Project description:Exercise is an effective strategy in the prevention and treatment of metabolic diseases. Alterations in the skeletal muscle proteome, including post-translational modifications, regulate its metabolic adaptations to exercise. Here, we examined the effect of high-intensity interval training (HIIT) on the proteome and acetylome of human skeletal muscle, revealing the response of 3168 proteins and 1263 lysine acetyl-sites on 464 acetylated proteins. We identified novel protein adaptations to exercise training involved in metabolism and excitation-contraction coupling. Furthermore, HIIT increased the acetylation of mitochondrial proteins, particularly those of complex V, likely via non-enzymatic mechanisms. We also highlight the regulation of novel exercise-responsive histone acetyl-sites. These data demonstrate the plasticity of the skeletal muscle proteome and acetylome, providing insight into the regulation of contractile, metabolic and transcriptional processes within skeletal muscle. Herein, we provide a substantial hypothesis-generating resource to stimulate further mechanistic research investigating how exercise improves metabolic health.
Project description:Muscle contraction during exercise is the major stimulus for the release of peptides and proteins (myokines) that are supposed to take part in the benefical adaptation to exercise. We hypothesize that application of an in vitro exercise stimulus as electric pulse stimulation (EPS) to human myotubes enables the investigation of the human muscle secretome in a clearly defined model. We applied EPS for 24 h to primary human myotubes and studied the whole genome-wide transcriptional response and as well as the release of candidate myokines. We observed 183 differentially regulated transcripts with fold-changes > 1.3. The transcriptional response resembles several properties of the in vivo situation in the skeletal muscle after endurance exercise, namely significant enrichment of pathways associated with interleukin and chemokine signaling, lipid metabolism, and anti-oxidant defense; notably without increased release of creatin kinase. Multiplex immunoassays verified the translation of the transcriptional response of several myokines into high secretion levels (IL6, IL8, CXCL1, LIF, CSF3, IL1B, TNF) and identified an increased secretion of additional cytokines (IL2, IL4, IL13, IL17A). Inhibitor studies and immunoblotting revealed the participation of ERK1/2 and AMPK dependent pathways in the upregulation of myokines. To conclude our data highlight the importance of skeletal muscle cells per se as endocrine cells. This in vitro exercise model is not only suitable to identify known and novel exercise-regulated myokines but it might be applied to primary human myotubes obtained from different muscle biopsy donors to study molecular mechanisms of the individual response to exercise. We performed gene expression microarray analysis of myotubes in vitro stimulated by EPS and control myotubes