hamilton-inhibitionofmyostatin-2013.pdf (967.15 kB)
Inhibition of myostatin signaling through Notch activation following acute resistance exercise
journal contribution
posted on 2013-07-02, 00:00 authored by Matthew G MacKenzie, Lee HamiltonLee Hamilton, Mark Pepin, Amy Patton, Keith BaarMyostatin is a TGFβ family member and negative regulator of muscle size. Due to the complexity of the molecular pathway between myostatin mRNA/protein and changes in transcription, it has been difficult to understand whether myostatin plays a role in resistance exercise-induced skeletal muscle hypertrophy. To circumvent this problem, we determined the expression of a unique myostatin target gene, Mighty, following resistance exercise. Mighty mRNA increased by 6 h (82.9 ± 24.21%) and remained high out to 48 h (56.5 ± 19.67%) after resistance exercise. Further examination of the soleus, plantaris and tibialis anterior muscles showed that the change in Mighty mRNA at 6 h correlated with the increase in muscle size associated with this protocol (R(2) = 0.9996). The increase in Mighty mRNA occurred both independent of Smad2 phosphorylation and in spite of an increase in myostatin mRNA (341.8 ± 147.14% at 3 h). The myostatin inhibitor SKI remained unchanged. However, activated Notch, another potential inhibitor of TGFβ signaling, increased immediately following resistance exercise (83 ± 11.2%) and stayed elevated out to 6 h (78 ± 16.6%). Electroportion of the Notch intracellular domain into the tibialis anterior resulted in an increase in Mighty mRNA (63 ± 13.4%) that was equivalent to the canonical Notch target HES-1 (94.4 ± 7.32%). These data suggest that acute resistance exercise decreases myostatin signaling through the activation of the TGFβ inhibitor Notch resulting in a decrease in myostatin transcriptional activity that correlates well with muscle hypertrophy.
History
Journal
PLoS oneVolume
8Issue
7Article number
e68743Pagination
1 - 7Publisher
Public Library of ScienceLocation
San Francisco, Calif.Publisher DOI
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eISSN
1932-6203Language
engPublication classification
C1 Refereed article in a scholarly journalCopyright notice
2013, MacKenzie et al.Usage metrics
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Blotting, WesternHypertrophyMuscle ProteinsMyostatinPhosphorylationReceptors, NotchReverse Transcriptase Polymerase Chain ReactionSignal TransductionSmad2 ProteinTime Factorsskeletal musclesnotching signalingmessenger RNAgene expressionmuscle differentiationDNA transcriptionSMAD signalingsignal inhibitionScience & TechnologyMultidisciplinary SciencesScience & Technology - Other TopicsHUMAN SKELETAL-MUSCLEMESSENGER-RNAKINASE PHOSPHORYLATIONINTRACELLULAR DOMAINPROTEIN-METABOLISMPROMYOGENIC FACTORGENE-EXPRESSIONMICEMASSREGENERATION
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