PURPOSE: Clarify the impact of aerobic interval training (AIT) on cancer-related cardiac dysfunction and cardiac mitochondrial phosphoproteome.
METHODS: Male mice (age=4wk) were exposed to 0.05% N-butyl-N-(4-hydroxybutyl) nitrosamine in the drinking water for 12 weeks (BBN, n=28) or tap water (CONT, n=14). After 12 weeks, half of the animals from each group started AIT (10x4 min at 25 m/min, interspersed by 2 min at 10m/min, 10°, for 8wk, 5 d/wk) (CONT+EX and BBN+EX) while the other half remained sedentary (CONT+SED and BBN+SED). After, animals were prepared for hemodynamic evaluation, sacrificed and heart tissue was collected to isolate mitochondria for TiO2 enrichment followed by LC-MS/MS for phosphoproteome analysis.
RESULTS: Contrarily to BBN+CONT, BBN+EX showed preserved diastolic function, cardiomyocyte hypertrophy, and reduced structural derangement and fibrosis. LC-MS/MS analysis allowed identifying 373 distinct proteins implicated in generation of precursor metabolites and energy, muscle contraction and cellular respiration. BBN mice showed unique proteins related to cardiac tissue morphogenesis whereas the most represented in CONT were involved in cellular respiration and negative regulation of mitochondrial membrane permeability. AIT induced the up-regulation of proteins belonging to cardiac muscle contraction, ATP metabolism and Smad signaling transduction, and lead to the down-regulation of cardiac morphogenesis proteins. We also identified 536 distinct phosphorylated peptides, corresponding to 524 phosphoproteins. Five phosphoproteins were common to all animals, with more phosphoproteins identified in BBN. The biological processes up-regulated by phosphorylation in BBN+CONT were ventricular system development and vasoconstriction while in BBN+EX were cardiac muscle hypertrophy and negative regulation of G-protein coupled receptor protein signaling pathway. PDHK, p38 MAPK and NEK6 were among the predicted kinases activated in cardiac mitochondria from BBN+EX, while GRK1, CAMK4, STKR and NEK2 were in BBN+CONT.
CONCLUSION: AIT protects from cancer-related cardiac dysfunction, which was related to the modulation of cardiac mitochondrial proteome and phosphoproteome.
Funding: EXPL/DTP-DES/1010/2013; FCOMP-01-0124-FEDER-041115, PTDC/DTP-DES/6077/2014.