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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been proposed that certain cytokines secreted by islet-infiltrating leukocytes may be involved in the pathogenesis of insulin-dependent diabetes mellitus by participation in beta-cell destruction. In the present study, the impact of various cytokines on replication and long-term insulin secretion by pancreatic beta-cells was investigated. To this end, fetal rat pancreatic islets containing a high fraction of beta-cells were exposed in culture for 1-3 days to interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interferon-alpha (IFN-alpha), and interleukin-6 (IL-6) at different concentrations. It was found that IL-1 beta markedly decreased beta-cell DNA synthesis during the first day of exposure, an effect that vanished after 2 days and was turned into a potent and dose-dependent stimulation by 3 days of exposure. At this latter time point, IL-1 beta also amplified the mitogenicity of growth hormone (GH) and 16.7 mM glucose. In contrast, basal as well as glucose- and GH-stimulated insulin secretion was consistently suppressed by IL-1 beta from days 1-3. IL-1 beta also lowered the islet adenosine 3',5'-cyclic monophosphate (cAMP) content at all time points studied. However, addition of the stimulatory cAMP analogue Sp-diastereomer of adenosine 3',5'-cyclic monophosphothioate or pertussis toxin, which themselves enhanced DNA synthesis and insulin secretion, failed to prevent the inhibitory actions of IL-1 beta on these parameters, making it unlikely that a decrease in cAMP is an important event in transduction of the inhibitory effects of the cytokine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Differential effects of cytokines on long-term mitogenic and secretory responses of fetal rat pancreatic beta-cells. 132 36

Insulin-dependent diabetes mellitus is an autoimmune phenomenon in humans. At onset, the diabetic pancreas shows a well-characterized insulitis. The inflammatory cells are specifically directed toward beta cells of the pancreatic islets. Several hypotheses link genetic susceptibility for diabetes to immunologic mechanisms. The cytokines interferon gamma and interleukin-6 have essential roles in the progressive destruction of beta cells. Studies with experimental models may improve definition of the pathogenesis of insulin-dependent diabetes mellitus. Combining genetic studies that detect susceptibility to insulin-dependent diabetes mellitus with future therapies aimed at interrupting cytokine production or cytokine receptor expression may lead to prevention of insulin-dependent diabetes mellitus.
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PMID:Cytokines and the pathogenesis of insulin-dependent diabetes mellitus. 142 73

The aim of this study was to establish a cytokine-free, serum-free system which would enable the long-term survival and proliferation of human peripheral blood monocytes. Monocytes were isolated from peripheral blood mononuclear cells (PBMC) by adherence to untreated plastic petri dishes and maintained up to 6 weeks in serum-free medium (SFM) consisting of IMEM, insulin, transferrin, sodium selenite and BSA. Maximal cell proliferation occurred during the first 2 weeks of culture and corresponded to the appearance of large numbers of pure, nonadherent culture-derived macrophages. Monocyte maturation was characterised by the modulation of specific cell surface antigens. The percentage of cells staining for the transferrin receptor increased with time, whereas the percentages of cells expressing CD11b, CD11c and HLA-DR remained greater than 60% for the 15 days studied. The mean fluorescent intensities (MFI) of all these antibodies increased significantly with time. The only differences found between the adherent and nonadherent cells, using the above antibodies, were with the MFI for CD11b and CD11c. In both cases, the intensity of staining was significantly greater in the adherent cells. Estimation of cytokine production by cells maintained for 5 weeks in SFM found that they constitutively produced large amounts of macrophage colony-stimulating factor (M-CSF) in the absence of any exogenous stimuli. These cells were also found to secrete high levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) during the 1st week and granulocyte macrophage colony-stimulating factor (GM-CSF) during the 3rd week. However, the addition of exogenous GM-CSF (5 U/ml, S5) was found to significantly inhibit monocyte proliferation up to 17 days. This is the first report of proliferation associated with long-term survival of culture derived macrophages in a serum-free, cytokine-free system.
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PMID:Monocyte proliferation in a cytokine-free, serum-free system. 151 90

Viral infection has been suggested to play a triggering role in the pancreatic beta cell destruction which occurs in insulin-dependent diabetes (IDDM). However, the underlying mechanism of this phenomenon is unknown. In this study a human insulinoma cell line has been infected with measles, mumps and rubella viruses since a temporal association is reported between the clinical onset of IDDM and diseases caused by these viruses. The infection with measles and mumps viruses induced the release of interleukin-1 (IL-1) and interleukin-6 (IL-6) by the cell line as assessed by a bioassay and up-regulated the expression of human leucocyte antigen (HLA) class I and class II antigens as evaluated by cytofluorimetric analysis. Stimulation with rubella virus induced the release of IL-6 only and had no effect on HLA antigen expression. These data show for the first time that IL-1 and IL-6 secretion by an insulinoma cell line may occur after viral infection and suggest that cytokine release and increased expression of HLA molecules by beta cells may act to induce the immune response towards beta cells in IDDM.
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PMID:Viral infection induces cytokine release by beta islet cells. 159 39

The controversial role of interleukin-6 (IL-6) as an auto- or paracrine growth factor for human multiple myeloma (MM) cells was studied using a panel of six well characterized feeder-cell dependent and independent MM cell lines as models. With respect to the effect of IL-6 on growth and survival, three types of lines were found: (1) U-1958, dependent on IL-6 both for growth and survival; (2) U-1996, dependent on IL-6 for growth but not survival; and (3) U-266-1984, Fravel, L363, and Karpas 707, independent of IL-6. Feeder-cell supernatants were as efficient as feeder-cell monolayers in stimulating growth and contained IL-6 as the only growth promoting activity. IL-6 was growth stimulatory and sustained the growth of U-1958 only when the medium contained fetal calf serum. The nature of the serum factor(s) is unknown, but it was excluded to be the IL-6 carrier protein a2-macroglobulin. IL-1, IL-2, IL-3, TNF-alpha, GM-CSF, IGF-1, and insulin were neither co-stimulatory with IL-6 nor stimulated growth on their own. Only U-266-1984 expressed IL-6 mRNA. IL-6 receptor mRNA was expressed in all lines except the L363 and Fravel. We conclude that the response to IL-6 is heterogeneous among the MM lines and that IL-6 acts as a paracrine growth factor for two of six lines. In a third line, U-266-1984, the IL-6 mRNA expression suggests the possibility of an autocrine growth stimulation.
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PMID:Heterogeneity in response to interleukin 6 (IL-6), expression of IL-6 and IL-6 receptor mRNA in a panel of established human multiple myeloma cell lines. 170 69

Stimulation of the immune system results in a series of metabolic changes that are antagonistic toward growth. Monokines, including interleukin-1, tumor necrosis factor, and interleukin-6, are released from cells of the monocyte-macrophage lineage after recognition of immunogens. They appear to mediate homeorhetic response, which alters the partitioning of dietary nutrients away from growth and skeletal muscle accretion in favor of metabolic processes which support the immune response and disease resistance. These alterations include 1) decreased skeletal muscle accretion due to increased rates of protein degradation and decreased protein synthesis; 2) increased basal metabolic rate resulting in increased energy utilization; 3) use of dietary amino acids for gluconeogenesis and as an energy source instead of for muscle protein accretion; 4) synthesis by the liver of acute phase proteins; 5) redistribution of iron, zinc, and copper within the body due to the hepatic synthesis of metallothionein, ferritin, and ceruloplasmin; (6) impaired accretion of cartilage and bone; and 7) release of hormones such as insulin, glucagon, and corticosterone. These monokines also influence the differentiation of cells. Tumor necrosis factor suppresses the differentiation of myoblasts and adipocytes whereas the chicken monokine myelomonocytic growth factor induces the differentiation of granulocytes.
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PMID:Monokines in growth and development. 171 68

Transforming growth factor-beta (TGF beta 1), a multipotent immunoregulatory peptide produced by human platelets, has been shown to stimulate the synthesis of fibrinogen, contrapsin, complement component C3, and alpha-1-proteinase inhibitor by murine hepatocytes cultured for 2 days in DMEM containing 1 microM insulin and dexamethasone and 0.2% BSA. In the range of 10 pg to 10 ng/ml TGF-beta 1 did not elicit any change in albumin secretion. Two main inflammatory cytokines: interleukin-6 (IL-6) and interleukin-1 (IL-1), known to stimulate two different subsets of murine acute phase plasma proteins, failed to increase contrapsin and alpha-1-proteinase inhibitor production. Epidermal growth factor (EGF) in the concentration 1 ng to 10 ng/ml effectively counteracted the stimulatory effect of TGF-beta 1 on acute phase protein production. TGF-beta 1-induced fibrinogen protein levels were associated with increased beta-fibrinogen mRNA content. TGF-beta 1 appears to be an additional physiological factor responsible for the direct stimulation of normal mouse hepatocytes to acute phase response.
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PMID:Regulation of acute phase reaction by transforming growth factor beta in cultured murine hepatocytes. 172 35

Liver fat-storing cells (FSC) play an important role in collagen deposition. During the induction of liver cirrhosis, FSC lose their fat droplets, acquire an actin-rich cytoskeleton and transform into myofibroblasts. Myofibroblasts have been associated with increased collagen production in cirrhotic livers. Cultured FSC resemble myofibroblasts. However, it is not known whether regulation of collagen gene expression is similar in FSC obtained from normal or cirrhotic livers. In this communication, we describe the characterization of two fat-storing cell lines, one from normal (NFSC) and one from CCl4-cirrhotic liver (CFSC), obtained after spontaneous immortalization in culture. We studied the effect of serum and various growth factors on cell proliferation. We determined the production of collagen and fibronectin and we analyzed the presence of mRNA transcripts of collagens type I, III, and IV, fibronectin laminin, transforming growth factor-beta and interleukin-6. We found that CFSC have a greater serum-dependency than NFSC. NFSC grow with a mixture of insulin and epidermal growth factor, whereas CFSC proliferate only with platelet-derived growth factor. Although we did not find significant differences in the expression of mRNAs for collagen type I, fibronectin and transforming growth factor-beta, collagen and fibronectin synthesis was increased 2- and 1.5-fold respectively. NFSC contained 1.6- and 2.0-fold more type III collagen and laminin mRNAs, respectively, than CFSC. Neither cell line expressed type IV collagen mRNA. NFSC but not CFSC produced interleukin-6. These results suggest that, except for the lack of transcripts of collagen type IV, both cell lines resemble primary cultures of FSC. However, significant differences in cell proliferation and interleukin-6 production between the two cell lines were found. We suggest that these cell lines could be useful tools to study possible differences in regulation of matrix production by FSC.
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PMID:Characterization of fat-storing cell lines derived from normal and CCl4-cirrhotic livers. Differences in the production of interleukin-6. 175 10

It has been proposed that certain cytokines secreted by islet-infiltrating leukocytes may be involved in the pathogenesis of insulin-dependent diabetes mellitus. Since the cytotoxic actions by the cytokines may reflect interactions with islet cell types other than the beta-cell, in this work I have investigated the effects of different combinations of various cytokines on the proliferation and hormone content and secretion by a pure insulin-producing cell population, i.e., the clonal rat insulinoma cell line RINm5F. For this purpose RINm5F cells were exposed in culture for 1-2 days to interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma) and interferon alpha (IFN-alpha) at different concentrations. It was found that IL-1 beta markedly decreased the cellular content of insulin and secretion of the hormone into the culture medium, while causing a very slight inhibition of RINm5F cell proliferation. On the other hand, IFN-gamma and IFN-alpha both elicited marked decreases in proliferation and insulin content and secretion by the insulinoma cells. IL-6 and TNF-alpha were found not to affect these parameters. No additive or synergistic effects were observed when the cytokines were added in various combinations. There was no protection against the cytotoxicity of IL-1 beta, IFN-gamma or IFN-alpha by pre-treatment with pertussis toxin. From these findings it is concluded that the cytokines IL-1 beta, IFN-gamma and IFN-alpha act in a non-synergistic fashion in suppressing RINm5F cell proliferation and hormone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cytokines inhibit proliferation and insulin secretion by clonal rat insulinoma cells (RINm5F) non-synergistically and in a pertussis toxin-insensitive manner. 195 44

Using a functioning rat thyroid cell line (FRTL-5), we examined the effects of some cytokines, particularly interleukin-1 (IL-1) on the growth of thyroid cells. In 5H medium, namely Coon's modified Ham's F-12 medium supplemented with 5% calf serum and a five-hormone preparation consisting of insulin, hydrocortisone, transferrin, glycyl-L-histidyl-L-lysine acetate and somatostatin, IL-1 enhanced the growth of FRTL-5 cells detected by [3H]TdR incorporation. However, in 6H medium (5H medium plus bovine TSH), IL-1 inhibited the growth of FRTL-5 cells. Both effects were neutralized by the addition of anti-IL-1 antibody. Furthermore, IL-1 inhibited the growth of FRTL-5 cells induced by forskolin which is known as an adenylate cyclase activator. FRTL-5 cells have specific IL-1 receptors detected by the binding of 125I-labeled IL-1 alpha. By Scatchard plot analysis, the numbers and the dissociation constants of IL-1 receptors on FRTL-5 cells were shown to be 5225/cell and 8.69 x 10(-10) M. Interleukin-2, interleukin-6 and interferon-gamma (IFN-gamma) had no significant effects on the cell growth in 6H medium, while IFN-gamma and insulin-like growth factor I stimulated cell growth somewhat in 5H medium. These results suggest that IL-1 plays a regulatory role in the growth of thyroid cells through binding to the IL-1 receptors.
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PMID:Inhibitory effect of IL-1 on the TSH dependent growth of rat thyroid cells (FRTL-5). 212 71


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