title: A Neuronal Transcriptome Response Involving Stress Pathways is Buffered by Neuronal microRNAs.
abstract: A single microRNA (miRNA) can inhibit a large number of mRNA transcripts. This widespread regulatory function has been experimentally demonstrated for a number of miRNAs. However, even when a multitude of targets is confirmed, function of a miRNA is frequently interpreted through a prism of a handful arbitrarily selected "interesting" targets. In this work we first show that hundreds of transcripts with target sites for two miRNAs expressed endogenously in neurons, miR-124 and miR-434-3p, are coordinately upregulated in a variety of neuronal stresses. This creates a landscape where these two miRNAs can exert their widespread inhibitory potential on stress-induced transcripts. Next, we experimentally demonstrate that overexpression of these two miRNAs indeed significantly inhibits expression of hundreds of stress-induced transcripts, thus confirming that these transcripts are enriched in true targets of examined miRNAs. A number of miRNAs were previously shown to have important roles in the regulation of stress responses, and our results suggest that these roles should be understood in light of a wide spread activation of miRNA targets during stresses. Importantly, a popular cationic lipid transfection reagent triggers such induction of miRNA targets. Therefore, when a transfection paradigm is employed to study miRNA function, the results of such studies should be interpreted with consideration for the inadvertent induction of miRNA targets.
authors.affiliation: Genes to Cognition Programme, Wellcome Trust Sanger Institute Cambridge, UK ; RNA Genomics Lab, European Molecular Biology Laboratory-European Bioinformatics Institute Cambridge, UK.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Manakov
authors.forename: Andrew
authors.initials: A
authors.lastname: Morton
authors.forename: Anton J
authors.initials: AJ
authors.lastname: Enright
authors.forename: Seth G N
authors.initials: SG
authors.lastname: Grant
keywords: buffering; miRNA; neuronal stress; primary neuronal culture; transcriptome