Skeletal muscle DNA methylation and mRNA responses to a bout of higher versus lower load resistance exercise in previously trained men

Abstract

We sought to determine the skeletal muscle genome-wide DNA methylation and mRNA responses to one bout of lower-load (LL) versus higher-load (HL) resistance exercise. Trained college-aged males (n=11, 23+/-4 years old, 4+/-3 years self-reported training) performed LL or HL bouts to failure separated by one week. The HL bout (i.e., 80 Fail) consisted of four sets of back squats and four sets of leg extensions to failure using 80% of participants estimated one-repetition maximum (i.e., est. 1-RM). The LL bout (i.e., 30 Fail) implemented the same paradigm with 30% of est. 1-RM. Vastus lateralis muscle biopsies were collected before, 3 hours, and 6 hours after each bout. Muscle DNA and RNA were batch-isolated and analyzed using the 850k Illumina MethylationEPIC array and Clariom S mRNA microarray, respectively. Performed repetitions were significantly greater during the 30 Fail versus 80 Fail (p<0.001), although total training volume (sets x reps x load) was not significantly different between bouts (p=0.571). Regardless of bout, more CpG site methylation changes were observed at 3- versus 6-hours post exercise (239,951 versus 12,419, respectively; p<0.01), and nuclear global ten-eleven translocation (TET) activity, but not global DNA methyltransferase activity, increased 3- and 6-hours following exercise regardless of bout. The percentage of genes significantly altered at the mRNA level that demonstrated opposite DNA methylation patterns was greater 3- versus 6-hours following exercise (~75% versus ~15%, respectively). Moreover, high percentages of genes that were up- or downregulated 6 hours following exercise also demonstrated significantly inversed DNA methylation patterns across one or more CpG sites 3 hours following exercise (65% and 82%, respectively). While 30 Fail decreased DNA methylation across various promoter regions versus 80 Fail, transcriptome-wide mRNA and bioinformatics indicated that gene expression signatures were largely similar between bouts. Bioinformatics overlay of DNA methylation and mRNA expression data indicated that genes related to Focal adhesion, MAPK signaling, and PI3K-Akt signaling were significantly affected at the 3- and 6-hour time points, and again this was regardless of bout. In conclusion, extensive molecular profiling suggests that post-exercise alterations in the skeletal muscle DNA methylome and mRNA transcriptome elicited by LL and HL training bouts to failure are largely similar, and this could be related to equal volumes performed between bouts.

The interactive effect of sustained sleep restriction and resistance exercise on skeletal muscle transcriptomics in young females

“…Our results however indicate that irrespective of sleep, ~2000-3000 genes were still differentially expressed 48 h post the completion of three resistance exercise sessions. In muscle biopsies taken up to 24 h post resistance exercise, similarly large transcriptomic responses have previously been reported(20,51,52). The transient nature of the transcriptional response to resistance exercise, however, is not well characterised.…”

Human skeletal muscle methylome after low carbohydrate energy balanced exercise

“…It is currently unknown what the impact of achieving energy balance under low-CHO conditions has on the SkM response to exercise using an untargeted whole-genome ´omic´ approach. The epigenetic modification of DNA methylation across the genome (methylome) has been demonstrated to be a dynamic response that precedes changes in gene expression in SkM after acute exercise (14)(15)(16). Both acute exercise and chronic training can predominantly decrease DNA methylation (i.e., hypomethylation) in both human and rodent SkM (14)(15)(16)(17)(18)(19)(20).…”

“…The epigenetic modification of DNA methylation across the genome (methylome) has been demonstrated to be a dynamic response that precedes changes in gene expression in SkM after acute exercise (14)(15)(16). Both acute exercise and chronic training can predominantly decrease DNA methylation (i.e., hypomethylation) in both human and rodent SkM (14)(15)(16)(17)(18)(19)(20). This is perhaps because hypomethylation, especially in gene regulatory regions such as promoters, allows transcription factor binding to enable gene expression to occur (21,22).…”

“…It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted January 20, 2023. ; https://doi.org/10.1101/2023.01. 19.524676 doi: bioRxiv preprint (16,19), high-intensity (15) and aerobic exercise (18,23,24). Importantly, DNA methylome studies have identified novel exercise-responsive genes in human SkM that have not been previously highlighted in mRNA/transcriptome studies (14,25,26).…”

“…This is perhaps because hypomethylation, especially in gene regulatory regions such as promoters, allows transcription factor binding to enable gene expression to occur (21,22). Indeed, there seems to be a trend that a larger proportion of the genes that demonstrate hypomethylation are associated with a 'gene turn on' profile in SkM in response to resistance/strength (16,19), high-intensity (15) and aerobic exercise (18,23,24). Importantly, DNA methylome studies have identified novel exercise-responsive genes in human SkM that have not been previously highlighted in mRNA/transcriptome studies (14,25,26).…”