Hideki Mochizuki

Publications (92)355.28 Total impact

• Article: Lewy Body Pathology in a Patient with a Homozygous Parkin Deletion.

  Saori Miyakawa, Mieko Ogino, Sayaka Funabe, Akiko Uchino, Yasushi Shimo, Nobutaka Hattori, Masaaki Ichinoe, Tetuo Mikami, Makoto Saegusa, Kazutoshi Nishiyama, Hideo Mori, Yoshikuni Mizuno, Shigeo Murayama, Hideki Mochizuki
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  ABSTRACT: BACKGROUND: We report neuropathologic findings in a patient with homozygous deletions of exons 2 to 4 of parkin. RESULTS: Although the absence of Lewy bodies has been considered a neuropathologic characteristic of parkin mutation, here we report a pathologic finding with the presence of Lewy bodies. METHODS: The patient was a 72-year-old woman with onset of the disease at age 61. Her autopsy revealed marked decrease in melanized neurons in the substantia nigra and the locus coeruleus. Lewy bodies were found in the substantia nigra, the locus coeruleus, the dorsal motor nucleus of the vagus, the basal nucleus of Meynert, the amygdaloid nucleus, and the sympathetic nerve bundles in the myocardium. CONCLUSIONS: Only 3 previous case reports described Lewy body formation in patients carrying parkin mutations. The distribution of Lewy bodies in our patient appeared to be reminiscent of sporadic Parkinson's disease. © 2013 Movement Disorder Society.
  Movement Disorders 02/2013; · 4.51 Impact Factor
• Article: A case of chronic active Epstein-Barr virus infection associated with recurrent cerebellar ataxia and skin eruptions.

  Katsuya Araki, Tatsusada Okuno, Josephe Archie Honorat, Makoto Kinoshita, Masanori P Takahashi, Masao Mizuki, Kazuo Kitagawa, Hideki Mochizuki
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  ABSTRACT: A 62-year-old woman presented with subacute cerebellar ataxia, lymph node swelling and skin eruption. Laboratory tests revealed elevated titers of anti-VCA-IgG antibody and anti-EADR-IgG antibody, with Epstein-Barr virus (EBV) DNA detected from the blood and CSF by PCR. Since these data were highlighted with the diagnosis of chronic active EBV infection (CAEBV) and her ataxia improved concomitantly with the remission of other infectious mononucleosis-like symptoms, we supposed her ataxia is associated with CAEBV. Five years later, at the age of 67, her ataxia relapsed concurrently with skin eruptions, whereas MRI demonstrated progression of cerebellar atrophy. After high-dose intravenous methylprednisolone treatment, the clinical symptoms resolved. Initial infection of EBV in childhood often causes autoimmune acute cerebellitis but cerebellar ataxia has rarely been described in CAEBV. Furthermore, immunohistochemical analysis revealed a reactivity of the patient's serum and CSF on rat cerebellum, suggesting an autoimmune pathomechanism for the ataxia.
  Rinshō shinkeigaku = Clinical neurology. 01/2013; 53(2):119-24.
• Article: A case of progressive ataxia and palatal tremor (PAPT) with ear clicks.

  Hiroyuki Sumikura, Tatsusada Okuno, Masanori P Takahashi, Katsuya Araki, Kazuo Kitagawa, Hideki Mochizuki
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  ABSTRACT: A 71-year-old man noted clicking sounds in the ear. At the age of 75, he developed progressive unsteadiness of gait and became unable to walk without assistance at the age of 76. There was no family history of neurologic illness. Neurological examination revealed truncal ataxia and 1-2 Hz rhythmic palatal tremor, which persisted during sleep. Consistently, brain magnetic resonance imaging showed mild cerebellar atrophy and increased signal intensity of bilateral inferior olivary nuclei on T2-weighted image. progressive ataxia and palatal tremor (PAPT) has recently been described as a rare sporadic neurodegenerative disease and the features of our case consistent with those of PAPT. However, for correct diagnosis of PAPT, multiple system atrophy, spinocerebellar ataxia, progressive supranuclear palsy or adult-onset Alexander's disease should be carefully ruled out.
  Rinshō shinkeigaku = Clinical neurology. 01/2013; 53(3):224-8.
• Article: Accumulation of α-Synuclein Triggered by Presynaptic Dysfunction.

  Yasuto Nakata, Toru Yasuda, Masahiro Fukaya, Saori Yamamori, Makoto Itakura, Tomoko Nihira, Hideki Hayakawa, Aya Kawanami, Masakazu Kataoka, Makiko Nagai, Hiroyuki Sakagami, Masami Takahashi, Yoshikuni Mizuno, Hideki Mochizuki
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  ABSTRACT: Pathological examination of dementia with Lewy bodies patients identified the presence of abnormal α-synuclein (αSyn) aggregates in the presynaptic terminals. αSyn is involved in the regulation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. Importantly, αSyn-transgenic mouse and postmortem examination of patients with Parkinson's disease have demonstrated the abnormal distribution of SNARE protein in presynaptic terminals. In this study, we investigated the effects of SNARE dysfunction on endogenous αSyn using Snap25(S187A/S187A) mutant mice. These mice have homozygous knock-in gene encoding unphosphorylatable S187A-substituted synaptosomal-associated protein of 25 kDa (SNAP-25). The mice displayed a significant age-dependent change in the distribution of αSyn and its Ser(129)-phosphorylated form in abnormally hypertrophied glutamatergic nerve terminals in the striatum. Electron-microscopic analysis revealed the abnormally condensed synaptic vesicles with concomitant mislocalization of αSyn protein to the periactive zone in the glutamatergic nerve terminals. However, the Snap25(S187A/S187A) mutant mouse harbored no abnormalities in the nigrostriatal dopaminergic neurons. Our present results suggest that SNARE dysfunction is the initial trigger of mislocalization and accumulation of αSyn, and probably is an important pathomechanism of α-synucleinopathies.
  Journal of Neuroscience 11/2012; 32(48):17186-96. · 7.11 Impact Factor
• Article: Iron accumulation in Parkinson's disease.

  Hideki Mochizuki, Toru Yasuda
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  ABSTRACT: Although the exact cause of Parkinson's disease (PD) is still unknown, recent interest has been focused on the role of iron in the nigral cell death in PD. Several studies have shown that a selective and significant elevation in iron occurs in the substantia nigra of patients with PD. However, the mechanisms involved in iron accumulation also remain unclear. In this article, we describe recent findings regarding the mechanisms and potential toxic effects of iron accumulation in hereditary and sporadic PD and animal models of PD, including our genetic mouse model of PD. The review provides an opportunity to revisit the possible roles of iron accumulation in the pathogenic cascade(s) of PD.
  Acta Neurovegetativa 10/2012; · 2.73 Impact Factor
• Article: Angiogenesis induced by CNS inflammation promotes neuronal remodeling through vessel-derived prostacyclin.

  Rieko Muramatsu, Chisato Takahashi, Shuzo Miyake, Harutoshi Fujimura, Hideki Mochizuki, Toshihide Yamashita
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  ABSTRACT: Angiogenesis is a prominent feature of central nervous system (CNS) disease and has roles in both the continued promotion of inflammation and the subsequent repair processes. Here we report that prostacyclin (or prostaglandin I(2) (PGI(2))) derived from new vessels promotes axonal remodeling of injured neuronal networks after CNS inflammation. In a localized model of experimental autoimmune encephalomyelitis (EAE), new vessels formed around the inflammatory lesion, followed by sprouting of adjacent corticospinal tract (CST) fibers. These sprouting fibers formed a compensatory motor circuit, leading to recovery of motor function. Capillary endothelial cell-derived prostacyclin bound to its receptor, the type I prostaglandin receptor (IP receptor), on CST neurons, promoting sprouting of CST fibers and contributing to the repair process. Inhibition of prostacyclin receptor signaling impaired motor recovery, whereas the IP receptor agonist iloprost promoted axonal remodeling and motor recovery after the induction of EAE. These findings reveal an important function of angiogenesis in neuronal rewiring and suggest that prostacyclin is a promising molecule for enhancing functional recovery from CNS disease.
  Nature medicine 10/2012; · 27.14 Impact Factor
• Article: Mitochondrial dysfunction associated with increased oxidative stress and alpha-synuclein accumulation in PARK2 iPSC-derived neurons and postmortem brain tissue.

  Yoichi Imaizumi, Yohei Okada, Wado Akamatsu, Masato Koike, Naoko Kuzumaki, Hideki Hayakawa, Tomoko Nihira, Tetsuro Kobayashi, Manabu Ohyama, Shigeto Sato, [......], Masanobu Shouji, Atsushi Nakanishi, Norihiro Suzuki, Yoshikuni Mizuno, Noboru Mizushima, Masayuki Amagai, Yasuo Uchiyama, Hideki Mochizuki, Nobutaka Hattori, Hideyuki Okano
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  ABSTRACT: BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disease characterized by selective degeneration of dopaminergic neurons in the substantia nigra (SN). The familial form of PD, PARK2, is caused by mutations in the parkin gene. parkin-knockout mouse models show some abnormalities, but they do not fully recapitulate the pathophysiology of human PARK2. RESULTS: Here, we generated induced pluripotent stem cells (iPSCs) from two PARK2 patients. PARK2 iPSC-derived neurons showed increased oxidative stress and enhanced activity of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. iPSC-derived neurons, but not fibroblasts or iPSCs, exhibited abnormal mitochondrial morphology and impaired mitochondrial homeostasis. Although PARK2 patients rarely exhibit Lewy body (LB) formation with an accumulation of alpha-synuclein, alpha-synuclein accumulation was observed in the postmortem brain of one of the donor patients. This accumulation was also seen in the iPSC-derived neurons in the same patient. CONCLUSIONS: Thus, pathogenic changes in the brain of a PARK2 patient were recapitulated using iPSC technology. These novel findings reveal mechanistic insights into the onset of PARK2 and identify novel targets for drug screening and potential modified therapies for PD.
  Molecular Brain 10/2012; 5(1):35.
• Article: α-Synuclein and Neuronal Cell Death.

  Toru Yasuda, Yasuto Nakata, Hideki Mochizuki
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  ABSTRACT: Parkinson's disease (PD) is a progressive neurodegenerative disorder affecting ∼1 % of people over the age of 65. Neuropathological hallmarks of PD are prominent loss of dopaminergic (DA) neurons in the substantia nigra and formation of intraneuronal protein inclusions termed Lewy bodies, composed mainly of α-synuclein (αSyn). Missense mutations in αSyn gene giving rise to production of degradation-resistant mutant proteins or multiplication of wild-type αSyn gene allele can cause rare inherited forms of PD. Therefore, the existence of abnormally high amount of αSyn protein is considered responsible for the DA neuronal death in PD. Normally, αSyn protein localizes to presynaptic terminals of neuronal cells, regulating the neurotransmitter release through the modulation of assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex. On the other hand, of note, pathological examinations on the recipient patients of fetal nigral transplants provided a prion-like cell-to-cell transmission hypothesis for abnormal αSyn. The extracellular αSyn fibrils can internalize to the cells and enhance intracellular formation of protein inclusions, thereby reducing cell viability. These findings suggest that effective removal of abnormal species of αSyn in the extracellular space as well as intracellular compartments can be of therapeutic relevance. In this review, we will focus on αSyn-triggered neuronal cell death and provide possible disease-modifying therapies targeting abnormally accumulating αSyn.
  Molecular Neurobiology 08/2012; · 5.74 Impact Factor
• Article: Neuropathologic analysis of Lewy-related α-synucleinopathy in olfactory mucosa.

  Sayaka Funabe, Masaki Takao, Yuko Saito, Hiroyuki Hatsuta, Mikiko Sugiyama, Shinji Ito, Kazutomi Kanemaru, Motoji Sawabe, Tomio Arai, Hideki Mochizuki, Nobutaka Hattori, Shigeo Murayama
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  ABSTRACT: We analyzed the incidence and extent of Lewy-related α-synucleinopathy (LBAS) in the olfactory mucosa, as well as the central and peripheral nervous systems of consecutive autopsy cases from a general geriatric hospital. The brain and olfactory mucosa were immunohistochemically examined using antibodies raised against phosphorylated α-synuclein. Thirty-nine out of 105 patients (37.1%) showed LBAS in the central or peripheral nervous systems. Seven patients presented LBAS (Lewy neurites) in the olfactory lamina propria mucosa. One out of the seven cases also showed a Lewy neurite in a bundle of axons in the cribriform plate, but α-synuclein deposits were not detected in the olfactory receptor neurons. In particular, high incidence of α-synuclein immunopositive LBAS in the olfactory mucosa was present in the individuals with clinically as well as neuropathologically confirmed Parkinson's disease and dementia with Lewy bodies (6/8 cases, 75%). However, this pathologic alteration was rare in the cases with incidental or subclinical Lewy body diseases (LBD) (one out of 31 cases, 3.2%). In the olfactory bulb, the LBAS was usually present in the glomeruli and granular cells of most symptomatic and asymptomatic cases with LBD. Our studies further confirmed importance of the olfactory entry zone in propagation of LBAS in the human aging nervous system.
  Neuropathology 06/2012; · 2.02 Impact Factor
• Article: Gene transfer targeting mouse vestibule using adenovirus and adeno-associated virus vectors.

  Hiroko Okada, Takashi Iizuka, Hideki Mochizuki, Tomoko Nihira, Kazusaku Kamiya, Ayako Inoshita, Hiromi Kasagi, Misato Kasai, Katsuhisa Ikeda
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  ABSTRACT: The present study assessed how to inject a gene into the mouse vestibule and which is the optimum gene to the mouse vestibule adenovirus (AdV) vector or adeno-associated virus (AAV) vector. Loss of vestibular hair cell is seen in various balance disorder diseases. There have been some reports concerning gene delivery to the mouse vestibule in recent years. To effectively induce transgene expression at the vestibule, we assessed the efficiency of inoculating the mouse inner ear using various methods. We employed an AdV- and AAV-carrying green fluorescent protein using a semicircular canal approach (via a canalostomy) and round window approach. AAV injection via canalostomy induced gene expression at the hair cells, supporting cells, and fibrocytes at the vestibular organs without auditory or balance dysfunction, suggesting it was the most suitable transfection method. This method is thus considered to be a promising strategy to prevent balance dysfunction. AAV injection via canalostomy to the vestibule is the noninvasive and highly efficient transfection method, and this study may have the potential to repair balance disorders in human in the future.
  Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 04/2012; 33(4):655-9. · 1.44 Impact Factor
• Article: Elevation of Sema4A implicates Th cell skewing and the efficacy of IFN-β therapy in multiple sclerosis.

  Yuji Nakatsuji, Tatsusada Okuno, Masayuki Moriya, Tomoyuki Sugimoto, Makoto Kinoshita, Hyota Takamatsu, Satoshi Nojima, Tetsuya Kimura, Sujin Kang, Daisuke Ito, [......], Kazushiro Takata, Misa Nakano, Masato Kubo, Sinobu Suzuki, Akiko Matsui-Hasumi, Ayako Uto-Konomi, Atsushi Ogata, Hideki Mochizuki, Saburo Sakoda, Atsushi Kumanogoh
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  ABSTRACT: Multiple sclerosis (MS) is a demyelinating autoimmune disease of the CNS and a leading cause of lasting neurologic disabilities in young adults. Although the precise mechanism remains incompletely understood, Ag presentation and subsequent myelin-reactive CD4(+) T cell activation/differentiation are essential for the pathogenesis of MS. Although semaphorins were initially identified as axon guidance cues during neural development, several semaphorins are crucially involved in various phases of immune responses. Sema4A is one of the membrane-type class IV semaphorins, which we originally identified from the cDNA library of dendritic cell (DC). Sema4A plays critical roles in T cell activation and Th1 differentiation during the course of experimental autoimmune encephalomyelitis, an animal model of MS; however, its pathological involvement in human MS has not been determined. In this study, we report that Sema4A is increased in the sera of patients with MS. The expression of Sema4A is increased on DCs in MS patients and shed from these cells in a metalloproteinase-dependent manner. DC-derived Sema4A is not only critical for Th1 but also for Th17 cell differentiation, and MS patients with high Sema4A levels exhibit Th17 skewing. Furthermore, patients with high Sema4A levels have more severe disabilities and are unresponsive to IFN-β treatment. Taken together, our results suggest that Sema4A is involved in the pathogenesis of MS by promoting Th17 skewing.
  The Journal of Immunology 04/2012; 188(10):4858-65. · 5.79 Impact Factor
• Source

  Available from: Yasuhiro Yasutomi

  Article: Non-human primate model of amyotrophic lateral sclerosis with cytoplasmic mislocalization of TDP-43.

  Azusa Uchida, Hiroki Sasaguri, Nobuyuki Kimura, Mio Tajiri, Takuya Ohkubo, Fumiko Ono, Fumika Sakaue, Kazuaki Kanai, Takashi Hirai, Tatsuhiko Sano, [......], Kyohei Sakaki, Mitsuhiro Enomoto, Yukihiko Hirai, Jiro Kumagai, Yasuhiro Yasutomi, Hideki Mochizuki, Satoshi Kuwabara, Toshiki Uchihara, Hidehiro Mizusawa, Takanori Yokota
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  ABSTRACT: Amyotrophic lateral sclerosis is a fatal neurodegenerative disease characterized by progressive motoneuron loss. Redistribution of transactive response deoxyribonucleic acid-binding protein 43 from the nucleus to the cytoplasm and the presence of cystatin C-positive Bunina bodies are considered pathological hallmarks of amyotrophic lateral sclerosis, but their significance has not been fully elucidated. Since all reported rodent transgenic models using wild-type transactive response deoxyribonucleic acid-binding protein 43 failed to recapitulate these features, we expected a species difference and aimed to make a non-human primate model of amyotrophic lateral sclerosis. We overexpressed wild-type human transactive response deoxyribonucleic acid-binding protein 43 in spinal cords of cynomolgus monkeys and rats by injecting adeno-associated virus vector into the cervical cord, and examined the phenotype using behavioural, electrophysiological, neuropathological and biochemical analyses. These monkeys developed progressive motor weakness and muscle atrophy with fasciculation in distal hand muscles first. They also showed regional cytoplasmic transactive response deoxyribonucleic acid-binding protein 43 mislocalization with loss of nuclear transactive response deoxyribonucleic acid-binding protein 43 staining in the lateral nuclear group of spinal cord innervating distal hand muscles and cystatin C-positive cytoplasmic aggregates, reminiscent of the spinal cord pathology of patients with amyotrophic lateral sclerosis. Transactive response deoxyribonucleic acid-binding protein 43 mislocalization was an early or presymptomatic event and was later associated with neuron loss. These findings suggest that the transactive response deoxyribonucleic acid-binding protein 43 mislocalization leads to α-motoneuron degeneration. Furthermore, truncation of transactive response deoxyribonucleic acid-binding protein 43 was not a prerequisite for motoneuronal degeneration, and phosphorylation of transactive response deoxyribonucleic acid-binding protein 43 occurred after degeneration had begun. In contrast, similarly prepared rat models expressed transactive response deoxyribonucleic acid-binding protein 43 only in the nucleus of motoneurons. There is thus a species difference in transactive response deoxyribonucleic acid-binding protein 43 pathology, and our monkey model recapitulates amyotrophic lateral sclerosis pathology to a greater extent than rodent models, providing a valuable tool for studying the pathogenesis of sporadic amyotrophic lateral sclerosis.
  Brain 03/2012; 135(Pt 3):833-46. · 9.46 Impact Factor
• Article: Neurovascular changes in prolonged migraine aura in FHM with a novel ATP1A2 gene mutation.

  Takahiro Iizuka, Yuji Takahashi, Mayumi Sato, Junko Yonekura, Saori Miyakawa, Motoi Endo, Junichi Hamada, Shinichi Kan, Hideki Mochizuki, Yoshio Momose, Shoji Tsuji, Fumihiko Sakai
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  ABSTRACT: To report cerebral blood flow changes during attacks of hemiplegic migraine with prolonged aura (HMPA) longer than 24 h in patients with familial hemiplegic migraine (FHM) with a novel gene mutation. The authors performed serial neuroimaging studies during acute stage and after recovery of aura symptoms in eight HMPA attacks in two affected individuals of the Japanese family of FHM during a 10-year-observational period. The authors also performed a mutational analysis for all exons of the CACNA1A, ATP1A2 and SCN1A genes in three individuals of this family. Each patient had an individual 'predominantly affected hemisphere,' that is, susceptible to hemiplegia during an HMPA attack. Migraine aura lasted 4 to 12 days. Neuroimaging studies performed on days 1 to 4 showed hyperperfusion in the affected hemisphere contralateral to hemiplegia in five attacks, hypoperfusion in three, middle cerebral artery vasodilation in five and augmented vasogenic leakage with cortical oedema in one. Hyperperfusion developed more frequently than hypoperfusion in the 'predominantly affected hemisphere,' whereas only hypoperfusion developed in the 'non-predominantly affected hemisphere.' All changes were fully reversible. The authors identified a novel heterozygous p.H916L mutation in the ATP1A2 gene in all three individuals. Although the perfusion state could be different depending on the time course of migraine or the timing of scans in relation to cortical spreading depression, prolonged aura symptoms in this family were frequently associated with hyperperfusion and middle cerebral artery vasodilation. Hyperperfusion tended to occur in the 'predominantly affected hemisphere,' but the mechanism of HMPA awaits further investigations on additional cases of FHM2.
  Journal of neurology, neurosurgery, and psychiatry 02/2012; 83(2):205-12. · 4.87 Impact Factor
• Article: Glycine receptor antibodies are detected in progressive encephalomyelitis with rigidity and myoclonus (PERM) but not in saccadic oscillations.

  Takahiro Iizuka, Maria I Leite, Bethan Lang, Patrick Waters, Yoshiaki Urano, Saori Miyakawa, Junichi Hamada, Fumihiko Sakai, Hideki Mochizuki, Angela Vincent
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  ABSTRACT: Glycine receptor (GlyR) antibodies were recently identified in a few patients with progressive encephalomyelitis with rigidity and myoclonus (PERM); none of these patients had antibodies against glutamic acid decarboxylase (GAD). An inhibitory glycinergic transmission defect has also been implicated in the mechanism underlying saccadic oscillations, including ocular flutter or opsoclonus; GlyR antibodies have not been reported in these patients. The purpose was to determine whether GlyR antibodies are found in patients with PERM, ocular flutter syndrome (OFS), and opsoclonus-myoclonus syndrome (OMS). GlyR antibodies were first measured in archived sera and CSF from five patients, including one patient with GAD antibody-positive PERM, two patients with OFS, and two patients with OMS. GlyR antibodies were also measured in archived sera from nine other adult patients with OMS. GlyR antibodies and GAD antibodies were both found at high titers in the serum and CSF of the patient with PERM, and their levels paralleled disease activity over time. GlyR antibodies were not found at significant levels in 13 patients with saccadic oscillations. GlyR and GAD antibodies can co-exist in PERM and follow the clinical course. Although saccadic oscillations are a feature of this condition, GlyR antibodies are not commonly found in patients with isolated saccadic oscillations.
  Journal of Neurology 01/2012; 259(8):1566-73. · 3.47 Impact Factor
• Article: Effect of melatonin on α-synuclein self-assembly and cytotoxicity.

  Kenjiro Ono, Hideki Mochizuki, Tokuhei Ikeda, Tomoko Nihira, Jun-ichi Takasaki, David B Teplow, Masahito Yamada
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  ABSTRACT: α-Synuclein (αS) assembly has been implicated as a critical step in the development of Lewy body diseases such as Parkinson's disease and dementia with Lewy bodies. Melatonin (Mel), a secretory product of the pineal gland, is known to have beneficial effects such as an antioxidant function and neuroprotection. To elucidate whether Mel has an antiassembly effect, here we used circular dichroism spectroscopy, photoinduced crosslinking of unmodified proteins, thioflavin S fluorescence, size exclusion chromatography, electron microscopy and atomic force microscopy to examine the effects of Mel on the αS assembly. We also examined the effects of Mel on αS-induced cytotoxicity by assaying 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide metabolism in αS-treated, primary neuronal cells. Initial studies revealed that Mel blocked αS fibril formation as well as destabilizing preformed αS fibrils. Subsequent evaluation of the assembly-stage specificity of the effect showed that Mel was able to inhibit protofibril formation, oligomerization, and secondary structure transitions. Importantly, Mel decreased αS-induced cytotoxicity. These data suggest a mechanism of action for Mel, inhibition of assembly of toxic polymers and protection of neurons from their effect.
  Neurobiology of aging 11/2011; 33(9):2172-85. · 5.94 Impact Factor
• Article: Parkin-mediated protection of dopaminergic neurons in a chronic MPTP-minipump mouse model of Parkinson disease.

  Toru Yasuda, Hideki Hayakawa, Tomoko Nihira, Yong-Ri Ren, Yasuto Nakata, Makiko Nagai, Nobutaka Hattori, Koichi Miyake, Masahiko Takada, Takashi Shimada, Yoshikuni Mizuno, Hideki Mochizuki
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  ABSTRACT: Loss-of-function mutations in the ubiquitin ligase parkin are the major cause of recessively inherited early-onset Parkinson disease (PD). Impairment of parkin activity caused by nitrosative or dopamine-related modifications may also be responsible for the loss of dopaminergic (DA) neurons in sporadic PD. Previous studies have shown that viral vector-mediated delivery of parkin prevented DA neurodegeneration in several animal models, but little is known about the neuroprotective actions of parkin in vivo. Here, we investigated mechanisms of neuroprotection of overexpressed parkin in a modified long-term mouse model of PD using osmotic minipump administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Recombinant adeno-associated viral vector-mediated intranigral delivery of parkin prevented motor deficits and DA cell loss in the mice. Ser129-phosphorylated α-synuclein-immunoreactive cells were increased in the substantia nigra of parkin-treated mice. Moreover, delivery of parkin alleviated the MPTP-induced decrease of the active phosphorylated form of Akt. On the other hand, upregulation of p53 and mitochondrial alterations induced by chronic MPTP administration were barely suppressed by parkin. These results suggest that the neuroprotective actions of parkin may be impaired in severe PD.
  Journal of Neuropathology and Experimental Neurology 08/2011; 70(8):686-97. · 4.26 Impact Factor
• Article: Adeno-associated viral vector-mediated gene transduction in mesencephalic slice culture.

  Tomoko Nihira, Toru Yasuda, Yukihiko Hirai, Takashi Shimada, Yoshikuni Mizuno, Hideki Mochizuki
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  ABSTRACT: Adeno-associated viral (AAV) vector is a non-pathogenic vehicle that is suitable for the delivery of foreign genes into non-dividing neuronal cells. This vector has been utilized for in vivo neurological research and in clinical trials of gene therapy for neurodegenerative disorders. Viral vector-mediated gene delivery has the limitation that progressive changes in cellular phenotype cannot be monitored in living animals. To visualize living neurons transduced with foreign genes in vitro, we used cultured mesencephalic tissue harboring living dopaminergic (DA) neurons and examined cellular tropism of serotype-1 and serotype-2 AAV vectors in a culture system. The viability of DA neurons was evaluated using transgenic mice carrying enhanced green fluorescent protein under the control of the rat tyrosine hydroxylase (TH) promoter, which enables the visualization of living DA cells in the substantia nigra. Apoptosis of a subset of neuronal cells was noted within one day of culture. After 7 days, the serotype-1 AAV vector had successfully delivered the foreign gene into neurons and astrocytes, and serotype-2 AAV vector was able to transduce TH-positive DA neurons efficiently. Our method should be useful for in vitro investigations of pathological changes in DA neurons following transduction with foreign genes.
  Journal of neuroscience methods 07/2011; 201(1):55-60. · 2.30 Impact Factor
• Article: Compensation of depleted neuronal subsets by new neurons in a local area of the adult olfactory bulb.

  Koshi Murata, Maki Imai, Shigetada Nakanishi, Dai Watanabe, Ira Pastan, Kazuto Kobayashi, Tomoko Nihira, Hideki Mochizuki, Shuichi Yamada, Kensaku Mori, Masahiro Yamaguchi
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  ABSTRACT: In the olfactory bulb (OB), loss of preexisting granule cells (GCs) and incorporation of adult-born new GCs continues throughout life. GCs consist of distinct subsets. Here, we examined whether the loss and incorporation of GC subsets are coordinated in the OB. We classified GCs into mGluR2-expressing and -negative subsets and selectively ablated mGluR2-expressing GCs in a local area of the OB with immunotoxin-mediated cell ablation method. The density of mGluR2-expressing GCs showed considerable recovery within several weeks after the ablation. During recovery, an mGluR2-expressing new GC subset was preferentially incorporated over an mGluR2-negative new GC subset in the area of ablation, whereas the preferential incorporation was not observed in the intact area. The area-specific preferential incorporation of mGluR2-expressing new GCs occurred for BrdU analog- and retrovirus-labeled adult-born cells as well as for neonate-derived transplanted cells. The mGluR2-expressing new GCs in the ablated area were synaptically incorporated into the local bulbar circuit. The spine size of mGluR2-expressing new GCs in the ablated area was larger than that of those in the intact area. In contrast, mGluR2-negative new GCs did not show ablated area-specific spine enlargement. These results indicate that local OB areas have a mechanism to coordinate the loss and incorporation of GC subsets by compensatory incorporation of new GC subsets, which involves subset-specific cellular incorporation and subset-specific regulation of spine size.
  Journal of Neuroscience 07/2011; 31(29):10540-57. · 7.11 Impact Factor
• Article: A case of parkinsonism and dopa-induced severe dyskinesia associated with novel mutation in the GTP cyclohydrolase I gene.

  Sachiko Irie, Naomi Kanazawa, Masafuchi Ryoh, Hideki Mochizuki, Yoshiko Nomura, Masaya Segawa
  Parkinsonism & Related Disorders 07/2011; 17(10):769-70. · 3.80 Impact Factor
• Article: RGMa modulates T cell responses and is involved in autoimmune encephalomyelitis.

  Rieko Muramatsu, Takekazu Kubo, Masahiro Mori, Yuka Nakamura, Yuki Fujita, Tsugio Akutsu, Tatsusada Okuno, Junko Taniguchi, Atsushi Kumanogoh, Mari Yoshida, Hideki Mochizuki, Satoshi Kuwabara, Toshihide Yamashita
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  ABSTRACT: In multiple sclerosis, activated CD4(+) T cells initiate an immune response in the brain and spinal cord, resulting in demyelination, degeneration and progressive paralysis. Repulsive guidance molecule-a (RGMa) is an axon guidance molecule that has a role in the visual system and in neural tube closure. Our study shows that RGMa is expressed in bone marrow-derived dendritic cells (BMDCs) and that CD4(+) T cells express neogenin, a receptor for RGMa. Binding of RGMa to CD4(+) T cells led to activation of the small GTPase Rap1 and increased adhesion of T cells to intracellular adhesion molecule-1 (ICAM-1). Neutralizing antibodies to RGMa attenuated clinical symptoms of mouse myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) and reduced invasion of inflammatory cells into the CNS. Silencing of RGMa in MOG-pulsed BMDCs reduced their capacity to induce EAE following adoptive transfer to naive C57BL/6 mice. CD4(+) T cells isolated from mice treated with an RGMa-specific antibody showed diminished proliferative responses and reduced interferon-γ (IFN-γ), interleukin-2 (IL-2), IL-4 and IL-17 secretion. Incubation of PBMCs from patients with multiple sclerosis with an RGMa-specific antibody reduced proliferative responses and pro-inflammatory cytokine expression. These results demonstrate that an RGMa-specific antibody suppresses T cell responses, and suggest that RGMa could be a promising molecular target for the treatment of multiple sclerosis.
  Nature medicine 03/2011; 17(4):488-94. · 27.14 Impact Factor