Acute Endurance Exercise-mediated Autophagy Occurs in Parallel with The Simultaneous Activation of mTOR

Endurance exercise (EE) is a strong inducer of autophagy in the heart. However, the exact mechanisms responsible for exercise-induced cardiac autophagy remain unclear. Here we showed that acute EE induces autophagy despite the mTOR activation. C57BL/6 mice were randomly assigned to either exercise (n=7) or sedentary group (n=7). After acclimatization, mice were trained for 60 min on a motorized treadmill at 12m/min on a 0% grade. Hearts were excised immediately 1-hour post exercise and homogenized for Western blot analyses. We found that EE significantly increased autophagy (an increase in the ratio of LC3II to LC3I and a reduction in P62) without changes in the levels of Beclin 1; however, ATG7 essential for autophagsome formation was highly increased compared to the sedentary group. Intriguingly, in contrast to the canonical autophagy pathway, EE promoted autophagy in parallel with mTOR activation. Accordingly, we measured both upstream (Akt) and downstream p70s6k) signaling of mTOR, respectively and co...