The 24-hour molecular landscape after exercise in humans reveals MYC is sufficient for muscle growth.
Level 4 - case-series / case-control
Human prospective time-series biopsy study combined with mechanistic mouse experiment
PubMed 39482487 · doi:10.1038/s44319-024-00299-z
What was done
Human muscle biopsies were collected across a 24-hour time course after a single bout of resistance exercise to track DNA methylation and transcriptional responses. To determine if the key identified regulator, MYC, was sufficient to induce hypertrophy, researchers delivered periodic pulses of MYC expression in the skeletal muscle of adult mice over 4 weeks.
What was found
The abstract reports temporal sequences rather than specific quantitative values. In humans: (1) DNA methylome changes at 30 minutes corresponded to genes upregulated at 3 hours; (2) transcription- and translation-initiation factor transcripts surged between 3 and 8 hours; (3) global protein-coding gene expression changes peaked at 8 hours; (4) ribosome-related mRNAs dominated between 8 and 24 hours; and (5) methylation-regulated MYC was identified as a central transcription factor throughout recovery. In mice, transient MYC pulsing increased muscle mass and fiber size in the soleus.
Why it matters
This work maps the early epigenetic and transcriptomic timeline of resistance exercise in human muscle and identifies controlled MYC pulsing as a potential mechanistic target for promoting muscle growth.
Limits
The abstract does not state the human participant sample size, demographics, or exact quantitative values (effect sizes, fold changes). Hypertrophic sufficiency of MYC was demonstrated only in mouse soleus muscle, so human in vivo interventional efficacy remains unconfirmed.
Cited by
- supports Post-exercise gene expression related to muscle anabolism typically peaks between 3 and 6 hours following a workout.