title: Truncated TrkB-T1 regulates the morphology of neocortical layer I astrocytes in adult rat brain slices.
abstract: By altering their morphology, astrocytes, including those involved in the maintenance and plasticity of neurons and in clearance of transmitter, play important roles in synaptic transmission; however, the mechanism that regulates the morphological plasticity of astrocytes remains unclear. Recently, we reported that T1, a subtype of TrkB (a family of BDNF-specific receptors), altered astrocytic morphology through the control of Rho GTPases in primary astrocyte cultures. In this study, we extended this observation to investigate acute neocortical slices from adult rats. T1 siRNA-expression vectors were electroporated into astrocytes in neocortical layer I of living rats. In both normal slices and control vector-electroporated slices, BDNF induced the elongation of the astrocytic processes and increased the branching of processes in slices after 1 h incubation. In contrast, in T1 siRNA-electroporated slices, no such significant morphological changes were observed in the astrocytes. In addition, the number of synaptophysin+ sites in contact with GFAP+ processes increased in a BDNF-T1-dependent manner without the increase in the total synaptophysin+ sites. Therefore, the present study provides evidence of the regulation of layer I astrocytic morphology by the BDNF-T1 signal in adult rat neocortical slices.
authors.affiliation: Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8502, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ohira
authors.forename: Nobuo
authors.initials: N
authors.lastname: Funatsu
authors.forename: Koichi J
authors.initials: KJ
authors.lastname: Homma
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Sahara
authors.forename: Motoharu
authors.initials: M
authors.lastname: Hayashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneko
authors.forename: Shun
authors.initials: S
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000187:drug effects; D004347:Drug Interactions; D018274:Electroporation / Q000379:methods; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005910:Glioma; D049452:Green Fluorescent Proteins / Q000378:metabolism; D020287:In Situ Nick-End Labeling / Q000379:methods; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D019579:Neocortex / Q000166:cytology*; D020932:Nerve Growth Factor / Q000494:pharmacology; D020033:Protein Isoforms / Q000737:chemistry / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020813:Receptor, trkB / Q000737:chemistry / Q000235:genetics / Q000502:physiology*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D005904:Glial Fibrillary Acidic Protein; D020033:Protein Isoforms; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; D020932:Nerve Growth Factor; D020813:Receptor, trkB