scholarly journals Akt signalling through GSK-3β, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy

2006 ◽  
Vol 576 (3) ◽  
pp. 923-933 ◽  
Author(s):  
Bertrand Léger ◽  
Romain Cartoni ◽  
Manu Praz ◽  
Séverine Lamon ◽  
Olivier Dériaz ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Muscle Hypertrophy ◽  
Skeletal Muscle Hypertrophy ◽  
Gsk 3Β

Wnt/β-catenin signaling activates growth-control genes during overload-induced skeletal muscle hypertrophy

2005 ◽  
Vol 289 (4) ◽  
pp. C853-C859 ◽  
Author(s):  
Dustin D. Armstrong ◽  
Karyn A. Esser
Keyword(s):  
Skeletal Muscle ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Muscle Hypertrophy ◽  
Glycogen Synthase ◽  
Wnt Signaling Pathway ◽  
Growth Control ◽  
Skeletal Muscle Hypertrophy ◽  
Study Results ◽  
Gsk 3Β

β-Catenin is a transcriptional activator shown to regulate the embryonic, postnatal, and oncogenic growth of many tissues. In most research to date, β-catenin activation has been the unique downstream function of the Wnt signaling pathway. However, in the heart, a Wnt-independent mechanism involving Akt-mediated phosphorylation of glycogen synthase kinase (GSK)-3β was recently shown to activate β-catenin and regulate cardiomyocyte growth. In this study, results have identified the activation of the Wnt/β-catenin pathway during hypertrophy of mechanically overloaded skeletal muscle. Significant increases in β-catenin were determined during skeletal muscle hypertrophy. In addition, the Wnt receptor, mFrizzled (mFzd)-1, the signaling mediator disheveled-1, and the transcriptional co-activator, lymphocyte enhancement factor (Lef)-1, are all increased during hypertrophy of the overloaded mouse plantaris muscle. Experiments also determined an increased association between GSK-3β and the inhibitory frequently rearranged in advanced T cell-1 protein with no increase in GSK-3β phosphorylation (Ser9). Finally, skeletal muscle overload resulted in increased nuclear β-catenin/Lef-1 expression and induction of the transcriptional targets c-Myc, cyclin D1, and paired-like homeodomain transcription factor 2. Thus this study provides the first evidence that the Wnt signaling pathway induces β-catenin/Lef-1 activation of growth-control genes during overload induced skeletal muscle hypertrophy.

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

2021 ◽  
Vol 22 (14) ◽  
pp. 7588
Author(s):  
Zoltan Gombos ◽  
Erika Koltai ◽  
Ferenc Torma ◽  
Peter Bakonyi ◽  
Attila Kolonics ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Hypertrophy ◽  
Male Rats ◽  
Cellular Interactions ◽  
Molecular Signaling ◽  
Protein Breakdown ◽  
Rat Skeletal Muscle ◽  
Plantaris Muscle ◽  
Skeletal Muscle Hypertrophy ◽  
Intensive Investigation

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.

scholarly journals Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training

2019 ◽  
Vol 6 ◽  
Author(s):  
Gary John Slater ◽  
Brad P. Dieter ◽  
Damian James Marsh ◽  
Eric Russell Helms ◽  
Gregory Shaw ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Muscle Hypertrophy ◽  
Skeletal Muscle Hypertrophy ◽  
Energy Surplus
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