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

Communication between cells determines the steady-state composition of the lung in health and becomes a critical determinant of outcome in pathologic processes resulting in anatomic remodeling. This review presents the evolving concepts of the biology of cytokines (also known as peptide growth factors or biological response modifiers) in maintaining normal tissue growth and homeostasis. How these extracellular signaling proteins are involved in such pathologic disorders as spontaneous pulmonary fibrosis, sarcoidosis, pneumoconiosis, and the evolution and recovery from acute lung injury is also discussed. During the past decade the cytokines have come to the fore as important multifunctional mediators of cell behavior and cell-cell communication. A wide range of cellular responses are influenced or triggered when cytokines interact with cells. These include mitosis, chemotaxis, angiogenesis, cytoskeleton arrangement, immunomodulation, and extracellular matrix production. Cytokines influence cell behavior by binding to specific high affinity surface receptors on target cells. These receptors are linked in turn at the cell membrane to a complex array of intracellular signaling pathways. Individual cytokines may inhibit as well as promote cellular functions such as mitosis and thereby play a critical role in homeostasis of normal tissue elements. Hence, cytokines are intimately involved in normal tissue homeostasis as well as in processes eventuating in growth and remodeling. All cells produce and secrete cytokines at some time during their life. Each cytokine is capable of modulating more than one cellular function. Although produced by a variety of cell types, the triggers that induce a specific cytokine to be produced differ between cells. Many of the cytokines share regions of homologous nucleic acid sequences, suggesting that they are members of larger gene families. Given that tissues and cells are exposed to complex cytokine mixtures rather than to individual cytokines, recent attention has turned to understanding how cytokines interact. The combined effects of cytokine mixtures have proved to be both complex and unpredictable based on knowledge of the separate actions of the individual cytokines involved. In studies of the role of cytokines in lung disease, early research attention has focused on those cytokines released by alveolar macrophages (the so-called macrophage-derived growth factors). However, structural cells as well as immune effector cells of the lung are capable of cytokine production and release. The cytokines receiving the most attention to date in relation to pulmonary diseases include platelet-derived growth factor (PDGF), interleukin-1 (IL-1), transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), insulinlike growth factor I (IGF-I), and, most recently, interleukin-6 (IL-6).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cytokines of the lung. 224 Aug 51

Previous studies have shown upregulation of lung cell interleukin-6 (IL-6) production in bleomycin-induced pulmonary fibrosis. To further elucidate the regulatory mechanisms governing this disease, the effects of bleomycin on the production of the pleiotropic cytokine, IL-6, were investigated in lung endothelial cells. Rat pulmonary artery endothelial cells were treated with bleomycin at doses previously shown to be effective in upregulating cytokine production in these cells, and the conditioned media was collected and assayed for IL-6 activity. The results show that these endothelial cells constitutively produced IL-6 and that bleomycin increased the production in a time- and dose-dependent manner. Feeding rats diets deficient in n-6 fatty acids is known to ameliorate bleomycin-induced lung fibrosis. In order to examine if fatty acids could modulate IL-6 production in vitro, cells were lipid depleted and then supplemented with 18:1n-9, 18:2n-6, or 18:3n-3 fatty acids, and the effects of bleomycin on IL-6 production reexamined. This regimen resulted in significant depletion of arachidonate in the 18:1n-9 and 18:3n-3 supplemented cells, which was associated with significantly reduced IL-6 production relative to the 18:2n-6-supplemented cells, both constitutively and when stimulated with bleomycin. Preincubation with indomethacin did not significantly inhibit the production of IL-6 by all three groups of cells, nor did supplementation with a stable prostacyclin analog increase IL-6 production. These results suggest that endothelial cell IL-6 production is not directly dependent on prostacyclin or other cyclooxygenase metabolites but may require or be upregulated by 18:2n-6 and/or metabolites derived from it.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of rat pulmonary endothelial cell interleukin-6 production by bleomycin: effects of cellular fatty acid composition. 750 28

Susceptibility of mice to the induction of pulmonary fibrosis by bleomycin sulfate is inbred strain dependent, with C57BL/6 mice exhibiting high sensitivity to the drug and BALB/c mice demonstrating a resistant phenotype. The lungs of bleomycin treated C57BL/6J and BALB/cBy mice were analyzed for their mRNA expression level of a panel of cytokines using a semi-quantitative polymerase chain reaction (SQ-PCR) assay. Transforming growth factor-beta 1 (TGF-beta 1) mRNA was found to increase sevenfold by 5 days after bleomycin treatment of C57BL/6J (sensitive) mice. BALB/cBy (resistant) animals demonstrated a lower level of TGF-beta 1 mRNA induction, approximately threefold, after bleomycin administration. Analysis of interleukin-1 beta (IL-1 beta) mRNA levels also revealed a difference between the two strains, with BALB/cBy mice expressing approximately fourfold higher IL-1 beta mRNA levels than C57BL/6J mice. This result suggested possible protection by IL-1 beta. Analysis of (C57BL/6JxBALB/cBy)F1 hybrids, which are shown in this report to be sensitive to bleomycin-induced fibrosis, revealed a high IL-1 beta mRNA level, similar to that in the resistant parent. Thus, the observed strain variation in the level of IL-1 beta mRNA is not associated with differences in susceptibility to the induction of pulmonary fibrosis. In contrast, strain variation in interleukin-6 (IL-6) mRNA levels was observed that was completely concordant with the segregation of susceptibility phenotypes between the parental and F1 strains. This result indicates a possible association between sensitivity to bleomycin-induced fibrosis and inducibility of IL-6 mRNA upon drug treatment. Analysis of TGF-beta 2, interferon-gamma, interleukin-2, interleukin-3, and interleukin-4 (IL-4) mRNA showed no detectable strain variation in steady state mRNA levels in the lung as a consequence of bleomycin treatment. In contrast, the level of IL-4 receptor mRNA was induced to a higher degree in both sensitive groups (C57BL/6J and F1) than in resistant mice (BALB/cBy). Therefore, modulation of the IL-4 response, not at the level of IL-4 but through regulation of the IL-4 receptor, may play a role in pulmonary fibrogenesis.
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PMID:PCR analysis of cytokine induction profiles associated with mouse strain variation in susceptibility to pulmonary fibrosis. 769 32

The influence of peplomycin (PLM) and azelastine hydrochloride (Azeptin) on reactive oxygen (RO) and cytokine generation was examined in human peripheral blood mononuclear leukocytes, polymorphonuclear leukocytes (PMN), and rabbit alveolar macrophages (RAM). In addition, the influence of these drugs on DNA and collagen synthesis was investigated in human gingival and rabbit pulmonary fibroblasts. In vitro, PLM increased the FMLP- and PMA-induced chemiluminescence and superoxide (O2-) generation in human PMN and RAM in a dose-dependent manner. In contrast to PLM, Azeptin dose-dependently suppressed RO generation. Such contrasting actions of PLM and Azeptin were also observed in RAM and PMN obtained from rabbits treated with PLM or Azeptin. Even when human PMN were preincubated with 10-100 micrograms/ml of PLM, the increase in RO generation was negligible in the presence of 10(-5) M Azeptin in the culture medium. No increases in RO generation were observed in RAM or PMN obtained from rabbits that had received PLM (0.1 mg/kg per day) and Azeptin (0.04 mg/kg per day) concomitantly. PLM suppressed superoxide dismutase activity in RAM and human PMN, while Azeptin did not affect this activity. In vitro, PLM up-regulated the release of interleukin-1 beta, interleukin-6, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor both from human cells and from RAM and pulmonary fibroblasts. In the generation of these cytokines, Azeptin abrogated the up-regulatory action of PLM. PLM and Azeptin also had contrasting actions in [3H]thymidine and [3H]proline incorporation in human and rabbit fibroblasts. Furthermore, protein tyrosine phosphorylation, in particular that of a 115-kDa protein in human PMN, was suppressed by Azeptin and enhanced by PLM. These results seem to indicate that up-regulated RO and collagen generation are the causative factors of PLM-induced pulmonary fibrosis and that Azeptin may suppress the adverse effect.
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PMID:Contrasting influence of peplomycin and azelastine hydrochloride (Azeptin) on reactive oxygen generation in polymorphonuclear leukocytes, cytokine generation in lymphocytes, and collagen synthesis in fibroblasts. 780 82

We measured levels of cytokines and type III procollagen aminopeptides (procollagen III peptides) in bronchoalveolar lavage fluid obtained from 20 patients with stable pulmonary fibrosis (PF) and seven patients with progressive PF, and nine control subjects to determine the role of cytokines in the development of PF. Procollagen III peptide levels were markedly increased in progressive PF patients. Tumour necrosis factor-alpha, interleukin-6, transforming growth factor-beta and interferon-gamma (IFN-gamma) levels were elevated in both PF patients as compared with controls, with a tendency of higher levels in progressive patients, whereas interleukin-1 beta (IL-1 beta) level was decreased in both PF patients. When the correlation between procollagen III peptide and various cytokine levels was analysed the only significant correlation was inversely between procollagen III peptide and IFN-gamma in progressive PF patients. These results indicated that although multiple cytokines may be involved in the development of PF, the negative role of IFN-gamma in active collagen synthesis could be also important.
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PMID:Determination of various cytokines and type III procollagen aminopeptide levels in bronchoalveolar lavage fluid of the patients with pulmonary fibrosis: inverse correlation between type III procollagen aminopeptide and interferon-gamma in progressive patients. 788 35

Interleukin-6 (IL-6) is a pleiotropic cytokine having several functions, including the regulation of immunologic and inflammatory responses. It is produced by many cell types, including lymphocytes, macrophages, and fibroblasts, and is believed to play a major role in pulmonary fibrosis, a condition resulting from expansion of the fibroblast compartment and the accumulation of extracellular matrices secreted primarily by fibroblasts. Production of IL-6 by lung fibroblasts has been well documented; however, it was not known whether all murine lung fibroblasts secreted IL-6 or only subsets thereof. Previous studies in our laboratory have shown that murine lung fibroblasts can be divided into subpopulations based on Thy 1 expression. These subpopulations, Thy 1+ and Thy 1-, differ in morphology, expression of surface markers, and function. IL-6 mRNA was detected in both Thy 1+ and Thy 1- murine fibroblasts and clones using reverse transcriptase polymerase chain reaction (RT-PCR). Interestingly, semi-quantitative RT-PCR and Northern blot analysis demonstrated that IL-6 mRNA was down-regulated in confluent fibroblast cultures versus cultures in log phase growth. Also, IL-6 activity was detected in the supernatants of murine lung fibroblast lines and clones using an IL-6-dependent hybridoma assay. Hybridoma proliferation was inhibited by the addition of a neutralizing anti-mouse IL-6 antibody, indicating that the activity was indeed due to IL-6. The lung fibroblasts expressed IL-6 receptors on their surface as determined by flow cytometry using a rat anti-mouse IL-6 receptor antibody (15A7).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interleukin-6 is an autocrine growth factor for murine lung fibroblast subsets. 794 84

Pulmonary fibrosis is a frequent and serious complication of scleroderma whose pathophysiology remains poorly understood. The alveolar structures are infiltrated by activated chronic inflammatory cells, alveolar macrophages and polymorphonuclear neutrophils in particular and these could play a determining role. We have studied the state of activation of alveolar macrophages and monocytes circulating in these patients who presented with scleroderma and interstitial pulmonary involvement and also in healthy subjects. The neutrophil alveolitis observed in the patients is accompanied by a raised level of interleukin-8 secretion by the alveolar macrophages compared to the healthy subjects. Interleukin-8 is an important chemotactic molecule for polymorphonuclear neutrophils in the lung. The neutrophil alveolitis is accompanied by a breakdown in the equilibrium of elastase-antielastase which could participate in the development of alveolar lesions leading to fibrosis. In addition to the activation of macrophages, there is an activation of monocytes marked by the increase in secretion of interleukin-6 and interleukin-8 in vitro during the progression of the disease of scleroderma. Thus, alveolar inflammation is integrated with the overall systemic inflammation whose causes remain unknown.
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PMID:[Scleroderma and alveolar inflammation]. 865 Apr 11

The ancient drug colchicine has repeatedly been proposed as a novel drug for therapy of pulmonary fibrosis. The present study was undertaken to add to the knowledge on colchicine's antiinflammatory and antifibrotic properties and thus help determine its actual rank in the treatment of pulmonary fibrosis. In vitro cell culture experiments with stimulated and unstimulated normal donor peripheral blood mononuclear cells (PMNC) and a human lung fibroblast cell line (WI-38) were used to determine the effects of colchicine on PMNC cytokine release (interleukin-6 and tumor necrosis factor-alpha) as well as on fibroblast proliferation and collagen synthesis rates. Reverse transcriptase polymerase chain amplifications of alpha 1 (III) collagen were done to detect collagen messenger ribonucleic acid (mRNA) expression. Colchicine did not significantly modulate tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) release of PMNC. Colchicine inhibited fibroblast proliferation and total collagen synthesis significantly at concentrations obtainable in serum in vivo. Transcription of the alpha 1 (III) collagen gene into mRNA continued under colchicine. We conclude that colchicine is a potent in vitro inhibitor of fibroblast functions in terms of proliferation and collagen synthesis. The mechanism of collagen inhibition is more likely an inhibition of cellular collagen secretion than a switch off of collagen mRNA transcription. On the other hand, although colchicine is known to inhibit many leukocyte functions, it is a poor inhibitor of cytokines known to be important for fibrogenesis (e.g. IL-6, TNF-alpha, IL-1, platelet-derived growth factor, and transforming growth factor-beta). This makes colchicine, at least from a theoretical standpoint and as concluded from in vitro studies, a preferable candidate for a combined therapeutic strategy.
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PMID:Antiinflammatory and antifibrotic properties of colchicine: implications for idiopathic pulmonary fibrosis. 895 72

Chronic sinusitis in allergic (ACS) and nonallergic (NCS) patients is characterized by persistent inflammation and subepithelial fibrosis of the sinus mucosa. The inflammatory infiltrate is rich in T lymphocytes, monocyte/macrophages, plasma cells, and eosinophils. Th2-type cytokines are thought to regulate inflammatory cell recruitment, activation, survival, and the release of tissue-damaging mediators. Interleukin-6 is a proinflammatory Th2-type cytokine that stimulates fibroblast proliferation and collagen synthesis. Expression of interleukin-6 has been reported in pulmonary fibrosis and a number of other conditions associated with fibrotic tissue changes. In vitro studies have indicated that interleukin-6 is produced by macrophages, T cells, eosinophils, mast cells, and other cell types. Here we examined interleukin-6 messenger RNA and immunoreactivity in the sinus epithelium and subepithelium of subjects with ACS and NCS by in situ hybridization and immunocytochemistry, performed on sinus biopsy and polyp sections obtained from patients. Nasal turbinate biopsy specimens from normal volunteers were used as controls. Interleukin-6 messenger RNA and immunoreactivity were expressed by a significantly greater proportion of epithelial and subepithelial cells in ACS and NCS subjects than in normal controls. There was no difference in epithelial or subepithelial interleukin-6 expression between ACS and NCS patients. Colocalization studies revealed that macrophages, T cells, eosinophils, and mast cells are sources of interleukin-6 messenger RNA in ACS and NCS. The numbers of interleukin-6 messenger RNA-positive cells coexpressing immunoreactivity for the mast-cell marker were significantly greater in ACS than in NCS subjects. The results of this study suggest a role for interleukin-6 in the inflammatory response of chronic sinusitis.
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PMID:Interleukin-6 expression in chronic sinusitis: colocalization of gene transcripts to eosinophils, macrophages, T lymphocytes, and mast cells. 956 Jan 3

Previously, macrophage inflammatory protein-1alpha (MIP-1alpha), a member of the C-C chemokine family, has been implicated in bleomycin-induced pulmonary fibrosis, a model of the human disease idiopathic pulmonary fibrosis. Neutralization of MIP-1alpha protein with anti-MIP-1alpha antibodies significantly attenuated both mononuclear phagocyte recruitment and pulmonary fibrosis in bleomycin-challenged CBA/J mice. However, the specific stimuli for MIP-1alpha expression in the bleomycin-induced lesion have not been characterized. In this report, two mediators of the inflammatory response to bleomycin, tumor necrosis factor (TNF) and interleukin-6 (IL-6), were evaluated as putative stimuli for MIP-1alpha expression after bleomycin challenge in CBA/J mice. Elevated levels of bioactive TNF and IL-6 were detected in bronchoalveolar lavage (BAL) fluid and lung homogenates from bleomycin-treated CBA/J mice at time points post-bleomycin challenge, which precede MIP-1alpha protein expression. Treatment of bleomycin-challenged mice with soluble TNF receptor (sTNFr) or anti-IL-6 antibodies significantly decreased MIP-1alpha protein expression in the lungs. Furthermore, normal alveolar macrophages secreted elevated levels of MIP-1alpha protein in response to treatment with TNF plus IL-6 or bleomycin plus IL-6, but not TNF, bleomycin, or IL-6 alone. Finally, leukocytes recovered from the BAL fluid of bleomycin-challenged mice secreted higher levels of MIP-1alpha protein, compared to controls, when treated with TNF alone. Based on the data presented here, we propose that TNF and IL-6 are part of a cytokine network that modulates MIP-1alpha protein expression in the profibrotic inflammatory lesion during the response to intratracheal bleomycin challenge.
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PMID:TNF and IL-6 mediate MIP-1alpha expression in bleomycin-induced lung injury. 976 34


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