Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The CXC chemokine, IL-8, is a potent chemoattractant of neutrophils and binds to two distinct receptors, termed IL-8R1 and IL-8R2. These receptors share high affinity for IL-8, however, only IL-8R1 is specific for IL-8 whereas IL-8R2 binds other related chemokines, including GRO alpha with high affinity. Stable Jurkat transfectants were generated expressing either functional IL-8R1 or IL-8R2 (J-IL8R1 and J-IL8R2). Both J-IL8R1 and J-IL8R2 exhibited high affinity IL-8 binding (Kd 3-5 nM) with respective receptor densities of 23,000 +/- 3,000 and 18,500 +/- 1,500. Pre-treatment of both transfectants with 1.0 micrograms/ml B. pertussis toxin (PTx) resulted in inhibition of IL-8 mediated intracellular Ca2+ mobilisation and chemotaxis, without altering the receptor's affinity for its ligand. This indicates that both receptors couple to a PTx-sensitive G-protein. Further studies showed that IL-8R1 and IL-8R2 could mediate time-dependent phosphorylation of p42/p44 MAP-kinase. In both transfectants, phosphorylation was maximal at 1-2 min after IL-8 stimulation and could be inhibited by PTx. Stimulation of J-IL8R1 and J-IL8R2 with GRO alpha revealed that this chemokine was a more potent activator of MAP-kinase in J-IL8R2, an observation reflected in the high affinity binding of GRO alpha to IL-8R2. These studies indicate that chemokines are capable of activating protein kinases and with regards to PTx-sensitivity and MAP-kinase stimulation, no significant differences between IL-8R1 and IL-8R2 post-receptor signalling occur during cell activation by IL-8.
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PMID:A comparison of post-receptor signal transduction events in Jurkat cells transfected with either IL-8R1 or IL-8R2. Chemokine mediated activation of p42/p44 MAP-kinase (ERK-2). 775 May 73

Using recombinantly expressed proteins and synthetic peptides, we examined the structural/functional features of the platelet chemokines, neutrophil-activating peptide-2 (NAP-2) and platelet factor 4 (PF4); that were important in their activation of neutrophils. Previous studies with the chemokine interleukin-8 (IL-8) had shown that the N-terminal region preceding the first cysteine residue was critical in defining neutrophil-activating properties. We examined whether NAP-2 and PF4 had similar structural requirements. In the Ale-glu-leu-arg (AELR) N-terminus of NAP-2, substitution of E or R abolished Ca2+ mobilization and elastase secretion. Unlike the parent molecule PF4, AELR/PF4, the hybrid formed by replacing the N-terminal sequence of PF4 before the first cysteine residue with the homologous sequence of NAP-2, stimulated Ca2+ mobilization and elastase secretion. Furthermore, the effect of amino acid substitutions in the ELR motif differed from those seen with NAP-2 in that conserved substitutions of E or R in NAP-2 abolished activity, but only reduced neutrophil activation in the hybrid. These studies show that just as with IL-8, the N-termini of NAP-2 and PF4 are critical for high-level neutrophil-activating function. Desensitization studies provided information on receptor binding. NAP-2, which binds almost exclusively to the type 2 IL-8 receptor (IL-8R), did not desensitize neutrophils to activation by IL-8 because IL-8 could bind to and activate via both type 1 and 2 IL-8R. AELR/PF4 appears to bind to both types of receptors because it desensitized neutrophils to NAP-2 activation; but was not desensitized by NAP-2, and because it desensitized to and was desensitized by IL-8. Thus, although NAP-2 and AELR/PF4 share approximately 60% amino acid homology, they have different receptor affinities. Studies were performed to define the role of the C-termini of these platelet chemokines in receptor binding. Heparin and a monoclonal antibody specific for the heparin-binding domain of PF4 both inhibited Ca2+ mobilization and elastase release, further suggesting that the C-terminus of these chemokines is important in receptor binding. Synthetic NAP-2(51-70) failed to mobilize Ca2+, whereas PF4(47-70) and PF4(58-70) induced Ca2+ mobilization and secretion of elastase at high concentrations. Pertussis toxin inhibited neutrophil activation by 40% to 50%, establishing a role for G-protein-coupled receptors such as the IL-8Rs in activation by the PF4 C-terminal peptides.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Structural requirements of platelet chemokines for neutrophil activation. 791 50

The class II IL-8 receptor (IL-8R) binds both melanoma growth stimulatory activity (MGSA) and IL-8 with high affinity. Reverse transcriptase polymerase chain reaction demonstrates that the class II IL-8R mRNA, which has previously been detected only in cells of hematopoietic lineage, is also expressed in non-hematopoietic cell types shown to respond to MGSA or IL-8. To study the signaling mechanism by MGSA through the class II IL-8R in non-hematopoietic cells, this receptor was overexpressed in the 3ASubE human placental and the 293 human kidney cell lines. Membrane preparations of the class II IL-8R expressing 3ASubE transfectants exhibited a 2.3 +/- 0.2-fold increase in GTP gamma 35S binding, which was sensitive to pertussis toxin, in response to MGSA treatment (0.2 microM). This MGSA response was not observed in cells transfected with the parental expression vector. In vivo phosphorylation studies demonstrated that the class II IL-8R was basally phosphorylated in the untreated transfectants, and MGSA (5 nM) treatment markedly enhanced the phosphorylation of this receptor. The MGSA-induced receptor phosphorylation was both time and concentration dependent and could be mimicked by treatment with the calcium ionophore A23187. Phosphoamino acid analysis indicated that the MGSA-induced receptor phosphorylation was on serine residue(s), suggesting that a serine kinase is activated in response to MGSA binding to the class II IL-8R in non-hematopoietic cells.
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PMID:Melanoma growth stimulatory activity enhances the phosphorylation of the class II interleukin-8 receptor in non-hematopoietic cells. 829 49

We studied the involvement of chemokines that bind to G protein-coupled receptors in the migration of skin homing T cells across a bilayer vascular construct (BVC) consisting of a fibroblast matrix underneath an activated endothelial (EC) monolayer. Based on the expression of the cutaneous lymphocyte-associated antigen (CLA), a skin homing receptor, CD45R0+ T cells freshly isolated from blood or HUT-78 cutaneous T lymphoma cells were separated into CLA+ and CLA- subpopulations. These T cells were incubated on interleukin (IL)-1 beta and tumor necrosis factor-alpha-activated EC, and the number of transmigrated cells was determined. The chemokine IL-8 was selectively involved in the enhanced migration of CLA+ T cells across activated EC as demonstrated by blocking antibody to IL-8 but not to GRO-alpha, MCP-1 and RANTES. Identical results were obtained with both human umbilical vein EC (HUVEC) and microvascular skin EC (HDMEC). Pertussis toxin selectively inhibited the enhanced transendothelial migration (TEM) of CLA+ T cells, suggesting that CLA-dependent TEM depends on Gi protein-transmitted signals. Moreover, the IL-8 receptor B (IL-8RB) appeared to be functionally involved in TEM, as demonstrated by receptor desensitization with the CXC chemokines IL-8 and GRO-alpha and by blocking the IL-8RB with specific monoclonal antibodies. Although only the IL-8RB was involved in CLA-dependent TEM, mRNA encoding IL-8RA and IL-8RB was expressed by both CLA+ and CLA- T cells. This correlated with IL-8RA and IL-8RB surface expression on these cells. Thus, the IL-8RB is selectively functional in TEM of T cells expressing the skin homing receptor CLA. Our results demonstrate a critical role for IL-8 and possibly other IL-8RB ligands in addition to the IL-8RB in TEM and suggest the involvement of these molecules in the homing of specific T cells to inflamed skin.
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PMID:The interleukin-8 receptor B and CXC chemokines can mediate transendothelial migration of human skin homing T cells. 881 46

Human granulocyte chemotactic protein 2 (GCP-2) has originally been isolated from cytokine-stimulated osteosarcoma cells as a chemokine coproduced in minute amounts together with interleukin 8. Human GCP-2 (75 residues) was synthesized on a 0.25-mmol scale using Fmoc chemistry. After disulfide bridge formation and purification, monomeric GCP-2 was recovered as a 6-kDa protein; the pure synthetic protein showed a molecular mass of 8076 Da as determined by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The exact amino acid sequence of synthetic GCP-2 was confirmed by Edman degradation. Synthetic GCP-2 was an equally active (minimal effective concentration of 1-3 nM) chemoattractant for neutrophilic granulocytes as was natural 75-residue GCP-2. At concentrations up to 30 nM, synthetic GCP-2 did not stimulate eosinophil, monocyte, or lymphocyte chemotaxis. GCP-2 induced a dose-dependent increase in [Ca2+]i in neutrophils, 1 nM being the minimal effective concentration. The GCP-2-induced [Ca2+]i increase was completely prevented by pertussis toxin. Prestimulation of neutrophils with equimolar concentrations of purified natural IL-8, GROalpha, GROgamma and ENA-78 abolished the [Ca2+]i increase in response to 1 nM GCP-2. Alternatively, the [Ca2+]i rise induced by these CXC chemokines was inhibited by pretreatment of neutrophils with GCP-2. GCP-2 stimulated [Ca2+]i increases in CXCR1- and CXCR2-transfected cells, demonstrating that GCP-2 binds to both IL-8 receptors. Intradermal injection of synthetic GCP-2 resulted in a dose-dependent neutrophil accumulation and plasma extravasation in rabbit skin. To provoke this skin reaction, GCP-2 (10 pmol/site) was nearly as effective as IL-8, indicating that it is an important complementary mediator of the inflammatory response.
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PMID:Characterization of synthetic human granulocyte chemotactic protein 2: usage of chemokine receptors CXCR1 and CXCR2 and in vivo inflammatory properties. 905 80

Dendritic cells are potent antigen-presenting cells involved in the initiation of immune responses. The trafficking of these cells to tissues and lymph nodes is mediated by members of the chemokine family. Recently, a novel CC chemokine known as MIP-3alpha or liver and activation-regulated chemokine has been identified from the EMBL/GenBank/DDBJ expressed sequence tag database. In the present study, we have shown that the messenger RNA for MIP-3alpha is expressed predominantly in inflamed and mucosal tissues. MIP-3alpha produced either synthetically or by human embryonic kidney 293 cells is chemotactic for CD34(+)-derived dendritic cells and T cells, but is inactive on monocytes and neutrophils. MIP-3alpha was unable to displace the binding of specific CC or CXC chemokines to stable cell lines expressing their respective high affinity receptors, namely CCR1-5 and CXCR1 and CXCR2, suggesting that MIP-3alpha acts through a novel CC chemokine receptor. Therefore, we used degenerate oligonucleotide-based reverse transcriptase PCR to identify candidate MIP-3alpha receptors in lung dendritic cells. Our results show that the orphan receptor known as GCY-4, CKRL-3, or STRL-22 is a specific receptor for MIP-3alpha, and that its activation leads to pertussis toxin-sensitive and phospholipase C-dependent intracellular Ca2+ mobilization when it is expressed in HEK 293 cells.
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PMID:Cloning and characterization of a specific receptor for the novel CC chemokine MIP-3alpha from lung dendritic cells. 929 37

The involvement of basic residues of interleukin(IL)-8 receptors in coupling to the Gi and G16 proteins was investigated by using a series of IL-8 receptor mutants. Substitution of the basic amino acids in the third inner loop of the receptor does not alter the abilities of the receptor mutants to activate recombinant Galpha16 or phosphoinositide-specific phospholipase C (PLC) beta2 expressed in COS-7 cells. However, an IL-8 receptor mutant with double mutations at residues Lys158 and Arg159 of the second inner loop loses its abilities to activate Galpha16 but retains its ability to activate PLC beta2. The activation of PLC beta2 by an IL-8 receptor that is sensitive to pertussis toxin has been previously demonstrated to be mediated through Gbetagamma. Surprisingly, the IL-8 receptor mutants with substitution of Ala for either residue Lys158 or Arg159 can still activate Galpha16, which suggests that either of the two basic residues in the second inner loop of the IL-8 receptor is sufficient for Galpha16 coupling.
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PMID:Two basic amino acids in the second inner loop of the interleukin-8 receptor are essential for Galpha16 coupling. 931 98

Activation of the serine/threonine kinase Akt, also called protein kinase B (PKB), was investigated in human neutrophils. Stimulation of the cells with the chemoattractant fMet-Leu-Phe or the chemokines IL-8 and GROalpha leads to the rapid and transient activation of PKB. Maximum PKB activation correlates with the well documented kinetics of respiratory burst and exocytosis. Wortmannin, a selective inhibitor of phosphoinositide 3-kinases (PI 3-kinases) in neutrophils, abrogates PKB activation. Similarly homo and heterotypic cross-linking of FcgammaIIA and FcgammaIIIB causes a transient activation of PKB that is sensitive to wortmannin treatment. Kinase activity measurements in immunoprecipitates from lysates of the myelocytic GM-1 cells or GM-1/CXCR1 cells, which are transfected with the IL-8 receptor 1, confirmed the transient activation of PKB observed in neutrophils. Stimulation of human monocytes with the CC chemokine RANTES (regulated on activation normal T cell expressed and secreted) also results in the activation of PKB. Preincubation of monocytes and neutrophils with Bordetella pertussis toxin inhibits fMet-Leu-Phe and RANTES-stimulated PKB activation, demonstrating that coupling of the receptors to heterotrimeric Gi-protein is required. The data show, that activation of PKB by Gi-protein-coupled receptors is mediated by PI 3-kinase and suggest that PKB is a constituent of neutrophil activating pathways.
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PMID:G-Protein-coupled receptors and Fcgamma-receptors mediate activation of Akt/protein kinase B in human phagocytes. 934 64

Interleukin-8 (IL-8) receptor A (CXCR1) couples to a pertussis toxin-sensitive G protein to mediate phospholipase Cbeta (PLCbeta) activation and cellular responses. Responses to CXCR1 are attenuated by prior exposure of neutrophils to either IL-8, a cleavage product of the fifth component of complement (C5a) or n-formylated peptides (formylmethionylleucylphenylalanine, fMLP). To characterize the role of receptor phosphorylation in the regulation of the CXCR1, a phosphorylation-deficient mutant, M2CXCR1, was constructed. This receptor, stably expressed in RBL-2H3 cells, coupled more efficiently to G protein and stimulated enhanced phosphoinositide hydrolysis, cAMP production, exocytosis, and phospholipase D activation, and was resistant to IL-8-induced receptor internalization. The rate and total amount of ligand stimulated actin polymerization remained unchanged, but interestingly, chemotaxis was decreased by approximately 30% compared with the wild type receptor. To study the role of receptor phosphorylation in cross-desensitization of chemoattractant receptors, M2CXCR1 was coexpressed with cDNAs encoding receptors for either fMLP (FR), C5a (C5aR), or platelet-activating factor (PAFR). Both C5aR and PAFR were cross-phosphorylated upon M2CXCR1 activation, resulting in attenuated guanosine 5'-3'-O-(thio)triphosphate (GTPgammaS) binding in membranes. In contrast, FR and M2CXCR1 were resistant to cross-phosphorylation and cross-inhibition of GTPgammaS binding by other receptors. Despite the resistance of M2CXCR1 to cross-phosphorylation and receptor/G protein uncoupling, its susceptibility to cross-desensitization of its Ca2+ response by fMLP and C5a, was equivalent to CXCR1. Regardless of the enhancement in certain receptor functions in M2CXCR1 compared with the wild type CXCR1, the mutated receptors mediated equivalent PLCbeta3 phosphorylation and cross-desensitization of Ca2+ mobilization by FR, C5aR, and PAFR. The results herein indicate that phosphorylation of CXCR1 regulates some, but not all of the receptors functions. While receptor phosphorylation inhibits G protein turnover, PLC activation, Ca2+ mobilization and secretion, it is required for normal chemotaxis and receptor internalization. Since phosphorylation of CXCR1 had no effect on its ability to induce phosphorylation of PLCbeta3 or to mediate class-desensitization, these activities may be mediated by independently regulated pathways.
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PMID:Multiple signaling pathways of human interleukin-8 receptor A. Independent regulation by phosphorylation. 955 32

An intact chemotactic response is vital for leukocyte trafficking and host defense. Opiates are known to exert a number of immunomodulating effects in vitro and in vivo, and we sought to determine whether they were capable of inhibiting chemokine-induced directional migration of human leukocytes, and if so, to ascertain the mechanism involved. The endogenous opioid met-enkephalin induced monocyte chemotaxis in a pertussis toxin-sensitive manner. Met-enkephalin, as well as morphine, inhibited IL-8-induced chemotaxis of human neutrophils and macrophage inflammatory protein (MIP)-1alpha, regulated upon activation, normal T expressed and secreted (RANTES), and monocyte chemoattractant protein 1, but not MIP-1beta-induced chemotaxis of human monocytes. This inhibition of chemotaxis was mediated by delta and micro but not kappa G protein-coupled opiate receptors. Calcium flux induced by chemokines was unaffected by met-enkephalin pretreatment. Unlike other opiate-induced changes in leukocyte function, the inhibition of chemotaxis was not mediated by nitric oxide. Opiates induced phosphorylation of the chemokine receptors CXCR1 and CXCR2, but neither induced internalization of chemokine receptors nor perturbed chemokine binding. Thus, inhibition of chemokine-induced chemotaxis by opiates is due to heterologous desensitization through phosphorylation of chemokine receptors. This may contribute to the defects in host defense seen with opiate abuse and has important implications for immunomodulation induced by several endogenous neuropeptides which act through G protein-coupled receptors.
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PMID:Opiates transdeactivate chemokine receptors: delta and mu opiate receptor-mediated heterologous desensitization. 967 44


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