UNIPROT:P05231 - FACTA Search

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

Interleukin-6 (IL-6) is produced by adrenal zona glomerulosa cells; its release is stimulated by several secretagogues, including IL-1 alpha, IL-1 beta, and angiotensin II. The present study reports that ACTH (0.1-100 nM) increased the release of IL-6 from primary cultures of rat adrenal cells in a concentration-dependent manner. This increase was accompanied by an increase in cAMP content in cell extracts and in the incubation medium. The dynamics of IL-6 release from the adrenal cells also were investigated using a perifusion system; approximately 50 min were required for the effects of IL-1 alpha, IL-1 beta, and ACTH on IL-6 release to become apparent. Following withdrawal of the secretagogues, IL-6 release returned to basal levels within 90-120 min. In some experiments, the adrenal zona glomerulosa was separated from the zona fasciculata/reticularis to determine the origin of secretagogue-stimulated IL-6 release. PGE2 and forskolin increased IL-6 release from both cell types, but maximal release from zona glomerulosa cells was more than 10-fold greater than that from zona fasciculata/reticularis cells. ACTH (0.1-100 nM) increased intracellular cAMP levels in cells from both cell types in a concentration-dependent manner, but increased IL-6 release only from zona glomerulosa cells. Dexamethasone, an inhibitor of IL-6 production in several tissues, had no effect on either basal or stimulated IL-6 production in the adrenal. Because IL-1 beta is produced primarily by tissues of the immune system, whereas ACTH is a classical endocrine hormone, we investigated the effect of interaction of these proteins on IL-6 release from the adrenal. Together, IL-1 beta and ACTH stimulation of IL-6 release was greater than the sum of the effects of each substance separately; however, IL-1 beta did not potentiate the effect of ACTH on cAMP levels. Similarly, IL-1 beta potentiated IL-6 release stimulated by forskolin and (Bu)2cAMP. Thus, the adrenal may be an important convergence point between the immune and endocrine systems, and because IL-6 release is regulated by IL-1 alpha, IL-1 beta, ACTH, and angiotensin II, and this cytokine stimulates corticosterone release, IL-6 may play an important paracrine role in integrating the signals derived from these systems.
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PMID:Adrenocorticotropin increases interleukin-6 release from rat adrenal zona glomerulosa cells. 131 Dec 32

The expression of 80 kDa interleukin-6 receptor (IL-6R) and the associated molecule gp130 has been studied on human cell lines by FACS- and Northern blot analysis. The effects of dexamethasone, dibutyric-(DB)-cAMP and phorbol-12-myristate-13-acetate (TPA) have been studied on plasmacytoma cell line U266, B cell line BMNH and monocytoid cell line U937. Our data show a definite downregulation of IL-6R and gp130 expression by TPA in U266 and BMNH at both mRNA and cell surface protein levels. In U937 TPA inhibits only the IL-6R expression, without affecting that of gp130. DB-cAMP decreases the expression of both proteins in U937, slightly inhibits the IL-6R expression in U266, but is uneffective in BMNH. Dexamethasone induces considerable upregulation of gp130 only in U266. Our findings suggest separate regulation of IL-6R and gp130 on U266, BMNH and U937 cell lines.
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PMID:Regulation of IL-6 receptor and gp130 expression on human cell lines of lymphoid and myeloid origin. 133 86

Cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage-CSF (M-CSF), neutrophil-activating peptide-1/interleukin-8 (NAP-1/IL-8), and interleukin-6 (IL-6) are pivotal in the regulation of hematopoiesis and immune responses. In mesenchymal cells, their expression is induced by tumor necrosis factor alpha (TNF) and other agents. We now show that, while induction of cytokine expression by TNF in human lung fibroblasts was parallel, glucocorticoid hormones differentially affected their production. Dexamethasone (1 mumol/L) concordantly repressed expression of GM-CSF, NAP-1/IL-8 and IL-6. RNA and protein levels were reduced to approximately 5%, 20%, and 30% of control cells, respectively, as determined by Northern blot analyses and immunoassays. A 50% reduction of RNA levels for all three cytokines occurred in the range of 1 hour. In contrast, dexamethasone (1 mumol/L) did not decrease M-CSF RNA levels and protein release. M-CSF RNA and protein levels were maintained even when dexamethasone (1 mumol/L) was present for the whole duration of a 48-hour TNF stimulation. Further experiments showed that dexamethasone downregulates expression of GM-CSF, NAP-1/IL-8, and IL-6 mainly by decreasing the mRNA stability of these cytokines, and that the dexamethasone-mediated repression of cytokine expression depends on ongoing protein and RNA syntheses. Our study suggests that glucocorticoid hormones repress expression of a set of cytokine genes important in conditions of stress. However, they seem not to affect M-CSF expression, which is likely to be more crucial in maintaining long-term functions of myeloid cells.
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PMID:Glucocorticoids downregulate gene expression of GM-CSF, NAP-1/IL-8, and IL-6, but not of M-CSF in human fibroblasts. 137 Feb 8

Interleukin-6 (IL-6) relays an important signal to hepatocytes during the early stages of an acute inflammatory response, causing an alteration in the expression of several major defense proteins. Additional regulation of this signal could occur either by altering the number of IL-6 receptors (IL-6-R) or of the signal transducing protein, gp130. We employed ribonuclease protection assays to measure the expression of IL-6-R and gp130 mRNA in primary rat hepatocytes in response to IL-6, interleukin-1, dexamethasone, and combinations thereof. Dexamethasone increases receptor mRNA levels 2.7-fold above controls but has no detectable effect on that of gp130. Such treatment increased surface expression of IL-6-R from 600 receptors per cell to greater than 6000, without a change in Kd (2.5-4.6 x 10(-10) M). In contrast to the stimulatory effect of the steroid signal, the inflammatory cytokines, individually and together, down-modulated both the mRNA and the cell surface expression of IL-6-R. These findings demonstrate for the first time that a sensitive control system exists between inflammatory mediators and IL-6-R.
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PMID:Differential regulation of interleukin-6 receptor and gp130 gene expression in rat hepatocytes. 155 Sep 52

Previous studies have demonstrated that Na(+)-dependent brush border glutamine transport is diminished in septic patients. To examine the potential regulation of this decreased transport by endotoxin, cytokines, or glucocorticoids, the human intestinal Caco-2 cell line was studied in vitro. Na(+)-dependent glutamine transport across the apical brush border membrane was assayed in confluent monolayers of differentiated cells that were 10 days old. Uptake of 50 microM glutamine was determined after a 12-hour incubation with varying doses (10 to 1000 U/mL) of tumor necrosis factor-alpha, interleukin-1, interleukin-6, interferon-gamma, and various combinations of these cytokines. Studies were also done in cells incubated with E. coli endotoxin (1 micrograms/mL) or dexamethasone (1 and 10 microM). Endotoxin, tumor necrosis factor, interleukin-1, and interleukin-6 alone and in combination did not significantly reduce Na(+)-dependent glutamine transport across the brush border of Caco-2 cells. Dexamethasone decreased glutamine transport by 20%, but this decrease was not apparent for 48 hours. Interferon consistently decreased glutamine transport by 30%; this was due to a reduction in carrier maximal transport velocity (3427 +/- 783 pmol/mg protein/minute in controls versus 2279 +/- 411 in interferon, p less than 0.05) rather than a change in Km (276 +/- 29 microM in controls versus 333 +/- 74 in interferon, p = not interferon + dexamethasone + tumor necrosis factor + interleukin-1 resulted in a 38% decrease in transport activity. Cytokines and glucocorticoids may work independently and synergistically in regulating Na(+)-dependent brush border glutamine transport in human intestinal cells. Whether these signal molecules play a central role in the cause of the diminished brush border glutamine transport that occurs in septic patients requires further study.
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PMID:Cytokine modulation of Na(+)-dependent glutamine transport across the brush border membrane of monolayers of human intestinal Caco-2 cells. 161 90

During the acute phase response to bacterial endotoxin in rats, hepatic levels of cytochrome P450IIC12 [AH, reduced flavoprotein:oxygen oxidoreductase (RH hydroxylating), EC 1.14.14.1] (P450IIC12) apoenzyme and mRNA are suppressed. We set out to determine the effects of potential humoral mediators of inflammation on the expression of P450IIC12 in female rats. A single injection of 12,000 or 60,000 units of interleukin-1 alpha had no effect on total cytochrome P450 content or P450IIC12 mRNA measured 12 hr later, although P450IIC12 apoenzyme was slightly but significantly increased by the higher dose. In the second experiment, animals were given dexamethasone (100 micrograms/kg at -30 min), interleukin-1 alpha (30,000 units/kg at 0, 2, and 4 hr), or both and were sacrificed at 12 hr. Treatment with interleukin-1 alpha alone significantly suppressed total cytochrome P450, P450IIC12 apoenzyme, and P450IIC12 mRNA to 77, 53, and 65% of control levels, respectively; beta-actin mRNA was significantly increased (206% of control levels). Treatment with dexamethasone alone suppressed total cytochrome P450 and P450IIC12 mRNA (73% of controls) but did not significantly affect P450IIC12 apoenzyme measured 12.5 hr later. Again, beta-actin mRNA was increased. When both interleukin-1 alpha and dexamethasone were given, total cytochrome P450 and P450IIC12 mRNA (43% of controls) were suppressed, and beta-actin mRNA was significantly increased. In the third experiment, animals were injected at 0 and 12 hr with dexamethasone (83 micrograms/kg), interleukin-6 (33 micrograms/kg), or both. Interleukin-6 alone did not significantly affect total cytochrome P450 or P450IIC12 apoenzyme or mRNA. Dexamethasone alone suppressed P450IIC12 apoenzyme and mRNA (to 52 and 41%, respectively, of controls). Treatment with both interleukin-6 and dexamethasone significantly suppressed total cytochrome P450 and P450IIC12 apoenzyme and mRNA; suppression of P450IIC12 mRNA (to 16% of controls) was greater than with dexamethasone alone. No change in the transcription rate of CYP2C12 was observed 24 hr after initiation of treatment with dexamethasone (83 micrograms/kg at 0 and 12 hr) or 12 hr after initiation of treatment with interleukin-1 alpha (30,000 units/kg at 0, 2, and 4 hr). We conclude that, in this model, interleukin-1 alpha and glucocorticoids are important mediators of the suppression of hepatic P450IIC12 expression during inflammation. Interleukin-6 was not as potent, but it did potentiate the effects of dexamethasone. Suppression of P450IIC12 expression by dexamethasone and interleukin-1 alpha appeared to be mediated at a pretranslational level, but the possibility of a transcriptional effect needs to be further investigated.
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PMID:Regulation of cytochrome P450IIC12 expression by interleukin-1 alpha, interleukin-6, and dexamethasone. 201 47

Gram-negative bacterial infections of the urinary tract elicit a mucosal inflammatory response. Interleukin-6 is secreted into the urine, and polymorphonuclear leukocytes (PMNL) are recruited. In the present study we examined the effect of anti-inflammatory agents on these parameters and on bacterial clearance from the kidneys. Dexamethasone reduced interleukin-6 secretion, the PMNL response, and bacterial clearance. Diclofenac abolished the urinary interleukin-6 response but reduced the PMNL response and bacterial clearance only at the highest concentrations. Indomethacin drastically decreased bacterial clearance without the corresponding effect on interleukin-6 production or the PMNL response. The results demonstrate that the inhibition of inflammation impairs bacterial clearance from the kidneys. This is, however, not a direct function of inhibited interleukin-6 production or PMNL recruitment.
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PMID:Effects of anti-inflammatory agents on mucosal inflammation induced by infection with gram-negative bacteria. 219 56

Mast cells produce a number of cytokines including IL-6. In view of the large amounts of de novo synthesis induced by the activation of rat peritoneal mast cells and previous observations of expression of this cytokine by human lung mast cells, we have studied the regulation of IL-6 production. We examined the hypothesis that mast cell IL-6 production is not related to previous histamine release. Highly purified rat peritoneal mast cells were activated with anti-IgE, calcium ionophore A23187, or LPS. Histamine was used as a marker of preformed mediator release and IL-6 production was assessed by using the B9 hybridoma growth factor bioassay. Anti-IgE activation of rat peritoneal mast cells induced IL-6 production and histamine release. In contrast, LPS activation induced substantial, serum-dependent, IL-6 production without a significant level of histamine release. No preformed IL-6 was detected in the cells. Calcium ionophore induced histamine release from mast cells to a greater extent than did anti-IgE, but no A23187-induced IL-6 production was observed. A23187-treated cells retained high viability and produced a significant amount of TNF-alpha. To further examine the concordance of IL-6 production and histamine release we used mast cell stabilizing drugs. Dexamethasone and nedocromil significantly inhibited IL-6 production in response to anti-IgE. Our results demonstrate that there is not a direct relationship between mast cell degranulation and IL-6 production. Our observations are important for understanding the role of mast cells in inflammation and for developing strategies to modulate mast cell function in disease.
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PMID:IL-6 production by rat peritoneal mast cells is not necessarily preceded by histamine release and can be induced by bacterial lipopolysaccharide. 751 39

Supraphysiological levels of glucocorticoids, whether endogenous (Cushing's syndrome) or exogenous (glucocorticoid therapy), inhibit growth in children and immature animals. This effect has long been suspected to be due to glucocorticoid antagonism of GH action at the level of peripheral tissues. In the present study we demonstrate direct antagonism of GH action at the cellular level by the artificial glucocorticoid dexamethasone. Dexamethasone was found to inhibit the ability of GH to elicit several early events in GH signaling in 3T3-F442A fibroblasts. Dexamethasone (100 nM) for 24 h decreases by 50-75% GH-induced tyrosyl phosphorylation of mitogen-activated protein kinases ERK1 and ERK2, the transcription factor Stat3/APRF, the GH receptor-associated tyrosine kinase JAK2, and the GH receptor. These effects appear to be specific to GH. Dexamethasone does not inhibit induction of tyrosyl phosphorylation of ERK proteins by epidermal growth factor or phorbol myristate acetate, nor does it block induction of tyrosyl phosphorylation of Stat3/APRF by leukemia inhibitory factor or interleukin-6, or induction of JAK2 by leukemia inhibitory factor or interferon-gamma. Dexamethasone does not decrease the expression of ERK1 or -2, Stat3, or JAK2 proteins. Rather, the effects of dexamethasone on GH action appear to be due to a decrease in the number of GH receptors in the plasma membrane. Twenty-four-hour treatment with dexamethasone leads to a 50% decrease i GH binding, which Scatchard analysis suggests is due to a decrease in GH receptor number. These findings suggest that glucocorticoids antagonize cellular GH action by decreasing GH binding, suggesting a mechanism by which systemic glucocorticoids could antagonize GH action in peripheral tissues.
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PMID:Dexamethasone-induced antagonism of growth hormone (GH) action by down-regulation of GH binding in 3T3-F442A fibroblasts. 758 9

Pentoxifylline, a tumor necrosis factor-alpha (TNF) inhibitor, is being tested as a treatment adjunct in human immunodeficiency virus (HIV)-infected patients. However, TNF is important in cellular defense. The effect of pentoxifylline on Mycobacterium avium complex (MAC) growth in exogenously infected macrophages was compared with the effect of dexamethasone. Pentoxifylline, in a concentration that decreased MAC-induced TNF by 48.1%, enhanced MAC growth by 1.9- to 19.6-fold and 1.82- to 4.46-fold in macrophages from normal and HIV-infected patients, respectively. It also induced interleukin-6 (IL-6) in infected macrophages. IL-6 induction correlated with the increase in MAC growth (y = 0.89 + 0.266x, P = .025). Dexamethasone in an equivalent TNF-suppressing concentration also increased MAC growth but was less effective. Unlike pentoxifylline, dexamethasone suppressed IL-6 and the suppression correlated inversely with MAC growth (y = 0.248 + 9.942x, P = .003). Thus, TNF and IL-6 are important in macrophage defense against MAC. Pentoxifylline and dexamethasone should be used with caution in AIDS patients.
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PMID:Pentoxifylline impairs macrophage defense against Mycobacterium avium complex. 765 84

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