Exercise-induced skeletal muscle remodeling and metabolic adaptation: redox signaling and role of autophagy.
CONCLUSIONS
Skeletal muscle is a highly plastic tissue. Exercise evokes signaling pathways that strongly modify myofiber metabolism and physiological and contractile properties of skeletal muscle. Regular physical activity is beneficial for health and is highly recommended for the prevention of several chronic conditions. In this review, we have focused our attention on the pathways that are known to mediate physical training-induced plasticity.


BACKGROUND
An important role for redox signaling has recently been proposed in exercise-mediated muscle remodeling and peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) activation. Still more currently, autophagy has also been found to be involved in metabolic adaptation to exercise.


RESULTS
Both redox signaling and autophagy are processes with ambivalent effects; they can be detrimental and beneficial, depending on their delicate balance. As such, understanding their role in the chain of events induced by exercise and leading to skeletal muscle remodeling is a very complicated matter. Moreover, the study of the signaling induced by exercise is made even more difficult by the fact that exercise can be performed with several different modalities, with this having different repercussions on adaptation.


CONCLUSIONS
Unraveling the complexity of the molecular signaling triggered by exercise on skeletal muscle is crucial in order to define the therapeutic potentiality of physical training and to identify new pharmacological compounds that are able to reproduce some beneficial effects of exercise. In evaluating the effect of new "exercise mimetics," it will also be necessary to take into account the involvement of reactive oxygen species, reactive nitrogen species, and autophagy and their controversial effects.
1 Pathophysiology and Treatment of Muscle Wasting Disorders Unit, IRCCS San Raffaele Pisana , Rome, Italy .
Elisabetta
E
Ferraro
Anna Maria
AM
Giammarioli
Sergio
S
Chiandotto
Ilaria
I
Spoletini
Giuseppe
G
Rosano
D000818:Animals; D001343:Autophagy / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006801:Humans; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D047495:PPAR gamma / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
D047495:PPAR gamma