title: Emergence of Orai3 activity during cardiac hypertrophy.
abstract: OBJECTIVE
  Stromal interaction molecule 1 (STIM1) has been shown to control a calcium (Ca(2+)) influx pathway that emerges during the hypertrophic remodelling of cardiomyocytes. Our aim was to determine the interaction of Orai1 and Orai3 with STIM1 and their role in the constitutive store-independent and the store-operated, STIM1-dependent, Ca(2+) influx in cardiomyocytes.
  
  
  RESULTS
  We characterized the expression profile of Orai proteins and their interaction with STIM1 in both normal and hypertrophied adult rat ventricular cardiomyocytes. Orai1 and 3 protein levels were unaltered during the hypertrophic process and both proteins co-immunoprecipitated with STIM1. The level of STIM1 and Orai1 were significantly greater in the macromolecular complex precipitated by the Orai3 antibody in hypertrophied cardiomyocytes. We then used a non-viral method to deliver Cy3-tagged siRNAs in vivo to adult ventricular cardiomyocytes and silence Orai channel candidates. Cardiomyocytes were subsequently isolated then the voltage-independent, i.e. store-independent and store-operated Ca(2+) entries were measured on Fura-2 AM loaded Cy3-labelled and control isolated cardiomyocytes. The whole cell patch-clamp technique was used to measure Orai-mediated currents. Specific Orai1 and Orai3 knockdown established Orai3, but not Orai1, as the critical partner of STIM1 carrying these voltage-independent Ca(2+) entries in the adult hypertrophied cardiomyocytes. Orai3 also drove an arachidonic acid-activated inward current.
  
  
  CONCLUSIONS
  Cardiac Orai3 is the essential partner of STIM1 and drives voltage-independent Ca(2+) entries in adult cardiomyocytes. Arachidonic acid-activated currents, which are supported by Orai3, are present in adult cardiomyocytes and increased during hypertrophy.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France Laboratoire de Recherche en Physiologie et Physiopathologie, Pôle Technologie Santé, Faculté de Médecine, Université Saint Joseph, Beyrouth, Lebanon.
authors.forename: Youakim
authors.initials: Y
authors.lastname: Saliba
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Keck
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Marchand
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Atassi
authors.affiliation: Université Montpellier 1 et 2, Inserm U1046, Montpellier, France.
authors.forename: Aude
authors.initials: A
authors.lastname: Ouillé
authors.affiliation: Université Montpellier 1 et 2, Inserm U1046, Montpellier, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Cazorla
authors.affiliation: SUNY College of Nanoscale Science and Engineering, Albany, NY, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Trebak
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Pavoine
authors.affiliation: Université Montpellier 1 et 2, Inserm U1046, Montpellier, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Lacampagne
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Hulot
authors.affiliation: Laboratoire de Recherche en Physiologie et Physiopathologie, Pôle Technologie Santé, Faculté de Médecine, Université Saint Joseph, Beyrouth, Lebanon.
authors.forename: Nassim
authors.initials: N
authors.lastname: Farès
authors.affiliation: Université Montpellier 1 et 2, Inserm U1046, Montpellier, France.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Fauconnier
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France anne-marie.lompre@upmc.fr.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Lompré
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D002478:Cells, Cultured; D004195:Disease Models, Animal; D017379:Hypertrophy, Left Ventricular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008564:Membrane Potentials; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D000071740:ORAI1 Protein; D011485:Protein Binding; D034622:RNA Interference; D017208:Rats, Wistar; D000071737:Stromal Interaction Molecule 1; D013997:Time Factors; D014162:Transfection
chemical_list: D002120:Calcium Channel Agonists; D015220:Calcium Channels; D008562:Membrane Glycoproteins; D000071740:ORAI1 Protein; C532493:Orai1 protein, rat; C573659:Orai3 protein, rat; C518857:Stim1 protein, rat; D000071737:Stromal Interaction Molecule 1; D016718:Arachidonic Acid
keywords: Calcium; Cardiac hypertrophy; Orai; STIM1; SiRNA