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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The transcription rate of the haptoglobin (Hp) gene is stimulated by interleukin-1 (IL-1), IL-6, and dexamethasone in rat hepatoma (H-35) cells. To identify the cis-acting regulatory elements responsive to these hormones, various lengths of 5' Hp gene-flanking regions, including the promoter, were inserted into chloramphenicol acetyltransferase gene expression vectors and transiently introduced into H-35 cells. The first 4 kb of 5' region mediated a severalfold increase in expression after treatment with IL-6 and dexamethasone. No response to IL-1 was detectable. When, however, upstream sequences were deleted to position -165 relative to the transcription start site, a significant stimulation by IL-1 was gained without appreciably affecting the IL-6 response. With the apparent removal of an inhibitory sequence, the promoter-proximal 165-bp region also displayed a severalfold enhanced response to the combination of dexamethasone, IL-1, and IL-6. The sequence from -165 to -147, termed the A-element, was found to be crucial for all hormone regulatory functions. Two copies of the A-element linked to a heterologous promoter responded to the three hormones, but to a lesser degree than in the Hp gene promoter context. The regulatory elements of the rat Hp gene were similarly active in human hepatoma cells. Optimal regulation by IL-6 in HepG2 cells was, however, independent of the A-element. The A-element functioned in these cells exclusively as an IL-1 response sequence. The results suggest that genomic sequences upstream of the rat Hp gene suppress the regulation by specific cytokines more prominently in transient expression assays than in the normal chromosomal context. Moreover, the functional comparison indicated that specific regulatory regions of the rat Hp gene do not function identically in different hepatic cell types.
Mol Cell Biol 1990 Nov
PMID:Distinct regulation of the interleukin-1 and interleukin-6 response elements of the rat haptoglobin gene in rat and human hepatoma cells. 217 89

Hepatic expression of the haptoglobin (Hp) gene in mammalian species is stimulated severalfold during an acute-phase reaction. To identify the molecular mechanism responsible for this regulation, the single-copy rat Hp gene has been isolated. The genomic sequences showed a high degree of homology with the primate Hp gene. Activity of the rat Hp gene was increased in cultured liver cells by interleukin-1 (IL-1), IL-6, and glucocorticoids. The genomic Hp gene sequence spanning from -6500 to +6500, when transiently introduced into human hepatoma (HepG2) cells, directed IL-6- and dexamethasone-stimulated expression of rat Hp mRNA and protein. No response to IL-1 was detected, suggesting that the corresponding regulatory element(s) might lie outside of the tested gene sequences. An IL-6- and dexamethasone-responsive element has been localized to the promoter proximal region -146 to -55. Although the nucleotide sequences of this rat Hp gene region showed substantial divergence from that of the human gene, analysis of sequential 5' and 3' deletion constructs indicated an arrangement of functional IL-6 response elements in the rat Hp promoter sequence comparable to that of the human homolog. The magnitude of IL-6 regulation through the rat Hp gene promoter was severalfold lower than that of the human Hp gene. The reduced activity could be ascribed to a single-base difference in an otherwise conserved sequence corresponding to an active element in the human gene. The IL-6 response of the rat Hp element was improved severalfold by substituting that base with the human nucleotide.
Mol Cell Biol 1990 Apr
PMID:Structure, hormonal regulation, and identification of the interleukin-6- and dexamethasone-responsive element of the rat haptoglobin gene. 232 5

A small portion of human lung mononuclear cells are very potent stimulators of allogeneic resting T cells. Although several-fold more effective than phagocytic alveolar macrophages (AM) and blood monocytes (Mo), they do not produce more of the lymphocyte co-stimulators interleukin-1-alpha (IL-1 alpha), interleukin-1-beta (IL-1 beta), or tumor necrosis factor-alpha (TNF-alpha) than did Mo. Blocking antibodies against IL-1 alpha, IL-1 beta, TNF-alpha, and IL-6 did not reduce T cell proliferation. These potent antigen-presenting cells (APC) are loosely adherent and do not have phagocytic inclusions. Most of them have the marker RFD1 of dendritic cells (DC) rarely present on Mo or AM and have a strong tendency to form clusters with T cells like murine DC. Thus, we demonstrate an example in the human system of a dissociation between T cell activation and IL-1 or TNF-alpha production by DC or Mo, implying a major role for other "co-stimulating signals" by lung APC with dendritic features. The presence of different APC with various co-stimulating signals may be of importance for T cell subsets modulation.
Am J Respir Cell Mol Biol 1990 Jun
PMID:Dissociation between allogeneic T cell stimulation and interleukin-1 or tumor necrosis factor production by human lung dendritic cells. 234 59

The formation of CD8+ killer cells from nonlytic thymocyte precursors is mediated by interleukin 2 and a cytokine termed CTL differentiation factor (CDF). While several reports have focused on the effects of recombinant molecules on the development of CTL, the natural protein responsible for CTL development that is produced by normal leukocytes has not been conclusively identified. A 24 kD native protein with CDF activity was enriched from leukocyte conditioned medium and neutralizing antibodies were produced. Utilizing immunoaffinity chromatography and reverse phase chromatography, we purified this CDF to homogeneity. All 21 amino acid residues at the NH2-terminus of CDF were found to be identical to that of IL-6. Natural CDF and IL-6 share many of the same biological properties, including costimulation of thymocyte proliferation with IL-1. Antibodies against CDF or IL-6 can block the activity of either cytokine, and anti-CDF blocks the activity of bulk leukocyte conditioned medium. These results indicate that IL-6 is the principal CTL differentiation factor produced by stimulated human leukocytes.
J Mol Cell Immunol 1989
PMID:Interleukin 6 is the principal cytolytic T lymphocyte differentiation factor for thymocytes in human leukocyte conditioned medium. 261 Aug 54

A synthetic DNA construct has been developed as a standard molecule whereby murine cytokine mRNA molecules can be quantified by the reverse transcription-polymerase chain reaction (RT-PCR). The construct, designated Cytoquant 1, allows the quantification of murine IL-1 alpha, IL-2, IL-3, IL-4, IL-5, IL-6, IL-10, IFN-gamma, TNF-alpha, TGF-beta, GM-CSF, CD4, CD8, HPRT and beta-actin mRNA levels. This technique is based on the amplification of a transcribed RNA molecule from Cytoquant 1 as an internal standard control in both the RT and PCR reactions. The quantification data from these analyses are expressed in absolute values, i.e. molecules/cell, which allows the data derived from separate experiments to be compared. In this study, mRNAs encoding beta-actin, IL-10, IFN-gamma and GM-CSF have been quantitated in both Th1 and Th2 cell clones with, and without, stimulation. The quantitative analysis data are highly reproducible and cytokine mRNA concentrations are reflective of restricted cytokine secretion patterns. Furthermore, constitutive cytokine mRNA levels are detectable in resting cells, eliminating the need for exogenous stimulation. The high degree of sensitivity and accuracy make this methodology uniquely suited for the study of T-cell subset cytokine expression in both in vivo and in vitro biological models.
Mol Immunol 1995 Sep
PMID:A synthetic standard DNA construct for use in quantification of murine cytokine mRNA molecules. 747 5

Interleukin (IL)-6 is a pleiotropic cytokine produced by a wide variety of cells including fibroblasts, macrophages, endothelial cells, and T and B lymphocytes. Regulated IL-6 production is an important part of normal biologic homeostasis, and abnormal IL-6 production has been associated with a large number of diseases including asthma and lung allograft rejection. Glucocorticoids are potent anti-inflammatory agents that are widely used to suppress pulmonary inflammation. To further understand the mechanisms underlying this inhibition, we determined whether glucocorticoid compounds regulate human lung fibroblast IL-6 production and characterized the mechanisms of the effects that were noted. These studies demonstrate that glucocorticoids inhibit IL-1-induced IL-6 production in a dose-dependent fashion. A greater than 95% decrease in IL-6 production was seen with 10(-6) and 10(-7) M dexamethasone, prednisolone, and hydrocortisone, and IC50 values for these agents were approximately 5 x 10(-10), 5 x 10(-9), and 10(-8) M, respectively. mRNA analysis demonstrated that these alterations in protein production were associated with proportionate decreases in IL-6 mRNA accumulation, and that this suppression of IL-6 mRNA could be reversed by the glucocorticoid receptor antagonist RU 486. Nuclear run-on studies demonstrated that glucocorticoids inhibit-IL-1-induced IL-6 gene transcription. However, the magnitude of this effect could not fully account for the potency of the glucocorticoid-induced alterations in IL-6 mRNA accumulation and protein production since 10(-6) M dexamethasone caused only a 50% decrease in IL-1-induced IL-6 gene transcription.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1994 Jun
PMID:Glucocorticoid inhibition of interleukin-1-induced interleukin-6 production by human lung fibroblasts: evidence for transcriptional and post-transcriptional regulatory mechanisms. 751 73

Hepatic expression of various members of the cytochrome P-450 (CYP) superfamily is suppressed during inflammatory responses. We have shown that the specific expression of P-450 2C11 in male rat liver is suppressed transcriptionally by endotoxin treatment. To investigate the molecular mechanisms underlying this phenomenon, we studied the effects of the inflammatory cytokines interleukin (IL)-1, IL-6, tumor necrosis factor-alpha (TNF), interferon (IFN)-alpha, and IFN-gamma on the expression of P-450 2C11 and the mRNAs of two typical acute-phase protein genes, alpha 1-acid glycoprotein (AGP) and fibrinogen, in primary hepatocyte cultures. IL-1, IL-6, TNF, and IFN-alpha all suppressed P-450 2C11 mRNA, whereas IFN-gamma had no effect. IL-1 and TNF were more effective than IL-6 in the suppression of P-450 2C11 mRNA. Whereas IL-1 and IL-6 effects on P-450 2C11 were accompanied by induction of AGP and fibrinogen mRNAs, IFN-alpha and TNF treatments had no effects on AGP. The suppression of P-450 2C11 and the induction of AGP by IL-1 showed similar time courses. The combination of IL-1 and IL-6 showed additivity in suppression of P-450 2C11, at maximally effective concentrations of cytokines. The effects of IL-1 on P-450 2C11 and AGP expression were blocked by IL-1 receptor antagonist protein. We also studied the effects of IL-1 and IL-6 on the transient expression of chloramphenicol acetyl-transferase reporter gene constructs containing 200 or 1287 base pairs of the 5' flanking region of the CYP2C11 gene, transfected into primary hepatocytes. The chloramphenicol acetyltransferase activities in cells transfected with the 200-base pair construct were reduced to about 33% and 58% of control levels by treatment with IL-1 or IL-6, respectively, suggesting that sequences important for cytokine down-regulation lie within the proximal promoter region of the CYP2C11 gene.
Mol Pharmacol 1995 May
PMID:Suppression of the constitutive expression of cytochrome P-450 2C11 by cytokines and interferons in primary cultures of rat hepatocytes: comparison with induction of acute-phase genes and demonstration that CYP2C11 promoter sequences are involved in the suppressive response to interleukins 1 and 6. 753 97

Fibronectin (Fn) and tenascin (Tn) are two major extracellular matrix glycoproteins participating in tissue morphogenesis and repair. The regulation of their synthesis and deposition during airway inflammation and their possible contribution in asthma are poorly understood. In this study, modulation of Fn and Tn production was investigated in transformed human bronchial epithelial cells in culture. The cells were treated with interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), a combination of these cytokines, interleukins 3 and 6 (IL-3 and IL-6), granulocyte macrophage-colony stimulating factor (GM-CSF), and a combination of IL-3 and IL-6 for 48 h. Immunofluorescence and immunoblotting methods with monoclonal antibodies to Fn and Tn antibodies suggested the production of some Fn and Tn in the untreated cells. Fn was minimally induced in response to IFN-gamma and TNF-alpha, when compared with the untreated cells, whereas TNF-alpha and especially the IFN-gamma plus TNF-alpha combination resulted in a prominent Tn induction. Interleukins and GM-CSF did not induce Fn or Tn in any case. These results show that human bronchial epithelial cells are capable of producing Fn and Tn. The modulation of Fn and Tn may have an important impact on the pathology of epithelial cells during airway inflammation in vivo.
Am J Respir Cell Mol Biol 1995 Jul
PMID:Modulation of fibronectin and tenascin production in human bronchial epithelial cells by inflammatory cytokines in vitro. 754 Dec 19

To evaluate the physiological role of G-CSF following surgery, we measured the serum levels of immunoreactive IL-6 and G-CSF sequentially in nine patients after major elective thoracoabdominal surgery for esophageal carcinoma. Both G-CSF and IL-6 levels reached their maxima at the first postoperative day and decreased thereafter. There was a significant correlation between serum G-CSF (y) and IL-6 (x) levels (y = 3.273x + 3.991; r = 0.787, n = 78, p < 0.001). In the case that developed aspiration pneumonia and ARDS at the second postoperative day, the measured G-CSF level was less than half the predicted value. The relationship between serum G-CSF and IL-6 levels supports the central role of G-CSF as the host defense response modifier and, thus, low G-CSF levels in the circulation is one reason for the immunodeficient state after major surgery.
Res Commun Mol Pathol Pharmacol 1995 Mar
PMID:Changes in serum granulocyte colony-stimulating factor (G-CSF) and interleukin 6 (IL-6) after surgical intervention. 754 36

The late-phase of allergic asthma is characterized by infiltration of the airway with eosinophils within 6 h of mast cell activation. Pro-eosinophilic/pro-allergic (TH2) cytokines, originally described as T-lymphocyte products, have recently been ascribed to mast cells as well. To date, however, it is unknown if TH2 cytokine gene expression by the human mast cells is subject to receptor-mediated regulation analogous to that of T-cells, and if messenger RNA (mRNA) expression results in protein secretion occurring in a temporal context consistent with the late-phase response. We examined interleukin-4 (IL-4), IL-5, and IL-6 mRNA expression induced by anti-IgE activation of human lung explants as assessed using reverse transcription/polymerase chain reaction (RT-PCR). Anti-IgE stimulation resulted in rapid and sustained upregulation of IL-5 message, but did not have analogous effects on IL-4 or IL-6. Using quantitative-competitive PCR, we demonstrated that 100 ng of total cellular RNA from human lung contained 1 fg of IL-5 mRNA; this increased to 100 fg 4 h after anti-IgE activation. The source of the anti-IgE-enhanced IL-5 mRNA is likely the mast cell itself, as anti-CD3 activation of lung led to a dissimilar array of cytokine expression. In addition, human lung mast cells purified to near homogeneity expressed IL-5 mRNA after activation, as shown by both RT-PCR and in situ hybridization. In both lung fragments and purified human lung mast cells, the modulation of IL-5 mRNA expression preceded the secretion of IL-5 protein, detected as early as 4 h after activation. Neither isolated purified mast cells nor purified peripheral blood T cells could be induced to secrete detectable amounts of IL-5 protein when activated only with antibodies against IgE or CD3-T cell receptor complex, respectively. However, mast cells (n = 4) and T cells (n = 6) cultured at comparable concentrations (4 x 10(6)/ml) activated through their respective antigen receptors in the presence of phorbol ester yielded comparable IL-5 production (253 +/- 126 pg/ml versus 183 +/- 75 pg/ml, mean +/- SE). We conclude that mast cells are analogous to T cells in the requirement of co-stimuli for the production of IL-5 protein. Moreover, the rapid kinetics of IgE-mediated IL-5 transcription and protein elaboration are consistent with a primary role for mast cell activation directly leading to late-phase airway eosinophilia.
Am J Respir Cell Mol Biol 1995 Dec
PMID:Human lung mast cell IL-5 gene and protein expression: temporal analysis of upregulation following IgE-mediated activation. 757 4


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