Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10145 (IL-8)
 23,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Free radicals and reactive oxygen species can damage cells and tissues of biological organisms. Due to the fact that these compounds are generated continuously in living cells defense mechanisms must exist. This so-called antioxidative system ensures that the formation of free radicals during different physiological processes does not result in cellular damage. Free radicals (oxidants) are produced form the immune system. The purpose of this immune cell products is to destroy invading organisms and damaged tissue. Oxidants enhance IL-1, IL-8 and TNF production in response to inflammatory stimuli. Sophisticated antioxidant defense systems like enzymes or vitamins protect directly and indirectly the host against the damaging influence of oxidants. While endogenous systems can hardly be influenced, exogenous antioxidants, delivered by the diet, can be upregulated in the body. By this way the pro-/antioxidative capacity can be balanced or even unbalanced.
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PMID:[Antioxidants in nutrition and their importance in the anti-/oxidative balance in the immune system]. 853 Jan 28

The purpose of these studies was to examine the sensitivity of the PIP 2-PLC-transducing pathway (GPLC) and its relationship to the respiratory burst in human polymorphonuclear leukocytes (PMN) stimulated by IL-8, TNF-alpha, or IL-1 beta during sequential changes in buffer oxygen tension from normoxia (pO2 = 180-200 mm Hg), to hypoxia (pO2 < 30 mm Hg) and then reoxygenation (pO2 > 140 mm Hg). Our specific hypothesis was that altered oxygen tensions would regulate the G PLC pathway in human PMN. G PLC activity was assayed by investigating phospholipase C activity by measuring inositol phosphates and diacylglycerol (DAG) formation. Respiratory burst activity was assayed as O 2 production and NADPH oxidase activation in intact PMN and in a cell-free system, respectively, and correlated separately to both early and late DAG production. At 1 min, DAG formation during normoxia was decreased by IL-8 plus fibronectin while hypoxia had no regulatory effect on control of DAG formation by any of the cytokines. In contrast to early DAG formation, hypoxia significantly downregulated late DAG formation induced by buffer without fibronectin, IL-8 plus fibronectin, and IL-1 beta with or without fibronectin. Hypoxia/reoxygenation in and of itself significantly increased DAG formation vs levels seen in the presence or absence of IL-8, TNF-alpha, or IL-1 beta with or without fibronectin. Changes in early DAG production during the alterations in oxygen tension correlated best with corresponding changes in O 2 production in intact cells, whereas late DAG production correlated best with NADPH oxidase activation assayed in the cell-free system. Thus, changes in oxygen tension can directly modulate the extent of the PMN response to stimulation by IL-8, TNF-alpha, or IL-1 beta and the G PLC-receptor pathway is particularly regulated by physiologically relevant periods of hypoxia/reoxygenation.
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PMID:Altered oxygen tension modulates cytokine-induced signal transduction in polymorphonuclear leukocytes: regulation of the G PLC pathway. 860 6

Reactive oxygen intermediates (ROI), reactive nitrogen intermediates (RNI), and cytokines are frequent companions at sites of acute inflammation. Previous work has established a clear link between the production of cytokines and the subsequent generation of ROI and RNI. However, more recent data indicates that ROI and RNI not only serve as end-stage effector molecules of pathogen destruction and tissue injury, but also as initiators of acute inflammation. Specifically, ROI and RNI will upregulate cytokine gene expression since antioxidants inhibit interleukin 8 (IL-8) production and do not decrease production of other cytokines. Treatment with hydroxyl radical scavengers such as dimethyl sulfoxide (DMSO) will decrease the production of IL-8 in stimulated human whole blood, fibroblasts, type II epithelial cells, and hepatoma cells, but not other cytokines. Addition of exogenous ROI will increase IL-8 production in these same cells. Inhibition of nitric oxide synthase will decrease production of IL-8, whereas addition of nitric oxide (NO)-generating compounds will increase production of IL-8. The hydroxyl radical appears to be the final common pathway of cell activation for IL-8 synthesis, since DMSO will inhibit the NO-driven production of IL-8. Our data indicate that ROI and RNI can serve as intracellular second messengers to induce IL-8 gene expression.
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PMID:Regulation of cytokine gene expression by reactive oxygen and reactive nitrogen intermediates. 861 91

We investigated the effect of alterations in buffer oxygen tensions from normoxia (PO2 = 180-200 mm/Hg) to hypoxia (PO2 < 30 mm/HG) and then reoxygenation (PO2 > 140 mmHg) on the GPLD-pathway by measuring phosphatidylethanol formation in the presence of ethanol and subsequent NADPH oxidase activation and O2-production in polymorphonuclear leukocytes (PMN). Experiments were performed with PMN stimulated with either interleukin (IL)-8, tumor necrosis factor (TNF)-alpha, or IL-1 beta in the presence or absence of fibronectin. Hypoxia exerted a downregulating effect on this pathway and reoxygenation restored GPLD activation to levels seen during normoxia; however, supraphysiological concentrations of cytokines were able to reverse this pattern. Changes in GPLD activation correlated best with changes in O2-production during the hypoxia to hypoxia/reoxygenation transition induced by TNF-alpha-Fn and IL-1 beta +/- Fn. Thus, changes in oxygen tension can directly modulate the extent of the PMN response to stimulation by IL-8, TNF-alpha, or IL-1 beta, and activation of the GPLD-pathway appears to be highly sensitive to hypoxia and hypoxia/reoxygenation.
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PMID:Altered oxygen tension modulates cytokine-induced signal transduction in polymorphonuclear leukocytes: regulation of the GPLD pathway. 870 96

The gastroduodenal response to chronic Helicobacter pylori infection is characterized by the infiltration of plasma cells, lymphocytes, neutrophils and monocytes into the mucosa. Eradication studies have shown that this inflammatory response represents a specific reaction to the presence of H. pylori. As well as stimulating specific local T and B cell responses and a systemic antibody response, H. pylori infection also induces a local pro-inflammatory cytokine response. Interleukin-8 (IL-8), which is expressed and secreted by gastric epithelial cells, may be an important host mediator inducing neutrophil migration and activation. IL-8 mRNA and protein secretion in gastric epithelial cell lines can be up-regulated by the cytokines tumour necrosis factor-alpha and IL-1 and also by type I strains of H. pylori (expressing the vacuolating toxin and cytotoxin-associated protein, CagA). The gastric epithelium thus plays an active role in mucosal defence. Neutrophil activation and the production of reactive oxygen metabolites will be induced directly by bacterial factors and indirectly via host-derived cytokines, products of complement activation and bioactive lipids. Strain variation in the induction of both IL-8 from epithelial cells and the oxidative burst in neutrophils may be an important factor determining the extent of mucosal injury. There is now increasing evidence from both in vivo and in vitro studies that type I strains induce an enhanced inflammatory response and mucosal damage. An understanding of the bacterial mediators of mucosal inflammation is important in elucidating the role of chronic H. pylori infection in the pathogenesis of gastroduodenal disease.
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PMID:Immune and inflammatory responses to Helicobacter pylori infection. 872 76

Within the gastroduodenal mucosa Helicobacter pylori infection stimulates local production of a range of proinflammatory and immunoregulatory cytokines, neutrophil infiltration, specific T- and B-cell responses and the development of gastric lymphoid follicles. Following bacterial eradication this mucosal inflammatory response resolves. Infiltrating neutrophils are likely to be one of the major mediators of mucosal damage. Neutrophil activation, including reactive oxygen metabolite production and the release of myeloperoxidase, will be induced directly by bacterial factors and indirectly through products of complement activation, bioactive lipids and host-derived cytokines. Interleukin-8, and related peptides of the chemokine family secreted by gastric epithelial cells, are likely to be important host mediators inducing neutrophil migration to sites of infection. Epithelial IL-8 is upregulated by TNF-alpha and IL-1 and directly by H. pylori strains expressing the CagA phenotype. The extent of mucosal injury may reflect bacterial density, the variability of different strains of H. pylori to induce chemokine expression in epithelial cells and the oxidative burst in neutrophils. Recent evidence from in vivo and in vitro studies shows that CagA+ VacA+ strains of H. pylori are associated with enhanced inflammatory responses and mucosal damage. Defining the specific bacterial mediators of mucosal inflammation will be important in elucidating the role of H. pylori in the pathogenesis of gastroduodenal disease.
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PMID:Gastric mucosal inflammatory responses to Helicobacter pylori. 873 Feb 57

Human polymorphonuclear neutrophils (PMN) and cytokines play a critical role in host defences against invading microorganisms. In response to a variety of stimuli, PMN are a major source of reactive oxygen species (ROS) which are essential for bacterial killing and may induce oxidative stress in tissue environment. A precise regulation of the oxidase activity is therefore necessary. Cytokines such as TNF alpha, GM-CSF, IL-8, IL-6, IL-1 alpha and IL-1 beta produced during the immune and inflammatory responses to pathogens have been reported to interact with PMN activities. However, contradictory results have been reported on their direct and priming effects on the PMN release of ROS (oxidative burst). We have used a flow cytometry method to study the effects of these cytokines on the oxidative burst of PMN in whole blood, in order to avoid PMN activation related to isolation procedures. None of the cytokines tested directly activated the PMN oxidative burst, but they did have differential priming effects on the oxidative burst in response to N-formyl peptides. TNF, GM-CSF and IL-8 strongly primed a subpopulation of PMN to produce H2O2 in response to fMLP, while IL-1 alpha, IL-1 beta and IL-6 failed to do so. Furthermore, the addition of TNF, GM-CSF or IL-8 to whole blood increased the capacity of a subpopulation of PMN to bind N-formyl peptides, a phenomenon that could account for the strong H2O2 production in response to fMLP following priming by the cytokines. These results show that, among the various cytokines tested, TNF, GM-CSF and IL-8 strongly prime the PMN oxidative burst in response to bacterial peptides in whole blood and suggest that these cytokines may play a critical role in bacterial killing in vivo and also in the surrounding tissue injury secondary to pathological inflammatory reactions. In particular, TNF and IL-8 plasma levels as well as LPS-induced monocytic production of these cytokines ex vivo have been correlated with the production of ROS by stimulated PMN and with the lung injury score in patients with Adult Respiratory Distress Syndrom (ARDS). However, desensitization phenomena have also been described. In particular, in HIV infected patients we demonstrated a decrease of H2O2 production by PMN in whole blood after ex vivo priming by IL-8 and TNF followed by fMLP stimulation. This decrease increased with the progression of the disease and was inversely correlated with IL-8 plasma level. Different mechanisms could explain such desensitization phenomena at the receptor and post receptor level. In addition cytokines are involved in a complex network of regulation and anti inflammatory cytokines, such as IL-10, could act as a negative signal on the proinflammatory cytokines induced-priming of oxidative burst.
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PMID:[Modulation of the oxidative burst of human neutrophils by pro- and anti-inflammatory cytokines]. 873 98

To understand the pathophysiology of high-altitude pulmonary edema (HAPE), we examined the pathway of adaptation to high altitude in lifelong of Tibet. The Tibetan natives had higher exercise performance, but lower maximal oxygen uptake and lower blood lactate concentrations than did acclimatized Han newcomers. Clinical and basic studies done to determine the pathophysiologic characteristics of 47 patients with HAPE and of subjects susceptible to HAPE. The altitude of onset was 2,680 m to 3,190 m above sea level. Results of hemodynamic studies and the presence of protein-rich edema fluid indicated that HAPE is noncardiogenic and is a type of increased permeability edema. The levels of IL-1 beta, IL-6, IL-8, and TNF-alpha in bronchoalveolar lavage fluid from subjects with HAPE were high on admission. The subjects susceptible to HAPE had much greater increases in an index of pulmonary vascular resistance than did the controls, which resulted in much higher levels of pulmonary arterial pressure during both acute hypoxia and hypobaria. The subjects susceptible to HAPE also has blunted hypoxic ventilatory drives. We studied whether human leukocyte antigen DR-6 functions as a genetic predisposition to HAPE. The frequency of DR-6 was increased in the subjects susceptible to HAPE, which suggests that they have a constitutional abnormality in the pulmonary circulatory, and ventilatory responses to hypoxia and hypobaria, and that genetic factors may be involved in the development of HAPE.
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PMID:[High-altitude pulmonary edema in Japan]. 875 74

Many different cellular processes are altered by microenvironmental changes in the oxygen level, particularly hypoxia. In most cases, these hypoxic effects are mediated via alterations in cellular signal transduction pathways. Low oxygen states are generally viewed as deleterious; however, recent studies show that alterations in oxygen levels are physiologically important, influencing cells in a variety of ways. Low oxygen levels can stimulate cellular processes, such as the production of tumor necrosis factor, interleukin (IL)-1, IL-8, and nuclear factor kappa B. Kupffer cell-mediated alterations in cocultured hepatocyte function are altered by pre-exposure to hypoxic culture conditions, whereas superoxide production, intracellular pH, and adenosine triphosphate levels are decreased by hypoxia. Hypoxia followed by reoxygenation stimulates tyrosine kinase enzymes and increases intracellular calcium in a variety of cells. This review highlights recent findings concerning the manner and mechanisms by which low oxygen levels influence cell functions and cellular signaling systems. Detailed information is still lacking about the location and mechanism of most hypoxic-mediated alterations in cell signaling pathways. However, information about how factors altered by trauma and sepsis, such as Po2, acidosis, and endotoxin, effect cellular signaling pathways is rapidly emerging. Understanding the mechanism by which oxygen availability alters cell function will be important to the development of optimal therapies for post-traumatic shock and organ dysfunction.
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PMID:Hypoxic alterations in cellular signal transduction in shock and sepsis. 877 93

Ischemia is an interruption of oxygen and nutrient supply to a determined area of tissue for a period of time. Because of the heterogeneity of various tissues with regard to their microvascular flow reserve and oxidative capacity, as well as their markedly different metabolic needs, a single critical Po2 level below which ischemia occurs is unlikely. This is why there are variations of tolerance to hypoxia within and among organs. In general, when Pao2 reaches approximately 5 torr there is already evidence, in some organs, of altered cellular energetics. In addition, cessation of flow impairs the incoming transfer of nutrients such as glucose, and cells must depend on their own intracellular stores of carbon radicals, if available. Epidemiologic data suggest that there are deleterious effects of hypoxia on the immune system and that these effects result in increased susceptibility to infection. The histology of ischemic tissues demonstrates intravascular neutrophil (PMN) accumulation, vascular damage, and increased vascular permeability. Expression of PMN adhesion receptors is increased when oxygen is nearly completely removed from the medium. Expression of integrins on the cell surface is regulated by intracellular calcium; hypoxia causes a sustained and prolonged increase of intracellular calcium levels. Because both granule movement and functional expression of adhesion receptors on the cell surface are important in leukocyte motility, chemotaxis, and phagocytosis, these functions may be impaired by hypoxia. Exposure of a human macrophage cell line to nonlethal levels of hypoxia causes in vitro release of significant amounts of biologically active cytokines tumor necrosis factor (TNF) alpha, interleukin (IL)-1 and IL-8, as well as expression of intercellular adhesion molecule-1 and bound and soluble receptors for TNF alpha. Hypoxia markedly decreases T-lymphocyte IL-2 messenger RNA, a key cytokine responsible for B-cell proliferation and immunoglobulin secretion.
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PMID:Leukocyte responses to hypoxic/ischemic conditions. 877 94


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