Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In earlier studies it has been shown that prolactin (PRL) is a stimulating factor for the immune system, and it has been suggested that PRL might antagonize immunosuppressive effects of glucocorticoids. PRL has been reported to affect the cytokine secretion pattern, by elevating cytokine gene expression in macrophages, after the onset of sepsis. It also promotes the antibody response in mice where it increases the production of interferon-gamma (IFN-gamma) and inhibits interleukin-1 (IL-1) production. Due to these properties, PRL might influence the development of autoimmune type 1 diabetes. The aim of the present study was to examine the effects of two drugs; PRL and bromocriptine (BC) in vivo on the development of hyperglycemia and pancreatic insulitis in mice treated with multiple doses of streptozotocin (STZ) (40 mg/kg body weight, i.p.). The dopaminergic agonist BC is known to inhibit PRL secretion. In another set of experiments, the direct effects of PRL on the function of pancreatic islets exposed to STZ in vitro were studied. Mice treated with STZ became gradually hyperglycemic, and concomitant treatment with PRL (4 mg/kg body weight) for 21 days significantly reduced the elevation in blood glucose levels from day 10 onwards (P<0.05). Morphologic examinations of the pancreas on day 21 of mice receiving STZ injections revealed a marked insulitis, but only moderate insulitis in the STZ treated animals given PRL. BC administration (10 mg/kg body weight) in combination with STZ did not significantly affect the elevation in blood glucose levels or the insulitis. PRL or BC administration alone did not change the serum glucose concentration. This study indicates that PRL may affect hyperglycemia in the early phase of autoimmune diabetes. We suggest that it might be due to counteraction of autoimmune immunologic mechanisms and/or enhancement of beta-cell regeneration.
 ...
PMID:Prolactin protects against diabetes induced by multiple low doses of streptozotocin in mice. 1055 72

We evaluated the effects of recombinant human (rh) interleukin (IL)-11 on the development of spontaneous and cyclophosphamide-induced diabetes in female NOD mice. Prolonged treatment with rhIL-11 10 microg i.p. five consecutive times a week between the 4th and 22nd weeks of age significantly suppressed both development and cumulative incidence of type 1 diabetes. Disease protection was transient because most of the animals developed type 1 diabetes within 3 months of treatment withdrawal. In contrast, rhIL-11 failed to prevent type 1 diabetes when administered for the first time to euglycemic 18-week-old NOD mice. Most likely, this discrepancy was not due to age-dependent differences in the immunological responses of NOD mice to rhIL-11 because staphylococcus aureus enterotoxin B-induced tumor necrosis factor (TNF) and IL-12 production were equally suppressed by rhIL-11 in 12- and 25-week-old NOD mice. Relative to controls, NOD mice pretreated with rhIL-11 also showed significantly diminished blood levels of TNF, interferon-gamma, and IL-12 induced by anti-CD3 antibody and/or lipopolysaccharide. The results demonstrate that rhIL-11 has powerful anti-inflammatory effects that are capable of down-regulating early immunodiabetogenic pathways in NOD mice.
 ...
PMID:Early prophylaxis with recombinant human interleukin-11 prevents spontaneous diabetes in NOD mice. 1058 Apr 21

Reactive oxygen species play an important role in the cytotoxic effect of inflammatory cytokines on pancreatic beta-cells in type 1 diabetes mellitus. The antioxidant enzyme manganese superoxide dismutase (MnSOD) is part of the cellular defenses against these deleterious radicals. MnSOD gene expression is induced by cytokines in insulin-producing cells, but the transcriptional regulation of MnSOD expression in these cells is not well understood. In this report, we investigated the transcriptional regulation by cytokines of the rat MnSOD gene in insulin-producing cells. By transient transfections with promoter-luciferase reporter constructs, we identified two interleukin (IL)-1beta-responsive elements, conferring each an additive 3-fold IL-1beta-induced transcriptional activity. The first is located in the promoter region, whereas the second is located in the second intron of the MnSOD gene. Interestingly, the intronic element is required for interferon-gamma-induced potentiation. Site-directed mutagenesis and band-shift assays showed that an NF-kappaB binding site in each region is necessary, but not sufficient, for transcriptional induction by IL-1beta. Our results suggest that NF-kappaB may cooperate with CCAAT/enhancer-binding protein factors in the promoter region and with octamer and Ets factors in the intronic region.
 ...
PMID:NF-kappaB is required for cytokine-induced manganese superoxide dismutase expression in insulin-producing cells. 1061 34

Recent studies have shown that loci outside the HLA region are involved in determining susceptibility to type 1 diabetes. Polymorphisms in the coding and noncoding regions of the genes encoding cytokines may be involved in modulating the immune response to self and nonself antigens. There is increasing evidence that an imbalance and disruption of the Thl and Th2 T cell subsets play a key role in the development of experimental and clinical type 1 diabetes. The aim of this study was to investigate the frequency of a CA dinucleotide repeat polymorphism in the interferon-gamma (IFN-gamma) gene (IFNG) and a C(-590)T polymorphism of the interleukin-4 (IL-4) gene in 236 Caucasoid patients with type 1 diabetes. There was a highly significant increase in the 3/3 IFNG genotype in the patients compared with normal healthy controls (34.3% vs. 13.5%, p<0.0001) as well as a significant increase in allele 3 of the IFNG locus in the patients compared with controls (51.9% vs. 31.7%, p<0.00001). In contrast, no significant differences were found in the frequency of the C(-590)T IL-4 polymorphism between patients and controls. These results suggest that polymorphisms of the IFNG gene may modify the function of this proinflammatory mediator and the response to pancreatic islet beta cells.
 ...
PMID:A CA repeat polymorphism of the IFN-gamma gene is associated with susceptibility to type 1 diabetes. 1071 54

To evaluate the effect of antigen-pulsed dendritic cell (DC) transfer on the development of diabetes, 5-week-old female NOD mice received a single iv injection of splenic syngeneic DC from euglycemic NOD mice pulsed in vitro with human y globulin (HGG). Eleven of 12 mice were protected from the development of diabetes up to the age of 25 weeks, and the insulitis score was significantly reduced. In contrast, NOD mice receiving unpulsed splenic DCs showed histological signs of insulitis and course of type 1 diabetes similar to untreated NOD mice. Treatment with HGG-pulsed DC was associated with profound modifications of cytokine secretory capacities within the islets. Thus, supernatants of islets from these mice contained increased levels of interleukin (IL)-4, IL-10, and, to a lesser extent, interferon-gamma and diminished levels of tumor necrosis factor-a compared with controls. Because exogenous IL-4 and IL-10 exert antidiabetogenic effect in NOD mice and early blockade of endogenous tumor necrosis factor-alpha prevents NOD mouse diabetes, these phenomena may be causally related to the antidiabetogenic effect of HGG-pulsed DC treatment.
 ...
PMID:Prevention of spontaneous autoimmune diabetes in NOD mice by transferring in vitro antigen-pulsed syngeneic dendritic cells. 1074 56

Cytokines may contribute to beta-cell apoptosis in the early stages of type 1 diabetes mellitus. It has been reported recently that interleukin-1 beta (IL-1 beta) induces activation of the mitogen-activated protein kinases (MAPK) p38 and ERK1/2 in neonatal rat islets. Since these kinases may participate in cytokine-induced apoptosis, we evaluated whether cytokines induce activation of MAPKs in FACS-purified primary rat beta-cells, and whether blockers of p38 and/or ERK1/2 prevent beta-cell death. IL-1 beta, but not interferon-gamma (IFN-gamma), caused phosphorylation of the substrates Elk-1, ATF-2 and hsp25, and the phosphorylation of both Elk-1 and hsp25 were decreased by the p38 blocker SB203580 (p38i) and the MAPK/ERK blocker PD 098059 (MEKi). When added together, p38i and MEKi decreased IL-1 beta-induced nitrite production over 24 hours by 60%, but did not affect IL-1 beta-induced manganese superoxide dismutase (MnSOD) mRNA expression. To test the effects of MAPK inhibitors on beta-cell death by necrosis or apoptosis, these cells were exposed for 6 or 9 days to IL-1 beta + IFN-gamma. This treatment induced cell death, mostly by apoptosis. The MEKi, but not the p38i, significantly decreased cytokine-induced apoptosis, thus decreasing the total number of dead cells. This protection was only partial, suggesting that ERK1/2 activation is not the only mechanism by which cytokines induce beta-cell apoptosis. We conclude that IL-1 beta induces activation of both p38 and ERK1/2, and that ERK1/2 contributes to the pro-apoptotic effects of the cytokine in primary beta-cells.
 ...
PMID:Activation of extracellular signal-regulated kinase (ERK)1/2 contributes to cytokine-induced apoptosis in purified rat pancreatic beta-cells. 1090 6

Enteroviruses are proposed as initiating factors in the etiology of Type 1 diabetes mellitus (Type 1 DM). Molecular mimicry between the autoantigen glutamic acid decarboxylase 65 (GAD65) and the coxsackievirus B4 (CVB4) nonstructural protein P2C is frequently cited as a mechanism by which this virus triggers the disease, but little is known about the immunogenicity of this viral protein in humans, mainly due to the problem of obtaining highly pure preparations of P2C. We generated large amounts of highly pure, soluble P2C protein, coupled to the fusion partner maltose binding protein (MBP-P2C) using the PMAL-c2 bacterial expression plasmid and a two-step purification system comprising amylose resin and ion exchange. Using purified viral protein we show that specific T-cell responses against P2C are detected in the blood of healthy donors and Type 1 DM patients. Proliferation responses to P2C were detected only in subjects also demonstrating T-cell proliferation to CVB4 Vero cell lysates. However, in additional cases T-cell responses to P2C were detectable through the release of interferon-gamma or interleukin-4 in individuals who did not make proliferative responses. Taken together, our data show that the P2C nonstructural protein of CVB4 is targeted by T cells during the antiviral immune response and may trigger the production of T helper 1 and T helper 2 cytokines. The availability of pure, immunogenic P2C should allow the putative role of antiviral responses in the development of autoimmune diabetes to be investigated.
 ...
PMID:T-Cell reactivity to the P2C nonstructural protein of a diabetogenic strain of coxsackievirus B4. 1093 88

Type 1 diabetes is an autoimmune disease leading to extensive destruction of the pancreatic beta-cells. Our research focusses on the role of beta-cells during the course of the disease, aiming at finding novel strategies to enhance beta-cell resistance against the cytotoxic damage inflicted by the immune system. Special attention has been paid to the possibility that cytokines released by the immune cells infiltrating the pancreatic islets can directly suppress and kill beta-cells. Certain cytokines (interleukin-1beta, tumor necrosis factor-alpha and interferon-gamma) either alone or in combination, are able to activate signal transduction pathways in beta-cells leading to transcription factor activation and de novo gene expression. In this context, it has been found that induction of inducible nitric oxide synthase mediates an elevated production of nitric oxide, which impairs mitochondrial function and causes DNA damage eventually leading to apoptosis and necrosis. However, other induced proteins SUCH AS heat shock protein 70 and superoxide dismutase may reflect a defense reaction elicited in the beta-cells by the cytokines. Our strategy is to further seek for proteins involved in both destruction and protection of beta-cells. Based on this knowledge, we plan to apply gene therapeutic approaches to increase expression of protective genes in beta-cells. If this is feasible we will then evaluate the function and survival of such modified beta-cells in animal models of type 1 diabetes such as the NOD mouse. The long-term goal for this research line is to find novel approaches to influence beta-cell resistance in humans at risk of developing type 1 diabetes.
 ...
PMID:Novel experimental strategies to prevent the development of type 1 diabetes mellitus. 1109 3

In addition to inhibiting matrix metalloproteinase-2 and matrix metalloproteinase-9 activity, recent studies suggest that tissue inhibitor of metalloproteinase (TIMP)-1 may inhibit apoptosis in various cell lines. To address this question in pancreatic islets and beta-cells, we treated rat pancreatic islets and INS-1 cells with a high-dose combination of the cytokines interleukin (IL)-1beta, tumor necrosis factor-alpha, and interferon-gamma with or without the addition of TIMP-1 and TIMP-2 protein. Using flow cytometry, we quantitated DNA fragmentation to assess cellular apoptosis and confirmed these observations with DNA laddering experiments. Next, we transfected the mouse TIMP-1 gene into INS-1 cells and performed Western immunoblotting to demonstrate expression of TIMP-1 protein. We treated TIMP-1-expressing INS-1 cells with high-dose cytokines and again used flow cytometry to assess DNA fragmentation. We also evaluated the effect of TIMP-1 on IL-1beta-induced inhibition of glucose-stimulated insulin secretion (GSIS) in freshly isolated rat pancreatic islets. Finally, we evaluated the effect of TIMP-1 on inducible nitric oxide synthase (iNOS) gene expression and nuclear factor (NF)-kappaB activity in INS-1 cells stimulated with high-dose cytokines. TIMP-1 but not TIMP-2 prevented cytokine-induced apoptosis and cytokine-mediated inhibition of GSIS in rat islets and beta-cells. TIMP-1 mediated these effects by inhibiting cytokine activation of NF-kappaB, but it did not affect nitric oxide production or iNOS gene expression. Therefore, TIMP-1 may be an ideal gene to prevent cytokine-mediated beta-cell destruction and dysfunction in models of type 1 diabetes and islet transplantation rejection.
 ...
PMID:Tissue inhibitor of metalloproteinase-1 prevents cytokine-mediated dysfunction and cytotoxicity in pancreatic islets and beta-cells. 1133 7

Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by progressive destruction of insulin-producing pancreatic beta-cells. Both viral infections and the cytokines interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) have been suggested as potential mediators of beta-cell death in early T1DM. We presently investigated whether the viral replicative intermediate double stranded RNA [here used as synthetic polyinosinic-polycytidylic acid (PIC)] modifies the effects of IL-1beta and IFN-gamma on gene expression and viability of rat pancreatic beta-cells. For this purpose, fluorescence-activated cell sorting-purified rat beta-cells were exposed for 6-16 h (study of gene expression by RT-PCR) or 6-9 days (study of viability by nuclear dyes) to PIC and/or IL-1beta and IFN-gamma. PIC increased the expression of Fas and Mn superoxide dismutase messenger RNAs by 5- to 10-fold. IL-1beta and a combination of PIC and IFN-gamma (but not PIC or IFN-gamma alone) induced expression of inducible nitric oxide (NO) synthase (iNOS) and consequent NO production. Induction of iNOS expression by PIC and IFN-gamma requires nuclear factor-kappaB activation, as suggested by transfection experiments with iNOS promoter-luciferase reporter constructs into primary beta-cells. Combinations of IL-1beta plus IFN-gamma, PIC plus IFN-gamma, or PIC plus IL-1beta induced a 2- to 3-fold increase in the number of apoptotic beta-cells. Blocking of iNOS activity significantly decreased PIC- plus IL-1beta-induced, but not PIC- plus IFN-gamma-induced, apoptosis. In conclusion, PIC alone or in combination with cytokines modifies the expression of several genes in pancreatic beta-cells. Two of these genes, Fas and iNOS, may contribute to beta-cell death. The transcription factor nuclear factor-kappaB is required for PIC-induced iNOS expression. PIC has an additive effect on cytokine-induced beta-cell death by both NO-dependent (in the case of IL-1beta) and NO-independent (in the case of IFN-gamma) mechanisms. These findings suggest that viral intermediates in synergism with local cytokine production may play an important role in beta-cell apoptosis in early T1DM.
 ...
PMID:Double-stranded ribonucleic acid (RNA) induces beta-cell Fas messenger RNA expression and increases cytokine-induced beta-cell apoptosis. 1135 9


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>