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Cardiovasc Res. 2015 Mar 1;105(3):248-59. doi: 10.1093/cvr/cvu207. Epub 2014 Sep 11.

Emergence of Orai3 activity during cardiac hypertrophy.

Author information

1
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.
2
Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1166, ICAN, F-75005 Paris, France INSERM, UMR_S 1166, ICAN, F-75005 Paris, France.
3
Université Montpellier 1 et 2, Inserm U1046, Montpellier, France.
4
SUNY College of Nanoscale Science and Engineering, Albany, NY, USA.
5
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.
6
Laboratoire de Recherche en Physiologie et Physiopathologie, Pôle Technologie Santé, Faculté de Médecine, Université Saint Joseph, Beyrouth, Lebanon.
7
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.

Abstract

AIMS:

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.

METHODS AND 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.

CONCLUSION:

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.

KEYWORDS:

Calcium; Cardiac hypertrophy; Orai; STIM1; SiRNA

PMID:
25213556
PMCID:
PMC4351368
DOI:
10.1093/cvr/cvu207
[Indexed for MEDLINE]
Free PMC Article

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