Publications by authors named "Keikichi Takahashi"

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by mutations in human NOTCH3. We have recently reported that mutant Notch3 shows a greater propensity to form aggregates, and these aggregates resist degradation, leading to accumulation in the endoplasmic reticulum (ER). In this study, we searched for low-molecular compounds that decrease the amount of mutant Notch3 aggregates.

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Mutations in the human NOTCH3 gene cause cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), but the pathogenic mechanisms of the disorder remain unclear. We investigated the cytotoxic properties of mutant Notch3 using stable cell lines with inducible expression of either wild-type or two mutants p.R133C and p.

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Human E-selectin, an endothelial adhesion molecule, is induced in the brain arteries by cerebral ischemia and participates in the infiltration of leukocytes that cause inflammatory reaction leading to brain damage. To prevent leukocyte infiltration in the brain, we designed gene therapeutic constructs to suppress E-selectin expression. The constructs were composed of microRNAs (miR-E1 and miR-E2) complementary to the human E-selectin cDNA, which were directed by a minimum cis-element of the human E-selectin promoter.

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Some lines of evidence have suggested that subcortical ischemic vascular dementia (SIVD) is a common form of vascular dementia (VaD), and that its pathological changes are the development of ischemic white matter (WM) lesions under chronic hypoperfusion and lacunes. Here, we have developed a novel mouse model of VaD with WM lesions, which was induced by right unilateral common carotid artery occlusion (rUCCAO). The mice subjected to rUCCAO exhibited chronic cerebral hypoperfusion in the cerebral hemisphere ipsilateral to rUCCAO monitored using a laser-Doppler flow meter (p<0.

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Presenilin 1 (PS1) forms the gamma-secretase complex with at least three components: nicastrin, APH-1, and PEN-2. This complex mediates intramembrane cleavage of amyloid precursor protein (APP) to generate beta-amyloid protein (Abeta) as well as other type 1 transmembrane proteins. Although PS1 mutations linked to familial Alzheimer's disease influence these cleavages, their biological consequences have not been fully understood.

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CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is an inherited disease characterized by recurrent subcortical ischemic strokes leading to pseudobulbar palsy, migraine attacks with aura, psychiatric disturbances and vascular dementia. The disease is caused by mutations in the Notch3 receptor. In the present study, we investigated the mechanisms underlying the pathological alterations in CADASIL.

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The case of a 72-year-old demented woman having episodes of strokes without any risk factors for cardiovascular disease is reported. Her elder brother and sister have also had stroke episodes since their middle age. She experienced hallucinations, delusions, and recurrent headaches since the age of 55.

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Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited systemic vascular disorder characterized by recurrent subcortical ischemic strokes leading to vascular dementia. The gold standard to confirm the diagnosis is to identify a mutation in the underlying gene NOTCH3, encoding a transmembrane receptor protein. Granular osmiophilic material (GOM) deposition around vascular smooth muscle cells is a specific diagnostic feature of CADASIL and electron microscopic examination of a skin biopsy is another useful method for its diagnosis.

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CADASIL is associated with mutations in the Notch3 gene but the causal mechanisms of the disorder remain unclear. We studied effects of widely established mutations on Notch3 receptor processing and ligand-mediated activation in stable lines of HEK293 and SH-SY5Y cells expressing either human wild-type or mutant Notch3 receptor. None of the four mutations (R90C, R133C, C185R and R449C) affected quantities of the full-length, amino-terminal or carboxyl-terminal fragments and did not impair intracellular trafficking in both cell types.

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The Notch3 gene, a member of the Notch gene family, is expressed in a wide variety of tissues during development. We generated and analyzed Notch3-deficient mice to assess the in vivo role of the Notch3 gene. Consistent with previous observation of Krebs et al.

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We report a 39-year-old woman who presented with only dizziness and vertigo for 2 months. Neurological examination revealed no abnormalities except for hypereflexia on the left side extremities. Neurootological examination revealed no abnormalities.

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A new oral vaccine for Alzheimer's disease was developed using recombinant adeno-associated virus vector carrying Abeta cDNA (AAV/Abeta). Oral administration of the vaccine without adjuvant induced the expression and secretion of Abeta1-43 or Abeta1-21 in the epithelial cell layer of the intestine in amyloid precursor protein transgenic mice. Serum antibody levels were elevated for more than six months, while T cell proliferative responses to Abeta was not detected.

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We have examined Notch3 mutations in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) whose samples were submitted to us in Japan. The subjects were composed of 21 Japanese, 1 Iranian, 1 Korean and 1 Canadian families. Mutations in the Notch3 gene were found in 7 of 24 families examined.

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Mutations in the microtubule-associated tau gene are responsible for frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). A reduced ability of the mutated microtubule-associated tau protein to interact with microtubules causes microtubule destabilization leading to deleterious effects on axonal transport and the formation of tau filaments. Here, we describe a new mutation of the tau gene, a T --> C transition at position +11 of the intron following exon 10 (T --> C 3'E10 +11) in the family showing frontotemporal dementia with very early age of onset (the first decade of proband's life).

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Frontotemporal dementia represents up to 10% of all dementias and is, next to Alzheimer's disease and Lewy body disease, the third most common cause of degenerative dementia. The term "frontotemporal dementia" covers a range of conditions, including Pick's disease, frontal lobe degeneration and dementia associated with motor neurone disease. Neuropathologically FTD is characterised by atrophy of the frontal and temporal lobes of the cerebral cortex, often with additional subcortical changes.

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