Minoru Tahara

Tohoku University, Sendai-shi, Miyagi-ken, Japan

Are you Minoru Tahara?

Claim your profile

Publications (7)52.94 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The exceptional immunostimulatory capacity of DCs makes them potential targets for investigation of cancer immunotherapeutics. We show here in mice that TNF-alpha-stimulated DC maturation was accompanied by increased expression of OX40 ligand (OX40L), the lack of which resulted in an inability of mature DCs to generate cellular antitumor immunity. Furthermore, intratumoral administration of DCs modified to express OX40L suppressed tumor growth through the generation of tumor-specific cytolytic T cell responses, which were mediated by CD4+ T cells and NKT cells. In the tumors treated with OX40L-expressing DCs, the NKT cell population significantly increased and exhibited a substantial level of IFN-gamma production essential for antitumor immunity. Additional studies evaluating NKT cell activation status, in terms of IFN-gamma production and CD69 expression, indicated that NKT cell activation by DCs presenting alpha-galactosylceramide in the context of CD1d was potentiated by OX40 expression on NKT cells. These results show a critical role for OX40L on DCs, via binding to OX40 on NKT cells and CD4+ T cells, in the induction of antitumor immunity in tumor-bearing mice.
    Journal of Clinical Investigation 12/2007; 117(11):3330-8. · 12.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We examined therapeutic gene transfer of human hepatocyte growth factor (hHGF) to alveolar septa in mouse bleomycin-induced lung fibrosis using macroaggregated albumin-polyethylenimine complex (MAA-PEI). Intravenous administration of MAA-PEI along with 1 microg pCAG.hHGF to C57BL/6 mice increased the uptake of plasmids into alveolar capillary endothelial cells and epithelial cells, prolonged hHGF expression in the lung, and induced a level of hHGF expression equal to that seen with 10 microg of hHGF-expression plasmids alone. The exogenous source of hHGF gene expression increased the endogenous mouse HGF in the lungs and significantly decreased TNF-alpha, IL-6, and collagen synthesis after bleomycin injury. Because GFP-labeled bone marrow-derived stem cells after bleomycin injury were reduced in number by HGF, the primary mechanism of HGF is likely to be the prevention of apoptosis, as has been suggested by in vitro experiments. This novel HGF gene transfer method to alveolar septa with nonstimulatory MAA-PEI conjugates may have promising clinical applications.
    Molecular Therapy 08/2005; 12(1):58-67. · 7.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Associated Molecule with SH3 domain of STAM (AMSH) plays a critical role in the cytokine-mediated intracellular signal transduction downstream of the Jak2/Jak3-STAM complex. We newly identified a family molecule of AMSH, AMSH-FP (AMSH-Family Protein) in the mouse brain. AMSH-FP encodes the intracellular protein and has a highly conserved JAB1 Subdomain Homologous (JSH) region, suggesting that AMSH-FP may act as adaptor of gene transcription and/or regulation system. AMSH-FP has two splicing forms, one is expressed in various tissues, whereas the other one is restricted to expression in testis. We named the abundant type AMSH-FPalpha and the testis type AMSH-FPbeta. AMSH-FPbeta is a variant lacking N-terminal 166 amino acid residues of AMSH-FPalpha. Analysis of the 5(')-untranslated regions in AMSH-FPalpha and AMSH-FPbeta mRNAs and exon-intron structure of AMSH-FP gene suggests that testis-specific transcripts are generated due to alternative promoter usage and/or alternative splicing. Importantly, AMSH-FPbeta mRNA was not detected in juvenile and infertile mouse testis but was restrictively expressed in the haploid stage of testicular germ cells in the normal mature testis. We suggested that AMSH-FPbeta had a functional role in the spermiogenesis.
    Biochemical and Biophysical Research Communications 10/2003; 309(1):135-42. · 2.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 60-year-old woman was suffering from acute onset and progressive respiratory distress. Her radiographic findings showed bilateral volume loss in her lower lobes and consolidation predominantly distributed in peribronchovascular areas. The biopsied specimens performed by video-assisted thoracoscopic surgery revealed prominent fibromyxoid connective tissue within the terminal respiratory bronchioles and the alveolar spaces along the airways without marked interstitial fibrosis. No relevant cause was determined, and she was diagnosed as having idiopathic BOOP. Although her clinical course was fulminant with a poor reaction to steroid therapy, simultaneous administration of cyclosporin A and corticosteroid elicited a rapid improvement. This case report presents the effectiveness of cyclosporin A in the treatment of progressive BOOP.
    Internal Medicine 02/2002; 41(1):26-9. · 0.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To elucidate the role of microsomal triglyceride transfer protein (MTP) in the pathogenesis of alcoholic fatty liver, the effects of ethanol on MTP activity and gene expression were investigated. Male Sprague-Dawley rats fed an ethanol-containing liquid diet for 37 days, respectively, showed 2.9- and 4.9-fold increases in hepatic cholesterol and triglyceride content in comparison with rats fed an isocaloric ethanol-free diet (P<0.01). Furthermore, a significant decrease in MTP activity and mRNA expression (by 27 and 58%, respectively) was observed after ethanol administration. Intravenous injection of human recombinant hepatocyte growth factor (hrHGF) on each of the last 7 days markedly suppressed ethanol-induced lipid accumulation in the liver. This inhibition of fatty change by hrHGF was accompanied by recovery of MTP activity and gene expression. No inhibitory effect of hrHGF on ethanol-induced acyl-CoA synthetase activation was observed. Experiments using human hepatoma-derived HepG2 cells indicated a direct positive effect of hrHGF on MTP gene expression as well as apolipoprotein B secretion. These results suggest that reduced MTP activity is crucial to development of alcoholic fatty liver, while promotion of MTP activity by HGF might serve as a therapeutic measure against alcoholic liver steatosis.
    Journal of Hepatology 02/2002; 36(2):157-62. · 9.86 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatocyte growth factor (HGF) affects tumor growth/invasion and tumor neovascularization. A proposed HGF antagonist, NK4 (an amino-terminal kringle-domain peptide of HGF), inhibits tumor growth/invasion through the competition of HGF binding to its receptor, c-Met, and acts as an angiogenesis inhibitor. To investigate the in vivo effect of NK4 gene transfer, we constructed an adenovirus vector expressing human NK4 (AdCMV.NK4). Human lung cancer cell lines (A549 and H358) infected in vitro with AdCMV.NK4 yielded NK4 protein without a change in the cell growth rate. In contrast, direct injection of AdCMV.NK4 (1 x 10(9) pfu, twice) into established subcutaneous tumors in BALB/c nu/nu mice resulted in suppression of the tumors by 64% for A549 or by 91% for H358 compared with controls (P<0.02 or P<0.01, respectively). Counting of the tumor vessels revealed suppressed vascularity by 57% in H358 tumors when using AdCMV.NK4 (P<0.0001). Furthermore, systemic NK4 delivery by intraperitoneal injection of AdCMV.NK4 effectively suppressed both angiogenesis in the Matrigel assay (86% reduction, P<0.032), subcutaneous tumor growth in vivo (by 65% for H358, P<0.001), and hematogenous lung metastases without obvious side effects. These results indicate that NK4 elicits tumor-growth suppression in vivo through its anti-angiogenic activity and anti-HGF activity and that NK4 gene transfer can be an effective tool in the treatment of cancer.
    Molecular Therapy 02/2002; 5(2):177-85. · 7.04 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A fatty liver is characterized by the hyperaccumulation of lipids within hepatocytes and is often caused by excessive alcohol intake. Rats fed ethanol-containing diets for 37 days showed remarkable increase in hepatic lipids and lipid droplet accumulation in the hepatocytes, indicating the onset of alcoholic fatty liver. Administration of hepatocyte growth factor (HGF) for the last seven days of ethanol treatment markedly decreased hepatic lipids to a level lower than that seen before HGF treatment. In contrast, serum levels of lipids and lipoproteins increased with HGF administration. Primary cultured hepatocytes prepared from the fatty liver retained lipid droplets during a 48-hour culture. However, when cultured in the presence of HGF, intracellular lipid concentrations decreased and lipid secretion was enhanced. Consistent with these events, HGF stimulated the rate of protein synthesis of apolipoprotein B (apoB) and enhanced subsequent mobilization of lipids into the medium. These results indicate that HGF administration induced recovery from the fatty liver, at least in part, by enhancing apoB synthesis and the subsequent mobilization of lipids from hepatocytes with fatty change. The possibility that HGF can be therapeutic for subjects with an alcohol-related fatty liver warrants further attention.
    Journal of Clinical Investigation 03/1999; 103(3):313-20. · 12.81 Impact Factor