研究者詳細 - 小野寺　理

論文 - 小野寺　理

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Inherited C-terminal TREX1 variants disrupt homology-directed repair to cause senescence and DNA damage phenotypes in Drosophila, mice, and humans

Samuel D. Chauvin, Shoichiro Ando, Joe A. Holley, Atsushi Sugie, Fang R. Zhao, Subhajit Poddar, Rei Kato, Cathrine A. Miner, Yohei Nitta, Siddharth R. Krishnamurthy, Rie Saito, Yue Ning, Yuya Hatano, Sho Kitahara, Shin Koide, W. Alexander Stinson, Jiayuan Fu, Nehalee Surve, Lindsay Kumble, Wei Qian, Oleksiy Polishchuk, Prabhakar S. Andhey, Cindy Chiang, Guanqun Liu, Ludovic Colombeau, Raphaël Rodriguez, Nicolas Manel, Akiyoshi Kakita, Maxim N. Artyomov, David C. Schultz, P. Toby Coates, Elisha D. O. Roberson, Yasmine Belkaid, Roger A. Greenberg, Sara Cherry, Michaela U. Gack, Tristan Hardy, Osamu Onodera, Taisuke Kato, Jonathan J. Miner

Nature Communications 15 ( 1 ) 2024年6月

掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

Abstract

Age-related microangiopathy, also known as small vessel disease (SVD), causes damage to the brain, retina, liver, and kidney. Based on the DNA damage theory of aging, we reasoned that genomic instability may underlie an SVD caused by dominant C-terminal variants in TREX1, the most abundant 3′−5′ DNA exonuclease in mammals. C-terminal TREX1 variants cause an adult-onset SVD known as retinal vasculopathy with cerebral leukoencephalopathy (RVCL or RVCL-S). In RVCL, an aberrant, C-terminally truncated TREX1 mislocalizes to the nucleus due to deletion of its ER-anchoring domain. Since RVCL pathology mimics that of radiation injury, we reasoned that nuclear TREX1 would cause DNA damage. Here, we show that RVCL-associated TREX1 variants trigger DNA damage in humans, mice, and Drosophila, and that cells expressing RVCL mutant TREX1 are more vulnerable to DNA damage induced by chemotherapy and cytokines that up-regulate TREX1, leading to depletion of TREX1-high cells in RVCL mice. RVCL-associated TREX1 mutants inhibit homology-directed repair (HDR), causing DNA deletions and vulnerablility to PARP inhibitors. In women with RVCL, we observe early-onset breast cancer, similar to patients with BRCA1/2 variants. Our results provide a mechanistic basis linking aberrant TREX1 activity to the DNA damage theory of aging, premature senescence, and microvascular disease.

DOI： 10.1038/s41467-024-49066-7

その他リンク： https://www.nature.com/articles/s41467-024-49066-7

TDP-43 differentially propagates to induce antero- and retrograde degeneration in the corticospinal circuits in mouse focal ALS models. 国際誌

Shintaro Tsuboguchi, Yuka Nakamura, Tomohiko Ishihara, Taisuke Kato, Tokiharu Sato, Akihide Koyama, Hideki Mori, Yuka Koike, Osamu Onodera, Masaki Ueno

Acta neuropathologica 2023年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by TDP-43 inclusions in the cortical and spinal motor neurons. It remains unknown whether and how pathogenic TDP-43 spreads across neural connections to progress degenerative processes in the cortico-spinal motor circuitry. Here we established novel mouse ALS models that initially induced mutant TDP-43 inclusions in specific neuronal or cell types in the motor circuits, and investigated whether TDP-43 and relevant pathological processes spread across neuronal or cellular connections. We first developed ALS models that primarily induced TDP-43 inclusions in the corticospinal neurons, spinal motor neurons, or forelimb skeletal muscle, by using adeno-associated virus (AAV) expressing mutant TDP-43. We found that TDP-43 induced in the corticospinal neurons was transported along the axons anterogradely and transferred to the oligodendrocytes along the corticospinal tract (CST), coinciding with mild axon degeneration. In contrast, TDP-43 introduced in the spinal motor neurons did not spread retrogradely to the cortical or spinal neurons; however, it induced an extreme loss of spinal motor neurons and subsequent degeneration of neighboring spinal neurons, suggesting a degenerative propagation in a retrograde manner in the spinal cord. The intraspinal degeneration further led to severe muscle atrophy. Finally, TDP-43 induced in the skeletal muscle did not propagate pathological events to spinal neurons retrogradely. Our data revealed that mutant TDP-43 spread across neuro-glial connections anterogradely in the corticospinal pathway, whereas it exhibited different retrograde degenerative properties in the spinal circuits. This suggests that pathogenic TDP-43 may induce distinct antero- and retrograde mechanisms of degeneration in the motor system in ALS.

DOI： 10.1007/s00401-023-02615-8

Phosphorylation of α-synuclein at T64 results in distinct oligomers and exerts toxicity in models of Parkinson's disease. 国際誌

Hideaki Matsui, Shinji Ito, Hideki Matsui, Junko Ito, Ramil Gabdulkhaev, Mika Hirose, Tomoyuki Yamanaka, Akihide Koyama, Taisuke Kato, Maiko Tanaka, Norihito Uemura, Noriko Matsui, Sachiko Hirokawa, Maki Yoshihama, Aki Shimozawa, Shin-Ichiro Kubo, Kenji Iwasaki, Masato Hasegawa, Ryosuke Takahashi, Keisuke Hirai, Akiyoshi Kakita, Osamu Onodera

Proceedings of the National Academy of Sciences of the United States of America 120 ( 23 ) e2214652120 2023年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

α-Synuclein accumulates in Lewy bodies, and this accumulation is a pathological hallmark of Parkinson's disease (PD). Previous studies have indicated a causal role of α-synuclein in the pathogenesis of PD. However, the molecular and cellular mechanisms of α-synuclein toxicity remain elusive. Here, we describe a novel phosphorylation site of α-synuclein at T64 and the detailed characteristics of this post-translational modification. T64 phosphorylation was enhanced in both PD models and human PD brains. T64D phosphomimetic mutation led to distinct oligomer formation, and the structure of the oligomer was similar to that of α-synuclein oligomer with A53T mutation. Such phosphomimetic mutation induced mitochondrial dysfunction, lysosomal disorder, and cell death in cells and neurodegeneration in vivo, indicating a pathogenic role of α-synuclein phosphorylation at T64 in PD.

DOI： 10.1073/pnas.2214652120

Candesartan prevents arteriopathy progression in cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy model. 査読国際誌

Taisuke Kato, Ri-Ichiroh Manabe, Hironaka Igarashi, Fuyuki Kametani, Sachiko Hirokawa, Yumi Sekine, Natsumi Fujita, Satoshi Saito, Yusuke Kawashima, Yuya Hatano, Shoichiro Ando, Hiroaki Nozaki, Akihiro Sugai, Masahiro Uemura, Masaki Fukunaga, Toshiya Sato, Akihide Koyama, Rie Saito, Atsushi Sugie, Yasuko Toyoshima, Hirotoshi Kawata, Shigeo Murayama, Masaki Matsumoto, Akiyoshi Kakita, Masato Hasegawa, Masafumi Ihara, Masato Kanazawa, Masatoyo Nishizawa, Shoji Tsuji, Osamu Onodera

The Journal of clinical investigation 131 ( 22 ) 2021年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

Cerebral small vessel disease (CSVD) causes dementia and gait disturbance due to arteriopathy. Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a hereditary form of CSVD caused by loss of high-temperature requirement A1 (HTRA1) serine protease activity. In CARASIL, arteriopathy causes intimal thickening, smooth muscle cell (SMC) degeneration, elastic lamina splitting, and vasodilation. The molecular mechanisms were proposed to involve the accumulation of matrisome proteins as substrates or abnormalities in transforming growth factor β (TGF-β) signaling. Here, we show that HTRA1-/- mice exhibited features of CARASIL-associated arteriopathy: intimal thickening, abnormal elastic lamina, and vasodilation. In addition, the mice exhibited reduced distensibility of the cerebral arteries and blood flow in the cerebral cortex. In the thickened intima, matrisome proteins, including the hub protein fibronectin (FN) and latent TGF-β binding protein 4 (LTBP-4), which are substrates of HTRA1, accumulated. Candesartan treatment alleviated matrisome protein accumulation and normalized the vascular distensibility and cerebral blood flow. Furthermore, candesartan reduced the mRNA expression of Fn1, Ltbp-4, and Adamtsl2, which are involved in forming the extracellular matrix network. Our results indicate that these accumulated matrisome proteins may be potential therapeutic targets for arteriopathy in CARASIL.

DOI： 10.1172/JCI140555

Age-related demethylation of the TDP-43 autoregulatory region in the human motor cortex. 国際誌

Yuka Koike, Akihiro Sugai, Norikazu Hara, Junko Ito, Akio Yokoseki, Tomohiko Ishihara, Takuma Yamagishi, Shintaro Tsuboguchi, Mari Tada, Takeshi Ikeuchi, Akiyoshi Kakita, Osamu Onodera

Communications biology 4 ( 1 ) 1107 - 1107 2021年9月

記述言語：英語掲載種別：研究論文（学術雑誌）

In amyotrophic lateral sclerosis (ALS), TAR DNA-binding protein 43 (TDP-43), which is encoded by TARDBP, forms aggregates in the motor cortex. This aggregate formation may be triggered by an increase in the TDP-43 level with aging. However, the amount of TDP-43 is autoregulated by alternative splicing of the TARDBP 3'UTR, and how this autoregulation is affected by aging remains to be elucidated. We found that DNA demethylation in the autoregulatory region in the TARDBP 3'UTR reduced alternative splicing and increased TARDBP mRNA expression. Furthermore, in the human motor cortex, we found that this region was demethylated with aging, resulting in increased expression of TARDBP mRNA. The acceleration of DNA demethylation in the motor cortex was associated with the age of ALS onset. In summary, the dysregulation of TDP-43 autoregulation by age-related DNA demethylation in the motor cortex may explain the contribution of aging and motor system selectivity in ALS.

DOI： 10.1038/s42003-021-02621-0

TDP-43 transports ribosomal protein mRNA to regulate axonal local translation in neuronal axons. 査読国際誌

Seiichi Nagano, Junki Jinno, Rehab F Abdelhamid, Yinshi Jin, Megumi Shibata, Shohei Watanabe, Sachiko Hirokawa, Masatoyo Nishizawa, Kenji Sakimura, Osamu Onodera, Hironori Okada, Takashi Okada, Yuko Saito, Junko Takahashi-Fujigasaki, Shigeo Murayama, Shuji Wakatsuki, Hideki Mochizuki, Toshiyuki Araki

Acta neuropathologica 140 ( 5 ) 695 - 713 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

Mislocalization and abnormal deposition of TDP-43 into the cytoplasm (TDP-43 proteinopathy) is a hallmark in neurons of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). However, the pathogenic mechanism of the diseases linked to TDP-43 is largely unknown. We hypothesized that the failure of mRNA transport to neuronal axons by TDP-43 may contribute to neurodegeneration in ALS and FTLD, and sought to examine the function of TDP-43 by identifying its target mRNA for axonal transport. We found that mRNAs related to translational function including ribosomal proteins (RPs) were decreased by shRNA-based TDP-43 knock-down in neurites of cortical neurons. TDP-43 binds to and transports the RP mRNAs through their 5' untranslated region, which contains a common 5' terminal oligopyrimidine tract motif and a downstream GC-rich region. We showed by employing in vitro and in vivo models that the RP mRNAs were translated and incorporated into native ribosomes locally in axons to maintain functionality of axonal ribosomes, which is required for local protein synthesis in response to stimulation and stress to axons. We also found that RP mRNAs were reduced in the pyramidal tract of sporadic ALS cases harboring TDP-43 pathology. Our results elucidated a novel function of TDP-43 to control transport of RP mRNAs and local translation by ribosomes to maintain morphological integrity of neuronal axons, and proved the influence of this function of TDP-43 on neurodegeneration in ALS and FTLD associated with TDP-43 proteinopathy.

DOI： 10.1007/s00401-020-02205-y

その他リンク： http://link.springer.com/article/10.1007/s00401-020-02205-y/fulltext.html

Toward allele-specific targeting therapy and pharmacodynamic marker for spinocerebellar ataxia type 3. 査読国際誌

Mercedes Prudencio, Hector Garcia-Moreno, Karen R Jansen-West, Rana Hanna Al-Shaikh, Tania F Gendron, Michael G Heckman, Matthew R Spiegel, Yari Carlomagno, Lillian M Daughrity, Yuping Song, Judith A Dunmore, Natalie Byron, Björn Oskarsson, Katharine A Nicholson, Nathan P Staff, Sorina Gorcenco, Andreas Puschmann, João Lemos, Cristina Januário, Mark S LeDoux, Joseph H Friedman, James Polke, Robin Labrum, Vikram Shakkottai, Hayley S McLoughlin, Henry L Paulson, Takuya Konno, Osamu Onodera, Takeshi Ikeuchi, Mari Tada, Akiyoshi Kakita, John D Fryer, Christin Karremo, Inês Gomes, John N Caviness, Mark R Pittelkow, Jan Aasly, Ronald F Pfeiffer, Venka Veerappan, Eric R Eggenberger, William D Freeman, Josephine F Huang, Ryan J Uitti, Klaas J Wierenga, Iris V Marin Collazo, Philip W Tipton, Jay A van Gerpen, Marka van Blitterswijk, Guojun Bu, Zbigniew K Wszolek, Paola Giunti, Leonard Petrucelli

Science translational medicine 12 ( 566 ) 2020年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Spinocerebellar ataxia type 3 (SCA3), caused by a CAG repeat expansion in the ataxin-3 gene (ATXN3), is characterized by neuronal polyglutamine (polyQ) ATXN3 protein aggregates. Although there is no cure for SCA3, gene-silencing approaches to reduce toxic polyQ ATXN3 showed promise in preclinical models. However, a major limitation in translating putative treatments for this rare disease to the clinic is the lack of pharmacodynamic markers for use in clinical trials. Here, we developed an immunoassay that readily detects polyQ ATXN3 proteins in human biological fluids and discriminates patients with SCA3 from healthy controls and individuals with other ataxias. We show that polyQ ATXN3 serves as a marker of target engagement in human fibroblasts, which may bode well for its use in clinical trials. Last, we identified a single-nucleotide polymorphism that strongly associates with the expanded allele, thus providing an exciting drug target to abrogate detrimental events initiated by mutant ATXN3. Gene-silencing strategies for several repeat diseases are well under way, and our results are expected to improve clinical trial preparedness for SCA3 therapies.

DOI： 10.1126/scitranslmed.abb7086

Arginine is a disease modifier for polyQ disease models that stabilizes polyQ protein conformation. 査読国際誌

Eiko N Minakawa, Helena Akiko Popiel, Masayoshi Tada, Toshiaki Takahashi, Hiroshi Yamane, Yuji Saitoh, Yasuo Takahashi, Daisaku Ozawa, Akiko Takeda, Toshihide Takeuchi, Yuma Okamoto, Kazuhiro Yamamoto, Mari Suzuki, Hiromi Fujita, Chiyomi Ito, Hiroko Yagihara, Yuko Saito, Kei Watase, Hiroaki Adachi, Masahisa Katsuno, Hideki Mochizuki, Kentaro Shiraki, Gen Sobue, Tatsushi Toda, Keiji Wada, Osamu Onodera, Yoshitaka Nagai

Brain : a journal of neurology 143 ( 6 ) 1811 - 1825 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

The polyglutamine (polyQ) diseases are a group of inherited neurodegenerative diseases that include Huntington's disease, various spinocerebellar ataxias, spinal and bulbar muscular atrophy, and dentatorubral pallidoluysian atrophy. They are caused by the abnormal expansion of a CAG repeat coding for the polyQ stretch in the causative gene of each disease. The expanded polyQ stretches trigger abnormal β-sheet conformational transition and oligomerization followed by aggregation of the polyQ proteins in the affected neurons, leading to neuronal toxicity and neurodegeneration. Disease-modifying therapies that attenuate both symptoms and molecular pathogenesis of polyQ diseases remain an unmet clinical need. Here we identified arginine, a chemical chaperone that facilitates proper protein folding, as a novel compound that targets the upstream processes of polyQ protein aggregation by stabilizing the polyQ protein conformation. We first screened representative chemical chaperones using an in vitro polyQ aggregation assay, and identified arginine as a potent polyQ aggregation inhibitor. Our in vitro and cellular assays revealed that arginine exerts its anti-aggregation property by inhibiting the toxic β-sheet conformational transition and oligomerization of polyQ proteins before the formation of insoluble aggregates. Arginine exhibited therapeutic effects on neurological symptoms and protein aggregation pathology in Caenorhabditis elegans, Drosophila, and two different mouse models of polyQ diseases. Arginine was also effective in a polyQ mouse model when administered after symptom onset. As arginine has been safely used for urea cycle defects and for mitochondrial myopathy, encephalopathy, lactic acid and stroke syndrome patients, and efficiently crosses the blood-brain barrier, a drug-repositioning approach for arginine would enable prompt clinical application as a promising disease-modifier drug for the polyQ diseases.

DOI： 10.1093/brain/awaa115

Effect of rovatirelin in patients with cerebellar ataxia: two randomised double-blind placebo-controlled phase 3 trials. 査読国際誌

Masatoyo Nishizawa, Osamu Onodera, Akihiro Hirakawa, Yoshitaka Shimizu, Masayuki Yamada

Journal of neurology, neurosurgery, and psychiatry 91 ( 3 ) 254 - 262 2020年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

OBJECTIVE: To investigate the efficacy of rovatirelin, a thyrotropin-releasing hormone analogue, for ataxias in patients with spinocerebellar degeneration (SCD). METHODS: Two multicentre, randomised, double-blind, placebo-controlled phase 3 studies (KPS1301, KPS1305) enrolled patients with predominant cerebellar ataxia, including SCA6, SCA31 or cortical cerebellar atrophy. KPS1301 enrolled patients with truncal ataxia and KPS1305 enrolled patients with truncal and limb ataxia. Each study included 4 weeks of pretreatment, a 28-week or 24-week treatment period and 4 weeks of follow-up. Patients were randomised (1:1:1) to rovatirelin (1.6 or 2.4 mg) or placebo in KPS1301, and randomised (1:1) to rovatirelin 2.4 mg or placebo in KPS1305. The primary endpoint was change in Scale for the Assessment and Rating of Ataxia (SARA) total scores. Pooled analysis was performed in patients who met the SARA recruitment criteria of KPS1305. RESULTS: From October 2013 to May 2014, KPS1301 enrolled 411 patients; 374 were randomised to rovatirelin 1.6 mg (n=125), rovatirelin 2.4 mg (n=126) or placebo (n=123). From November 2016 to August 2017, KPS1305 enrolled 241 patients; 203 were randomised to rovatirelin 2.4 mg (n=101) or placebo (n=102). The primary endpoint showed no significant difference between rovatirelin and placebo in these two studies. In the pooled analysis (n=278), the difference between rovatirelin 2.4 mg (n=140) and placebo (n=138) was -0.61 (-1.64 vs -1.03; 95% CI -1.16 to -0.06; p=0.029) in the adjusted mean change in the SARA total score. CONCLUSIONS: Rovatirelin is a potentially effective treatment option for SCD. TRIAL REGISTRATION NUMBER: NCT01970098; NCT02889302.

DOI： 10.1136/jnnp-2019-322168

Amyotrophic Lateral Sclerosis with Pallidonigroluysian Degeneration: A Clinicopathological Study. 査読国際誌

Junko Ito, Hiroshi Shimizu, Kentaro Ohta, Jiro Idezuka, Hajime Tanaka, Hiroshi Kondo, Takashi Nakajima, Hitoshi Takahashi, Kohei Akazawa, Osamu Onodera, Akiyoshi Kakita

Annals of neurology 87 ( 2 ) 302 - 312 2020年2月

記述言語：英語掲載種別：研究論文（学術雑誌）

OBJECTIVE: The pallidonigroluysian (PNL) system, the primary component of corticosubcortical circuits, is generally spared in amyotrophic lateral sclerosis (ALS). We evaluated the clinicopathological features of an unusual form of ALS with PNL degeneration (PNLD) and assessed whether ALS with PNLD represents a distinct ALS subtype. METHODS: From a cohort of 97 autopsied cases of sporadic ALS with phosphorylated 43kDa TAR DNA-binding protein (TDP-43) inclusions, we selected those with PNLD and analyzed their clinicopathological features. RESULTS: Eleven cases (11%) that showed PNLD were divided into 2 subtypes depending on the lesion distribution: (1) extensive type (n = 6), showing widespread TDP-43 pathology and multisystem degeneration, both involving the PNL system; and (2) limited type (n = 5), showing selective PNL and motor system involvement, thus being unclassifiable in terms of Brettschneider's staging or Nishihira's typing of ALS. The limited type showed a younger age at onset and predominant PNLD that accounted for the early development of extrapyramidal signs. The limited type exhibited the heaviest pathology in the subthalamus and external globus pallidus, suggesting that TDP-43 inclusions propagated via indirect or hyperdirect pathways, unlike ALS without PNLD, where the direct pathway is considered to convey TDP-43 aggregates from the cerebral cortex to the substantia nigra. INTERPRETATION: The PNL system can be involved in the disease process of ALS, either nonselectively as part of multisystem degeneration, or selectively. ALS with selective involvement of the PNL and motor systems exhibits unique clinicopathological features and TDP-43 propagation routes, thus representing a distinct subtype of ALS. ANN NEUROL 2020;87:302-312.

DOI： 10.1002/ana.25652

HTRA1-Related Cerebral Small Vessel Disease: A Review of the Literature. 査読国際誌

Masahiro Uemura, Hiroaki Nozaki, Taisuke Kato, Akihide Koyama, Naoko Sakai, Shoichiro Ando, Masato Kanazawa, Nozomi Hishikawa, Yoshinori Nishimoto, Kiran Polavarapu, Atchayaram Nalini, Akira Hanazono, Daisuke Kuzume, Akihiro Shindo, Mohammad El-Ghanem, Arata Abe, Aki Sato, Mari Yoshida, Takeshi Ikeuchi, Ikuko Mizuta, Toshiki Mizuno, Osamu Onodera

Frontiers in neurology 11 545 - 545 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is clinically characterized by early-onset dementia, stroke, spondylosis deformans, and alopecia. In CARASIL cases, brain magnetic resonance imaging reveals severe white matter hyperintensities (WMHs), lacunar infarctions, and microbleeds. CARASIL is caused by a homozygous mutation in high-temperature requirement A serine peptidase 1 (HTRA1). Recently, it was reported that several heterozygous mutations in HTRA1 also cause cerebral small vessel disease (CSVD). Although patients with heterozygous HTRA1-related CSVD (symptomatic carriers) are reported to have a milder form of CARASIL, little is known about the clinical and genetic differences between the two diseases. Given this gap in the literature, we collected clinical information on HTRA1-related CSVD from a review of the literature to help clarify the differences between symptomatic carriers and CARASIL and the features of both diseases. Forty-six symptomatic carriers and 28 patients with CARASIL were investigated. Twenty-eight mutations in symptomatic carriers and 22 mutations in CARASIL were identified. Missense mutations in symptomatic carriers are more frequently identified in the linker or loop 3 (L3)/loop D (LD) domains, which are critical sites in activating protease activity. The ages at onset of neurological symptoms/signs were significantly higher in symptomatic carriers than in CARASIL, and the frequency of characteristic extraneurological findings and confluent WMHs were significantly higher in CARASIL than in symptomatic carriers. As previously reported, heterozygous HTRA1-related CSVD has a milder clinical presentation of CARASIL. It seems that haploinsufficiency can cause CSVD among symptomatic carriers according to the several patients with heterozygous nonsense/frameshift mutations. However, the differing locations of mutations found in the two diseases indicate that distinct molecular mechanisms influence the development of CSVD in patients with HTRA1-related CSVD. These findings further support continued careful examination of the pathogenicity of mutations located outside the linker or LD/L3 domain in symptomatic carriers.

DOI： 10.3389/fneur.2020.00545

Non-genetically modified models exhibit TARDBP mRNA increase due to perturbed TDP-43 autoregulation. 査読国際誌

Akihiro Sugai, Taisuke Kato, Akihide Koyama, Yuka Koike, Takuya Konno, Tomohiko Ishihara, Osamu Onodera

Neurobiology of disease 130 104534 - 104534 2019年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by accumulation of fragmented insoluble TDP-43 and loss of TDP-43 from the nucleus. Increased expression of exogenous TARDBP (encoding TDP-43) induces TDP-43 pathology and cytotoxicity, suggesting the involvement of aberrant expression of TDP-43 in the pathogenesis of ALS. In normal conditions, however, the amount of TDP-43 is tightly regulated by the autoregulatory mechanism involving alternative splicing of TARDBP mRNA. To investigate the influence of autoregulation dysfunction, we inhibited the splicing of cryptic intron 6 using antisense oligonucleotides in vivo. This inhibition doubled the Tardbp mRNA expression, increased the fragmented insoluble TDP-43, and reduced the number of motor neurons in the mouse spinal cord. In human induced pluripotent stem cell-derived neurons, the splicing inhibition of intron 6 increased TARDBP mRNA and decreased nuclear TDP-43. These non-genetically modified models exhibiting rise in the TARDBP mRNA levels suggest that TDP-43 autoregulation turbulence might be linked to the pathogenesis of ALS.

DOI： 10.1016/j.nbd.2019.104534

Retinal Vasculopathy With Cerebral Leukodystrophy: Clinicopathologic Features of an Autopsied Patient With a Heterozygous TREX 1 Mutation. 査読国際誌

Rie Saito, Hiroaki Nozaki, Taisuke Kato, Yasuko Toyoshima, Hajime Tanaka, Yutaka Tsubata, Tetsuo Morioka, Yoh Horikawa, Kiyomitsu Oyanagi, Takashi Morita, Osamu Onodera, Akiyoshi Kakita

Journal of neuropathology and experimental neurology 78 ( 2 ) 181 - 186 2019年2月

記述言語：英語

Retinal vasculopathy with cerebral leukodystrophy (RVCL) is an autosomal-dominant disorder involving the cerebral, retinal, renal, and other systemic microvessels due to frameshift mutations in the TREX1 gene. Under physiological conditions, the TREX1 protein is localized in the cellular cytoplasm and perinuclear area, but translocates into the nucleus in response to oxidative DNA damage. It has been speculated that aberrant localization of the protein may be associated with systemic microangiopathy in patients with RVCL. However, cellular expression of TREX1 in the brain and visceral organs of patients with RVCL has been unclear. Here, we report the clinicopathologic features of an autopsied patient with a heterozygous T249fs mutation in TREX1. The patient showed the clinical phenotype of vasculopathy with retinopathy, nephropathy, and stroke. CT with contrast enhancement demonstrated a tumorous lesion in the subcortical white matter. Histologically, the lesion consisted of confluent foci of necrosis with calcification and fibrous thickening of small vessel walls. TREX1 immunohistochemistry demonstrated positivity in the nuclei of cells in the CNS and visceral organs, indicating aberrant localization of the truncated protein, and the expression was remarkable in oligodendrocytes within the lesion, suggesting possible involvement of the protein in the pathomechanism of vasculopathy leading to white matter degeneration.

DOI： 10.1093/jnen/nly115

HTRA1 Mutations Identified in Symptomatic Carriers Have the Property of Interfering the Trimer-Dependent Activation Cascade. 査読国際誌

Masahiro Uemura, Hiroaki Nozaki, Akihide Koyama, Naoko Sakai, Shoichiro Ando, Masato Kanazawa, Taisuke Kato, Osamu Onodera

Frontiers in neurology 10 693 - 693 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）

Background: Mutations in the high-temperature requirement A serine peptidase 1 (HTRA1) cause cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). Most carriers for HTRA1 mutations are asymptomatic, but more than 10 mutations have been reported in symptomatic carriers. The molecular differences between the mutations identified in symptomatic carriers and mutations identified only in CARASIL patients are unclear. HTRA1 is a serine protease that forms homotrimers, with each HTRA1 subunit activating the adjacent HTRA1 via the sensor domain of loop 3 (L3) and the activation domain of loop D (LD). Previously, we analyzed four HTRA1 mutant proteins identified in symptomatic carriers and found that they were unable to form trimers or had mutations in the LD or L3 domain. The mutant HTRA1s with these properties are presumed to inhibit trimer-dependent activation cascade. Indeed, these mutant HTRA1s inhibited wild-type (WT) protease activity. In this study, we further analyzed 15 missense HTRA1s to clarify the molecular character of mutant HTRA1s identified in symptomatic carriers. Methods: We analyzed 12 missense HTRA1s identified in symptomatic carriers (hetero-HTRA1) and three missense HTRA1s found only in CARASIL (CARASIL-HTRA1). The protease activity of the purified recombinant mutant HTRA1s was measured using fluorescein isothiocyanate-labeled casein as substrate. Oligomeric structure was evaluated by size-exclusion chromatography. The protease activities of mixtures of WT with each mutant HTRA1 were also measured. Results: Five hetero-HTRA1s had normal protease activity and were excluded from further analysis. Four of the seven hetero-HTRA1s and one of the three CARASIL-HTRA1s were unable to form trimers. The other three hetero-HTRA1s had mutations in the LD domain. Together with our previous work, 10 of 11 hetero-HTRA1s and two of six CARASIL-HTRA1s were either defective in trimerization or had mutations in the LD or L3 domain (P = 0.006). By contrast, eight of 11 hetero-HTRA1s and two of six CARASIL-HTRA1 inhibited WT protease activity (P = 0.162). Conclusions: HTRA1 mutations identified in symptomatic carriers have the property of interfering the trimer-dependent activation cascade of HTRA1.

DOI： 10.3389/fneur.2019.00693

Robustness and Vulnerability of the Autoregulatory System That Maintains Nuclear TDP-43 Levels: A Trade-off Hypothesis for ALS Pathology Based on in Silico Data. 査読国際誌

Akihiro Sugai, Taisuke Kato, Akihide Koyama, Yuka Koike, Sou Kasahara, Takuya Konno, Tomohiko Ishihara, Osamu Onodera

Frontiers in neuroscience 12 28 - 28 2018年

記述言語：英語掲載種別：研究論文（学術雑誌）

Abnormal accumulation of TAR DNA-binding protein 43 (TDP-43) in the cytoplasm and its disappearance from the nucleus are pathological features of amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD) and are directly involved in the pathogenesis of these conditions. TDP-43 is an essential nuclear protein that readily aggregates in a concentration-dependent manner. Therefore, cells must strictly maintain an appropriate amount of nuclear TDP-43. In one relevant maintenance mechanism, TDP-43 binds to its pre-mRNA and promotes alternative splicing, resulting in mRNA degradation via nonsense-mediated mRNA decay. The level of nuclear TDP-43 is tightly regulated by these mechanisms, which control the amount of mRNA that may be translated. Based on the results of previous experiments, we developed an in silico model that mimics the intracellular dynamics of TDP-43 and examined TDP-43 metabolism under various conditions. We discovered an inherent trade-off in this mechanism between transcriptional redundancy, which maintains the robustness of TDP-43 metabolism, and vulnerability to specific interfering factors. These factors include an increased tendency of TDP-43 to aggregate, impaired nuclear-cytoplasmic TDP-43 transport, and a decreased efficiency of degrading abnormal proteins, all of which are functional abnormalities related to the gene that causes familial ALS/FTD. When these conditions continue at a certain intensity, the vulnerability of the autoregulatory machinery becomes apparent over time, and transcriptional redundancy enters a vicious cycle that ultimately results in TDP-43 pathology. The results obtained using this in silico model reveal the difference in TDP-43 metabolism between normal and disease states. Furthermore, using this model, we simulated the effect of a decrease in TDP-43 transcription and found that this decrease improved TDP-43 pathology and suppressed the abnormal propagation of TDP-43. Therefore, we propose a potential therapeutic strategy to suppress transcriptional redundancy, which is the driving force of the pathological condition caused by the specific factors described above, in patients with ALS presenting with TDP-43 pathology. An ALS animal model exhibiting TDP-43 pathology without overexpression of exogenous TDP-43 should be developed to investigate the effect of alleviating the transcriptional redundancy of TARDBP.

DOI： 10.3389/fnins.2018.00028

Increased cytoplasmic TARDBP mRNA in affected spinal motor neurons in ALS caused by abnormal autoregulation of TDP-43 査読

Akihide Koyama, Akihiro Sugai, Taisuke Kato, Tomohiko Ishihara, Atsushi Shiga, Yasuko Toyoshima, Misaki Koyama, Takuya Konno, Sachiko Hirokawa, Akio Yokoseki, Masatoyo Nishizawa, Akiyoshi Kakita, Hitoshi Takahashi, Osamu Onodera

NUCLEIC ACIDS RESEARCH 44 ( 12 ) 5820 - 5836 2016年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder. In motor neurons of ALS, TAR DNA binding protein-43 (TDP-43), a nuclear protein encoded by TARDBP, is absent from the nucleus and forms cytoplasmic inclusions. TDP-43 auto-regulates the amount by regulating the TARDBP mRNA, which has three polyadenylation signals (PASs) and three additional alternative introns within the last exon. However, it is still unclear how the autoregulatory mechanism works and how the status of autoregulation in ALS motor neurons without nuclear TDP-43 is. Here we show that TDP-43 inhibits the selection of the most proximal PAS and induces splicing of multiple alternative introns in TARDBP mRNA to decrease the amount of cytoplasmic TARDBP mRNA by nonsense-mediated mRNA decay. When TDP-43 is depleted, the TARDBP mRNA uses the most proximal PAS and is increased in the cytoplasm. Finally, we have demonstrated that in ALS motor neurons-especially neurons with mislocalized TDP-43-the amount of TARDBP mRNA is increased in the cytoplasm. Our observations indicate that nuclear TDP-43 contributes to the autoregulation and suggests that the absence of nuclear TDP-43 induces an abnormal autoregulation and increases the amount of TARDBP mRNA. The vicious cycle might accelerate the disease progression of ALS.

DOI： 10.1093/nar/gkw499

Distinct molecular mechanisms of HTRA1 mutants in manifesting heterozygotes with CARASIL. 査読国際誌

Hiroaki Nozaki, Taisuke Kato, Megumi Nihonmatsu, Yohei Saito, Ikuko Mizuta, Tomoko Noda, Ryoko Koike, Kazuhide Miyazaki, Muichi Kaito, Shoichi Ito, Masahiro Makino, Akihide Koyama, Atsushi Shiga, Masahiro Uemura, Yumi Sekine, Ayuka Murakami, Suzuko Moritani, Kenju Hara, Akio Yokoseki, Ryozo Kuwano, Naoto Endo, Takeshi Momotsu, Mari Yoshida, Masatoyo Nishizawa, Toshiki Mizuno, Osamu Onodera

Neurology 86 ( 21 ) 1964 - 74 2016年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

OBJECTIVE: To elucidate the molecular mechanism of mutant HTRA1-dependent cerebral small vessel disease in heterozygous individuals. METHODS: We recruited 113 unrelated index patients with clinically diagnosed cerebral small vessel disease. The coding sequences of the HTRA1 gene were analyzed. We evaluated HTRA1 protease activities using casein assays and oligomeric HTRA1 formation using gel filtration chromatography. RESULTS: We found 4 heterozygous missense mutations in the HTRA1 gene (p.G283E, p.P285L, p.R302Q, and p.T319I) in 6 patients from 113 unrelated index patients and in 2 siblings in 2 unrelated families with p.R302Q. The mean age at cognitive impairment onset was 51.1 years. Spondylosis deformans was observed in all cases, whereas alopecia was observed in 3 cases; an autopsied case with p.G283E showed arteriopathy in their cerebral small arteries. These mutant HTRA1s showed markedly decreased protease activities and inhibited wild-type HTRA1 activity, whereas 2 of 3 mutant HTRA1s reported in cerebral autosomal-recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) (A252T and V297M) did not inhibit wild-type HTRA1 activity. Wild-type HTRA1 forms trimers; however, G283E and T319I HTRA1, observed in manifesting heterozygotes, did not form trimers. P285L and R302Q HTRA1s formed trimers, but their mutations were located in domains that are important for trimer-associated HTRA1 activation; in contrast, A252T and V297M HTRA1s, which have been observed in CARASIL, also formed trimers but had mutations outside the domains important for trimer-associated HTRA1 activation. CONCLUSIONS: The mutant HTRA1s observed in manifesting heterozygotes might result in an impaired HTRA1 activation cascade of HTRA1 or be unable to form stable trimers.

DOI： 10.1212/WNL.0000000000002694

Characteristic features and progression of abnormalities on MRI for CARASIL 査読

Hiroaki Nozaki, Yumi Sekine, Toshio Fukutake, Yoshinori Nishimoto, Yutaka Shimoe, Akiko Shirata, Sohei Yanagawa, Mikio Hirayama, Masato Tamura, Masatoyo Nishizawa, Osamu Onodera

NEUROLOGY 85 ( 5 ) 459 - 463 2015年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：LIPPINCOTT WILLIAMS & WILKINS

Objectives:The objective of this study was to clarify the characteristic brain MRI findings for genetically diagnosed CARASIL (cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy).Methods:Seven patients with CARASIL carrying HTRA1 mutations (representing 6 Japanese families) were included in this study. Eighteen brain MRIs were reviewed and evaluated with a new rating scale based on scoring for abnormal hyperintense lesions and atrophy.Results:At the last follow-up MRI, all patients had hyperintense lesions on T2-weighted images of the frontal white matter, anterior temporal lobe, external capsules, and thalami. Patients with longer time from the onset of cognitive impairment had higher MRI severity score. The atrophy advanced, followed by white matter lesion progression. During the early stage, hyperintense lesions were observed in the frontal white matter, external capsule, and pons. During the late stage, the arc-shaped hyperintense lesion from the pons to the middle cerebellar peduncles, which we designated the arc sign, became evident. The arc sign was a characteristic finding for CARASIL in the advanced stage.Conclusions:These characteristic MRI findings for CARASIL are useful for selecting patients for genetic testing. The rating scale correlates well with disease duration and might be useful for assessing disease progression.

DOI： 10.1212/WNL.0000000000001803

Decreased number of Gemini of coiled bodies and U12 snRNA level in amyotrophic lateral sclerosis 査読

Tomohiko Ishihara, Yuko Ariizumi, Atsushi Shiga, Taisuke Kato, Chun-Feng Tan, Tatsuya Sato, Yukari Miki, Mariko Yokoo, Takeshi Fujino, Akihide Koyama, Akio Yokoseki, Masatoyo Nishizawa, Akiyoshi Kakita, Hitoshi Takahashi, Osamu Onodera

HUMAN MOLECULAR GENETICS 22 ( 20 ) 4136 - 4147 2013年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Disappearance of TAR-DNA-binding protein 43 kDa (TDP-43) from the nucleus contributes to the pathogenesis of amyotrophic lateral sclerosis (ALS), but the nuclear function of TDP-43 is not yet fully understood. TDP-43 associates with nuclear bodies including Gemini of coiled bodies (GEMs). GEMs contribute to the biogenesis of uridine-rich small nuclear RNA (U snRNA), a component of splicing machinery. The number of GEMs and a subset of U snRNAs decrease in spinal muscular atrophy, a lower motor neuron disease, suggesting that alteration of U snRNAs may also underlie the molecular pathogenesis of ALS. Here, we investigated the number of GEMs and U11/12-type small nuclear ribonucleoproteins (snRNP) by immunohistochemistry and the level of U snRNAs using real-time quantitative RT-PCR in ALS tissues. GEMs decreased in both TDP-43-depleted HeLa cells and spinal motor neurons in ALS patients. Levels of several U snRNAs decreased in TDP-43-depleted SH-SY5Y and U87-MG cells. The level of U12 snRNA was decreased in tissues affected by ALS (spinal cord, motor cortex and thalamus) but not in tissues unaffected by ALS (cerebellum, kidney and muscle). Immunohistochemical analysis revealed the decrease in U11/12-type snRNP in spinal motor neurons of ALS patients. These findings suggest that loss of TDP-43 function decreases the number of GEMs, which is followed by a disturbance of pre-mRNA splicing by the U11/U12 spliceosome in tissues affected by ALS.

DOI： 10.1093/hmg/ddt262

MRI Features of Cerebral Autosomal Recessive Arteriopathy with Subcortical Infarcts and Leukoencephalopathy 査読

Hiroaki Nozaki, Yumi Sekine, Toshio Fukutake, Yoshinori Nishimoto, Mamoru Shibata, Shimoe Yutaka, Akiko Shirata, Sohei Yanagawa, Mikio Hirayama, Kiyomi Yamane, Imaharu Nakano, Norihiro Suzuki, Masatoyo Nishizawa, Osamu Onodera

NEUROLOGY 80 560 - 566 2013年2月

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