Proteomic profiling of ribosomes from higher vs. lower responders to 10 weeks of resistance training

Objectives The purpose of this study was twofold: 1) develop a protocol sufficient to enrich and examine ribosome composition from human muscle tissue, and 2) determine if ribosomal composition differed between higher and lower responders to resistance training (RT). Methods Thirty-eight participants completed 10 weeks of RT (23 sessions) and 14 were stratified into higher (HR, n=7) and lower (LR, n=7) responders based on changes in vastus lateralis muscle cross-sectional area (VL mCSA) and mean myofiber cross-sectional area (fCSA) from baseline (PRE) to after the 23rd RT session (POST). Participants then performed one more RT session and biopsies were collected 24 h post-RT (POST-24 h) to examine acute adaptations to RT. HR and LR POST and POST-24 h biopsies were analyzed for ribosome content via ultracentrifugation (100,000 g , 3 h, 2 °C) through 20 % sucrose gradients, followed by shotgun proteomics to quantify ribosomal protein composition. Results Our protocol using ∼30 mg/sample produced exceptional ribosome enrichment, and proteomic analysis identified 74 distinct ribosomal proteins (92 % coverage of the putative 80 cytosolic ribosomal proteins). Despite robust phenotypic differences in hypertrophy between HR and LR (mCSA: +31 % vs. +3 %; fCSA: +29 % vs. −2%, p<0.05 for both outcomes), ribosomal protein composition showed no significant differences between groups, over time (POST to POST-24 h), or a group*time interaction (p>0.028 for all comparisons). Conclusions We present a highly effective ribosome enrichment protocol requiring minimal human muscle tissue. Despite successful enrichment, ribosomal protein composition was similar between hypertrophic phenotypes in response to an acute RT session after a 10-week RT intervention.