Abstract Aerobic exercise-induced cardiac hypertrophy is a physiological response involving accurate orchestration of gene and protein expression of contractile and metabolic components. The microRNAs: miR-208a, miR-208b and miR-499 are each encoded by a myosin gene and thus are also known as "MyomiRs", regulating several mRNA targets that in turn regulate cardiac hypertrophy and metabolic pathways. Aims: To understand the role of myomiRs in the fine-tuning of cardiac MHC isoform expression by exercise training-induced physiological hypertrophy. Wistar rats were subjected to two different swim training protocols. Results: We observed that high-volume swim training (T2), improved cardiac diastolic function, induced cardiac hypertrophy and decreased the expression of miR-208a and 208b. Consequently, the increased expression of their targets, Sox6, Med13, PurB, SP3 and HP1B was more prominent in T2, thus converging to modulate cardiac metabolic and contractile adaptation by exercise training, with an improvement in the α/β-MHC ratio, bypassing the increase in PPARβ and HDAC class I and II regulation. Conclusions: Altogether, we conclude that high-volume swim training finely assures physiological cardiac remodelling by epigenetic regulation of myomiRs, because inhibition of miR-208a and 208b increases the expression of their target proteins and stimulates the interaction among metabolic, contractile and epigenetic genes.
- Aerobic training
- cardiac hypertrophy
- ©2016 The Author(s)
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