scholarly journals Myeloperoxidase-mediated modulation of chemotactic peptide binding to human neutrophils

Blood ◽  
1983 ◽  
Vol 61 (6) ◽  
pp. 1203-1207 ◽  
Author(s):  
TA Lane ◽  
GE Lamkin

Abstract Methionine-containing chemotactic peptides, such as formyl-methionyl- leucyl-phenylalanine (FMLP), are inactivated via a neutrophil-derived, myeloperoxidase-mediated oxidation of the methionine residue. We report that extracellular inactivation of FMLP by myeloperoxidase modulates the apparent binding of methionine-containing chemotactic peptides to their surface receptors. Inhibitors of myeloperoxidase enhanced FMLP binding. At subsaturating concentrations of 3H-FMLP (20 nM), 1 mM cyanide (KCN) increased the binding of 3H-FMLP to human neutrophils (PMN) by 51% +/- 12%. Similar increases occurred with 0.1 mM azide and 10 mM aminotriazole (ATZ). KCN had little effect on maximal 3H-FMLP binding to PMN at saturation (control-17,040 +/- 910 receptors/PMN; KCN- 16,820 +/- 1,940 receptors/PMN), but decreased the concentration of 3H- FMLP required to half-saturate the PMN receptors (control-39 +/- 3 nM; KCN-17 +/- 1 nM). ATZ gave similar results. The binding to PMN of the non-methionine-containing chemotactic peptide 125I-formyl-norleucyl- leucyl-phenylalanyl-norleucyl-tyrosyl-lysine (125I-FNLPNTL) was unaltered by KCN. Also, the binding of 3H-FMLP to myeloperoxidase- deficient PMN was unaltered by KCN. Both KCN and ATZ decreased the oxidation of FMLP by PMN. Finally, ATZ (but not KCN) enhanced the chemotactic migration of PMN in response to submaximal concentrations of FMLP. These studies show that intact PMN inactivate methionine- containing chemotactic peptides by a pathway that is sensitive to myeloperoxidase inhibitors and is absent in myeloperoxidase-deficient PMN. This action results in an apparent decrease in the affinity of the chemotactic peptide receptor for methionine-containing chemotactic peptides, which may modulate chemotatic events in inflammatory loci.

Blood ◽  
1983 ◽  
Vol 61 (6) ◽  
pp. 1203-1207
Author(s):  
TA Lane ◽  
GE Lamkin

Methionine-containing chemotactic peptides, such as formyl-methionyl- leucyl-phenylalanine (FMLP), are inactivated via a neutrophil-derived, myeloperoxidase-mediated oxidation of the methionine residue. We report that extracellular inactivation of FMLP by myeloperoxidase modulates the apparent binding of methionine-containing chemotactic peptides to their surface receptors. Inhibitors of myeloperoxidase enhanced FMLP binding. At subsaturating concentrations of 3H-FMLP (20 nM), 1 mM cyanide (KCN) increased the binding of 3H-FMLP to human neutrophils (PMN) by 51% +/- 12%. Similar increases occurred with 0.1 mM azide and 10 mM aminotriazole (ATZ). KCN had little effect on maximal 3H-FMLP binding to PMN at saturation (control-17,040 +/- 910 receptors/PMN; KCN- 16,820 +/- 1,940 receptors/PMN), but decreased the concentration of 3H- FMLP required to half-saturate the PMN receptors (control-39 +/- 3 nM; KCN-17 +/- 1 nM). ATZ gave similar results. The binding to PMN of the non-methionine-containing chemotactic peptide 125I-formyl-norleucyl- leucyl-phenylalanyl-norleucyl-tyrosyl-lysine (125I-FNLPNTL) was unaltered by KCN. Also, the binding of 3H-FMLP to myeloperoxidase- deficient PMN was unaltered by KCN. Both KCN and ATZ decreased the oxidation of FMLP by PMN. Finally, ATZ (but not KCN) enhanced the chemotactic migration of PMN in response to submaximal concentrations of FMLP. These studies show that intact PMN inactivate methionine- containing chemotactic peptides by a pathway that is sensitive to myeloperoxidase inhibitors and is absent in myeloperoxidase-deficient PMN. This action results in an apparent decrease in the affinity of the chemotactic peptide receptor for methionine-containing chemotactic peptides, which may modulate chemotatic events in inflammatory loci.


1990 ◽  
Vol 111 (6) ◽  
pp. 3077-3086 ◽  
Author(s):  
P J Mansfield ◽  
L A Boxer ◽  
S J Suchard

Polymorphonuclear leukocytes (PMNs) migrate to sites of inflammation or injury in response to chemoattractants released at those sites. The presence of extracellular matrix (ECM) proteins at these sites may influence PMN accumulation at blood vessel walls and enhance their ability to move through tissue. Thrombospondin (TSP), a 450-kD ECM protein whose major proteolytic fragments are a COOH-terminal 140-kD fragment and an NH2-terminal heparin-binding domain (HBD), is secreted by platelets, endothelial cells, and smooth muscle cells. TSP binds specifically to PMN surface receptors and has been shown, in other cell types, to promote directed movement. TSP in solution at low concentrations (30-50 nM) "primed" PMNs for f-Met-Leu-Phe (fMLP)-mediated chemotaxis, increasing the response two- to fourfold. A monoclonal antibody against the HBD of TSP totally abolished this priming effect suggesting that the priming activity resides in the HBD of TSP. Purified HBD retains the priming activity of TSP thereby corroborating the antibody data. TSP alone, in solution at high concentrations (0.5-3.0 microM), stimulated chemotaxis of PMNs and required both the HBD and the 140-kD fragment of TSP. In contrast to TSP in solution, TSP bound to nitrocellulose filters in the range of 20-70 pmol stimulated random locomotion of PMNs. The number of PMNs migrating in response to bound TSP was approximately two orders of magnitude greater than the number of cells that exhibited chemotaxis in response to soluble TSP or fMLP. Monoclonal antibody C6.7, which recognizes an epitope near the carboxyl terminus of TSP, blocked migration stimulated by bound TSP, suggesting that the activity resides in this domain. Using proteolytic fragments, we demonstrated that bound 140-kD fragment, but not HBD, promoted migration of PMNs. Therefore, TSP released at injury sites, alone or in synergy with chemotactic peptides like fMLP, could play a role in directing PMN movement.


1990 ◽  
Vol 267 (3) ◽  
pp. 795-802 ◽  
Author(s):  
R Seifert ◽  
G Schultz ◽  
M Richter-Freund ◽  
J Metzger ◽  
K H Wiesmüller ◽  
...  

Upon exposure to the bacterial chemotactic peptide fMet-Leu-Phe, human neutrophils release lysozyme and generate superoxide anions (O2.-). The synthetic lipoamino acid N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteine (Pam3Cys), which is derived from the N-terminus of bacterial lipoprotein, when attached to Ser-(Lys)4 [giving Pam3Cys-Ser-(Lys)4], activated O2.- formation and lysozyme release in human neutrophils with an effectiveness amounting to about 15% of that of fMet-Leu-Phe. Palmitic acid, muramyl dipeptide, lipopolysaccharide and the lipopeptides Pam3Cys-Ala-Gly, Pam3Cys-Ser-Gly, Pam3Cys-Ser, Pam3Cys-OMe and Pam3Cys-OH did not activate O2.- formation. Pertussis toxin, which ADP-ribosylates guanine-nucleotide-binding proteins (G-proteins) and functionally uncouples formyl peptide receptors from G-proteins, prevented activation of O2.- formation by fMet-Leu-Phe and inhibited Pam3Cys-Ser-(Lys)4-induced O2.- formation by 85%. Lipopeptide-induced exocytosis was pertussis-toxin-insensitive. O2.- formation induced by Pam3Cys-Ser-(Lys)4 and fMet-Leu-Phe was enhanced by cytochalasin B, by a phorbol ester and by a diacylglycerol kinase inhibitor. Addition of activators of adenylate cyclase and removal of extracellular Ca2+ inhibited O2.- formation by fMet-Leu-Phe and Pam3Cys-Ser-(Lys)4 to different extents. Pam3Cys-Ser-(Lys)4 synergistically enhanced fMet-Leu-Phe-induced O2.- formation and primed neutrophils to respond to the chemotactic peptide at non-stimulatory concentrations. Our data suggest the following. (1) Pam3Cys-Ser-(Lys)4 activates neutrophils through G-proteins, involving pertussis-toxin-sensitive and -insensitive processes. (2) The signal transduction pathways activated by fMet-Leu-Phe and Pam3Cys-Ser-(Lys)4 are similar but not identical. (3) In inflammatory processes, bacterial lipoproteins and chemotactic peptides may interact synergistically to activate O2.- formation, leading to enhanced bactericidal activity.


Blood ◽  
1981 ◽  
Vol 58 (1) ◽  
pp. 129-134 ◽  
Author(s):  
D English ◽  
JS Roloff ◽  
JN Lukens

Abstract Human neutrophils exposed to chemotactic concentrations of zymosan- activated serum (ZAS) and a formylated chemotactic peptide (FMLP, 10(- 7)--10(-9) M) were markedly enhanced in their ability to generate superoxide (O2-) upon stimulation with either sodium fluoride or phorbol myristate acetate (PMA). For both fluoride and PMA, enhancement was characterized by a decrease in the lag from stimulation to initiation of superoxide release and by an increase in the rate of superoxide generation--representing faster activation and increased activity of O2- generating enzyme, respectively. Chemotactic concentrations of casein, normal serum, and casein-treated serum enhanced the activity, but not the rate of activation, of the fluoride- stimulated superoxide generating system. This effect on activity was not so impressive as that obtained with FMLP or ZAS. The mechanisms by which FMLP enhanced responsiveness to fluoride and PMA were found to be different. Optimal enhancement for fluoride-stimulated responses required extracellular Ca++. Extracellular glucose, but not extracellular Ca++, was required for enhancement of FMLP of PMA- stimulated responses. A similar glucose requirement could not be demonstrated for chemotactic peptide enhancement of the superoxide- generating system stimulated by fluoride. Fluoride and PMA apparently activate the neutrophil O2- generating enzyme by pathways that are not identical. However, responsiveness of the enzyme to both agents is susceptible to modulation by cellular responses to chemotactic peptides.


1987 ◽  
Vol 88 (3) ◽  
pp. 399-406 ◽  
Author(s):  
F.J. Roos ◽  
A. Zimmermann ◽  
H.U. Keller

The results show that the distinct types of shape produced by phorbol myristate acetate (PMA) and by chemotactic peptides (fNLPNTL) are associated with distinct types of neutrophil movement. Whereas the chemotactic peptide can induce front-tail polarity characterized by an expanding front, a contracted tail and preferential unidirectional movements of intracellular organelles, PMA can only elicit non-polar movements characterized by random formation and retraction of projections all over the surface, intracellular movements of organelles being ill-defined and changing in direction. Combined stimulation of human neutrophils with PMA and fNLPNTL results in a suppression of peptide-induced polarity and the formation of non-polar motile cells resembling those stimulated with PMA alone. The results suggest that the diacylglycerol-protein kinase C pathway may be instrumental in transducing or modulating signals to the locomotor apparatus of the cell. PMA-treated cells are, however, still capable of developing directional responses when appropriately stimulated. The findings lead to the hypothesis that distinct types of neutrophil movements are preferentially associated with distinct functions.


Blood ◽  
1981 ◽  
Vol 58 (1) ◽  
pp. 129-134 ◽  
Author(s):  
D English ◽  
JS Roloff ◽  
JN Lukens

Human neutrophils exposed to chemotactic concentrations of zymosan- activated serum (ZAS) and a formylated chemotactic peptide (FMLP, 10(- 7)--10(-9) M) were markedly enhanced in their ability to generate superoxide (O2-) upon stimulation with either sodium fluoride or phorbol myristate acetate (PMA). For both fluoride and PMA, enhancement was characterized by a decrease in the lag from stimulation to initiation of superoxide release and by an increase in the rate of superoxide generation--representing faster activation and increased activity of O2- generating enzyme, respectively. Chemotactic concentrations of casein, normal serum, and casein-treated serum enhanced the activity, but not the rate of activation, of the fluoride- stimulated superoxide generating system. This effect on activity was not so impressive as that obtained with FMLP or ZAS. The mechanisms by which FMLP enhanced responsiveness to fluoride and PMA were found to be different. Optimal enhancement for fluoride-stimulated responses required extracellular Ca++. Extracellular glucose, but not extracellular Ca++, was required for enhancement of FMLP of PMA- stimulated responses. A similar glucose requirement could not be demonstrated for chemotactic peptide enhancement of the superoxide- generating system stimulated by fluoride. Fluoride and PMA apparently activate the neutrophil O2- generating enzyme by pathways that are not identical. However, responsiveness of the enzyme to both agents is susceptible to modulation by cellular responses to chemotactic peptides.


1986 ◽  
Vol 65 (12) ◽  
pp. 1379-1391 ◽  
Author(s):  
R.J. Genco ◽  
T.E. Van Dyke ◽  
M.J. Levine ◽  
R.D. Nelson ◽  
M.E. Wilson

Major advances in our understanding of the role of the neutrophil in host defense against periodontal organisms have been made through studies of localized juvenile periodontitis (LJP). Several.lines of evidence suggest that LJP is an infectious process closely associated with Actinobacillus (Haemophilus) actinomycetemcomitans as a causative agent, although other organisms may also participate. The immunologic profile of LJP patients suggests that a cell-associated neutrophil locomotory dysfunction is a key underlying immunodeficiency resulting in increased susceptibility to periodontal infection. In addition, LJP patients often exhibit cervical lymphadenopathy and IgG-hypergammaglobulinemia, and a markedly elevated antibody response to the infecting organism, A. actinomycetemcomitans, is found in the serum and crevicular fluid of most patients. Evaluation of the locomotory properties of LJP neutrophils shows that random migration and chemokinesis are normal; however, about 70% of the LJP patients suffer from a defect in chemotaxis, with their neutrophils responding poorly to bacterial chemotaetic factors, synthetic chemotactic peptides, and complement fragments (C5a). Depressed chemotaxis of LJP neutrophils is paralleled by their reduced capacity to bind the synthetic chemotactic peptide N-formylmethionylleucylphenylalanine (FMLP), as well as C5a. Furthermore, there is a reduction in the amount of glycoprotein 110, a neutrophil membrane matrix component and differentiation antigen which is associated with FMLP- and possibly also C5a-mediated chemotaxis. Reduction ofC5a and of FMLP ligand binding, decreased expression of GP-110, and reduced neutrophil chemotaxis are consistent with a stem cell maturation error in LJP patients. This is further supported by studies demonstrating increased expression of CR2, the C3d/EBV receptor, on peripheral blood neutrophils of LJP patients. CR2 receptors are normally present on immature human neutrophils but are lost during the maturation process. These alterations in neutrophil surface components and their reduced chemotaxis may result from a genetically determined abnormality. Studies demonstrating the familial nature of both the neutrophil chemotactic disorder and the clinical entity represented by localized juvenile periodontitis point to a strong role for genetic determinants in the disease which affect neutrophil surface receptors.


Blood ◽  
1992 ◽  
Vol 80 (11) ◽  
pp. 2911-2919 ◽  
Author(s):  
P Kreienbuhl ◽  
H Keller ◽  
V Niggli

Abstract The phosphatase inhibitors okadaic acid and calyculin A were found to elicit or to modify several neutrophil responses, suggesting that dephosphorylation plays a regulatory role. The concentrations of okadaic acid (> or = 1 mumol/L) that were effective on neutrophil functions (shape changes and marginal stimulation of pinocytosis) were shown to stimulate the incorporation of 32PO4 into many neutrophil proteins several-fold. Calyculin A was effective at 50-fold lower concentrations. In the presence of the inhibitors, the cells exhibited a nonpolar shape and the polarization response induced by chemotactic peptide was inhibited. Both phosphatase inhibitors also induced the association of F-actin with the cell membrane. A steady-state phosphatase activity is thus involved in maintaining shape and F-actin localization of resting cells. Inhibitors alone had no significant effect on the amount of cytoskeleton-associated actin. The increase in cytoskeletal actin observed at 30 minutes of stimulation with phorbol ester or 5 to 30 minutes of stimulation with chemotactic peptide, however, was abolished by okadaic acid or calyculin A, suggesting an important role of a phosphatase. In contrast, the early increase in cytoskeleton-associated actin observed at 1 minute of stimulation with peptide was not affected. This finding indicates that the increased association of actin with the cytoskeleton in the early and the later stages of neutrophil activation may be mediated by different signalling pathways.


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