title: Induction of novel agonist selectivity for the ADP-activated P2Y1 receptor versus the ADP-activated P2Y12 and P2Y13 receptors by conformational constraint of an ADP analog.
abstract: ADP is the cognate agonist of the P2Y1, P2Y12, and P2Y13 receptors. With the goal of identifying a high potency agonist that selectively activates the P2Y1 receptor, we examined the pharmacological selectivity of the conformationally constrained non-nucleotide analog (N)-methanocarba-2MeSADP [(1'S,2'R, 3'S,4'R,5'S)-4-[(6-amino-2-methylthio-9H-purin-9-yl)-1-diphosphoryloxymethyl]bicyclo[3.1.0]hexane-2,3-diol] among the three ADP-activated receptors. Each P2Y receptor was expressed transiently in COS-7 cells, and inositol lipid hydrolysis was quantified as a measure of receptor activity. In the case of the Gi-linked P2Y12 and P2Y13 receptors, a chimeric G protein, Galphaq/i, was coexpressed to confer a capacity of these Gi-linked receptors to activate phospholipase C. 2MeSADP (2-methylthio-ADP) was a potent agonist at all three receptors exhibiting EC50 values in the sub to low nanomolar range. In contrast, whereas (N)-methanocarba-2MeSADP was an extremely potent (EC50=1.2 +/- 0.2 nM) agonist at the P2Y1 receptor, this non-nucleotide analog exhibited no agonist activity at the P2Y12 receptor and very low activity at the P2Y13 receptor. (N)-Methanocarba-2MeSADP also failed to block the action of 2MeSADP at the P2Y12 and P2Y13 receptors, indicating that the (N)-methanocarba analog is not an antagonist at these receptors. The P2Y1 receptor selectivity of (N)-methanocarba-2MeSADP was confirmed in human platelets where it induced the shape change promoted by P2Y1 receptor activation without inducing the sustained platelet aggregation that requires simultaneous activation of the P2Y12 receptor. These results provide the first demonstration of a high-affinity agonist that discriminates among the three ADP-activated P2Y receptors, and therefore, introduce a potentially important new pharmacological tool for delineation of the relative biological action of these three signaling proteins.
authors.affiliation: University of North Carolina, School of Medicine, Department of Pharmacology, CB #7365, Chapel Hill, NC 27599-7365, USA.
authors.forename: Mariya
authors.initials: M
authors.lastname: Chhatriwala
authors.forename: R Gnana
authors.initials: RG
authors.lastname: Ravi
authors.forename: Roshni I
authors.initials: RI
authors.lastname: Patel
authors.forename: Jose L
authors.initials: JL
authors.lastname: Boyer
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Jacobson
authors.forename: T Kendall
authors.initials: TK
authors.lastname: Harden
mesh_terms: D000244:Adenosine Diphosphate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D015195:Drug Design; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000235:genetics; D008968:Molecular Conformation; D058910:Purinergic P2 Receptor Agonists; D058919:Purinergic P2 Receptor Antagonists; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects; D018048:Receptors, Purinergic P2 / Q000235:genetics; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12; D013329:Structure-Activity Relationship; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; C546382:P2RY1 protein, human; C548576:P2RY12 protein, human; C440036:P2RY13 protein, human; D058910:Purinergic P2 Receptor Agonists; D058919:Purinergic P2 Receptor Antagonists; D043562:Receptors, G-Protein-Coupled; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12; D000244:Adenosine Diphosphate; D010738:Type C Phospholipases