Localization and secretion of BDNF in the hippocampus

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Abstracts / Neuroscience Research 71S (2011) e108–e415

showed immunoreactivity for Nestin, GFAP and Dcx. These results demonstrated that GDNF-pretreatment ameliorated the survival of NSCs following transplantation at least partly through suppression of cell apoptosis. doi:10.1016/j.neures.2011.07.592

P2-g12 Regulated processing/release of neuregulin-1 precursors in rat cortical neurons Yuriko Iwakura , Ran Wang, Kazuaki Araki, Hiroyuki Nawa Dep. of Mol. Neurosci., Brain Res. Inst., Niigata Univ., Niigata, Japan Neuregulin-1 (NRG-1) belongs to the family of epidermal growth factor (EGF) and is implicated in the regulation of glutamatergic transmission, GABAergic function and myelination. Recent genetic studies also indicate the association of this gene with a schizophrenia risk. Mature NRG1 is produced from its membrane-anchored precursors (type 1–3) through ectodomain shedding by methalloproteinases such as ADAMs. However, the regulation of NRG1 processing and release is poorly understood. We previously reported that the activation of dopamine receptors regulates processing and release of EGF precursors in striatal cultures. Here we examined NRG1 processing and release in cultured cortical and hippocampal neurons. Cultured neurons were challenged with various types of neurotransmitters for 30 min and culture supernatants were subjected to a two site ELISA for pan-NRG1 protein. Among the neurotransmitters examined, glutamate and acetylcholine triggered NRG1 release in a dose dependent manner, whereas dopamine stimulation had no effects. The acetylcholine-triggered release was attenuated by the glutamate receptor antagonists, CNQX and AP-5. These results suggest that glutamate neurotransmission has a regulatory role in NRG1 processing and release. Currently we are analyzing the difference of the NRG1 release/processing among type 1–3 NRG1 variants. Research fund: The Uehara Memorial Foundation. doi:10.1016/j.neures.2011.07.593

P2-g13 Localization and secretion of BDNF in the hippocampus Tomoya Matsumoto 1,3 , Sandra Dieni 2 , Martijn Dekkers 3 , Stefanie Rauskolb 3 , Mihai Ionescu 3 , Ruben Deogracias 3 , Eckart D. Gundelfinger 4 , Masami Kojima 5,6 , Sigrun Nestel 2 , Michael Frotscher 2 , Yves-Alain Barde 3 1 Dept. of Psychiatry and Neurosci., Grad. Sch. of Med. Sci., Hiroshima Univ., Hiroshima, Japan 2 Inst. Anatomy and Cell Biol., Univ. Freiburg, Freiburg, Germany 3 Biozentrum, Univ. Basel, Basel, Switzerland 4 Dept. Neurochem. and Mol. Biol., Leibniz Inst. for Neurobiol., Magdeburg, Germany 5 Biointerface Research Group, AIST, Ikeda, Japan 6 CREST, JST, Kawaguchi, Japan

Brain-derived neurotrophic factor (BDNF) is initially synthesized as a precursor protein (pro-BDNF) that is posttranslationally processed to (mature) BDNF. We previously used pulse-chase experiments with hippocampal neurons to show that this processing occurs rapidly in an intracellular compartment (Matsumoto et al., 2008 Nat. Neurosci.). The present study examined the distribution of BDNF immunoreactivity in the adult hippocampus by light and electron microscopy. Antibodies selectively reacting with BDNF or its pro-peptide stained the same sub-population of large secretory vesicles in presynaptic terminals, but they did not detect any specific signals in postsynaptic structures. Not only BDNF but also its pro-peptide were biochemically detected in hippocampal lysates, with a pro-BDNF:BDNF:BDNF pro-peptide ratio of about 1:9:9. These results suggest that in the hippocampus, both BDNF and its pro-peptide are transported to the axon terminals, possibly in the same vesicles. It is thus conceivable that both peptides may be secreted in an activity-dependent manner. doi:10.1016/j.neures.2011.07.594

P2-g14 Effects of prenatal exposure to diesel exhaust on cell number in the motor cortex of neonatal rat Hiroko Ochiai 1 Takeda 1,3

, Shinya

Yanagita 2,3 , Jiro

Kanemaru 1 , Ken

1

Faculty of Paumaceutial Science, Tokyo University of Science, Chiba, Japan Faculty of Science and Technology, Tokyo University of Science, Chiba, Japan 3 Research Center for Health Science of Nanoparticles 2

Several studies have shown that diesel exhaust (DE), one of the main causes of air pollution, has detrimental effects on cardiovascular, reproductive and immune function in addition to the central nerve system. We previously reported that prenatal exposure to DE impaired the nigrostriatal dopamin-

ergic systems and locomotor activity in postnatal rodents. In this study, we examined the effects of prenatal DE exposure on developmental changes in the motor cortex, which integrates the nigrostriatal dopaminergic systems, in neonatal rats. Pregnant SD rats were exposed to DE (1.0 mg DEP/cubic meter) in an inhalation chamber for 8 h/day from gestational days 2–18. We investigated cell number in the motor cortex at postnatal days 5, 7, 14, and 21 using BrdU immunohistochemistry. Furthermore, we investigated the effects of prenatal DE exposure on GDNF synthesis and secretion functions, which are crucial for regulation of neuronal cell number. The results showed that, in comparison to control rats, prenatal exposure to DE significantly increases the number of BrdU immunoreactive cells in the motor cortex of 5 and 7-dayold. The number of GDNF synthesis cells in the motor cortex of DE-exposed 5-day-old rats was significantly lower than in control rats. Furthermore, at 5 days, GDNF secretion levels of CSF in DE-exposed rats tended to be lower than in controls. These results indicate that prenatal exposure to DE affects cell number in the motor cortex during the neonatal period. Our findings suggest that cell number abnormality in the motor cortex could be a factor in the detrimental effects on locomotor activity induced by DE, and that proper development of brain may impaired when dams are exposed to DE. doi:10.1016/j.neures.2011.07.595

P2-g15 Biological roles of the BDNF pro-peptide in the nervous system Toshiyuki Mizui 1 , Koichi Uegaki 1,3 , Yasuyuki Ishikawa 2,3 , Tomoko Hara 1,3 , Masami Takahashi 3,4 , Sadao Shiosaka 2,3 , Chiaki Itami 5 , Haruko Kumanogoh 1,3,4 , Masami Kojima 1,3 1

Bio-Interface Research Group, HRI, AIST, Ikeda, Japan 2 Division of Structural Cell Biology, Nara Institute of Science and Technology, Ikoma, Japan 3 CREST, JST, Kawaguchi, Japan 4 Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Japan 5 Department of Physiology, Faculty of Medicine, Saitama Medical University, Moroyama, Japan The discovery of BDNF polymorphism Val66Met correlating with decreased memory performance focused attention on the BDNF pro-domain, but its biological role remains unclear. We find that the BDNF pro-peptide binds BDNF and inhibits its ability to modulate LTD. Interestingly, Val66Met polymorphism stabilized their binding and consequently slowed down the dissociation of BDNF. Conversely, the BDNF pro-peptide facilitated LTD on its own, suggesting that the pro-peptide is a new synaptic modulator. Research fund: KAKENHI (4034417), CREST. doi:10.1016/j.neures.2011.07.596

P2-g16 Alteration of BDNF expression in hippocampus of BRINP1-KO mice Miwako Kobayashi 1 , Makiko Miyake 1 , Makoto Motomiya 2 , Keizo Takao 3 , Toshiaki Koda 4 , Tsuyoshi Miyakawa 5 , Ichiro Matsuoka 1 1

Col. of Pharm. Sci., Matsuyama Univ., Matsuyama, Japan 2 Dep. of Ortho. Surgery, Grad. Sch. of Med., Hokkaido Univ., Sapporo, Japan 3 Ctr. for Genetic Analysis of Behavior, NIPS, Okazaki, Japan 4 Grad. Sch. of Life Sci., Hokkaido Univ., Sapporo, Japan 5 Div. of Systems Med. Sci., ICMS, Fujita Health Univ., Toyoake, Japan We have previously reported that BRINP (BMP- and Retinoic acid inducible neural specific protein) family genes are induced during the course of neuronal differentiation and continued to be expressed into adulthood. Ectopic expression of any of three BRINP genes results in cessation of cell-cycle progression in both normal fibroblastic cells (NIH-3T3) and ES-derived neural stem cells. Among the three family members, BRINP1 is most highly expressed in various brain regions including hippocampus in adult mouse. BRINP expression in adult hippocampus (dentate gyrus) is further upregulated by the increase of neural activity (intraperitoneal administration of kainic acid) in a similar manner to BDNF expression. To assess the physiological roles of BRINP1 gene in the nervous system, we have generated BRINP1-deficient (KO) mice. BRINP1-KO mice developed normally and did not show any significant alteration of the macroscopic brain morphology. However, BRINP1-KO mice administrated with kainic acid showed significant neurodegeneration in hippocampal CA3 region as visualized by Fluorojade staining. In addition, behavioral analysis of BRINP1-KO mice showed a significant increase of motility, poor social interaction and loss of concentration, while normal functions of spatial learning as well as sensory and neuromuscular transmission were maintained. In the present study, we found that the levels of BDNF-mRNA in adult hippocampus are significantly reduced in BRINP1-KO mice. These results suggest that the activity-induced BRINP1 in