Quantitative proteomics using isobaric tags for relative and absolute quantification (iTRAQ™) reveals differential protein expression in sedentary and exercised trained cardiac mitochondria

Abstract

Endurance exercise is known to provide cardioprotection against ischemia‐reperfusion induced myocardial injury, and mitochondrial adaptations may play a critical role in this protection. To investigate exercise‐induced changes in mitochondrial proteins, we compared the proteome of both subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria isolated from hearts of sedentary and exercise trained rats. To achieve this goal, we utilized iTRAQ™, a new method that allows identification and quantification of proteins between multiple samples. Using the Paragon™ algorithm from Protein Pilot™ software, we identified a total of 187 and 173 proteins with 95% confidence in SS and IMF mitochondria, respectively. Out of the 187 proteins identified in SS mitochondria, 25 increased in abundance and 23 decreased (Error Factor (EF) < 2 and p < 0.05) following exercise training. In IMF mitochondria, 27 proteins increased in abundance and 28 proteins decreased after exercise training (EF < 2 and p < 0.05). Importantly, expression of peroxiredoxin‐3 was significantly increased in both SS and IMF mitochondria, and the 10 kDa heat shock protein expression significantly increased in IMF mitochondria following exercise training. We conclude that exercise training induces alterations in the mitochondrial proteome that may contribute to a cardioprotective phenotype. Supported by NIH R01HL067855 (SKP).