Jun Yamanouchi

Ehime University, Matuyama, Ehime, Japan

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Publications (54)316.54 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We investigated whether a prevalent epitope of the β-cell-specific autoantigen islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP206-214) reaches regional Ag-presentation pathways via unprocessed polypeptide chains, as free IGRP206-214 peptide or via preformed IGRP206-214/K(d) complexes. This was accomplished by expressing bacterial artificial chromosome transgenes encoding wild-type (stable) or ubiquitinated (unstable) forms of IGRP in IGRP-deficient NOD mice carrying MHC class I-deficient β-cells, dendritic cells, or B cells. We investigated the ability of the pancreatic lymph nodes of these mice to prime naive IGRP206-214-reactive CD8(+) T cells in vivo, either in response to spontaneous Ag shedding, or to synchronized forms of β-cell necrosis or apoptosis. When IGRP was made unstable by targeting it for proteasomal degradation within β-cells, the cross-priming, autoimmune-initiating potential of this autoantigen (designated autoantigenicity) was impaired. Yet at the same time, the direct presentation, CTL-targeting potential of IGRP (designated pathogenicity) was enhanced. The appearance of IGRP206-214 in regional Ag-presentation pathways was dissociated from transfer of IGRP206-214 or IGRP206-214/K(d) from β cells to dendritic cells. These results indicate that autoantigenicity and pathogenicity are separable and inversely related properties and suggest that pathogenic autoantigens, capable of efficiently priming CTLs while marking target cells for CTL-induced killing, may have a critical balance of these two properties.
    Journal of immunology (Baltimore, Md. : 1950). 08/2014;
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    ABSTRACT: Dear Editor,Iron deficiency anemia (IDA) is one of the most common nutritional diseases worldwide. The basic treatment for IDA is oral iron medication; however, some patients with IDA are occasionally refractory to this type of therapy [1]. Recently, the role of Helicobacter pylori in the etiology of IDA has become a focus of considerable interest [2, 3]. Although the association of H. pylori with IDA has been examined extensively, most studies have focused on mild IDA in school-aged children and young people [4–6]. Here, we report two adult cases of severe IDA refractory to oral iron therapy in which the anemia was dramatically and promptly improved by H. pylori eradication (Fig. 1).Fig. 1Clinical courses of cases 1 and 2. Refractory IDA was promptly improved by oral iron administration after H. pylori eradication and did not recur after withdrawal of iron therapy in both casesCase 1A 73-year-old male was referred to our hospital because of severe anemia. He had been receiving oral ir
    Annals of Hematology 03/2014; · 2.87 Impact Factor
  • Haemophilia 03/2014; 20(2):e179-82. · 3.17 Impact Factor
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    ABSTRACT: Zinc finger protein 521 (ZFP521) regulates a number of cellular processes in a wide range of tissues, such as osteoblast formation and adipose commitment and differentiation. In the field of neurobiology, it is reported to be an essential factor for transition of epiblast stem cells into neural progenitors in vitro. However, the role of ZFP521 in the brain in vivo still remains elusive. To elucidate the role of ZFP521 in the mouse brain, we generated mice lacking exon 4 of the ZFP521 gene. The birth ratio of our ZFP521Δ/Δ mice was consistent with Mendel's laws. Although ZFP521Δ/Δ pups had no apparent defect in the body and were indistinguishable from ZFP521+/+ and ZFP521+/Δ littermates at the time of birth, ZFP521Δ/Δ mice displayed significant weight reduction as they grew, and most of them died before 10 weeks of age. They displayed abnormal behavior, such as hyper-locomotion, lower anxiety and impaired learning, which correspond to the symptoms of schizophrenia. The border of the granular cell layer of the dentate gyrus in the hippocampus of the mice was indistinct and granular neurons were reduced in number. Furthermore, Sox1-positive neural progenitor cells in the dentate gyrus and cerebellum were significantly reduced in number. Taken together, these findings indicate that ZFP521 directly or indirectly affects the formation of the neuronal cell layers of the dentate gyrus in the hippocampus, and thus ZFP521Δ/Δ mice displayed schizophrenia-relevant symptoms. ZFP521Δ/Δ mice may be a useful research tool as an animal model of schizophrenia.
    PLoS ONE 01/2014; 9(3):e92848. · 3.53 Impact Factor
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    ABSTRACT: STAT3 is a key modulator of activation and differentiation of macrophages. But it is still unknown if deficiency of STAT3 activates macrophages to destroy erythrocytes by phagocytosis. We generated STAT3 conditional knockout mice by crossing floxed STAT3 mice with Tie2 promoter-driven Cre-recombinase transgenic mice and clarified that Stat3 plays a critical role in the formation and activation of macrophages. Blood cell count, reticulocyte count, serum lactate dehydrogenase, erythropoietin, iron and ferritin concentration, and life span of the erythrocytes in Tie2 promoter-driven STAT3 conditional knockout mice were analyzed. To explore the erythropoietic function of the mice, we subjected them to brief hemolytic anemia by injecting them intraperitoneally with phenylhydrazine. The fragility of erythrocytes was examined by scanning electron microscopy and osmotic tolerance test. The conditional knockout mice had mild normocytic anemia. They also displayed higher lactate dehydrogenase, ferritin and erythropoietin concentration, higher reticulocyte count, and a shorter lifespan of erythrocytes compared with wild-type controls. These data suggest that destruction of erythrocytes and secondary blood formation were accelerated in the STAT3 conditional knockout mice. It didn't appear due to the fragility of erythrocytes. A few of the conditional knockout mice suddenly developed acute severe anemia, high body temperature and massive splenomegaly, and died within 2 weeks after the onset of anemia. This study provided evidence that STAT3 have a critical role in the destruction of erythrocytes by resident macrophages in the spleen.
    Life sciences 08/2013; · 2.56 Impact Factor
  • Annals of Hematology 07/2013; · 2.87 Impact Factor
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    ABSTRACT: Polymorphisms in MHC class II molecules, in particular around β-chain position-57 (β57), afford susceptibility/resistance to multiple autoimmune diseases, including type 1 diabetes, through obscure mechanisms. Here, we show that the antidiabetogenic MHC class II molecule I-A(b) affords diabetes resistance by promoting the differentiation of MHC-promiscuous autoreactive CD4(+) T cells into disease-suppressing natural regulatory T cells, in a β56-67-regulated manner. We compared the tolerogenic and antidiabetogenic properties of CD11c promoter-driven transgenes encoding I-A(b) or a form of I-A(b) carrying residues 56-67 of I-Aβ(g7) (I-A(b-g7)) in wild-type nonobese diabetic (NOD) mice, as well as NOD mice coexpressing a diabetogenic and I-A(g7)-restricted, but MHC-promiscuous T-cell receptor (4.1). Both I-A transgenes protected NOD and 4.1-NOD mice from diabetes. However, whereas I-A(b) induced 4.1-CD4(+) thymocyte deletion and 4.1-CD4(+)Foxp3(+) regulatory T-cell development, I-A(b-g7) promoted 4.1-CD4(+)Foxp3(+) Treg development without inducing clonal deletion. Furthermore, non-T-cell receptor transgenic NOD.CD11cP-I-A(b) and NOD.CD11cP-IA(b-g7) mice both exported regulatory T cells with superior antidiabetogenic properties than wild-type NOD mice. We propose that I-A(b), and possibly other protective MHC class II molecules, afford disease resistance by engaging a naturally occurring constellation of MHC-promiscuous autoreactive T-cell clonotypes, promoting their deviation into autoregulatory T cells.
    Proceedings of the National Academy of Sciences 02/2013; 110(9):3471-6. · 9.81 Impact Factor
  • Thrombosis Research 02/2013; · 3.13 Impact Factor
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    ABSTRACT: BACKGROUND: Febrile neutropenia (FN) is one of the serious complications of chemotherapy. However, the hematological nadir after chemotherapy and the timing of prophylaxis for FN remain unclear, especially for outpatients. METHODS: We prospectively analyzed laboratory data from outpatients treated with a single chemotherapy regimen, rituximab (R)-CHOP, on three consultation days (days 8, 10, and 15) after chemotherapy to identify any factors that might predict the onset of the hematological nadir and the optimal timing of G-CSF prophylaxis. RESULTS: A total of 100 courses of chemotherapy (total 33 patients) were analyzed. Onset of the hematological nadir was not predictable in any of the patients who had a white blood cell count (WBC) of >5,500 × 10(6)/L and/or monocyte count of >80 × 10(6)/L on day 8, and thus there was little opportunity for G-CSF prophylaxis in each treatment course. Among patients who had a WBC count of 1,500-5,500 × 10(6)/L on day 8, the monocyte count on day 8 was significantly associated with the hematological nadir. Patients who had a monocyte count of <5 × 10(6)/L on day 8, were identified as a high-risk group for neutropenia for whom G-CSF administration during the current treatment course should be considered. CONCLUSION: Our results indicate that, in outpatients receiving R-CHOP chemotherapy, the monocyte count on day 8 is a useful marker of the hematological nadir, allowing an opportunity for G-CSF prophylaxis.
    International Journal of Clinical Oncology 02/2013; · 1.41 Impact Factor
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    ABSTRACT: About 20% of TTP are resistant to plasma exchange. As reported in a few case reports and small case series, rituximab has been used in the treatment of TTP with some benefit. However, the optimal dosing, frequency, and timing of rituximab remain to be determined. We treated three cases of refractory TTP with rituximab. Case 1 exhibited brain sequelae probably due to the late administration of rituximab, case 2 died before the expected effect of rituximab could occur, and case 3 recovered completely because of the early administration of rituximab. These results suggest that rituximab should be given as early as possible in TTP, but large clinical studies are required to determine the optimal use of rituximab in TTP.
    [Rinshō ketsueki] The Japanese journal of clinical hematology 02/2013; 54(2):205-9.
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    ABSTRACT: IL-2 plays a critical role in both effector T-cell development and FoxP3(+) CD4(+) Treg-cell homeostasis. A reduction in Il2 transcription results in impaired FoxP3(+) CD4(+) Treg-cell recruitment and function, and accounts for the association between murine Il2 and type 1 diabetes (T1D). The progression of T1D elicits a disease-countering negative feedback regulatory loop that involves the differentiation of low-avidity autoreactive CD8(+) T cells into memory-like autoregulatory T cells in a CD4(+) Th-dependent manner. Since these autoregulatory T cells express IL-2Rβ (CD122), we hypothesized that their development might also be regulated by IL-2. Here, we investigate the effects of differences in IL-2 expression on this autoregulatory subset. We show that decreased IL-2 production impairs the regulatory capacity of memory-like autoregulatory CD8(+) CD122(+) T cells. Surprisingly, we also find that a reduction in IL-2 production capacity increases memory autoregulatory CD8(+) T-cell formation indirectly, by decreasing the development and function of FoxP3(+) Treg cells in NOD mice. These results illustrate a complex homeostatic interplay between IL-2, CD4(+) Th cells, FoxP3(+) CD4(+) Treg cells and autoregulatory CD8(+) T-cell memory whereby IL-2 controls the function of both Treg-cell subsets, but IL-2-potentiation of FoxP3(+) CD4(+) Treg-cell function results in the suppression of CD4(+) Th-cell activation and autoregulatory memory CD8(+) T-cell formation.
    European Journal of Immunology 11/2012; · 4.97 Impact Factor
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    ABSTRACT: Activation-induced cytidine deaminase (AID/AICDA) is required for somatic hypermutation and class-switch recombination of the immunoglobulin gene, and for c-myc translocation of germinal center-derived B-cell lymphoma. In the present study, we attempted to clarify the significance of AID associated with c-myc in the progression of follicular lymphoma (FL) using RT-PCR and quantitative real-time PCR. Tissues from the patients with grade 3 FL expressed relatively higher levels of c-myc and AID. The samples taken from a patient with FL who died within 2 years after the start of treatment showed either no or low expression of AID, despite expressing high levels of c-myc. In order to examine the role of AID expression in rapidly progressive FL, the full-length AID transcript was transfected into AID-negative cell lines established from different patients with rapidly progressive FL. This led to the establishment of AID-expressing transfectants with a low proliferation rate and a significantly increased incidence of G(0)/G(1) arrest compared with controls. Our results indicate that AID may act as a negative regulator of cell survival in FL when sufficient c-myc is expressed. Switch-off or low expression of AID after c-myc amplification may correlate with the clinical outcomes of FL.
    Cancer Science 12/2011; 103(3):415-21. · 3.48 Impact Factor
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    ABSTRACT: Acute promyelocytic leukemia (APL) is characterized by t(15;17)(q22;q21), which results in the fusion of the promyelocytic leukemia (PML) gene at 15q22 with the retinoic acid alpha-receptor (RARA) at 17q21. We report a patient with APL carrying a new complex variant translocation (5;17;15;20). Spectral karyotyping analysis of bone marrow cells revealed t(5;17;15;20)(q33;q12;q22;q11.2). Fluorescence in situ hybridization with a PML/RARA dual-color DNA probe showed a single fusion signal, and RT-PCR analysis showed PML/RARA fusion transcripts. Complete remission was attained with a course of conventional chemotherapy with all-trans retinoic acid (ATRA). To our knowledge, this is the first report of a four-way translocation of 5q33 and 20q11 involvement in APL.
    International journal of hematology 09/2011; 94(4):395-8. · 1.17 Impact Factor
  • International journal of hematology 08/2011; 94(2):213-5. · 1.17 Impact Factor
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    ABSTRACT: Recent clinical trials have demonstrated that cilostazol, an antiplatelet drug competent to inhibit phosphodiesterase 3, is effective in secondary prevention of atherothrombosis including ischemic stroke, myocardial infarction, and peripheral arterial disease. However, there is no reliable assay for detection of the platelet response to cilostazol. We attempted to establish such an assay for clinical use. Phosphorylation of vasodilator-stimulated phosphoprotein (VASP) subsequent to the pharmacological action of cilostazol was measured by a platelet VASP assay kit that has been widely used for monitoring platelet response to ADP receptor antagonists in clinical settings. We modified the kit and found the optimal conditions for detection of cilostazol-dependent VASP phosphorylation. The assay could detect the in vitro and in vivo platelet responses to cilostazol effectively in the presence of 50 nM PGE1. ROC analysis showed that our assay had 97% sensitivity and 75% specificity when blood drawn between 3 and 9?h after cilostazol ingestion was subjected to the assay. The assay results were verified by immunoblotting specific for VASP phosphorylation. Standard light transmission platelet aggregometry could not detect significant inhibition of agonist-induced platelet aggregation by cilostazol except for the in vitro effect of high concentrations of cilostazol. These results demonstrate that the platelet VASP assay can detect the platelet response to cilostazol with high sensitivity and specificity.
    Platelets 01/2011; 22(2):135-42. · 2.24 Impact Factor
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    ABSTRACT: In order to analyze the clinical activity and cost-effectiveness of granulocyte colony-stimulating factors (G-CSF), the prophylactic usage of G-CSF in patients treated with a single chemotherapy regimen during early courses was prospectively evaluated. Thirty patients with newly diagnosed non-Hodgkin lymphoma (NHL) treated with the first course of an R-CHOP regimen were enrolled randomly. After treatment with the first course of chemotherapy, a daily dose of G-CSF (lenograstim, 100 μg) was administered to half (15 cases) of the patients, and a dose of G-CSF (100 μg) was administered every other day to the other half of the patients when leukocytopenia (<1.5 × 10(9)/L) and/or neutropenia (<0.5 × 10(9)/L) occurred. Changes in leukocyte and neutrophil counts, prophylaxis, febrile neutropenia (FN) events, and cost performance between the two groups were analyzed. No significant difference between the two groups was observed in recoveries of leukocyte and neutrophil counts and evidence of FN. The only difference was the total cost of G-CSF. We concluded that every-other-day use of G-CSF was as clinically effective for the prophylaxis of FN as the daily use of G-CSF, and economically speaking, the administration of G-CSF every other day should be more beneficial for patients with NHL during early courses of R-CHOP chemotherapy.
    International Journal of Clinical Oncology 10/2010; 16(2):118-24. · 1.41 Impact Factor
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    ABSTRACT: This study reports the association of the chromosomal abnormality derivative (1;18)(q10;q10) with essential thrombocythemia (ET) occurring in a 75-year-old woman. Allele-specific polymerase chain reaction also revealed a V617F mutation in the Janus Kinase 2 gene (JAK2) in the platelet compartment in this patient. The der(1;18)(q10;q10) abnormality has previously been reported in two cases of myeloid disorders. The etiological implications for ET of this combination of chromosomal abnormality and JAK2 mutation still remain elusive. This is a novel report of derivative (1;18)(q10;q10) abnormality in ET.
    Cancer genetics and cytogenetics 05/2010; 199(1):62-4. · 1.54 Impact Factor
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    ABSTRACT: A current paradigm states that non-antigen-specific inflammatory cues attract noncognate, bystander T cell specificities to sites of infection and autoimmune inflammation. Here we show that cues emanating from a tissue undergoing spontaneous autoimmune inflammation cannot recruit naive or activated bystander T cell specificities in the absence of local expression of cognate antigen. We monitored the recruitment of CD8(+) T cells specific for the prevalent diabetogenic epitope islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)(206-214) in gene-targeted nonobese diabetic (NOD) mice expressing a T cell "invisible" IGRP(206-214) sequence. These mice developed islet inflammation and diabetes with normal incidence and kinetics, but their inflammatory lesions could recruit neither naive (endogenous or exogenous) nor ex vivo-activated IGRP(206-214)-reactive CD8(+) T cells. Conversely, IGRP(206-214)-reactive, but not nonautoreactive CD8(+) T cells rapidly homed to and accumulated in the inflamed islets of wild-type NOD mice. Our results indicate that CD8(+) T cell recruitment to a site of autoimmune inflammation results from an active process that is strictly dependent on local display of cognate pMHC and suggest that CD8(+) T cells contained in extralymphoid autoimmune lesions are largely autoreactive.
    Proceedings of the National Academy of Sciences 05/2010; 107(20):9317-22. · 9.81 Impact Factor
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    ABSTRACT: Blunting autoreactivity without compromising immunity remains an elusive goal in the treatment of autoimmunity. We show that progression to autoimmune diabetes results in the conversion of naive low-avidity autoreactive CD8(+) T cells into memory-like autoregulatory cells that can be expanded in vivo with nanoparticles coated with disease-relevant peptide-major histocompatibility complexes (pMHC-NP). Treatment of NOD mice with monospecific pMHC-NPs expanded cognate autoregulatory T cells, suppressed the recruitment of noncognate specificities, prevented disease in prediabetic mice, and restored normoglycemia in diabetic animals. pMHC-NP therapy was inconsequential in mice engineered to bear an immune system unresponsive to the corresponding epitope, owing to absence of epitope-experienced autoregulatory T cells. pMHC-NP-expanded autoregulatory T cells suppressed local presentation of autoantigens in an interferon-gamma-, indoleamine 2,3-dioxygenase-, and perforin-dependent manner. Nanoparticles coated with human diabetes-relevant pHLA complexes restored normoglycemia in a humanized model of diabetes. These observations expose a paradigm in the pathogenesis of autoimmunity amenable for therapeutic intervention.
    Immunity 04/2010; 32(4):568-80. · 19.80 Impact Factor
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    ABSTRACT: Human embryonic stem (hES) cells can be differentiated into pancreatic endoderm structures in vitro. The study was performed to determine whether induced pluripotent stem (iPS) cells can be differentiated into similar structures with comparable efficiency. We compared the ability of hES cells and iPS cells derived from human epidermal keratinocytes to progressively differentiate into pancreatic endoderm. Human foreskin keratinocytes were reprogrammed to pluripotency by transduction with retroviruses encoding Oct4, Sox2, and Klf4. The resulting keratinocyte-derived iPS (KiPS) cell lines and a hES cell line were subjected to a modified pancreatic endoderm differentiation protocol. Cells and embryoid-body structures derived from both hES and KiPS cells were compared at different stages of development for expression of stem cell and differentiation markers, including Sox2, Oct4, Mixl1, Brachyury, Gsc, FoxA2, Sox17, Hnf4α, Hnf1β, Nkx2.2, Nkx6.1, Hex, Isl1, Pdx1, and Slc2A, via Taqman real-time PCR, flow-cytometry, and/or immunocytochemistry. hES cells and KiPS cells expressed similar levels of the stem cell factors Sox2 and Oct4. Upon differentiation, both cell types underwent remarkably similar changes in gene expression. They acquired the definitive endoderm markers Sox17 and FoxA2. Most Sox17+ and FoxA2+ cells co-expressed Hnf4α and Hnf1β, found in the primitive gut tube, a pancreas precursor. Most FoxA2+ cells were also Pdx1+, and many expressed Nkx2.2, Nkx6.1, and Isl1. Keratinocyte-derived iPS cells can be differentiated into pancreatic endoderm, and the efficiency of this process is comparable to that seen for hES cells. Thus keratinocytes have the potential to serve as a source of patient-specific pancreatic endoderm for transplantation.
    The Review of Diabetic Studies 01/2010; 7(2):158-67.

Publication Stats

970 Citations
316.54 Total Impact Points

Institutions

  • 2004–2014
    • Ehime University
      • • Department of Bioregulatory Medicine
      • • First Department of Internal Medicine
      Matuyama, Ehime, Japan
  • 2002–2014
    • The University of Calgary
      • • Faculty of Medicine
      • • Department of Microbiology, Immunology and Infectious Diseases
      • • Immunology Research Group (IRG)
      Calgary, Alberta, Canada
  • 2008
    • Hanson Institute
      Tarndarnya, South Australia, Australia
    • CSU Mentor
      Long Beach, California, United States