Kozo Motonaga

National Center of Neurology and Psychiatry, Кодаиры, Tōkyō, Japan

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Publications (6)28.72 Total impact

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    ABSTRACT: The gene encoding the beta-site amyloid precursor protein cleaving enzyme 2 (BACE2) has been determined to be located on the long arm of chromosome 21 at 21q22.3. BACE2 cleaves the amyloid precursor protein at the beta-secretase site and is thought to contribute to amyloid beta protein production. In the present study, changes in the expression of BACE2 were investigated immunohistochemically in the frontal cortex of patients with Down syndrome (DS). The immunoreactivity for BACE2 was detected in neurofibrillary tangle-bearing neurons from the elderly DS brains with Alzheimer-type neuropathology, but were not detected in those of DS brains without Alzheimer-type neuropathology or of control brains of any age. This suggests the possibility that the elevated expression of BACE2 is involved in the Alzheimer-type neuropathology of DS.
    Neuroscience Letters 07/2002; 326(1):64-6. · 2.03 Impact Factor
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    ABSTRACT: Werner's syndrome (WS) is an uncommon autosomal recessive disease resulting from mutational inactivation of human WRN helicase, Werner's syndrome protein (WRNp). Patients with WS progressively develop a variety of aging characteristics after puberty. The aim of this study was to determine the distribution of WRNp and the expression of the transcription factors regulating WRN gene expression in a variety of human organs in an attempt to understand the WS phenotype. Tissue specimens were obtained from 16 controls aged from 27 gestational weeks to 70 years of age and a 56 year old female patient with WS. The distribution of WRNp and the expression of the transcription factors regulating WRN gene expression-SP1, AP2, and retinoblastoma protein (Rb)- were studied in the various human organs by immunohistochemical and immunoblot analyses. In the healthy controls after puberty, high expression of WRNp was detected in seminiferous epithelial cells and Leydig cells in the testis, glandular acini in the pancreas, and the zona fasciculata and zona reticularis in the adrenal cortex. In addition, the SP1 and AP2 transcription factors, which regulate WRNp gene expression, appeared in an age dependent manner in those regions where WRNp was expressed. In controls after puberty, SP1 was expressed in the testis and adrenal gland, whereas AP2 was expressed in the pancreas. These findings suggest that the age specific onset of WS may be related to age dependent expression of WRNp in specific organs.
    Journal of Clinical Pathology 04/2002; 55(3):195-9. · 2.44 Impact Factor
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    ABSTRACT: Bloom syndrome (BS) involves the clinical features of telangiectatic erythema, immunodeficiency, and an increased risk for cancer. In order to clarify the pathogenetic significance of the responsible gene, BLM, which encodes a protein possessing homology to Escherichia coli RecQ helicase, the immunohistochemistry of BLM was examined in human brains and visceral organs from fetuses to adults and an adult with BS, using anti-BLM antibodies. Purkinje cells exhibited positive BLM immunoreactivity from 21 gestational weeks (GW), which transiently increased at approximately 40 GW. Neurons of the pontine tegmentum were immunolabeled from the early fetal period. In visceral organs, positive BLM immunoreactivity was observed in the Hassal corpuscles in the thymus from 24 GW, in beta-cells in the Langerhans islets of the pancreas from 36 GW, and in sperm cells and sperms of the testes from 11 years of age. But in a patient with BS, it was negative in the pancreas and testis tissues examined. The characteristic effect of BLM on specific cells in different periods suggests that the BLM gene product is closely related to neuronal development as well as immune, insulin secretory and sperm functions, which appear in different periods, and disorders of which are major symptoms of BS.
    Neuropathology 07/2001; 21(2):123-8. · 1.91 Impact Factor
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    ABSTRACT: We studied the expression of the apoptosis-related protein, E2F-1, in Down’s syndrome (DS) brains. The immunoreactivity for E2F-1 was detected in the pyramidal neurons of the cerebral cortex from DS brains exhibiting the neuropathological features of dementia of Alzheimer type (DAT), in accordance with the amyloid β protein (Aβ) deposition in the neuron. Therefore, the implication is that Aβ deposition may trigger E2F-1-mediated neuronal apoptosis in DS brains with DAT.
    Brain Research 07/2001; · 2.88 Impact Factor
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    ABSTRACT: We studied the expression of Down's syndrome cell adhesion molecule (DSCAM) in Down's syndrome (DS) and control brains, using antisera against peptide fragments of DSCAM. On Western blots of human, mouse and rat brain homogenates, the antisera recognized a product at approximately 200 kDa. In the brain of a 2-year-old patient with DS, Western blotting revealed an overexpression of DSCAM compared to an age-matched control. Immunohistochemistry demonstrated DSCAM in the cerebral and cerebellar white matter of both control and DS subjects, in accordance with the temporal and spatial sequence of myelination. In DS brains, immunoreactivity for DSCAM, compared to that for controls, was enhanced in the Purkinje cells at all ages, and in the cortical neurons during adulthood. In demented DS patients, DSCAM immunoreactivity was observed in the core and periphery of senile plaques. The pattern of DSCAM expression suggests that it may play a role as an adhesion molecule regulating myelination. The overexpression of DSCAM may also play a role in the mental retardation and the precocious dementia of DS patients, although the mechanism of neuronal dysfunction is undetermined.
    Acta Neuropathologica 01/2001; 100(6):654-64. · 9.73 Impact Factor
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    ABSTRACT: To investigate the pathophysiologic role of myotonic dystrophy protein kinase (DMPK) in the brain in myotonic dystrophy (MD), the developmental characteristics of DMPK immunoreactivity in the central nervous system and its alteration with disease were studied. Eleven patients' brain with MD (5 congenital form, 6 adult form) were examined by immunohistochemistry using a specific antibody against synthetic DMPK peptides, antipeptide DM1, and compared with 30 control brains, including 16 age-matched controls. In controls, DM1-immunoreactive neurons appeared in the early fetal frontal cortex and cerebellar granule cell layer, persisting through 29 weeks of gestation and then disappearing. In contrast, immunoreactive neurons continued to persist in the cerebral cortex and cerebellar granule cell layer of MD patients. When we counted DM1-immunoreactive neurons, the increase over controls was greater in the congenital form of MD than in the adult form, and was greater in the cerebrum than in the cerebellum in both forms of MD. DM1 immunostaining was predominantly nuclear, mirroring Western blotting of subcellular fractions. Differences in DM1 expression related to development and to the two forms of MD may be closely related to the pathogenesis of mental retardation in this disease.
    Acta Neuropathologica 12/2000; 100(5):513-20. · 9.73 Impact Factor

Publication Stats

73 Citations
28.72 Total Impact Points

Institutions

  • 2000–2002
    • National Center of Neurology and Psychiatry
      • Department of Mental Retardation and Birth Defect Research
      Кодаиры, Tōkyō, Japan
  • 2001
    • The University of Tokyo
      • Department of Animal Resource Sciences
      Tokyo, Tokyo-to, Japan