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

Viruses are implicated in the pathogenesis of beta-cell destruction in type I (insulin-dependent) diabetes. The aim of our study was to investigate whether reovirus 1 or reovirus 3, which are known to infect beta-cells and induce autoimmunity in susceptible mice, could alter the expression of the major histocompatibility complex (MHC) proteins by human beta-cells and rat insulinoma RINm5F cells. Forty-eight hours after infection of either human beta-cells or RINm5F cells with reovirus 1 or reovirus 3, cytopathic effects were noted. By flow-cytofluorometric analysis, infected RINm5F cells exhibited a seven- to eightfold increase in the surface expression of class I MHC proteins. Upregulation of class I MHC proteins on reovirus 3-infected RINm5F cells was inhibited by 80% after preexposure of the virus to reovirus 3 antiserum. When analyzed by double-indirect immunofluorescence microscopy, human beta-cells infected with reoviruses 1 or 3 also exhibited markedly increased levels of class I MHC proteins. Reovirus infection of human beta-cells or RINm5F cells was not accompanied by the induction of class II MHC proteins. These findings suggest that 1) in addition to direct cytopathic effects, reovirus infection may contribute to beta-cell destruction by increasing expression of class I MHC proteins and therefore reactivity with cytotoxic T-lymphocytes; and 2) some viruses may increase MHC protein expression independent of and before the action of cytokines (e.g., interferon-gamma and tumor necrosis factor) released by immunoinflammatory cells.
Diabetes 1988 Mar
PMID:Reovirus infection enhances expression of class I MHC proteins on human beta-cell and rat RINm5F cell. 283 51

The ability of recombinant interferon-gamma (rIFN-gamma) to induce major histocompatibility complex (MHC) antigen expression in the rat insulinoma cell line RINm5F was investigated. The cells were stained with monoclonal antibodies specific for rat class I and class II MHC antigens. RINm5F cells endogenously expressed class I antigens; this was enhanced by rIFN-gamma. Class II antigens could not be detected on RINm5F cells, but both I-A and I-E were induced by rIFN-gamma.
Diabetes 1988 Feb
PMID:Interferon-gamma induces class II MHC antigens on RINm5F cells. 283 86

To examine whether products of the immune system interact with the pancreatic beta-cell, rat insulinoma cells (RIN-m5F line) were cultured in the presence of conditioned medium from concanavalin A-activated mouse spleen cells (CAS medium). Indirect immunofluorescence and flow cytometry revealed that after culture in CAS medium, RIN-m5F cells had an 8- to 10-fold increase in class I major histocompatibility complex (MHC) proteins, whereas class II MHC proteins remained undetectable, and the level of insulin and/or insulin-like growth factor 1 receptors was unchanged. The stimulation of class I MHC expression on RIN-m5F cells by CAS medium could be mimicked by recombinant interferon-gamma. Analysis of 125I-surface-labeled cells by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography revealed that in the presence of CAS medium, there was a major increase in the expression of proteins of 48,000, 32,000, and 12,000 Mr and a minor increase in proteins of 17,000 and 9,000 Mr. Precipitation with monoclonal antibody identified the 48,000- and 12,000-Mr proteins as the class I MHC protein and beta 2-microglobulin, respectively. The ability of lymphokine-conditioned medium to increase the expression of RIN-m5F cell surface proteins, including the class I MHC proteins, provides a potential mechanism for enhancing the immune-mediated destruction of the beta-cell.
Diabetes 1986 Nov
PMID:Expression of class I MHC proteins on RIN-m5F cells is increased by interferon-gamma and lymphokine-conditioned medium. 301 6

We have recently shown that interferon-gamma (IFN-gamma) markedly upregulates the expression of the class I major histocompatibility proteins on pancreatic beta cells and have therefore postulated that interferon-gamma may enhance cytotoxic lymphocyte-mediated beta cell damage in insulin-dependent diabetes mellitus. To further explore the interaction between interferon-gamma and the pancreatic beta cell we have used the RIN-m5F insulinoma line to define the effects of interferon-gamma on major histocompatibility protein expression, (pro)insulin and protein synthesis and cell growth. Interferon-gamma induced a dose-dependent increase in the expression of the class I major histocompatibility proteins on the RIN-m5F cells, the maximal increase (10-fold) being seen at an interferon-gamma concentration of 1 U/ml. The induction of class I proteins by interferon-gamma was nearly completely abolished by cycloheximide. Expression of class II (Ia) proteins was not detected either in the presence or absence of interferon-gamma. (Pro)insulin and protein synthesis were decreased by 60% and 40%, respectively, in RIN-m5F cells cultured with interferon-gamma (10 U/ml). Furthermore, the growth of RIN-m5F cells was significantly inhibited, and corresponding changes in cell morphology were evident, after 3 days of exposure to interferon-gamma (10 U/ml). These findings indicate that, in addition to its potential role in amplifying cytotoxic T cell activity against the pancreatic beta cell, IFN-gamma may also directly inhibit beta cell function and growth. Several mechanisms could therefore account for an ability of IFN-gamma to compromise beta cell function and contribute to the pathogenesis of insulin-dependent diabetes.
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PMID:Interferon-gamma: pleiotropic effects on a rat pancreatic beta cell line. 304 Apr 96

Modulation in major histocompatibility complex (MHC) gene expression correlates with the inflammatory reactions that occur during graft rejection and autoimmune disease. We analyzed the expression of class I and II MHC genes in the pancreatic islets of prediabetic and newly diabetic BB rats by immunohistochemistry of tissue sections and Northern blotting of RNA extracted from isolated islets. We show that enhanced levels of MHC class I heavy-chain RNA are present in pancreatic islets before overt inflammation and the onset of insulin-dependent diabetes mellitus (IDDM) in the spontaneously diabetic BB rat. Immunohistochemical analysis revealed enhanced class I antigen expression throughout the pancreatic islets of newly diabetic animals but no induction of class II antigen on endocrine cells within the islet. Varying degrees of inflammatory infiltrate were observed in the sections exhibiting enhanced class I antigen expression or in nearby serial sections. Southern blot analysis revealed no restriction-fragment-length polymorphism or amplification of the endogenous class I heavy-chain genes compared with those of seroidentical disease-resistant Wistar-Furth rats. I-A alpha and I-E alpha hybridizing RNA appeared de novo before overt diabetes, although concomitantly with T-lymphocyte-receptor beta-chain and interferon-gamma gene hybridizing RNA and after MHC class I heavy-chain RNA enhancement was observed. These data indicate the possibility that enhanced class I heavy-chain gene expression plays a role in the progression of IDDM.
Diabetes 1988 Oct
PMID:IDDM in BB rats. Enhanced MHC class I heavy-chain gene expression in pancreatic islets. 304 71

Islets from male B10.BR mice (H-2k) were isolated by the collagenase technique, handpicked with a Pasteur pipette, and incubated (either intact or after dispersion with Dispase) for 0, 3, 5, 7, 10, or 14 days in tissue culture medium supplemented with either lymphokine supernatants or recombinant murine interferon-gamma. Islets and single cells were examined for IAk molecules by use of indirect immunofluorescence. Ia-positive islet cells were identified on the surface of islets incubated with 5-10% lymphokine for greater than 4 days or with 10, 100, or 1000 ng/ml interferon for greater than 6 days. Islets incubated in unsupplemented medium were Ia negative. Incubation with 5% lymphokine induced Ia expression on 10-40% dispersed islet cells cultured for greater than 9 days. Dual immunofluorescent staining for Ia and insulin revealed that Ia-positive cells included both beta- and non-beta-cells.
Diabetes 1986 Oct
PMID:Interferon-mediated induction of Ia antigen expression on isolated murine whole islets and dispersed islet cells. 309

HLA class II molecules are surface glycoproteins which are essential in the initiation of immune responses. It has been postulated that induction of class II in epithelial cells such as endocrine cells, which are normally class II negative, may result in autoimmunity. In type I diabetes, islet beta cells, the target of the autoimmune process, selectively express class II antigens. But in contrast to most other cell types, islet beta cells are not stimulated to express class II by interferon-gamma (IFN-gamma) and thus the conditions under which this induction occurs have been particularly elusive. The cytotoxins tumour necrosis factor (TNF) and lymphotoxin (LT) synergize with IFN-gamma in a number of activities. We report here that IFN-gamma in combination with either TNF or LT induces islet cell class II expression. This finding has important implications for the pathogenesis of type I diabetes and the understanding of the differential control of class II expression.
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PMID:HLA class II induction in human islet cells by interferon-gamma plus tumour necrosis factor or lymphotoxin. 310 76

An assay was developed to detect the cytotoxic effects of cytokines on rat pancreatic islet cells in monolayer culture. Cell lysis was detected by a 51Cr-release assay after 4 days of incubation with various cytokines. When tested alone, murine (rat and mouse) interferon-gamma (mIFN-gamma) produced a small dose-dependent lysis of islet cells; human IFN-gamma, mouse IFN-alpha/beta, interleukins 1 and 2 (IL-1 and IL-2), tumor necrosis factor (TNF), and lymphotoxin (LT) were inactive. When added together, the following combinations of cytokines showed synergistic cytotoxic effects: TNF (or LT) plus IL-1, TNF (or LT) plus mIFN-gamma, and IL-1 plus mIFN-gamma. These results indicate that the cytokine products of mononuclear cells of the immune system, IFN-gamma, TNF, LT, and IL-1 have strong synergistic cytotoxic effects on islet cells and therefore may act as direct chemical mediators of islet beta-cell destruction in type I (insulin-dependent) diabetes.
Diabetes 1988 Jan
PMID:Destruction of rat islet cell monolayers by cytokines. Synergistic interactions of interferon-gamma, tumor necrosis factor, lymphotoxin, and interleukin 1. 312 15

Endocrine epithelial cells do not normally express human leukocyte antigen (HLA) class II molecules, but do so in a variety of autoimmune diseases. This finding suggests the hypothesis that such inappropriate class II-positive expression may enable these cells to present autoantigens and thus contribute to autoimmune pathogenesis. Indeed, class II-positive thyrocytes can present both exogenous antigenic peptides and intrinsic autoantigens to the appropriate T cells. Class II expression by thyrocytes can be induced by interferon-gamma, and is positively and negatively regulated by thyroid-stimulating hormone and epidermal growth factor, respectively. Furthermore, heterogeneity of thyrocyte class II subregion expression appears to be related to the nature of the inducing stimulus. The complexity of regulatory signals is underlined by findings in type I diabetes: islet beta cells aberrantly express class II in this disease, but class II cannot be induced in normal beta cells by interferon-gamma.
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PMID:New ideas in thyroid autoimmunity. 329 60

We compared the cytotoxic effects to islet cells of lymphoid cells from diabetic and diabetes-resistant (DR) BioBreeding/Worcester (BB/W) rats with a 51Cr-release assay to detect lysis of normal rat islet cells. Splenic lymphoid cells from diabetic rats were more cytotoxic to islet cells (11.3 +/- 3.8%) than were lymphoid cells from DR rats (4.0 +/- 2.6%). This difference was amplified by incubating the lymphoid cells for 20 h with 5 micrograms/ml concanavalin A (ConA); islet cell lysis was 39.3 +/- 4.5% by ConA-activated diabetic cells and 9.6 +/- 2.7% by ConA-activated DR cells. The cytotoxic lymphoid cells were identified as natural killer (NK) cells, because treatment of diabetic lymphoid cells with anti-asialo GM1 serum and complement selectively removed a monoclonal antibody-defined subset of NK cells (OX8 +), and the NK-depleted lymphoid cells were not cytotoxic to either islet or NK-sensitive YAC-1 cells, even after culture with ConA. Of several lymphokine products of ConA-stimulated lymphoid cells, interleukin 2 (IL-2), but not interleukin 1 or interferon-gamma, significantly activated splenic lymphoid cells cytotoxic to islet cells, and the lymphoid cells from diabetic rats were more sensitive to IL-2 (3 U/ml) than were the cells from DR rats (30 U/ml). This study reveals the presence of ConA- and IL-2-responsive islet cytotoxic NK cells in the diabetic BB/W rat and suggests that IL-2 activation of NK cells may contribute to islet beta-cell destruction and diabetes in this animal.
Diabetes 1987 Nov
PMID:Interleukin 2 activates BB/W diabetic rat lymphoid cells cytotoxic to islet cells. 331 52


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