UMLS:C0043167 - FACTA Search

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Query: UMLS:C0043167 (pertussis)
19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human neutrophils treated with pertussis toxin had decreased functional responses to several agents including zymosan-treated serum, heat-aggregated immunoglobulin, platelet-activating factor, and fMet-Leu-Phe. Responses affected include superoxide generation and release of lysozyme. The degree and type of inhibition was dependent on the individual receptor and the cellular response studied. Measurement of intracellular calcium levels with quin-2 showed that both fMet-Leu-Phe- and platelet-activating factor-mediated increases in quin-2 fluorescence were diminished as a result of pertussis toxin treatment. fMet-Leu-Phe-mediated calcium uptake was also inhibited. However, under conditions where fMet-Leu-Phe-mediated effects on cell function were completely abolished, only a partial inhibition of 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester (TMB-8) sensitive calcium uptake was observed. A study of the linked reactions of chemotaxis, capping, and shape change revealed that chemotaxis was inhibited regardless of the chemoattractant utilized (zymosan-treated serum, fMet-Leu-Phe, and platelet-activating factor) and the associated reactions of Con A capping and fMet-Leu-Phe- or Con A-mediated shape change were reduced in pertussis toxin-treated cells. Our results suggest that multiple mediators of inflammation act through a pertussis toxin-sensitive GTP-binding protein that regulates the mobilization of internal calcium as well as calcium uptake and is, in addition, a key control element of shape change, capping, and chemotaxis.
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PMID:A pertussis toxin-sensitive GTP-binding protein in the human neutrophil regulates multiple receptors, calcium mobilization, and lectin-induced capping. 300 14

The effects of pretreatment of rabbit neutrophils with phorbol 12-myristate 13-acetate on the ability of pertussis toxin to catalyze ADP-ribosylation and of fMet-Leu-Phe to activate a high-affinity GTPase in these cell homogenates were examined. The addition of phorbol 12-myristate 13-acetate, but not 4 alpha-phorbol 12,13-didecanoate, to intact cells was found to stimulate by more than 100% the pertussis toxin-dependent ribosylation of a 41 kDa protein (either the alpha-subunit of the 'inhibitory' guanine nucleotide-binding protein N or a closely analogous protein) and to inhibit by more than 60% the activation by fMet-Leu-Phe of the GTPase of the neutrophil homogenates. The addition of fMet-Leu-Phe to intact cells increases the ADP-ribosylation catalyzed by pertussis toxin of the 41 kDa protein. On the other hand, the exposure of neutrophil homogenates to fMet-Leu-Phe results in a decreased level of ADP-ribosylation. This decreased ribosylation reflects a dissociation of the GTP-binding protein oligomer that is not followed by association, possibly because of the release of the alpha-subunit into the suspending media. The implications of these results for the understanding of the mechanism of inhibition of cell responsiveness by phorbol esters and the heterologous desensitization phenomenon are discussed. Prominent among these are the possibilities that (i) the rate of dissociation of the Ni oligomer is affected by the degree of its phosphorylation by protein kinase C, and/or (ii) the dissociated phosphorylated alpha-subunit (the 41 kDa protein) is functionally less active than its dephosphorylated couterpart.
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PMID:Treatment of rabbit neutrophils with phorbol esters results in increased ADP-ribosylation catalyzed by pertussis toxin and inhibition of the GTPase stimulated by fMet-Leu-Phe. 300 12

In reviewing our own and other work, it is clear that pertussis toxin treatment of neutrophils causes a time- and concentration-dependent inhibition of granule enzyme secretion induced by formylmethionylleucylphenylalanine (fMet-Leu-Phe), C5a, leukotriene (LT) B4 and platelet-activating factor (PAF). Chemotaxis, O2- generation, aggregation, and arachidonic acid production induced by fMet-Leu-Phe are also inhibited by pertussis toxin. Granule enzyme release caused by A23187 or phorbol 12-myristate 13-acetate is not inhibited. The inhibition of neutrophil function correlates closely with the NAD-ribosylation of a 41,000-dalton protein in the neutrophil plasma membrane, presumably the GTP-binding regulatory protein Ni. Pertussis toxin treatment prevents or obtunds the increased influx of Ca2+ induced by fMet-Leu-phe and LTB4, but not that caused by stimulation of neutrophils with PAF. Pertussis toxin prevents the receptor-induced breakdown of polyphosphoinositides in intact neutrophils and isolated membrane and prevents or decreases the production of inositol 1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol. The hypothesis advanced by us and others is that pertussis toxin interacts with a GTP-binding regulatory protein identical or similar to Ni, which couples receptor-chemotactic factor interaction to phospholipase C activation. Inhibition of the activation prevents the production of IP3 and the resulting release of Ca2+ from intracellular stores and of 1,2-diacylglycerol and thus, the activation of protein kinase C. The lack of these two mediators is the immediate cause of the depression of neutrophil activation resulting from pertussis toxin. Some of the limitations and uncertainties of our present knowledge with respect to this hypothesis are discussed.
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PMID:Pertussis toxin as a probe of neutrophil activation. 301 23

When stimulated, neutrophils undergo a complex change in cytoplasmic pH (pHi): an incipient acidification, followed by an alkalinization which is due to activation of Na+/H+ exchange. When the latter is inhibited by amiloride or by removal of extracellular Na+, the actual magnitude of the initial acidification can be fully appreciated. The acidification is thought to be of metabolic origin, but the precise origin of the H+ (equivalents) remains undefined. We used adenosine, a modulator of neutrophil responsiveness, to identify the source of metabolic acid in cells stimulated by either formylmethionylleucylphenylalanine (fMet-Leu-Phe) or 12-O-tetradecanoylphorbol 13-acetate (TPA). Pretreatment of the cells with adenosine inhibited the fMet-Leu-Phe-induced respiratory burst, but secretion of specific and azurophilic granules, as well as aggregation were unaffected. In fMet-Leu-Phe-treated cells, adenosine reduced the acidification recorded in Na+-free media, but had no effect on the activation of the Na+/H+ antiport. Adenosine had little or no effect on the TPA-induced responses, including the pHi changes. The respiratory burst, as well as the cytoplasmic acidification were also inhibited in parallel by pretreating the cells with 'islet-activating protein' from Bordetella pertussis. It was concluded that activation of the NADPH-oxidase and/or the associated stimulation of the hexose monophosphate shunt play a major role in the metabolic acidification of stimulated neutrophils.
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PMID:Cytoplasmic pH regulation in activated human neutrophils: effects of adenosine and pertussis toxin on Na+/H+ exchange and metabolic acidification. 302 27

We have examined the role of GTP-binding proteins and the associated cyclic AMP- and calcium-related transduction mechanisms in the regulation of capping in human neutrophils. Pertussis toxin (PT), a probe for the GTP-binding protein Ni, abolished capping induced by fluorescein isothiocyanate-conjugated concanavalin A (Con-A), whereas cholera toxin, a probe for the GTP-binding protein Ns, was without effect. Consistent with the latter finding, ligands acting at receptors associated with the Ns protein, namely the prostaglandin E1 and beta-adrenergic agonists, were without effect on the capping reaction. The possible role of mobilization of internal calcium was evaluated by using Quin2-loaded cells. Calcium mobilization was observed at concentrations of Con-A which yielded optimal capping (10 micrograms/ml). Treatment with PT, phorbol myristrate acetate or 8-(NN-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) abolished both calcium mobilization and capping. Colchicine, which substantially enhanced capping, had no effect on calcium mobilization. At concentrations of the lectin above those required for capping, superoxide generation and enzyme release were noted. These reactions were less susceptible to inhibition by PT, effects being observed only on the Kact. for Con-A-mediated superoxide generation with little effect on the Vmax. The degree of PT-mediated inhibition for enzyme release with Con-A was much lower than that observed with fMet-Leu-Phe. Our results imply that a step involving Ni-mediated calcium mobilization, sensitive to phorbol myristate acetate, is essential to the regulation of capping; a distinct mechanism may be involved in colchicine-mediated enhancement of capping; and Ni may play a relative minor role in the regulation of lectin-mediated exocytosis.
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PMID:Role of a pertussis toxin substrate in the control of lectin-induced cap formation in human neutrophils. 302 44

Guanine nucleotide-binding regulatory proteins (G proteins) transduce a remarkably diverse group of extracellular signals to a relatively limited number of intracellular target enzymes. In the neutrophil, transduction of the signal following fMet-Leu-Phe receptor-ligand interaction is mediated by a pertussis toxin substrate (Gi) that activates inositol-specific phospholipase C. We have utilized a plasma membrane-containing fraction from unstimulated human neutrophils as the target enzyme to explore the role of G proteins in arachidonate and cytosolic cofactor-dependent activation of the NADPH-dependent O-2-generating oxidase. When certain guanine nucleotides or their nonhydrolyzable analogues were present during arachidonate and cytosolic cofactor-dependent activation, they exerted substantial dose-dependent effects. The GTP analogue, GTP gamma S, caused a 2-fold increase in NADPH oxidase activation (half-maximal stimulation, 1.1 microM). Either GDP or its nonhydrolyzable analogue, GDP beta S, inhibited up to 80% of the basal NADPH oxidase activation (Ki GDP = 0.12 mM, GDP beta S = 0.23 mM). GTP caused only slight and variable stimulation, whereas F-, an agent known to promote the active conformation of G proteins, caused a 1.6-fold stimulation of NADPH oxidase activation. NADPH oxidase activation in the cell-free system was absolutely and specifically dependent on Mg2+. Although O2- production in response to fMet-Leu-Phe was inhibited greater than 90% in neutrophils pretreated with pertussis toxin, cytosolic cofactor and target oxidase membranes from neutrophils treated with pertussis toxin showed no change in basal- or GTP gamma S-stimulated NADPH oxidase activation. Cholera toxin treatment of neutrophils also had no effect on the cell-free activation system. Our results suggest a role for a G protein that is distinct from Gs or Gi in the arachidonate and cytosolic cofactor-dependent NADPH oxidase cell-free activation system.
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PMID:Regulation of neutrophil NADPH oxidase activation in a cell-free system by guanine nucleotides and fluoride. Evidence for participation of a pertussis and cholera toxin-insensitive G protein. 302 97

Inositol trisphosphate (InsP3) production and cytosolic free Ca2+ ([Ca2+]i) elevations induced by leukotriene B4 (LTB4)-receptor activation were studied in the human promyelocytic-leukaemia cell line HL60, induced to differentiate by retinoic acid. The myeloid-differentiated HL60 cells respond to LTB4 by raising their [Ca2+]i with a dose-response relationship similar to that shown by normal human neutrophils. The observations of the LTB4 transduction mechanism were compared with those of the transduction mechanism of the chemotactic peptide fMet-Leu-Phe in HL60 cells differentiated with dimethyl sulphoxide. Both LTB4 and fMet-Leu-Phe triggered a rapid (less than 5 s) elevation of [Ca2+]i, which occurred in parallel with the InsP3 production from myo-[3H]inositol-labelled cells. The threshold concentrations of the agonists, for InsP3 production, were found at 10(-9) M, a slightly higher concentration than that required to detect [Ca2+]i elevations. No significant changes were noted in the phosphoinositide levels upon stimulation with LTB4. Exposure to Bordetella pertussis toxin before LTB4 stimulation abolished both the increased formation of InsP3 and the rise of [Ca2+]i. LTB4 and fMet-Leu-Phe elicited elevations of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] with no detectable lag time, followed by slower and more sustained inositol 1,3,4-trisphosphate elevations. Stimulation with various leukotriene analogues revealed a good correlation between both total InsP3 as well as Ins(1,4,5)P3 formation and elevations of [Ca2+]1. Thus LTB4 receptor activation results in an increased production of Ins(1,4,5)P3 via a transduction mechanism also involving a nucleotide regulatory protein, as previously described for the fMet-Leu-Phe transduction mechanism.
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PMID:Leukotriene B4 stimulation of phagocytes results in the formation of inositol 1,4,5-trisphosphate. A second messenger for Ca2+ mobilization. 302 73

The addition of the chemotactic factor fMet-Leu-Phe to cell homogenates causes a decrease in the pertussis toxin catalyzed ADP-ribosylation of a 41 kDa protein. The fMet-Leu-Phe induced decrease is not abolished in homogenates prepared from phorbol 12-myristate 13-acetate treated neutrophils. This decreased ribosylation probably reflects a dissociation of the GTP-binding protein oligomer that is not followed by association, possibly because of the release of the alpha-subunit into the suspending medium. Furthermore, fMet-Leu-Phe stimulates the binding of radiolabelled guanylylimidodiphosphate to membrane preparations. Again, the stimulated binding of guanylylimidodiphosphate is not affected by treating the intact neutrophils with phorbol 12-myristate 13-acetate. In addition leukotriene B4, platelet activating factor and fMet-Leu-Phe activate a high-affinity GTPase in membrane preparations. The basal level of this GTPase activity is dramatically inhibited in membrane preparations isolated from cells treated with phorbol 12-myristate 13-acetate. On the other hand, the fMet-Leu-Phe stimulated component is only marginally reduced. The present findings suggest that PMA does not prevent receptor G-protein interaction.
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PMID:G-protein dissociation, GTP-GDP exchange and GTPase activity in control and PMA treated neutrophils stimulated by fMet-Leu-Phe. 303 70

Polymorphonuclear leukocytes (PMNs) activate phospholipase C via a guanine nucleotide regulatory (G) protein. Pretreatment of the PMNs with pertussis toxin (PT) or 4-beta-phorbol 12-myristate 13-acetate (PMA) inhibited chemoattractant-induced inositol trisphosphate generation. To determine the loci of inhibition by PT and PMA, G protein-mediated reactions in PMN plasma membranes were examined. Plasma membranes prepared from untreated and PMA-treated PMNs demonstrated equivalent ability of a GTP analogue to suppress high affinity binding of the chemoattractant-N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) to its receptor. The rate, but not the extent, of high affinity binding of GTP gamma[35S] to untreated PMN membranes was stimulated up to 2-fold by preincubation with 1 microM fMet-Leu-Phe. The ability of fMet-Leu-Phe to stimulate the rate of GTP gamma S binding was absent in membranes prepared from PT-treated PMNs, but remained intact in membranes from PMA-treated cells. Hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) via phospholipase C could be activated in untreated PMN membranes by either fMet-Leu-Phe plus GTP or GTP gamma S alone at low concentrations of Ca2+ (0.1-1 microM). Membranes prepared from PT-treated PMNs degraded PIP2 upon exposure to GTP gamma S, but not fMet-Leu-Phe plus GTP. In contrast, membranes prepared from phorbol ester-treated PMNs did not hydrolyze PIP2 when incubated with GTP gamma S. Treatment with PT or PMA did not affect the ability of 1 mM Ca2+ to activate PIP2 hydrolysis in PMN membranes, indicating that neither treatment directly inactivated phospholipase C. Therefore, PT appears to block coupling of the chemoattractant receptors to G protein activation, while phorbol esters disrupt coupling of the activated G protein to phospholipase C. The phorbol ester-mediated effect may mimic a negative feedback signal induced by protein kinase C activation by diacylglycerol generated upon activation of phospholipase C.
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PMID:Nucleotide regulatory protein-mediated activation of phospholipase C in human polymorphonuclear leukocytes is disrupted by phorbol esters. 303 56

The addition of fMet-Leu-Phe, platelet-activating factor, leukotriene B4 or sodium propionate to rabbit neutrophils causes an increase in the amount of actin associated with the cytoskeletal actin. The increase is rapid, transient and inhibitable by pertussis toxin. On the other hand, the addition of phorbol 12-myristate 13-acetate or NH4Cl causes a pertussis toxin-insensitive increase in cytoskeletal actin. The effects of the phorbol ester and fMet-Leu-Phe are additive, and in the presence of the phorbol ester, the fMet-Leu-Phe induced effect declines to the level produced by the phorbol ester. These results suggest that: one of the signalling pathways for actin polymerization involves a guanine-nucleotide binding protein; actin polymerization mediated through this pathway is rapid, transient and inhibitable by pertussis toxin, and a second signalling pathway is independent of this guanine-nucleotide binding protein; actin polymerization, mediated by this second pathway, is somewhat slower, sustained and insensitive to pertussis toxin. These results are discussed in terms of a model which includes gelsolin, profilin and the pertussis toxin-sensitive guanine-nucleotide binding protein.
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PMID:Signalling for increased cytoskeletal actin in neutrophils. 303 46

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