title: Differential proteome analysis of aging in rat skeletal muscle.
abstract: To identify the mechanisms underlying muscle aging, we have undertaken a high-resolution differential proteomic analysis of gastrocnemius muscle in young adults, mature adults, and old LOU/c/jall rats. Two-dimensional gel electrophoresis and subsequent MALDI-ToF mass spectrometry analyses led to the identification of 40 differentially expressed proteins. Strikingly, most differences characterized old (30-month) animals, whereas young (7-month) and mature (18-month) adults exhibited similar patterns of expression. Important modifications in contractile (actin, myosin light-chains, troponins-T) and cytoskeletal (desmin, tubulin) proteins, and in essential regulatory proteins (gelsolin, myosin binding proteins, CapZ-beta, P23), likely account for dysfunctions in old muscle force generation and speed of contraction. Other features support decreases in cytosolic (triose-phosphate isomerase, enolase, glycerol-3-P dehydrogenase, creatine kinase) and mitochondrial (isocitrate dehydrogenase, cytochrome-c oxidase) energy metabolisms. Muscle aging is often associated with increased oxidative stress. Accordingly, we observed differential regulation of molecular chaperones (hsp20, hsp27, reticuloplasmin ER60) and of proteins implicated in reactive aldehyde detoxification (aldehyde dehydrogenase, glutathione transferase, glyoxalase). We further noticed up-regulation of proteins involved in transcriptional elongation (RNA capping protein) and RNA-editing (Apobec2). Most of these proteins were previously unrecognized as differentially expressed in old muscles, and they represent novel starting points for elucidating the mechanisms of muscle aging.
authors.affiliation: Human Nutrition Research Center, Nutrition and Protein Metabolism Laboratory, INRA UR551, Ceyrat, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Piec
authors.forename: Anne
authors.initials: A
authors.lastname: Listrat
authors.forename: Josette
authors.initials: J
authors.lastname: Alliot
authors.forename: Christophe
authors.initials: C
authors.lastname: Chambon
authors.forename: Richard G
authors.initials: RG
authors.lastname: Taylor
authors.forename: Daniel
authors.initials: D
authors.lastname: Bechet
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D003599:Cytoskeleton / Q000737:chemistry; D004734:Energy Metabolism; D008297:Male; D009124:Muscle Proteins / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000378:metabolism; D009210:Myofibrils / Q000737:chemistry; D020033:Protein Isoforms; D040901:Proteomics; D012313:RNA / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000032:analysis
chemical_list: D009124:Muscle Proteins; D020033:Protein Isoforms; D012313:RNA; D013482:Superoxide Dismutase