一般口演（Oral）

Oral Parkinson's Disease 一般口演パーキンソン病

7月28日（日）11:50～12:05　第8会場（朱鷺メッセ　3F　303+304） 4O-08a2-1 ミトコンドリア由来の細胞質dsDNAはパーキンソン病における細胞毒性と神経変性を惹起する Hideaki Matsui（松井秀彰）新潟大学研究推進機構超域学術院脳病態解析分野 Although mitochondrial dysfunction has been implicated in Parkinson's disease (PD), its contribution to the pathogenesis remains unknown. Mutations in the genes encoding mitochondrial proteins, including Parkin and PTEN-induced kinase 1 (PINK1), cause familial PD. Autophagy and/or lysosomal dysfunction are also common features of PD models and patients. Here, cytosolic dsDNA of mitochondrial origin that escapes from lysosomal degradation induces cytotoxicity in cultured cells and PD phenotypes in vivo. The depletion of PINK1, glucocerebrosidase (GBA) or cation-transporting ATPase 13A2 (ATP13A2) or the overexpression of α-synuclein increases the cytosolic mitochondrial DNA content and induces type I interferon (IFN) responses and cell death in cultured cell lines. These phenotypes are rescued by the overexpression of molecular-X which can degrade mitochondrial DNA, or by the depletion of molecular-Y which works as a sensor for cytosolic dsDNA of mitochondrial origin. Importantly, gba mutant zebrafish, which show movement disorders and dopaminergic cell loss, also show increased levels of cytosolic dsDNA puncta and cytosolic DNA responses. Movement disorders and dopaminergic cell loss in gba mutant zebrafish are rescued by X. Furthermore, the levels of Y are markedly elevated in the brains of patients with PD. Lewy bodies, a pathological hallmark of PD, present in postmortem brain tissues contain mitochondrial DNA within their cores. These results support a common causative role for the cytosolic leakage of mitochondrial DNA in PD pathogenesis.		7月28日（日）12:05～12:20　第8会場（朱鷺メッセ　3F　303+304） 4O-08a2-2 CHCHD2の変異はα-シヌクリンにプリオン様の凝集活性を付与し、α-シヌクリンの凝集化を促進する Hongrui Meng（孟紅蕊）¹，Aya Ikeda（池田彩）²，Kenya Nishioka（西岡健弥）²，Masashi Takanashi（高梨雅史）²，Tsuyoshi Inoshita（井下強）³，Kahori Shiba-Fukushima（柴福嶋佳保里）³，Ayami Okuzumi（奥住文美）²，Manabu Funayama（船山学）⁴，Yuzuru Imai（今居讓）^2,5，Nobutaka Hattori（服部信孝）^1,2,3,4,5 ¹順天堂大学院医神経変性・認知症講座 ²順天堂大学医学部附属順天堂医院脳神経科 ³順天堂大学院医学研究科多発性硬化症および神経難病治療・研究講座 ⁴順天堂大学院医学研究科老人性疾患病態・治療研究センター ⁵順天堂大学院医学研究科　パーキンソン病病態解明研究講座 Parkinson's disease (PD) is a movement disorder caused by the degeneration of dopaminergic neurons in the substantia nigra pars compacta. Pathological hallmark of PD is the accumulation of Lewy bodies, intraneuronal inclusions composed primarily of α-synuclein and ubiquitin, in the affected regions. Recently, mutations in a mitochondrial protein CHCHD2 are linked to an autosomal dominant form of familial PD and its novel risk variants have been identified in Lewy body disorders (LBD). Our previous report indicates that CHCHD2 regulates the mitochondria respiratory complex and that mutations of CHCHD2 results in destabilization of cytochrome c and elevated production of ROS, leading to apoptotic cell death and oxidative stress. We found widespread Lewy body pathology in the brain tissue of a PD patient with a CHCHD2 mutation. Biochemically, phosphorylated α-synuclein and CHCHD2 appeared in the sarkosyl-insoluble fractions and the insoluble α-synuclein had a prion-like seeding property. Histochemical analysis revealed that CHCHD2 co-localize with α- synuclein in Lewy bodies. In Drosophila, the dopaminergic expression of α-synuclein combined with endogenous CHCHD2 null or co-expression of the human CHCHD2 PD mutation in the CHCHD2 null genetic background accelerated the accumulation of sarkosyl-insoluble α-synuclein and polyubiquitinated proteins, leading to age-dependent neuron loss, locomotor deficiency and reduced lifespan. Moreover, mutations of CHCHD2 caused its mislocalization and compromised autophagy pathway in an aging-dependent manner, leading to compensatory activation of the proteasome pathway. Our work suggests that PD-associated mutants have a loss-of-function property and provides the explanation for how CHCHD2 mutations affect α-synuclein stability in PD.

7月28日（日）12:20～12:35　第8会場（朱鷺メッセ　3F　303+304） 4O-08a2-3 USP10はα-シヌクレイン凝集およびレビー小体を誘導するアグリソームの形成に重要な因子である Masahiko Takahashi（高橋雅彦）¹，Hiroki Kitaura（北浦弘樹）²，Akiyoshi Kakita（柿田明美）²，Taichi Kakihana（垣花太一）¹，Yoshinori Katsuragi（葛城美徳）¹，Masaaki Nameta（行田正晃）³，Yuriko Iwakura（岩倉百合子）⁴，Hiroyuki Nawa（那波宏之）⁴，Masaya Higuchi（樋口雅也）⁵，Masaaki Komatsu（小松雅明）⁶，Masahiro Fujii（藤井雅寛）¹ ¹新潟大院医歯学総合研ウイルス学 ²新潟大脳研病理学 ³新潟大電子顕微鏡共同研究室 ⁴新潟大脳研基礎神経科学分子神経生物 ⁵金沢医大微生物学 ⁶順天大院　医器官細胞生理学 Background Parkinson's disease (PD) is a progressive neurodegenerative disease, characterized by loss of midbrain dopamine neurons and conditions of movement disorders. α-synuclein plays a causative role in PD, and α-synuclein aggregates in the brain lesions, called Lewy bodies, are the hallmark pathology of PD. In cultured cells, the treatment of proteasome inhibitor induces α-synuclein aggregates called aggresomes. Aggresome and Lewy body have similar constituent proteins, and accumulating evidence suggests that Lewy body is formed through an aggresome-related mechanism. In this study, we show an evidence that ubiquitin-specific protease 10 (USP10) plays critical roles in aggresome formation, Lewy body formation and aggresome-mediated inhibition of apoptosis. Result A proteasome inhibitor (MG-132) treatment of cultured cells (HeLa and Neuro-2a cells) induced one big HDAC6/p62 (aggresome markers)-double positive aggresome at the perinuclear cytoplasmic region, and this aggresome colocalized with USP10. Before treatment, USP10 was diffusely localized at the cytoplasm. Knockdown of USP10 (USP10-KD) in HeLa cells reduced aggresome formation, and augmented MG-132-induced apoptosis. In USP10-KD cells, many p62-positive/HDAC6-negative aggregates throughout the cytoplasm were detected. These results indicated that USP10 promotes transport of p62-aggregates to aggresome and inhibits apoptosis by aggresome formation. USP10-KD and p62-KD showed that USP10 and p62 cooperatively inhibit apoptosis. USP10 interacted with the ubiquitin receptor p62, and the interaction augmented p62-dependent ubiquitinated protein aggregation and aggresome formation. In cells overexpressing α-synuclein, α-synuclein was localized at aggresomes. In PD patients, USP10 and phosphorylated α-synuclein co-localized at Lewy bodies. The amount of USP10 was increased in PD patients. Multiple system atrophy (MSA) is another type of synucleinopathy, forming α-synuclein-positive inclusion called oligodendroglial cytoplasmic inclusion (GCI). In MSA patients, USP10 was not colocalized with GCI, due to the low expression of USP10 in oligodendroglia. Conclusion Our study suggested that USP10 promotes aggresome formation to induce α-synuclein aggregation and Lewy body, and that USP10 might play a role in formation of distinct α-synuclein-positive inclusions in PD and MSA.		7月28日（日）12:35～12:50　第8会場（朱鷺メッセ　3F　303+304） 4O-08a2-4 USP10 promotes tau aggregation through stress granule formation in neuronal cells Svetlana Piatnitskaia（Piatnitskaia Svetlana）¹，Masahiko Takahashi（Takahashi Masahiko）¹，Hiroki Kitaura（Kitaura Hiroki）²，Yoshinori Katsuragi（Katsuragi Yoshinori）¹，Taichi Kakihana（Kakihana Taichi）¹，Akiyoshi Kakita（Kakita Akiyoshi）²，Yuriko Iwakura（Iwakura Yuriko）³，Hiroyuki Nawa（Nawa Hiroyuki）³，Takeshi Miura（Miura Takeshi）⁴，Takeshi Ikeuchi（Ikeuchi Takeshi）⁴，Toshifumi Hara（Hara Toshifumi）⁵，Masahiro Fujii（Fujii Masahiro）¹ ¹Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan ²Department of Pathology Brain Research Institute , Niigata Univirsity, Niigata, Japan ³Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan ⁴Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata, Japan. ⁵Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya, Japan Background Aggregation and accumulation of Tau protein in neurons of brain lesions is a hallmark pathology of Alzheimer's disease (AD). The RNA-binding protein TIA1 initiates Tau aggregation by inducing the formation of stress granules (SGs) containing Tau, and then promotes Tau-induced neuronal cell toxicity in cultured cells and AD-model mice. However, how TIA1 and SGs initiate Tau aggregation remains unclear. Ubiquitin-specific protease 10 (USP10) is a component of SGs, and it promotes SG formation and inhibits apoptosis induced by a SG inducer (arsenite). We examined whether USP10 plays a role in Tau-positive SG formation in neuronal cells. Methods 1. HT22 is a mouse neuronal cells. To quantify Tau-positive SG formation (Tau-SG), HT22 cells were treated with a proteasome inhibitor (MG-132), and SG formation was evaluated by immunostaining with anti-Tau, anti-TIA1 and anti-USP10 antibodies. TIA1 and USP10 are markers of SGs. 2. To examine the function of USP10 in SGs formation, we established USP10 knockdown HT22 cells by USP10 shRNA. The amount of USP10 was measured by western blot analysis. 3. To examine the role of USP10 in Tau-SG formation, HT22 cells were transfected with the plasmid encoding HA-tagged USP10 or USP10C424A (deubiquitinase defective mutant), and SG formation was analyzed by an immunostaining with anti-Tau, anti-TIA1 and anti-HA antibody. 4. Localization and expression of phosphoryalted-Tau and USP10 in AD brain samples (temporal cortex) was examined by an immunohistochemical analysis with anti-USP10 and anti-phosphorylated Tau (AT8) antibody . Results We found that ubiquitin-specific protease 10 (USP10) is a critical factor for the formation of Tau/TIA1-positive SGs. Proteasome inhibition, TIA1-overexpression or Tau-overexpression in HT22 neuronal cells induced the formation of Tau/TIA1-positive SGs, and the formations were severely attenuated by depletion of USP10. The overexpression of USP10 without stress stimuli in HT22 cells induced TIA1/Tau/USP10-triple-positive SGs. USP10 mutants indicated that deubiquitinase activity of USP10 is dispensable for TIA1/Tau/USP10-triple-positive SGs formation. In AD brain lesions (temporal cortex), USP10 was colocalized with Tau aggregates in the cell body of several neurons. Conclusions The present findings suggest that USP10 plays a key role in the initiation of pathogenic Tau aggregation in AD through SG formation.