Hypertrophy of Rat Skeletal Muscle Is Associated with Increased SIRT1/Akt/mTOR/S6 and Suppressed Sestrin2/SIRT3/FOXO1 Levels

Despite the intensive investigation of the molecular mechanism of skeletal muscle hypertrophy, the underlying signaling processes are not completely understood. Therefore, we used an overload model, in which the main synergist muscles (gastrocnemius, soleus) of the plantaris muscle were surgically r...

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Bibliographic Details
Published in:International journal of molecular sciences 2021-07, Vol.22 (14), p.7588
Main Authors: Gombos, Zoltan, Koltai, Erika, Torma, Ferenc, Bakonyi, Peter, Kolonics, Attila, Aczel, Dora, Ditroi, Tamas, Nagy, Peter, Kawamura, Takuji, Radak, Zsolt
Format: Article
Language:English
Subjects:
AKT protein
anabolic signaling pathways
Animal models
Antioxidants
Bioavailability
Cell growth
Cytochrome
Enzymes
FOXO1 protein
Hydrogen sulfide
Hypertrophy
Kinases
Muscles
Musculoskeletal system
OGG1 protein
overload-induced hypertrophy
Overloading
Phosphorylation
Protein synthesis
Proteins
redox regulation
SIRT1 protein
Skeletal muscle
TOR protein
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Summary:Despite the intensive investigation of the molecular mechanism of skeletal muscle hypertrophy, the underlying signaling processes are not completely understood. Therefore, we used an overload model, in which the main synergist muscles (gastrocnemius, soleus) of the plantaris muscle were surgically removed, to cause a significant overload in the remaining plantaris muscle of 8-month-old Wistar male rats. SIRT1-associated pro-anabolic, pro-catabolic molecular signaling pathways, NAD and H2S levels of this overload-induced hypertrophy were studied. Fourteen days of overload resulted in a significant 43% (p < 0.01) increase in the mass of plantaris muscle compared to sham operated animals. Cystathionine-β-synthase (CBS) activities and bioavailable H2S levels were not modified by overload. On the other hand, overload-induced hypertrophy of skeletal muscle was associated with increased SIRT1 (p < 0.01), Akt (p < 0.01), mTOR, S6 (p < 0.01) and suppressed sestrin 2 levels (p < 0.01), which are mostly responsible for anabolic signaling. Decreased FOXO1 and SIRT3 signaling (p < 0.01) suggest downregulation of protein breakdown and mitophagy. Decreased levels of NAD+, sestrin2, OGG1 (p < 0.01) indicate that the redox milieu of skeletal muscle after 14 days of overloading is reduced. The present investigation revealed novel cellular interactions that regulate anabolic and catabolic processes in the hypertrophy of skeletal muscle.
ISSN:1422-0067
1661-6596
1422-0067
DOI:10.3390/ijms22147588