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

Ethanol alters many metabolic processes within the liver. Both ethanol abuse and the inability to mount an acute phase response (APR) have been associated with an increased morbidity and mortality in critically ill patients. To determine if ethanol influences the hepatic APR, relative amounts of two different human acute phase protein mRNA's were examined in the human hepatoma cell line Hep 3B before and after exposure to ethanol. Hep 3B cells were treated with one or more of the following: ethanol ((E) 150 mM); interleukin-1 beta ((IL-1) 200 units/ml); or interleukin-6 ((IL-6) 50 units/ml). After a 12-20 hr incubation relative amounts of mRNA for a1-protease inhibitor (PI) or beta fibrinogen were determined by Northern blot hybridization. Both ethanol and IL-6 were found to induce a1-PI mRNA. Fibrinogen mRNA was induced by IL-6 but not by ethanol, and no induction of PI or fibrinogen mRNA was found with IL-1. This suggests that under certain conditions, ethanol may influence acute phase protein metabolism. To our knowledge, this is the first description of an ethanol induced alteration of acute phase protein mRNA.
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PMID:Ethanol induces a1-protease inhibitor mRNA in Hep 3B cells. 165 92

Cultured human neuronal (SH-SY5Y neuroblastoma) cells synthesize and secrete the potent protease inhibitor alpha 2-macroglobulin (a2M) upon stimulation with interleukin-6 (IL-6) indicating that alpha 2-macroglobulin behaves as an acute-phase protein in the human central nervous system. Exogenous addition of a2M to the cultured neuronal cells resulted in only a slight inhibition of Alzheimer beta A4-amyloid precursor protein (APP) synthesis, but markedly inhibited its secretion pointing to the possibility that a2M may affect the proteolytic APP processing. Evidence is provided that IL-6 and a2M are involved in Alzheimer's disease pathogenesis.
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PMID:Alpha 2-macroglobulin synthesis in interleukin-6-stimulated human neuronal (SH-SY5Y neuroblastoma) cells. Potential significance for the processing of Alzheimer beta-amyloid precursor protein. 170 16

We have previously shown that changes in acute-phase protein glycosylation result from alterations occurring within hepatocytes as a result of regulation by cytokines, that the glycosylation patterns of proteins secreted by Hep 3B and Hep G2 cells respond differently to the crude mixtures of cytokines found in conditioned medium from LPS-stimulated monocytes, and that interleukin-6 (IL-6) causes increased concanavalin A (Con A) binding of alpha 1 protease inhibitor in Hep 3B cells and decreased Con A binding of this protein in Hep G2 cells. In the present study we found that transforming growth factor beta 1 (TGF-beta), like IL-6, led to secretion of forms of alpha 1-protease inhibitor with increased Con A binding in Hep 3B cells, and that IL-6 and TGF-beta in combination were additive. In contrast, in Hep G2 cells, TGF-beta had an effect opposite to that produced by IL-6, leading to secretion of forms of alpha 1-protease inhibitor with increased Con A binding. When employed in combination with IL-6. TGF-beta abolished the effect of that cytokine. These studies indicate that TGF-beta influences glycosylation of alpha 1-protease inhibitor in two human hepatoma cell lines in a manner that can be differentiated from that of IL-6. The identification of TGF-beta as a second defined cytokine capable of influencing glycoprotein glycosylation and the demonstration that the effect of one cytokine can be modulated by another cytokine support the view that changes in glycosylation of plasma proteins are mediated by combinations of cytokines.
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PMID:Transforming growth factor beta 1 influences glycosylation of alpha 1-protease inhibitor in human hepatoma cell lines. 217 6

The relation between interleukin-6 (IL-6) levels and changes in serum concentrations and glycosylation (concanavalin A affinity) of two human acute-phase glycoproteins, alpha 1-acid glycoprotein (AGP) and alpha 1-protease inhibitor (PI), was studied in sequential serum samples of burn patients. The level of IL-6 was already increased at the first day following injury, and after a dip at day 2 or 3 rapidly reached a second maximal value at day 4 or 5. The serum concentrations of AGP and PI reached their maximal values after day 5 and remained at a high level throughout the total period studied (7 weeks). The concanavalin A reactivities of both acute-phase glycoproteins were found to be elevated only during the first 2-2.5 weeks. Maximal values were observed on day 2 and from day 7 to 16, following closely the rise and fall of the IL-6 serum level. After day 16, the concanavalin A affinity rapidly declined long before a decrease was observed in the serum concentrations of AGP and PI. Our previous in vitro studies have indicated an involvement of IL-6 in the induction of both secretion and increased concanavalin A affinity. This study indicates that IL-6 could play a causal role in the induction of both phenomena in vivo.
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PMID:Changes in the serum concentration and the glycosylation of human alpha 1-acid glycoprotein and alpha 1-protease inhibitor in severely burned persons: relation to interleukin-6 levels. 226 95

alpha 2-Macroglobulin (alpha 2M) is a broad spectrum protease inhibitor associated with inflammatory responses and proposed to be important in tissue remodeling. alpha 2 M also functions as a carrier of specific growth factors and cytokines, including platelet-derived growth factor, transforming growth factor-beta, basic fibroblast growth factor, interleukin-1, interleukin-6. To determine whether alpha 2M is associated with remodeling phenomena in the rat ovary, the expression of alpha 2M mRNA and protein has been analyzed in specific ovarian cell types during ovulation, luteinization, and luteolysis. Before ovulation, alpha 2M mRNA is not detectable in granulosa cells. Twelve hours after injection of an ovulatory dose of hCG a 5.2-kilobase alpha 2M mRNA is detectable in luteinizing follicles, which is increased further by 48 h and maintained in corpora lutea (CL) for up to 96 h. Administration of PRL from 24-96 h results in both inhibition of luteolysis and marked increases in alpha 2M mRNA in CL, but not in residual tissues, of these same ovaries, isolated 48, 72, and 96 h after an ovulatory dose of hCG, alpha 2M mRNA is also induced by PRL in cultures of luteinized granulosa cells. These changes in alpha 2M mRNA in follicles or developing CL do not appear to reflect the amount of alpha 2M protein present: alpha 2M protein (188K monomer) is present (immunoblot and immunofluorescence data) in small antral and preovulatory follicles even though mRNA is not detectable; after an ovulatory dose of hCG the protein level transiently increases by 12 h (approximately 5-fold) and declines thereafter through 96 h; the decrease in alpha 2M protein observed at 48-96 h is delayed but not abolished by treatment with PRL, even though the mRNA levels continue to rise during this same time period. In contrast, changes in alpha 2M mRNA and protein are regulated coordinately in CL of pregnant rats. alpha 2M mRNA is present, but in low concentration, from days 4-11 of gestation, increases markedly between days 11-21, and decreases at parturition, when functional luteolysis occurs. Hysterectomy of day 10 pregnant rats combined with hormone replacement determined that alpha 2M mRNA levels are regulated primarily by PRL through day 12 and by placental lactogens during midgestation (days 12-15). The increase in alpha 2M mRNA during pregnancy precedes the 40-fold increase (peak) in a alpha 2M protein observed on day 15, which remains elevated through day 21.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hormonal regulation and tissue-specific localization of alpha 2-macroglobulin in rat ovarian follicles and corpora lutea. 247 32

Most attacks of acute pancreatitis are mild and self-limiting. In 10-20% of the cases, however, severe disease with multiple systemic complications develops. During the last few years it has been recognized that activated leukocytes have an important role in the multisystem involvement during acute pancreatitis. Activated leukocytes are thus a pathogenetic factor in the severity of the disease. Activation of polymorphonuclear granulocytes (PMNs) and of monocytes/macrophages is an early event during severe acute pancreatitis. Factors released by activated leukocytes therefore reflect the severity of the disease. Three independent studies have shown that released PMN-elastase is a reliable early prognostic marker that permits correct classification of 80-95% of the patients within the first 24-48 hours. Interleukin-6 (IL-6), mainly secreted by activated monocytes/macrophages, is also an early prognostic parameter (shown in one study), but is not superior to PMN-elastase. Leukocyte activation markers are more reliable than multiple scoring systems in the assessment of the severity of acute pancreatitis. Compared with PMN-elastase or IL-6, increased plasma concentrations of such acute-phase proteins as alpha-1-antitrypsin or CRP, and consumption of the protease inhibitor alpha-2-macroglobulin, are later events that can be detected only 1 to 4 days later. Comparison of the various inflammatory parameters suggests that PMN-elastase is the best early and reliable prognostic marker in acute pancreatitis. The reviewed data underscore the role of activated leukocytes in the pathogenesis of complicated acute pancreatitis.
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PMID:Inflammatory mediators and cytokines--new aspects of the pathophysiology and assessment of severity of acute pancreatitis? 750 68

The alpha 2-macroglobulin (alpha 2M), a protease inhibitor, is a major acute-phase protein in rats, and is produced in the liver during acute inflammation. Recently, it has been demonstrated that alpha 2M is also produced by cultured astrocytes from newborn rat brain and has neurite-promoting activity. Here, we found that the expression of the alpha 2M gene was significantly enhanced in the brain following intraperitoneal injection of the neurotoxicant, kainic acid (KA), suggesting that alpha 2M acts as an acute-phase protein in the brain, as in the case of the liver, and may be involved in neural repair processes. Expression of alpha 2M in cultured astrocytes was shown to be stimulated by interleukin-6 (IL-6) and/or leukemia inhibitory factor (LIF) in the presence of glucocorticoid. The amount of mRNAs for IL-6 and LIF increased in the brain of KA-injected rats prior to alpha 2M induction. These results strongly suggested that IL-6 and LIF are involved in alpha 2M induction in the brain, as in the case of the liver. Analysis of the cis-acting element(s) and the trans-acting factor(s) suggested that the regulatory mechanism for alpha 2M expression in astrocytes was similar to that in inflamed liver.
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PMID:Expression of the alpha 2-macroglobulin-encoding gene in rat brain and cultured astrocytes. 751 38

Human promonocytic U937 cells have previously been shown to possess at their cell surface specific transmembrane serine proteases and N-terminal amino acid proteases as well as associated enzymes including elastase and cathepsin G. In this study, purified plasma membranes from U937 cells are reported to degrade the recombinant 21-kDa 125I-interleukin-6 (125I-IL-6) into 8-kDa products with loss of biological activity, as monitored by polyacrylamide gel electrophoresis and a cell-proliferation bioassay. Degradation of 125I-IL-6 by plasma membranes was completely prevented by the serine-protease inhibitor diisopropyl fluorophosphate, but was only partially impaired by alpha 1-protease inhibitor and antibody against cathepsin G. A similar incubation of 125I-IL-6 with cathepsin G purified from U937 cells caused hydrolysis of the cytokine into similar inactive 8-kDa fragments, whereas incubation with purified U937 cell elastase failed to degrade the peptide. These findings indicate that U937 cells hydrolyze IL-6 using cell-associated serine-protease activity and that cathepsin G partially participates in this degradation. Prolonged incubation of 8-kDa 125I-IL-6 fragments with purified U937 plasma membranes, led to a complete loss of IL-6 activity related to the transformation of the 8-kDa forms into a higher-molecular-mass complex (16 kDa). This complex was stable in SDS and 2-mercaptoethanol at 100 degrees C and was not dissociated by hydroxylamine treatment, indicating the formation of a covalent non-ester bond between the 8-kDa 125I-IL-6-derived peptide and an undetermined acceptor. An initial oxidative treatment of 125I-IL-6 partially prevented complex formation, suggesting the presence of one or more oxidizable methionine residues at the binding site of 8-kDa 125I-IL-6 peptide. The kinetics of complex formation (time dependence and plasma-membrane-concentration dependence), as well as its inhibition by a specific inhibitor of N-amino-peptidase activity, bestatin, suggest the participation of peptidyl-transferase activity in complex formation. Finally, a plasma-membrane fraction, corresponding to a molecular mass > or = 30 kDa, was able to convert the 8-kDa 125I-IL-6 forms into the 125I-labeled 16-kDa complex, suggesting that a > or = 30-kDa peptidyl-transferase enzyme catalyzes the reaction and provides the 125I-labeled 16-kDa peptide by dimerization of 8-kDa 125I-IL-6-derived intermediates. Further identification of the plasma-membrane-associated peptidyl transferase as a regulator of IL-6 proteolysis may be of physiological relevance for the control of IL-6 biological activity.
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PMID:Inactivation of interleukin-6 in vitro by monoblastic U937 cell plasma membranes involves both protease and peptidyl-transferase activities. 835 88

alpha 1-Antitrypsin (alpha 1-AT) and alpha 1-antichymotrypsin (alpha 1-ACHY) are closely related protease inhibitors, synthesized primarily by the liver, which play major roles in modulation of the inflammatory response. Previously, we had shown that MCF-7 human breast cancer cells were able to synthesize active alpha 1-AT and alpha 1-ACHY and that the synthesis of both inhibitors varied among different MCF-7 sublines. We now show that when MCF-7(ML) cells (a subline synthesizing low levels of alpha 1-AT) are grown in soft agar in medium depleted of its trypsin inhibitory capacity (i.e. alpha 1-AT-free), addition of alpha 1-AT (50 micrograms/ml) significantly reduces colony formation in both the presence and absence of estradiol (34% and 44%, respectively). Under these conditions, incubation with 10(-7) M estradiol alone increased colony formation 2- to 3-fold. Colony formation was also significantly reduced by serum leukocyte protease inhibitor, which, like alpha 1-AT, is a potent inhibitor of elastase-like enzymes. We also found that a variety of inflammatory mediators, cytokines, and steroid hormones are able to stimulate synthesis of alpha 1-AT and alpha 1-ACHY by MCF-7 cells. Stimulation by interleukin-6 (IL-6; 200 U/ml), epidermal growth factor (4 nM), and estradiol (10(-7) M) was 2- to 3-fold, whereas stimulations by tetradecanoylphorbol-13-acetate (TPA; 80 nM) and IL-1 (10 U/ml) were 2- to 5-fold and 5- to 10-fold, respectively. In each instance, protein synthesis, monitored by immunoprecipitation of 35S-labeled proteins followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and steady state mRNA levels, monitored by Northern blot analysis with specific cDNA probes, increased to the same extent. Consistent with their ability to stimulate alpha 1-AT synthesis, TPA and IL-1 reduced colony formation in the absence of estradiol by 65% and 63%, respectively. In addition, the effects of both TPA and IL-1 could be reversed by antibody to alpha 1-AT. These results suggest that local synthesis of alpha 1-AT and possibly other protease inhibitors may be important in regulating the tumorigenic potential of MCF-7 breast cancer cells.
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PMID:alpha 1-Antitrypsin- and anchorage-independent growth of MCF-7 breast cancer cells. 836 78


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