Differential Cysteine Labeling and Global Label-Free Proteomics Reveals an Altered Metabolic State in Skeletal Muscle Aging

Brian McDonagh, Giorgos K. Sakellariou, Neil T. Smith, Philip Brownridge, Malcolm J. Jackson

The molecular mechanisms underlying skeletal muscle aging and associated sarcopenia have been linked to an altered oxidative status of redox sensitive proteins. Reactive oxygen and reactive nitrogen species (ROS/RNS) generated by contracting skeletal muscle are necessary for optimal protein function, signaling and adaptation. To investigate the redox proteome of aging gastrocnemius muscles from adult and old male mice muscle we developed a label free quantitative proteomic approach that includes a differential Cysteine labelling step. The approach allows simultaneous identification of up and down regulated proteins between samples in addition to the identification and relative quantification of the reversible oxidation state of susceptible redox Cysteine residues. Results from muscles of adult and old mice indicate significant changes in the content of chaperone, glucose metabolism and cytoskeletal regulatory proteins including Protein DJ-1, cAMP-dependent protein kinase type II, 78kDa glucose regulated protein and a reduction in the number of redox responsive proteins identified in muscle of old mice. Results demonstrate skeletal muscle aging causes a reduction in redox sensitive proteins involved in the generation of precursor metabolites and energy metabolism indicating a loss in the flexibility of the redox energy response. Data is available via ProteomeXchange with identifier PXD001054.