title: Identification of a new dysfunctional platelet P2Y12 receptor variant associated with bleeding diathesis.
abstract: Defects of the platelet P2Y12 receptor (P2Y12R) for adenosine diphosphate (ADP) are associated with increased bleeding risk. The study of molecular abnormalities associated with inherited qualitative defects of the P2Y12R protein is useful to unravel structure-function relationships of the receptor. We describe the case of 2 brothers, sons of first cousins, with lifelong history of abnormal bleeding, associated with dysfunctional P2Y12R and a previously undescribed missense mutation in the encoding gene. ADP (4-20 µM)-induced aggregation of patients' platelets was markedly reduced and rapidly reversible. Other agonists induced borderline-normal aggregation. Inhibition of vasodilator-stimulated phosphoprotein phosphorylation and prostaglandin E1-induced increase in cyclic adenosine monophosphate (cAMP) by ADP was impaired, whereas inhibition of cAMP increase by epinephrine was normal. [(3)H]PSB-0413, a selective P2Y12R antagonist, bound to a normal number of binding sites; however, its affinity, and that of the agonists ADP and 2-methylthio-adenosine-5'-diphosphate, was reduced. Patients' DNA showed a homozygous c.847T>A substitution that changed the codon for His-187 to Gln (p.His187Gln). Crystallographic data and molecular modeling studies indicated that His187 in transmembrane 5 is important for agonist and nucleotide antagonist binding and located in a region undergoing conformational changes. These studies delineate a region of P2Y12R required for normal function after ADP binding.
authors.affiliation: Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda - Ospedale Maggiore Policlinico, Milan, Italy;
authors.forename: Anna
authors.initials: A
authors.lastname: Lecchi
authors.affiliation: Divisione di Medicina 3, Ospedale San Paolo, Dipartimento di Scienze della Salute - Università degli Studi di Milano, Milan, Italy;
authors.forename: Cristina
authors.initials: C
authors.lastname: Razzari
authors.affiliation: Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD;
authors.forename: Silvia
authors.initials: S
authors.lastname: Paoletta
authors.affiliation: Unité Mixte de Recherche_S949, Inserm, Université de Strasbourg, Etablissement Français du Sang-Alsace, Strasbourg, France; and.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Dupuis
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Lea
authors.initials: L
authors.lastname: Nakamura
authors.affiliation: Unité Mixte de Recherche_S949, Inserm, Université de Strasbourg, Etablissement Français du Sang-Alsace, Strasbourg, France; and.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ohlmann
authors.affiliation: Unité Mixte de Recherche_S949, Inserm, Université de Strasbourg, Etablissement Français du Sang-Alsace, Strasbourg, France; and.
authors.forename: Christian
authors.initials: C
authors.lastname: Gachet
authors.affiliation: Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD;
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Jacobson
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Zieger
authors.affiliation: Divisione di Medicina 3, Ospedale San Paolo, Dipartimento di Scienze della Salute - Università degli Studi di Milano, Milan, Italy;
authors.forename: Marco
authors.identifier: http://orcid.org/0000-0002-7343-4534
authors.initials: M
authors.lastname: Cattaneo
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000031:analogs & derivatives / Q000378:metabolism; D001791:Blood Platelet Disorders / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D001792:Blood Platelets / Q000378:metabolism / Q000473:pathology*; D000242:Cyclic AMP / Q000378:metabolism; D006474:Hemorrhagic Disorders / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D062105:Molecular Docking Simulation; D010375:Pedigree; D010974:Platelet Aggregation; D017354:Point Mutation; D058925:Receptors, Purinergic P2Y12 / Q000235:genetics* / Q000378:metabolism; D013872:Thionucleosides / Q000378:metabolism
chemical_list: C511278:PSB-0413; D058925:Receptors, Purinergic P2Y12; D013872:Thionucleosides; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000242:Cyclic AMP