'-untranslated regions (3' UTRs) of mammalian neuronal nAChR subunit genes. In silico analyses revealed specific, evolutionarily conserved sites within the 3' UTRs through which the miRNAs regulate gene expression. Mutating these sites disrupted miRNA regulation confirming the in silico predictions. In addition, the miRNAs that target nAChR 3' UTRs are expressed in mouse brain and are regulated by chronic nicotine exposure. Furthermore, we show that expression of one of these miRNAs, miR-542-3p, is modulated by nicotine within the mesocorticolimbic reward pathway. Importantly, overexpression of miR-542-3p led to a decrease in the protein levels of its target, the nAChR β2 subunit. Bioinformatic analysis suggests that a number of the miRNAs play a general role in regulating cholinergic signaling. Our results provide evidence for a novel mode of nicotine-mediated regulation of the mammalian nAChR gene family.
尼古丁与一类配体门控离子通道——神经元烟碱型乙酰胆碱受体（nAChRs）结合并使其激活。长期接触尼古丁会改变各种nAChR亚型的表达，这可能导致尼古丁成瘾；然而，调节这些变化的潜在机制仍不清楚。越来越多的证据表明，微小RNA（miRNA）可能参与nAChR的调节。通过生物信息学、miRNA文库筛选、定点诱变和基因表达分析，我们鉴定出了数量有限的与哺乳动物神经元nAChR亚基基因的3'非翻译区（3'UTR）发生功能性相互作用的miRNA。计算机分析揭示了3'UTR内特定的、进化上保守的位点，miRNA通过这些位点调节基因表达。对这些位点进行诱变会破坏miRNA的调节作用，从而证实了计算机分析的预测结果。此外，靶向nAChR 3'UTR的miRNA在小鼠大脑中表达，并受到长期尼古丁暴露的调节。此外，我们发现这些miRNA之一，即miR-542-3p，在中脑边缘奖赏通路中受尼古丁调节。重要的是，miR-542-3p的过表达导致其靶标nAChR β2亚基的蛋白水平降低。生物信息学分析表明，许多miRNA在调节胆碱能信号传导中发挥着普遍作用。我们的研究结果为尼古丁介导的哺乳动物nAChR基因家族调节的新模式提供了证据。
