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)

We investigated cellular responses in a rabbit to i.v. administration of five established chemotactic factors (leukotriene B4 (LTB4), platelet-activating factor (PAF), C5a, N-Formyl-Met-Leu-Phe (F-MLF), and IL-8), and each exerted a characteristic effect on circulating white blood cell levels. All five factors induced a rapid and transient leukopenia. The blood was nearly devoid of circulating neutrophils 5 min after administration of each chemotactic factor. Other leukocytes were also variably depleted during the leukopenic phase, including eosinophils, basophils, monocytes, and lymphocytes. The lymphocyte numbers remained significantly depressed (approximately 30%) for as long as 3 h after administration of PAF or f-MLF. Each chemotactic factor produced a marked neutrophilia (i.e., 250-400% of baseline levels) after the initial leukopenia. Eosinophil numbers were elevated along with the neutrophil response in the C5a- and LTB4-treated animals. Basophil levels were significantly elevated only in LTB4-treated animals. The cellular response to PAF, f-MLF, and IL-8 appeared to be specific for the neutrophils. The kinetic profiles of the neutrophilia induced by PAF (10 micrograms/kg) or f-MLF (2.5 micrograms/kg) were similar, with maximal responses occurring 3 to 4 h after administration. In contrast, LTB4 (10 micrograms/kg), IL-8 (2.5 micrograms/kg), and C5a (5 micrograms/kg) induced a more rapid neutrophilia, with peak responses occurring 1 to 1.5 h after injection, and remaining elevated for 3 to 4 h. In all animals the neutrophilia was accompanied by a relative increase in the number of nonsegmented neutrophils (bands), suggesting that a major component of leukocytosis is caused by the release of bone marrow reserves. Phenidone (10 mg/kg), a dual cyclooxygenase/5-lipoxygenase inhibitor, affected neither the neutropenia nor the neutrophilia induced by C5a, f-MLF, or PAF. The protein synthesis inhibitor actinomycin D also failed to suppress neutrophil responses induced by either C5a or PAF. These results suggest that leukocytosis is a common response induced by all neutrophil chemotactic factors. Leukocytosis appears to be a direct result of the dynamic adaptive response of neutrophils to chemotactic factor stimulation without involvement of a secondary mediator system.
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PMID:Neutrophil chemotactic factors promote leukocytosis. A common mechanism for cellular recruitment from bone marrow. 131 Jul 8

Whatever initiates inflammation, the final message mediating cellular invasion is chemical. This consideration allows rational development of anti-inflammatory treatments. Two main classes of chemotactic mediator are recognised. Water-soluble peptides, e.g. cytokines derived from macrophages and other cells, play an important integrating part in the early recruitment of neutrophils and mononuclear cells, and in the amplification of immune responses. Lipid-soluble mediators, of which leukotriene B4 is the most highly chemotactic for neutrophils, are important in secondary amplification. In inflammatory bowel disease, we have shown evidence of increased synthesis of cytokines interleukin 1, 6 and 8. These are associated with activation of circulating monocytes in active Crohn's disease, of lamina propria macrophages in relapse of both ulcerative colitis and Crohn's disease, and development of adhesion molecules on vascular endothelium. Our studies show that interleukin 6 is selectively increased in Crohn's disease, whilst preliminary findings suggest that enhanced synthesis of interleukin 8 is particularly characteristic of ulcerative colitis. Patterns of cytokine synthesis may, therefore, be of diagnostic value. They also offer the potential for therapeutic strategies since cytokine antagonists are becoming available. We have also demonstrated increased synthesis of leukotrienes in active inflammatory bowel disease. Since leukotriene B4 is quantitatively the main chemotactic signal in the mucosa in inflammatory bowel disease during relapse, we investigated the therapeutic effect of suppressing leukotriene B4 synthesis by treating patients with fish oil (as Hi-EPA), giving 4.5 g daily of eicosapentaenoic acid. This competes for the 5-lipoxygenase enzymes, inhibiting leukotriene B4 and promoting synthesis of the less chemotactic product, LTB5.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Therapeutic interventions in gastrointestinal disease based on an understanding of inflammatory mediators. 135 43

Interleukin-8 (IL-8), is a potent activator of polymorphonuclear leukocyte (PMN) functions including chemotaxis, superoxide anion production, and enzyme release and it is also chemotactic for lymphocytes. Additionally, it has recently been shown that IL-8 stimulates the formation of 5-lipoxygenase (LO) products of arachidonic acid (AA) by human PMNs. The purpose of the present study was to determine whether IL-8 also might affect the formation of 15-LO products from AA. Purified PMNs in phosphate buffered saline were preincubated with and without exogenous AA (10(-5)-10(-4) M) for 10 min. Then IL-8 was added in biologically relevant concentrations ranging from 0.1 to 100 ng/ml and incubation was carried out for 5 min at 37 degrees C. Lipids were then extracted from supernatants, and eicosanoids were determined by quantitative RP-HPLC. Compared with unstimulated cells, IL-8 resulted in a dose dependent increase in both LTB4 and 15-HETE (up to 125% and 40% at 100 ng/ml, respectively). This increase in eicosanoid formation required the presence of exogenous AA. These results indicate that IL-8 is both a potent stimulator of 5-LO activity and of 15-LO activity. LTB4 can induce both inflammation and contribute to hyperproliferation in the skin. 15-HETE in contrast has the ability to inhibit the effects induced by LTB4. Because IL-8 is able to stimulate both LTB4 and 15-HETE formation, the effect of IL-8 as a putative regulator of inflammatory processes may be dependent on the relative stimulation of 5-LO and 15-LO.
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PMID:Interleukin-8 stimulates the formation of 15-hydroxy-eicosatetraenoic acid by human neutrophils in vitro. 152 97

LPS and mitogen-stimulated mononuclear cells secrete a cytokine, which is able to activate the PMNL-arachidonate-5-lipoxygenase. This cytokine has been proven to be identical with the recently characterized novel neutrophil-activating peptide NAP/IL-8. NAP/IL-8 is able to activate human PMNL for release of LTB4, omega-oxidized LTB4, and 5-HETE in the presence of exogenous AA. Half-maximal concentration of NAP/IL-8 for release of LTB4 has been found to be near 4 x 10(-8) mol/liter. Time course studies revealed rapid activation of PMNL, with maximal release of LTB4 within the first 10 min with a decline up to 40 min. High amounts of omega-oxidized LTB4 were detected up to that time. Significant amounts of AA-5-LO-products can be detected only when PMNL were stimulated with NAP/IL-8 in the presence of exogenous AA. The concentration of AA necessary for half-maximal LTB4 release has been found to be 3 x 10(-6) mol/liter. In the presence of 8 x 10(-9) mol/liter [3H]AA, NAP/IL-8 (10(-9) to 10(-7) mol/liter) did not induce the production of LTB4, omega-oxidized LTB4, or 5-HETE. In addition, PMNL prelabeled with [3H]AA did not release either [3H]AA or 5-lipoxygenase metabolites when stimulated with NAP/IL-8 (10(-9) to 10(-7) mol/liter), indicating that NAP/IL-8 apparently does not activate cellular phospholipases/diacylglycerol-lipases. Apart from FMLP, C5a, and PAF NAP/IL-8 is the fourth clearly characterized neutrophil chemotaxin able to activate the PMNL-5-lipoxygenase. The detection of large amounts of NAP/IL-8, arachidonic acid, as well as LTB4-like material, in lesional material of patients with psoriasis points towards a possibly important role of NAP/IL-8 in amplifying inflammatory processes by induction of LTB4-production.
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PMID:The monocyte-derived neutrophil activating peptide (NAP/interleukin 8) stimulates human neutrophil arachidonate-5-lipoxygenase, but not the release of cellular arachidonate. 254 66

Previously, we have shown that Escherichia coli alpha-hemolysin represents a potent stimulus for inflammatory mediator release (O2- release, beta-glucuronidase release, and leukotriene generation) from human polymorphonuclear granulocytes (PMN) as well as for histamine release from a human lymphocyte-monocyte-basophil cell suspension (LMB). In contrast, the E. coli alpha-hemolysin leads to a downregulation of cytokine release (interleukin 6 [IL-6], tumor necrosis factor alpha, and IL-1 beta) from human LMB. This study was undertaken (i) to analyze the priming efficacy of growth factors (granulocyte-macrophage colony-stimulating factor [GM-CSF] and granulocyte CSF [G-CSF]) on inflammatory mediator release from human PMN and LMB challenged with hemolysin-producing E. coli bacteria as well as with cell-free E. coli alpha-hemolysin and (ii) to identify major components involved in GM-CSF and G-CSF priming. GM-CSF pretreatment led to an increased chemiluminescence response from human PMN by up to 100%, leukotriene B4 generation was enhanced up to fivefold, and histamine release from human LMB increased from 45% +/- 15% to 75% +/- 5% (mean +/- standard distribution) of the total histamine content. G-CSF priming induced an increase in the chemiluminescence response by up to 50% +/- 5% from human PMN and an increase in histamine release from human LMB by 20% +/- 5%. The growth factors, GM-CSF and G-CSF, modulated neither beta-glucuronidase release from human PMN nor IL-8 release from human PMN and LMB challenged with the E. coli alpha-hemolysin. GM-CSF and G-CSF pretreatment increased the fluoride (NaF)-induced chemiluminescence response by up to 10-fold; the serine/threonine phosphatase inhibitor okadaic acid inhibited GM-CSF- and G-CSF-induced priming. NaF-induced histamine release was enhanced up to 60 and 30% by GM-CSF and G-CSF priming, respectively. GM-CSF and G-CSF pretreatment did not modulate phorbol 12-myristate 13-acetate-induced chemiluminescence response or histamine release. GM-CSF by itself induced an increase in 5-lipoxygenase-specific mRNA expression within 5 min. Our results indicate that (i) GM-CSF and G-CSF interact with inflammatory cells via distinct cellular signalling, (ii) the signal transduction pathway is dependent on the cellular mediator, and (iii) the use of growth factors may be a potent tool to influence the clinical outcome in infectious diseases.
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PMID:Effect of growth factors on Escherichia coli alpha-hemolysin-induced mediator release from human inflammatory cells: involvement of the signal transduction pathway. 751 12

The promyelocytic HL 60 cell line can be used as an in vitro model system to study hematopoetic cell differentiation and inflammatory events. We studied the signal transduction pathway of induced interleukin (IL)-8 expression and compared it with those of tumor necrosis factor alpha (TNF-alpha), IL-1 alpha, and IL-1 beta. The differentiation of HL 60 cells to macrophage-like cells by PMA resulted in a rapid and marked induction of these inflammatory cytokines. The up-regulation occurred in the absence of ongoing protein synthesis, but cycloheximide-sensitive gene products modulated their induction kinetics. Staurosporine, a potent inhibitor of protein kinases, strongly inhibited their gene expression. Phosphorylation may not act directly on latent transcription factors, since bromophenacyl bromide, an inhibitor for the release of arachidonic acid from phorbol-12 myristate 13-acetate (PMA)-stimulated HL 60 cells, markedly depressed the induced mRNAs for IL-8, TNF-alpha, and IL-1 alpha and -beta. Similarly, 5,8,11,14 eicosatetraynoic acid (ETYA), another inhibitor of the arachidonic acid pathway, blocked the induction of transcripts for TNF-alpha, and both IL-1 genes in phorbol ester-stimulated HL 60 cells. In contrast, ETYA increased the induced IL-8 RNA levels and stimulated the release for IL-8. Also, ketoconazole, an inhibitor of 5-lipoxygenase and indomethacin, an inhibitor of cyclooxygenases did not block the induction of IL-8 mRNA. However, the release of IL-8 protein was regulated by indomethacin and ketoconazole. Our results indicate that arachidonic acid metabolites are mediators in the signal transduction pathway of IL-8 expression and that the involved second messengers are different from those which are important for the induction of TNF-alpha and IL-1 beta expression.
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PMID:Inhibition of the arachidonic acid pathway prevents induction of IL-8 mRNA by phorbol ester and changes the release of IL-8 from HL 60 cells: differential inhibition of induced expression of IL-8, TNF-alpha, IL-1 alpha, and IL-1 beta. 755 7

Stimulation of heparinized blood with 1 microM formyl-methionyl-leucyl-phenylalanine (FMLP) resulted in the formation of < 30 pmol/ml plasma of 5-lipoxygenase (5-LO) products. The preincubation of blood with 1 microgram/ml of lipopolysaccharide (LPS) (Escherichia coli 0111-B4) for 30 min before stimulation with FMLP resulted in the accumulation of 250-300 pmol of 5-LO products per ml plasma. The major products detected were leukotriene B4 and (5S)-hydroxy-6,8,11,14-eicosatetraenoic acid which were produced in equivalent amounts. The priming activity was detectable with as little as 1-10 ng LPS per ml blood and was optimal using 1-10 micrograms LPS/ml blood. The priming for 5-LO product synthesis was optimal after 20-30 min of preincubation with LPS and declined at preincubation times > 30 min. The priming effect of LPS was also observed using the complement fragment C5a or interleukin 8 as agonists. Polymorphonuclear leukocytes (PMN) and peripheral blood mononuclear cells accounted for 80 and 20% of the synthesis of 5-LO products, respectively. The ability of LPS to prime isolated PMN was dependent on the presence of plasma and was inhibited by the anti-CD14 antibody IOM2, indicating a CD14-dependent priming mechanism. The priming of whole blood with tumor necrosis factor alpha (TNF-alpha) and LPS was additive and the presence of mononuclear cells did not enhance the ability of LPS to prime PMN, indicating that the priming activity of LPS is independent of LPS-induced TNF-alpha synthesis. The mechanism by which LPS enhance 5-LO product synthesis in PMN was investigated. Treatment of PMN with LPS strongly enhanced the release of arachidonic acid after stimulation with FMLP. The release of arachidonic acid was optimal 2-3 min after stimulation with FMLP, attaining levels 5-15-fold greater than those observed in unprimed cells stimulated with FMLP. These results demonstrate that LPS dramatically increases the ability of blood to generate 5-LO products, and support the putative role of leukotrienes in pathological states involving LPS.
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PMID:Lipopolysaccharides prime whole human blood and isolated neutrophils for the increased synthesis of 5-lipoxygenase products by enhancing arachidonic acid availability: involvement of the CD14 antigen. 769 Aug 33

We found that intrinsic neutrophil 5-lipoxygenase activity was necessary for human neutrophil adherence and chemotaxis in vitro and human neutrophil-mediated acute edematous injury in isolated perfused rat lungs given interleukin 8 intratracheally. Treatment with either Zileuton (a specific reversible competitive inhibitor of 5-lipoxygenase) or MK886 (a specific irreversible inhibitor of the 5-lipoxygenase activator protein) prevented stimulated neutrophil adherence and chemotaxis (but not superoxide anion production) in vitro. Zileuton- or MK886-inhibited neutrophil chemotaxis was not restored by adding leukotriene B4 in vitro. Perfusion with neutrophils and either Zileuton or MK886, or with MK886-pretreated neutrophils (without adding MK886 to the perfusate), also prevented lung injury (reflected by lung weight gain and lung Ficoll retention) and perfusate leukotriene B4 increases in isolated rat lungs given interleukin 8 intratracheally. Again, adding leukotriene B4 to the perfusate did not damage interleukin 8-treated isolated lungs perfused with Zileuton-inhibited neutrophils. We conclude that intrinsic 5-lipoxygenase activity is required for neutrophil adherence and chemotaxis and neutrophil-mediated lung injury.
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PMID:Intrinsic 5-lipoxygenase activity is required for neutrophil responsivity. 805 73

Recent evidence suggests that phospholipase A2 (PLA2)-derived lipid mediators may regulate a number of neutrophil responses including degranulation and adhesion. In view of the potential role of PLA2 in stimulus-secretion coupling, we examined the relationship between PLA2 activation and the surface expression of CD11b/CD18 (MAC-1) in human polymorphonuclear leukocytes (hPMNL), including the functional consequences of PLA2 inactivation on MAC-1-dependent adhesion. The selective inhibition of PLA2 by the marine natural products manoalide (MLD) and scalaradial (SLD) blocks [3H]arachidonic acid (AA) release in calcium ionophore A23187-stimulated neutrophils, and also inhibits secretion of specific and azurophilic granule constituents. Additional studies demonstrate that MLD, SLD, and other less potent PLA2 inhibitors such as 4-bromophenacylbromide and nordihydroguiaretic acid inhibit the surface expression of MAC-1 (IC50: MLD, 0.33 microM; SLD, 0.23 microM; 4-bromophenacylbromide, 2.8 microM; NDGA, 3.5 microM) at concentrations similar to those at which they inhibit [3H]AA release. Inhibitors of cyclooxygenase, 5-lipoxygenase, protein kinase C, or calcium channel antagonists have no effect on MAC-1 expression. PLA2 inactivation also prevents MAC-1 up-regulation in hPMNL stimulated with FMLP, IL-8, TNF-alpha, PMA, or platelet activating factor. In FMLP-stimulated hPMNL, under conditions in which no secondary granule constituents are secreted, MAC-1 and alkaline phosphatase up-regulation from intracellular granules is inhibited by MLD and SLD. Functional assays also demonstrate that MLD and SLD block MAC-1-dependent adhesion of activated neutrophils to keyhole limpet hemocyanin at concentrations that block the surface expression of MAC-1. [3H]AA release and MAC-1 expression in MLD and SLD-treated hPMNL could be recovered in the presence of 1 mM hydroxylamine in a time-dependent fashion, consistent with reported data that MLD and SLD inactivate PLA2 through Schiff base formation. In summary, these data emphasize the role of PLA2 as a key regulator of MAC-1 expression in models of neutrophil adhesion.
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PMID:Regulation of CD11b/CD18 expression in human neutrophils by phospholipase A2. 822 53

In recent years, there has been a growing body of evidence suggesting that IL-8 and granulocyte-macrophage CSF (GM-CSF) play an important role in inflammatory processes. We show that after GM-CSF treatment, the exposure of human neutrophils to IL-8 results in the synthesis of leukotriene (LT)B4 and platelet-activating factor. In GM-CSF-treated cells, IL-8 induced a concentration-dependent synthesis of both lipid mediators, with a threshold at 10 to 30 nM, suggesting that IL-8 could stimulate phospholipase A2 activity, an enzyme essential for both syntheses. Accordingly, IL-8 induced a substantial release of 3H-arachidonic acid in GM-CSF-treated PMN. It was also found that IL-8 activates the neutrophil 5-lipoxygenase (5-LO), the other key enzyme in LT biosynthesis. IL-8 induced 5-LO activation in a time- and concentration-dependent manner, with a threshold at 1 nM, and prior treatment of neutrophils with GM-CSF enhanced this effect of IL-8 over the 1 to 300 nM range. Neutrophil-activating peptide-2 and the melanoma growth-stimulatory activity, two peptides that are closely related to IL-8, also had the ability to activate the 5-LO and stimulate LT synthesis, albeit less potently than IL-8. Finally, pertussis toxin and the 5-LO translocation inhibitor, MK-886, both blocked the IL-8-elicited 5-LO activation. Taken together, our results raise the possibility that the combined presence of IL-8 and of GM-CSF at inflammatory foci could result in the synthesis of platelet-activating factor and LTB4 by neutrophils, thereby contributing to the amplification of the inflammatory response.
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PMID:Induction by chemokines of lipid mediator synthesis in granulocyte-macrophage colony-stimulating factor-treated human neutrophils. 824 74


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