Acute Aerobic Exercise Regulates The Phosphoproteome, But Not Acetylproteome, In Human Skeletal Muscle

The molecular mechanisms of exercise on metabolic health remain incompletely understood. Post-translational modifications (PTMs) are a promising molecular regulatory mediator of exercise, which include a wide array of chemical modifications that occur after a protein is synthesized, altering its structure and/or function. Two of the most critical PTMs for modulating skeletal muscle protein function and stability after exercise are phosphorylation and acetylation. However, an integrated analysis of PTMs and metabolomic changes after acute aerobic exercise (AAE) or acute resistance exercise (ARE) has not been previously performed. PURPOSE: Identify acute exercise regulated PTMs and metabolites to unveil the underpinning molecular mechanisms of the distinct metabolic adaptations to AAE or ARE in skeletal muscle. METHODS: Muscle biopsies were obtained from eight male and female participants before, immediately after, and 1 hr after a single session of AAE or ARE. The exercise-regulated skeletal muscle phosphoproteome and acetylproteome were measured by liquid chromatography (LC) tandem mass spectrometry (MS) with tandem mass tag labeling. Targeted metabolomics including amino metabolites and TCA analytes were measured by LC-MS and gas chromatography MS, respectively. The muscle transcriptome was measured by RNA-seq. RESULTS: We observed significantly (P < 0.05 with FC > 0.5) increased expression of 492 and 359 gene transcripts at 1 hr after AAE and ARE, respectively, with >57% being common to both exercises. Metabolomics analyses revealed significantly reduced (P < 0.05 with FC > 0.15) amino metabolite concentration (including lysine, α-amino-adipic-acid, glutamate, glutamine, arginine, aspartate, and others) immediately after AAE, but not ARE. Although the global proteome and acetylproteome were unaltered immediately after AAE or ARE, AAE significantly (P < 0.05 with FC > 1.3) altered 1,353 (1,173 up and 180 down) phosphopeptides, accounting for 13% of the phosphoproteome. ARE induced minimal phosphoproteomic changes. Furthermore, many of the phosphoproteomic changes with AAE appear to be linked to metabolomic changes. CONCLUSIONS: These findings support the idea that alterations in the phosphoproteome after acute exercise are regulated by the metabolic stimulus of the exercise bout. Supported by: Supported by NIH Grant R01 AG062859