Cutting edge: lipoxins rapidly stimulate nonphlogistic phagocytosis of apoptotic neutrophils by monocyte-derived macrophages

J Immunol. 2000 Feb 15;164(4):1663-7. doi: 10.4049/jimmunol.164.4.1663.

Abstract

Lipoxins (LX) are lipoxygenase-derived eicosanoids generated during inflammation. LX inhibit polymorphonuclear neutrophil (PMN) chemotaxis and adhesion and are putative braking signals for PMN-mediated tissue injury. In this study, we report that LXA4 promotes another important step in the resolution phase of inflammation, namely, phagocytosis of apoptotic PMN by monocyte-derived macrophages (Mphi). LXA4 triggered rapid, concentration-dependent uptake of apoptotic PMN. This bioactivity was shared by stable synthetic LXA4 analogues (picomolar concentrations) but not by other eicosanoids tested. LXA4-triggered phagocytosis did not provoke IL-8 or monocyte chemoattractant protein-1 release. LXA4-induced phagocytosis was attenuated by anti-CD36, alphavbeta3, and CD18 mAbs. LXA4-triggered PMN uptake was inhibited by pertussis toxin and by 8-bromo-cAMP and was mimicked by Rp-cAMP, a protein kinase A inhibitor. LXA4 attenuated PGE2-stimulated protein kinase A activation in Mphi. These results suggest that LXA4 is an endogenous stimulus for PMN clearance during inflammation and provide a novel rationale for using stable synthetic analogues as anti-inflammatory compounds in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology
  • Apoptosis / immunology*
  • Cell Adhesion / immunology
  • Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Dose-Response Relationship, Immunologic
  • Humans
  • Hydroxyeicosatetraenoic Acids / physiology*
  • Lipoxins*
  • Macrophages / immunology*
  • Molecular Mimicry
  • Monocytes / immunology
  • Neutrophils / cytology
  • Neutrophils / enzymology
  • Neutrophils / immunology*
  • Phagocytosis / immunology*

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Hydroxyeicosatetraenoic Acids
  • Lipoxins
  • lipoxin A4
  • Cyclic AMP-Dependent Protein Kinases