C Wada

Publications (8)19.42 Total impact

• Article: Time course of polyglutamine aggregate body formation and cell death: enhanced growth in nucleus and an interval for cell death.

  I Toyoshima, M Sugawara, K Kato, C Wada, T Shimohata, R Koide, O Onodera, S Tsuji
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  ABSTRACT: Polyglutamine (polyQ) aggregate bodies are a hallmark of dentatorubral-pallidoluysian atrophy and related neurodegenerative disorders, although the relationship between aggregate body formation and cell death is not clear. We analyzed the kinetics of polyQ aggregate formation and the time intervals for cell death, tracking individual cells using fluorescence video microscopy, for the first time. Expanded polyQ tracts of atrophin-1 with or without nuclear localization signal (NLS) labeled with green fluorescent protein (GFP) were constructed, Q57NLS/GFP and Q56/GFP, respectively. All of the Q57NLS/GFP aggregate bodies were in nuclei, and all of the Q56/GFP aggregate bodies were in cytoplasm. Aggregates of Q56/GFP were larger than those of Q57NLS/GFP. Surprisingly, a kinetic analysis showed that the latter grew 5.37 times faster than the former. The time interval between transfection and cell death was shorter in Q57NLS/GFP, but the time between the end of the rapid growing phase of aggregation and the start of the cell death process did not show a significant difference. Aggregate growth was confirmed to correspond to the accumulated free polyQ by the time of starting aggregation. These findings suggest that aggregate body formation induced by expanded polyQ stretches is a self-limiting process and is enhanced by factor(s) in nuclei, whereas it is not tightly bound to the cell death process.
  Journal of Neuroscience Research 06/2002; 68(4):442-8. · 2.74 Impact Factor
• Article: A novel de novo mutation in the desmin gene causes desmin myopathy with toxic aggregates.

  M Sugawara, K Kato, M Komatsu, C Wada, K Kawamura, P S Shindo, P N Yoshioka, K Tanaka, S Watanabe, I Toyoshima
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  ABSTRACT: To determine the cause and pathogenic mechanisms of a 21-year-old patient's cardioskeletal myopathy. The patient's muscle atrophy and weakness began in distal parts of limbs; cardiac and facial muscles were later involved. Desmin myopathy is a skeletal myopathy often associated with cardiomyopathy, caused by mutations in the desmin gene and characterized by desmin accumulation in affected muscle fibers, a leading marker of myofibrillar myopathies. Two kinds of deletions and seven missense mutations in the desmin gene have been identified. Clinical examination, electron microscopy of muscle tissue, two-dimensional gel electrophoresis, DNA sequencing, restriction enzyme analysis, and gene transfection were performed. Electron microscopy showed disruption of sarcomeres at Z discs and electron-dense aggregates in biopsied skeletal and heart muscle. Two-dimensional gel electrophoresis of the patient's skeletal muscle proteins showed massive accumulation of desmin. The authors identified a novel desmin mutation, L385P in one allele in the carboxyl end of the rod domain 2B in the patient's leukocytes and skeletal muscle; neither parent had the mutation. Serologic study and DNA markers confirmed the de novo mutation. A peptide harboring desmin rod domains 2A and 2B with L385P tagged with green fluorescent protein induced cytoplasmic aggregates, nuclear DNA condensation, and cell death. A novel de novo mutation, L385P, causes desmin myopathy. An expression study indicated the toxic effect of the L385P mutation.
  Neurology 11/2000; 55(7):986-90. · 8.31 Impact Factor
• Article: Massive accumulation of M and H subunits of neurofilament proteins in spinal motor neurons of neurofilament deficient Japanese quail, Quv.

  I Toyoshima, K Kato, M Sugawara, C Wada, S Okawa, M Kobayashi, O Masamune, S Watanabe
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  ABSTRACT: Quiver (Quv) is a non-sense mutation of neurofilament protein L subunit (NF-L) that causes neurofilament deficiency with preserved microtubules in Japanese quail. Anti-NF-M and anti-NF-H mAbs stained cell bodies of motor neurons in Quv embryo spinal cords much more intense than those in control spinal cords. Volume of motor neurons in Quv spinal cords increased to 2.3 times of control motor neurons. Immunoblot of Quv spinal cords revealed a relative increase in non- and hypo-phosphorylated NF-M and NF-H, and a decrease in the total amount of NFs. Quv sciatic nerves showed faintly reacted phosphorylated NF-M and NF-H. These results suggest that deficiency of assembled neurofilament results in decreased axonal transport of NFs and accumulation of NFs in cell bodies of spinal motor neurons.
  Neuroscience Letters 07/2000; 287(3):175-8. · 2.11 Impact Factor
• Article: Pontine atrophy in spinocerebellar ataxia type 6.

  M Sugawara, I Toyoshima, C Wada, K Kato, K Ishikawa, K Hirota, H Ishiguro, H Kagaya, Y Hirata, T Imota, M Ogasawara, O Masamune
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  ABSTRACT: To investigate the clinical range of spinocerebellar ataxia type 6 (SCA6), we screened CAG repeat expansion in the voltage-dependent alpha 1A calcium channel gene (CACNL1A4) in 71 ataxic patients in 60 families; 54 patients in 43 families with hereditary ataxia and 17 sporadic patients. Thirteen patients with SCA6 were detected to have elongated CAG in CACNL1A4. Of these, 7 patients had been diagnosed as having hereditary cerebellar cortical atrophy, and 6 patients had been found to have sporadic occurrence. One patient showed distinct pontine atrophy with prominent horizontal or oblique gaze nystagmus which is an unusual feature in sporadic olivopontocerebellar atrophy. For the efficient screening of SCA6, we would propose testing CAG repeat expansion in CACNL1A4, in patients with one of two markers: (1) horizontal or oblique gaze nystagmus without other eye movement disorders, (2) pure cerebellar atrophy, even if occurrence is sporadic. We should note that the pontine atrophy could also be caused by CAG repeat expansion in CACNL1A4.
  European Neurology 02/2000; 43(1):17-22. · 1.81 Impact Factor
• Article: [Hereditary ataxias in Akita prefecture].

  M Sugawara, I Toyoshima, K Kato, C Wada, T Imota, K Hirota, H Ishiguro, H Kagaya, A Hirata, M Ogasawara, O Masamune
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  ABSTRACT: To provide a genetic survey of hereditary ataxia, we performed PCR screening of SCA1, SCA2, MJD1 (SCA 3), SCA6, DRPLA, with 71 patients in 61 families living in Akita prefecture (1,205,571 population in 1997) in Japan. Of 71 patients in 61 families, 18 MJD1, 14 SCA6, 5 DRPLA, 1 SCA1 and 1 SCA2 patients were detected. Eighty percent of autosomal dominant inherited spinocerebellar degeneration (AD-SCD) including 7 spoladic patients genetically diagnosed as AD-SCD was MJD1 (45.7%) and SCA6 (34.3%). These suggest the prevalence rate of hereditary ataxias in Akita prefecture; 1.5 and 1.2/100,000 of MJD1 and SCA6, respectively. Only one patient of SCA1 was detected, which was frequently reported in Hokkaido and Tohoku area in Japan.
  Rinsho shinkeigaku = Clinical neurology 08/1999; 39(7):763-6.
• Article: [Muscle atrophy in isolated ACTH deficiency].

  C Wada, T Imota, K Kato, M Sugawara, I Toyoshima, O Masamune
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  ABSTRACT: We analyzed muscle area in CT and muscle pathology in a patient with isolated ACTH deficiency who started with the difficulty of elevation of both arms. Cortisol treatment resulted in full recovery from severe muscle atrophy and contracture of major joints. Change of volume of major muscles in arm, thigh and calf was followed. Major muscles were identified in CT and the area of each muscle was calculated with computer assistance. The increase of total muscle area in sequential 3 times in CT was up to 74% after prednisolone treatment. This indicates that the deficiency of cortisol resulted in 42% reduction of muscle volume. This also suggests that reduction of muscle volume induces the limitation of range of motion of shoulder joint. ATPase of muscle biopsy revealed the influence on fiber type proportion; type 1 : type 2A : type 2B = 29.6 : 6.0 : 64.4% and 35.7 : 17.6 : 46.7% in pre-treatment and post-treatment of cortisol, respectively. Mean diameters of muscle fibers in type 1, type 2A and type 2B was 41.8, 41.8, 39.1 microns and 46.2, 44.0, 37.2 microns in pre-treatment and post-treatment of cortisol, respectively. These suggest that deficiency of glucocorticoid introduces the reduction of the activity of the motor neurons innervating type 1 and type 2A muscle fibers.
  Nō to shinkei = Brain and nerve 10/1998; 50(9):841-8.
• Article: Kinesin and cytoplasmic dynein in spinal spheroids with motor neuron disease.

  I Toyoshima, M Sugawara, K Kato, C Wada, K Hirota, K Hasegawa, H Kowa, M P Sheetz, O Masamune
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  ABSTRACT: Kinesin and cytoplasmic dynein are two major molecular motors responsible for fast axonal transport. As visualized by immunohistochemistry with monoclonal antibodies, both motors were found to be distributed throughout the cell bodies, dendrites and axons of motor neurons in normal human spinal cords. Large axonal swellings, spheroids, in the spinal cords of patients with motor neuron disease showed massive accumulation of kinesin co-localized with highly phosphorylated neurofilaments. Of 114 spheroids in five spinal cords, 87% were stained heavily with the three anti-kinesin antibodies used in this study. Cytoplasmic dynein was scarce or absent in most of the spheroids. These findings suggest that kinesin selectively accumulates in the spheroids of motor neuron axons, causing disturbance of the machinery for anterograde fast axonal transport in motor neuron disease.
  Journal of the Neurological Sciences 08/1998; 159(1):38-44. · 2.35 Impact Factor
• Article: Kinesin accumulation in chick spinal axonal swellings with beta,beta'-iminodipropionitrile (IDPN) intoxication.

  I Toyoshima, K Kato, M Sugawara, C Wada, O Masamune
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  ABSTRACT: Kinesin is a major molecular motor responsible for anterograde axonal transport. Chicks were injected with beta,beta'-iminodipropionitrile (IDPN) to induce axonal swellings in spinal motor neurons and spinal sensory ganglion neurons. Cylindrical swollen axons were found in the anterior horn and anterior funiculus of the spinal cord, anterior root, and spinal ganglia. All of the axonal swellings were heavily stained with two anti-kinesin monoclonal antibodies. The swellings were mildly stained with an anti-cytoplasmic dynein and anti-tubulin antibodies, and weakly stained with an anti-tau antibody. These suggest the isolated disturbance of kinesin transport with neurofilament accumulation in IDPN intoxication.
  Neuroscience Letters 07/1998; 249(2-3):103-6. · 2.11 Impact Factor