若手道場口演（Wakate Dojo）

Wakate Dojo Disorders of Nervous System 4 若手道場口演神経系の疾患4

7月26日（金）10:10～10:30　第10会場（万代島ビル　6F　会議室） 2WD10cm2-1 自閉スペクトラム症関連遺伝子POGZの患者特異的de novo変異の大脳皮質神経分化における表現型解析 Kensuke Matsumura（松村憲佑）^1,2，Kaoru Seiriki（勢力薫）^1,2，Masashi Nagase（永瀬将志）³，Shinya Ayabe（綾部信哉）⁴，Ikuko Yamada（山田郁子）⁵，Tamio Furuse（古瀬民生）⁵，Kana Yamamoto（山本果奈）¹，Kohei Kitagawa（北川航平）¹，Tokuichi Iguchi（猪口徳一）⁶，Makoto Sato（佐藤真）^6,7,8，Shun Yamaguchi（山口瞬）^9,10，Masaru Tamura（田村勝）⁵，Shigeharu Wakana（若菜茂晴）^5,11，Atsushi Yoshiki（吉木淳）⁴，Ayako M. Watabe（渡部文子）^3,12，Hideyuki Okano（岡野栄之）¹³，Kazuhiro Takuma（田熊一敞）^14,15，Ryota Hashimoto（橋本亮太）^16,17，Hitoshi Hashimoto（橋本均）^1,15,18,19，Takanobu Nakazawa（中澤敬信）^1,14 ¹大阪大院薬神経薬理 ²大阪大・博士課程教育リーディングプログラム・生体統御ネットワーク医学教育プログラム ³東京慈恵医大総合医科学研セ臨床医学研究所 ⁴理研BRC実験動物開発室 ⁵理研BRCマウス表現型解析開発チーム ⁶大阪大院医神経機能形態学 ⁷大阪大・金沢大・浜松医科大・千葉大・福井大連合小児発達学研究科 ⁸福井大・子どものこころの発達研究センター ⁹岐阜大院医神経統御・高次神経形態 ¹⁰岐阜大・生命の鎖統合研究センター ¹¹神戸医療産業都市推進機構・先端医療研究センター・老化機構研究 ¹²慈恵医大・痛み脳科学センター ¹³慶應大医生理 ¹⁴大阪大院歯薬理 ¹⁵大阪大・金沢大・浜松医科大・千葉大・福井大連合小児発達学研究科附属子どものこころの分子統御機構研究センター ¹⁶国立精神・神経医療研究センター・精神保健研究所・精神疾患病態研究部 ¹⁷大阪大 ¹⁸大阪大データビリティフロンティア機構 ¹⁹大阪大先導的学際研究・超次元ライフイメージング研究部門 Autism spectrum disorder (ASD) is one of neurodevelopmental disorders (NDDs) characterized by reduced verbal communication abilities and social interactions, stereotyped repetitive behaviors and restricted interests. Although genetic studies have identified numerous candidate genetic variants, the molecular etiology of ASD remains poorly understood. In addition to common genetic variants, de novo mutations, genomic spontaneous mutations identified in an affected child, but not unaffected parents, contribute to the risk of ASD. In particular, genes with highly recurrent de novo possible loss-of-function mutations, which have been identified in multiple unrelated patients, are likely to play key roles in the etiology of ASD. Recently, we and other groups have identified that POGZ is one of the most recurrently mutated genes (at least 45 independent de novo possible loss-of-function mutations) in patients with NDDs, including ASD, among the high-confidence ASD risk genes, suggesting that de novo POGZ mutations can be related to ASD pathogenesis. However, the biological significance of these ASD-associated de novo POGZ mutations and the role of POGZ itself in the brain remain unknown. Here, we present the role of POGZ in neuronal differentiation and functional characterization of de novo POGZ mutations. We observed that Pogz was highly expressed in the developing mouse cerebral cortex during embryonic neurogenesis. We also determined that Pogz knockdown impaired neuronal differentiation, which was rescued by overexpression of wild-type POGZ and de novo POGZ mutants identified in unaffected controls but not by overexpression of ASD-related de novo POGZ mutants. Furthermore, the neuronal differentiation was impaired in neural stem cells derived from an ASD patient carrying a de novo POGZ mutation. We also determined that the de novo POGZ mutation identified in the ASD patient resulted in impaired cortical neuronal development and ASD-like phenotypes, including autistic abnormal behaviors, in mice. Our results suggest that ASD-associated de novo POGZ mutants with disrupted function in neuronal differentiation show an effect likely to result in ASD-like features. These findings provide important insights into the cellular basis of ASD.		7月26日（金）9:30～9:50　第10会場（万代島ビル　6F　会議室） 2WD10cm2-2 MARK4のアルツハイマー病リスク関連変異は、機能獲得型（gain-of-function）によりタウの蓄積を増加させ神経変性を増悪する Toshiya Oba（大場俊弥）¹，Taro Saito（斎藤太郎）¹，Akiko Asada（淺田明子）¹，Koichi Iijima（飯島浩一）^2,3，Kanae Ando（安藤香奈絵）¹ ¹首都大学東京理学部生命科学科 ²国立長寿医療センター ³名古屋市立大学薬学部大学院薬学研究科 Alzheimer's disease (AD) is a primary cause of age-dependent dementia. Accumulation of abnormal tau proteins is thought to cause neuron loss in AD. Tau is abnormally phosphorylated at many sites in disease brains, and among them, phosphorylation at Ser262 and Ser356 stabilizes tau and triggers the accumulation of hyperphosphorylated tau. Microtubule affinity-regulating kinase 4 (MARK4) is a major kinase that phosphorylates tau at Ser262/356. Recently, a mutation in MARK4, MARK4ΔGly316Glu317InsAsp, has been linked to the elevated risk of AD. It is not fully understood yet how this mutation in MARK4 increases AD risks. Here we report that the ΔGly316Glu317InsAsp mutation in MARK4 confers enhancement of its effects on tau accumulation and tau-induced neurodegeneration. We established transgenic fly lines that express human wild-type MARK4 (MARK4WT) or mutant MARK4 (MARK4ΔGly316Glu317InsAsp) and compared their effects on tau accumulation and toxicity in a fly model of tauopathy. Co-expression of MARK4WT increased tau phosphorylation at Ser262 and total tau levels. As previously suggested, MARK4WT failed to increase the levels of tau carrying unphosphorylatable alanine substitutions at Ser262 and Ser356 (S2A), suggesting that tau phosphorylation at these sites is required for MARK4WT to increase total tau levels. Interestingly, co-expression of MARK4ΔGly316Glu317InsAsp increased tau phosphorylation at Ser262 and total tau levels, and these effects were much more prominent compared to those with MARK4WT. Moreover, in contrast to MARK4WT, co-expression of MARK4ΔGly316Glu317InsAsp increased the levels of S2A tau, suggesting that MARK4ΔGly316Glu317InsAsp promotes tau accumulation via an additional mechanism. Finally, we found that co-expression of both MARK4WT and MARK4ΔGly316Glu317InsAsp exacerbated tau-mediated neurodegeneration, and the effects were much more prominent in flies co-expressing MARK4ΔGly316Glu317InsAsp. These results suggest that MARK4ΔGly316Glu317InsAsp promotes tau accumulation and toxicity via as-yet-unknown gain of function mechanisms, which may underlie the increased risk for AD.

7月26日（金）9:50～10:10　第10会場（万代島ビル　6F　会議室） 2WD10cm2-3 双極性障害患者で同定されたデノボ変異再現遺伝子改変マウスの解析 Takumi Nakamura（中村匠）^1,2，Kazuo Nakajima（中島一夫）²，Takaoki Kasahara（笠原和起）²，Yuki Kobayashi（小林祐樹）³，Itohara Shigeyoshi（糸原重美）³，Takashi Tsuboi（坪井貴司）¹，Tadafumi Kato（加藤忠史）² ¹東京大院総合文化研生命環境科学 ²理研CBS 精神疾患動態研究チーム ³理研CBS 行動遺伝学研究チーム Bipolar disorder is one of the common neuropsychiatric disorders with around 1% life time prevalence. Genetic factors are reported to be important for the development of bipolar disorder. However, the pathogenesis of bipolar disorder is still unclear. Recently, a trio-based exome sequencing study for bipolar disorder reported possible relationship between de novo mutations and bipolar disorder. In this study, we focused on likely gene disrupting (LGD), de novo mutations found in MACF1, EHD1 and KMT2C. In order to study the effect of the mutations in vivo, we generated mutant mice of Macf1, Ehd1 and Kmt2c using CRISPR/Cas9 system, which model the de novo mutations. To screen their behavioral abnormalities, we performed the IntelliCage analysis and wheel running activity test. Macf1 mutant mice significantly sticked to rewards in the IntelliCage analysis. This result was similarly observed in serotonin neuron activated mice. The Macf1 mutant mice also showed significantly less attention. In the wheel running activity test, we preliminarily found that the mutant mice of Macf1 and Ehd1 tended to show irregular patterns in the light-phase. With regard to KMT2C, the Kmt2c mutant mice showed several autistic-like traits, such as brain overgrowth and impairment in serial reversal learning task, although we expected that Kmt2c mutant mice would show bipolar disorder-like behavior. LGD, de novo mutations of KMT2C are actually reported in patients with autism. Thus, we reanalyzed the mutation found in the bipolar disorder patient and found that the de novo mutation was a somatic mosaic mutation. We assume that the mosaicism made the effect of LGD mutation of KMT2C milder. This study suggests that the LGD, de novo mutations found in bipolar disorder patients have the pathophysiological significance.