Reactivation of desensitized formyl peptide receptors by platelet activating factor: a novel receptor cross talk mechanism regulating neutrophil superoxide anion production

PLoS One. 2013;8(3):e60169. doi: 10.1371/journal.pone.0060169. Epub 2013 Mar 28.

Abstract

Neutrophils express different chemoattractant receptors of importance for guiding the cells from the blood stream to sites of inflammation. These receptors communicate with one another, a cross talk manifested as hierarchical, heterologous receptor desensitization. We describe a new receptor cross talk mechanism, by which desensitized formyl peptide receptors (FPRdes) can be reactivated. FPR desensitization is induced through binding of specific FPR agonists and is reached after a short period of active signaling. The mechanism that transfers the receptor to a non-signaling desensitized state is not known, and a signaling pathway has so far not been described, that transfers FPRdes back to an active signaling state. The reactivation signal was generated by PAF stimulation of its receptor (PAFR) and the cross talk was uni-directional. LatrunculinA, an inhibitor of actin polymerization, induced a similar reactivation of FPRdes as PAF while the phosphatase inhibitor CalyculinA inhibited reactivation, suggesting a role for the actin cytoskeleton in receptor desensitization and reactivation. The activated PAFR could, however, reactivate FPRdes also when the cytoskeleton was disrupted prior to activation. The receptor cross talk model presented prophesies that the contact on the inner leaflet of the plasma membrane that blocks signaling between the G-protein and the FPR is not a point of no return; the receptor cross-talk from the PAFRs to the FPRdes initiates an actin-independent signaling pathway that turns desensitized receptors back to a signaling state. This represents a novel mechanism for amplification of neutrophil production of reactive oxygen species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Azepines / pharmacology
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • Calcium / metabolism
  • Cells, Cultured
  • Cyclosporine / pharmacology
  • Cytochalasin B / pharmacology
  • Cytoskeleton / drug effects
  • Cytoskeleton / metabolism
  • Gelsolin / pharmacology
  • Humans
  • Marine Toxins
  • NADPH Oxidases / metabolism
  • Neutrophils / drug effects
  • Neutrophils / enzymology
  • Neutrophils / metabolism*
  • Oligopeptides
  • Oxazoles / pharmacology
  • Peptide Fragments / pharmacology
  • Platelet Activating Factor / pharmacology*
  • Receptors, Formyl Peptide / agonists
  • Receptors, Formyl Peptide / antagonists & inhibitors
  • Receptors, Formyl Peptide / metabolism*
  • Superoxides / metabolism*
  • Thiazolidines / pharmacology
  • Triazoles / pharmacology

Substances

  • Actins
  • Azepines
  • Bridged Bicyclo Compounds, Heterocyclic
  • Gelsolin
  • Marine Toxins
  • Oligopeptides
  • Oxazoles
  • Peptide Fragments
  • Platelet Activating Factor
  • Receptors, Formyl Peptide
  • Thiazolidines
  • Triazoles
  • gelsolin (160-169)
  • WEB 2086
  • Superoxides
  • Cytochalasin B
  • calyculin A
  • Cyclosporine
  • NADPH Oxidases
  • cyclosporin H
  • latrunculin A
  • Calcium

Grants and funding

The work was supported by the Swedish Medical Research Council, the King Gustaf V 80-Year Foundation, the Göteborg Rheumatism Association, and the Swedish state under the ALF-agreement. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.