Remodeling of the Human Skeletal Muscle Proteome Found After Long-Term Endurance Training but Not After Strength Training

Regular exercise training has tremendous systemic tissue-specific health benefits, but the molecular adaptations to long-term exercise training are not completely understood. The aim of the current study was to investigate the skeletal muscle proteome of highly endurance-trained, strength-trained and untrained individuals and performed exercise- and sex-specific analyses. As a previous investigation from our lab showed limited baseline differences at the gene expression level between highly strength-trained males and untrained males, we hypothesized that the that long-term resistance training results in baseline differences in protein abundances. Additionally, we hypothesized that endurance-trained individuals would have a greater abundance of mitochondrial proteins compared with the untrained and the strength-trained individuals. Liquid-chromatography followed by mass-spectrometry (LC-MS/MS) was performed on skeletal muscle tissue from all individuals. A total of 6713 proteins were detected, with 4269 proteins being expressed in at least 50% of the samples. Over 650 proteins were differentially expressed in the skeletal muscle of endurance-trained individuals compared with controls. Strikingly, 92% of the shared proteins with higher expression in both the male and female endurance groups were known mitochondrial proteins. In contrast to the findings in endurance trained individuals, minimal differences were found in strength-trained individuals and between females and males. Lastly, to determine the preventive-medicine capabilities of long-term training, a co-expression network and comparative literature analysis revealed key proteins and pathways related to the health benefits of exercise, which were primarily related to differences in mitochondrial protein abundance. This network is available as an interactive database resource ( https://inetmodels.com ) where investigators can correlate clinical data with global gene and protein expression data for hypothesis generation. In conclusion, we suggest that long-term endurance training but not strength training results in a r emodeling of the skeletal muscle proteome in humans. This work was financially supported by grants from the Swedish Research Council (2018-02932), the Swedish Center for Sports Research (2020-D0007, P2022-0082), the National Science Foundation (Award Number: 1951792), the Whitaker International Program and the Karolinska Institute. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.