%0 Journal Article %A Dong Yan %A Rino Stocco %A Nicole Sawyer %A Michael Nesheim %A Mark Abramovitz %A Colin Funk %T Differential Signaling of Cysteinyl Leukotrienes and a Novel Cysteinyl Leukotriene Receptor 2 (CysLT2) Agonist, N-Methyl-Leukotriene C4, in Calcium Reporter and Beta Arrestin Assays %D 2010 %R 10.1124/mol.110.069054 %J Molecular Pharmacology %P mol.110.069054 %X 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 as LTC4 at CysLT2 receptors, but was the least efficacious at CysLT1 receptors. In a β-galactosidase-β-Arrestin complementation assay the hCysLT2 receptor can couple with β-Arrestin-2 and NMLTC4 is slightly more potent for eliciting β-Arrestin-2 binding when compared to cysLTs. Furthermore LTE4 is nearly inactive in this assay compared to 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 while 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 will aid to elucidate its biological roles. %U https://molpharm.aspetjournals.org/content/molpharm/early/2010/11/15/mol.110.069054.full.pdf