title: Expression profiling of synaptic microRNAs from the adult rat brain identifies regional differences and seizure-induced dynamic modulation.
abstract: In recent years, microRNAs or miRNAs have been proposed to target neuronal mRNAs localized near the synapse, exerting a pivotal role in modulating local protein synthesis, and presumably affecting adaptive mechanisms such as synaptic plasticity. In the present study we have characterized the distribution of miRNAs in five regions of the adult mammalian brain and compared the relative abundance between total fractions and purified synaptoneurosomes (SN), using three different methodologies. The results show selective enrichment or depletion of some miRNAs when comparing total versus SN fractions. These miRNAs were different for each brain region explored. Changes in distribution could not be attributed to simple diffusion or to a targeting sequence inside the miRNAs. In silico analysis suggest that the differences in distribution may be related to the preferential concentration of synaptically localized mRNA targeted by the miRNAs. These results favor a model of co-transport of the miRNA-mRNA complex to the synapse, although further studies are required to validate this hypothesis. Using an in vivo model for increasing excitatory activity in the cortex and the hippocampus indicates that the distribution of some miRNAs can be modulated by enhanced neuronal (epileptogenic) activity. All these results demonstrate the dynamic modulation in the local distribution of miRNAs from the adult brain, which may play key roles in controlling localized protein synthesis at the synapse.
authors.affiliation: Departamento de Biología Celular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, DF México. pichardo@email.ifc.unam.mx
authors.forename: Israel
authors.initials: I
authors.lastname: Pichardo-Casas
authors.forename: Loyal A
authors.initials: LA
authors.lastname: Goff
authors.forename: Mavis R
authors.initials: MR
authors.lastname: Swerdel
authors.forename: Alejandro
authors.initials: A
authors.lastname: Athie
authors.forename: Jonathan
authors.initials: J
authors.lastname: Davila
authors.forename: Mariana
authors.initials: M
authors.lastname: Ramos-Brossier
authors.forename: Martha
authors.initials: M
authors.lastname: Lapid-Volosin
authors.forename: Wilma J
authors.initials: WJ
authors.lastname: Friedman
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Hart
authors.forename: Luis
authors.initials: L
authors.lastname: Vaca
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D020869:Gene Expression Profiling; D006624:Hippocampus / Q000378:metabolism; D007608:Kainic Acid; D035683:MicroRNAs / Q000032:analysis* / Q000378:metabolism; D057907:Post-Synaptic Density / Q000378:metabolism; D016548:Prosencephalon / Q000378:metabolism; D051381:Rats; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism*; D013569:Synapses
chemical_list: D035683:MicroRNAs; D007608:Kainic Acid