Alzheimer Disease: Kuwano R

Shoji M, Kuwano R, Asada T, Imagawa M, Higuchi S, Urakami K, Arai H, Ihara Y, Anonymous00237, Anonymous00238. · Department of Neurology, Neuroscience, Biophysiological Science, Okayama University Graduate School of Medicine and Dentistry. · Rinsho Shinkeigaku. · Pubmed #15782613 No free full text.

Abstract: To clarify the risk and associated genes of Alzheimer's disease by genome-wide screening, a Japanese study group was organized in 2000 under Yasuo Ihara, Tokyo University, supported by a Grant-in-Aid for Science Research on Priority Areas (C) -Advanced Brain Science Project from Ministry of Education, Culture, Sports, Science and Technology, Japan. This is the first Japanese consortium study under permission of the ethical committees of the enrolled institutes based on the ethics guidelines for human genome/gene analysis research, Ministry of Education, Culture, Sports, Science and Technology Ministry of Health, Labor and Welfare Ministry of Economy, Trade and Industry. In this project, 2,000 genome samples from patients with Alzheimer's disease, 2,000 control subjects, and 200 siblings affected with Alzheimer's disease are collected and analyzed. For this purpose, it is necessary to analyze samples from accurately diagnosed Alzheimer patients and controls using standard criteria for diagnosis and neuropsychological evaluation, which have been confirmed by an evidence-based studying a Japanese population. Here, we propose criteria for the diagnosis and clinical assessment of Alzheimer's disease. This proposal consists of a definition of Alzheimer's disease based on recent advances in research, diagnostic criteria based on DSM-IV, NINCDS-ADRDA and ICD-10, exclusion criteria for other dementia disorders, routine and detailed tests for neuropsychological and laboratory evaluations, criteria for neuroimaging and biomarkers, definitive diagnostic criteria and classification of clinical subtypes.

Kuwano R, Takei N, Miyashita A. · Department of Molecular Genetics, Center for Bioresources, Brain Research Institute, Niigata University. · Nippon Rinsho. · Pubmed #19507496 No free full text.

Abstract: A goal of genetic research is to identify risk factor loci for complex disorders, and to understand a molecular mechanism of the factor on development of the disease. Dementia is the most common neurodegererative disorder in the elderly. Three frequent neurodegererative dementias are Alzheimer disease, dementia with Lewy bodies, and frontotemporal lobar degeneration, characterized by senile plaque with amyloid beta and neurofibrillary tangles with tau, Lewy body with alpha-synuclein, tau or tau-negative ubiquitin-immunoreactive neuronal inclusions with TDP-43, respectively. Overlapping symptoms, progress and neuropathological findings often complicate the diagnosis. Genetic risk factors obtained by genome-wide association study might provide new insight into etiology common to dementia.

Takei N, Miyashita A, Tsukie T, Arai H, Asada T, Imagawa M, Shoji M, Higuchi S, Urakami K, Kimura H, Kakita A, Takahashi H, Tsuji S, Kanazawa I, Ihara Y, Odani S, Kuwano R, Anonymous00084. · Department of Molecular Genetics, Bioresource Science Branch, Center for Bioresources, Brain Research Institute, Niigata University, Niigata 951-8585, Japan. · Genomics. · Pubmed #19442637 No free full text.

Abstract: The epsilon4 allele of APOE is a well-characterized genetic risk factor for late-onset Alzheimer disease (LOAD). Nevertheless, using high-density single nucleotide polymorphisms (SNPs), there have only been a few studies involving genetic association and linkage disequilibrium (LD) analyses of in and around the APOE. Here, we report fine mapping of a genomic region (about 200 kb) including the APOE in Japanese using 260 SNPs (mean intermaker distance, 0.77 kb). A case-control study demonstrated that 36 of these SNPs exhibited significance after adjustment for multiple testing. These SNPs are located in a genomic region including four genes, PVRL2, TOMM40, APOE and APOC1. Recombination rate estimation revealed that the associated region is firmly sandwiched between two recombination hotspots. Strong LD between these SNPs was observed (mean |D'|=0.914). These data suggest that the three genes other than APOE, i.e. PVRL2, TOMM40 and APOC1, could also yield a predisposition to LOAD.

Xu W, Kawarabayashi T, Matsubara E, Deguchi K, Murakami T, Harigaya Y, Ikeda M, Amari M, Kuwano R, Abe K, Shoji M. · Department of Neurology, Neuroscience, Biophysiological Science, Okayama University Graduate School of Medicine, Dentistry and Pharmacy, 2-5-1 Shikatacho, Okayama 700-8558, Japan. · Brain Res. · Pubmed #18534566 No free full text.

Abstract: Antibodies to amyloid beta protein (Abeta) are present naturally or after Abeta vaccine therapy in human plasma. To clarify their clinical role, we examined plasma samples from 113 patients with Alzheimer's disease (AD) and 205 normal controls using the tissue amyloid plaque immunoreactivity (TAPIR) assay. A high positive rate of TAPIR was revealed in AD (45.1%) and age-matched controls (41.2%), however, no significance was observed. No significant difference was observed in the MMS score or disease duration between TAPIR-positive and negative samples. TAPIR-positive plasma reacted with the Abeta40 monomer and dimer, and the Abeta42 monomer weakly, but not with the Abeta42 dimer. TAPIR was even detected in samples from young normal subjects and young Tg2576 transgenic mice. Although the Abeta40 level and Abeta40/42 ratio increased, and Abeta42 was significantly decreased in plasma from AD groups when compared to controls, no significant correlations were revealed between plasma Abeta levels and TAPIR grading. Thus an immune response to Abeta40 and immune tolerance to Abeta42 occurred naturally in humans without a close relationship to the Abeta burden in the brain. Clarification of the mechanism of the immune response to Abeta42 is necessary for realization of an immunotherapy for AD.

Tomiyama T, Nagata T, Shimada H, Teraoka R, Fukushima A, Kanemitsu H, Takuma H, Kuwano R, Imagawa M, Ataka S, Wada Y, Yoshioka E, Nishizaki T, Watanabe Y, Mori H. · Department of Neuroscience, Osaka City University Graduate School of Medicine, Osaka, Japan. · Ann Neurol. · Pubmed #18300294 No free full text.

Abstract: OBJECTIVE: Soluble oligomers of amyloid beta (Abeta), rather than amyloid fibrils, have been proposed to initiate synaptic and cognitive dysfunction in Alzheimer's disease (AD). However, there is no direct evidence in humans that this mechanism can cause AD. Here, we report a novel amyloid precursor protein (APP) mutation that may provide evidence to address this question. METHODS: A Japanese pedigree showing Alzheimer's-type dementia was examined for mutations in APP, PSEN1, and PSEN2. In addition, 5,310 Japanese people, including 2,121 patients with AD, were screened for the novel APP mutation. The pathogenic effects of this mutation on Abeta production, degradation, aggregation, and synaptotoxicity were also investigated. RESULTS: We identified a novel APP mutation (E693Delta) producing variant Abeta lacking gulutamate-22 (E22Delta) in Japanese pedigrees showing Alzheimer's-type dementia and AD. Although the secretion of total Abeta was markedly reduced by this mutation, the variant Abeta was more resistant to proteolytic degradation. The mutant peptides showed the unique aggregation property of enhanced oligomerization but no fibrillization, and inhibited hippocampal long-term potentiation more potently than wild-type peptide in rats in vivo. Consistent with the nonfibrillogenic property of the variant Abeta, a very low amyloid signal was observed in the patient's brain on positron emission tomography using Pittsburgh compound-B. INTERPRETATION: The E693Delta mutation has been suggested as a cause of dementia because of enhanced formation of synaptotoxic Abeta oligomers. Our findings may provide genetic validation in humans for the emerging hypothesis that the synaptic and cognitive impairment in AD is primarily caused by soluble Abeta oligomers.

Kuwano R. · Bioresource Science Branch Center for Bioresources Brain Research Institute, Niigata University. · Rinsho Shinkeigaku. · Pubmed #18210832 No free full text.

Abstract: The Japanese Genetic Study Consortium for Alzheimer's disease (JGSCAD) was organized in 2000 to discover strategies to delay onset and progression of dementia. To identify an additional gene (s) causing susceptibility to APOE-epsilon4 negative late-onset AD (LOAD), we performed single nucleotide polymorphisms (SNP)-based association analysis on chromosomes 10 with only the APOE-epsilon3*3 genotype. The significant associated SNPs, spanning 220 kb at genomic position 101 Mb, with LOAD and were located in the dynamin-binding protein (DNMBP) gene. Quantitative real-time RT-PCR analysis demonstrated that neuropathologically confirmed LOAD brains exhibit a significant reduction of DNMBP mRNA compared with age-matched ones. DNMBP was discovered as a scaffold protein that brings the dynamin and actin regulatory proteins together, and is concentrated at synapses. In view of the fact that synaptic dysfunction precedes Abeta deposition in the brains of AD patients, our observations raise the possibility that DNMBP, as one of risk factors, might play a predominant role in the early stage of LOAD lacking the APOE-epsilon4 allele. Novel genetic risk factors will be discovered through genome-wide association studies with high density of SNP markers.

Kaneko H, Kakita A, Kasuga K, Nozaki H, Ishikawa A, Miyashita A, Kuwano R, Ito G, Iwatsubo T, Takahashi H, Nishizawa M, Onodera O, Sisodia SS, Ikeuchi T. · Department of Molecular Neuroscience, Center for Bioresources, Niigata University, Niigata 951-8585, Japan. · J Neurosci. · Pubmed #18045903 links to  free full text

Abstract: Mutations in the PSEN1 gene encoding presenilin 1 (PS1) are linked to a vast majority of pedigrees with early-onset, autosomal dominant forms of familial Alzheimer's disease (FAD). Lewy body (LB) pathology is frequently found in the brains of FAD patients harboring PSEN1 mutations. We recently reported on a novel PS1 mutation with the deletion of threonine at codon 440 (deltaT440) in a familial case diagnosed as having the neocortical type of dementia with LBs (DLB) and variant AD. In this report, we investigated the possible involvement of PS1 deltaT440 mutation in aberrant alpha-synuclein accumulation. We established cell lines that stably express either wild-type (WT) PS1 or the FAD-linked PS1 H163R, E280A, deltaE9, and PS1 deltaT440 mutants and now demonstrate that the expression of the PS1 deltaT440 mutant led to a marked elevation in the ratio of beta-amyloid (Abeta) 42/40 peptides in a conditioned medium. More importantly, we report here that the levels of phosphorylated alpha-synuclein increase in neuronal and non-neuronal cells expressing the PS1 deltaT440 mutant compared with cells that express WT PS1 or the PS1 H163R and E280A variants that are not associated with LB pathology. This finding is consistent with our demonstration of elevated levels of phosphorylated alpha-synuclein in the detergent-resistant fraction prepared from a patient's brain with PS1 deltaT440 mutation. These observations raise the intriguing suggestion that the mechanism(s) by which the PS1 deltaT440 mutant causes DLB and variant AD are by enhancing the phosphorylation of alpha-synuclein and the ratio of Abeta(42/40) peptides, respectively, in the brain.

Miyashita A, Arai H, Asada T, Imagawa M, Matsubara E, Shoji M, Higuchi S, Urakami K, Kakita A, Takahashi H, Toyabe S, Akazawa K, Kanazawa I, Ihara Y, Kuwano R, Anonymous00354. · Center for Bioresources, Brain Research Institute, Niigata University, Niigata, Japan. · Hum Mol Genet. · Pubmed #17761686 links to  free full text

Abstract: Alzheimer's disease (AD), the most common form of dementia in the elderly, was found to exhibit a trend toward a higher risk in females than in males through epidemiological studies. Therefore, we hypothesized that gender-related genetic risks could exist. To reveal the ones for late-onset AD (LOAD), we extended our previous genetic work on chromosome 10q (genomic region, 60-107 Mb), and single nucleotide polymorphism (SNP)-based genetic association analyses were performed on the same chromosomal region, where the existence of genetic risk factors for plasma Abeta42 elevation in LOAD was implied on a linkage analysis. Two-step screening of 1140 SNPs was carried out using a total of 1408 subjects with the APOE-epsilon3*3 genotype: we first genotyped an exploratory sample set (LOAD, 363; control, 337), and then genotyped some associated SNPs in a validation sample set (LOAD, 336; control, 372). Seven SNPs, spanning about 38 kb, in intron 9 of CTNNA3 were found to show multiple-hit association with LOAD in females, and exhibited more significant association on Mantel-Haenszel test (allelic P-values(MH-F) = 0.000005945-0.0007658). Multiple logistic regression analysis of a total of 2762 subjects (LOAD, 1313; controls, 1449) demonstrated that one of the seven SNPs directly interacted with the female gender, but not with the male gender. Furthermore, we found that this SNP exhibited no interaction with the APOE-epsilon4 allele. Our data suggest that CTNNA3 may affect LOAD through a female-specific mechanism independent of the APOE-epsilon4 allele.

Kuwano R, Miyashita A, Arai H, Asada T, Imagawa M, Shoji M, Higuchi S, Urakami K, Kakita A, Takahashi H, Tsukie T, Toyabe S, Akazawa K, Kanazawa I, Ihara Y, Anonymous00173. · Genome Science Branch, Center for Bioresource-Based Researches, Brain Research Institute, Niigata University, Niigata, Japan. · Hum Mol Genet. · Pubmed #16740596 links to  free full text

Abstract: The apolipoprotein E (APOE) gene has been consistently shown to be a major genetic risk factor; however, all cases of Alzheimer's disease (AD) cannot be attributed to the epsilon4 variant of APOE, because about half of AD patients have the APOE-epsilon3*3 genotype. To identify an additional genetic risk factor(s), we performed large-scale single nucleotide polymorphism (SNP)-based association analysis of 1526 late-onset AD patients and 1666 control subjects in a Japanese population. We prepared two independent sets consisting of exploratory and validation samples, respectively, with only the APOE-epsilon3*3 genotype, and first carried out genotyping for the exploratory set with 1206 SNPs in the region between 60 and 107 Mb on chromosome 10q that is implicated by linkage studies as containing an AD susceptibility locus. Thirty-five SNPs that showed significant values (P<0.01) were followed-up to detect any association with the validation samples. Finally, six SNPs exhibited replicated significant associations (P=0.000035-0.00048) on meta-analysis of both sets. These SNPs were clustered in a locus spanning 220 kb at genomic position 101 Mb, and three of the six SNPs were located in the dynamin-binding protein (DNMBP) gene. Quantitative real-time RT-PCR analysis demonstrated that neuropathologically confirmed AD brains exhibit a significant reduction of DNMBP mRNA compared with age-matched ones (P<0.0169). Thus, we confirmed the association of DNMBP with AD individuals with the APOE-epsilon3*3 genotype or lacking the epsilon4 allele, and DNMBP may be one of the susceptibility genes for AD.

Ishikawa A, Piao YS, Miyashita A, Kuwano R, Onodera O, Ohtake H, Suzuki M, Nishizawa M, Takahashi H. · Department of Neurology, Nishi-Ojiya National Hospital, Ojiya, Japan. · Ann Neurol. · Pubmed #15732120 No free full text.

Abstract: We report early-onset parkinsonism and dementia of 18 years' duration in a 52-year-old man whose grandfather and father had suffered from a similar neurological disease. In this patient, we found neuronal loss in various brain regions including the substantia nigra and cerebral cortex, Lewy bodies, cotton wool plaques, corticospinal tract degeneration, cerebral amyloid angiopathy, and a novel three-base pair deletion in exon 12 of the presenilin-1 (PSEN1) gene. We considered that the mutant PSEN1 might play an important role in the pathogenetic process of both aggregation of alpha-synuclein into Lewy bodies and deposition of beta-amyloid into cotton wool plaques.