title: Palmitoyl-carnitine increases RyR2 oxidation and sarcoplasmic reticulum Ca2+ leak in cardiomyocytes: Role of adenine nucleotide translocase.
abstract: Long chain fatty acids bind to carnitine and form long chain acyl carnitine (LCAC), to enter into the mitochondria. They are oxidized in the mitochondrial matrix. LCAC accumulates rapidly under metabolic disorders, such as acute cardiac ischemia, chronic heart failure or diabetic cardiomyopathy. LCAC accumulation is associated with severe cardiac arrhythmia including ventricular tachycardia or fibrillation. We thus hypothesized that palmitoyl-carnitine (PC), alters mitochondrial function leading to Ca(2+) dependent-arrhythmia. In isolated cardiac mitochondria from C57Bl/6 mice, application of 10μM PC decreased adenine nucleotide translocase (ANT) activity without affecting mitochondrial permeability transition pore (mPTP) opening. Mitochondrial reactive oxygen species (ROS) production, measured with MitoSOX Red dye in isolated ventricular cardiomyocytes, increased significantly under PC application. Inhibition of ANT by bongkrekic acid (20 μM) prevented PC-induced mitochondrial ROS production. In addition, PC increased type 2 ryanodine receptor (RyR2) oxidation, S-nitrosylation and dissociation of FKBP12.6 from RyR2, and therefore increased sarcoplasmic reticulum (SR) Ca(2+) leak. ANT inhibition or anti-oxidant strategy (N-acetylcysteine) prevented SR Ca(2+) leak, FKBP12.6 depletion and RyR2 oxidation/S-nitrosylation induced by PC. Finally, both bongkrekic acid and NAC significantly reduced spontaneous Ca(2+) wave occurrences under PC. Altogether, these results suggest that an elevation of PC disturbs ANT activity and alters Ca(2+) handling in a ROS-dependent pathway, demonstrating a new pathway whereby altered FA metabolism may contribute to the development of ventricular arrhythmia in pathophysiological conditions.
authors.affiliation: INSERM U1046, UMR CNRS 9214, Université de Montpellier, Montpellier, France.
authors.forename: J
authors.initials: J
authors.lastname: Roussel
authors.affiliation: INSERM U1046, UMR CNRS 9214, Université de Montpellier, Montpellier, France.
authors.forename: J
authors.initials: J
authors.lastname: Thireau
authors.affiliation: INSERM UMR-S769 LabEx LERMIT, Université Paris-Sud, Châtenay-Malabry, France.
authors.forename: C
authors.initials: C
authors.lastname: Brenner
authors.affiliation: INSERM U1046, UMR CNRS 9214, Université de Montpellier, Montpellier, France.
authors.forename: N
authors.initials: N
authors.lastname: Saint
authors.affiliation: INSERM U1046, UMR CNRS 9214, Université de Montpellier, Montpellier, France.
authors.forename: V
authors.initials: V
authors.lastname: Scheuermann
authors.affiliation: INSERM U1046, UMR CNRS 9214, Université de Montpellier, Montpellier, France.
authors.forename: A
authors.initials: A
authors.lastname: Lacampagne
authors.affiliation: INSERM U1046, UMR CNRS 9214, Université de Montpellier, Montpellier, France.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Le Guennec
authors.affiliation: INSERM U1046, UMR CNRS 9214, Université de Montpellier, Montpellier, France. Electronic address: jeremy.fauconnier@inserm.fr.
authors.forename: J
authors.initials: J
authors.lastname: Fauconnier
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D001865:Bongkrekic Acid / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D016166:Free Radical Scavengers / Q000494:pharmacology; D015151:Immunoblotting; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D000226:Mitochondrial ADP, ATP Translocases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010172:Palmitoylcarnitine / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism; D022021:Tacrolimus Binding Proteins / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D017382:Reactive Oxygen Species; D019837:Ryanodine Receptor Calcium Release Channel; D001865:Bongkrekic Acid; D010172:Palmitoylcarnitine; D009569:Nitric Oxide; D000226:Mitochondrial ADP, ATP Translocases; D022021:Tacrolimus Binding Proteins; C403484:tacrolimus binding protein 1B; D002118:Calcium; D000111:Acetylcysteine
keywords: ANT; Long chain acyl carnitine; Reactive oxygen species; RyR2