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Aging is characterized by an increased accumulation of damaged macromolecules and oxidized protein build up is considered to be a hallmark of cellular aging. Advanced glycation end products (AGE) have been analyzed in aging human peripheral blood lymphocytes since such glycoxidative modifications have been reported to increase with age in a variety of cellular and tissular systems and are believed to contribute to the intracellular age-related accumulation of damaged proteins, a process that has been associated with the cellular functional deficits that occur with age. The pattern of glycated protein has been studied using two dimensional gel electrophoresis followed by Western blotting with an anti-AGE antibody. The protein silver stain and the immunoblot patterns were not superimposable indicating that glycoxidative modifications are targeting only a restricted set of proteins. Among these preferential protein targets, seven of them exhibited a significant age-related increased immunoreactivity with the anti-AGE antibody suggesting that the corresponding modified proteins might serve as biomarkers of aging lymphocytes [ ]. Other age-related protein modifications such as carbonyl formation and conjugation with the lipid peroxidation product 4-hydroxy-2-nonenal are also currently studied. The age-related accumulation of altered protein raises the problem of the efficacy of intracellular protein maintenance, in particular the protein degradation and the protein repair systems. Indeed, if these systems that take care of the removal or repair of damaged proteins are affected with aging, they would therefore directly contribute to the increased intracellular load of functionally impaired protein. Since cytosolic oxidized protein degradation and basal protein turnover have been shown to be mostly carried out by the proteasomal system, the fate of proteasome in aging has been addressed and a decline of proteasomal proteolytic activity has been reported [ ]. The impact of aging on human lymphocyte 26S proteasome has been recently investigated and age-related alterations of proteasome structure and function have been evidenced. Indeed, we observed a decline of 26S proteasome specific activity which is correlated to an increasing yield of post-translational modifications of proteasome subunits [ ]. In fact, some proteasome subunits and particularly assembly and catalytic subunits are specifically modified with age. According to bidimensional westernblotting, some subunits were found either glycated, conjugated with the lipid peroxidation product 4-hydroxy-2-nonenal or even ubiquitinated. In vitro treatment of the proteasome by glyoxal, that promotes the formation of Nℇ-carboxymethyllysine adducts, or by the lipid peroxidation product 4-hydroxy-2-nonenal was found to inactivate its peptidase activities although to different extent. In other studies aimed at monitoring the effect of oxidative stress on proteasome structure and function, we have shown on an in vivo rat model that coronary occlusion/reperfusion resulted in inactivation of the proteasome [ ]. This inactivation is associated with selective modification by the lipid peroxidation product 4-hydroxy-2-nonenal of three 20S proteasome α-subunits. In contrast, the observed inhibition of proteasome upon exposure of human keratinocytes to UV stress was mainly due to the stress-induced formation of endogeneous inhibitors, including certain oxidatively modified proteins [ ]. In addition, the role of the peptide methionine sulfoxide reductase, one of the very few protein repair enzyme described, and its possible implication in the age-related decline of protein maintenance has been investigated. The peptide methionine sulfoxide reductase system (Msr A and Msr B) catalyzes the reduction of methionine sulfoxide to methionine within proteins and its activity and the expression of Msr A have been shown to decline in different organs of aged rats [ ] and more recently in senescent human fibroblasts. Moreover, we have recently shown that the peptide methionine sulfoxide reductase Msr A is present both in the cytosol and in the mitochondrial matrix, although under different isoforms [ ]. In conclusion, during aging or in certain oxidative stress situations, impairment of both peptide methionine sulfoxide reductases and proteasome activity appears as a critical factor in the decreased efficacy of intracellular protein maintenance, contributing to the increased intracellular load of modified and functionally impaired proteins that may ultimately lead to a global deterioration of cellular homeostasis. [ABSTRACT FROM AUTHOR]

Oxidative stress is a cellular disorder implicated in various severe diseases and redox biology and represents an important field of research for the last decades. One of the major consequences of oxidative stress is the carbonylation of proteins, which is also a reliable marker to assess protein oxidative modifications. Accumulation of carbonylated proteins has been associated with aging and age-related diseases and can ultimately causes cell death. Detection of these oxidative modifications is essential to understand and discover new treatments against oxidative stress. We describe the design and the synthetic pathway of new BODIPY fluorescent probes functionalized with hydrazide function for protein carbonyl labeling to improve existing methodologies such as 2D-Oxi electrophoresis. Hydrazide BODIPY analogues show very good fluorescent properties such as NIR emission up to 633 nm and quantum yield up to 0.88. These new probes were validated for the detection and quantification of carbonylated proteins with 2D-Oxi electrophoresis using mouse muscle protein extracts, as well as both flow cytometry and microscopy using oxidant stressed C2 C12 cells., (© 2024 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

Cellular senescence affects many physiological and pathological processes and is characterized by durable cell cycle arrest, an inflammatory secretory phenotype and metabolic reprogramming. Here, by using dynamic transcriptome and metabolome profiling in human fibroblasts with different subtypes of senescence, we show that a homoeostatic switch that results in glycerol-3-phosphate (G3P) and phosphoethanolamine (pEtN) accumulation links lipid metabolism to the senescence gene expression programme. Mechanistically, p53-dependent glycerol kinase activation and post-translational inactivation of phosphate cytidylyltransferase 2, ethanolamine regulate this metabolic switch, which promotes triglyceride accumulation in lipid droplets and induces the senescence gene expression programme. Conversely, G3P phosphatase and ethanolamine-phosphate phospho-lyase-based scavenging of G3P and pEtN acts in a senomorphic way by reducing G3P and pEtN accumulation. Collectively, our study ties G3P and pEtN accumulation to controlling lipid droplet biogenesis and phospholipid flux in senescent cells, providing a potential therapeutic avenue for targeting senescence and related pathophysiology., (© 2024. The Author(s).)

Myocardial infarction (MI) is characterized by a significant loss of cardiomyocytes (CMs), and it is suggested that reactive oxygen species (ROS) are involved in cell cycle arrest, leading to impaired CM renewal. Thioredoxin-1 (Trx-1) scavenges ROS and may play a role in restoring CM renewal. However, the truncated form of Trx-1, Trx-80, can compromise its efficacy by exerting antagonistic effects. Therefore, a Trx-1 mimetic peptide called CB3 was tested as an alternative way to restore CMs. This study aimed to investigate the effects of Trx-1, Trx-80, and CB3 on mice with experimental MI and study the underlying mechanism of CB3 on CMs. Mouse cardiac parameters were quantified by echocardiography, and infarction size and fibrosis determined using Trichrome and Picro-Sirius Red staining. The study found that Trx-1 and CB3 improved mouse cardiac function, reduced the size of cardiac infarct and fibrosis, and decreased the expression of cardiac inflammatory markers. Furthermore, CB3 polarized macrophages into M2 phenotype, reduced apoptosis and oxidative stress after MI, and increased CM proliferation in cell culture and in vivo. CB3 effectively protected against myocardial infarction and could represent a new class of compounds for treating MI., (© 2023 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Senescence is a well-characterized cellular state associated with specific markers such as permanent cell proliferation arrest and the secretion of messenger molecules by cells expressing the senescence-associated secretory phenotype. The senescence-associated secretory phenotype composition depends on many factors such as the cell type or the nature of the stress that induces senescence. Because the skin constitutes a barrier with the external environment, it is particularly subjected to different types of stresses and consequently prone to premature cellular aging. The dicarbonyl compounds glyoxal (GO) and methylglyoxal are precursors of advanced glycation end products, whose presence marks normal and pathological aging. In this study, we show that GO treatment provokes oxidative stress by increasing ROS and advanced glycation end-products levels and induces senescence in human keratinocytes. Furthermore, GO-induced senescence bears a unique molecular progression profile: an early-stage senescence when protein kinase B‒FOXO3a-p27 KIP1 pathway mediates cell cycle arrest and a late-stage senescence maintained by the p16 INK4 /pRb pathway. Moreover, we characterized the resulting secretory phenotype during early-stage senescence by mass spectrometry. Our study provides evidence that GO can affect keratinocyte functions and act as a driver of human skin aging. Hence, senotherapeutics aimed at modulating GO-associated senescence phenotype hold promising potential., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)