Proteome Oxidative Modifications and Impairment of Specific Metabolic Pathways During Cellular Senescence and Aging

Accumulation of oxidatively modified proteins is a hallmark of organismal aging in vivo and of cellular replicative senescence in vitro. Failure of protein maintenance is a major contributor to the age-associated accumulation of damaged proteins that is believed to participate to the age-related decline in cellular function. In this context, quantitative proteomics approaches, including 2-D gel electrophoresis (2-DE)-based methods, represent powerful tools for monitoring the extent of protein oxidative modifications at the proteome level and for identifying the targeted proteins, also referred as to the "oxi-proteome." Previous studies have identified proteins targeted by oxidative modifications during replicative senescence of human WI-38 fibroblasts and myoblasts and have been shown to represent a restricted set within the total cellular proteome that fall in key functional categories, such as energy metabolism, protein quality control, and cellular morphology. To provide mechanistic support into the role of oxidized proteins in the development of the senescent phenotype, untargeted metabolomic profiling is also performed for young and senescent myoblasts and fibroblasts. Metabolomic profiling is indicative of energy metabolism impairment in both senescent myoblasts and fibroblasts, suggesting a link between oxidative protein modifications and the altered cellular metabolism associated with the senescent phenotype of human myoblasts and fibroblasts.