Developmental proteomics: the importance of age specific differences in the human plasma proteome
Abstract
Human plasma proteomics studies have to date focused largely on: specific disease settings, detecting the highest number of proteins, as well as the effect of therapeutics on plasma protein expression. The majority of these studies have been adult-based, with very few studies and hence limited knowledge of the plasma proteome in neonates, infants and children. Developmental Proteomics, with a focus on age-specific differences in the human plasma proteome can be extremely useful in providing much needed knowledge, particularly as proteomics edges towards clinical applications/diagnostics. This presentation will outline the importance of unraveling age-based differences in the human plasma proteome and will include the latest developments in this field.
Effect of aging on lipidomic changes in mouse serum, kidney, and heart by nanoflow UHPLC-ESI-MS/MS
Abstract
Aging is characterized in part by the progressive decline in metabolic function with the increased risks of disease and death, and accompanied by the intracellular accumulation of reactive oxygen species that damage proteins, DNA, and lipids. In particular, lipids are engaged in various cellular processes such as cell signaling, energy storage, proliferation, and apoptosis. Since alterations in lipid metabolism may trigger metabolic disorders and the onset of metabolic diseases, changes in lipid profiles can be closely related with aging. This presentation introduces a comprehensive lipidomic comparison between the 4- and 25-month-old C57BL/6N mice which was done to investigate the age-induced changes in lipid profiles of serum, kidney, and heart. Due to the complicated structure of lipids, lipidomic analysis in biological systems requires a systematic determination of lipid molecular structures followed by targeted quantification. In this study, the effect of aging on the lipid profiles of mice was investigated at the molecular level using nanoflow ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, resulting in an identification of 542 lipids with the structural determination followed by selected reaction monitoring (SRM) based quantification of 279 targeted lipid species. Quantitative analysis revealed significant changes upon aging that mainly involved decreased levels in the three types of samples. An exception was the significant increases in most triacylglycerols in heart tissue. Kidney was influenced more by aging than serum and heart. Highly abundance lipids with significant decreases (> 2-fold, p < 0.01) were lysophosphatidic acid 18:1, lysophosphatidylinositol 20:4, and ceramide d:18:1/24:0 in serum, and lysophosphatidylglycerol 16:0 in heart tissue, and eight phosphatidylethanolamines (20:4, 22:6, 36:2, 36:3, 38:4, 38:5, 38:6, 40:6, and 40:7), two cardiolipins (72:7 and 72:8), and lysophosphatidylcholine 18:0 in kidney tissue. The present study demonstrates the potential of lipidomic analysis to understand the role of lipids during the process of aging and age-related adult diseases, and to assess lipidomic signatures for the early detection or prediction of aging in the future.
Korea Research Institute of Bioscience & Biotechnology
Title
The role of Dlk1-Dio3 miRNA cluster in muscle aging
Abstract
Skeletal muscle mass and function gradually decrease with age, contributing to morbidity, mortality and overall decline in quality of life in the elderly, but the underlying mechanisms are largely unknown. Here, we found that the majority of microRNAs (miRNAs) in the Dlk1-Dio3 cluster induced antiatrophic phenotypes in fully differentiated myotubes, increasing their diameters. Notably, a group of miRNAs in the cluster inhibited the protein expression of Atrogin-1, a muscle-specific E3 ligase, by interacting with its 3′ untranslated region (UTR). Intramuscular delivery of adenovirus expressing miR-376c-3p, one of the most effective miRNAs in myotube thickening, dramatically ameliorated skeletal muscle atrophy and improved resistance to muscle fatigue in old mice. Consistent with our previous findings in mice, the expression of miRNAs in the cluster showed a significant decline with age in human muscle. Collectively, our study suggests that miRNAs in the cluster might be valuable targets to develop therapeutics for sarcopenia.
Proteomic analysis of an Alzheimer's-in-a-dish model
Abstract
Alzheimer’s disease (AD) is the most common form of dementia, characterized by two pathological hallmarks: β-amyloid plaques and neurofibrillary tangles. It is hypothesized that the accumulation of Aβ causes the formation of neurofibrillary tangles, but this has not been experimentally proven in any animal models. Recently, we developed a human neural cell culture model of AD based on a three-dimensional (3D) culture of neural stem cells carrying multiple familial AD mutations. This AD-in-a-dish model was able to recapitulate robust deposition of Aβ plaques and Aβ-driven tau pathology. However, the molecular mechanism of AD pathology is yet to be fully elucidated. In the present study, global proteomics and tau phosphoproteomics were performed in the AD-in-a-dish model in order to understand the early events of AD pathology following Aβ accumulation and the Aβ-driven tau pathology, respectively. For global proteomics, tryptic peptides from cytoplasmic and membrane fractions were labeled with TMT isobaric mass tags, fractionated by basic pH reversed-phase liquid chromatography, and analyzed by LC-MS/MS. For tau phosphoproteomics, immunoaffinity-purified tau proteins were subjected to trypsin digestion, followed by phosphopeptide enrichment and LC-MS/MS analysis. As a result, a total of 1,046 proteins were differentially expressed in AD neuronal cells with a P-value less than 0.05, and the top canonical pathways included mitochondrial dysfunction, oxidative-stress response, protein ubiquitination, and various signaling pathways. Tau phosphoproteomics also confirmed that tau phosphorylation in AD neuronal cells was increased at multiple sites in a time-dependent manner. Our proteomics dataset will be valuable for investigation on the molecular mechanisms underlying Aβ-driven tau pathology in AD.
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