Journal
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE
Volume 1852, Issue 5, Pages 749-758Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.bbadis.2015.01.011
Keywords
Long chain acyl carnitine; Reactive oxygen species; ANT; RyR2
Funding
- Groupe de Reflexion sur la Recherche Cardiovasculaire (GRRC)
- ANR Cydiacor
- FRM (Mitochondrial Physiopathology)
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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-camitine (PC), alters mitochondrial function leading to Ca2+ dependent-arrhythmia. In isolated cardiac mitochondria from C57B1/6 mice, application of 10 mu M PC decreased adenine nucleotide translocase (ANT) activity without affecting mitochondria( 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 mu M) 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) Ca2+ leak. ANT inhibition or anti-oxidant strategy (N-acetylcysteine) prevented SR Ca2+ leak, FKBP12.6 depletion and RyR2 oxidation/S-nitrosylation induced by PC. Finally, both bongkrekic acid and NAC significantly reduced spontaneous Ca2+ wave occurrences under PC. Altogether, these results suggest that an elevation of PC disturbs ANT activity and alters Ca2+ 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. (C) 2015 Elsevier B.V. All rights reserved.
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