Biomedical subjects

Takuma Kato

Publications and source records attributed to Takuma Kato.

17 recordsLinked to original sources

PubMed2006

Noradrenalin-secreting retroperitoneal schwannoma resected by hand-assisted laparoscopic surgery: report of a case.

A 66-year-old woman was admitted to our hospital for investigation of a retroperitoneal mass. She was asymptomatic but her serum noradrenalin and vanillylmandellic acid levels were increased remarkably. Computed tomographic angiography showed a mass in the left side of the superior mesenteric artery (SMA) divergence, 6 x 4 cm in size, supplied mainly by the left adrenal artery. We performed hand-assisted laparoscopic surgery (HALS) using a Cavitron ultrasonic surgical aspirator. Abdominal exploration revealed that the tumor was located in the left side of the SMA root, but was not adhered to the adjacent organs. Her vital signs remained stable during the operation. Microscopic examination revealed a palisade formation, confirming a histopathological diagnosis of degenerated schwannoma (Antoni type B). Immunohistologically, the tumor cells were stained with S-100 protein and neuron-specific enolase. Her noradrenalin level normalized immediately after the operation and she remains in good health 3 years 2 months later.

Aged↗

PubMed2006

In vivo antigen delivery by a Salmonella typhimurium type III secretion system for therapeutic cancer vaccines.

Bacterial vectors may offer many advantages over other antigen delivery systems for cancer vaccines. We engineered a Salmonella typhimurium vaccine strain to deliver the NY-ESO-1 tumor antigen (S. typhimurium-NY-ESO-1) through a type III protein secretion system. The S. typhimurium-NY-ESO-1 construct elicited NY-ESO-1-specific CD8+ and CD4+ T cells from peripheral blood lymphocytes of cancer patients in vitro. Oral administration of S. typhimurium-NY-ESO-1 to mice resulted in the regression of established NY-ESO-1-expressing tumors. Intratumoral inoculation of S. typhimurium-NY-ESO-1 to NY-ESO-1-negative tumors resulted in delivery of antigen in vivo and led to tumor regression in the presence of preexisting NY-ESO-1-specific CD8+ T cells. Specific T cell responses against at least 2 unrelated tumor antigens not contained in the vaccine were observed, demonstrating epitope spreading. We propose that antigen delivery through the S. typhimurium type III secretion system is a promising novel strategy for cancer vaccine development.

Animals↗

PubMed2006

Endocrine disruptors that deplete glutathione levels in APC promote Th2 polarization in mice leading to the exacerbation of airway inflammation.

Endocrine-disrupting chemicals (EDC) are ubiquitous in environment and may have various undesirable effects on human health. In the present study, we have shown that some EDC [benzophenone, p-octylphenol, and tributyltin chloride (TBT)] promoted strong Th2 polarization via suppression and augmentation of Th1 and Th2 development, respectively, from naive CD4+ T cells primed with anti-CD3 and splenic antigen-presenting cells (APC). The effect was indicated to be indirect via suppression of IL-12 production and augmentation of IL-10 production of APC, which are critical for the Th1 and Th2 development, respectively. Such modulation of cytokine production by EDC was associated with reduction of intracellular glutathione levels in APC. IL-10 deprivation or the addition of N-acetylcysteine, which replenishes intracellular glutathione level during priming, cancelled the effect of EDC on the promotion of Th2 polarization. Oral administration of TBT, which most effectively promoted Th2 polarization in vitro, exacerbated airway inflammation in a murine model of allergic asthma with concomitant enhancement of Th2-type immunity. Collectively these results suggest that EDC such as benzophenone, p-octylphenol, and TBT promote Th2 polarization indirectly via the depletion of glutathione in APC and subsequent modulation of IL-10 and IL-12 production that might result in the exacerbation of allergic diseases.

Animals↗

PubMed2006

Promoter activity and chromosomal location of the Rana rugosa P450 aromatase (CYP19) gene.

Sex is determined genetically in amphibians, but is reversed occasionally by steroid hormones. The phenotypic sex of some amphibian species can be reversed from male to female by estrogens. Estrogens, which are synthesized from testosterone irreversibly by the enzyme P450 aromatase (CYP19), are essential for ovarian development in vertebrates. CYP19 expression is reportedly regulated by steroidogenic factor-1 (SF-1), also designated as Ad4BP, in fish and mammals. However, it is unknown if this is also the case in amphibians. Thus, to elucidate the role of SF-1 in CYP19 gene expression in the gonad of amphibians, it is necessary to isolate and characterize the promoter region of the CYP19 gene of amphibians. For this purpose, we first cloned the promoter region of CYP19 from genomic DNA fragments of the frog Rana rugosa. As a result, a potential binding site of SF-1 was found in the region. When a luciferase promoter assay in HEK 293 cells was carried out to examine the ability of SF-1 as a transcriptional regulator, we found that R. rugosa SF-1 stimulated the expression of the CYP19 gene of the tilapia Oreochromis niloticus, but not that of the frogs R. rugosa and Xenopus laevis. RT-PCR analysis revealed that CYP19 mRNA was expressed at a higher level in the indifferent gonads of females than in those of males. This was also true to SF-1 mRNA In addition, FISH analysis showed that the CYP19 gene was located on chromosome 3 of R. rugosa. Taken together, our data suggest that CYP19, an autosomal gene, is expressed in the undifferentiated gonads to an extent greater in females than in males, but its expression probably is not regulated by SF-1 alone. Another factor(s) may be required if SF-1 promotes the expression of the CYP19 gene in R. rugosa as it does in fish and mammals.

Animals↗

PubMed2006

Fulminant liver failure triggered by therapeutic antibody treatment in a mouse model.

Monoclonal antibodies are finding ever increasing therapeutic applications. However, lethal liver damage has been reported following monoclonal antibody (mAb) treatment in combination with subtoxic doses of cytotoxic drugs. In this study, mice were intravenously injected with 200 microg/mouse of anti-CD8 (anti-Lyt-2.2), anti-CD4 (GK1.5) or anti-B220 (RA3-6B2) mAb. Subsequently, mice were administered 15 mg azoxymethane (AOM) per kg body weight by subcutaneous injection. Unexpectedly, all mice pretreated with mAb died within 72 h of a single injection of AOM. The injection of mAb-coated spleen cells accelerated the induction and the severity of liver disease. We found that mAb treatment activates Kupffer cells to produce inflammatory cytokines such as TNF-alpha and IL-12, and induces the expression of FasL on Kupffer and NKT cells. The concomitant upregulation of Fas on hepatocytes increases the susceptibility of the liver to apoptotic signals, and subsequent treatment with AOM causing mitochondrial injury synergistically induces lethal liver damage. Consistently, the lethal liver damage was abrogated in mice which were deficient for Kupffer cells, NKT cells or Fas-antigen. In conclusion, we have demonstrated a potential risk of lethal fulminant liver damage in the concomitant use of therapeutic antibodies and cytotoxic drugs. A possible side effect of antibody therapy is mediated through activation of the immune system, the very mechanism of action on which this treatment depends. In this context, the risk of combining therapeutic antibodies with other agents, particularly cytotoxic drugs, requires careful consideration.

Animals↗

PubMed2005

IFN-gamma controls the generation/activation of CD4+ CD25+ regulatory T cells in antitumor immune response.

Immunization with serological identification of Ags by recombinant expression cloning (SEREX)-defined self-Ags leads to generation/activation of CD4+ CD25+ regulatory T cells with suppressive activities and enhanced expression of Foxp3. This is associated with increased susceptibility to pulmonary metastasis following challenge with syngeneic tumor cells and enhanced development of 3-methylcholanthrene-induced primary tumors. In contrast, coimmunization with the same SEREX-defined self-Ags mixed with a CTL epitope results in augmented CTL activity and heightened resistance to pulmonary metastasis, both of which depend on CD4+ Th cells. These active regulatory T cells and Th cells were derived from two distinct CD4+ T cell subsets, CD4+ CD25+ T cells and CD4+ CD25- T cells, respectively. In the present study, IFN-gamma was found to abrogate the generation/activation of CD4+ CD25+ regulatory T cells by immunization with SEREX-defined self-Ag. CD4+ CD25+ T cells from these IFN-gamma-treated mice failed to exhibit immunosuppressive activity as measured by 1) increased number of pulmonary metastasis, 2) enhanced development of 3-methylcholanthrene-induced primary tumors, 3) suppression of peptide-specific T cell proliferation, and 4) enhanced expression of Foxp3. The important role of IFN-gamma produced by CD8+ T cells was shown in experiments demonstrating that CD4+ CD25+ T cells cotransferred with CD8+ T cells from IFN-gamma(-/-) mice, but not from wild-type BALB/c mice, became immunosuppressive and enhanced pulmonary metastasis when recipient animals were subsequently immunized with a SEREX-defined self-Ag and a CTL epitope. These findings support the idea that IFN-gamma regulates the generation/activation of CD4+ CD25+ regulatory T cells.

Animals↗

PubMed2005

A novel role for Notch ligand Delta-1 as a regulator of human Langerhans cell development from blood monocytes.

Human Langerhans cells (LCs) are of hematopoietic origin, but cytokine regulation of their development is not fully understood. Notch ligand Delta-1 is expressed in a proportion of the skin. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor-beta1 (TGF-beta1) are also secreted in the skin. We report here that Delta-1, in concert with GM-CSF and TGF-beta1, induces the differentiation of human CD14(+) blood monocytes into cells that express LC markers: CD1a, Langerin, cutaneous lymphocyte-associated antigen, CC chemokine receptor 6, E-cadherin, and Birbeck granules. The resulting cells display phagocytic activity and chemotaxis to macrophage inflammatory protein-1alpha (MIP-1alpha). In response to CD40 ligand and tumor necrosis factor alpha, the cells acquire a mature phenotype of dendritic cells that is characterized by up-regulation of human leukocyte antigen (HLA)-ABC, HLA-DR, CD80, CD86, CD40, and CD54 and appearance of CD83. These cells in turn show chemotaxis toward MIP-1beta and elicit activation of CD8(+) T cells and T helper cell type 1 polarization of CD4(+) T cells. Thus, blood monocytes can give rise to LCs upon exposure to the skin cytokine environment consisting of Delta-1, GM-CSF, and TGF-beta1, which may be, in part, relevant to the development of human epidermal LCs. Our results extend the functional scope of Notch ligand delta-1 in human hematopoiesis.

Amyloid Precursor Protein Secretases↗

PubMed2005

Accelerated chemically induced tumor development mediated by CD4+CD25+ regulatory T cells in wild-type hosts.

We examined the role of CD4+CD25+ regulatory T cells in the development of 3-methylcholanthrene (MCA)-induced tumors. Immunization of wild-type BALB/c mice with a series of SEREX (serological identification of antigens by recombinant expression cloning)-defined broadly expressed self-antigens results in the development of highly active CD4+CD25+ regulatory T cells. Accelerated tumor development was observed in mice immunized with self-antigens and was abolished by antibody-mediated depletion of CD4+ T cells or CD25+ T cells. A similar acceleration of tumorigenesis was also observed in mice adoptively transferred 2 or 4 weeks after MCA injection with CD4+CD25+ T cells derived from mice immunized with DnaJ-like 2, one of these self-antigens. Experiments with Jalpha281-/- mice lacking invariant natural killer (iNK) T cells indicated that iNK T cells, known for their protective role in the development of MCA-induced tumors, were suppressed in immunized hosts. NK cells, also known to play a protective role in MCA induced-tumorigenesis, were also suppressed in mice immunized with serologically defined self-antigens in a CD4+CD25+ T cell-dependent manner. We propose that CD4+CD25+ regulatory T cells generated by immunization with these self-antigens enhance susceptibility to MCA induced-tumorigenesis by down-regulating iNK T and NK reactivity, and suggest that these observations provide direct evidence for the existence of cancer immunosurveillance in this system of chemical carcinogenesis.

Animals↗

PubMed2005

Definition of target antigens for naturally occurring CD4(+) CD25(+) regulatory T cells.

The antigenic targets recognized by naturally occurring CD4(+) CD25(+) regulatory T cells (T reg cells) have been elusive. We have serologically defined a series of broadly expressed self-antigens derived from chemically induced mouse sarcomas by serological identification of antigens by recombinant expression cloning (SEREX). CD4(+) CD25(+) T cells from mice immunized with SEREX-defined self-antigens had strong suppressive activity on peptide-specific proliferation of CD4(+) CD25(-) T cells and CD8(+) T cells. The suppressive effect was observed without in vitro T cell stimulation. Foxp3 expression in these CD4(+) CD25(+) T cells from immunized mice was 5-10 times greater than CD4(+) CD25(+) T cells derived from naive mice. The suppressive effect required cellular contact and was blocked by anti-glucocorticoid-induced tumor necrosis factor receptor family-related gene antibody. In vitro suppressive activity essentially disappeared 8 wk after the last immunization. However, it was regained by in vitro restimulation with cognate self-antigen protein but not with control protein. We propose that SEREX-defined self-antigens such as those used in this study represent self-antigens that elicit naturally occurring CD4(+) CD25(+) T reg cells.

Animals↗

PubMed2005

Inducible nitric oxide synthase-dependent DNA damage in mouse model of inflammatory bowel disease.

Increased cancer risk occurs in inflammatory bowel disease (IBD) undergoing long-term chronic inflammation. To evaluate whether inducible nitric oxide synthase (iNOS)-dependent DNA damage plays a role in the carcinogenic process triggered by IBD, we prepared a mouse model of IBD induced by transfer of CD45RBhighCD4+ T cells lacking regulatory T cells to female severe combined immunodeficiency (SCID) mice. CD45RBhighCD4+ T cells were isolated from mouse spleen after staining with fluorescein isothiocyanate (FITC)-conjugated anti-CD45RB monoclonal antibody, followed by anti-FITC-conjugated microbeads. This IBD mouse model showed that the bodyweight increased with aging to a lesser extent than non-treated controls, and that the intestine was shortened. Pathological findings of this mouse model, which showed severe inflammation in colon tissues, were similar to IBD patients. Double immunofluorescence technique revealed that both 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) were formed mainly in epithelial cells of the IBD mouse model. 8-Nitroguanine was formed in most of 8-oxodG-immunoreactive nuclei of epithelial cells. iNOS, proliferating cell nuclear antigen and p53 protein were also expressed in the colon epithelium. These results indicate that nitrative DNA damage, as well as oxidative DNA damage, is induced in colon epithelial cells of the IBD mouse model followed by proliferation of these cells, which may contribute to colon carcinogenesis.

Aging↗

PubMed2005

Molecular cloning and expression in gonad of Rana rugosa WT1 and Fgf9.

Sry (sex-determining region on the Y chromosome) is required for testicular differentiation in mammals. In addition to Sry, other genes such as WT1, Fgf9, Dax1, Dmrt1 and Sox9 are widely accepted to be involved in the sex determination in vertebrates. However, the roles of these genes during sex determination still remain unclear in amphibians. This study was undertaken to examine the expression of WT1 and Fgf9 in the developing gonad of amphibians. We first isolated the WT1 cDNA from the frog Rana rugosa. Like WT1 in mice, R. rugosa WT1 showed 2 isoforms; i.e., one had an additional 3 amino acids, KTS, included between the third and fourth zinc fingers. However, 17 amino acids in exon 5 of mammalian WT1 could not be found in R. rugosa WT1, which is also the case in turtle and chicken. The mRNA of both isoforms (+KTS, -KTS) was detected in the lung, kidney and testis, but not in the ovary and muscle of adult frogs. The 2 isoforms were expressed first in the embryos at stage 23. Thereafter, the expressions remained constant in the gonad attached to mesonephros of both sexes during sex determination. We next isolated the R. rugosa Fgf9 cDNA encoding 208 amino acids. The amino acid sequence of Fgf9 had similarity greater than 92% with chicken, mouse and human Fgf9s, suggesting that Fgf9 is highly conserved among vertebrate classes. Fgf9 was expressed in the ovary of an adult frog strongly, but in the lung weakly. In contrast, the Fgf9 mRNA was hardly detected in the kidney, testis and muscle. Moreover, Fgf9 did not show a sexually dimorphic expression pattern during sex determination in R. rugosa. The results, taken together, suggest that both WT1 and Fgf9 are expressed in the indifferent gonad prior to sex determination without any difference in the expression between males and females. Thus, it seems unlikely that they are a key factor to initiate the divergence leading to testicular or ovarian differentiation in R. rugosa.

Amino Acid Sequence↗

PubMed2004

Environmental pollutant tributyltin promotes Th2 polarization and exacerbates airway inflammation.

It has been shown that a relatively high dose of tributyltin (TBT), which is recognized as a particularly notable environmental pollutant, exerts immunotoxic effects such as thymic atrophy via induction of T cell apoptosis. However, the effect of low doses of TBT on the immune responses remains unknown. Here we show that environmentally relevant doses of TBT promoted strong Th2 polarization via suppression and augmentation of Th1 and Th2 development, respectively, from naive CD4(+) T cells primed with anti-CD3 and splenic antigen-presenting cells (APC). TBT-induced Th2 polarization was indirect, working through APC via suppression of IL-12 production by macrophages/DC and the augmentation of IL-10 production by B cells. Th2 polarization was also induced in mice treated with TBT and immunized with OVA or infected with Nippostrongylus brasiliensis. Furthermore, airway inflammation in mice sensitized and challenged with OVA was exacerbated by the administration of TBT with concomitant augmentation of Th2-type immunity. Our results highlight the fact that an important environmental pollutant TBT may present significant risk for the induction of allergic diseases via promotion of Th2 polarization.

Animals↗

PubMed2003

Essential roles of tumor-derived helper T cell epitopes for an effective peptide-based tumor vaccine.

In this study, we identified a c-erbB-2/HER2/neu (HER2)-derived Th epitope (HER2 (16-30) ) and examined the role of Th epitopes in HER2-specific CD8+ T cell induction and in vivo tumor eradication, with a particular emphasis on the role of tumor cell-derived Th epitopes. Immunization of BALB/c mice using a mixture of Th epitope HER2 (16-30) and CTL epitope HER2 (63-71) administered subcutaneously with murine GM-CSF (mGM-CSF) induced a much higher level of HER2 (63-71) -specific CD8+ T cells compared with that obtained with the CTL epitope alone. HER2-unrelated OVA-derived Th epitope (OVA (323-339) ) exhibited a similar enhancing effect on HER2 (63-71) -specific CD8+ T cell induction. However, only mice immunized with HER2 (16-30) and HER2 (63-71), but not with a tumor-unrelated OVA (323-339) and HER2 (63-71), showed in vivo eradication of CMS5mHE tumor cells expressing HER2 but not OVA. This distinction was observed in preventative as well as therapeutic experimental settings. Conversely, both HER2 (16-30) and OVA (323-339) Th epitopes were equally effective in inducing the eradication of CMS5mHEOVA tumor cells which express HER2 as well as OVA. Our results clearly indicate that CTL and Th epitopes of target tumor cell origin should be used for effective induction of in vivo antitumor immunity.

Animals↗

PubMed2003

Inhibition of hydroxymethylglutaryl-coenzyme a reductase reduces Th1 development and promotes Th2 development.

Several prospective clinical studies have indicated that hydroxymethylglutaryl-coenzyme A reductase inhibitors, statins, prevent cardiovascular events in part through their antiinflammatory properties. Because inflammation is positively and negatively regulated by T helper (Th) 1 cells and Th2 cells, respectively, we examined the effects of statins on the Th polarization in vitro and in vivo. Here we demonstrated that the statins tested, ie, cerivastatin, simvastatin, lovastatin, and atorvastatin, promoted Th2 polarization through both inhibition of Th1 development and augmentation of Th2 development of CD4+ T cells primed in vitro with anti-CD3 antibody and splenic antigen-presenting cells. Cerivastatin exerted most potent effect on modulation of Th1/Th2 development, and the effect was completely abrogated by an addition of mevalonate. Consistent with in vitro experiments, cerivastatin treatment decreased IFN-gamma production of lymph node cells from mice immunized with ovalbumin emulsified in complete Freund's adjuvant, indicating that Th1 development is also suppressed in an in vivo proinflammatory environment. In this murine model, cerivastatin significantly reduced mesangial matrix expansion of glomeruli in the kidney and attenuated proteinuria. The decrease of glomerular sclerosis by cerivastatin treatment was positively related to the suppression of interferon (IFN)-gamma-producing Th1 response in draining lymph node cells. Hence, these findings strongly suggest that statins' inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase regulates Th1/Th2 polarization in vivo and such a mechanism possibly plays a pathophysiological role in immune-related glomerular injury.

Animals↗

PubMed2003

CD4+ CD25+ T cells responding to serologically defined autoantigens suppress antitumor immune responses.

A variety of tumor-derived antigens have been defined by IgG antibodies in tumor bearers' sera with serological identification of antigens by recombinant expression cloning (SEREX), a serological expression cloning method. The majority of these antigens show no structural abnormality and seem to be wild-type autoantigens. Coimmunization with DNA encoding these autoantigens and tumor-specific cytotoxic T lymphocytes epitopes heightened CD8+ T cell responses and increased resistance to tumor challenge in a CD4+ T cell-dependent manner. In contrast, immunization with these SEREX-defined autoantigens alone leads to heightened susceptibility to tumor challenge. This suppressive effect of immunization is mediated by CD4+ CD25+ T cells. In mice immunized with one of the SEREX-defined autoantigens, Dna J-like 2, the number of alpha-GalCer/CD1d tetramer+ CD3+ T cells [representing natural killer T (NKT) cells] was reduced in the pulmonary compartment, whereas no evident change in the number of other T cell subsets was observed. Experiments with Jalpha281-/- mice lacking most NKT cells indicate that NKT cells are primarily responsible for metastasis suppression and that their activity is inhibited by immunization with Dna J-like 2. We propose that SEREX identifies a pool of autoantigens that maintains and regulates immunological homeostasis via CD4+ CD25+ regulatory T cells.

Adoptive Transfer↗

PubMed2003

Computational flow visualization in vibrating flow pump type artificial heart by unstructured grid.

Computational flow visualization in the casing of vibrating flow pump (VFP) was made for various conditions based on the novel techniques of fluid dynamics. VFP type artificial heart can generate the oscillated flow and can be applied to the left ventricular assist device. Flow pattern of blood in an artificial heart is closely connected to mechanical performance and serious biomechanical problems such as hemolysis and blood coagulation. To effectively design the VFP for a left ventricular assist device, the numerical codes for solving Navier-Stokes equations were developed for three-dimensional blood flow based on the finite volume method. Furthermore, the simulation techniques based on the artificial compressibility method and the unstructured grid were also developed here. The numerical calculations were based on the precise configurations and the flow conditions of the prototype device. From the viewpoint of computational fluid dynamics (CFD), the detailed discussion of flow patterns in the casing of VFP, which were closely connected with hemolysis and blood coagulation, was made and the computational results were visualized by the use of the recent technique of computational graphics. Some useful design data of VFP were presented.

Blood Flow Velocity↗

PubMed2002

Effective anti-tumor adoptive immunotherapy: utilization of exogenous IL-2-independent cytotoxic T lymphocyte clones.

To attain one of the final goals for cancer immunotherapy, cytotoxic T lymphocyte (CTL) clones were selected on the basis of exogenous IL-2 independence after limiting dilution culture from mixed lymphocyte tumor cell culture cells of FBL-3 tumor-immune spleens. About 10% of the clones could be propagated up to >5 times by weekly passages in the presence of splenic feeder and stimulating tumor cells. Two of the representative FBL-3-specific CTL clones that were able to undergo the fifth passage were expanded in large numbers for adoptive transfer by two rounds of a weekly passage with medium containing IL-2. FBL-3-specific CTL clones thus obtained showed a strong ability to eliminate the established tumors when transferred into tumor-bearing nude mice. In addition, the cells were recovered from the mouse spleen even 8 months after the transfer. The most striking differences between the CTL clones used in this experiment and those maintained conventionally in the presence of IL-2 were the abilities to produce IL-2 by themselves and the high expression level of the integrin molecule, VLA-4, that disappeared when cultured completely in the continuous presence of IL-2 in vitro during 12 weeks. In addition, concomitant with the disappearance of exogenous IL-2 independence and VLA-4 expression, the CTL clones lost their capacity to eradicate the tumor in vivo. Thus, the higher capacity of CTL clones to produce IL-2 on their own seemed to be correlated with the in vivo efficacy for tumor eradication and the long-term maintenance of their physiological profiles typical of memory T cells.

Adoptive Transfer↗