[Show abstract][Hide abstract] ABSTRACT: Human type 1 diabetes is an autoimmune disease that results from the autoreactive destruction of pancreatic β cells by T cells. Antigen presenting cells including dendritic cells and macrophages are required to activate and suppress antigen-specific T cells. It has been suggested that antigen uptake from live cells by dendritic cells via scavenger receptor class A (SR-A) may be important. However, the role of SR-A in autoimmune disease is unknown. In this study, SR-A-/- nonobese diabetic (NOD) mice showed significant attenuation of insulitis, lower levels of insulin autoantibodies, and suppression of diabetes development compared with NOD mice. We also found that diabetes progression in SR-A-/- NOD mice treated with low-dose polyinosinic-polycytidylic acid (poly(I∶C)) was significantly accelerated compared with that in disease-resistant NOD mice treated with low-dose poly(I∶C). In addition, injection of high-dose poly(I∶C) to mimic an acute RNA virus infection significantly accelerated diabetes development in young SR-A-/- NOD mice compared with untreated SR-A-/- NOD mice. Pathogenic cells including CD4+CD25+ activated T cells were increased more in SR-A-/- NOD mice treated with poly(I∶C) than in untreated SR-A-/- NOD mice. These results suggested that viral infection might accelerate diabetes development even in diabetes-resistant subjects. In conclusion, our studies demonstrated that diabetes progression was suppressed in SR-A-/- NOD mice and that acceleration of diabetes development could be induced in young mice by poly(I∶C) treatment even in SR-A-/- NOD mice. These results suggest that SR-A on antigen presenting cells such as dendritic cells may play an unfavorable role in the steady state and a protective role in a mild infection. Our findings imply that SR-A may be an important target for improving therapeutic strategies for type 1 diabetes.
PLoS ONE 10/2014; 9(10):e109531. DOI:10.1371/journal.pone.0109531 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An emerging infectious disease consisting of hepatic abscess, complicated by central nervous system infection and endophthalmitis, has been reported from East Asia, principally Taiwan. It is caused by a virulent strain of Klebsiella pneumoniae. We report 2 cases from Japan with this triad.
Infectious Disease in Clinical Practice 11/2013; 21(6):380-382. DOI:10.1097/IPC.0b013e318279f167
[Show abstract][Hide abstract] ABSTRACT: A 72-year-old woman with slowly progressive type 1 diabetes (SPIDDM) was admitted to our hospital because of increasing abdominal pain and diarrhea. The patient was diagnosed with nonocclusive mesenteric ischemia (NOMI), and a subtotal colonectomy was performed successfully. The resected sample revealed transmural gangrenous necrosis of the colon and rectum. This case is interesting because the severe NOMI occurred in a SPIDDM patient without common predisposing events such as hypoperfusion. Prolonged generation of reactive oxygen species in SPIDDM, together with the decline in adaptive response to oxidative stress with aging, might be an exacerbating factor for ischemic injury in the elderly.
Internal Medicine 01/2012; 51(9):1065-8. DOI:10.2169/internalmedicine.51.6945 · 0.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Oral intake of nutrients is often compromised in elderly, multimorbid patients, but parenteral nutrition causes intestinal atrophy and impairs intestinal function. To uncover the molecular mechanisms by which amino acids are involved in intestinal atrophy and recovery, we studied whether the rapamycin-sensitive mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) pathway is involved in this process.
C57BL/6N mice were fed a glucose solution alone, glucose solution with amino acids or normal chow diet for various lengths of time. Intestinal sections were prepared from these mice and the villus height and villus density were quantified. As a readout for the mTORC1 pathway, the phosphorylation of the ribosomal S6 protein (S6) was analyzed by immunostaining and immunoblotting. To confirm the role of the mTORC1 pathway, the inhibitory effect of a specific mTOR inhibitor, rapamycin, was examined.
Inducing fasting in mice fed only glucose caused time-dependent intestinal mucosal atrophy, whereas supplementation with amino acids protected the intestinal mucosa from atrophy. Phosphorylation of S6 decreased in the intestinal mucosa of mice fed only glucose, whereas supplementation with amino acids increased S6 phosphorylation. Importantly, intraperitoneal injection of rapamycin attenuated the protective effect of amino acids on the intestinal mucosa in a pattern consistent with the decrease of S6 phosphorylation.
These results indicate that the mTORC1 pathway plays a crucial role in the in vivo maintenance of the intestinal mucosa by the oral intake of amino acids.
[Show abstract][Hide abstract] ABSTRACT: Fulminant Type 1 diabetes was originally reported as idiopathic Type 1 diabetes. Involvement of viral infections in the pathogenesis of fulminant T1D has been suggested, but the development of fulminant Type 1 diabetes after influenza vaccination has not been reported.
We report a case of fulminant Type 1 diabetes with thrombocytopenia following influenza vaccination. A 54-year-old man was admitted to hospital with hyperglycaemia and diabetic ketosis. Seven days before admission, he received a seasonal influenza vaccine for the prevention of influenza infection. On admission, blood glucose was 29 mmol/L and HbA1c 40 mmol/mol (5.9%). Fasting and 2-h C-peptide immunoreactivity were <0.0333 nmol/L and 0.0999 nmol/L, respectively. Anti-GAD and anti-IA-2 antibodies were negative, so no autoimmunity seemed to participate in the etiology. ELISPOT assay also showed no association with T cell-mediated autoimmunity. HLA genotypes were consistent with susceptibility to fulminant Type 1 diabetes. After the abrupt onset of diabetes, he showed mild thrombocytopenia, which has been observed for approximately 5 years after diabetes development.
This is the first description of fulminant Type 1 diabetes after influenza vaccination. Our observation raises the possibility that influenza vaccination might trigger this condition via the TLR7 pathway.
Diabetic Medicine 07/2011; 29(1):88-9. DOI:10.1111/j.1464-5491.2011.03391.x · 3.12 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The protein Ras homolog enriched in brain (Rheb) is a Ras-like small GTPase that activates the mechanistic target of rapamycin complex 1 (mTORC1), which promotes cell growth. We previously generated transgenic C57BL/6 mice overexpressing Rheb in β-cells (B6(Rheb)), which exhibited increased β-cell size and improved glucose tolerance with higher insulin secretion than wild type C57BL/6 mice. The mice also showed resistance to obesity-induced hyperglycemia, a model of type 2 diabetes, and to multiple low-dose-streptozotocin (MLDS)-induced hyperglycemia, a model of type 1 diabetes (T1D). To investigate whether the effects of mTORC1 activation by Rheb in B6(Rheb) mice would also be evident in NOD mice, a spontaneous autoimmune T1D model, we created two NOD mouse lines overexpressing Rheb in their β-cells (NOD(Rheb); R3 and R20). We verified Rheb overexpression in β-cells, the relative activation of mTORC1 and β-cell enlargement. By 35 weeks of age, diabetes incidence was significantly greater in the R3 line and tended to be greater in the R20 line than in NOD mice. Histological analysis demonstrated that insulitis was significantly accelerated in 12-week-old R3 NOD(Rheb) mice compared with NOD mice. Furthermore, serum insulin autoantibody (IAA) expression was significantly higher than that of NOD mice. We also examined whether complete Freund's adjuvant (CFA) treatment alone or with glucagon-like peptide-1 (GLP-1) analog would reverse the hyperglycemia of NOD(Rheb) mice; unexpectedly, almost none achieved normoglycemia. In summary, diabetes progression was significantly accelerated rather than prevented in NOD(Rheb) mice. Our results suggest that the β-cell enlargement might merely enhance the autoimmunity of pathogenic T-cells against islets, leading to acceleration of autoimmune diabetes. We conclude that not only enlargement but also regeneration of β-cells in addition to the prevention of β-cell destruction will be required for the ideal therapy of autoimmune T1D.
Biochemical and Biophysical Research Communications 05/2011; 408(2):306-11. DOI:10.1016/j.bbrc.2011.04.026 · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was to determine whether BMDCs cultured in the presence of IL-10 (G/10-DCs) could promote T cell tolerance and prevent autoimmune diabetes in two different animal models of T1D. Our results showed that G/10-DCs suppressed both insulitis and spontaneous diabetes in NOD and HLA-DQ8/RIP-B7.1 mice. The suppression was likely to be mediated by T cells, as we found that regulatory CD4(+)CD25(+)Foxp3(+) cells were significantly increased in G/10-DC treated animals. In vivo, the G/10-DCs inhibited diabetogenic T cell proliferation; in vitro, they had reduced expression of costimulatory molecules and produced little IL-12/23 p40 or IL-6 but a large amount of IL-10 when compared with DCs matured in the presence of IL-4 (G/4-DC). We conclude that IL-10-treated DCs are tolerogenic and induce islet-directed immune tolerance, which was likely to be mediated by T regulatory cells. This non-antigen-specific DC-based approach offers potential for a new therapeutic intervention in T1D.
[Show abstract][Hide abstract] ABSTRACT: A 62-year-old man was admitted to our hospital because of melena. On admission physical examination revealed that he had typical features of Noonan syndrome (NS). Investigation via upper endoscopy with the single balloon demonstrated oozing from the small intestine. Bleeding sometimes occurs in patients with NS. We speculated that coagulation defects or vascular malformations might have been present at the first visit in this case. However, coagulation function was normal. By upper endoscopy with the single balloon we clearly revealed the angioectasia in the small intestine. This case documents the first association among NS, aortic regurgitation and angioectasia in the small intestine.
Internal Medicine 01/2011; 50(21):2611-3. DOI:10.2169/internalmedicine.50.6076 · 0.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: It is often difficult to diagnose disease in elderly patients, in particular those with dementia, who do not present with typical symptoms. This report describes our experience of an elderly patient (an 83-year-old woman) who presented with a chief complaint of memory loss, showed a marked inflammatory response, and was diagnosed with large-vessel giant cell arteritis (GCA) on the basis of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) findings. She had no symptoms typical of GCA including jaw claudication, visual field defect and heavy headed feeling. Corticosteroid therapy resulted in a trend toward improvement in the inflammatory response and then she first recognized that she might have experienced slight dull headache before treatment of GCA. This was probably because this patient had large-vessel GCA, which produces a few symptoms in the head and neck, and because she had Alzheimer's disease and could not accurately describe her symptoms. Our experience suggests the usefulness of FDG-PET for the diagnosis of GCA, particularly in elderly patients without typical symptoms.
[Show abstract][Hide abstract] ABSTRACT: Antigen-specific regulatory CD4(+) T cells have been described but there are few reports on regulatory CD8(+) T cells. We generated islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)-specific regulatory CD8(+) T cells from 8.3-NOD transgenic mice. CD8(+) T cells from 8.3-NOD splenocytes were cultured with IGRP, splenic dendritic cells (SpDCs), TGF-beta, and all-trans retinoic acid (ATRA) for 5days. CD8(+) T cells cultured with either IGRP alone or IGRP and SpDCs in the absence of TGF-beta and ATRA had low Foxp3(+) expression (1.7+/-0.9% and 3.2+/-4.5%, respectively). In contrast, CD8(+) T cells induced by exposure to IGRP, SpDCs, TGF-beta, and ATRA showed the highest expression of Foxp3(+) in IGRP-reactive CD8(+) T cells (36.1+/-10.6%), which was approximately 40-fold increase compared with that before induction culture. CD25 expression on CD8(+) T cells cultured with IGRP, SpDCs, TGF-beta, and ATRA was only 7.42%, whereas CD103 expression was greater than 90%. These CD8(+) T cells suppressed the proliferation of diabetogenic CD8(+) T cells from 8.3-NOD splenocytes in vitro and completely prevented diabetes onset in NOD-scid mice in cotransfer experiments with diabetogenic splenocytes from NOD mice in vivo. Here we show that exposure to ATRA and TGF-beta induces CD8(+)Foxp3(+) T cells ex vivo, which suppress diabetogenic T cells in vitro and in vivo.
Biochemical and Biophysical Research Communications 03/2010; 394(1):228-32. DOI:10.1016/j.bbrc.2010.02.176 · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Antigen-specific immunotherapy is expected to be an ideal strategy for treating type 1 diabetes (T1D). We investigated the therapeutic efficacy of a peptide in the leader sequence of preproinsulin, which was selected because of its binding affinity to the MHC I-A(g7) molecule. Preproinsulin-1 L7-24 peptide (L7-24) emulsified in Freund's incomplete adjuvant was administered subcutaneously to NOD mice. Administration of L7-24 increased the proportion of regulatory T cells in the spleen. Splenocytes of NOD mice immunized with this peptide secreted IL-4 and IL-10 in response to L7-24. This peptide also significantly prevented the development of diabetes and cured some newly diabetic NOD mice without recurrence. L7-24 peptide, which has a high affinity for pockets of I-A(g7), induced regulatory T cells and showed therapeutic effects. This peptide may provide a new approach for developing antigen-specific immunotherapy for autoimmune diabetes.
[Show abstract][Hide abstract] ABSTRACT: Components of insulin/IGF-1 receptor-mediated signaling pathways in pancreatic beta-cells have been implicated in the development of diabetes, in part through the regulation of beta-cell mass in vivo. Studies in vitro have shown that the protein Ras homolog enriched in brain (Rheb) plays a key role as a positive upstream regulator of the mammalian target of rapamycin complex 1 (mTORC1) pathway in integrating inputs from nutrients and growth factors for cell growth. Our objective was to investigate the role of the mTORC1 pathway in the regulation of beta-cell mass in vivo.
We generated transgenic mice that overexpress Rheb in beta-cells. We examined the activation of the mTORC1 pathway and its effects on beta-cell mass, on glucose metabolism, and on protection against hyperglycemia.
Immunoblots of islet extracts revealed that the phosphorylation levels of ribosomal protein S6 and eukaryotic initiation factor 4E binding protein 1, downstream effectors for mTORC1, were upregulated in transgenic beta-cells. Immunostaining of the pancreatic sections with anti-phospho-S6 antibody confirmed upregulation of the mTORC1 pathway in beta-cells in vivo. The mice showed improved glucose tolerance with higher insulin secretion. This arose from increased beta-cell mass accompanied by increased cell size. The mice also exhibited resistance to hyperglycemia induced by streptozotocin and obesity.
Activation of the mTORC1 pathway by Rheb led to increased beta-cell mass in this mouse model without producing obvious unfavorable effects, giving a potential approach for the treatment of beta-cell failure and diabetes.
[Show abstract][Hide abstract] ABSTRACT: Type 1 diabetes (T1D) is caused mostly by autoimmune destruction of pancreatic beta-cells, the precise mechanism of which remains unclear. Two major effector mechanisms have been proposed: direct cell-mediated and indirect cytokine-mediated cytotoxicity. Cytokine-mediated beta-cell destruction is presumed mainly caused by NO production. To evaluate the role of iNOS expression in T1D, this study used a novel iNOS inhibitor ONO-1714. ONO-1714 significantly reduced cytokine-mediated cytotoxicity and NO production in both MIN6N9a cells and C57BL/6 islets in the presence of IL-1beta, TNF-alpha, and IFN-gamma. To evaluate whether NO contributes to diabetes progression in vivo, ONO-1714 was administered to four different mouse models of autoimmune diabetes: multiple low-dose STZ (MLDS)-induced C57BL/6, CY-induced, adoptive transfer and spontaneous NOD diabetes. Exposure to STZ in vitro induced NO production in MIN6N9a cells and C57BL/6 islets, and in vivo injection of ONO-1714 to MLDS-treated mice significantly reduced hyperglycemia and interestingly, led to complete suppression of cellular infiltration of pancreatic islets. In contrast, when ONO-1714 was injected into spontaneous NOD mice and CY-induced and adoptive transfer models of NOD diabetes, overt diabetes could not be inhibited in these models. These findings suggest that NO-mediated cytotoxicity significantly contributes to MLDS-induced diabetes but not to NOD diabetes.
Diabetes research and clinical practice 02/2009; 83(2):200-7. DOI:10.1016/j.diabres.2008.11.029 · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Insulin has been reported as a major autoantigen in both human and murine type 1 diabetes (T1D). Insulin1-knockout NOD mice with only insulin2 are protected against the development of autoimmune diabetes, suggesting that insulin1 has strong immunogenicity and insulin2 has weak immunogenicity or a possible protective role in the pathogenesis of type 1 diabetes. In this study, we have developed fiber-mutant adenovirus vectors that express murine proinsulin1 or proinsulin2 (named Ad.Pins1-RGD/Ad.Pins2-RGD) and administered those virus vectors to the NOD mouse to evaluate modulation of autoimmune responses. The intravenous administration of either Ad.Pins1-RGD or Ad.Pins2-RGD at 3 and 5 weeks of age strongly suppressed the development of overt diabetes, accompanied by a significant reduction of insulin autoantibody (IAA), and suppression of disease was similar between administration of Ad.Pins1-RGD and that of Ad.Pins2-RGD. Our study suggests that systemic administration of fiber-mutant adenovirus vectors, which induce transient expression of proinsulin, may be applicable to a gene therapy inducing tolerance to insulin.
Annals of the New York Academy of Sciences 01/2009; 1150(1):183-6. DOI:10.1196/annals.1447.006 · 4.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: CD4(+)CD25(+) T cells (Tregs) play a critical role in maintaining dominant peripheral tolerance, and pathogenic autoreactive T cells may be frequent in the CD25-negative fraction of peripheral blood mononuclear cells (PBMCs) from patients with autoimmune disease. We therefore investigated whether T cell autoimmune responses to recombinant GAD65 can be detected by the use of ELISPOT assay in the CD25-negative fraction of PMBCs from Japanese type 1 diabetes (T1D) patients. The frequency of CD4(+)CD25(+) T cells was not different among patients with newly developed T1D, established T1D, and healthy controls. The CD25 positive cell-depleted fraction was obtained by negative selection with antihuman CD25 magnetic beads, reducing the number of CD4(+)CD25(+) T cells from 4-5% to less than 1%. In whole PBMC fraction, there was a significant elevation of IFN-gamma spots in PBMCs from recently diagnosed patients with T1D (P < 0.05), whereas the number of IFN-gamma spots from patients with established T1D was not significant. In the CD25-negative fraction, unlike whole PBMCs, we observed the significant IFN-gamma spots to GAD65 in the fraction from patients with established T1D (P < 0.05), but not in those with recently diagnosed disease. The phenomena were not observed for IL-4 spots. Our data suggest a possible role of Tregs maintaining dominant peripheral tolerance in T1D and application of further improved T cell assay detecting autoimmunity even in established T1D.
Annals of the New York Academy of Sciences 12/2008; 1150(1):278-81. DOI:10.1196/annals.1447.007 · 4.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: InsulinB:9-23 peptide (insB:9-23) reactive T cells has been reported as crucial for type 1 diabetes. In this study, experimental autoimmune diabetes (EAD) mice, which subcutaneous immunization of ins1 or 2B:9-23 induced autoimmune diabetes in F1(B7.1B6 x BALB/c), was investigated for antigen specific therapy to delete pathogenic T cells. Intravenous injection of ins1 or 2B:9-23 significantly delayed the development of diabetes on the corresponding peptide-induced EAD (ins1EAD or ins2EAD) concomitant with reduced insulitis and insulin autoantibodies expression. Population of Foxp3(+) CD4(+) T cell was unchanged whereas the level of anti-insB:9-23 specific IgG(2a) but not IgG(1) were specifically decreased, suggesting reduction of pathogenic insB:9-23 reactive T cells. Most interestingly, intravenous administration of ins2B:9-23, whose amino acid sequence had one amino acid difference at position 9 delayed the development of diabetes in both ins1EAD and ins2EAD whereas ins1B:9-23 administration delayed diabetes in the ins1EAD but not ins2EAD, suggesting that one amino acid difference gives critical influence on the effect of intravenous injection of antigenic peptide for type 1 diabetes.
Biochemical and Biophysical Research Communications 09/2008; 374(3):581-6. DOI:10.1016/j.bbrc.2008.07.066 · 2.30 Impact Factor