MeCP2 in the Nucleus Accumbens Contributes to Neural and Behavioral Responses to Psychostimulants

MeCP2 is a methyl-DNA binding transcriptional regulator that contributes to the development and function of CNS synapses; however the requirement for MeCP2 in stimulus-regulated behavioral plasticity is not fully understood. Here we show that acute viral manipulation of MeCP2 expression in the Nucleus Accumbens (NAc) bidirectionally modulates amphetamine (AMPH)-induced conditioned place preference. Hypomorphic Mecp2 mutant mice have an increased number of NAc GABAergic synapses and show deficient AMPH-induced structural plasticity of NAc dendritic spines. Furthermore these mice show deficient plasticity of striatal immediate early gene inducibility following repeated AMPH administration. Intriguingly, psychostimulants induce phosphorylation of MeCP2 at Ser421, a site that regulates MeCP2's function as a repressor. Phosphorylation is selectively induced in GABAergic interneurons of the NAc, and its extent strongly predicts the degree of behavioral sensitization. These data reveal novel roles for MeCP2 in both mesolimbocortical circuit development and in the regulation of psychostimulant-induced behaviors.