title: Protamine is an antagonist of apelin receptor, and its activity is reversed by heparin.
abstract: Apelin signaling plays an important role during embryo development and regulates angiogenesis, cardiovascular activity, and energy metabolism in adulthood. Overexpression and hyperactivity of this signaling pathway is observed in various pathologic states, such as cardiovascular diseases and cancer, which highlights the importance of inhibiting apelin receptor (APJ); therefore, we developed a cell-based screening assay that uses fluorescence microscopy to identify APJ antagonists. This approach led us to identify the U.S. Food and Drug Administration-approved compound protamine-already used clinically after cardiac surgery-as an agent to bind to heparin and thereby reverse its anticlotting activity. Protamine displays a 390-nM affinity for APJ and behaves as a full antagonist with regard to G protein and β-arrestin-dependent intracellular signaling.Ex vivoandin vivo, protamine abolishes well-known apelin effects, such as angiogenesis, glucose tolerance, and vasodilatation. Remarkably, protamine antagonist activity is fully reversed by heparin treatment bothin vitroandin vivoThus, our results demonstrate a new pharmacologic property of protamine-blockade of APJ-that could explain some adverse effects observed in protamine-treated patients. Moreover, our data reveal that the established antiangiogenic activity of protamine would rely on APJ antagonism.-Le Gonidec, S., Chaves-Almagro, C., Bai, Y., Kang, H. J., Smith, A., Wanecq, E., Huang, X.-P., Prats, H., Knibiehler, B., Roth, B. L., Barak, L. S., Caron, M. G., Valet, P., Audigier, Y., Masri, B. Protamine is an antagonist of apelin receptor, and its activity is reversed by heparin.
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires, INSERM Unité 1048, Université de Toulouse, Université Paul Sabatier, Toulouse, France.|Service Phénotypage, Centre Régional d'Exploration Fonctionnelle et Ressources Expérimentales, INSERM US006, Université de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Le Gonidec
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires, INSERM Unité 1048, Université de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Carline
authors.initials: C
authors.lastname: Chaves-Almagro
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Pharmacology, University of North Carolina at Chapel Hill Medical School, Chapel Hill, North Carolina, USA.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kang
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Allyson
authors.initials: A
authors.lastname: Smith
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires, INSERM Unité 1048, Université de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Wanecq
authors.affiliation: Department of Pharmacology, University of North Carolina at Chapel Hill Medical School, Chapel Hill, North Carolina, USA.
authors.forename: Xi-Ping
authors.initials: XP
authors.lastname: Huang
authors.affiliation: Centre de Recherches en Cancérologie de Toulouse, Unité Mixte de Recherche 1037 INSERM, Université de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Prats
authors.affiliation: Centre de Recherches en Cancérologie de Toulouse, Unité Mixte de Recherche 1037 INSERM, Université de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Knibiehler
authors.affiliation: Department of Pharmacology, University of North Carolina at Chapel Hill Medical School, Chapel Hill, North Carolina, USA.
authors.forename: Bryan L
authors.initials: BL
authors.lastname: Roth
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Larry S
authors.initials: LS
authors.lastname: Barak
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA.|Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.|Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Marc G
authors.initials: MG
authors.lastname: Caron
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires, INSERM Unité 1048, Université de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Valet
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires, INSERM Unité 1048, Université de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Audigier
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires, INSERM Unité 1048, Université de Toulouse, Université Paul Sabatier, Toulouse, France; bernard.masri@inserm.fr.
authors.forename: Bernard
authors.initials: B
authors.lastname: Masri
mesh_terms: D000818:Animals; D000075244:Apelin Receptors; D045744:Cell Line, Tumor; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D057809:HEK293 Cells; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011479:Protamines / Q000494:pharmacology*; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: C104575:APLNR protein, human; D000075244:Apelin Receptors; C491285:Aplnr protein, mouse; D011479:Protamines; D043562:Receptors, G-Protein-Coupled; D006493:Heparin
keywords: APJ; GPCR; angiogenesis; blood pressure; metabolism