若手道場口演（Wakate Dojo）

Wakate Dojo Neural Excitability, Synapse and Glia 1 若手道場口演神経興奮性・シナプス・グリア1

7月25日（木）9:00～9:20　第10会場（万代島ビル　6F　会議室） 1WD10am1-1 G3BP1 inhibits the ubiquitinated protein aggregations induced by p62 and USP10 Sergei Alexander Anisimov（Anisimov Sergei Alexander）¹，Masahiko Takahashi（Takahashi Masahiko）¹，Yoshinori Katsuragi（Katsuragi Yoshinori）¹，Taichi Kakihana（Kakihana Taichi）¹，Hiroki Kitaura（Kitaura Hiroki）²，Akiyoshi Kakita（Kakita Akiyoshi）²，Masahiro Fujii（Fujii Masahiro）¹ ¹Niigata University Graduate School of Medical and Dental Sciences ²Niigata University, Brain Research Institute Background α-synuclein is a causative factor of Parkinson disease. The cystic fibrosis transmembrane conductance regulator ΔF508 (CFTR-ΔF508) is a causative factor of familial cystic fibrosis. Aberrant protein aggregations of α-synuclein and CFTR-ΔF508 in cells play a critical role in the pathogenesis of Parkinson disease and cystic fibrosis, respectively. We previously showed that ubiquitin-specific protease 10 (USP10) and p62 promote ubiquitinated protein aggregation and aggresome formation, and they stimulate aggregations of α-synuclein and CFTR-ΔF508. Ras GTPase-activating protein-binding protein 1 (G3BP1) is an interaction partner of USP10. We examined whether G3BP1 regulates protein aggregations of α-synuclein and CFTR-ΔF508. Results To examine the activity of G3BP1 in ubiquitinated protein aggregation, we reduced expression of G3BP1 in HeLa and 293T cells by G3BP1-siRNA, and the amount of ubiquitinated proteins before and after a proteasome inhibitor treatment (MG-132) was measured. G3BP1-KD augmented protein aggregation and HDAC6-positive aggresome formation of α-synuclein and CFTR-ΔF508, and the augmentations were reduced by USP10-KD or p62-KD, suggesting that G3BP1 inhibits USP10/p62-induced protein aggregation of CFTR-ΔF508 and α-synuclein. Immunoprecipitation study showed that G3BP1 interacted both with p62 and USP10, suggesting that interaction of G3BP1 with USP10 and/or p62 mediates the protein aggregation inhibition. A proteasome reporter assay suggested that G3BP1-KD inhibits proteasome activity to increase protein aggregations in HeLa cells. Western blot analysis showed that brain tissues derived from both normal individuals and PD patients expresses a low amount of G3BP1, and the amount in brain is much less that of p62 and USP10. These results suggest that an inhibitory activity of G3BP1 to p62/USP10-induced protein aggregation in brain is low before PD development. Conclusions Our findings suggest that G3BP1 is a negative regulator of protein aggregation, including α-synuclein, and a low expression of G3BP1 in the brain might be a factor promoting protein aggregation in neurodegenerative disorders, including PD.		7月25日（木）9:20～9:40　第10会場（万代島ビル　6F　会議室） 1WD10am1-2 パーキンソン病モデルマウスにおいて FABP3は α-シヌクレインの凝集を悪化させる Kazuya Matsuo（松尾和哉），An Cheng（程岸），Yasuharu Shinoda（篠田康晴），Kohji Fukunaga（福永浩司）東北大学大学院薬学研究科薬理学分野 [Background] Aggregation and oligomerization of α-synuclein (α-Syn) are promoted by polyunsaturated fatty acids (PUFAs) such as arachidonic acid (AA) so that PUFAs are likely involved in pathogenesis of Parkinson´s disease (PD). Heart-type fatty acid-binding protein (FABP3) is crucial for AA transport and metabolism in the brain. We previously reported that FABP3 is abundant in dopaminergic (DA) neurons in the mouse substantia nigra pars compacta (SNpc) (Shioda et al, J Neurocsci, 2010), where α-Syn aggregation and neuronal loss are typically observed in PD. However, it remains unclear whether and how FABP3 mediates DA neurodegeneration in PD. [Methods] To investigate the role of FABP3 in α-Syn pathology, FABP3 was overexpressed in PC12 cells in the presence of AA and α-Syn oligomerization was assessed. Further investigation was conducted using 1-methyl-1,2,3,6-tetrahydropiridine (MPTP)-treated PD model mice. [Results] The α-syn oligomerization and following cell death by AA treatment were aggravated in FABP3-overexpressing PC12 cells. These effects of FABP3 were diminished by a mutant FABP3 overexpression, which is unable to bind fatty acids. MPTP treatment induced α-syn accumulation in DA cell bodies in the mice SNpc, a part of which was also FABP3-positive. In contrast, DA neurodegeneration and motor deficits in addition to α-syn pathology were significantly suppressed in MPTP-treated FABP3 knockout mice. [Conclusion] We demonstrated that FABP3 is involved in AA and MPTP-induced α-syn oligomerization and aggregation in DA neurons. We further focus on FABP3 as a therapeutic target for synucleinopathies and develop FABP ligands.

7月25日（木）9:40～10:00　第10会場（万代島ビル　6F　会議室） 1WD10am1-3 ピルビン酸エチルはパーキンソン病モデルマウスのミトコンドリアストレスを軽減する Hidaka Haga（芳賀飛高），Yasushi Yabuki（矢吹悌），Kohji Fukunaga（福永浩司）東北大院薬薬理学 [Background] Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor dysfunction. About 30 % of PD patients also exhibit cognitive dysfunction, which is no appropriate therapy. We have developed novel therapy to rescue the mitochondria using methyl pyruvate. We also examine the effects of sigma-1 receptor agonist which was previously reported to rescue the mitochondria in heart failure (Biochem Biophys Acta 2014;1840:3320). [Methods] Animals were treated with MPTP (25 mg/kg, i.p.) for consecutive 5 days. One day after the final injection of MPTP, mice were treated once a day with ethyl pyruvate (EP) (25, 50, 100 mg/kg, i.p.) or sigma-1 receptor agonist, SA4503 (1 mg/kg, i.p.) for consecutive 4 weeks. Mice were then examined the motor and cognitive functions. [Results] Chronic administration of EP (100 mg/kg i.p.) or SA4503 (1 mg/kg, i.p.) improved not only motor deficits but also cognitive dysfunctions seen in PD model mice. When levels of tissue ATP and tyrosine hydroxylase (TH) protein were measured in SNpc-VTA, striatum and hippocampal CA1 region, the decreases in both ATP and TH levels of all regions in PD model mice were restored by administration of EP (100 mg/kg i.p.) or SA4503 (1 mg/kg, i.p.). Interestingly, the elevated oxidative damages such as 4-HNE- and nitrotyrosine-reactive protein levels in MPTP-treated mice were ameliorated by administration of EP (100 mg/kg i.p.) or SA4503 in SNpc-VTA, striatum, and hippocampal CA1 regions. [Discussion and conclusion] EP and SA4503 administration rescue the mitochondrial damages in in PD model mice, thereby improving both motor and cognitive dysfunction. The enhancement of mitochondrial ATP production and suppression of oxidative stress are possible mechanisms underlying neuroprotection of dopaminergic neurons.