Expression and Characterization of a 5-oxo-6E,8Z,11Z,14Z-Eicosatetraenoic Acid Receptor Highly Expressed on Human Eosinophils and Neutrophils

• Published in: Molecular pharmacology 2003-03, Vol.63 (3), p.471-477
• Main Authors: Jones, Carol E, Holden, Suzanne, Tenaillon, Laurent, Bhatia, Umesh, Seuwen, Klaus, Tranter, Pamela, Turner, Jonathan, Kettle, Rachel, Bouhelal, Rochdi, Charlton, Steven, Nirmala, N R, Jarai, Gabor, Finan, Peter
• Format: Article
• Language: English
• Subjects: 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
• ISSN: 0026-895X; 1521-0111
• DOI: 10.1124/mol.63.3.471

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 α-subunit Gα 16 . These cells were used to screen an agonist collection in a calcium mobilization assay and 5-oxo-6 E ,8 Z ,11 Z ,14 Z -eicosatetraenoic acid (5-oxo-ETE) was identified as a putative ligand. 5( S )-Hydroxyperoxy-6 E ,8 Z ,11 Z ,14 Z -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 Gα 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.