Abstract

Excessive oxidation is widely accepted as a precursor to deleterious cellular function. On the other hand, an awareness of the role of reductive stress as a similar pathological insult is emerging. Here we report early dynamic changes in compartmentalized glutathione (GSH) redox potentials in living cells in response to exogenously supplied thiol-based antioxidants. Noninvasive monitoring of intracellular thiol-disulfide exchange via a genetically encoded biosensor targeted to cytosol and mitochondria revealed unexpectedly rapid oxidation of the mitochondrial matrix in response to GSH ethyl ester or N-acetyl-L-cysteine. Oxidation of the probe occurred within seconds in a concentration-dependent manner and was attenuated with the membrane-permeable ROS scavenger tiron. In contrast, the cytosolic sensor did not respond to similar treatments. Surprisingly, the immediate mitochondrial oxidation was not abrogated by depolarization of mitochondrial membrane potential or inhibition of mitochondrial GSH uptake. After detection of elevated levels of mitochondrial ROS, we systematically inhibited multisubunit protein complexes of the mitochondrial respiratory chain and determined that respiratory complex III is a downstream target of thiol-based compounds. Disabling complex III with myxothiazol completely blocked matrix oxidation induced with GSH ethyl ester or N-acetyl-L-cysteine. Our findings provide new evidence of a functional link between exogenous thiol-containing antioxidants and mitochondrial respiration.

Original languageEnglish (US)
Pages (from-to)C81-C91
JournalAmerican Journal of Physiology - Cell Physiology
Volume309
Issue number2
DOIs
StatePublished - Jul 15 2015

Keywords

  • Antioxidants
  • Glutathione
  • Mitochondria
  • Reductive stress

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

Fingerprint Dive into the research topics of 'Thiol-based antioxidants elicit mitochondrial oxidation via respiratory complex III'. Together they form a unique fingerprint.

  • Cite this