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)

Results are presented that demonstrate a heightened responsiveness of human bronchial epithelial cells (HBECs) toward the complement-derived anaphylatoxin C5a when these cells are exposed to cigarette smoke. This C5a response is possible because we show at both the protein and mRNA levels that HBECs constitutively express receptors for C5a (C5aR, CD88). Control (untreated) HBECs responded to C5a (50 nM) by releasing the proinflammatory cytokine IL-8 at low but significant levels. However, exposure of HBECs to 5% cigarette smoke extract (CSE) for at least 15 min resulted in an increase in the ability of an anti-human C5aR Ab to bind to the cell surface. CSE-treated HBECs responded in a dose-dependent fashion to human recombinant C5a and to a conformationally biased decapeptide agonist of C5a (YSFKPMPLaR) by releasing IL-8. The levels of IL-8 released in response to C5a were significantly greater in CSE-treated HBECs than in control HBECs. Moreover, this C5a-mediated release of IL-8 from CSE-treated HBECs was significantly reduced in the presence of the anti-human C5aR Ab. These results indicate that HBECs constitutively express C5aRs and that exposure to environmental irritants such as cigarette smoke modulates the expression and responsiveness of these C5aRs toward the C5a-mediated release of IL-8.
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PMID:Expression of receptors for C5a anaphylatoxin (CD88) on human bronchial epithelial cells: enhancement of C5a-mediated release of IL-8 upon exposure to cigarette smoke. 959 Feb 58

The aim of the present work was to define an FSH receptor (FSHR) peptide that can induce antibodies that will inhibit the bioactivity of FSH. Therefore, the hFSHR sequence was aligned with that of all other known G-protein coupled receptors. An area with increased sequence homology was identified between the FSH-, LH-, TSH receptors, the C5a receptor and the IL8 receptor. The similarity consists of a richness in acidic (D and E) and hydrophobic (Y and F) residues. In hFSHR the sequence is EDNESSYSRGFDMTYTEFDYDLCNEVVD (amino acid 299-326). Research on both the C5a- and IL8-receptor has indicated that this part is responsible for hormone binding but not for signal transduction. Protamine. an antagonist for both the C5a- and IL8 receptor also inhibited the bioactivities of FSH and LH when tested in a bioassay. This suggests that in the hFSHR this region might also be involved in hormone binding. Specificity of this region towards the diverse ligands all binding to the C5a or to the IL8 receptor might be attributed to differences in the profile of alternating basic and hydrophobic residues. Therefore, the hypothesis was tested as to whether antisera raised against peptides of this FSHR-domain would inhibit FSH-bioactivity but not LH-bioactivity. Indeed antisera were found (anti-hFSHR 309-322) that inhibited the biological activity of FSH in a bioassay. These antisera proved to be specific since they did not inhibit the bioactivity of LH. These data suggest that the core sequence (hFSHR 309-322) of the aligned domain of the hFSHR, in analogy to the IL8- and C5a receptors, is involved in hormone binding and ligand specificity. This domain therefore forms a valuable tool in FSH- and FSHR research for scientific and medical purposes.
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PMID:In vitro inhibition of the bioactivity of follicle-stimulating hormone by antisera against a peptide representing part of the FSH-receptor. 973 Feb 88

Engineering proteins to contain a histidine (His)-tag has proved to be very useful for the purification and analyses of these molecules. In the present study, we demonstrate that the binding of His-tagged ligands to their receptors may be visualised by flow cytometry making use of a selected monoclonal antibody (mAb) against the His-tag. Employing this method, a recombinant C3a (rC3a) anaphylatoxin with a His-tag at its N-terminus could be shown to bind to C3a receptor (C3aR)-expressing RBL-2H3 transfectants with a half-maximal effective concentration (EC50) of about 3 nM which is well within the range of published affinity constants. Binding of a recombinant interleukin-8 (rIL-8) molecule with a C-terminal His-tag to RBL-2H3 cells which stably express the IL-8 receptors CXCR1 or CXCR2 could also be demonstrated using the tag-specific mAb. Furthermore, aminoterminally tagged C5a molecules of rat or human origin could be shown to bind to the human C5a receptor (C5aR). However, the fluorescence signal of the binding of rat rC5a to the human C5aR was distinctly higher over a wide range of ligand concentrations than the signal of human rC5a binding although both ligands were equally potent in the induction of chemotaxis in C5aR-expressing cells. Thus, the tag-specific mAb was able to interfere with the binding of human but not rat rC5a to the human C5aR. This observation is in agreement with the hypothesis of a two binding site model for the interaction of human C5a with its receptor whereas a different binding mode may apply for rat C5a. Our data demonstrate that the selected His-tag specific mAb may be a valuable tool for the visualisation of the binding of recombinant ligands to their receptors and may also provide useful information on the specific binding properties of the ligands.
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PMID:Specific detection by flow cytometry of histidine-tagged ligands bound to their receptors using a tag-specific monoclonal antibody. 1041 Sep 79

Interleukin (IL)-8 production by human polymorphonuclear leukocytes (PMNL) to Cryptococcus neoformans is related to complement activation. Generation of the bioactive fragments C3a and C5a is responsible for IL-8 release. IL-8 production was analyzed in response to C. neoformans by PMNL from persons with early- and late-stage (>400 and <200 CD4 cells/mm3, respectively) human immunodeficiency virus (HIV) infection who were at high risk for cryptococcosis. IL-8 release by PMNL from persons with early-stage infection and from healthy donors was similar; however, PMNL from persons with late-stage HIV infection had significantly impaired IL-8 production, which correlated with reduced IL-8 response to C3a and C5a proteins and decreased CD88 expression. Addition of murine monoclonal antibody (MAb) 18B7 promoted phagocytosis and restored IL-8 release consistent with integrity of FcgammaRIII. These results provide evidence for a selective defect in CD88 expression on PMNL from persons with late-stage HIV infection. However, Fcgamma receptor expression in PMNL appears to be intact and allows MAb to glucuronoxylomannan to positively influence PMNL function.
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PMID:Neutrophils from patients with advanced human immunodeficiency virus infection have impaired complement receptor function and preserved Fcgamma receptor function. 1051 14

At the site of acute inflammation, leukocytes are confronted with multiple mediators which are expected to modulate each other with respect to cell responses to the individual ligand. In the present study, we compared the effects of the classical chemoattractants FMLP, PAF and LTB4, of the chemokine IL-8 and of TNFalpha, GM-CSF, IFN-gamma and IL-1beta on C5a-induced chemotaxis, degranulation, oxidative burst and expression of adhesion molecules of human neutrophils in vitro. Upon preincubation, TNFalpha as well as GM-CSF dose-dependently inhibited C5a-mediated chemotaxis, but augmented the release of elastase as well as respiratory burst activity. The effects of the two cytokines were accompanied by a downregulation of C5a receptors as determined by Scatchard analysis using (125)I-labeled C5a. Compared on a molar basis, TNFalpha was more effective than GM-CSF. C5a-induced expression of beta(2)-integrins was only moderately influenced by TNFalpha and GM-CSF. C5a itself diminished chemotaxis as well as degranulation and oxidative burst in response to a second dose of the same ligand (homologous desensitization), whereas heterologous desensitization by FMLP and IL-8 was restricted to C5a-induced degranulation or not observed (PAF, LTB4]. The cytokine effects are likely to be a consequence of altered C5a receptor expression as well as of postreceptor events. In concert with C5a, certain cytokines may shift neutrophil effector functions from migration to exocytosis, an essential step within the sequence of events in a coordinated inflammatory response.
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PMID:Modulation of C5a-mediated effector functions of human polymorphonuclear leukocytes by tumor necrosis factor alpha and granulocyte macrophage colony-stimulating factor. 1057 75

At the site of acute inflammation, leukocytes are confronted with multiple mediators which are expected to modulate each other with respect to cell responses to the individual ligand. Previous contact of neutrophils with pro-inflammatory cytokines, such as TNF-alpha or GM-CSF, or with the vitamin D binding protein (Gc-globulin) leads to the alteration of either multiple or rather distinct C5a-mediated neutrophil functions. Gc-globulin, the transport protein for 25-(OH)-D3, serves selectively as a cochemotactic factor for C5a/Ca(des)Arg. In contrast, TNF-alpha and GM-CSF, previously shown to modulate FMLP-induced neutrophil responses, are able to reduce C5a-mediated neutrophil chemotaxis, but augment their degranulation and respiratory burst activity. Cytokine priming was shown to be accompanied by a down-regulation of C5a receptors (CD88) whereas vitamin D binding protein had no impact on the level of neutrophil C5a receptors. C5a itself diminishes chemotaxis as well as degranulation and oxidative burst in response to a second dose of the same ligand (homologous desensitization). A similar effect, termed heterologous desensitization, occurs, if cell responses to a given mediator (e.g. to C5a) are reduced or even abolished upon the activation of another receptor of the same G-protein coupled chemoattractant receptor subfamily (e.g. receptors for FMLP or IL-8). In concert with C5a, certain molecules may either augment chemotaxis or shift neutrophil effector functions from migration to exocytosis, an essential step within the sequence of events in a coordinated inflammatory response.
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PMID:Neutrophil priming by cytokines and vitamin D binding protein (Gc-globulin): impact on C5a-mediated chemotaxis, degranulation and respiratory burst. 1069 43

Complement plays an essential role in inflammation and tissue damage. However, it is largely unknown to what extent the system acts as a primary inducer of secondary mediator systems in the inflammatory network of human whole blood. Here we describe a novel in vitro model using the thrombin-specific hirudin analog lepirudin as anticoagulant, which, in contrast to heparin, did not interfere with complement activation. The model was used to study the role of complement in Escherichia coli-induced inflammatory responses. Granulocyte and monocyte oxidative burst was complement dependent as it was reduced by 85% and 70%, respectively, by the C3 [corrected] binding peptide compstatin. A similar reduction was found by inhibition of C5, C5a, and C5a receptor (C5aR). Furthermore, anti-CR3 antibodies were as efficient as the C5aR antagonist in reducing granulocyte oxidative burst, whereas blocking CD14 or C3aR had no effect. Up-regulation of granulocyte CR3 was virtually abolished by a C5aR antagonist. Opsonization and phagocytosis was completely inhibited by blocking of C5aR or CR3, whereas blocking of the FcgammaRs (CD16, CD32, CD64) had no effect. In contrast to oxidative burst and phagocytosis, cytokine secretion was largely complement independent. Thus, anti-CD14 abolished tumor necrosis factor-alpha, interleukin-6 (IL-6), and IL-10 secretion, whereas IL-8 was equally inhibited by anti-CD14 and compstatin. In conclusion, the present model is particularly useful for studying complement as part of the inflammatory network. The results emphasize a crucial role for C5a-C5aR interaction in E coli-induced up-regulation of CR3 and the subsequent oxidative burst and phagocytosis. Complement inhibition may have therapeutic implications in oxidative burst-induced tissue damage.
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PMID:Essential role of the C5a receptor in E coli-induced oxidative burst and phagocytosis revealed by a novel lepirudin-based human whole blood model of inflammation. 1217 11

C3a and C5a anaphylatoxins are cytokine-like polypeptides generated during complement (C) system activation and released at the inflammatory site. They exert several biological activities through binding to the G-protein-coupled receptors C3aR and C5aR, respectively. Cloning and Northern blot experiments have indicated that both receptors are expressed by myeloid as well as nonmyeloid cells (e.g., endothelial and epithelial cells). To better understand the roles of C anaphylatoxins during inflammation, we investigated their effects on the expression of cytokine and chemokine genes by cultured human umbilical cord endothelial cells (HUVEC). HUVEC constitutively expressed both anaphylatoxin receptors, and addition of physiological concentrations of C3a or C5a (nM range) caused a strong up-regulation of IL-8, IL-1beta, and RANTES mRNA in a time- and dose-dependent manner. Conversely, a decrease in IL-6 mRNA was observed, but only with C5a stimulation. These variations in mRNA levels were inhibited by pretreatment with anti-C5aR and anti-C3aR antibodies as well as pertussis toxin, indicating that G-proteins are involved in anaphylatoxin-activated signal transduction pathways. Finally, we showed that C3a and C5a both strongly activate downstream MAP kinase signaling pathways (p44 and p42 Erk kinases).
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PMID:Regulation by complement C3a and C5a anaphylatoxins of cytokine production in human umbilical vein endothelial cells. 1277 83

Real-time reverse transcriptase polymerase chain reaction (RT rtPCR) was used to quantify the pattern of inflammatory mediator mRNA expression in circulating leukocytes from adult patients diagnosed with severe sepsis. We analysed 29 blood samples from 26 severely septic patients with different septic sources and eight samples from eight healthy adult volunteers. RT rtPCR was used to quantify mRNA expression of 21 different inflammatory mediators in peripheral leukocytes. The median variability in gene expression in the sepsis patients was 10.5 times greater than the variability of the healthy comparison group. We found a significant change in the regulation for the following genes: C5aR (20-fold, P < 0.001), IL-8 (29-fold, P < 0.001), MMP9 (72-fold, P < 0.001), HSP70 (2.4-fold, P = 0.02), and RIP2 (1.8-fold, P < 0.04) were up-regulated. Conversely the median expression of IFNgamma, and IL-6 were zero (P < 0.001), and mtHSP (0.4-fold, P = 0.02) was significantly down-regulated. Using linear discriminant analysis, IFNgamma, IL-12, and TLR4 were correlated to a negative outcome. Different septic sources (peritonitis, burn, pneumonia and musculo-skeletal infections) resulted in significantly different mRNA patterns. The RT rtPCR is a useful tool to monitor the immune response in septic patients. We found a very high variability in inflammatory mediator expression among septic patients compared to healthy volunteers. This suggests that any future immune-modulatory therapy may need to be individualized to the patient's requirements as monitored by RT rtPCR. Different sources of sepsis may result in markedly different activation patterns.
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PMID:The use of real time rtPCR to quantify inflammatory mediator expression in leukocytes from patients with severe sepsis. 1564 82

The aim of this longitudinal observational study was to investigate and describe the spectrum of messenger ribonucleic acid (mRNA) expression of multiple inflammatory markers in circulating leukocytes after major orthopaedic surgery. We studied ten elective arthroplasty patients perioperatively on the orthopaedic ward, and eight healthy volunteers for a comparison group. Venous blood specimens were collected preoperatively, and 6, and 24 hours postoperatively, together with 6- and 24-hour postoperative wound drain specimens. The mRNA of 21 different inflammatory mediators was measured by real-time reverse transcriptase Polymerase Chain Reaction. Comparisons were made with the venous blood of eight healthy comparison subjects. There were significant differences (P<0.01) between preoperative specimens and normal comparisons (i.e. higher MPO, PDGF, TREM and IRAKM; lower mtHSP) reflecting the effects of chronic inflammation associated with osteoarthritis. There were significant increases (P<0.01) in expression of IL-8, MPO, IL-1beta, TREM, MMP9, and C5aR in circulating blood at 24 hours postoperatively, but not at six hours. There was no significant decrease in expression of any inflammatory mediator. There was no statistical difference in inflammatory mediator expression between drain specimens and venous specimens taken at the same time. We conclude that, in uncomplicated orthopaedic surgical patients, there was up-regulation of some cytokine mRNAs at both the local and systemic levels during the first day after surgery. We observed no evidence of immune compartmentalization, and found no evidence for innate immune paresis within the first day after surgery.
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PMID:Messenger RNA expression of multiple immune mediators in leukocytes from elective orthopaedic surgical patients. 1595 15


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