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

The regulation of the cytoskeletal localization of guanine-nucleotide-binding protein alpha i subunits by formyl peptide receptors was studied in myeloid differentiated human leukemia (HL-60) cells. Stimulation of formyl peptide receptors with N-formyl-Met-Leu-Phe (fMet-Leu-Phe) transiently increased the amount of alpha i subunits in the Triton X-100-insoluble cytoskeleton. Similar to the biphasic regulation of the actin content, fMet-Leu-Phe ( > or = 10 nM) rapidly increased the cytoskeletal alpha i content (about threefold at 30 s), which was followed by a rapid reversal to control levels. The formyl peptide receptor increased the cytoskeletal content of both alpha i subtypes, alpha i2 and alpha i3- present in HL-60 cells. In cells permeabilized with Staphylococcus aureus alpha-toxin, fMet-Leu-Phe increased binding of the stable GTP analogue, guanosine 5'-[gamma-thio]triphosphate (GTP[S]), to cytoskeletal proteins in a pertussis-toxin-sensitive manner, which was completely abolished by the F-actin-disrupting agent, cytochalasin B. Using the photoreactive GTP analogue, m-acetylanilido-GTP, the formyl peptide receptor-regulated GTP binding sites at the cytoskeleton were identified as 40-kDa proteins, the molecular size of alpha i subunits. Cytoskeleton prepared from stimulated cells did not exhibit increased GTP[S] binding, which suggests that activated alpha i subunits are translocated to the cytoskeleton. Finally, in alpha-toxin-permeabilized HL-60 cells, fMet-Leu-Phe and GTP[S] cooperatively stimulated actin polymerization. In conclusion, evidence is provided that chemoattractant receptors cause translocation of activated alpha i subunits to the cytoskeleton coincidentally with F-actin formation. The data therefore argue for a potential role of translocated alpha i subunits in the process of receptor-induced actin polymerization.
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PMID:Receptor-induced translocation of activated guanine-nucleotide-binding protein alpha i subunits to the cytoskeleton in myeloid differentiated human leukemia (HL-60) cells. 877 23

Cellular cyclic AMP formation in response to prostaglandin (PG) E1 was markedly potentiated by the chemoattractant formyl-Met-Leu-Phe (fMLP) in guinea pig neutrophils. This potentiation by fMLP was abolished by prior treatment of the cells with pertussis toxin, but not by the prevention of an fMLP-induced intracellular Ca2+ increase in the cells, indicating the direct involvement of the inhibitory GTP-binding protein (Gj), but not Ca2+, in the fMLP-induced potentiation of cyclic AMP formation. Cyclic AMP formation in the neutrophils was also unique in response to forskolin; the diterpene inhibited cyclic AMP formation stimulated by PGE1 plus fMLP at low concentrations, but it slightly stimulated the basal and fMLP-induced cyclic AMP formation at high concentrations. Such a forskolin-induced inhibition was also observed in the adenylyl cyclase of the cell membranes and detergent extract therefrom only when the cyclase was activated by GTP or its nonhydrolyzable analogue (GTP gamma S). The forskolin-inhibitable activity could be affinity-purified from the GTP gamma S-treated cell membranes with a forskolin-agarose column. The cyclase appeared to be purified as a complex with the GTP gamma S-bound alpha subunit of the stimulatory GTP-binding protein (Gs alpha), but not with the beta gamma subunits, as judged from immunoblot analysis with specific antisera. The GTP gamma S-bound Gs alpha-stimulated cyclase activity was further enhanced by beta gamma, and this enhancement was again inhibited by forskolin. These results suggest that the GTP-bound Gs alpha produced by PGE1 receptor stimulation and the beta gamma subunits released from Gj by fMLP receptor stimulation were acting synergistically in the cyclic AMP formation of intact neutrophils.
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PMID:Involvement of the beta gamma subunits of inhibitory GTP-binding protein in chemoattractant receptor-mediated potentiation of cyclic AMP formation in guinea pig neutrophils. 878 52

Microglial cells respond to most pathological events by rapid transformation from a quiescent to an activated phenotype characterized by increased cytotoxicity and motile activity. To investigate the regulation of microglial motility by different inflammatory mediators, we studied cultured murine microglia by time-lapse video microscopy and a computer-based motility assay. Microglial cells exhibited a high resting motility. The acute application of complement 5a (C5a) immediately induced intense ruffling of microglial membranes followed by lamellipodia extension within few seconds, while formyl-Met-Leu-Phe-OH, bacterial endotoxin (lipopolysaccharide) or inflammatory cytokines did not increase motility. This process was accompanied by a rapid rearrangement of the actin cytoskeleton as demonstrated by labelling with fluorescein isothiocyanate-phalloidin and could be inhibited by cytochalasin B. A GTP-binding protein was involved in the signal cascade, since pertussis toxin inhibited motility and actin assembly in response to C5a. Chemotactic migration in a gradient of C5a was also completely blocked by pertussis toxin and cytochalasin B. The C5a-induced motility reaction was accompanied by an increase in intracellular calcium ([Ca2+]i) as measured by a Fluo-3 based imaging system. Ca2+ transients were, however, not a prerequisite for triggering the increase in motility; motility could be repeatedly evoked by C5a in nominally Ca(2+)-free solution, while Ca2+ signals occurred only upon the first stimulation. Moreover, conditions mimicking intracellular Ca2+ transients, like incubation with thapsigargin or Ca2+ ionophore A23187, were not able to induce any motility reaction, suggesting that Ca2+ transients are not necessary for, but are associated with, microglial motility. Motile activity was shown to be restricted to a defined concentration range of [Ca2+]i as revealed by lowering [Ca2+]i with BAPTA-AM or increasing [Ca2+]i with A23187. Since complement factors are released at pathological sites, this signal cascade could serve to increase motility and to direct microglial cells to the lesioned or damaged area by means of a G-protein-dependent pathway and via the rearrangement of the actin cytoskeleton.
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PMID:Complement 5a controls motility of murine microglial cells in vitro via activation of an inhibitory G-protein and the rearrangement of the actin cytoskeleton. 880 27

The 220 kDa filamentous haemagglutinin (FHA) is a major adhesin of Bordetella pertussis and is produced from a large precursor designated FhaB. Although partly surface associated, it is also very efficiently secreted into the extracellular milieu. Its secretion depends on the outer membrane accessory protein FhaC. An 80 kDa N-terminal derivative of FHA, named Fha44, can also be very efficiently secreted in a FhaC-dependent manner, indicating that all necessary secretion signals are localized in the N-terminal region of FhaB. A comparison of predicted and apparent sizes of FHA derivatives, in addition to immunoblot analyses of cell-associated and secreted FHA polypeptides, indicated that FhaB undergoes N-terminal maturation by the cleavage of an 8-9 kDa segment. However, phenotypic analyses of translational lacZ and phoA fusions showed that this segment does not function as a typical signal peptide. Co-expression of the Fha44-encoding gene with fhaC also did not allow for secretion of Fha44 in Escherichia coli. High levels of secretion could, however, be observed when the OmpA signal peptide was fused to the N-terminal end of Fha44. Regardless of the OmpA signal peptide-Fha44 fusion point, the E. coli-secreted Fha44 had the same M(r) as that secreted by B. pertussis, indicating that the N-terminal proteolytic maturation does not require a B. pertussis-specific factor. Similar to FHA, the B. pertussis-secreted Fha44 contains an as yet uncharacterized modification at its N-terminus. This modification did not occur in E. coli and is therefore not required for secretion. The N-terminus of Fha44 secreted by E. coli was determined and found to correspond to the 72nd residue after the first in-frame methionine of FhaB. The N-terminal modification was also found not to be required for haemagglutination or interaction with sulphated glycoconjugates.
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PMID:Amino-terminal maturation of the Bordetella pertussis filamentous haemagglutinin. 882 37

The sensory neuropeptide secretoneurin (SN) triggers chemotactic migration of monocytes. We have investigated the possibility that SN, like other chemoattractants such as formyl-Met-Leu-Phe and chemokines, might stimulate migration of monocytes by G protein and protein kinase C (PKC) activation and induce Ca2+i release. We report that preincubation of monocytes with pertussis toxin inhibited SN chemotaxis. Staurosporine, an inhibitor of PKC, significantly decreased SN-induced chemotaxis of monocytes, suggesting that PKC may be involved in the signaling. Tyrphostin-23, which inhibits tyrosin kinase, did not affect SN-induced chemotaxis of monocytes. This suggests that SN uses a signaling mechanism that is coupled to pertussis toxin-sensitive G proteins. Involvement of phospholipase C beta as a result of PKC activation is suggested by a SN-induced increase of intracellular Ca2+ concentration in monocytes.
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PMID:Secretoneurin-induced in vitro chemotaxis of human monocytes is inhibited by pertussis toxin and an inhibitor of protein kinase C. 887 21

We studied the effect of the adenylate cyclase activator forskolin, of protein kinase C-activating phorbol esters and of prolonged preganglionic input activation on the inhibitory response of the perfused superior cervical ganglion of the cat to exogenous met-enkephalin (Met-ENK). Met-ENK inhibited, in a concentration-dependent manner, the postganglionic compound action potential evoked by cervical sympathetic trunk stimulation. The inhibition was reversible, was blocked by naloxone as well as by pertussis toxin and showed no homologous desensitization in the concentration range 0.01-10 microM. Pretreatment of the ganglion with 4 beta-phorbol 12,13-dibutyrate or 4 beta-phorbol 12,13-diacetate depressed the Met-ENK response for several hours, while pretreatment with forskolin had no effect. This action of phorbol esters was prevented by the protein kinase inhibitor H-7 but not by the calmodulin antagonist W-7 or the protein kinase A inhibitor HA 1004 and was calcium-dependent. Recovery of the response from the depression produced by phorbol esters was not affected by a protein synthesis inhibitor. A 40 Hz 20 min stimulus train to the cervical sympathetic trunk mimicked the effect of phorbol esters, depressing for several hours the inhibition produced by Met-ENK. Stimulus trains of duration shorter than 5 min or frequency lower than 5 Hz were ineffective. This effect of prolonged preganglionic stimulation occurred even when the stimulus train was delivered during complete block of nicotinic and muscarinic ganglionic transmission but was lost when the stimulus train was delivered during perfusion with calcium-free Krebs. The protein kinase inhibitor H-7 prevented the depression of the Met-ENK response by the train, while W-7 and HA 1004 had no effect. These findings suggest that, in the superior cervical ganglion of the cat, a kinase, activated by phorbol esters and inhibited by H-7, exerts a long-term control of the ganglion cell responsiveness to opiate receptor activation. A similar mechanism can be synaptically activated by a non-cholinergic transmitter, released by the preganglionic axons during prolonged, high frequency, activity.
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PMID:Long-term depression of a sympathetic ganglionic response to opioids by prolonged synaptic activity and by phorbol esters. 896 46

Mechanisms of neutrophil activation in response to chemoattractants remain incompletely understood. We have recently reported a Ras-mediated c-Raf pathway leading to the activation of mitogen-activated protein (MAP) kinase in human neutrophils stimulated with the chemoattractant formyl-Met-Leu-Phe (FMLP). However, concern that Raf activation may not fully account for the early FMLP-mediated human neutrophil responses prompted us to investigate the activation of MAP kinase/ERK kinase (MEK) by MEK kinase (MEKK). In cell lysates we identified protein species at 180, 160, 110, 72, and 54 kDa with a monoclonal antibody to MEKK. Activation of MEKK was determined on immunoprecipitates from FMLP-stimulated neutrophils by in vitro kinase assay, which utilized both MEK1 and MEK2 as substrates. It was rapid, detectable at 30 s and reaching a plateau at 5 min, and it was inhibited in a dose-dependent fashion by a specific phosphatidylinositol 3-kinase inhibitor, wortmannin. Partial inhibition by pertussis toxin was observed. We were unable to show inhibition of the MEKK response by GF 109203X, a protein kinase C-specific inhibitor. These data indicate that in neutrophils activation of MEKK in addition to Raf may underlie stimulation of MAP kinase and other MAP kinase homologues by FMLP.
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PMID:Activation of MEKK by formyl-methionyl-leucyl-phenylalanine in human neutrophils. Mapping pathways for mitogen-activated protein kinase activation. 896 28

Previously, we identified peptides that stimulate phosphoinositide hydrolysis in several leukocyte cell lines from mixtures of random hexapeptide sequences. Moreover, the peptides activate phospholipase C via a pertussis toxin-sensitive G protein-coupled receptor. We now investigate the structure-activity relationship of the peptides with the goal of improving the activity of the peptides, as well as the biologic function of the peptides. Substitution of the L-methionine at the C terminus of peptides with D-methionine markedly increased the effectiveness of the peptides. The half-maximal effective concentrations of MKYMPm-NH2 and WKYMVm-NH2 for stimulation of phosphoinositide hydrolysis in U266 cells were 30 and 0.5 nM, respectively. By BIAcore analysis we confirmed the existence of a receptor for WKYMVm-NH2. Furthermore, the intracellular calcium concentration increase induced by WKYMVm-NH2 was not inhibited by several chemoattractants (FMLP, IL-8, platelet-activating factor, C5a, granulocyte-macrophage CSF, and granulocyte CSF) suggests that WKYMVm-NH2 has a unique cell surface receptor on leukocytes. WKYMVm-NH2 stimulated the phosphoinositide hydrolysis in U937, HL60, and U266 cells, as well as in human neutrophils. Moreover, WKYMVm-NH2 is more effective than FMLP in the production of superoxide in human neutrophils. The data suggest that WKYMVm-NH2 may have the ability to activate the microbicidal functions of human neutrophils.
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PMID:A peptide with unique receptor specificity: stimulation of phosphoinositide hydrolysis and induction of superoxide generation in human neutrophils. 902 31

Neutrophils play a major role in the host defence by producing reactive oxygen species. These products are liberated by activated cells and are known to cause endothelial cell injury and damage. The present study shows that low-density lipoproteins increase superoxide anion production by twofold in polymorphonuclear leukocytes stimulated by formyl-Met-Leu-Phe in vitro. Moreover, LDL induced a large increase in phosphoinositides and cytosolic-free calcium. Data from experiments performed on neutrophils treated with pertussis toxin, staurosporine, propranolol or niflumic acid suggest that modulation of phospholipase D and A2 activities could be involved in the modification by LDL of leukocyte response to formyl-Met-Leu-Phe. LDL lipid moiety could play a key role in their action on polymorphonuclear functions because cholesterol was exchanged between lipoproteins and cells that can modify membrane fluidity and interact with the formyl-Met-Leu-Phe receptor.
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PMID:Effects of human low-density lipoproteins on superoxide production by formyl-methionyl-leucyl-phenylalanine activated polymorphonuclear leukocytes. 905 46

We studied the chemotactic effects of calcitonin gene-related peptide, vasoactive intestinal peptide, substance P (SP), and secretoneurin on PBMC and PBL using micropore filter assays. All four peptides induced migration of PBMC, whereas only calcitonin gene-related peptide, vasoactive intestinal peptide, and SP were chemotactic for PBL. Secretoneurin, known to induce monocyte chemotaxis, was unable to affect lymphocyte migration. Effects of SP on PBL were characterized by checkerboard analyses and represented true chemotaxis. Both T and B cells responded chemotactically to SP, the functional activity of SP residing in its C-terminal amino acid sequence. Involvement of neurokinin (NK) receptors was supported by inhibition of SP-induced migration of PBL with an NK1 receptor antagonist and induction of migration with [Sar9, Met(O2)11]SP and [PyrGlu6, Pro9]SP(6-11), two specific agonists for NK1 receptors, but not with [beta-Ala8]NK A(4-10), an agonist for NK2 receptors. PBL chemotaxis to SP was abolished by inhibition of tyrosin kinase but not by that of protein kinase C. Preincubation of PBL with pertussis or cholera toxin inhibited SP chemotaxis, indicating that in PBL, NK receptors for chemotaxis probably are coupled with G protein and involve a tyrosin kinase signaling pathway. We conclude that, together with calcitonin gene-related peptide and vasoactive intestinal peptide, SP is a lymphocyte chemoattractant, whereas secretoneurin, which is coreleased from sensory nerve endings, is not.
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PMID:Differential chemotactic activities of sensory neuropeptides for human peripheral blood mononuclear cells. 910 59


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