Comprehensive analysis of posttranslational protein modifications in aging of subcellular compartments

Abstract

Enzymatic and non-enzymatic posttranslational protein modifications by oxidation, glycation and acylation are key regulatory mechanisms in hallmarks of aging like inflammation, altered epigenetics and decline in proteostasis. In this study a mouse cohort was used to monitor changes of posttranslational modifications in the aging process. A protocol for the extraction of histones, cytosolic and mitochondrial proteins from mouse liver was developed and validated. In total, 6 lysine acylation structures, 7 advanced glycation endproducts, 6 oxidative stress markers, and citrullination were quantitated in proteins of subcellular compartments using HPLC-MS/MS. Methionine sulfoxide, acetylation, formylation, and citrullination were the most abundant modifications. Histone proteins were extraordinary high modified and non-enzymatic modifications accumulated in all subcellular compartments during the aging process. Compared to acetylation of histone proteins which gave between 350 and 305 µmol/mol leucine equivalents in young and old animals, modifications like acylation, glycation, and citrullination raised to 43%, 20%, and 18% of acetylation, respectively. On the other hand there was an age related increase of selected oxidative stress markers by up to 150%. The data and patterns measured in this study are mandatory for further studies and will strongly facilitate understanding of the molecular mechanisms in aging.

Proteomics in aging research: A roadmap to clinical, translational research

“…Numerous studies have implicated PTMs in the biology of aging and aging‐related diseases including metabolic syndrome, neurodegeneration, and heart disease. Alterations in PTM levels are strongly correlated with age in multiple animal and disease models (Baldensperger et al, 2020; Meyer et al, 2018; Santos & Lindner, 2017) and linked to age‐related diseases in human studies (Chaudhuri et al, 2018; Mnatsakanyan et al, 2018). For example, accumulation of AGEs and oxidative modifications are hallmarks of aging and metabolic diseases (Chaudhuri et al, 2018; Reeg & Grune, 2015).…”

“…Our meta‐analysis of plasma aging biomarkers identified the AGE/RAGE pathway (Figure 3, Table ), and AGEs may therefore be a promising PTM to examine in future aging biomarker studies in human plasma. Likewise, distinct changes in several types of acylation modifications are altered in aging and metabolic syndrome (Baldensperger et al, 2020; Carrico et al, 2018; Meyer et al, 2018). Yet, little is known about the role these and other modifications play in the progression of aging and related diseases.…”

“…Alterations in PTM levels are strongly correlated with age in multiple animal and disease models (Baldensperger et al, 2020;Meyer et al, 2018;Santos & Lindner, 2017) and linked to age-related diseases in human studies (Chaudhuri et al, 2018;Mnatsakanyan et al, 2018).…”

Mapping sites of carboxymethyllysine modification on proteins reveals its consequences for proteostasis and cell proliferation

“…Glycation of extracellular proteins such as hemoglobin HbA1c (Shapiro et al, 1980) or collagen (Avery and Bailey, 2005) is well described, but reports on glycation of intracellular proteins are still scarce. Examples of those are histones (Ansari et al, 2018;Baldensperger et al, 2020;Galligan et al, 2018;Guedes et al, 2011;Mir et al, 2014;Zheng et al, 2019;Zheng et al, 2020), mitochondrial proteins (Hamelin et al, 2007;Rosca et al, 2005;Wang et al, 2009), the 20S proteasome (Queisser et al, 2010), enzymes involved in energy production (Snow et al, 2007), small heat shock proteins (Oya-Ito et al, 2006;Schalkwijk et al, 2006;Sudnitsyna and Gusev, 2017) and the sodium channel Nav1.8 (Bierhaus et al, 2012). Glycation is increasingly seen as a driver of metabolic disease and aging, and it may elicit specific effects by targeting signaling proteins (Chaudhuri et al, 2018;Kold-Christensen and Johannsen, 2020).…”

Editorial: Dysregulated Protein Homeostasis in the Aging Organism

“…Dysregulated protein homeostasis arises from dysfunctional chaperone-mediated protein folding and/or impaired UPS- and/or ALS-mediated protein degradation and is associated with several age-related diseases including Alzheimer’s and Parkinson’s disease, among many others ( Figure 1 ) ( López-Otín et al, 2013 ). The accumulation of posttranslational modified proteins that accumulate over time is another striking feature in aging organisms ( Baldensperger et al, 2020 ). On the one hand, this accumulation is partly a consequence of the failing protein homeostasis, on the other hand it actively contributes to the dysfunction of protein refolding and degradation as demonstrated in the case of protein glycation ( Uchiki et al, 2012 ) and oxidation ( Breusing and Grune, 2008 ).…”