title: Brain-derived neurotrophic factor regulates the expression and synaptic delivery of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor subunits in hippocampal neurons.
abstract: Brain-derived neurotrophic factor (BDNF) plays an important role in synaptic plasticity in the hippocampus, but the mechanisms involved are not fully understood. The neurotrophin couples synaptic activation to changes in gene expression underlying long term potentiation and short term plasticity. Here we show that BDNF acutely up-regulates GluR1, GluR2, and GluR3 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor subunits in 7-day in vitro cultured hippocampal neurons. The increase in GluR1 and GluR2 protein levels in developing cultures was impaired by K252a, a tropomyosin-related [corrected] kinase (Trk) inhibitor, and by translation (emetine and anisomycin) and transcription (alpha-amanitine and actinomycin D) inhibitors [corrected] The increase in GluR1 and GluR2 protein levels in developing cultures was impaired by K252a, a Trk inhibitor, and by translation (emetine and anisomycin) and transcription (alpha-amanitine and actinomycin D) inhibitors. Accordingly, BDNF increased the mRNA levels for GluR1 and GluR2 subunits. Biotinylation studies showed that stimulation with BDNF for 30 min selectively increased the amount of GluR1 associated with the plasma membrane, and this effect was abrogated by emetine. Under the same conditions, BDNF induced GluR1 phosphorylation on Ser-831 through activation of protein kinase C and Ca(2+)-calmodulin-dependent protein kinase II. Chelation of endogenous extracellular BDNF with TrkB-IgG selectively decreased GluR1 protein levels in 14-day in vitro cultures of hippocampal neurons. Moreover, BDNF promoted synaptic delivery of homomeric GluR1 AMPA receptors in cultured organotypic slices, by a mechanism independent of NMDA receptor activation. Taken together, the results indicate that BDNF up-regulates the protein levels of AMPA receptor subunits in hippocampal neurons and induces the delivery of AMPA receptors to the synapse.
authors.affiliation: Center for Neuroscience and Cell Biology, Department of Zoology, University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: Margarida V
authors.initials: MV
authors.lastname: Caldeira
authors.forename: Carlos V
authors.initials: CV
authors.lastname: Melo
authors.forename: Daniela B
authors.initials: DB
authors.lastname: Pereira
authors.forename: Ricardo
authors.initials: R
authors.lastname: Carvalho
authors.forename: Susana S
authors.initials: SS
authors.lastname: Correia
authors.forename: Donald S
authors.initials: DS
authors.lastname: Backos
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Carvalho
authors.forename: José A
authors.initials: JA
authors.lastname: Esteban
authors.forename: Carlos B
authors.initials: CB
authors.lastname: Duarte
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002478:Cells, Cultured; D023902:Chromosome Pairing / Q000502:physiology; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D007074:Immunoglobulin G / Q000235:genetics / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D020813:Receptor, trkB / Q000235:genetics; D018091:Receptors, AMPA / Q000096:biosynthesis*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects* / Q000502:physiology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D007074:Immunoglobulin G; D018091:Receptors, AMPA; D011993:Recombinant Fusion Proteins; D020813:Receptor, trkB; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases