Receptor Binding Kinetics and Cellular Responses of Six N-Formyl Peptide Agonists in Human Neutrophils†

Biochemistry ◽  
2004 ◽  
Vol 43 (25) ◽  
pp. 8204-8216 ◽  
Author(s):  
Anna Waller ◽  
Karyn L. Sutton ◽  
Tamara L. Kinzer-Ursem ◽  
Afaf Absood ◽  
John R. Traynor ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Cellular Responses ◽  
Binding Kinetics ◽  
Human Neutrophils ◽  
Formyl Peptide

Actin Polymerization, Calcium-Transients, and Phospholipid Metabolism in Human Neutrophils After Stimulation with Interleukin-8 and N-formyl Peptide

1994 ◽  
Vol 102 (3) ◽  
pp. 310-314 ◽  
Author(s):  
Johannes Norgauer ◽  
Jean Krutmann ◽  
Gustav J. Dobos ◽  
Alexis E. Traynor-Kaplan ◽  
Zenaida G. Oades ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Phospholipid Metabolism ◽  
Interleukin 8 ◽  
Calcium Transients ◽  
Human Neutrophils ◽  
Formyl Peptide

scholarly journals Chemical Composition and Immunomodulatory Activity of Essential Oils from Rhododendron albiflorum

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3652
Author(s):  
Igor A. Schepetkin ◽  
Gulmira Özek ◽  
Temel Özek ◽  
Liliya N. Kirpotina ◽  
Andrei I. Khlebnikov ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Essential Oils ◽  
Neutrophil Migration ◽  
Compositional Analysis ◽  
Microglial Cells ◽  
Formyl Peptide Receptor ◽  
Human Neutrophils ◽  
Immunomodulatory Activity ◽  
Hl60 Cells ◽  
Formyl Peptide

Rhododendron (Ericaceae) extracts contain flavonoids, chromones, terpenoids, steroids, and essential oils and are used in traditional ethnobotanical medicine. However, little is known about the immunomodulatory activity of essential oils isolated from these plants. Thus, we isolated essential oils from the flowers and leaves of R. albiflorum (cascade azalea) and analyzed their chemical composition and innate immunomodulatory activity. Compositional analysis of flower (REOFl) versus leaf (REOLv) essential oils revealed significant differences. REOFl was comprised mainly of monoterpenes (92%), whereas sesquiterpenes were found in relatively low amounts. In contrast, REOLv was primarily composed of sesquiterpenes (90.9%), with a small number of monoterpenes. REOLv and its primary sesquiterpenes (viridiflorol, spathulenol, curzerene, and germacrone) induced intracellular Ca2+ mobilization in human neutrophils, C20 microglial cells, and HL60 cells transfected with N-formyl peptide receptor 1 (FPR1) or FPR2. On the other hand, pretreatment with these essential oils or component compounds inhibited agonist-induced Ca2+ mobilization and chemotaxis in human neutrophils and agonist-induced Ca2+ mobilization in microglial cells and FPR-transfected HL60 cells, indicating that the direct effect of these compounds on [Ca2+]i desensitized the cells to subsequent agonist activation. Reverse pharmacophore mapping suggested several potential kinase targets for these compounds; however, these targets were not supported by kinase binding assays. Our results provide a cellular and molecular basis to explain at least part of the beneficial immunotherapeutic properties of the R. albiflorum essential oils and suggest that essential oils from leaves of this plant may be effective in modulating some innate immune responses, possibly by inhibition of neutrophil migration.

scholarly journals Salmonella typhimurium attachment to human intestinal epithelial monolayers: transcellular signalling to subepithelial neutrophils.

1993 ◽  
Vol 123 (4) ◽  
pp. 895-907 ◽  
Author(s):  
B A McCormick ◽  
S P Colgan ◽  
C Delp-Archer ◽  
S I Miller ◽  
J L Madara
Keyword(s):  
Epithelial Cells ◽  
Salmonella Typhimurium ◽  
Apical Membrane ◽  
Coli Strain ◽  
Formyl Peptide Receptor ◽  
Human Neutrophils ◽  
Classical Pathway ◽  
Intestinal Epithelial ◽  
Formyl Peptide

In human intestinal disease induced by Salmonella typhimurium, transepithelial migration of neutrophils (PMN) rapidly follows attachment of the bacteria to the epithelial apical membrane. In this report, we model those interactions in vitro, using polarized monolayers of the human intestinal epithelial cell, T84, isolated human PMN, and S. typhimurium. We show that Salmonella attachment to T84 cell apical membranes did not alter monolayer integrity as assessed by transepithelial resistance and measurements of ion transport. However, when human neutrophils were subsequently placed on the basolateral surface of monolayers apically colonized by Salmonella, physiologically directed transepithelial PMN migration ensued. In contrast, attachment of a non-pathogenic Escherichia coli strain to the apical membrane of epithelial cells at comparable densities failed to stimulate a directed PMN transepithelial migration. Use of the n-formyl-peptide receptor antagonist N-t-BOC-1-methionyl-1-leucyl-1- phenylalanine (tBOC-MLP) indicated that the Salmonella-induced PMN transepithelial migration response was not attributable to the classical pathway by which bacteria induce directed migration of PMN. Moreover, the PMN transmigration response required Salmonella adhesion to the epithelial apical membrane and subsequent reciprocal protein synthesis in both bacteria and epithelial cells. Among the events stimulated by this interaction was the epithelial synthesis and polarized release of the potent PMN chemotactic peptide interleukin-8 (IL-8). However, IL-8 neutralization, transfer, and induction experiments indicated that this cytokine was not responsible for the elicited PMN transmigration. These data indicate that a novel transcellular pathway exists in which subepithelial PMN respond to lumenal pathogens across a functionally intact epithelium. Based on the known unique characteristics of the intestinal mucosa, we speculate that IL-8 may act in concert with an as yet unidentified transcellular chemotactic factor(s) (TCF) which directs PMN migration across the intestinal epithelium.

scholarly journals Kinetics of cytokine receptor trafficking determine signaling and functional selectivity

2019 ◽  
Author(s):  
J. Martinez-Fabregas ◽  
S. Wilmes ◽  
L. Wang ◽  
M. Hafer ◽  
E. Pohler ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Ex Vivo ◽  
Treg Cells ◽  
Cytokine Receptor ◽  
Binding Kinetics ◽  
Functional Selectivity ◽  
Gene Expression Response ◽  
Surface Receptors ◽  
Downstream Signaling ◽  
Stat3 Phosphorylation

ABSTRACTCytokines activate downstream signaling networks via assembly of cell surface receptors, but it is unclear whether modulation of cytokine-receptor binding parameters can modify biological outcomes. We have engineered variants of IL-6 with different affinities to the gp130 receptor chain to investigate how cytokine receptor binding kinetics influence functional selectivity. Engineered IL-6 variants showed a range of signaling amplitudes, from minimal to full agonist, and induced biased signaling, with changes in receptor binding kinetics affecting more profoundly STAT1 than STAT3 phosphorylation. We show that this differential signaling arises from defective translocation of ligand-gp130 complexes to the endosomal compartment and competitive STAT1/STAT3 binding to phospho-tyrosines in gp130, and results in unique patterns of STAT3 binding to chromatin. This, in turn, leads to a graded gene expression response and substantial differences in ex vivo differentiation of Th17, Th1 and Treg cells. These results provide a molecular understanding of signaling biased by cytokine receptors, and demonstrate that manipulation of signaling thresholds is a useful strategy to decouple cytokine functional pleiotropy.

Flow cytometry reveals different lag times in rapid cytoplasmic calcium elevations in human neutrophils in response to N-formyl peptide

1993 ◽  
Vol 157 (3) ◽  
pp. 637-643 ◽  
Author(s):  
Jörn Elsner ◽  
Johannes Norgauer ◽  
Gustav J. Dobos ◽  
Andreas Emmendörffer ◽  
Erwin Schöpf ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Human Neutrophils ◽  
Cytoplasmic Calcium ◽  
Formyl Peptide ◽  
Lag Times

Glycosylation of Erythropoietin Affects Receptor Binding Kinetics:  Role of Electrostatic Interactions

Biochemistry ◽  
2002 ◽  
Vol 41 (49) ◽  
pp. 14524-14531 ◽  
Author(s):  
Ryan J. Darling ◽  
Uma Kuchibhotla ◽  
Wolfgang Glaesner ◽  
Radmila Micanovic ◽  
Derrick R. Witcher ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Electrostatic Interactions ◽  
Binding Kinetics

scholarly journals Influence of botulinum C2 toxin on F-actin and N-formyl peptide receptor dynamics in human neutrophils.

1989 ◽  
Vol 109 (3) ◽  
pp. 1133-1140 ◽  
Author(s):  
J Norgauer ◽  
I Just ◽  
K Aktories ◽  
L A Sklar
Keyword(s):  
Actin Polymerization ◽  
Response Characteristic ◽  
Formyl Peptide Receptor ◽  
Human Neutrophils ◽  
Peptide Ligand ◽  
Light Scatter ◽  
Binding Studies ◽  
Rhodamine Phalloidin ◽  
Formyl Peptide ◽  
C2 Toxin

Stimulation of human neutrophils with the chemotactic N-formyl peptide causes production of oxygen radicals and conversion of monomeric actin (G-actin) to polymeric actin (F-actin). The effects of the binary botulinum C2 toxin on the amount of F-actin and on neutrophil cell responses were studied. Two different methods for analyzing the actin response were used in formyl peptide-stimulated cells: staining of F-actin with rhodamine-phalloidin and a transient right angle light scatter. Preincubation of neutrophils with 400 ng/ml component I and 1,600 ng/ml component II of botulinum C2 toxin for 30 min almost completely inhibited the formyl peptide-stimulated polymerization of G-actin and at the same time decreased the amount of F-actin in unstimulated neutrophils by an average of approximately 30%. Botulinum C2 toxin preincubation for 60 min destroyed approximately 75% of the F-actin in unstimulated neutrophils. Right angle light scatter analysis showed that control neutrophils exhibited the transient response characteristic of actin polymerization; however, after botulinum C2 toxin treatment, degranulation was detected. Single components of the binary botulinum C2 toxin were without effect on the actin polymerization response. Fluorescence flow cytometry and fluorospectrometric binding studies showed little alteration in N-formyl peptide binding or dissociation dynamics in the toxin-treated cells. However, endocytosis of the fluorescent N-formyl peptide ligand-receptor complex was slower but still possible in degranulating neutrophils treated with botulinum C2 toxin for 60 min. The half-time of endocytosis, estimated from initial rates, was 4 and 8 min in control and botulinum C2 toxin-treated neutrophils, respectively.

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