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Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Coxsackievirus (CV) is an important human pathogen that has been linked to the development of autoimmunity. An intact pancreatic beta cell IFN response is critical for islet cell survival and protection from type 1 diabetes following CV infection. In this study, we show that IFNs trigger an antiviral state in beta cells by inducing the expression of proteins involved in intracellular antiviral defense. Specifically, we demonstrate that 2',5'-oligoadenylate synthetases (2-5AS), RNase L, and dsRNA-dependent protein kinase (PKR) are expressed by pancreatic islet cells and that IFNs (IFN-alpha and IFN-gamma) increase the expression of 2-5AS and PKR, but not RNase L. Moreover, our in vitro studies uncovered that these pathways play important roles in providing unique and complementary antiviral activities that critically regulate the outcome of CV infection. The 2-5AS/RNase L pathway was critical for IFN-alpha-mediated islet cell resistance from CV serotype B4 (CVB4) infection and replication, whereas an intact PKR pathway was required for efficient IFN-gamma-mediated repression of CVB4 infection and replication. Finally, we show that the 2-5AS/RNase L and the PKR pathways play important roles for host survival during a challenge with CVB4. In conclusion, this study has dissected the pathways used by distinct antiviral signals and linked their expression to defense against CVB4.
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PMID:RNase L and double-stranded RNA-dependent protein kinase exert complementary roles in islet cell defense during coxsackievirus infection. 1566 70

Type 1 diabetes is considered as Th1 cell mediated autoimmune disease and the suppression of Th1 cells or the activation of Th2 cells has been regarded as a plausible immunologic intervention for the prevention of type 1 diabetogenesis in a rodent model. CpG ODN is an immunostimulatory sequence primarily present in bacterial DNA, viral DNA and BCG. CpG ODN is conventionally classified as a Th1 cell activator, which has been clinically applied to cancer, allergy and infectious disease. Recently, there was a promising report of that CpG ODN administration suppressed the development of type 1 diabetes in NOD mice by inducing Th2 cell mediated cytokine. However, the antidiabetogenic effect of CpG ODN on NOD mice is controversial. Thus, two studies were serially undertaken with various kinds of CpG motif to find a more optimal sequence and administration method. In the first study, CpG ODN was vaccinated four times and pancreatic inflammation and the quantity of serum insulin subsequently evaluated. In the second study, the amounts of IFN gamma and IL-4 in sera were measured as representative cytokines of Th1 and Th2 cells, respectively. As a result, vaccination or continuous injection of CpG ODN failed to show a preventive effect on type 1 diabetogenesis in NOD mice. Structural differences of CpG ODN also had no affect on the result. CpG ODN also consistently showed affect on the pancreatic pathology. The productions of IFN gamma and IL-4 were detected only in the K and D type CpG ODN administration groups. Comparison of the two cytokines leads to the conclusion that CpG ODN generated a Th1-weighted response in both study groups. It was assumed that CpG ODN failed to produce Th2-weighted cytokine milieu, which can overcome the genetically determined phenotype of NOD mice. Given these results, it was concluded that the immunotherapeutic application of CpG ODN on Type 1 diabetes had clear limitations.
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PMID:Limited effect of CpG ODN in preventing type 1 diabetes in NOD mice. 1598 4

The autoimmune nature of the diabetogenic process and the major contribution of T lymphocytes stand now beyond any doubt. However, despite the identification of the three major type 1-diabetes-related autoantigens (insulin, GAD65 and phosphatase IA-2), the origin of this immune dysregulation still remains unknown. More and more evidence supports a thymic dysfunction in the establishment of central self-tolerance to the insulin family as a crucial factor in the development of the autoimmune response selective of pancreatic insulin-secreting islet beta cells. All the genes of the insulin family (INS, IGF1 and IGF2) are expressed in the thymus network. However, IGF-2 is the dominant member of this family first encountered by T cells in the thymus, and only IGFs control early T-cell differentiation. IGF2 transcription is defective in the thymus in one animal model of type 1 diabetes, the Bio-Breeding (BB) rat. The sequence B9-23, one dominant autoantigen of insulin, and the homologous sequence B11-25 derived from IGF-2 exibit the same affinity and fully compete for binding to DQ8, one class-II major histocompatibility complex (MHC-II) conferring major genetic susceptibility to type 1 diabetes. Compared to insulin B9-23, the presentation of IGF-2 B11-25 to peripheral mononuclear cells (PBMCs) isolated from type 1 diabetic DQ8+ adolescents elicits a regulatory/tolerogenic cytokine profile (*IL-10, *IL-10/IFN-g, *IL-4). Thus, administration of IGF-2 derived self-antigen(s) might constitute a novel form of vaccine/immunotherapy combining both an antagonism for the site of presentation of a susceptible MHC allele, as well as a downstream tolerogenic/regulatory immune response.
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PMID:[Importance of a thymus dysfunction in the pathophysiology of type 1 diabetes]. 1603 83

The proinflammatory cytokines interleukin-1beta (IL-1beta), interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) are toxic to pancreatic beta-cells and are implicated in the pathogenesis of type 1 diabetes. We have previously found that GH and prolactin (PRL) stimulate both proliferation and insulin production in pancreatic beta-cells and rat insulin-producing INS-1 cells. Here we report that human (h) GH can prevent the apoptotic effects of IL-1beta, IFN-gamma and TNF-alpha in INS-1 and INS-1E cells. Using adenovirus-mediated gene transfer, we found that the anti-apoptotic effect of hGH is abrogated by expression of a dominant negative signal transducer and activator of transcription (STAT5) mutant in INS-1E cells. hGH and the cytotoxic cytokines was found to additively increase suppressor of cytokine signalling-3 mRNA expression after 4 h of exposure. In order to identify possible targets for the STAT5-mediated protection of INS-1E cells, we studied the effect of hGH on activation of the transcription factors STAT1 and nuclear factor-kappaB (NF-kappaB) by IFN-gamma and IL-1beta+TNF-alpha respectively. Gel retardation experiments showed that hGH affects neither IFN-gamma+TNF-alpha-induced STAT1 DNA binding nor IL-1beta and IFN-gamma+TNF-alpha-induced NFkappaB DNA binding. The lack of influence of hGH on cytokine-mediated activation of STAT1 and NFkappaB is in accordance with the finding that hGH had only a minor effect on cytokine-induced inducible nitric oxide synthase (iNOS) gene expression and in fact augmented the IL-1beta-stimulated nitric oxide production. As the anti-apoptotic Bcl-xL gene has been shown to harbour a STAT5-binding element we measured the expression of Bcl-xL as well as the pro-apoptotic Bax. We found that hGH increased the Bcl-xL/Bax ratio both in the absence and in the presence of cytotoxic cytokines. In conclusion, these results suggested that GH and PRL protect beta-cells against cytotoxic cytokines via STAT5-dependent mechanisms distal to iNOS activation possibly at the level of Bcl-xL.
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PMID:STAT5 activation by human GH protects insulin-producing cells against interleukin-1beta, interferon-gamma and tumour necrosis factor-alpha-induced apoptosis independent of nitric oxide production. 1621 38

Islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) is recognized as a major autoantigen for autoimmune type 1 diabetes (T1D) in the NOD mouse model. This study was undertaken to examine CD4+ T cell responses toward IGRP in human subjects. The tetramer-guided epitope mapping approach was used to identify IGRP-specific CD4+ T cell epitopes. IGRP(23-35) and IGRP(247-259) were identified as DRA1*0101/DRB1*0401-restricted epitopes. IGRP(13-25) and IGRP(226-238) were identified as DRA1*0101/DRB1*0301-restricted epitopes. IGRP-specific tetramers were used to evaluate the prevalence of IGRP-reactive T cells in healthy and T1D subjects. More than 80% of subjects with either DRB1*0401 or DRB1*0301 haplotype have IGRP-specific CD4+ T cell responses for at least one IGRP epitope. IGRP-specific T cells from both healthy and T1D groups produce both gamma-IFN and IL-10. DRA1*0101/DRB1*0401 IGRP(247-259)-restricted T cells also show cross-reactivity to an epitope derived from liver/kidney glucose-6-phosphatase. The detection of IGRP-reactive T cells in both type 1 diabetic subjects and healthy subjects and recent reports of other autoreactive T cells detected in healthy subjects underscore the prevalence of potentially autoreactive T cells in the peripheral immune system of the general population.
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PMID:Islet-specific glucose-6-phosphatase catalytic subunit-related protein-reactive CD4+ T cells in human subjects. 1649 34

High-resolution mapping and identification of the genes responsible for type 1 diabetes (T1D) has proved difficult because of the multigenic etiology and low penetrance of the disease phenotype in linkage studies. Mouse congenic strains have been useful in refining Idd susceptibility loci in the NOD mouse model and providing a framework for identification of genes underlying complex autoimmune syndromes. Previously, we used NOD and a nonobese diabetes-resistant strain to map the susceptibility to T1D to the Idd4 locus on chromosome 11. Here, we report high-resolution mapping of this locus to 1.4 megabases. The NOD Idd4 locus was fully sequenced, permitting a detailed comparison with C57BL/6 and DBA/2J strains, the progenitors of T1D resistance alleles found in the nonobese diabetes-resistant strain. Gene expression arrays and quantitative real-time PCR were used to prioritize Idd4 candidate genes by comparing macrophages/dendritic cells from congenic strains where allelic variation was confined to the Idd4 interval. The differentially expressed genes either were mapped to Idd4 or were components of the IFN response pathway regulated in trans by Idd4. Reflecting central roles of Idd4 genes in Ag presentation, arachidonic acid metabolism and inflammation, phagocytosis, and lymphocyte trafficking, our combined analyses identified Alox15, Alox12e, Psmb6, Pld2, and Cxcl16 as excellent candidate genes for the effects of the Idd4 locus.
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PMID:Molecular genetic analysis of the Idd4 locus implicates the IFN response in type 1 diabetes susceptibility in nonobese diabetic mice. 1649 56

Characterization of dendritic cells (DC) in human diabetes has been restricted to monocyte-derived DC in type 1 diabetes, whose physiological relevance to endogenous DC is uncertain. Here, we provide the first report characterizing the phenotype and function of endogenous DC subsets in type 1 and type 2 diabetes. We show that DC subsets in each diabetic group exhibit normal properties concerning frequency and activation state, as determined using 4-color flow cytometry of whole blood cells. DC maturation is also intact as confirmed by their efficacious ability to stimulate T cell proliferation in an allogeneic MLR assay. Yet we found that DC are poor producers of IFN-alpha (P < 0.05) in human diabetes. IFN-alpha is a potent antiviral agent and therefore its reduced levels may interfere with T cell-mediated immune responses leading to increased susceptibility and persistence of infections in persons with diabetes.
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PMID:Reduced IFN-alpha secretion by blood dendritic cells in human diabetes. 1685 98

Increasing attention is drawn to the contributions of abnormalities in both innate and acquired immune responses to the pathogenesis of autoimmune diseases, such as type 1 diabetes (T1D). Dendritic cells (DC) are critical immune cells linking innate and acquired immune responses and previous studies in NOD mice suggest abnormalities in these cells. To address DC dysregulation we examined kinetic global gene expression in NOD and B6 GM-CSF/IL-4-induced bone marrow-derived DC following lipopolysaccharide (LPS)-stimulation. We identified expression differences in over 300 genes including a cluster of 16 interferon (IFN-alpha/beta) target genes overexpressed in NOD DC. Mechanistically, heightened IFN-alpha/beta responses were not due to increased production of this cytokine, IFN-gamma priming or increased Syk kinase activity. We found, however, heightened responses to IFN-alpha/beta in NOD versus B6 as demonstrated by increased type 1 IFN target gene expression, for example, IRF-7, in NOD DC and macrophages. Analysis of multiple congenic strains demonstrated that the Idd5 susceptibility region largely governed heightened IFN-alpha responses. Of interest, heightened IFN-alpha/beta response in NOD mice was not confined to hematopoietic cells but was also seen in the pancreas and beta cells. Compounding the IFN-alpha response defect, NOD mice harbor significantly more PDC in spleen in comparison to B6 and produce four- to sixfold more IFN-alpha when stimulated with CpG. Finally, treatment of NOD mice with IFN-alpha inducing agents, for example, high-dose poly I:C accelerates diabetes in both female and male mice. The abnormalities in the IFN-alpha/beta axis appear to play a significant role in T1D pathogenesis.
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PMID:Heightened interferon-alpha/beta response causes myeloid cell dysfunction and promotes T1D pathogenesis in NOD mice. 1713 May 37

Enteroviruses, such as the coxsackievirus (CV) group, have been linked to the induction of inflammatory and autoimmune diseases. Virus tropism and tissue access are modulated by endothelial cells. To examine the susceptibility of microvascular endothelial cells (MECs) derived from pancreatic islets to infection with CV group B (CVB), purified cultured human islet MECs were infected with CVB-4 strain, and the immunological phenotype of the infected cells was analyzed. CVB-4 persistently infected the islet MECs, which expressed the CV receptors human coxsackievirus and adenovirus receptor (HCAR) and decay accelerating factor (DAF) and maintained EC characteristics, without overt cytopathic effects. CVB-4 infection transiently up-regulated expression of the adhesion molecules ICAM-1 and VCAM-1 and increased production of the proinflammatory cytokines IL-1beta and IL-6, and chemokines IL-8 and lymphotactin, as well as IFN-alpha. Mononuclear cell adhesion to CVB infected monolayers was increased, compared to uninfected monolayers. Moreover, infection up-regulated the viral receptors HCAR and DAF and coreceptor alpha(v)beta3 integrin on islet MECs, while down-regulating expression of HCAR on human aortic endothelial cells, indicating potential tissue-specific influence on the pathological outcome of infection. These results provide evidence that islet MECs are natural targets and reservoirs for persistent CVB infection resulting in acute endothelial cell activation by virus, which may contribute to selective recruitment of subsets of leukocytes during inflammatory immune responses, such as insulitis in type 1 diabetes.
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PMID:Human pancreatic islet endothelial cells express coxsackievirus and adenovirus receptor and are activated by coxsackie B virus infection. 1749 92

Type 1 diabetes mellitus can result from the specific destruction of pancreatic beta cells by autoreactive T cells. As shown here, experimental autoimmune diabetes (EAD) is efficiently induced in RIP-B7.1 mice by preproinsulin (ppins)-encoding DNA vaccines. EAD develops in RIP-B7.1 mice within 3-4 wk after a single immunization with ppins-encoding plasmid DNA. RIP-B7.1 mice develop insulitis, insulin deficiency and hyperglycemia after vaccination with plasmids encoding murine ppins-I or murine ppins-II or human hu-ppins. EAD induction critically depends on CD8 T cells and is independent of CD4 T cells. To be diabetogenic, ppins-specific CD8 T cells had to express IFN-gamma. Neither expression of perforin nor signaling through the type I IFN receptor is an essential component of this pathogenic CD8 T cell phenotype. Using plasmids encoding truncated ppins variants, we show that EAD is only induced by DNA vaccines encoding the insulin A-chain. Diabetogenic CD8 T cells specifically recognize the Kb-restricted A12-21 epitope of the insulin A-chain. The RIP-B7.1 model hence represents an attractive model for the characterization of cellular and molecular events involved in the CD8 T cell-mediated immune pathogenesis of diabetes.
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PMID:The diabetogenic, insulin-specific CD8 T cell response primed in the experimental autoimmune diabetes model in RIP-B7.1 mice. 1761 84


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