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Biomedical subjects

Yusuke Nakamura

Publications and source records attributed to Yusuke Nakamura.

230 records · Page 13Linked to original sources
PubMed2002

Nucleotide pyrophosphatase gene polymorphism associated with ossification of the posterior longitudinal ligament of the spine.

Ossification of the posterior longitudinal ligament (OPLL) of the spine is a disease that causes paralysis by compressing the spinal cord. Based on the fact that the nucleotide pyrophosphatase (Npps) gene is responsible for ectopic ossification in ttw, an OPLL model mouse, the possibility was explored whether the human NPPS gene is associated with susceptibility to and severity of OPLL. First, we screened for single-nucleotide polymorphisms (SNPs) in the human NPPS locus using selected 25 OPLL patients with young onset (< 35 years old) or severe ossification (> 10 ossified vertebrae), and identified three novel SNPs in the locus. A case-control association study between 180 OPLL patients and 265 non-OPLL controls showed that one of these SNPs, IVS15-14T --> C substitution, was more frequently observed in OPLL patients (p = 0.022), especially in those with severe ossification (p < 0.0001) and young onset (p = 0.002), than in controls. A stratified study with the number of ossified vertebrae in OPLL patients revealed that IVS15-14T --> C substitution (p = 0.013) as well as young onset (p = 0.046) and female sex (p = 0.006) were associated with severe ossification. We conclude that the IVS15-14T --> C substitution in the human NPPS gene is associated not only with susceptibility to, but also with severity of OPLL.

Adult↗
PubMed2002

Isolation and characterization of a novel human gene, VANGL1, as a therapeutic target for hepatocellular carcinoma.

Through analysis of genome-wide expression profiles, we have been attempting to isolate novel molecular targets for diagnosis, treatment and prevention of hepatocellular carcinoma (HCC). Among the genes that a cDNA microarray showed to be commonly transactivated in HCCs, we identified a novel human homologue of the Drosophila Van Gogh/Strabismus gene and termed it VANGL1 [Vang (Van Gogh, Drosophila)-like 1]. This gene, which encoded a transcript with an open reading frame of 1,572 bp, was expressed specifically in testis and ovary among 16 adult normal tissues examined. Transfection of antisense S-oligonucleotides, but not of sense S-oligonucleotides, into hepatoma cells suppressed expression of VANGL1 and subsequent growth of these cells was inhibited to a marked degree. The findings suggest that VANGL1 might serve as a diagnostic marker for HCC as well as a potential molecular target for development of novel therapeutic drugs.

3T3 Cells↗
PubMed2002

Maturational sequence of neuroblastoma revealed by molecular analysis on cDNA microarrays.

Neuroblastoma (NB), one of the most common solid tumors among children, is histologically classified by the degree of maturation. To elucidate the mechanisms underlying its maturational sequence, we analyzed gene-expression profiles of 14 NB tumors on cDNA microarrays consisting of 23,040 genes. Computational analysis identified 78 genes whose expression levels were significantly different between differentiating NB tumors and poorly differentiated NB tumors. This group included genes associated with cell maturation and apoptosis. Among them we identified 15 that were up-regulated in Stage IV NB tumors; these included genes encoding cell adhesion molecules and cytoskeleton proteins. The set of genes we report here should contribute to a better understanding of NB tumor maturation and could lead to development of new therapeutic strategies.

Apoptosis↗
PubMed2002

[SNP collection, pharmacogenomics, and the future of drug therapy].

Common genetic variations may, in large part, explain genetic predispositions to common diseases and individual differences in pharmacological responsiveness. Single-nucleotide polymorphisms (SNPs) are the most frequent type of genetic variation, and are thought to be present every several-hundred bases, on average, throughout the human genome. SNPs can provide medically important information through (1) their contribution to high-density maps for studies of susceptibility to common diseases; (2) provision of genetic data for personalized medical service; and (3) identification of genes associated with the efficacy and side-effect of drugs. We have been focusing on genomic loci that encode various enzymes and transporters involved in the metabolism of drugs, and have described more than 5,500 SNP and other variations. Our collection of human variations should prove useful for investigations designed to detect associations between genetic variations and common diseases or responsiveness to drug therapy. In this review we introduce the recent progress and future direction of human genome analysis and its impact on medicine.

ATP Binding Cassette Transporter 1↗
PubMed2002

Isolation and characterization of the mouse ortholog of the Fukuyama-type congenital muscular dystrophy gene.

Fukuyama-type congenital muscular dystrophy (FCMD) is a severe autosomal-recessive muscular dystrophy accompanied by brain malformation. Previously, we identified the gene responsible for FCMD through positional cloning. Here we report the isolation of its murine ortholog, Fcmd. The predicted amino acid sequence of murine fukutin protein encoded by Fcmd is 90% identical to that of its human counterpart. Radiation hybrid mapping localized the gene to 2.02 cR telomeric to D4Mit272 on chromosome 4. Northern blot analysis revealed ubiquitous expression of Fcmd in adult mouse tissues. Through in situ hybridization, we observed a wide distribution of Fcmd expression throughout embryonic development, most predominantly in the central and peripheral nervous systems. We also detected high Fcmd expression in the ventricular zone of proliferating neurons at 13.5 days post-coitum. Brain malformation in FCMD patients is thought to result from defective neuronal migration. Our data suggest that neuronally expressed Fcmd is likely to be important in the development of normal brain structure.

Alternative Splicing↗
PubMed2002

Prediction of chemosensitivity for patients with acute myeloid leukemia, according to expression levels of 28 genes selected by genome-wide complementary DNA microarray analysis.

To identify genes involved in the sensitivity of acute myeloid leukemia (AML) cells to chemotherapy, we monitored gene-expression profiles of cancer cells from 76 AML patients using a cDNA microarray consisting of 23,040 genes. We identified 63 genes that were commonly overexpressed and 372 genes suppressed in AML. Because these genes represent key molecules for disclosing the molecular mechanisms of AML, they may be potential targets for drug development. We also found 28 that revealed different expression levels between good and poor responders to chemotherapy and appeared to be associated with chemosensitivity. On that basis, we developed a "Drug Response Scoring" system that was correlated well with individual sensitivity to an anticancer drug regimen. Among the 44 cases with positive drug-response scores by our definition, 40 achieved complete remission after treatment, whereas the only 3 of the 20 cases with negative scores responded well to the treatment. An ability to predict chemosensitivity should eventually lead to achievement of our goal of "personalized therapy."

Adult↗
PubMed2001

The p53 family member genes are involved in the Notch signal pathway.

The p53 tumor suppressor is a transcription factor that regulates cell growth and death in response to environmental stimuli such as DNA damage. p63/p51 and p73 were recently identified as members of the p53 gene family. In contrast to p53 however, p63 and p73 are rarely mutated in human cancers. Mice that lack p53 are developmentally normal, while p63 and p73 appear to play critical roles in normal development. To determine how p63 and p73 are involved in normal development, we attempted to identify target genes that are specifically regulated by p63 and/or p73 but not by p53. We found that the Jagged1 (JAG1) and Jagged2 (JAG2) genes, encoding ligands for the Notch receptors, are up-regulated by p63 and p73. Furthermore, we identified a p63-binding site in the second intron of the JAG1 gene, which can directly interact with the p63 protein in vivo, as assessed by a chromatin immunoprecipitation assay. A heterologous reporter assay revealed that this p63-binding site is a functional response element and is specific for p63. We also found a target of Notch signaling, HES-1 was up-regulated in Jurkat cells, in which Notch1 is highly expressed, when co-cultured with p63-transfected cells, suggesting that p63 can trigger the Notch signal pathway in neighboring cells. Our findings show an association between the p53 family genes and Notch signaling and suggest a potential molecular mechanism for the involvement of the p53 family genes in normal development.

Calcium-Binding Proteins↗
PubMed2001

Combined hepatocellular/cholangiocellular carcinoma with sarcomatoid features: genetic analysis for histogenesis.

The histogenesis of sarcomatoid transformation in hepatocellular carcinomas (HCCs) and cholangiocellular carcinomas (CCCs) remains unclear. In the current case, microsatellite loss of heterozygosity (LOH) assay and mutational analysis of the p53 gene with immunohistochemical examination were performed to investigate the histogenesis of each component. The tumor was composed of two parts: one part comprised poorly differentiated HCC (HCC portion), while the other part included undifferentiated, sarcomatoid HCC and CCC (combined portion). LOH at D8S555 was detected in both portions. 1-bp cytosine was deleted at codon 241 of exon 7 of the p53 gene in the combined portion. Immunohistochemically, p53 accumulated in the nuclei of undifferentiated, sarcomatoid HCC and CCC cells, suggesting that the p53 gene mutation might be common in these components. These results support the hypothesis that undifferentiated, sarcomatoid HCC and CCC could be offspring from the original HCC.

Journal Article↗
PubMedDate not supplied

Identification of semaphorin3B as a direct target of p53.

A cDNA microarray analysis indicated that Semaphorin3B (Sema3B), a gene whose product is involved in axon guidance and axonal repulsion, is inducible by p53. Introduction of exogenous p53 into a glioblastoma cell line lacking wild-type p53 (U373MG) dramatically induced expression of Sema3B mRNA. An electrophoretic mobility shift assay and a reporter assay confirmed that a potential p53 binding site present in the promoter region had p53-dependent transcriptional activity. Expression of endogenous Sema3B was induced in response to genotoxic stresses caused by adriamycin treatment or UV irradiation in a p53-dependent manner. Ectopic expression of Sema3B in p53-defective cells reduced the number of colonies in colony formation assays. These results suggest that Sema3B might play some role in regulating cell growth as a mediator of p53 tumor-suppressor activity.

Base Sequence↗
PubMedDate not supplied

Cyclin K as a direct transcriptional target of the p53 tumor suppressor.

Cyclin K, a newly recognized member of the "transcription" cyclin family, may play a dual role by regulating CDK and transcription. Using cDNA microarray technology, we found that cyclin K mRNA was dramatically increased in U373MG, a glioblastoma cell line deficient in wild-type p53, in the presence of exogenous p53. An electrophoretic mobility-shift assay showed that a potential p53-binding site (p53BS) in intron 1 of the cyclin K gene could indeed bind to p53 protein. Moreover, a heterologous reporter assay revealed that the p53BS possessed p53-dependent transcriptional activity. Colony-formation assays indicated that overexpression of cyclin K suppressed growth of T98G, U373MG and SW480 cells. The results suggested that cyclin K may play a role in regulating the cell cycle or apoptosis after being targeted for transcription by p53.

Adenoviridae↗
PubMedDate not supplied

Classification of sensitivity or resistance of cervical cancers to ionizing radiation according to expression profiles of 62 genes selected by cDNA microarray analysis.

To identify a set of genes related to radiosensitivity of cervical squamous cell carcinomas and to establish a predictive method, we compared expression profiles of 9 radiosensitive and 10 radioresistant tumors obtained by biopsy before treatment, on a cDNA microarray consisting of 23,040 human genes. We identified 121 genes whose expression was significantly greater in radiosensitive cells than in radioresistant cells, and 50 genes that showed higher levels of expression in radioresistant cells than in radiosensitive cells. Some of these genes had already known to be associated with the radiation response, such as aldehyde dehydrogenase 1 (ALDH1) and X-ray repair cross-complementing 5 (XRCC5) (P<.05, Mann-Whitney test). The validity of the total of 171 genes as radiosensitivity related genes were certified by permutation test (P<.05). Furthermore, we selected 62 genes on the basis of a clustering analysis, and confirmed the validity of these genes with cross-validation test. The cross-validation test also indicates the possibility of making prediction of radiosensitivity for discriminating radiation-sensitive from radiation resistant biopsy samples by predicting score (PS) values calculated from expression values of 62 genes in 19 samples, because the prediction successfully and unequivocally discriminated the radiosensitive phenotype from the radioresistant phenotype in our test panel of 19 cervical carcinomas. The extensive list of genes identified in these experiments provides a large body of potentially valuable information for studying the mechanism(s) of radiosensitivity, and selected 62 genes opens the possibility of providing appropriate and effective radiotherapy to cancer patients.

Aged↗
PubMedDate not supplied

A < 1.7 cM interval is responsible for Dmo1 obesity phenotypes in OLETF rats.

1. Dmo1 (Diabetes Mellitus OLETF type I) is a major quantitative trait locus for dyslipidaemia, obesity and diabetes phenotypes of male Otsuka Long Evans Tokushima Fatty (OLETF) rats. 2. Our congenic lines, produced by transferring Dmo1 chromosomal segments from the non-diabetic Brown Norway (BN) rat into the OLETF strain, have confirmed the strong, wide-range therapeutic effects of Dmo1 on dyslipidaemia, obesity and diabetes in the fourth (BC4) and fifth (BC5) generations of congenic animals. Analysis of a relatively small number of BC5 rats (n = 71) suggested that the critical Dmo1 interval lies within a < 4.9 cM region between D1Rat461 and D1Rat459. 3. To confirm the assignment of the Dmo1 critical interval, we intercrossed BC5 animals to produce a larger study population (BC5:F1 males; n = 406). For the present study, we used bodyweight at 18 weeks of age as an index of obesity; this phenotype is representative of the closely associated dyslipidaemia and hyperglycaemia phenotypes. 4. Interval mapping assigned logarithm of odds (LOD) peaks at the D1Rat90 marker (LOD = 9.11). One LOD support interval lies within the < 1.7 cM region between D1Rat461 and D1Rat459. 5. This large intercross study confirms that Dmo1 is likely localized within the interval.

Animals↗
PubMedDate not supplied

Mutated G-protein-coupled receptor GPR10 is responsible for the hyperphagia/dyslipidaemia/obesity locus of Dmo1 in the OLETF rat.

1. We have confirmed the Diabetes Mellitus OLETF type I (Dmo1) effect on hyperphagia, dyslipidaemia and obesity in the Otsuka Long-Evans Tokushima Fatty (OLETF) strain. The critical interval was narrowed down to 570 kb between D1Got258 to p162CA1 by segregation analyses using congenic lines. 2. Within the critical 570 kb region of the Dmo1 locus, we identified the G-protein-coupled receptor gene GPR10 as the causative gene mutated in the OLETF strain. The ATG translation initiation codon of GPR10 is changed into ATA in this strain and, so, is unavailable for the initiation of translation. 3. The GPR10 protein has a cognate ligand, namely prolactin-releasing peptide (PrRP). Centrally administered PrRP suppressed the food intake of congenic rats that have a Brown Norway derived Dmo1 region (i.e. with wild-type GPR10), but did not suppress that of the OLETF strain, indicating that GPR10 is without function and could explain hyperphagia in the OLETF strain. 4. Moreover, when restricted in food volume to the same level consumed by the congenic strain, OLETF rats showed few differences in the parameters of dyslipidaemia and obesity compared with congenic strains. 5. Taken together, these results demonstrate that the mutated GPR10 receptor is responsible for the hyperphagia leading to obesity and dyslipidaemia in the obese diabetic strain rat.

Animals↗