Abstract 445: Characterizing The Cardiac Acetylome During Exercise

Recent advances in mass spectrometry have led to in-depth characterization of both tissue and cellular acetylation profiles (or “acetylomes”). These studies reveal the abundance and importance of this post-translational modification not only in transcriptional control, but also in many signaling and metabolic pathways. In the heart, acetylation has been found to play a role in cardiac proliferation, differentiation, and hypertrophy in both developmental and pathological settings. To examine the role of acetylation in exercise-induced cardiac hypertrophy, we studied the expression of enzymes regulating these processes and then undertook a comprehensive proteomic analysis of cardiac proteome and acetylome in hearts from sedentary and exercised mice. We first characterized the expression profiles of 8 acetylases (MYST1-4, GCN5, PCAF, EP300, CREBBP) and 18 deacetylases (HDAC1-11 and SIRT1-7) in four different exercise protocols, including swimming, voluntary wheel run, acute treadmill run, and long-term treadmill run in aged mice. Then, using a proteomics workflow with greater sensitivity and higher coverage recently developed at the Broad Institute, we determined the acetylome of the swim exercised mouse heart (n=5) in comparison to sedentary animals (n=4). We concurrently assessed proteome and phospho-proteome profiles in the same set of samples. Confirmation of the presence of physiological hypertrophy and increased cardiac function with exercise was determined with echocardiography and morphometric analysis. With this method, we identified 4159 acetylation sites and 19,402 phosphorylation sites on 6615 proteins. Acetylated proteins were found to be involved in a diverse array of processes, but most prominently in metabolism and muscle contraction. Phospho-proteome analysis has highlighted the interplay and crosstalk between acetylation and phosphorylation. In summary, the cardiac acetylome is dynamically regulated by exercise and demonstrates major alterations in metabolic pathways. Understanding how physiological hypertrophy affects acetylation and the activity of downstream factors may provide novel insights into the cardioprotective role of exercise.