RT Journal Article
SR Electronic
T1 Differential Signaling of Cysteinyl Leukotrienes and a Novel Cysteinyl Leukotriene Receptor 2 (CysLT<sub>2</sub>) Agonist, <em>N</em>-Methyl-Leukotriene C<sub>4</sub>, in Calcium Reporter and β Arrestin Assays
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 270
OP 278
DO 10.1124/mol.110.069054
VO 79
IS 2
A1 Dong Yan
A1 Rino Stocco
A1 Nicole Sawyer
A1 Michael E. Nesheim
A1 Mark Abramovitz
A1 Colin D. Funk
YR 2011
UL http://molpharm.aspetjournals.org/content/79/2/270.abstract
AB The cysteinyl leukotrienes (cysLTs) LTC4, LTD4, and LTE4 are lipid mediators with physiological and pathophysiological functions. They exert their effects through G protein-coupled receptors (GPCRs), most notably via CysLT1 and CysLT2 receptor. The roles of the CysLT2 receptor are beginning to emerge. Both LTC4 and LTD4 are potent agonists for the CysLT2 receptor; however, LTC4 is rapidly converted to LTD4, which is also the main endogenous ligand for the CysLT1 receptor. A selective and potent agonist at the CysLT2 receptor would facilitate studies to discern between receptor subtypes. We show here that N-methyl LTC4 (NMLTC4), a metabolically stable LTC4 mimetic, is a potent and selective CysLT2 receptor agonist. Two expression systems were used to evaluate the functional activity of NMLTC4 at human and/or mouse CysLT1 and CysLT2 receptors. Through the aequorin cell-based assay for calcium-coupled GPCRs, NMLTC4 was almost equipotent to LTC4 at CysLT2 receptors but was the least efficacious at CysLT1 receptors. In a β-galactosidase–β-arrestin complementation assay, the human (h) CysLT2 receptor can couple with β-arrestin-2, and NMLTC4 is slightly more potent for eliciting β-arrestin-2 binding compared with cysLTs. Furthermore, LTE4 is nearly inactive in this assay compared with its weak partial agonist activity in the aequorin system. In a vascular leakage assay, NMLTC4 is potent and active in mice overexpressing hCysLT2 receptor in endothelium, whereas the response is abrogated in CysLT2 receptor knockout mice. Therefore, NMLTC4 is a potent subtype selective agonist for the CysLT2 receptor in vitro and in vivo, and it will be useful to elucidate its biological roles.