Expression and characterization of a 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid receptor highly expressed on human eosinophils and neutrophils

Mol Pharmacol. 2003 Mar;63(3):471-7. doi: 10.1124/mol.63.3.471.

Abstract

Using a bioinformatics approach, we have isolated a novel G-protein-coupled receptor (GPCR), R527, and have demonstrated that this receptor shows no significant homology to previously deorphanized GPCRs. Quantitative reverse transcription-polymerase chain reaction analysis of the expression of GPCR R527 indicated a very high level of mRNA expression in eosinophils, with high expression also detected in neutrophils and lung macrophages. Stable cell lines were generated expressing this receptor together with the G-protein alpha-subunit G alpha(16). These cells were used to screen an agonist collection in a calcium mobilization assay and 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE) was identified as a putative ligand. 5(S)-hydroxyperoxy-6E,8Z,11Z,14Z-eicosatetraenoic acid was also shown to activate the receptor, whereas the leukotrienes LTB(4), LTC(4), LTD(4), and LTE(4) failed to elicit a response. In cAMP assays, pertussis toxin reversed the inhibitory effects of 5-oxo-ETE on cAMP production, indicating that the receptor is G alpha(i)-coupled. The GPCR R527 shows pharmacological properties similar to those of the previously described 5-oxo-ETE receptor expressed on eosinophils, neutrophils, and monocytes. These cell types show chemotactic responses to 5-oxo-ETE, and this eicosanoid has been proposed to play a key role in the inflammatory response. The molecular identification of a receptor binding 5-oxo-ETE will expand our understanding of the physiological role of this mediator and may provide new therapeutic opportunities.

MeSH terms

  • Amino Acid Sequence
  • Arachidonic Acids / metabolism*
  • Base Sequence
  • Cell Line
  • Cells, Cultured
  • Cloning, Molecular
  • Cyclic AMP / metabolism
  • Eosinophils / metabolism*
  • Gene Expression
  • Humans
  • Ligands
  • Molecular Sequence Data
  • Neutrophils / metabolism*
  • Receptors, Cell Surface / genetics*
  • Receptors, G-Protein-Coupled*
  • Sequence Homology, Amino Acid

Substances

  • Arachidonic Acids
  • G-protein-coupled receptor R527, human
  • Ligands
  • Receptors, Cell Surface
  • Receptors, G-Protein-Coupled
  • 5-oxo-6,8,11,14-eicosatetraenoic acid
  • Cyclic AMP