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

Cytokine-induced beta-cell death is an important event in the pathogenesis of type 1 diabetes. The transcription factor nuclear factor-kappaB (NF-kappaB) is activated by interleukin-1beta (IL-1beta), and its activity promotes the expression of several beta-cell genes, including pro- and anti-apoptotic genes. To elucidate the role of cytokine (IL-1beta + gamma-interferon [IFN-gamma])-induced expression of NF-kappaB in beta-cell apoptosis, rat beta-cells were infected with the recombinant adenovirus AdIkappaB((SA)2), which contained a nondegradable mutant form of inhibitory kappaB (IkappaB((SA)2), with S32A and S36A) that locks NF-kappaB in a cytosolic protein complex, preventing its nuclear action. Expression of IkappaB((SA)2) inhibited cytokine-stimulated nuclear translocation and DNA-binding of NF-kappaB. Cytokine-induced gene expression of several NF-kappaB targets, namely inducible nitric oxide synthase, Fas, and manganese superoxide dismutase, was prevented by AdIkappaB((SA)2), as established by reverse transcriptase-polymerase chain reaction, protein blot, and measurement of nitrite in the medium. Finally, beta-cell survival after IL-1beta + IFN-gamma treatment was significantly improved by IkappaB((SA)2) expression, mostly through inhibition of the apoptotic pathway. Based on these findings, we conclude that NF-kappaB activation, under in vitro conditions, has primarily a pro-apoptotic function in beta-cells.
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PMID:Inhibition of cytokine-induced NF-kappaB activation by adenovirus-mediated expression of a NF-kappaB super-repressor prevents beta-cell apoptosis. 1157 1

Cytokines have been implicated in pancreatic beta-cell destruction leading to type 1 diabetes. In vitro, a combination of gamma-interferon (IFN-gamma) and interleukin-1 (IL-1) stimulate inducible nitric oxide synthase (iNOS) expression in islets, and the resulting increased production of nitric oxide (NO) causes islet cell destruction. Islets contain macrophages, ductal cells, and endothelial cells that, when activated, may mediate islet cell damage by producing either NO themselves or cytokines that then stimulate NO production by beta-cells. The aim of this study was to determine whether beta-cell damage mediated by cytokine-induced NO production is dependent on beta-cell production of NO, or whether NO produced by other cells in the islet is capable of destroying beta-cells. To address this aim, we used transgenic mice expressing a dominant-negative IFN-gamma receptor in beta-cells (RIP-Delta(gamma)R). RIP-Delta(gamma)R islets are resistant to IL-1 + IFN-gamma-induced inhibition of insulin secretion and DNA damage, indicating that beta-cell IFN-gamma responsiveness is required for IL-1 + IFN-gamma-mediated beta-cell damage. Although islets isolated from RIP-Delta(gamma)R mice are resistant to functional damage, these islets produce NO in response to IL-1 + IFN-gamma, but at a lower concentration than that produced by wild-type islets. beta-Cells appear to be the primary cellular source of IL-1 + IFN-gamma-induced iNOS expression in wild-type islets. In contrast, IL-1 + IFN-gamma fail to stimulate iNOS expression by insulin-expressing cells in islets isolated from RIP-DeltagammaR mice. IL-1 + IFN-gamma-induced expression of iNOS was detected in non-beta-cells in both wild-type and RIP-DeltagammaR islets. These findings support the hypothesis that NO must be produced by beta-cells to induce damage.
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PMID:Interleukin-1 plus gamma-interferon-induced pancreatic beta-cell dysfunction is mediated by beta-cell nitric oxide production. 1181 37

Viral infections may trigger the autoimmune assault leading to type 1 diabetes mellitus. Double-stranded RNA (dsRNA) is produced by many viruses during their replicative cycle. The dsRNA, tested as synthetic poly(IC) (PIC), in synergism with the proinflammatory cytokines interferon-gamma (IFN-gamma) and/or IL-1 beta, results in nitric oxide production, Fas expression, beta-cell dysfunction, and death. Activation of the transcription nuclear factor-kappa B (NF-kappa B) is required for PIC-induced inducible nitric oxide synthase expression in beta-cells, and we hypothesized that this transcription factor may also participate in PIC-induced Fas expression and beta-cell apoptosis. This hypothesis, and the possibility that PIC induces expression of additional chemokines and cytokines (previously reported as NF-kappa B dependent) in pancreatic beta-cells, was investigated in the present study. We observed that the PIC-responsive region in the Fas promoter is located between nucleotides -223 and -54. Site-directed mutations at the NF-kappa B and CCAAT/enhancer binding protein-binding sites prevented PIC-induced Fas promoter activity. Increased Fas promoter activity was paralleled by enhanced susceptibility of PIC + cytokine-treated beta-cells to apoptosis induced by Fas ligand. beta-Cell infection with the NF-kappa B inhibitor AdI kappa B((SA)2) prevented both necrosis and apoptosis induced by PIC + IL-1 beta or PIC + IFN-gamma. Messenger RNAs for several chemokines and one cytokine were induced by PIC, alone or in combination with IFN-gamma, in pancreatic beta-cells. These included IP-10, interferon-gamma-inducible protein-10, IL-15, macrophage chemoattractant protein-1, fractalkine, and macrophage inflammatory protein-3 alpha. There was not, however, induction of IL-1 beta expression. We propose that dsRNA, generated during a viral infection, may contribute for beta-cell demise by both inducing expression of chemokines and IL-15, putative contributors for the build-up of insulitis, and by synergizing with locally produced cytokines to induce beta-cell apoptosis. Activation of the transcription factor NF-kappa B plays a central role in at least part of the deleterious effects of dsRNA in pancreatic beta-cells.
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PMID:Double-stranded RNA cooperates with interferon-gamma and IL-1 beta to induce both chemokine expression and nuclear factor-kappa B-dependent apoptosis in pancreatic beta-cells: potential mechanisms for viral-induced insulitis and beta-cell death in type 1 diabetes mellitus. 1189 77

Interleukin 1 (IL-1) is a pleiotropic cytokine with the potential to destroy pancreatic beta-cells, and thought to be involved in the pathogenesis of type I diabetes mellitus. Expression of inducible nitric oxide synthase (iNOS) and subsequent NO formation induced by IL-1beta may impair an islet function in rodents. Inhibition of iNOS may protect against cytokine-induced beta-cell suppression, although cytokines might also induce NO-independent impairment. To examine the role of NO in the IL-1beta treated cells, rat islets were treated with various concentrations (0, 0.5, 5, 50, 500 pmol/L) of IL-1beta with or without NG-monomethyl-L-arginine (NMMA; a competitive inhibitor of nitiric oxide synthase) for 2 or 6 h. Insulin secretion was stimulated in islets treated with 5, 50, and 500 pmol/ L of IL-1beta for 2 h and 0.5 pmol/L for 6 h, respectively. The stimulatory effect of IL-1beta on the insulin secretion of rat islets was not prevented by NMMA. Nitrate concentration was increased in a time- and concentration-dependent manner. Nitrate production was inhibited by NMMA. iNOS mRNA expression was increased at concentrations more than 5 pmol/L of IL-1beta in a dose dependent manner. iNOS mRNA was detectable after 2 h and peaked at 6 h but decreased after 24 h. These results suggested that the stimulatory effect of IL-1beta on the insulin secretion of rat islets is independent of iNOS-related NO production of IL-1beta and the enzyme activity of nitric oxide synthase.
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PMID:The stimulatory effect of IL-1beta on the insulin secretion of rat pancreatic islet is not related with iNOS pathway. 1198 73

The expression of IL-1beta in the NOD mouse pancreas was examined following disease acceleration with cyclophosphamide (Cy). Female NOD mice were injected with Cy at day 95 and the pancreas examined immunohistochemically at days 0, 4, 7, 11, and 14 (Cy group). Cyclophosphamide was also administered to NOD mice that were given oral nicotinamide from day 21. At day 0 (Cy group), IL-1beta was expressed in selective intraislet macrophages but showed an increase from day 7 onwards in macrophages, a few beta cells, and somatostatin cells. Peak expression was seen at day 11, when it was significantly higher than in day-11 mice given nicotinamide. In the Cy group a proportion of macrophages coexpressed IL-1beta and inducible nitric oxide synthase (iNOS). IL-1beta expressed within the islet macrophages may act in concert with other cytokines, promote free radical generation including NO, and promote beta cell death during IDDM.
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PMID:IL-1beta expression in islet cells of the NOD mouse and its spatial relationship to beta cells and inducible nitric oxide synthase. 1202 Nov 4

Cytokines released from activated antigen-presenting cells and T-lymphocytes are crucially involved in the pathogenesis of type 1 diabetes. Previous studies have shown that proinflammatory cytokines play an important role in the induction of autoimmunity and beta-cell damage. Inhibition of insulin expression has been described, but their effects on other major target autoantigens, such as the tyrosine phosphatase-like protein IA-2, is not known. In the present study, we established sensitive real-time RT-PCR to measure IA-2, insulin, and inducible nitric oxide (NO) synthase (iNOS) mRNA expression. Rat insulinoma INS-1 cells were stimulated with IL-1beta, TNF-alpha, interferon (IFN)-gamma, and IL-2 as well as with two combinations of these cytokines (C1: IL-1beta + TNF-alpha + IFN-gamma; C2: TNF-alpha + IFN-gamma). Treatment with IL-1beta, TNF-alpha, or IFN-gamma alone caused a significant down-regulation of IA-2 and insulin mRNA levels in a time and dose-dependent manner, whereas IL-2 had no effect. Exposure to cytokine combinations strongly potentiates the inhibitory effects. Incubation of cells with C1 and C2 for 24 h induces a significant inhibition of IA-2 mRNA levels by 78% and 58%, respectively. Under these conditions, an up to 5 x 10(4)-fold increase of iNOS gene expression was observed. The hypothesis that the formation of NO is involved in IA-2 regulation was confirmed by the finding that the coincubation of C1 with 4 mM L-N(G)-monomethyL-L-arginine, an inhibitor of the iNOS, partly reversed the down-regulation of IA-2. Further, incubation with the synthetic NO-donor S-nitroso-N-acetyl-D-L-penicillamine significantly decreased IA-2 mRNA level to 51% of basal levels. In conclusion, we have demonstrated for the first time that IL-1beta, TNF-alpha, and IFN-gamma exert a strong inhibitory effect on expression of the diabetes autoantigen IA-2. The action of IL-1beta may be partly mediated by the activation of the NO pathway.
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PMID:Effect of proinflammatory cytokines on gene expression of the diabetes-associated autoantigen IA-2 in INS-1 cells. 1223 95

We have developed a method to genotype variable number of tandem repeats (VNTRs) and insertion/deletion polymorphisms using an integrated microfluidic chip-based system. We used this method to analyze a) a highly polymorphic pentanucleotide repeat (CCTTT)(n) locus within the 5'-putative promoter region of the human inducible nitric oxide synthase gene (iNOS5) which is associated with diabetic complications and infectious diseases; b) a bi-allelic 27 bp VNTR region within intron 4 of endothelial nitric oxide gene (eNOS27) which is associated with hypertension in type 2 diabetes patients with coronary heart disease and excess risk of advanced diabetic nephropathy in type 1 diabetes patients and c) an insertion/deletion polymorphism within the gene encoding angiotensin-converting enzyme (ACE/ID) which is associated with cardiovascular pathology and nitric oxide activity, and is in strong linkage disequilibrium with functional variants. Following amplifications, samples were mixed with gel-dye and markers and loaded into commercially available microfluidic chips designed for DNA sizing applications. In the study (N = 230), 95 (41%) of the DNA samples were homozygous and 135 (59%) were heterozygous for the iNOS5 repeats. For eNOS27, 173 (75%) of the genotyped DNA samples were homozygous for the larger 4b allele and the remaining 57 samples (25%) were heterozygous (4b/4a). No DNA samples were homozygous for the shorter 4a allele with four 27 bp repeats. In case of ACE/ID, 47 (20%) of the DNA samples were homozygous for the insertion, 65 (28%) were homozygous for the deletion and the remaining 118 (51%) were heterozygous. The results obtained were verified by analyzing random amplicons using bi-directional sequencing and GeneScan 3.0 analyses with 100% concordance being observed. Using the microfluidic chip-based method, separation and DNA sizing and genotyping are rapidly accomplished. The DNA fragments are resolved clearly and the system allows quantitation. Finally, the microfluidic chip-based method may be used for both large- and small-scale genotyping studies.
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PMID:Microfluidic chip-based method for genotyping microsatellites, VNTRs and insertion/deletion polymorphisms. 1255 58

Tumor necrosis factor (TNF) is important in the pathogenesis of autoimmune diabetes. It has an important role in immunological and inflammatory processes, and has also been shown to induce apoptotic cell death. We have shown that TNF + IFNgamma induce islet cell death in vitro. TNF exists as a biologically active transmembrane molecule (tmTNF), which is then cleaved to form soluble TNF (sTNF). We reasoned that sTNF, which has been used in previous studies, may not represent TNF in its physiological form. We compared the contributions of caspase activation and nitric oxide production to beta cell death induced by either tmTNF or sTNF together with IFNgamma. CHO cells transfected with a mutated TNF were used as a source of tmTNF. Either sTNF or tmTNF, together with IFNgamma, induced caspase-dependent cell death of the NIT-1 insulinoma cell line, as measured by DNA fragmentation and a fluorogenic caspase 3 activation assay. TNF + IFNgamma did not induce caspase 3 activation in primary mouse islets. Instead, iNOS gene expression was induced and cell death which was partly NO-dependent occurred. We conclude that the role of TNF in the development of type 1 diabetes is likely to be the activation of gene expression and not apoptosis. It appears that both tmTNF and sTNF act by a similar mechanism to induce beta cell death.
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PMID:Transmembrane TNF and IFNgamma induce caspase-independent death of primary mouse pancreatic beta cells. 1256 16

We have been investigating the potential utility of engineered cell lines as surrogates for primary islet cells in treatment of type 1 diabetes. To this end, two strategies that have emerged for procuring cell lines with resistance to immune-mediated damage are 1) selection of cytokine-resistant cell lines by growth of INS-1 insulinoma cells in iteratively increasing concentrations of interleukin (IL)-1beta + gamma-interferon (IFN-gamma), and 2) stable overexpression of the anti-apoptotic gene bcl-2 in INS-1 cells. Herein, we show that bcl-2-overexpressing cells are resistant to the cytotoxic effects of reactive oxygen and nitrogen species (ROS/RNS), but are only modestly protected against high concentrations of IL-1beta + INF-gamma, whereas the converse is true in cytokine selected cells. We also found that the combination of bcl-2 expression and cytokine selection confers a broader spectrum of resistance than either procedure alone, such that the resultant cells are highly resistant to cytokines and ROS/RNS, with no impairment in glucose-stimulated insulin secretion. INS-1-derived cells with combined bcl-2 expression and cytokine selection are also more resistant to damage induced by coculture with mitogen-activated peripheral blood mononuclear cells. Surprisingly, application of the cytokine selection procedure to bcl-2-overexpressing cells does not result in impairment of nuclear factor-kappaB translocation, iNOS expression, and NO production, as clearly occurs upon application of the selection procedure to cells without bcl-2 overexpression. Further investigation of the diverse pathways involved in the development of cytokine and ROS/RNS resistance may define simplified and specific strategies for preservation of beta-cell mass.
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PMID:Discrete and complementary mechanisms of protection of beta-cells against cytokine-induced and oxidative damage achieved by bcl-2 overexpression and a cytokine selection strategy. 1276 53

Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) is a well-characterized murine model of the chronic-progressive form of human multiple sclerosis (MS) characterized by the activation of myelin-specific autoreactive CD4 Th1 cells via epitope spreading. To gain an understanding of the potential role of central nervous system (CNS)-resident cells in the presentation of endogenous myelin epitopes, we determined the individual antigen presentation and effector potential of resident microglia vs. infiltrating macrophages in the CNS of mice with ongoing TMEV-IDD by performing functional analysis of these populations separated to high purity by flow cytometric sorting based on their level of CD45 expression. Unlike microglia from nai;ve mice, peptide-pulsed CD45(lo) microglia isolated at the onset of clinical disease were as efficient as CNS-infiltrating CD45(hi) macrophages in activating proliferation and IFN-gamma production by myelin-peptide specific Th1 cells. In contrast, during the chronic stages of TMEV-IDD, CNS-infiltrating macrophages were more highly activated than the resident microglia as reflected both by higher expression of cell surface molecules associated with APC function and enhanced functional ability of spinal cord-infiltrating macrophages to stimulate T cell proliferation in vitro. Interestingly, both microglia and infiltrating macrophages expressed similar profiles of effector molecules such as IL-1, IL-6, IL-12 p40, TNF-alpha, and iNOS. Collectively, this is the first report comparing the antigen-presenting phenotype and function of microglia and infiltrating macrophages in a virus-induced model of CNS demyelination demonstrating that the resident microglia are capable APCs and may play an important role in antigen presentation at the onset of clinical disease and contribute to effector myelin destruction.
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PMID:Microglia are activated to become competent antigen presenting and effector cells in the inflammatory environment of the Theiler's virus model of multiple sclerosis. 1459


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