Thiol regulation of pro-inflammatory cytokines and innate immunity: protein S-thiolation as a novel molecular mechanism.
ABSTRACT Inflammation or inflammatory cytokines and oxidative stress have often been associated, and thiol antioxidants, particularly glutathione, have often been seen as possible anti-inflammatory mediators. However, whereas several cytokine inhibitors have been approved for drug use in chronic inflammatory diseases, this has not happened with antioxidant molecules. We outline the complexity of the role of protein thiol-disulfide oxidoreduction in the regulation of immunity and inflammation, the underlying molecular mechanisms (such as protein glutathionylation) and the key enzyme players such as Trx (thioredoxin) or Grx (glutaredoxin).
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ABSTRACT: Under physiological conditions, the balance between ROS production and removal maintains properly the intracellular redox-sensitive signaling as well as the appropriate status of protein thiols and disulfides. However, inflammation among other factors can modify this balance causing a rapid increase of intracellular ROS levels and hence thiol oxidation, eventually leading to oxidative stress. In the case of acute pancreatitis, both redox signaling and oxidative stress seem to contribute to the progression of the severe form of the disease. In this review we will focus in the reversible oxidation of protein cysteines during the course of acute pancreatitis. We describe disulfide stress in an acute inflammatory process, which is characterized by thiol oxidation in proteins, particularly protein cysteinylation, without significant changes in the glutathione redox status.Inflammation & Allergy - Drug Targets (Formerly ?Current Drug Targets - Inflammation & Allergy) 12/2014; 13(5).
Dataset: 28.Moreno ML et al FRBM 2014
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ABSTRACT: Bottom-up mass spectrometry studies typically employ a reduction and alkylation step that eliminates a class of post-translational modification, S-thiolation. Given that molecular oxygen can mediate S-thiolation from reduced thiols, which are abundant in the reducing intracellular milieu, we investigated the possibility that some S-thiolation modifications are artifacts of protein preparation. SOD1 was chosen for this case study as it has a reactive surface cysteine residue, which is readily cysteinylated in vitro. The ability of oxygen to generate S-thiolation artifacts was tested by comparing purification of SOD1 from post-mortem human cerebral cortex under aerobic and anaerobic conditions. S-thiolation was ∼50% higher in aerobically processed preparations, consistent with oxygen-dependent artifactual S-thiolation. The ability of endogenous small molecule disulfides (e.g. cystine) to participate in artifactual S-thiolation was tested by blocking reactive protein cysteine residues during anaerobic homogenization. A 50-fold reduction in S-thiolation occurred, indicating the majority of S-thiolation observed aerobically was artifact. Tissue-specific artifacts were explored by comparing brain- and blood-derived protein, with remarkably more artifacts observed in brain-derived SOD1. Given the potential for such artifacts, rules-of-thumb for sample preparation are provided. This study demonstrates that without taking extraordinary precaution, artifactual S-thiolation of highly reactive, surface exposed, cysteine residues can result. This article is protected by copyright. All rights reservedProteomics 03/2014; · 3.97 Impact Factor