Quantitative Proteomic Analysis of Changes Related to Age and Calorie …

DOI: https://doi.org/10.1002/pmic.201700240

YounAh Kim, Oh Kwang Kwon, Sehyun Chae, Hee Jung Jung, Sanghyun Ahn, Ju Mi Jeon, Eunji Sung, SunJoo Kim, Sung Hwan Ki, Ki Wung Chung, Hae Young Chung, Young Suk Jung, Dae Hee Hwang, Sangkyu Lee

abstract

Calorie restriction (CR) is the most frequently studied mechanism for increasing longevity, protecting against stress, and delaying age‐associated diseases. Most studies have initiated CR in young animals to determine the protective effects against aging. Although aging phenomena are well‐documented, the molecular mechanisms of aging and CR remain unclear. In this study, we observe changes in hepatic proteins upon age‐related and diet‐restricted changes in the rat liver using quantitative proteomics. Quantitative proteomes are measured using tandem mass tag labeling followed by LC‐MS/MS. We compare protein levels in livers from young (6 months old) and old (25 months old) rats with 40% calorie‐restricted (YCR and OCR, respectively) or ad libitum diets. In total, 44 279 peptides and 3134 proteins are identified and 260 differentially expressed proteins are found. Functional enrichment analysis show that these proteins are mainly involved in glucose and fatty acid metabolism‐related processes, consistent with the theory that energy metabolism regulation is dependent on age‐related and calorie‐restricted changes in liver tissue. In addition, proteins mediating inflammation and gluconeogenesis are increased in OCR livers, but not YCR livers. These results show that CR in old rats might not have antiaging benefits because liver inflammation is increased.