MicroRNAs in opioid pharmacology

Abstract

MicroRNAs (miRNA), a class of ~22-nucleotide RNA molecules, are important gene regulators that bind to the target sites of mRNAs to inhibit the gene expressions either through translational inhibition or mRNA destabilization. There are growing evidences that miRNAs have played several regulatory roles in opioid pharmacology. Like other research fields such as cancer biology, the area where numerous miRNAs are found to be involved in gene regulation, we assume that in opioid studies including research fields of drug additions and opioid receptor regulation, there may be more miRNAs waiting to be discovered. This review will summarize our current knowledge of miRNA functions on opioids biology and briefly describe future research directions of miRNAs related to opioids.

Fig. 1

A summary of proposed pathway for the regulation of miR-190 expression by fentanyl. This figure was adopted and redrawn from Zheng et al. (Zheng et al. 2010a).

Fig. 2

Potential target sites of miRNAs in MOR 3′-UTR from mouse strain C57BL/6 by bioinformatic analysis (MicroInspector: bioinfo.uni-plovdiv.bg/microinspector/) (Rusinov et al. 2005). Homology percentage between miRNA and target site is shown on right side of each sequence alignment. Cutoff value of free energy (fE) for binding is −27 (kcal/mol) and each fE is indicated on right side. Sequence alignments without fE value were either obtained from previous studies (He et al. 2010; Wu et al. 2008) or analyzed by other web-based softwares, such as TargetScan (http://www.targetscan.org/mmu_50/) (Lewis et al. 2005), miRBase (http://www.mirbase.org/) (Kozomara and Griffiths-Jones 2011), or miRDB (http://mirdb.org/miRDB/) (Wang and El Naqa 2008; Wang 2008).