神経変性疾患 Neurodegenerative diseases
O2-9-2-1 HMGB1を用いた脊髄小脳変性症1型モデルマウス治療の試み HMGB1 as a therapeutic molecule candidate for spinocerebellar ataxia type1 (SCA1) ○田川一彦1, 伊藤日加瑠1, 岡澤均1 ○Hikaru Ito1, Kazuhiko Tagawa1, Hitoshi Okazawa1 東京医科歯科大学　難治疾患研究所　神経病理学分野1 Department of Neuropathology, Medical Research Institute, Tokyo Medical and Dental University1 DNA repair defends against naturally occurring or disease-associated DNA damage during the long lifespan of neurons, and is implicated in polyglutamine disease pathology. Nuclear dysfunction is a key feature of the pathology of polyglutamine diseases. Previously, we found that the reduction of nuclear HMGB1 protein level in the nucleoplasm associates with DNA damage and transcriptional repression in spinocerebellar ataxia type1 (SCA1) (Qi et al., Nat. Cell Biol., 2007). HMGB1 is an evolutionarily conserved non-histone chromatin-associated protein with key roles in the maintenance of nuclear homeostasis. However, questions remain regarding whether recovery of the amount of HMGB1 rescues SCA1 in vivo and which molecules mediate the HMGB1 dysfunction. Here we report that genetic overexpression of HMGB1 improved motor dysfunction and elongated lifespan in mutant Ataxin1 knock-in mice. Furthermore, AAV vector induced overexpression of HMGB1 improved motor dysfunction and SCA1 cerebellar pathology. These results collectively suggest that HMGB1 is a molecular target for therapeutics of spinocerebellar ataxia type1.	O2-9-2-2 小脳プルキンエ細胞におけるRNA結合タンパク質HuCの機能 RNA-binding protein HuC is required for maintenance of the axon in Purkinje cells ○岡野ジェイムス洋尚1, 角元恭子2, 吉田哲2, 長谷川実奈美1岡野栄之2 ○James Hirotaka Okano1, Kyoko Kakumoto2, Tetsu Yoshida2, Minami Hasegawa1, Robert Darnell3, Hideyuki Okano2 東京慈恵会医科大学　再生医学研究部1, 慶應義塾大学　医学部　生理学2, ロックフェラー大学3 Div Regen Med, Jikei Univ Sch of Med, Tokyo1, Dept Physiol, Keio Univ Sch of Med, Tokyo2, The Rockefeller Univ, NY3 Hu proteins (the neuronal Elav-like: nElavl) are the mammalian homologue of Drosophila Elav, an RNA-binding protein expressed in the nervous system. In embryonic brain, Hu family proteins (HuB/C/D) induce neuronal are widely expressed in all kind of neurons and its expression persists from early embryo to adulthood. HuC KO exhibited intentional tremor, gait abnormality and ataxia at 7 months of age. Prior to the onset, the axons of Purkinje cells underwent morphological change; swollen and retracted at the deep cerebellar nuclei, although the pathological changes were not observed during cerebellar development. Accumulation of mitochondria and APP in the swollen Purkinje axons indicates impaired axonal transport, however, Purkinje cell soma seemed to be intact even at 21 months of age. To identify HuC targets in adult cerebellum, we performed RIP-CHIP assay and isolated several candidate RNAs including Kinesin family members KIF3A and KIF3C which are known to be involved in the axonal transport. Protein level of KIF3A was significantly downregulated in HuC KO. Moreover, protein production of KIF3A and 3C was induced without changing their transcript levels by co-expression of HuC with full-length KIF cDNAs in culture cells. These results indicate that HuC regulates the expression of KIF3A and 3C by a post-transcriptional mechanism in vitro and in vivo. Furthermore, we used HITS-CLIP to determine the binding sites targeted by the Hu family proteins. Surprisingly, Hu protein binds preferentially to GU-rich sequences in vivo and in vitro, with secondary binding to AU-rich sequences. HuC or HuD null mice were used to validate the consequence of these binding events in the brain, demonstrating that they bind intronic sequences in a position dependent manner to regulate alternative splicing and to 3'UTR sequences to regulate mRNA levels.This research is supported by grants from JSPS
O2-9-2-3 球脊髄性筋萎縮症モデルにおけるイソフラボンの効果 Genistein, a natural product derived from soybeans, ameliorates polyglutamine-mediated motor neuron disease ○足立弘明1, 強強1, 黄哲1, 蒋月梅1, 勝野雅央1, 松本慎二郎1, 近藤直英1, 宮崎雄1, 飯田円1, 藤内玄規1, 祖父江元1 ○Hiroaki Adachi1, Qiang Qiang1, Zhe Huang1, Yue-Mei Jiang1, Masahisa Katsuno1, Shinjiro Matsumoto1, Naohide Kondo1, Yu Miyazaki1, Madoka Iida1, Genki Tohnai1, Gen Sobue1 名古屋大学大学院医学系研究科神経内科1 Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya1 Spinal and bulbar muscular atrophy (SBMA) is an inherited motor neuron disease caused by the expansion of a polyglutamine (polyQ) tract within the androgen receptor (AR) gene. The pathologic features of SBMA are motor neuron loss in the spinal cord and brainstem and diffuse nuclear accumulation and nuclear inclusions of mutant AR in residual motor neurons and certain visceral organs. AR-associated coregulator 70 (ARA70) was the first co-regulator of AR to be identified, and it has been shown to interact with AR and increase its protein stability. Here, we report that genistein, an isoflavone found in soy, disrupts the interaction between AR and ARA70 and promotes the degradation of mutant AR in neuronal cells and transgenic mouse models of SBMA. We also demonstrate that dietary genistein ameliorates behavioral abnormalities, improves spinal cord and muscle pathology, and decreases the amounts of monomeric AR and high-molecular-weight mutant AR protein aggregates in SBMA transgenic mice. Thus, genistein treatment may be a potential therapeutic approach for alleviating the symptoms of SBMA by disrupting the interactions between AR and ARA70.	O2-9-2-4 In vivo protein aggregation due to autophagy deficiency leads to abnormal psychiatric behaviours ○Kelvin Hui1, Akiko Watanabe1, Hiroshi Matsukawa1, Per Nilsson1, Hiroki Yoshise1, Takaomi Saido1, Shigeyoshi Itohara1, Takeo Yoshikawa1, Motomasa Tanaka1 RIKEN Brain Science Institute1 Though genetic association studies have demonstrated that psychiatric disorders such as schizophrenia and autistic spectrum disorder (ASD) are highly hereditary, unlike neurodegenerative diseases such as Alzheimer's and Huntington's Diseases, no clear genetic linkages have been established for these psychiatric disorders. We hypothesized that similar to neurodegenerative diseases, protein misfolding, aggregation and cross seeding may form the molecular basis from which psychiatric disorders arise. In order to test this hypothesis, we first examined the aggregation status of proteins either encoded within copy number variant (CNV) regions or known to be associated with diseases by in silico and in vitro approaches via overexpression in cell lines and primary neurons. Through these preliminary experiments, we found that a number of such disease-associated proteins to be highly aggregation-prone. In order to examine the physiologic relevance of these findings, we have focused our analysis on a mouse model deficient in a major pathway involved in protein homeostasis (autophagy). By conditionally deleting Atg7 in forebrain excitatory neurons, we have observed that a number of these disease-associated proteins form detergent-insoluble p62- and ubiquitin-positive aggregates in vivo. Interestingly, we have also demonstrated that these animals show defects in long-term potentiation (LTP) and other vital electrophysiological parameters, consistent with the significant reduction in dendritic spine densities observed in affected neurons. Furthermore, Atg7 conditional knockout mice were also observed to exhibit abnormal psychiatric behaviours. We hope that further examination of this autophagy-deficient mouse model will establish protein misfolding/aggregation as a novel pathogenic mechanism for psychiatric disorders and offer an innovative therapeutic approach to treat these debilitating diseases.

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