miRNAome analysis of the mammalian neuronal nicotinic acetylcholine receptor gene family

Abstract

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.

Identification of Differentially Expressed miRNAs in Colorado Potato Beetles (Leptinotarsa decemlineata (Say)) Exposed to Imidacloprid

“…These targets include select cytochrome P450s, ATP-binding cassette (ABC) transporters, and nAChRs [ 20 , 21 , 22 ]. Numerous examples exist that highlight the regulation of these imidacloprid-relevant targets by miRNAs [ 23 , 24 ]. While recent studies have started to associate miRNAs with insecticide resistance in various insects [ 14 , 25 , 26 ], no work so far has attempted to characterize modulated miRNAs in imidacloprid-treated CPBs.…”

Integrated miRNA-/mRNA-Seq of the Habenulo-Interpeduncular Circuit During Acute Nicotine Withdrawal

“…Quantitative reverse transcription-pcR (Rt-qpcR). RT-qPCR for miRNAs and mRNAs was performed as previously described 30 using TaqMan assays (ThermoFisher) for miR-106b-5p (Assay ID 000442), Pfn2 (Assay ID Mm01289572_m1), and Pfn1 (Assay ID Mm00726691_s1). Relative miRNA/gene expression was determined using the 2 −ΔΔCt method 60 .…”

“…However, little is known about the role of miRNAs in the mechanisms underlying nicotine dependence and withdrawal. Few studies have examined the regulation of miRNAs by nicotine in specific regions of the mammalian brain [29][30][31] . Previously, we showed that the expression of miRNAs predicted to target MREs within the 3′-UTRs of nAChR genes was altered after chronic nicotine treatment in whole brain or a specific brain region 30 .…”

“…Few studies have examined the regulation of miRNAs by nicotine in specific regions of the mammalian brain [29][30][31] . Previously, we showed that the expression of miRNAs predicted to target MREs within the 3′-UTRs of nAChR genes was altered after chronic nicotine treatment in whole brain or a specific brain region 30 . Nicotine has been reported to regulate miRNAs and mRNAs in the MHb, with microarrays detecting expression changes in mice self-administering nicotine 31 .…”

Comparison between dopaminergic and non-dopaminergic neurons in the VTA following chronic nicotine exposure during pregnancy

“…They are of particular interest because a single miRNA can regulate many factors affecting gene regulatory networks, thus affecting a large downstream response 21,22 . MiRNAs have been found to modulate the effects of abusive substances and to be involved in synaptic plasticity, developing connections, and other behaviors related to addition 17,23,24 .…”