Resistance exercise training modulates acute gene expression during human skeletal muscle hypertrophy

Abstract

We sought to determine whether acute resistance exercise (RE)-induced gene expression is modified by RE training. We studied the expression patterns of a select group of genes following an acute bout of RE in naïve and hypertrophying muscle. Thirteen untrained subjects underwent supervised RE training for 12 wk of the nondominant arm and performed an acute bout of RE 1 wk after the last bout of the training program (training+acute). The dominant arm was either unexercised (control) or subjected to the same acute exercise bout as the trained arm (acute RE). Following training, men (14.8 ± 2.8%; P < 0.05) and women (12.6 ± 2.4%; P < 0.05) underwent muscle hypertrophy with increases in dynamic strength in the trained arm (48.2 ± 5.4% and 72.1 ± 9.1%, respectively; P < 0.01). RE training resulted in attenuated anabolic signaling as reflected by a reduction in rpS6 phosphorylation following acute RE. Changes in mRNA levels of genes involved in hypertrophic growth, protein degradation, angiogenesis, and metabolism commonly expressed in both men and women was determined 4 h following acute RE. We show that RE training can modify acute RE-induced gene expression in a divergent and gene-specific manner even in genes belonging to the same ontology. Changes in gene expression following acute RE are multidimensional, and may not necessarily reflect the actual adaptive response taking place during the training process. Thus RE training can selectively modify the acute response to RE, thereby challenging the use of gene expression as a marker of exercise-induced adaptations.

Ribosome biogenesis adaptation in resistance training-induced human skeletal muscle hypertrophy

“…We hypothesize that rDNA transcription may be upregulated at a later time point during postexercise recovery. In line with this hypothesis, Nader et al (24) recently reported an increase in 45S rRNA 4 h post-RE, 3 hours later than our biopsy sampling time point. Convincingly, although the levels of 45S pre-rRNA after exercise were decreased in the present study, they were positively correlated with the levels of TIF-IA phosphorylation (but not UBF phosphorylation).…”

The hitchhiker’s guide to PGC-1α isoform structure and biological functions

“…the inclusion of the new exon 6 and the premature stop codon at 266 aa). Pgc-1α2, -α3 and -α4 mRNA and protein levels are induced by hypertrophic stimuli in skeletal muscle [36,37] and by cold exposure in BAT, but do not drive the well-known oxidative phenotype induced by other variants [36]. Notably, PGC-1α4 has been shown to exert physiological effects previously unreported for a member of the PGC-1 family.…”

“…The alternative gene promoter is highly conserved between species and has been shown to be active in human skeletal muscle [34][35][36]. Accordingly, the novel PGC-1α isoforms are detected in skeletal muscle after exercise [35][36][37].…”

“…Alternative promoter-derived Pgc-1α4, which drives muscle hypertrophy, is induced only in exercise programmes that include a resistance component, whereas its expression is unaffected by 8 weeks of aerobic cycling [36]. In addition, a 12-week progressive weight lifting programme specifically induces isoforms Pgc-1α2, Pgc-1α3 and Pgc-1α4 from the novel promoter [37]. However, other research shows that both promoters can be activated independent of the exercise intervention [60,61].…”

Peroxisome Proliferator-activated Receptor γ Coactivator-1 α Isoforms Selectively Regulate Multiple Splicing Events on Target Genes

“…Upon specific physiological signals, a single PGC-1␣ gene expresses different variants with discrete biological roles (2)(3)(4). For example, in skeletal muscle, resistance exercise and ␤ 2 -adrenergic stimulation activate a distal PGC-1␣ promoter that controls the expression of alternative isoforms PGC-1␣2, PGC-1␣3, and PGC-1␣4 (3,5,6), which undergo additional alternative splicing of their primary transcript (Fig. 1A) (3).…”