MiR-218 regulates heroin seeking behavior by targeting Mecp2

Noncoding RNAs, especially microRNAs (miRNAs) have been implicated in the regulation of neuronal functions, such as learning, cognition and memory formation. However, the particular miRNAs involved in drug-induced behavioral plasticity are largely unknown. Here we report a novel regulator, miR-218, that inhibits heroin-induced behavioral plasticity. Network propagation-based method revealed several miRNAs that play key roles in drug-addiction, among which, miR-218 was decreased in nucleus accumbens (NAc) after chronic exposure to heroin. Lentiviral overexpression of miR-218 in NAc could inhibit heroin-induced reinforcement in both conditioning place preference (CPP) test and heroin self-administration (SA) experiment. Luciferase activity assay indicated miR-218 could regulate neuroplasticity related genes and directly target Mecp2 3’UTR. Consistently, Mecp2-/y mice exhibited reduced heroin seeking behavior in CPP test. These data reveal a functional role of miR-218 and its target, Mecp2, in the regulation of heroin-induced behavioral plasticity. Microarray screening was carried out to identify miRNAs responsive to chronic administration of heroin. Arrays used were miRCURY LNA microRNA Array, v.11.0 - hsa, mmu & rno.