2021/07/08 更新

写真a

イグチ ヨウヘイ
井口 洋平
IGUCHI Yohei
所属
医学部附属病院 脳神経内科 助教
大学院担当
大学院医学系研究科
職名
助教

学位 1

  1. 博士(医学) ( 2010年3月   名古屋大学 ) 

研究キーワード 5

  1. Neuroscience

  2. Neurodegeneration

  3. Chemistry

  4. Biology

  5. Amyotrophic Lateral Sclerosis

研究分野 1

  1. ライフサイエンス / 神経内科学

経歴 7

  1. 名古屋大学医学部附属病院   脳神経内科   助教

    2018年4月 - 現在

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    国名:日本国

  2. 名古屋大学医学部附属病院   神経内科   医員

    2016年8月 - 2018年3月

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    国名:日本国

  3. カナダ・ラバル大学   ポスドク研究員

    2013年6月 - 2016年6月

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    国名:日本国

  4. 名古屋大学大学院医学系研究科   神経内科   客員研究員

    2010年4月 - 2013年6月

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    国名:日本国

  5. 名古屋大学大学院医学系研究科   神経内科   大学院生(博士課程)

    2006年4月 - 2010年3月

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    国名:日本国

  6. 名古屋第一赤十字病院   神経内科   医員

    2003年4月 - 2006年3月

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    国名:日本国

  7. 名古屋第一赤十字病院   初期研修医

    2001年4月 - 2003年3月

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    国名:日本国

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学歴 1

  1. 名古屋大学   医学系研究科

    2006年4月 - 2010年3月

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    国名: 日本国

所属学協会 6

  1. 日本内科学会

  2. 日本神経科学会

  3. 日本神経学会

  4. 日本神経科学学会

  5. 日本神経学会

  6. 日本内科学会

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論文 13

  1. Pathway from TDP-43-Related Pathology to Neuronal Dysfunction in Amyotrophic Lateral Sclerosis and Frontotemporal Lobar Degeneration

    Riku Yuichi, Seilhean Danielle, Duyckaerts Charles, Boluda Susana, Iguchi Yohei, Ishigaki Shinsuke, Iwasaki Yasushi, Yoshida Mari, Sobue Gen, Katsuno Masahisa

    INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES   22 巻 ( 8 )   2021年4月

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    記述言語:日本語   出版者・発行元:International Journal of Molecular Sciences  

    Transactivation response DNA binding protein 43 kDa (TDP-43) is known to be a pathologic protein in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). TDP-43 is normally a nuclear protein, but affected neurons of ALS or FTLD patients exhibit mislocalization of nuclear TDP-43 and cytoplasmic inclusions. Basic studies have suggested gain-of-neurotoxicity of aggregated TDP-43 or loss-of-function of intrinsic, nuclear TDP-43. It has also been hypothesized that the aggregated TDP-43 functions as a propagation seed of TDP-43 pathology. However, a mechanistic discrepancy between the TDP-43 pathology and neuronal dysfunctions remains. This article aims to review the observations of TDP-43 pathology in autopsied ALS and FTLD patients and address pathways of neuronal dysfunction related to the neuropathological findings, focusing on impaired clearance of TDP-43 and synaptic alterations in TDP-43-related ALS and FTLD. The former may be relevant to intraneuronal aggregation of TDP-43 and exocytosis of propagation seeds, whereas the latter may be related to neuronal dysfunction induced by TDP-43 pathology. Successful strategies of disease-modifying therapy might arise from further investigation of these subcellular alterations.

    DOI: 10.3390/ijms22083843

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  2. The wide-ranging clinical and genetic features in Japanese families with valosin-containing protein proteinopathy

    Ando Takashi, Nakamura Ryoichi, Kuru Satoshi, Yokoi Daichi, Atsuta Naoki, Koike Haruki, Suzuki Masashi, Hara Kazuhiro, Iguchi Yohei, Harada Yumiko, Yoshida Yusuke, Hattori Makoto, Murakami Ayuka, Noda Seiya, Kimura Seigo, Sone Jun, Nakamura Tomohiko, Goto Yoji, Mano Kazuo, Okada Hisashi, Okuda Satoshi, Nishino Ichizo, Ogi Tomoo, Sobue Gen, Katsuno Masahisa

    NEUROBIOLOGY OF AGING   100 巻   頁: 120.e1 - 120.e6   2021年4月

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    記述言語:日本語   出版者・発行元:Neurobiology of Aging  

    Mutations in the valosin-containing protein (VCP) gene are known to cause various neurodegenerative disorders. Here, we report 8 Japanese patients [6 men, 2 women; median age at onset: 49.5 (range, 35–58) years] from 5 unrelated families with VCP missense mutations. Although 7 of 8 patients were diagnosed with either inclusion body myopathy or amyotrophic lateral sclerosis, 1 patient showed demyelinating polyneuropathy, which was confirmed by longitudinal nerve conduction studies. Sural nerve biopsy of the patient revealed intranuclear ubiquitin staining in Schwann cells. Three known pathogenic VCP mutations (p.Arg191Gln, p.Arg155Cys, and p.Ile126Phe) were detected. A novel mutation, c.293 A>T (p.Asp98Val), was also identified in a patient with amyotrophic lateral sclerosis and frontotemporal dementia. This mutation was predicted to be “deleterious” or “disease causing” using in silico mutation analyses. In conclusion, demyelinating polyneuropathy may be a novel phenotype caused by VCP mutations. The p.Asp98Val mutation was found to be a novel pathogenic mutation of VCP proteinopathy. We believe our cases represent a wide clinical spectrum of VCP mutations.

    DOI: 10.1016/j.neurobiolaging.2020.10.028

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  3. Aggresome formation and liquid-liquid phase separation independently induce cytoplasmic aggregation of TAR DNA-binding protein 43

    Watanabe Seiji, Inami Hidekazu, Oiwa Kotaro, Murata Yuri, Sakai Shohei, Komine Okiru, Sobue Akira, Iguchi Yohei, Katsuno Masahisa, Yamanaka Koji

    CELL DEATH & DISEASE   11 巻 ( 10 ) 頁: 909   2020年10月

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    記述言語:日本語   出版者・発行元:Cell Death and Disease  

    Cytoplasmic inclusion of TAR DNA-binding protein 43 (TDP-43) is a pathological hallmark of amyotrophic lateral sclerosis (ALS) and a subtype of frontotemporal lobar degeneration (FTLD). Recent studies have suggested that the formation of cytoplasmic TDP-43 aggregates is dependent on a liquid–liquid phase separation (LLPS) mechanism. However, it is unclear whether TDP-43 pathology is induced through a single intracellular mechanism such as LLPS. To identify intracellular mechanisms responsible for TDP-43 aggregation, we established a TDP-43 aggregation screening system using a cultured neuronal cell line stably expressing EGFP-fused TDP-43 and a mammalian expression library of the inherited ALS/FTLD causative genes, and performed a screening. We found that microtubule-related proteins (MRPs) and RNA-binding proteins (RBPs) co-aggregated with TDP-43. MRPs and RBPs sequestered TDP-43 into the cytoplasmic aggregates through distinct mechanisms, such as microtubules and LLPS, respectively. The MRPs-induced TDP-43 aggregates were co-localized with aggresomal markers and dependent on histone deacetylase 6 (HDAC6), suggesting that aggresome formation induced the co-aggregation. However, the MRPs-induced aggregates were not affected by 1,6-hexanediol, an LLPS inhibitor. On the other hand, the RBPs-induced TDP-43 aggregates were sensitive to 1,6-hexanediol, but not dependent on microtubules or HDAC6. In sporadic ALS patients, approximately half of skein-like TDP-43 inclusions were co-localized with HDAC6, but round and granular type inclusion were not. Moreover, HDAC6-positive and HDAC6-negative inclusions were found in the same ALS patient, suggesting that the two distinct pathways are both involved in TDP-43 pathology. Our findings suggest that at least two distinct pathways (i.e., aggresome formation and LLPS) are involved in inducing the TDP-43 pathologies.

    DOI: 10.1038/s41419-020-03116-2

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  4. Exploring the factors underlying remyelination arrest by studying the post-transcriptional regulatory mechanisms of cystatin F gene

    Li Jiayi, Durose Wilaiwan Wisessmith, Ito Junko, Kakita Akiyoshi, Iguchi Yohei, Katsuno Masahisa, Kunisawa Kazuo, Shimizu Takeshi, Ikenaka Kazuhiro

    JOURNAL OF NEUROCHEMISTRY     2020年10月

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    記述言語:日本語   出版者・発行元:Journal of Neurochemistry  

    Remyelination plays an important role in determining the fate of demyelinating disorders. However, it is arrested during chronic disease states. Cystatin F, a papain-like lysosomal cysteine proteinase inhibitor, is a crucial regulator of demyelination and remyelination. Using hemizygous proteolipid protein transgenic 4e (PLP4e/-) mice, an animal model of chronic demyelination, we found that cystatin F mRNA expression was induced at 2.5 months of age and up-regulated in the early phase of demyelination, but significantly decreased in the chronic phase. We next investigated cystatin F regulatory factors as potential mechanisms of remyelination arrest in chronic demyelinating disorders. We used the CysF-STOP-tetO::Iba-mtTA mouse model, in which cystatin F gene expression is driven by the tetracycline operator. Interestingly, we found that forced cystatin F mRNA over-expression was eventually decreased. Our findings show that cystatin F expression is modulated post-transcriptionally. We next identified embryonic lethal, abnormal vision, drosophila like RNA-binding protein 1 (ELAVL-1), and miR29a as cystatin F mRNA stabilizing and destabilizing factors, respectively. These roles were confirmed in vitro in NIH3T3 cells. Using postmortem plaque samples from human multiple sclerosis patients, we also confirmed that ELAVL-1 expression was highly correlated with the previously reported expression pattern of cystatin F. These data indicate the important roles of ELAVL-1 and miR29a in regulating cystatin F expression. Furthermore, they provide new insights into potential therapeutic targets for demyelinating disorders. (Figure presented.).

    DOI: 10.1111/jnc.15190

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  5. Therapeutic monoclonal antibody targeting of neuronal pentraxin receptor to control metastasis in gastric cancer

    Kanda Mitsuro, Shimizu Dai, Sawaki Koichi, Nakamura Shunsuke, Umeda Shinichi, Miwa Takashi, Tanaka Haruyoshi, Tanaka Chie, Hayashi Masamichi, Iguchi Yohei, Yamada Suguru, Katsuno Masahisa, Kodera Yasuhiro

    MOLECULAR CANCER   19 巻 ( 1 ) 頁: 131   2020年8月

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    記述言語:日本語   出版者・発行元:Molecular Cancer  

    Background: Controlling metastasis is essential for improving the prognosis of patients with gastric cancer (GC). Here, we aimed to identify a molecule required for GC metastasis and to investigate its potential utility as a target for the development of therapeutic antibodies (Abs). Methods: Transcriptome and bioinformatics analyses of human GC cell lines identified the neuronal pentraxin receptor (NPTXR) as a candidate molecule. NPTXR function was probed by modulating its expression in GC cells and assessing the effects on intracellular signaling and malignant behaviors in vitro and in mouse xenograft models. We also generated anti-NPTXR Abs and Nptxr -/- mice, and assessed the clinical significance of NPTXR expression in GC specimens. Results: NPTXR mRNA expression in clinical specimens was associated with disease progression and was significantly higher in tissues from GC patients with distant metastasis compared with those without. NPTXR regulated expression of genes involved in metastatic behaviors as well as activation of the PI3K-AKT-mTOR, FAK-JNK, and YAP signaling pathways. NPTXR silencing promoted caspase-mediated apoptosis and attenuated GC cell proliferation, cell cycle progression, migration, invasion, adhesion, stem cell-like properties, and resistance to 5-fluorouracil in vitro, and also inhibited the tumorigenicity of GC cells in vivo. Anti-NPTXR Abs inhibited GC peritoneal metastasis in mice. Nptxr -/- mice showed no abnormalities in reproduction, development, metabolism, or motor function. Conclusions: NPTXR plays an essential role in controlling the malignant behavior of GC cells in vitro and in vivo. NPTXR-targeting Abs may thus have utility as novel diagnostic tools and/or treatment modalities for GC.

    DOI: 10.1186/s12943-020-01251-0

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  6. NUS1 mutation in a family with epilepsy, cerebellar ataxia, and tremor

    Araki Kunihiko, Nakamura Ryoichi, Ito Daisuke, Kato Kohji, Iguchi Yohei, Sahashi Kentaro, Toyama Miho, Hamada Kensuke, Okamoto Nobuhiko, Wada Yoshinao, Nakamura Tomohiko, Ogi Tomoo, Katsuno Masahisa

    EPILEPSY RESEARCH   164 巻   頁: 106371   2020年8月

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    記述言語:日本語   出版者・発行元:Epilepsy Research  

    We report on familial 5 epilepsy patients with autosomal dominant inheritance of a novel heterozygous NUS1 frameshift mutation. All patients had cerebellar ataxia and tremor. Three patients were diagnosed with childhood absence epilepsy, 1 patient with generalized epilepsy, and 1 patient with parkinsonism without epilepsy. Our cases and previously reported cases with deletions of chromosome 6q22 that include NUS1 share these common symptoms. In a cellular experiment, NUS1 mutation led to a substantial reduction of the protein level of NUS1. NUS1 mutation could contribute to epilepsy pathogenesis and also constitute a distinct syndromic entity with cerebellar ataxia and tremor.

    DOI: 10.1016/j.eplepsyres.2020.106371

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  7. Characteristic Features of FUS Inclusions in Spinal Motor Neurons of Sporadic Amyotrophic Lateral Sclerosis 査読有り 国際誌

    Ikenaka Kensuke, Ishigaki Shinsuke, Iguchi Yohei, Kawai Kaori, Fujioka Yusuke, Yokoi Satoshi, Abdelhamid Rehab F., Nagano Seiichi, Mochizuki Hideki, Katsuno Masahisa, Sobue Gen

    JOURNAL OF NEUROPATHOLOGY AND EXPERIMENTAL NEUROLOGY   79 巻 ( 4 ) 頁: 370 - 377   2020年4月

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    記述言語:日本語   出版者・発行元:Journal of Neuropathology and Experimental Neurology  

    Alterations of RNA metabolism caused by mutations in RNA-binding protein genes, such as transactivating DNA-binding protein-43 (TDP-43) and fused in sarcoma (FUS), have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Unlike the accumulation of TDP43, which is accepted as a pathological hall mark of sporadic ALS (sALS), FUS pathology in sALS is still under debate. Although immunoreactive inclusions of FUS have been detected in sALS patients previously, the technical limitation of signal detection, including the necessity of specific antigen retrieval, restricts our understanding of FUS-associated ALS pathology. In this study, we applied a novel detection method using a conventional antigen retrieval technique with Sudan Black B treatment to identify FUS-positive inclusions in sALS patients. We classified pathological motor neurons into 5 different categories according to the different aggregation characteristics of FUS and TDP-43. Although the granular type was more dominant for inclusions with TDP-43, the skein-like type was more often observed in FUS-positive inclusions, suggesting that these 2 proteins undergo independent aggregation processes. Moreover, neurons harboring FUS-positive inclusions demonstrated substantially reduced expression levels of dynactin-1, a retrograde motor protein, indicating that perturbation of nucleocytoplasmic transport is associated with the formation of cytoplasmic inclusions of FUS in sALS.

    DOI: 10.1093/jnen/nlaa003

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  8. Elevated serum creatine kinase in the early stage of sporadic amyotrophic lateral sclerosis 査読有り

    Ito Daisuke, Hashizume Atsushi, Hijikata Yasuhiro, Yamada Shinichiro, Iguchi Yohei, Iida Madoka, Kishimoto Yoshiyuki, Moriyoshi Hideyuki, Hirakawa Akihiro, Katsuno Masahisa

    JOURNAL OF NEUROLOGY   266 巻 ( 12 ) 頁: 2952 - 2961   2019年12月

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    記述言語:日本語   出版者・発行元:Journal of Neurology  

    Objective: To assess the changes of muscle-related biomarkers at the early stage of amyotrophic lateral sclerosis, and to confirm these findings in an experimental animal model. Methods: Thirty-nine subjects with sporadic amyotrophic lateral sclerosis and 20 healthy controls were enrolled and longitudinally evaluated. We evaluated serum creatine kinase and creatinine levels and appendicular lean soft-tissue mass using dual X-ray absorptiometry. The levels of biomarkers at early ALS stages were estimated using linear mixed models with unstructured correlation and random intercepts. We also analyzed the longitudinal changes of serum creatine kinase and creatinine, together with the mRNA levels of acetylcholine receptor subunit γ (Chrng) and muscle-associated receptor tyrosine kinase, markers of denervation, in the gastrocnemius muscle of superoxide dismutase 1 (SOD1)G93A transgenic mice, an animal model of amyotrophic lateral sclerosis. Results: The estimated levels of creatine kinase were higher in subjects with amyotrophic lateral sclerosis at the early stage than in healthy controls, although the estimated appendicular lean soft-tissue mass and creatinine levels were equivalent between both groups, suggesting that the elevation of creatine kinase precedes both muscular atrophy and subjective motor symptoms in sporadic amyotrophic lateral sclerosis. In SOD1G93A mice, the serum levels of creatine kinase were elevated at 9 weeks of age (peri-onset) when Chrng started to be up-regulated, and were then down-regulated at 15 weeks of age, consistent with the clinical data from patients with sporadic amyotrophic lateral sclerosis. Interpretation: Creatine kinase elevation precedes muscular atrophy and reflects muscle denervation at the early stage.

    DOI: 10.1007/s00415-019-09507-6

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  9. TDP-43 regulates early-phase insulin secretion via CaV1.2-mediated exocytosis in islets 査読有り 国際誌

    Araki Kunihiko, Araki Amane, Honda Daiyu, Izumoto Takako, Hashizume Atsushi, Hijikata Vasuhiro, Yamada Shinichiro, Iguchi Yohei, Hara Akitoshi, Ikumi Kazuhiro, Kawai Kaori, Ishigaki Shinsuke, Nakamichi Yoko, Tsunekawa Shin, Seino Yusuke, Yamamoto Akiko, Takayama Yasunori, Hidaka Shihomi, Tominaga Makoto, Ohara-Imaizumi Mica, Suzuki Atsushi, Ishiguro Hiroshi, Enomoto Atsushi, Yoshida Mari, Arima Hiroshi, Muramatsu Shin-ichi, Sobue Gen, Katsuno Masahisa

    JOURNAL OF CLINICAL INVESTIGATION   129 巻 ( 9 ) 頁: 3578 - 3593   2019年9月

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    記述言語:日本語   出版者・発行元:Journal of Clinical Investigation  

    TAR DNA-binding protein 43 kDa (TDP-43), encoded by TARDBP, is an RNA-binding protein, the nuclear depletion of which is the histopathological hallmark of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder affecting both upper and lower motor neurons. Besides motor symptoms, patients with ALS often develop nonneuronal signs including glucose intolerance, but the underlying pathomechanism is still controversial, i.e., whether it is impaired insulin secretion and/or insulin resistance. Here, we showed that ALS subjects reduced early-phase insulin secretion and that the nuclear localization of TDP-43 was lost in the islets of autopsied ALS pancreas. Loss of TDP-43 inhibited exocytosis by downregulating CaV1.2 calcium channels, thereby reducing early-phase insulin secretion in a cultured β cell line (MIN6) and β cell-specific Tardbp-knockout mice. Overexpression of CaV1.2 restored early-phase insulin secretion in Tardbp-knocked-down MIN6 cells. Our findings suggest that TDP-43 regulates cellular exocytosis mediated by L-type voltage-dependent calcium channels and, thus, plays an important role in the early phase of insulin secretion by pancreatic islets. Thus, nuclear loss of TDP-43 is implicated in not only the selective loss of motor neurons, but also in glucose intolerance due to impaired insulin secretion at an early stage of ALS.

    DOI: 10.1172/JCI124481

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  10. Preclinical progression of neurodegenerative diseases

    Katsuno Masahisa, Sahashi Kentaro, Iguchi Yohei, Hashizume Atsushi

    NAGOYA JOURNAL OF MEDICAL SCIENCE   80 巻 ( 3 ) 頁: 289 - 298   2018年8月

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    記述言語:日本語  

    DOI: 10.18999/nagjms.80.3.289

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  11. Understanding of the role of proteinaceous inclusions in spinal and bulbar muscular atrophy

    Sahashi K., Kondo N., Iida M., Nakatsuji H., Tohnai G., Iguchi Y., Sobue G., Katsuno M.

    JOURNAL OF THE NEUROLOGICAL SCIENCES   381 巻   頁: 709 - 709   2017年10月

  12. The role of TDP-43 secretion in association with exosomes

    Iguchi Y., Eid L., Parent M., Riku Y., Kawai K., Yoshida M., Katsuno M., Sobue G., Julien J. P.

    JOURNAL OF THE NEUROLOGICAL SCIENCES   381 巻   頁: 208 - 209   2017年10月

  13. Altered Tau Isoform Ratio Caused by Loss of FUS and SFPQ Function Leads to FTLD-like Phenotypes 査読有り

    Ishigaki Shinsuke, Fujioka Yusuke, Okada Yohei, Riku Yuichi, Udagawa Tsuyoshi, Honda Daiyu, Yokoi Satoshi, Endo Kuniyuki, Ikenaka Kensuke, Takagi Shinnosuke, Iguchi Yohei, Sahara Naruhiko, Takashima Akihiko, Okano Hideyuki, Yoshida Mari, Warita Hitoshi, Aoki Masashi, Watanabe Hirohisa, Okado Haruo, Katsuno Masahisa, Sobue Gen

    CELL REPORTS   18 巻 ( 5 ) 頁: 1118 - 1131   2017年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Cell Reports  

    Fused in sarcoma (FUS) and splicing factor, proline- and glutamine-rich (SFPQ) are RNA binding proteins that regulate RNA metabolism. We found that alternative splicing of the Mapt gene at exon 10, which generates 4-repeat tau (4R-T) and 3-repeat tau (3R-T), is regulated by interactions between FUS and SFPQ in the nuclei of neurons. Hippocampus-specific FUS- or SFPQ-knockdown mice exhibit frontotemporal lobar degeneration (FTLD)-like behaviors, reduced adult neurogenesis, accumulation of phosphorylated tau, and hippocampal atrophy with neuronal loss through an increased 4R-T/3R-T ratio. Normalization of this increased ratio by 4R-T-specific silencing results in recovery of the normal phenotype. These findings suggest a biological link among FUS/SFPQ, tau isoform alteration, and phenotypic expression, which may function in the early pathomechanism of FTLD.

    DOI: 10.1016/j.celrep.2017.01.013

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講演・口頭発表等 2

  1. TDP-43代謝におけるエクソソームの役割 国際会議

    井口 洋平

    第59回日本神経学会学術大会  2018年 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

  2. Emerging roles of exosomes in TDP-43 proteinopathy 招待有り 国際会議

    井口 洋平

    The 60th Annual Meeting of JSN  2017年 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

科研費 5

  1. 孤発性ALSにおける凝集型TDP-43の生体内伝播メカニズムの解明

    研究課題/研究課題番号:20H03589  2020年4月 - 2023年3月

    井口 洋平

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    担当区分:研究代表者 

    配分額:17680000円 ( 直接経費:13600000円 、 間接経費:4080000円 )

    孤発性筋萎縮性側索硬化症において凝集型TDP-43がニューロン間をプリオンのように伝播することが想定されるが、実際に生体内でこのTDP-43のプリオン様伝播を証明した事例はない。研究代表者らはCre発現マウスとAAV-CMV-FLEXベクターを用いることによりTDP-43の生体内における細胞間伝播を強く示唆する結果を得ている。本研究では凝集型TDP-43の生体内伝播を”確実に”証明し、次にその伝播を修飾する因子を検討しsALSの病態抑止療法への展開を目指す。

  2. 超早期ライフステージに着目した神経変性疾患の時空間特異性の解明

    研究課題/研究課題番号:20H00527  2020年4月 - 2023年3月

    勝野 雅央

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    担当区分:研究分担者 

    神経変性疾患に共通する病態的特徴は、特定のニューロンが選択的に変性すること(空間的特異性)および中高年以降に遅発性に発症・進行すること(時間的特異性)である。本研究では、運動ニューロン疾患を研究対象とし、マウスモデルや患者由来iPSCを用い、マルチオミクスやDREADD、脳Caイメージングなどを駆使して超早期ライフステージにおけるニューロン変性分子病態とその年齢依存性変化を解明することで、神経変性における分子病態の真の起点を明らかにする。さらに、ニューロン分化と変性の関連を解析することで、選択的ニューロン死の本質的原因を究明する。

  3. 発達期遺伝子制御の異常に基づいた運動ニューロン変性機序の解明

    研究課題/研究課題番号:19H03545  2019年4月 - 2022年3月

    佐橋 健太郎

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    担当区分:研究分担者 

    脊髄性筋萎縮症(SMA)はSMN蛋白欠乏により運動ニューロン死をきたす乳児死亡最多の遺伝子疾患である。SMNは発達期需要度が高く、RNAの代謝や輸送を担うため、SMAでは発達期RNA病態が示唆されるが神経変性機構は解明されていない。ノンコーディングRNA(ncRNA)は神経発生や分化に関わり、そのRNA発現調節が注目されている。そこでSMA病態に関し、ncRNAを介するRNAネットワーク異常を起因とする、胎生遺伝子の制御異常による発症機構の検討が重要であると考え、本研究ではマウス胎仔、ヒトiPS細胞を用いてその機序を明らかにし、バイオマーカーと治療法開発につなげていく。

  4. 神経特異的polysome解析によるALS/FTLD病態解明と分子標的療法の開発

    研究課題/研究課題番号:17K09753  2017年4月 - 2020年3月

    井口 洋平

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    担当区分:研究代表者 

    配分額:4550000円 ( 直接経費:3500000円 、 間接経費:1050000円 )

    ALSとFTLDは神経細胞が選択的に変性する原因不明の神経変性疾患である。TDP-43やTBK1はALS/FTLDの神経細胞において、その機能喪失が神経細胞死に関連していると考えられている分子であるがその変性メカニズムはよくわかっていない。研究代表者らは新たに神経細胞特異的synapsinプロモーター下にGFPという特別に標識したリボソーム蛋白“GFP-RPL10a(GRP)”とCreを共発現するSyn-GRP-Creマウスを作成し、このマウスを用いてTDP-43やTBK1の機能喪失が生体内神経細胞の変性をおこす病態を神経細胞特異的な網羅的遺伝子解析により解析した。
    ALSとFTLDは上位・下位運動ニューロンや前頭側頭葉皮質のニューロンが選択的に変性する原因不明の神経変性疾患である。これらの疾患における神経変性病態を解明するにはニューロン特異的な解析が必須であるが、モデル動物において変性過程にあるニューロンの単離は非常に困難である。この問題を解決するために、Syn-Ribotag-Creマウスを作成した。このマウスと各floxマウスを交配することで特定の遺伝子をノックアウトしたニューロン特異的な遺伝子発現解析が可能となった。今後多くの神経変性疾患の病態解明に利用することができるため研究を発展させていきたい。

  5. 運動ニューロン疾患における神経コミュニケーション異常の分子病態解明と治療法開発

    研究課題/研究課題番号:17H04195  2017年4月 - 2020年3月

    勝野 雅央

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    担当区分:研究分担者 

    運動ニューロン疾患は筋力低下や筋萎縮などの症状が進行する神経変性疾患であり、成人では筋萎縮性側索硬化症(ALS)と球脊髄性筋萎縮症(SBMA)とがそのほとんどを占める。本研究では、ALSの病因分子であるTDP-43が膵beta細胞においてインスリン分泌を調整する作用を有することを明らかにした。SBMAについては、原因蛋白質である変異アンドロゲン受容体がDNAメチル化酵素の発現を増加させることおよびSrcのリン酸化を亢進することを明らかにした。
    本研究は、ニューロンが細胞外分泌などを介して行っている他の細胞との情報・分子伝達の異常が運動ニューロン疾患における神経・筋システム変性の基盤であるとの仮説に基づき、従来にはない画期的な視点で運動ニューロン疾患の病態の本質を明らかにした。この成果は運動ニューロン疾患の進行メカニズムの解明と、それに基づく予後予測や治療法の開発に直結するだけでなく、認知症を含む他の多くの神経変性疾患や筋疾患などの病態メカニズム研究に応用が可能である。