Title

The effects of acute aerobic and resistance exercise on mTOR signaling and autophagy markers in untrained human skeletal muscle

Document Type

Article

Department or Administrative Unit

Nutrition Exercise and Health Sciences

Publication Date

7-1-2021

Abstract

Purpose

Aerobic (AE) and resistance (RE) exercise elicit unique adaptations in skeletal muscle. The purpose here was to compare the post-exercise response of mTOR signaling and select autophagy markers in skeletal muscle to acute AE and RE.

Methods

In a randomized, cross-over design, six untrained men (27 ± 3 years) completed acute AE (40 min cycling, 70% HRmax) and RE (8 sets, 10 repetitions, 65% 1RM). Muscle biopsies were taken at baseline, and at 1 h and 4 h following each exercise. Western blot analyses were performed to examine total and phosphorylated protein levels. Upstream regulator analyses of skeletal muscle transcriptomics were performed to discern the predicted activation states of mTOR and FOXO3.

Results

Compared to AE, acute RE resulted in greater phosphorylation (P < 0.05) of mTORSer2448 at 4 h, S6K1Thr389 at 1 h, and 4E- BP1Thr37/46 during the post-exercise period. However, both AE and RE increased mTORSer2448 and S6K1Thr389 phosphorylation at 4 h (P < 0.05). Upstream regulator analyses revealed the activation state of mTOR was increased for both AE (z score, 2.617) and RE (z score, 2.789). No changes in LC3BI protein were observed following AE or RE (P > 0.05), however, LC3BII protein was decreased after both AE and RE at 1 h and 4 h (P < 0.05). p62 protein content was also decreased at 4 h following AE and RE (P < 0.05).

Conclusion

Both acute AE and RE stimulate mTOR signaling and similarly impact select markers of autophagy. These findings indicate the early adaptive response of untrained human skeletal muscle to divergent exercise modes is not likely mediated through large differences in mTOR signaling or autophagy.

Comments

This article was originally published in European Journal of Applied Physiology. The full-text article from the publisher can be found here.

Due to copyright restrictions, this article is not available for free download from ScholarWorks @ CWU.

Journal

European Journal of Applied Physiology

Rights

© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021

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