Search PubMed⌕ Search

Biomedical subjects

Toshihiro Tanaka

Publications and source records attributed to Toshihiro Tanaka.

At least 19 recordsLinked to original sources
PubMed2007

Gene transfer of the CD40-ligand to human dendritic cells induces NK-mediated antitumor effects against human carcinoma cells.

The CD40-ligand (CD40L) is a key molecule for the activation of dendritic cells (DCs), followed by the induction of DC maturation and cytokine production. Here we found that DC infected with adenovirus vector encoding human CD40L (CD40L-DC) displayed significantly higher levels of immune accessory molecules and IL-12 production than did uninfected cells, and that CD40L-DC produced much higher levels of IFN-gamma. To investigate whether CD40L-DC-derived these soluble factors could stimulate NK cells without physical cell-to-cell contact, we cocultured NK cells with CD40L-DC in transwell culture plates. NK cells showed up-regulated cytotoxic activity toward various squamous oral cell carcinoma (OSC-70, HSC-2, HSC-3), and we determined that both IL-12 and IFN-gamma contributed to the CD40L-DC-mediated NK cell activation. NK cells stimulated with CD40L-DC resulted in the induction of the cell surface expression of TRAIL, the production of IFN-gamma and intracellular accumulation of granzyme B. The cytotoxic activity of NK cells stimulated with CD40L-DC could be mostly inhibited by neutralizing antibody for TRAIL and completely abrogated by the combination of antibody and exocytosis inhibitor, indicating that this was mainly mediated by a TRAIL-TRAIL-receptor interaction and granule exocytosis. Moreover, CD40L-DC-activated NK cells could induce up-regulation of a death-receptor TRAIL-R2 (DR5) and down-regulation of a decoy receptor TRAIL-R3 (DcR1) on carcinoma cells. Overall, these results have revealed that CD40L-DC could activate an innate immune reaction by stimulating NK cells followed by carcinoma cells, supporting that administration of CD40L-DC may have potential as an anticancer therapy.

Adenoviridae↗
PubMed2007

A functional SNP in ITIH3 is associated with susceptibility to myocardial infarction.

Myocardial infarction (MI) results from complex interactions of multiple genetic and environmental factors. To disclose genetic backgrounds of MI, we performed a large-scale, case-control association study using 52,608 gene-based single-nucleotide polymorphism (SNP) markers, and identified a candidate SNP located on chromosome 3p21.2-p21.1. Subsequent linkage-disequilibrium mapping indicated very significant association between MI and a SNP in exon 2 of the inter-alpha (globulin) inhibitor 3 gene (ITIH3; chi(2) = 24.88, P = 6.1 x 10(-7), 3,353 affected individuals versus 3,807 controls). In vitro functional analyses showed that this SNP enhanced the transcriptional level of the ITIH3 gene. Furthermore, we found expression of the ITIH3 protein in the vascular smooth muscle cells and macrophages in the human atherosclerotic lesions, suggesting ITIH3 SNP to be a novel genetic risk factor of MI.

Alpha-Globulins↗
PubMed2006

Linkage disequilibrium of evolutionarily conserved regions in the human genome.

BACKGROUND: The strong linkage disequilibrium (LD) recently found in genic or exonic regions of the human genome demonstrated that LD can be increased by evolutionary mechanisms that select for functionally important loci. This suggests that LD might be stronger in regions conserved among species than in non-conserved regions, since regions exposed to natural selection tend to be conserved. To assess this hypothesis, we used genome-wide polymorphism data from the HapMap project and investigated LD within DNA sequences conserved between the human and mouse genomes. RESULTS: Unexpectedly, we observed that LD was significantly weaker in conserved regions than in non-conserved regions. To investigate why, we examined sequence features that may distort the relationship between LD and conserved regions. We found that interspersed repeats, and not other sequence features, were associated with the weak LD tendency in conserved regions. To appropriately understand the relationship between LD and conserved regions, we removed the effect of repetitive elements and found that the high degree of sequence conservation was strongly associated with strong LD in coding regions but not with that in non-coding regions. CONCLUSION: Our work demonstrates that the degree of sequence conservation does not simply increase LD as predicted by the hypothesis. Rather, it implies that purifying selection changes the polymorphic patterns of coding sequences but has little influence on the patterns of functional units such as regulatory elements present in non-coding regions, since the former are generally restricted by the constraint of maintaining a functional protein product across multiple exons while the latter may exist more as individually isolated units.

Biological Evolution↗
PubMed2006

Identification of a novel non-coding RNA, MIAT, that confers risk of myocardial infarction.

Through a large-scale case-control association study using 52,608 haplotype-based single nucleotide polymorphism (SNP) markers, we identified a susceptible locus for myocardial infarction (MI) on chromosome 22q12.1. Following linkage disequilibrium (LD) mapping, haplotype analyses revealed that six SNPs in this locus, all of which were in complete LD, showed markedly significant association with MI (chi2=25.27, P=0.0000005; comparison of allele frequency, 3,435 affected individuals versus 3,774 controls, in the case of intron 1 5,338 C>T; rs2331291). Within this locus, we isolated a complete cDNA of a novel gene, designated myocardial infarction associated transcript (MIAT). MIAT has five exons, and in vitro translation assay showed that MIAT did not encode any translational product, indicating that this is likely to be a functional RNA. In vitro functional analyses revealed that the minor variant of one SNP in exon 5 increased transcriptional level of the novel gene. Moreover, unidentified nuclear protein(s) bound more intensely to risk allele than non-risk allele. These results indicate that the altered expression of MIAT by the SNP may play some role in the pathogenesis of MI.

Alleles↗
PubMed2006

A functional SNP in PSMA6 confers risk of myocardial infarction in the Japanese population.

Inflammation is now considered critical in the pathogenesis of myocardial infarction. One of the mechanisms regulating the inflammatory process is the ubiquitin-proteasome system. We investigated whether variants of the 20S proteasome are associated with susceptibility to myocardial infarction and found a common SNP (minor allele frequency of 0.35) in the proteasome subunit alpha type 6 gene (PSMA6) conferring risk of myocardial infarction in the Japanese population (chi(2) = 21.1, P = 0.0000044, 2,592 affected individuals versus 2,851 controls). We replicated this association in another panel of myocardial infarction and control subjects, although its relevance to other ethnic groups remains to be clarified. The SNP, located in the 5' untranslated region of exon 1 in this gene, enhanced the transcription of PSMA6. Moreover, suppression of PSMA6 expression using short interfering RNA in cultured cells reduced activation of the transcription factor NF-kappaB by stabilizing phosphorylated IkappaB. Our results implicate this PSMA6 SNP as a previously unknown genetic risk factor for myocardial infarction.

Alleles↗
PubMed2006

Carcinoembryonic antigen-targeted selective gene therapy for gastric cancer through FZ33 fiber-modified adenovirus vectors.

PURPOSE: A major problem when using the adenoviral vectors for gene therapy applications is thought to be related to low transduction efficiency in cancer cells or to side effects in normal cells. There is an urgent requirement to improve the specificity of gene delivery in the context of cancer gene therapy. EXPERIMENTAL DESIGN: We constructed a genetically modified adenovirus incorporating an IgG Fc-binding motif from the Staphylococcus protein A, Z33, within the HI loop (Adv-FZ33). A remarkable degree of targeted gene delivery to gastric cancer cells was obtained with Adv-FZ33 with the fully human anti-carcinoembryonic antigen (CEA) monoclonal antibody, C2-45. RESULTS: In vitro LacZ or EGFP gene expression after Adv-FZ33 infection via C2-45 was 20 times higher than control monoclonal antibody in MKN-45 at 1,000 viral particles/cell. We generated Ax3CAUP-FZ33 (UP-FZ33), which is an Adv-FZ33 derivative vector expressing a therapeutic gene (i.e., Escherichia coli uracil phosphoribosyltransferase), which converts 5-fluorouracil (5-FU) directly to 5-fluoro-UMP. UP-FZ33 with C2-45 enhanced the cytotoxicity of 5-FU by 10.5-fold in terms of IC(50) against MKN-45 compared with control IgG4. In a nude mouse peritoneal dissemination model, tumor growth in mice treated with UP-FZ33/C2-45/5-FU was significantly suppressed, and tumor volumes were less than one-fourth of those of the control IgG4 group (P < 0.05). The median survival time of the UP-FZ33/C2-45/5-FU group was significantly longer than those treated with PBS or 5-FU only (P < 0.01). CONCLUSIONS: These data suggest that CEA-targeted FZ33 mutant adenovirus-mediated gene delivery offers a strong and selective therapeutic modality against CEA-producing cancers.

Adenoviridae↗
PubMed2006

Inflammation as a risk factor for myocardial infarction.

Myocardial infarction (MI) is one of the common diseases whose pathogenesis includes genetic factors. To reveal genetic backgrounds of this clinically heterogeneous disorder, we started our case-control association study by examining large-scale gene-based single nucleotide polymorphism (SNP) sets for approximately 1,000 patients and controls. As a core genotyping method, a combination of multiplex PCR and Invader method was used, and after genotyping approximately 65,000 SNPs, we found two SNPs located within lymphotoxin-alpha (LTA) gene showing significant association with MI. LTA is one of the cytokines produced in the early stages of vascular inflammatory processes. These SNPs seem to be involved in inflammation by both qualitatively and quantitatively modifying the function of LTA protein, thereby conferring a risk of MI. The genetic association was further confirmed by other researchers using white European trios. To further understand the roles of LTA protein in the pathogenesis of MI, we searched for proteins that interact directly with LTA protein and identified galectin-2 protein as a binding partner of LTA protein. It is a member of galactose-binding lectin family whose function has not been well characterized. Genetic association study again revealed that an SNP in LGALS2 encoding galectin-2 was also associated with susceptibility to MI. This genetic substitution seemed to affect the transcriptional level of galectin-2, which led to altered secretion of LTA, thereby affecting the degree of inflammation. Thus, our findings indicate the importance of inflammation, especially the LTA cascade, in the pathogenesis of MI. Also, combined strategy of genetic and molecular-cellular biological approaches may be useful for clarification of the pathogenesis of common diseases in general.

Case-Control Studies↗
PubMed2006

Genome-wide association study to identify single-nucleotide polymorphisms conferring risk of myocardial infarction.

Myocardial infarction (MI) is characterized by abrupt occlusion of coronary artery resulting in irreversible damage to cardiac muscle. This disease might result from the interactions of multiple genetic and environmental factors, none of which can cause disease solely by themselves. To reveal the genetic bases of MI, we performed a large-scale, case-control association study using 92,788 gene-based single-nucleotide polymorphism (SNP) markers. We have identified functional SNPs within the lymphotoxin-alpha gene located on chromosome 6p21 conferred susceptibility to MI. This chapter describes a detailed protocol for performing a genome-wide association study as used in our MI study.

Case-Control Studies↗
PubMed2006

Subungual glomus tumor diagnosis based on imaging.

A 50-year-old woman had had tenderness of the nail bed of the right thumb for more than 20 years. For the previous 5 or 6 years, she had also had attacks of pain with exposure to cold, and deformity of the right thumb nail plate began to appear. There was red discoloration on the proximal aspect of the nail bed, and a longitudinal fissure on the distal aspect of the nail plate. Ultrasonography showed a well-circumscribed hypoechoic area under the proximal aspect of the nail plate and the nail matrix. Color Doppler ultrasonography showed subtle flow signals within the hypoechoic area. Magnetic resonance imaging showed a well-circumscribed mass in the same place that the ultrasonography indicated. It was isointense to the dermis of the nail bed on the T1-weighted image and hyperintense on the T2-weighted image. Radiography showed subtle dorsal bone erosion in the distal phalanx. Surgery was performed. Histologically, the diagnosis of a subungual glomus tumor was made. We diagnosed the exact location and size of the subungual glomus tumor by preoperative imaging and completely removed it easily and safely. Imaging is very useful for diagnosing tumors of the nail unit.

Female↗
PubMed2005

Genome sequencing and analysis of Aspergillus oryzae.

The genome of Aspergillus oryzae, a fungus important for the production of traditional fermented foods and beverages in Japan, has been sequenced. The ability to secrete large amounts of proteins and the development of a transformation system have facilitated the use of A. oryzae in modern biotechnology. Although both A. oryzae and Aspergillus flavus belong to the section Flavi of the subgenus Circumdati of Aspergillus, A. oryzae, unlike A. flavus, does not produce aflatoxin, and its long history of use in the food industry has proved its safety. Here we show that the 37-megabase (Mb) genome of A. oryzae contains 12,074 genes and is expanded by 7-9 Mb in comparison with the genomes of Aspergillus nidulans and Aspergillus fumigatus. Comparison of the three aspergilli species revealed the presence of syntenic blocks and A. oryzae-specific blocks (lacking synteny with A. nidulans and A. fumigatus) in a mosaic manner throughout the genome of A. oryzae. The blocks of A. oryzae-specific sequence are enriched for genes involved in metabolism, particularly those for the synthesis of secondary metabolites. Specific expansion of genes for secretory hydrolytic enzymes, amino acid metabolism and amino acid/sugar uptake transporters supports the idea that A. oryzae is an ideal microorganism for fermentation.

Aspartic Acid Endopeptidases↗
PubMed2005

Sequencing of Aspergillus nidulans and comparative analysis with A. fumigatus and A. oryzae.

The aspergilli comprise a diverse group of filamentous fungi spanning over 200 million years of evolution. Here we report the genome sequence of the model organism Aspergillus nidulans, and a comparative study with Aspergillus fumigatus, a serious human pathogen, and Aspergillus oryzae, used in the production of sake, miso and soy sauce. Our analysis of genome structure provided a quantitative evaluation of forces driving long-term eukaryotic genome evolution. It also led to an experimentally validated model of mating-type locus evolution, suggesting the potential for sexual reproduction in A. fumigatus and A. oryzae. Our analysis of sequence conservation revealed over 5,000 non-coding regions actively conserved across all three species. Within these regions, we identified potential functional elements including a previously uncharacterized TPP riboswitch and motifs suggesting regulation in filamentous fungi by Puf family genes. We further obtained comparative and experimental evidence indicating widespread translational regulation by upstream open reading frames. These results enhance our understanding of these widely studied fungi as well as provide new insight into eukaryotic genome evolution and gene regulation.

Aspergillus fumigatus↗
PubMed2005

COL6A1, the candidate gene for ossification of the posterior longitudinal ligament, is associated with diffuse idiopathic skeletal hyperostosis in Japanese.

STUDY DESIGN: Genetic screening of collagen 6A1 gene (COL6A1) in patients with diffuse idiopathic skeletal hyperostosis (DISH) recruited in Japan and the Czech Republic. OBJECTIVE: To investigate allelic associations between DISH and nucleotide variants of COL6A1. SUMMARY OF BACKGROUND DATA: DISH is a skeletal hyperostotic disease characterized by ligamentous ossification of the anterolateral side of the spine. Ossification of the posterior longitudinal ligament (OPLL) is a related disorder with DISH, and COL6A1 was identified as a susceptibility gene to OPLL. COL6A1 was examined for susceptibility in DISH patients from Japan and the Czech Republic. METHODS: Seven single nucleotide polymorphisms of COL6A1 were genotyped by direct sequencing. The allele frequencies were compared between 97 Japanese DISH patients and 298 Japanese controls, and between 96 Czech DISH patients and 96 Czech controls by chi2 test. RESULTS: The intron 32 (-29) single nucleotide polymorphisms of COL6A1 was significantly associated with the Japanese DISH patients (chi2 = 9.33; P = 0.0022), but not with the Czech DISH patients. CONCLUSIONS: Because COL6A1 could be a susceptibility to the occurrence of DISH and OPLL in the Japanese population, we consider that COL6A1 could be responsible for the hyperostotic state, leading to ectopic bone formation in the spinal ligament.

Aged↗
PubMed2005

Impact of atherosclerosis-related gene polymorphisms on mortality and recurrent events after myocardial infarction.

Although previous epidemiologic studies have suggested an association between the onset of myocardial infarction (MI) and some genetic variations, the impact of these variants on recurrent cardiovascular events after MI has not been fully elucidated. We genotyped 87 polymorphisms of 73 atherosclerosis-related genes in consecutive acute MI patients registered in the Osaka Acute Coronary Insufficiency Study and compared the incidence of death and major adverse cardiac events (MACE) among the polymorphisms of each gene. After initial screening in 507 patients, we selected nine polymorphisms for screening in all 1586 patients. Multivariate Cox regression analysis revealed that G allele carriers at the position 252 of the lymphotoxin alpha (LTA) gene were independently associated with an increased risk of death (hazard ratio [HR]: 2.46; 95% CI: 1.24-4.86). In conclusion, a 252G allele of LTA is associated with an increased risk of death after AMI and may be a useful genetic predictor.

Atherosclerosis↗
PubMed2005

Bcl-xL gene transfer inhibits Bax translocation and prolongs cardiac cold preservation time in rats.

BACKGROUND: Apoptosis is an important cause of early graft loss after heart transplantation. Bcl-xL was reported to protect the heart against normothermic ischemia and reperfusion injury. In this study, we determined whether overexpression of Bcl-xL could inhibit tissue injury resulting from prolonged cold preservation followed by warm reperfusion of heart transplants. METHODS AND RESULTS: Lewis rat hearts were transduced with an adenovirus vector harboring Bcl-xL cDNA (AxCAhBclxL) 4 days before collection of tissue. After preservation in University of Wisconsin solution at 4 degrees C for 24 hours, the heart was either perfused with a Langendorff device ex vivo or used for heterotopic heart transplantation in vivo. Bcl-xL gene transfer significantly reduced the infarct size (23.0+/-2.6% versus 47.7+/-7.0% in saline control and 48.6+/-6.1% in vector control, P<0.01) after 2-hour reperfusion at 37 degrees C with the Langendorff device and significantly decreased creatine kinase release (0.82+/-0.27 IU, versus 1.57+/-0.33 and 1.50+/-0.37 IU in saline and vector controls, respectively; P<0.05). In heart transplantation, overexpression of Bcl-xL inhibited Bax translocation from the cytosol to the mitochondria, resulting in decreased cytochrome c release from the mitochondria; it also significantly decreased cardiac cell apoptosis and improved graft survival rate after long cold preservation, followed by warm reperfusion. CONCLUSIONS: Bcl-xL gene transfer inhibited the translocation of Bax and prolonged the cold preservation time of cardiac transplants. This may be a potential therapeutic method in clinical practice.

Animals↗
PubMed2005

Combined effect of 25-hydroxycholesterol and IL-1beta on IL-8 production in human colon carcinoma cell line (Caco-2).

Interleukin-1 beta (IL-1beta) is an important mediator in intestinal inflammation. IL-1beta promotes IL-8 production, which can be modulated by a number of factors, including oxidative stress. Interestingly, oxysterols, which are thought to contribute to inflammation in atherosclerotic plaques, are also produced by intestinal epithelial cells. Thus, we investigated the effect of oxysterols, including 25-hydroxycholesterol and 7beta-hydroxycholesterol, on IL-1beta-induced IL-8 production in Caco-2 cells (a human colon carcinoma cell line). Pre-treatment of Caco-2 cells with 25-hydroxycholesterol significantly enhanced IL-1beta-induced IL-8 expression at both mRNA and protein levels. However, 7beta-hydroxycholesterol showed very little effect on IL-8 production. Furthermore, pre-treatment with 25-hydroxycholesterol, followed by IL-1beta stimulation, enhanced IL-8 promoter activity beyond that observed with IL-1beta alone. These results suggest that 25-hydroxycholesterol enhances IL-1beta-induced IL-8 production, possibly by enhancing promoter activity.

Adenocarcinoma↗
PubMed2005

Clomipramine-induced hypersensitivity syndrome with unusual clinical features.

Drug-induced hypersensitivity syndrome is a severe drug eruption with fatal visceral organ failures associated with human herpesvirus-6 (HHV-6) reactivation. We present a case of clomipramine-induced hypersensitivity syndrome, which displayed in succession two different reactions akin to those described for Gianotti-Crosti syndrome and infectious mononucleosis. HHV-6 reactivation was confirmed serologically after the latter reaction, suggesting that our case may have represented a biphasic reaction to HHV-6 reactivation.

Adult↗