Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Lipoxin A4 (LXA4) triggers selective responses with human neutrophils that are pertussis toxin sensitive and binds to high affinity receptors (Kd = 0.5 +/- 0.3 nM) that are modulated by stable analogues of guanosine 5'-triphosphate (GTP). Here, we characterized [11,12-(3)]LXA4 specific binding with neutrophil granule and plasma membranes, which each display high affinity binding sites (Kd = 0.7 +/- 0.1 nM) that were regulated by GTP gamma S. Since functional LXA4 receptors are inducible in HL-60 cells, we tested orphan cDNAs encoding 7-transmembrane region receptors cloned from these cells for their ability to bind and signal with LXA4. Chinese hamster ovary (CHO) cells transfected with the orphan receptor cDNA (pINF114) displayed specific 3H-LXA4 high affinity binding (1.7 nM). When displacement of LXA4 binding with pINF114-transfected CHO cells was tested with other eicosanoids, including LXB4, leukotriene D4 (LTD4), LTB4, or prostaglandin E2, only LTD4 competed with LXA4, giving a Ki of 80 nM. In transfected CHO cells, LXA4 also stimulated GTPase activity and provoked the release of esterified arachidonate, which proved to be pertussis toxin sensitive. These results indicate that pINF114 cDNA encodes a 7-transmembrane region-containing protein that displays high affinity for 3H-LXA4 and transmits LXA4-induced signals. Together, they suggest that the encoded protein is a candidate for a LXA4 receptor in myeloid cells.
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PMID:Identification of a human cDNA encoding a functional high affinity lipoxin A4 receptor. 800 86

The rabbit neutrophil N-formyl peptide receptor (FPR) has been well studied for its ligand binding properties. Recent gene cloning experiments have established the existence of a subfamily of G protein-coupled receptors that share extensive sequence homology with the FPR, yet lack the capability of high affinity binding to FMLP. These findings prompted us to identify the structural requirement for formyl peptide ligand binding by delineation of the primary structure of the rabbit FPR. A rabbit neutrophil cDNA library was screened with a cloned human FPR cDNA probe and the insert of one positive isolate (B6) was sequenced. The 1268-bp cDNA insert encodes a peptide of 352 amino acids. Stably transfected L cell fibroblasts expressing the rabbit cDNA displayed specific binding of the ligand fMet-Leu-[3H]Phe with two affinities (Kd = 0.31 and 7.5 nM). Addition of the nonhydrolyzable guanosine triphosphate analogue, GTP gamma S, converted > or = 85% of the high affinity sites to the low affinity sites. FMLP induced mobilization of intracellular calcium in the transfected cells (EC50 = 0.5 nM), a response sensitive to pertussis toxin. FMLP stimulation desensitized the receptor such that subsequent stimulation with the same ligand produced a significantly reduced signal. These results indicate that the cloned rabbit receptor represents a high affinity FPR, and that FPR-mediated early signal transduction events can be fully reconstituted in transfected mammalian cells. The rabbit FPR sequence is 78% identical to that of the human FPR, and 68% identical to FPR2, a homologue of FPR with a low binding affinity (Kd > or = 400 nM) for FMLP. Analysis of the aligned sequences of these three proteins revealed that: 1) the amino termini and the second extracellular loops have the lowest sequence homology; 2) sequence in the intracellular domains that couple to G protein are highly conserved; and 3) the first and the third extracellular loops and their adjacent transmembrane domains of the FPR may contain residues essential for the high affinity binding of FMLP.
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PMID:The rabbit neutrophil N-formyl peptide receptor. cDNA cloning, expression, and structure/function implications. 843 84

Lipoxins (LX) are bioactive eicosanoids that activate human monocytes and inhibit neutrophils. LXA4 is rapidly converted by monocytes to inactive products, and to resist metabolism, synthetic analogs of LXA4 were designed. Here, we examined the bioactivity of several LXA4 analogs in monocytes and found, for chemotaxis, 15(R/S)-methyl-LXA4 and 15-epi-LXA4 were equal in activity, and 16-phenoxy-LXA4 was more potent than native LXA4. Both 15(R/S)-methyl-LXA4 and 16-phenoxy-LXA4 were approximately 1 log molar more potent than LXA4 in stimulating THP-1 cell adherence (EC50 approximately 1 x 10(-10) M). Dimethylamide derivatives of the LXA4 analogs also possessed agonist rather than antagonist properties for monocytes. Neither LXA4 nor 16-phenoxy-LXA4 affected monocyte-mediated cytotoxicity. We cloned an LXA4 receptor from THP-1 cells identical to that found in PMN. Evidence of receptor-mediated function of LXA4 and the stable analogs in monocytes included desensitization of intracellular calcium mobilization to a second challenge by equimolar concentrations of these analogs, but not to LTB4. Increases in [Ca2+]i by LXA4 and the analogs were specifically inhibited by an antipeptide antibody to the LXA4 receptor; and both LXA4- and analog-induced adherence and increments in Ca2+ were sensitive to pertussis toxin. Together, these results indicate that the LXA4 stable analogs are potent monocyte chemoattractants and are more potent than native LXA4 in stimulating THP-1 cell adherence, at subnanomolar concentrations. Moreover, they provide additional evidence that the LXA4 stable analogs retain selective bioactivity in monocytes and are valuable instruments for examining the functions and modes of action of LXA4.
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PMID:Lipoxin A4 stable analogs are potent mimetics that stimulate human monocytes and THP-1 cells via a G-protein-linked lipoxin A4 receptor. 905 86

Human phagocytic leukocytes express the seven-transmembrane G-protein-coupled receptors formyl peptide receptor (FPR) and FPR-like 1 (FPRL1). MMK-1, a synthetic peptide derived from a random peptide library, is reported to induce calcium mobilization specifically in human FPRL1 gene-transfected cells. However, its actions on human phagocytic leukocytes remain poorly defined. We found that MMK-1 is a potent chemotactic and calcium-mobilizing agonist for human monocytes, neutrophils, and FPRL1-transfected human embryonic kidney (HEK) 293 cells but is inactive in cells transfected with FPR. MMK-1 also activated HEK 293 cells transfected with FPR2, a mouse counterpart of human FPRL1. Furthermore, MMK-1 increased pertussis toxin-sensitive production of inflammatory cytokines in human monocytes. MMK-1 signaling in human phagocytes was completely desensitized by a well-defined FPRL1 agonist, suggesting that FPRL1 is likely a receptor that mediates the action of MMK-1 in primary cells. Since MMK-1 is one of the most potent FPRL1-specific agonists identified so far, it can serve as a modulator of the host defense and a useful agent for further studying the signaling and function of FPRL1.
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PMID:Synthetic peptide MMK-1 is a highly specific chemotactic agonist for leukocyte FPRL1. 1143 99

Aspirin-triggered 15-epi-lipoxin A4 (ATL) is an endogenous lipid mediator that mimics the actions of native lipoxin A4, a putative "stop signal" involved in regulating resolution of inflammation. A metabolically more stable analog of ATL, 15-epi-16-(para-fluoro)-phenoxy-lipoxin A4 analog (ATLa), inhibits neutrophil recruitment in vitro and in vivo and displays potent anti-inflammatory actions. ATLa binds with high affinity to the lipoxin A4 receptor, a G protein-coupled receptor on the surface of leukocytes. In this study, we used freshly isolated human neutrophils to examine ATLa's potential for initiating rapid nuclear responses. Using differential display reverse transcription polymerase chain reaction, we identified a subset of genes that was selectively up-regulated upon short exposure of polymorphonuclear leukocytes to ATLa but not to the chemoattractant leukotriene B4 or vehicle alone. We further investigated ATLa regulation of one of the genes, NAB1, a transcriptional corepressor identified previously as a glucocorticoid-responsive gene in hamster smooth muscle cells. Treatment of human neutrophils with pertussis toxin blocked ATLa up-regulation of NAB1. In addition, ATLa stimulated NAB1 gene expression in murine lung vascular smooth muscle in vivo. These findings provide evidence for rapid transcriptional induction of a cassette of genes via an ATLa-stimulated G protein-coupled receptor pathway that is potentially protective and overlaps with the anti-inflammatory glucocorticoid regulatory circuit.
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PMID:Aspirin-triggered lipoxin A4 and lipoxin A4 up-regulate transcriptional corepressor NAB1 in human neutrophils. 1168 10

Lipoxins, endogenous eicosanoids biosynthetized in vivo at inflammation sites, are potential antiinflammatory mediators. Subjects with severe asthma present chronic inflammation of the airways despite long-term treatment with oral glucocorticoids. Therefore it is of interest to investigate the potential antiinflammatory effects of lipoxin A4 (LXA4) and lipoxin B4 (LXB4) that could attenuate chronic inflammation. In a first time, we detected interleukin (IL)-8 and LXA4 in supernatants of induced sputum. IL-8 was heightened in severe asthma (p = 0.001), whereas high concentrations of lipoxin A4 were present in mild asthma (p = 0.001). We then studied the effects of LXA4 on IL-8 released in vitro. Nanomolar concentrations of LXA4 and LXB4 inhibited the IL-8 released by peripheral blood mononuclear cells from the two groups of patients with asthma: a maximal inhibition of 29.4% (p < 0.01) was observed for patients with mild asthma, and 41.5% inhibition (p < 0.001) for patients with severe asthma at 1 nM and 100 nM LXA4 concentrations, respectively. Polymerase chain reaction analysis indicated that peripheral blood mononuclear cells from patients with asthma expressed the LXA4 receptor mRNA. Moreover, pertussis toxin reversed LXA4- and LXB4-inhibited IL-8 release. These findings suggest that lipoxins have potential antiinflammatory action in asthma.
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PMID:Lipoxins are potential endogenous antiinflammatory mediators in asthma. 1204 28

The lipoxygenase-derived leukotrienes (LTs) are important proinflammatory lipid mediators. Lipoxins (LXs), more recently described lipoxygenase products, modulate many proinflammatory actions of LTs and have impressive proresolution properties. Mesangial cell (MC) proliferation is a central event in the pathogenesis of glomerulonephritis. LTD4-induced proliferation of mesangial cells is modulated by LXA4. Here, we demonstrate that LXA4 inhibits PDGF- and LTD4-stimulated proliferation through modulation of platelet-derived growth factor receptor beta (PDGFRbeta) activation. Specifically, we demonstrate that LTD4 transactivates the PDGFRbeta, a process associated with c-src recruitment and ras activation. We demonstrate expression of cysLT1 and cysLT2 receptors in MCs. LTD4-induced c-src activation was insensitive to pertussis toxin and the cysLT1 receptor antagonist Zafirlukast but was blocked by the nonselective antagonist Pobilukast. We show that LXA4 inhibits LTD4-stimulated activation of the PDGFRbeta and that LXA4 modulates PDGF-BB-stimulated tyrosine phosphorylation of the PDGFRb and subsequent mitogenic events. Furthermore, expression of recombinant LXA4 receptor (ALXR) in CHOK1 cells was associated with an attenuation of serum-stimulated proliferation. These data demonstrate that LXA4 receptor (ALXR) activation is accompanied by antimitogenic effects coupled with inactivation of growth factor receptors, highlighting the complex cross-talk between G protein-coupled receptors and receptor tyrosine kinases in an inflammatory milieu. These data elaborate on the profile of cell signaling events that underpin the anti-inflammatory and proresolution bioactions of LX.
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PMID:Lipoxin, leukotriene, and PDGF receptors cross-talk to regulate mesangial cell proliferation. 1222 54

Many mammalian antimicrobial peptides (AMPs) have multiple effects on antimicrobial immunity. We found that temporin A (TA), a representative frog-derived AMP, induced the migration of human monocytes, neutrophils, and macrophages with a bell-shaped response curve in a pertussis toxin-sensitive manner, activated p44/42 MAPK, and stimulated Ca(2+) flux in monocytes, suggesting that TA is capable of chemoattracting phagocytic leukocytes by the use of a G(ialpha) protein-coupled receptor. TA-induced Ca(2+) flux in monocytes was cross-desensitized by an agonistic ligand MMK-1 specific for formyl peptide receptor-like 1 (FPRL1) and vice versa, suggesting that TA uses FPRL1 as a receptor. This conclusion was confirmed by data showing that TA selectively stimulated chemotaxis of HEK 293 cells transfected with human FPRL1 or its mouse ortholog, murine formyl peptide receptor 2. In addition, TA elicited the infiltration of neutrophils and monocytes into the injection site of mice, indicating that TA is also functionally chemotactic in vivo. Examination of two additional temporins revealed that Rana-6 was also able to attract human phagocytes using FPRL1, but temporin 1P selectively induced the migration of neutrophils using a distinct receptor. Comparison of the chemotactic and antimicrobial activities of several synthetic analogues suggested that these activities are likely to rely on different structural characteristics. Overall, the results demonstrate that certain frog-derived temporins have the capacity to chemoattract phagocytes by the use of human FPRL1 (or its orthologs in other species), providing the first evidence suggesting the potential participation of certain amphibian antimicrobial peptides in host antimicrobial immunity.
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PMID:Temporin A and related frog antimicrobial peptides use formyl peptide receptor-like 1 as a receptor to chemoattract phagocytes. 1529 82

Formyl peptide receptor-like 1 (FPRL1) is a G protein-coupled receptor that binds natural and synthetic peptides as well as lipoxin A(4) and mediates important biological functions. To facilitate its pharmacological characterization, we screened a compound library and identified a substituted quinazolinone (Quin-C1, 4-butoxy-N-[2-(4-methoxy-phenyl)-4-oxo-1,4-dihydro-2H-quinazolin-3-yl]-benzamide) as a ligand for FPRL1. Quin-C1 induces chemotaxis and secretion of beta-glucuronidase in peripheral blood neutrophils with a potency of approximately 1/1000 of that of the peptide agonist WKYMVm. In studies using transfected rat basophilic leukemia (RBL) cell lines expressing either formyl peptide receptor or FPRL1, Quin-C1 induced enzyme release from RBL-FPRL1 but not RBL-FPR cells. Likewise, Quin-C1 selectively stimulates calcium mobilization in RBL-FPRL1 cells, a response that was markedly inhibited by pertussis toxin. Quin-C1 also stimulates phosphorylation of extracellular signal-regulated protein kinases 1 and 2 and induces internalization of an FPRL1 fused to green fluorescent protein. In degranulation assays, both the FPRL1-selective peptide agonist MMK1 and Quin-C1 exhibited lower efficacy and potency than WKYMVm, with EC(50) values of 7.17 x 10(-8) M and 1.88 x 10(-6) M, respectively, compared with the EC(50) value for WKYMVm (2.29 x 10(-8) M). However, Quin-C1 did not induce neutrophil superoxide generation at up to 100 microM. Based on these results, we conclude that Quin-C1 is a novel nonpeptide ligand that binds to FPRL1 and selectively stimulates FPRL1-mediated functions. Quin-C1 is a prototype of substituted quinazolinones based on which further structural modifications may be made to improve its efficacy and potency for FPRL1.
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PMID:A novel nonpeptide ligand for formyl peptide receptor-like 1. 1530 62

The urokinase-type plasminogen activator (uPA) receptor (uPAR) functions in concert with co-receptors, including integrins, FPR-like receptor-1/lipoxin A4 receptor, and the epidermal growth factor receptor (EGFR), to initiate cell signaling. uPAR co-receptors may be dynamically organized into a multiprotein signaling receptor complex. In Chinese hamster ovary-K1 (CHO-K1) cells, uPA-binding to uPAR activates ERK/MAP kinase, even though these cells do not express the EGFR; however, when CHO-K1 cells are transfected to express the EGFR, ERK activation becomes EGFR-dependent. In this study, we demonstrate that ERK activation in response to uPA follows equivalent biphasic kinetics in EGFR-expressing and -deficient CHO-K1 cells. In both cell types, the response is pertussis toxin-sensitive; however, uPA promotes cell proliferation exclusively in the EGFR-expressing cells. uPA-induced mitogenic activity requires activation of both STAT5b and ERK. STAT5b was tyrosine-phosphorylated, in response to uPA, only in EGFR-expressing cells. uPA-induced cell proliferation was blocked by dominant-negative MEK1, dominant-negative STAT5b, and by expression of an EGFR that is mutated at Tyr-845, which is essential for STAT5b activation. In two cell culture models of uPA-stimulated breast cancer growth, MDA-MB 468 cells treated with uPA and MCF-7 cells treated with uPA-plasminogen activator inhibitor-1 complex, proliferation was completely inhibited when EGFR expression or activity was blocked. We conclude that expression and assembly of uPAR co-receptors in a specific cell type determines the response to uPA. The EGFR selectively cooperates with uPAR to mediate mitogenesis.
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PMID:Dynamic assembly of the urokinase-type plasminogen activator signaling receptor complex determines the mitogenic activity of urokinase-type plasminogen activator. 1572 76


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