Alzheimer Disease: Imagawa M

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.

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.

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.

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.

Itoh N, Arai H, Urakami K, Ishiguro K, Ohno H, Hampel H, Buerger K, Wiltfang J, Otto M, Kretzschmar H, Moeller HJ, Imagawa M, Kohno H, Nakashima K, Kuzuhara S, Sasaki H, Imahori K. · Department of Neurology, Mie University School of Medicine, Tsu, Japan. · Ann Neurol. · Pubmed #11506396 No free full text.

Abstract: We surveyed a total of 570 cerebrospinal fluid (CSF) samples from a variety of diseases, including Alzheimer's disease (AD; n = 236), non-AD-demented and nondemented diseases (n = 239), and normal controls (n = 95) to quantitate levels of tau protein phosphorylated at serine 199 (CSF/phospho-tau199) by a recently established sandwich ELISA. The CSF/phospho-tau199 levels in the AD group were significantly elevated compared to those in all the other non-AD groups. Receiver operating characteristics curves showed that the diagnostic sensitivity and specificity for the AD group vs all the other non-AD groups using the CSF/phospho-tau199 were 85.2% and 85.0%, respectively. Furthermore, there was a significant positive correlation between CSF/phospho-tau199 and CSF/total-tau levels in the AD group. Elevated CSF/phospho-tau199 in the AD group was noted irrespective of age, gender, dementia severity, and number of apolipoprotein E4 alleles. Thus, we suggest that CSF/phospho-tau199 may be a novel and logical biomarker in supporting antemortem diagnosis of AD.

Hatanaka Y, Kamino K, Fukuo K, Mitsuda N, Nishiwaki-Ueda Y, Sato N, Satoh T, Yamamoto H, Yoneda H, Imagawa M, Miki T, Ohta S, Ogihara T. · Department of Geriatric Medicine, Osaka University Medical School, Suita, Japan. · Clin Genet. · Pubmed #11076057 No free full text.

Abstract: Low density lipoprotein (LDL) receptor-related protein (LRP) gene polymorphisms located in the 5' region and in exon 3, and the apolipoprotein E (APOE) genotype were determined in 100 Japanese patients affected by late-onset Alzheimer's disease (AD). We matched 246 controls for age and found no association between the polymorphism located in the 5' region of the LRP gene. The distribution of LRP exon 3 genotypes and alleles did not differ between AD and the control groups. However, the frequency of T allele in the Alzheimer's group having APOE-epsilon4 was lower than that in the control group having APOE-epsilon4, but it was only marginally significant (p = 0.022). Age of onset was significantly younger in the patients with CC genotype than those carrying the T allele (p = 0.03), and this trend was more evident among non-APOE-epsilon4 carriers (p = 0.008). These results support the possibility that ApoE and LRP may contribute to the development of AD.

Kamino K, Nagasaka K, Imagawa M, Yamamoto H, Yoneda H, Ueki A, Kitamura S, Namekata K, Miki T, Ohta S. · Department of Biochemistry and Cell Biology, Nippon Medical School, Kawasaki, Kanagawa, 211-8533, Japan. · Biochem Biophys Res Commun. · Pubmed #10873585 No free full text.

Abstract: Mitochondrial aldehyde dehydrogenase 2 (ALDH2) deficiency is caused by a mutant allele in the Mongoloids. To examine whether genetic constitutions affecting aldehyde metabolism influence the risk for late-onset Alzheimer's disease (LOAD), we performed a case-control study in the Japanese population on the deficiency in ALDH2 caused by the dominant-negative mutant allele of the ALDH2 gene (ALDH2*2). In a comparison of 447 patients with sex, age, and region matched nondemented controls, the genotype frequency carrying the ALDH2*2 allele was significantly higher in the patients than in the controls (48.1% vs 37.4%, P = 0.001). Logistic regression analysis indicates that carriage of the ALDH2*2 allele is an independent risk for LOAD of the epsilon4 allele of the apolipoprotein E gene (APOE-epsilon4) (P = 0.002). Moreover, the odds ratio for LOAD in carriers of the ALDH2*2 allele was almost twice that in noncarriers, irrespective of status with regard to the APOE-epsilon4 allele. Among patients homozygous for the APOE-epsilon4 allele, age at onset of LOAD was significantly lower in those with than without the ALDH2*2 allele. In addition, dosage of the ALDH2*2 allele significantly affected age at onset of patients homozygous for the APOE-epsilon4 allele. These results indicate that the ALDH2 deficiency is a risk for LOAD, synergistically acting with the APOE-epsilon4 allele.

Imafuku I, Masaki T, Waragai M, Takeuchi S, Kawabata M, Hirai S, Ohno S, Nee LE, Lippa CF, Kanazawa I, Imagawa M, Okazawa H. · Department of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan. · J Cell Biol. · Pubmed #10508860 links to  free full text

Abstract: Presenilin 1 (PS1) is the causative gene for an autosomal dominant familial Alzheimer's disease (AD) mapped to chromosome 14. Here we show that QM/Jun-interacting factor (Jif)-1, a negative regulator of c-Jun, is a candidate to mediate the function of PS1 in the cell. We screened for proteins that bind to PS1 from a human embryonic brain cDNA library using the two-hybrid method and isolated one clone encoding the QM/Jif-1 gene. The binding of QM/Jif-1 to full-length PS1 was confirmed in vitro by pull-down assay, and in vivo by immunoprecipitation assays with human samples, including AD brains. Immunoelectronmicroscopic analysis showed that QM/Jif-1 and PS1 are colocalized at the endoplasmic reticulum, and the nuclear matrix in human brain neurons. Chloramphenicol acetyltransferase assays in F9 cells showed that PS1 suppresses transactivation by c-Jun/c-Jun but not by c-Jun/c-Fos heterodimers, consistent with the reported function of QM/Jif-1. By monitoring fluorescent recombinant protein and by gel mobility shift assays, PS1 was shown to accelerate the translocation of QM from the cytoplasm to the nucleus and to thereby suppress the binding of c-Jun homodimer to 12-O-tetradecanoylphorbol-13- acetate (TPA)-responsive element (TRE). PS1 suppressed c-jun-associated apoptosis by retinoic acid in F9 embryonic carcinoma cells, whereas this suppression of apoptosis is attenuated by mutation in PS1. Collectively, the novel function of PS1 via QM/Jif-1 influences c-jun-mediated transcription and apoptosis.