Activation of the integrated stress response rewires cardiac metabolism in Barth syndrome

Ilona Kutschka, Edoardo Bertero, Christina Wasmus, Ke Xiao, Lifeng Yang, Xinyu Chen, Yasuhiro Oshima, Marcus Fischer, Manuela Erk, Berkan Arslan, Lin Alhasan, Daria Grosser, Katharina J. Ermer, Alexander Nickel, Michael Kohlhaas, Hanna Eberl, Sabine Rebs, Katrin Streckfuss-Bömeke, Werner Schmitz, Peter RehlingThomas Thum, Takahiro Higuchi, Joshua Rabinowitz, Christoph Maack, Jan Dudek

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Barth Syndrome (BTHS) is an inherited cardiomyopathy caused by defects in the mitochondrial transacylase TAFAZZIN (Taz), required for the synthesis of the phospholipid cardiolipin. BTHS is characterized by heart failure, increased propensity for arrhythmias and a blunted inotropic reserve. Defects in Ca2+-induced Krebs cycle activation contribute to these functional defects, but despite oxidation of pyridine nucleotides, no oxidative stress developed in the heart. Here, we investigated how retrograde signaling pathways orchestrate metabolic rewiring to compensate for mitochondrial defects. In mice with an inducible knockdown (KD) of TAFAZZIN, and in induced pluripotent stem cell-derived cardiac myocytes, mitochondrial uptake and oxidation of fatty acids was strongly decreased, while glucose uptake was increased. Unbiased transcriptomic analyses revealed that the activation of the eIF2α/ATF4 axis of the integrated stress response upregulates one-carbon metabolism, which diverts glycolytic intermediates towards the biosynthesis of serine and fuels the biosynthesis of glutathione. In addition, strong upregulation of the glutamate/cystine antiporter xCT increases cardiac cystine import required for glutathione synthesis. Increased glutamate uptake facilitates anaplerotic replenishment of the Krebs cycle, sustaining energy production and antioxidative pathways. These data indicate that ATF4-driven rewiring of metabolism compensates for defects in mitochondrial uptake of fatty acids to sustain energy production and antioxidation.

Original languageEnglish (US)
Article number47
JournalBasic Research in Cardiology
Volume118
Issue number1
DOIs
StatePublished - Dec 2023

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Keywords

  • Amino acid
  • Barth syndrome
  • Fatty acid oxidation
  • Metabolism
  • Mitochondria
  • Oxidative stress

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