Human Skeletal Muscle Possesses an Epigenetic Memory of Hypertrophy.
Level 3 - non-randomized controlled study
Prospective within-subject repeated-measures intervention study without a separate control group
PubMed 29382913 · doi:10.1038/s41598-018-20287-3
What was done
Genome-wide DNA methylation (850,000 CpG sites) and gene expression analyses were conducted in human skeletal muscle across three phases: hypertrophy induced by resistance loading, return of muscle mass to baseline during unloading, and subsequent hypertrophy following reloading. Epigenetic responses following a single acute exercise bout were also tracked.
What was found
Reloading produced a higher frequency of genome-wide hypomethylation (18,816 CpG sites) compared with initial loading (9,153 CpG sites). Specific genes (AXIN1, GRIK2, CAMK4, TRAF1) demonstrated hypomethylation and enhanced expression after loading that persisted through unloading when muscle mass returned to baseline. Another subset (UBR5, RPL35a, HEG1, PLA2G16, SETD3) showed hypomethylation and enhanced expression after loading, with the largest increases in hypomethylation, expression, and muscle mass occurring after reloading. Additionally, GRIK2, TRAF1, BICC1, and STAG1 were hypomethylated after a single exercise bout and retained this state 22 weeks later.
Why it matters
This study provides evidence that human skeletal muscle possesses an epigenetic memory of prior growth through enduring DNA hypomethylation, identifying candidate genes involved in muscle memory and adaptation to retraining.
Limits
The abstract does not state the sample size, participant demographics, baseline training status, or the precise magnitude of muscle mass changes. There is no separate untrained control group reported in the abstract.
Cited by
- supports Muscle memory involves an epigenetic component.