Endurance Training Attenuates Catabolic Signals Induced by TNF-α in Muscle of Mice.
OBJECTIVE
To determine whether endurance training attenuates the negative effects induced by an acute injection of tumor necrosis factor-α (TNF-α) in skeletal muscle of mice.


METHODS
Trained (6 wk of endurance training at 60% of maximal velocity) and untrained mice were injected with TNF-α or vehicle and killed 6 h after. Tibialis anterior muscles were analyzed using Western blot and qRT-PCR for markers of inflammation and protein synthesis/degradation.


RESULTS
Independently of training, TNF-α increased the mRNA of cytokines and downregulated signals linked to protein synthesis. The phosphorylation of IKKα/β and IκBα induced by TNF-α was blunted in trained mice, suggesting altered NF-κB activation. This was associated with lower induction of several markers of protein degradation (FoxO1, MURF1, MAFbx, myostatin, Gabarapl1, and LC3BII/LC3BI ratio).


CONCLUSIONS
Endurance training protects skeletal muscle against the activation of protein degradation signaling pathways induced by TNF-α.
1Institute of Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, BELGIUM; and 2ELEONOR sprl, La Hulpe, BELGIUM.
Julie
J
Rodriguez
Rodrigo
R
Fernández-Verdejo
Nicolas
N
Pierre
Fabian
F
Priem
Marc
M
Francaux
D000818:Animals; D016207:Cytokines / Q000378:metabolism; D005260:Female; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D010807:Physical Endurance / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage*; D033921:Vesicular Transport Proteins
D016207:Cytokines; D008840:Microfilament Proteins; D012333:RNA, Messenger; D058570:TOR Serine-Threonine Kinases; D014409:Tumor Necrosis Factor-alpha; C546843:mTOR protein, mouse; C527550:Ccdc88a protein, mouse; D033921:Vesicular Transport Proteins