Gene/Protein Disease Symptom Drug Enzyme Compound
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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) induces changes in gene expression and the N-glycosylation pattern of acute-phase proteins in hepatocytes. IL-6 exerts its action via a cell surface receptor complex consisting of an 80 kDa IL-6 binding protein (gp80) and a 130 kDa glycoprotein (gp130) involved in signal transduction. A genetically engineered gp80-derived soluble human IL-6-receptor (shIL-6-R) significantly enhanced the IL-6 effect on N-glycosylation changes (revealed by reactivity with the lectin-concanavalin A) of a1-protease inhibitor (PI) secreted by human hepatoma cells (HepG2). Stable transfection of IL-6-cDNA into HepG2 cells (HepG2-IL-6) resulting in constitutive secretion of 2 micrograms of IL-6 per 10(6) cells in 24 h led to a down-regulation of surface-bound gp80 and subsequent homologous desensitization of HepG2-IL-6 cells towards IL-6. Soluble human IL-6-R functionally substituted membrane-bound gp80 resulting in a reconstitution of responsiveness of HepG2-IL-6 cells.
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PMID:Soluble human interleukin-6-receptor modulates interleukin-6-dependent N-glycosylation of alpha 1-protease inhibitor secreted by HepG2 cells. 132 38

Polymorphonuclear leukocytes (PMN) are known to be activated by several lymphokines and can be induced to release lysosomal enzymes, prostaglandins (PG), thromboxanes (TX) and lipoxygenase products that may be involved in PMN aggregation responses during inflammatory reactions. Granulocyte-macrophage colony stimulating factor (GM-CSF), a glycoprotein cytokine released by immunocompetent cells, has been found to prime neutrophil responses, such as increased cell aggregation after exposure to various biological stimulants. In this study, we examined the effects of the cytokine GM-CSF on human neutrophilic aggregation stimulated by N-formyl-methionyl-leucyl-phenylalanine (FMLP) and its influence on the production of various arachidonic acid metabolites. Neutrophil aggregation of purified PMNs was measured by the percent change in light transmission in a standard aggregometer, and the arachidonic acid products leukotriene B4 (LTB4) and thromboxane A2 (TXA2) were quantified by radioimmunoassay. We found that GM-CSF and other cytokines, used alone, did not cause any significant increase in aggregation of the PMN. However, prior exposure of PMN to GM-CSF markedly increased the aggregation induced by FMLP as opposed to that detected with PMN stimulated with only FMLP. This priming effect was not observed with PMN preincubated with interleukin-1 (IL-1), tumor necrosis factor (TNF) or interleukin-6 (IL-6). In addition, GM-CSF and IL-6 both failed to stimulate the production of LTB4 and TXA2, products which are known to induce PMN aggregation. These findings provide new evidence suggesting that GM-CSF facilitates the action of FMLP on the adhesion dependent cellular functions of the inflammatory response, serving as an important co-factor in neutrophil aggregation.
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PMID:Granulocyte-macrophage colony stimulating factor potentiates human polymorphonuclear leukocyte aggregation responses to formyl-methionyl-leucyl-phenylalanine. 132 27

The kinetics of cytokine release and acute-phase protein gene expression in liver were investigated in rats receiving a single intraperitoneal bolus dose of Escherichia coli lipopolysaccharide (LPS). Transient elevation of plasma tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were detected. Hepatic messenger RNAs for two acute-phase proteins, alpha 1-acid glycoprotein and alpha 2-macroglobulin, were measured by Northern blotting and were found to increase to a maximum at 24 h, returning to normal by 72 h; plasma concentrations showed a slower but more sustained rise. For albumin, hepatic mRNA was reduced, being minimum at 24 h with a similar but more prolonged fall in plasma concentration. Pretreatment of rats with TNF-alpha monoclonal antibody 4 h before LPS ameliorated weight loss and anorexia, partially suppressed the rise in IL-6 and reduced the increase in hepatic mRNA and plasma concentrations of alpha 1-acid glycoprotein and alpha 2-macroglobulin. For albumin, however, such pretreatment had no effect on the fall in either hepatic mRNA or plasma concentration. Thus we have defined an in vivo role of TNF-alpha in the control of endotoxin-induced acute-phase protein generation.
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PMID:Kinetics of endotoxin-induced acute-phase protein gene expression and its modulation by TNF-alpha monoclonal antibody. 137 42

The usefulness of in situ hybridization for detecting mRNA encoding various kinds of proteins in megakaryocytic cell lines (K562, HEL and CMK) was examined. Using in situ hybridization, glycoprotein (GP) IIIa mRNA was found to be present in K562, HEL and CMK cells. Both GPIb and GPIIb mRNA were also present in HEL and CMK cells, while only HEL cells expressed platelet factor 4 mRNA. These findings were identical to those obtained with Northern blotting. It should be emphasized that in situ hybridization was useful to clearly define each cell expressing platelet specific protein mRNA. The expression of interleukin-6 (IL-6) and IL-6 receptor mRNA in mononuclear cells prepared from bone marrow aspirates was examined. In situ hybridization study demonstrated the presence of IL-6 receptor mRNA in the recognized megakaryocytes only, while IL-6 mRNA was found to be present in the megakaryocytes and a few mononuclear cells. These findings suggest that differentiation and proliferation of normal megakaryocytes might be controlled by an IL-6 autocrine loop, and detection of IL-6 receptor mRNA might be useful to identify megakaryocytes.
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PMID:[Detection of mRNA in megakaryocytes using in situ hybridization]. 140 57

Due to the stress imposed by the process of bone marrow transplantation (BMT), we hypothesized that individuals receiving such a transplant underwent an acute phase response (APR). Circulating levels of C-reactive protein (CRP), haptoglobin (HAP), alpha-1 acid glycoprotein (AAG), ceruloplasmin (CER), zinc (Zn), copper (Cu), interleukin-6 (IL-6), albumin (ALB), and thyroxine-binding prealbumin (TBPA), were measured at baseline (Day -7), Day -4, Day 0 (Transplant Day), Day +2, +7, and weekly until day 28 in 14 adults receiving an autologous bone marrow transplant as Phase 1 treatment for various hematologic or solid tumor malignancies. Ten of 14 recipients survived, 9 of which had a significant increase in CRP (p = 0.012), HAP (p = 0.011), AAG (p = 0.002), and decrease in ALB (p = 0.002) and TBPA (p = 0.004) on Day +7, but not Day 0, after bone marrow reinfusion. These findings document the presence of an APR and suggest that the bone marrow transplant process (post reinfusion) initiates a stress response in the recipient.
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PMID:The acute phase response in autologous bone marrow transplantation. 147 99

The effects of 2-deoxy-2-fluoro-D-galactose (dGalF) on N- and O-glycosylation of proteins was studied in rat hepatocyte primary cultures and in human monocytes. In hepatocytes, dGalF at concentrations of 1 mM or higher completely inhibited N-glycosylation of alpha 1-antitrypsin and alpha 1-acid glycoprotein, whereas 4 mM-2-deoxy-D-galactose (dGal) only slightly impaired N-glycosylation. In monocytes, 1 mM- or 4 mM-dGalF blocked N-glycosylation of alpha 1-antitrypsin and of interleukin-6, while O-glycosylation of interleukin-6 remained unaffected. In monocytes, dGal had no effect on protein N-glycosylation. Addition of uridine effectively prevented the UTP deficiency induced by dGalF, but had no effect on the inhibition of protein N-glycosylation by dGalF. Using 19F-n.m.r. spectroscopy, 2-deoxy-2-fluoro-D-galactose 1-phosphate (dGalF-1-P), UDP-dGalF and UDP-dGlcF could be identified as the major metabolites of dGalF in hepatocytes as well as in monocytes. In conclusion, compared with dGal, dGalF is a more efficient inhibitor of protein N-glycosylation. The effect is not caused by the depletion of UTP induced by dGalF, but rather by metabolites of dGalF. dGalF is metabolized not only in hepatocytes but also in peripheral blood monocytes, which can be used for ex vivo studies of disturbances in D-galactose metabolism.
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PMID:Inhibition of protein N-glycosylation by 2-deoxy-2-fluoro-D-galactose. 149 19

Interleukin-6 (hepatocyte stimulating factor) is a 26 kd cytokine that plays a major role in the acute phase response, especially the hepatic aspects of the acute phase response. Patients with alcoholic hepatitis manifest many aspects of the acute phase response. In this 6-month study we evaluated serial plasma interleukin-6 levels in 30 consecutive patients with moderate to severe alcoholic hepatitis. Mean admission plasma interleukin-6 activity was markedly increased (49.8 +/- 8.5 U/ml, normal less than 5 U/ml) in patients with alcoholic hepatitis, and levels decreased with clinical improvement to 15.6 +/- 6.1 U/ml at 6 months. Admission interleukin-6 activity correlated significantly (r = 0.82) with the severity of liver disease as assessed by the discriminant function of Maddrey. Also measured were selected assays postulated to be regulated by interleukin-6, including serum albumin (2.3 +/- 0.1 gm/dl), which was significantly depressed; alpha 1-acid glycoprotein (52 +/- 5 mg/dl), which was within normal limits; and IgA (827 +/- 70 mg/dl) and C-reactive protein (3.03 +/- 0.51 mg/dl), which were significantly elevated. Interleukin-6 activity fell over time in a pattern similar to that of bilirubin and C-reactive protein. We suggest that plasma interleukin-6 may not only regulate many aspects of the acute phase response but also may be a marker of inflammation and severity of disease in alcoholic hepatitis.
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PMID:Increased plasma interleukin-6 concentrations in alcoholic hepatitis. 158 11

Intravenous treatment of male rats with recombinant human interleukin-6 (rhIL6) at 50, 100 and 200 micrograms/kg (corresponding to 4, 8 and 16 x 10(4) U/animal, respectively) reduced the activities of hepatic microsomal cytochrome P450-dependent monoxygenases to varying degrees. Ethylmorphine-N-demethylase activity fell to 53% of control values, an effect similar to that induced by 2.5 mg/kg Escherichia coli lipopolysaccharide (LPS). Ethoxycoumarin-O-deethylase activity was also sensitive to inhibition, whereas IL6 had little effect on the activities of other P450-dependent enzymes, including ethoxyresorufin-O-deethylase. Pentoxyresorufin dealkylase activity, which is representative of the cytochrome P450 IIB 1/2 subfamily, was unaffected by IL6 whereas LPS reduced it to 33.7% of control values. Another hepatocyte-related parameter, serum concentration of alpha 1-acid glycoprotein (AGP), was increased by up to 3.5-fold over baseline by IL6 and 10-fold by LPS. Recombinant human interleukin-1 beta (rhIL1 beta) (10 micrograms/kg, corresponding to 5 x 10(4) U/rat) and recombinant human tumor necrosis factor alpha (rhTNF) (150 micrograms/kg corresponding to 24 x 10(4) U/rat) were both as potent as LPS (2.5 mg/kg) in increasing serum AGP levels and reducing hepatic microsomal monoxygenase activities. IL6 did not potentiate the effects of rhIL1 beta. Hepatic microsomal glucuronyltransferase activities were little affected by LPS and unaffected by rhIL6. Finally, rhIL6 was more potent after i.p. injection than after i.v. or s.c. injection. These results suggest that the effects of LPS, TNF and IL1 on the mixed-function oxidase system in vivo may be due partly to an induction of IL6 in vivo. The different sensitivities of the enzymes to IL6 but not to IL1 or TNF may be due to the involvement of two distinct mechanisms.
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PMID:Effects of interleukin-6 on cytochrome P450-dependent mixed-function oxidases in the rat. 163 28

Interleukin-6 (IL-6) is a pleiotropic cytokine exerting many immunological and non immunological actions. The cytokine binds to a specific receptor, whose activation induces the association with a novel transducer, the glycoprotein gp 130. Here we present our results about the effect of IL-6 on both hormone secretion and second messenger systems at pituitary level, and the production of IL-6 from cells of central nervous system. IL-6 inhibited basal, VIP and TRH-stimulated prolactin (PRL) secretion from single lactotropes, studied by means of reverse hemolytic plaque assay, whereas in primary cultures of anterior pituitary cells, according to the literature, the cytokine stimulated prolactin secretion. IL-6 did not affect basal adenylate cyclase activity, inositol phosphate production, and cytosolic calcium concentration. Conversely, the preincubation of pituitary cells with interleukin-6 for 20 min significantly reduced VIP- and forskolin-stimulated adenylate cyclase activity, as well as inositol phosphate production and free cytosolic calcium increase induced by TRH.
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PMID:Role of interleukin-6 in the neuroendocrine system. 166 73

Four plasma proteins, referred to as positive acute phase proteins because of increases in concentration following inflammatory stimuli, are reviewed: C-reactive protein (CRP), serum amyloid A protein (SAA), alpha 1-acid glycoprotein (AAG), and fibrinogen. The CRP and SAA may increase in concentration as much as 1000-fold, the AAG and fibrinogen approximately twofold to fourfold. All are synthesized mainly in the liver, but each may be produced in a number of extrahepatic sites. The role of cytokines in induction of the acute phase proteins is discussed, particularly the multiple functional capabilities of interleukin-6 (IL-6). Other cytokines that regulate acute phase gene expression and protein synthesis include IL-1, tumor necrosis factor alpha, interferon gamma, as well as other stimulatory factors and cofactors. The physicochemical characteristics of each protein are reviewed together with the molecular biology. For each protein, the known biological effects are detailed. The following functions for CRP have been described: reaction with cell surface receptors resulting in opsonization, enhanced phagocytosis, and passive protection; activation of the classical complement pathway; scavenger for chromatin fragments; inhibition of growth and/or metastases of tumor cells; modulation of polymorphonuclear function; and a few additional diverse activities. The role of plasma SAA is described as a precursor of protein AA in secondary amyloidosis; other functions are speculative. AAG may play an immunoregulatory role as well as a role in binding a number of diverse drugs. In addition to clot formation, new data are described for binding of fibrinogen and fibrin to complement receptor type 3. Finally, the concentration of each protein is discussed in a wide variety of noninfectious and infectious disease states, particularly in connective tissue diseases. The quantification of the proteins during the course of various acute and chronic inflammatory disorders is useful in diagnosis, therapy, and in some cases, prognosis.
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PMID:Properties of four acute phase proteins: C-reactive protein, serum amyloid A protein, alpha 1-acid glycoprotein, and fibrinogen. 170 51


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