Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0011849 (diabetes)
277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previously, we reported that T cell hyporesponsiveness induced by TCR ligation is causal to autoimmune diabetes in NOD mice. Neonatal CD28 co-stimulation reverses T cell hyporesponsiveness and protects NOD mice from diabetes by an IL-4-mediated mechanism, indicating that a deficiency in TCR signaling may be overcome by CD28/B7-2 co-stimulation in NOD T cells. To investigate which co-stimulation-induced signaling events mediate this protection, we analyzed the activity of Ras, Rac-1, mitogen-activated protein kinases (MAPK) and several transcription factors in TCR-activated NOD T cells in the presence or absence of CD28 co-stimulation. We show that CD28 co-stimulation restores normal TCR-induced activation of Rac-1 and p38 MAPK in NOD T cells. Deficiencies in TCR-induced nuclear expression of activating protein (AP)-1 binding proteins as well as activation of AP-1 and NF-AT in the IL-2 and IL-4 P1 promoters are also corrected by CD28 co-stimulation. Thus, CD28 co-stimulation reverses NOD T cell hyporesponsiveness by restoring TCR signaling leading to the activation of AP-1 and NF-AT during IL-2 and IL-4 gene transcription. Our findings provide additional evidence that CD28 co-stimulation amplifies signals delivered by the TCR and further explain the mechanism by which CD28 co-stimulation may protect against autoimmune diabetes.
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PMID:CD28 co-stimulation restores T cell responsiveness in NOD mice by overcoming deficiencies in Rac-1/p38 mitogen-activated protein kinase signaling and IL-2 and IL-4 gene transcription. 1122 7

The onset of autoimmune diabetes is related to defective immune regulation. Recent studies have shown that NK T cells are deficient in number and function in both diabetic patients and nonobese diabetic (NOD) mice. NK T cells, which are CD1d restricted, express a TCR with an invariant V alpha 14-J alpha 281 chain and rapidly produce large amounts of cytokines. V alpha 14-J alpha 281 transgenic NOD mice have increased numbers of NK T cells and are protected against diabetes onset. In this study we analyzed where and how NK T cells interfere with the development of the anti-islet autoimmune response. NK T cells, which are usually rare in lymph nodes, are abundant in pancreatic lymph nodes and are also present in islets. IL-4 mRNA levels are increased and IFN-gamma mRNA levels decreased in islets from diabetes-free V alpha 14-J alpha 281 transgenic NOD mice; the IgG1/IgG2c ratio of autoantibodies against glutamic acid decarboxylase is also increased in these mice. Treatment with IL-12 (a pro-Th1 cytokine) or anti-IL-4 Ab abolishes the diabetes protection in V alpha 14-J alpha 281 NOD mice. The protection from diabetes conferred by NK T cells is thus associated with a Th2 shift within islets directed against autoantigen such as glutamic acid decarboxylase. Our findings also demonstrate the key role of IL-4.
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PMID:NK T cell-induced protection against diabetes in V alpha 14-J alpha 281 transgenic nonobese diabetic mice is associated with a Th2 shift circumscribed regionally to the islets and functionally to islet autoantigen. 1123 16

The induction of immunological self-tolerance begins in the thymus during fetal life. The random recombination of gene segments coding for TCR is followed by the negative selection of T cells bearing a TCR directed against self-antigens presented by thymic MHC. Insulin-like growth factor type 2 (IGF-2) is the dominant gene of the insulin family that is transcribed and translated in the thymus of different species. Contrary to the other members of the insulin gene family, IGF-2 gene (IGF2) is not transcribed in the thymus of diabetes-prone BB rats. The absence of thymic IGF2 expression is associated with the diabetogenic autoimmune process in BB rats. This defect could not only contribute to the lymphopenia of BB rats, but also to the absence of central self-tolerance of the insulin family in this animal.
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PMID:[Role of the thymus in the pathophysiology of autoimmune diabetes type 1]. 1130 59

The prevalence of coeliac disease (CD) in the adult population is unknown because silent and latent stages do exist. Type 1 diabetes mellitus may be associated with CD because of common genetic background and/or shared pathogenetic mechanisms. We investigated 74 adults with type 1 diabetes (32+/-11 yr, disease duration 13+/-9 yr), 69 parents of diabetic probands (56+/-10 yr), 59 siblings (30+/-11 yr) and 50 healthy controls (35+/-10 yr) for the presence of circulating islet cell antibodies (ICA), anti-glutamic acid decarboxylase antibodies (GADA65), anti-gliadin immunoglobulins A and G (IgA- and IgG-AGA). All patients with raised AGA, performed also IgA anti-endomysium antibody (EmA) indirect immunofluorescence assay. Samples were positive for ICA in 19 diabetics (26%), 4 parents (6%), 4 siblings (7%), 0 controls (p<0.001); for GADA in 34 diabetics (46%), 4 parents (6%), 1 sibling (2%), 0 controls (p<0.001). Twenty-five diabetic patients (34%), 10 parents (14%), 5 siblings (8%), 3 controls (6%) (p<0.001) had raised IgA-AGA (>4.4 mg/l). Four diabetic patients (5%), 5 parents (7%), 0 siblings (0%), 4 controls (8%) had raised IgG-AGA (>18 mg/l). Both IgA- and IgG-AGA were detected in 1 diabetic and 2 parents. The prevalence of ICA, GADA, and IgA-AGA positivity in Type 1 diabetes patients was significantly higher than in controls (p<0.001). Finally, 50 AGA-positive subjects performed EmA test: only 2 of them resulted EmA-positive, a diabetic patient and a sibling. The patient with Type 1 diabetes had a small-bowel biopsy specimen consistent with CD and, as sole evidence of malabsorption, sideropenic anaemia. EmA-positive sibling also showed severe iron deficiency, yet refused endoscopy. We conclude that: 1) CD cannot be diagnosed on the basis of associated IgA- and IgG-AGA alone. Nevertheless, detection of such antibodies is useful, in combination with EmA, in screening for endoscopic biopsy; 2) too high rate of detection of IgA-AGA in Type 1 diabetic patients in comparison with other groups excludes a false positivity of the test itself, while suggests a pathogenetic association of both immunological disorders, perhaps related to abnormal gammadelta TCR-bearing intraepithelial lymphocytes.
Diabetes Nutr Metab 2001 Feb
PMID:Screening for coeliac disease in families of adults with Type 1 diabetes based on serological markers. 1134 64

A subset of CD161 (NK1) T cells express an invariant Valpha14Jalpha281 TCR-alpha chain (Valpha(invt) T cells) and produce Th2 and Th1 cytokines rapidly in response to CD1d, but their physiological function(s) remain unclear. We have found that CD1d-reactive T cells mediate to resistance against the acute, cytopathic virus diabetogenic encephalomyocarditis virus (EMCV-D) in relatively Th1-biased, C57BL/6-based backgrounds. We show now that these results generalize to Th2-biased, hypersensitive BALB/c mice. CD1d-KO BALB/c mice were more susceptible to EMCV-D. Furthermore, alpha-galactosylceramide (alpha-GalCer), a CD1d-presented lipid antigen that specifically activates Valpha(invt) T cells, protected wild-type (WT) mice against EMCV-D-induced encephalitis, myocarditis, and diabetes. In contrast, neither CD1d-KO nor Jalpha281-KO mice were protected by alpha-GALCER: Finally, disease in Jalpha281-KO mice was comparable to WT, indicating for the first time equivalent roles for CD1d-reactive Valpha(invt) and noninvariant T cells in resistance to acute viral infection. A model for how CD1d-reactive T cells can initiate immune responses, which synthesizes current results, is presented.
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PMID:CD1d-reactive T-cell activation leads to amelioration of disease caused by diabetogenic encephalomyocarditis virus. 1135 78

Defects in NK and NKT cell activities have been implicated in the etiology of type 1 (autoimmune) diabetes in NOD mice on the basis of experiments performed using surrogate phenotypes for the identification of these lymphocyte subsets. Here, we have generated a congenic line of NOD mice (NOD.b-Nkrp1(b)) which express the allelic NK1.1 marker, enabling the direct study of NK and NKT cells in NOD mice. Major deficiencies in both populations were identified when NOD.b-Nkrp1(b) mice were compared with C57BL/6 and BALB.B6-Cmv1(r) mice by flow cytometry. The decrease in numbers of peripheral NK cells was associated with an increase in their numbers in the bone marrow, suggesting that a defect in NK cell export may be involved. In contrast, the most severe deficiency of NKT cells found was in the thymus, indicating that defects in thymic production were probably responsible. The deficiencies in NK cell activity in NOD mice could only partly be accounted for by the reduced numbers of NK cells, and fewer NKT cells from NOD mice produced IL-4 following stimulation, suggesting that NK and NKT cells from NOD mice shared functional deficiencies in addition to their numerical deficiencies. Despite the relative lack of IL-4 production by NOD NKT cells, adoptive transfer of alpha beta TCR(+)NK1.1(+) syngeneic NKT cells into 3-week-old NOD recipients successfully prevented the onset of spontaneous diabetes. As both NK and NKT cells play roles in regulating immune responses, we postulate that the synergistic defects reported here contribute to the susceptibility of NOD mice to autoimmune disease.
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PMID:Cytometric and functional analyses of NK and NKT cell deficiencies in NOD mice. 1143 19

To further define the molecular basis of tolerance to a peripherally expressed antigen we have correlated differences in functional capacity with biochemical events in hemagglutinin (HA)-specific cytotoxic T lymphocyte (CTL) clones derived either from a conventional B10.D2 mouse that is not tolerant to HA (D2 Clone 6) or from an InsHA mouse that is tolerant to HA (InsHA Clone 12). D2 Clone 6, but not InsHA Clone 12, triggers diabetes following in vivo transfer into irradiated InsHA hosts. This diabetogenic clone shows complete and sustained phosphorylation of TCR zeta chain and ZAP-70 following stimulation with HA-pulsed antigen-presenting cells. In contrast, InsHA Clone 12 showed only partial phosphorylation of TCR zeta and no phosphorylation of ZAP-70. There was no defect in activation or recruitment of Lck to the TCR complex in both the clones following stimulation with the cognate antigen. This deficiency in the proximal signaling in the InsHA Clone 12 could be overcome by increasing the strength of signal through the CD3-TCR complex, indicating that the signaling machinery of InsHA Clone 12 was functional. These data demonstrate that the HA-responsive CD8(+) T cells that can be retrieved from InsHA mice after tolerance induction respond to HA as a partial agonist/antagonist.
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PMID:Altered functional and biochemical response by CD8+ T cells that remain after tolerance. 1147 Jul 78

BDC2.5/nonobese diabetic (NOD) transgenic mice express a TCR from a diabetogenic T cell clone yet do not spontaneously develop diabetes at high incidence. Evidence exists showing that in the absence of endogenous TCR alpha-chain rearrangements this transgenic mouse spontaneously develops diabetes and that CTLA-4 negatively regulates diabetes onset. This strongly suggests that onset of diabetes in BDC2.5/NOD mice is governed by T cell regulation. We addressed the mechanism of immune regulation in BDC2.5/NOD mice. We find that activated spleen cells from young, but not old, BDC2.5/NOD mice are able to transfer diabetes to NOD-scid recipients. We have used anti-IL-10R to show that the failure of splenocytes from older mice to transfer diabetes is due to dominant regulation. We furthermore found that diabetes developed following anti-IL-10R treatment of 6-wk old BDC2.5/NOD mice indicating that endogenous IL-10 plays a key role in the regulation of diabetes onset in this transgenic mouse.
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PMID:Cutting edge: interactions through the IL-10 receptor regulate autoimmune diabetes. 1171 66

Type 1 diabetes in nonobese diabetic (NOD) mice is characterized by the infiltration of T and B cells into pancreatic islets. T cells bearing the TCR Vbeta3 chain are disproportionately represented in the earliest stages of islet infiltration (insulitis) despite clonal deletion of most Vbeta3(+) immature thymocytes by the mammary tumor virus-3 (Mtv-3) superantigen (SAg). In this report we showed that a high frequency of NOD Vbeta3(+) T cells that escape deletion are activated in vivo and that this phenotype is linked to the Mtv-3 locus. One potential mechanism of SAg presentation to peripheral T cells is by activated B cells. Consistent with this idea, we found that NOD mice harbor a significantly higher frequency of activated B cells than nondiabetes-prone strains. These activated NOD B cells expressed cell surface molecules consistent with APC function. At the molecular level, the IgH repertoire of activated B cells in NOD mice was equivalent to resting B cells, suggesting a polyclonal response in vivo. Genetic analysis of the activated B cell phenotype showed linkage to Idd1, the NOD MHC haplotype (H-2(g7)). Finally, Vbeta3(+) thymocyte deletion and peripheral T cell activation did not require B cells, suggesting that other APC populations are sufficient to generate both Mtv-3-linked phenotypes. These data provide insight into the genetic regulation of NOD autoreactive lymphocyte activation that may contribute to failure of peripheral tolerance and the pathogenesis of type I diabetes.
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PMID:Genetic control of T and B lymphocyte activation in nonobese diabetic mice. 1173 40

Administration of anti-L-selectin (CD62L) mAb to neonatal nonobese diabetic (NOD) mice mediates long term protection against the development of insulitis and overt diabetes. These results suggested that CD62L has a key role in the general function of beta cell-specific T cells. To further examine the role of CD62L in the development of type 1 diabetes, NOD mice lacking CD62L were established. The onset and frequency of overt diabetes were equivalent among CD62L(+/+), CD62L(+/-), and CD62L(-/-) NOD littermates. Furthermore, patterns of T cell activation, migration, and beta cell-specific reactivity were similar in NOD mice of all three genotypes. Adoptive transfer experiments with CD62L(-/-) CD4(+) T cells prepared from BDC2.5 TCR transgenic mice revealed no apparent defects in migration to pancreatic lymph nodes, proliferation in response to beta cell Ag, or induction of diabetes in NOD.scid recipients. In conclusion, CD62L expression is not essential for the development of type 1 diabetes in NOD mice.
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PMID:L-selectin is not required for T cell-mediated autoimmune diabetes. 1188 30


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