Snapshots of cellular advanced glycation end products (AGE) formation
Ontology highlight
ABSTRACT: Quantitative profiling of AGEs in cells were carried out to characterize each AGE formation in cellular proteome after methylgloxal exposure.
Project description:Ossification of the posterior longitudinal ligament (OPLL) is formed by heterogeneous ossification of posterior longitudinal ligament. The patho-mechanism of OPLL is still largely unknown. Recently, disorders of metabolism are thought to be the center of many diseases such as OPLL. Advanced glycation end product (AGE) are accumulated in many extracellular matrixes such as ligament fibers, and it can functions as cellular signal through its receptor (RAGE), contributing to various events such as atherosclerosis or oxidative stress. However, its role in OPLL formation is not yet known. Therefore, we performed high-through-put RNA sequencing on primary posterior longitudinal ligament cells treated with different doses of AGEs (1µM, 5µM and negative control), with or without BMP2 (1µM). mRNA profiles of Primary human posterior longitudinal ligament cells stimulated with various stimuli (Control, 1µM AGE-BSA, 5µM AGE-BSA, 1µM AGE-BSA with BMP2, 5µM AGE-BSA with BMP2) were generated by deep sequencing on Ion Proton
Project description:Advanced glycation end products (AGEs) are formed during the thermal processing of food and have been implicated in the pathogenesis of a series of chronic inflammatory diseases. AGEs are hypothesized to interact with the intestinal epithelium upon the ingestion of thermally processed food, however, their direct effect on intestinal epithelial cells is poorly understood. This study investigates transcriptomic changes in human intestinal epithelial FHs 74 Int cells after exposure to methylglyoxal-modified human serum protein (AGE-HS), S100A12, a known RAGE ligand, and unmodified human serum proteins (HS) in comparison to PBS treated cells. Surprisingly, AGE-HS treatment did not result in significant differential gene expression at standard analysis thresholds, while unmodified HS induced minor transcriptional changes. S100A12 also elicited no significant gene expression alterations. However, GSEA revealed subtle but coordinated changes – AGE-HS treatment induced downregulation of gene sets linked to MYC, interferon responses, and oxidative phosphorylation, paralleling some effects observed with S100A12. Also, KEGG pathway analysis revealed partial overlap between responses to AGE-HS and S100A12 affecting pathways associated with oxidative phosphorylation and neurodegenerative diseases such as Alzheimer, Parkinson, and Huntington disease. This study provides the first global transcriptomic analysis of intestinal epithelial cells treated with AGE-modified proteins. The effects were less pronounced than expected, thus, these data challenge previous reports of robust AGE-induced inflammatory and proliferative effects and emphasize the importance of rigorous endotoxin testing and the use of appropriate controls.
Project description:Ossification of the posterior longitudinal ligament (OPLL) is formed by heterogeneous ossification of posterior longitudinal ligament. The patho-mechanism of OPLL is still largely unknown. Recently, disorders of metabolism are thought to be the center of many diseases such as OPLL. Advanced glycation end product (AGE) are accumulated in many extracellular matrixes such as ligament fibers, and it can functions as cellular signal through its receptor (RAGE), contributing to various events such as atherosclerosis or oxidative stress. However, its role in OPLL formation is not yet known. Therefore, we performed high-through-put RNA sequencing on primary posterior longitudinal ligament cells treated with different doses of AGEs (1µM, 5µM and negative control), with or without BMP2 (1µM).
Project description:Glycation is a post-translational modification underlied by the interaction of protein amino and guanidino groups with carbonyl compounds like reducing sugars and α-dicarbonyls. In the first steps of this process, the protein amino groups react with reducing carbohydrates yielding the corresponding keto- and aldimines, i.e. Amadori and Heyns compounds, respectively. Further degradation of these products results in the formation of advanced glycation end products (AGEs). Alternatively, some representatives of this heterogeneous compound group can originate from α-dicarbonyl products of monosaccharide autoxidation or primary cellular metabolism. In mammals, AGEs are continuously formed during the life of the organism, and accumulate in the tissues, being well-known markers of ageing and impacting age-related stiffing of tissues, decrease of muscle performance, and atherosclerotic changes. However, although the role of AGEs in the ageing of animal tissues is well-studied, their impact in the age-related molecular alterations in plants is completely unknown. To fill this gap, we present here a comprehensive study of the age-related changes in the plant glycated proteome in terms of affected proteins and individual glycation sites therein. Thereby, we consider the qualitative and quantitative changes in glycation patterns in terms of the general metabolic background, pathways of AGE formation, and the status of plant anti-oxidative/anti-glycative defense. Although the patterns of glycated proteins were only minimally influenced by plant age, the abundances of 96 advanced glycation sites in 71 proteins were significantly affected in an age-dependent manner and clearly indicate the existence of glycation hotspots in the plant proteome, the nature of which is discussed here in the sense of structural considerations.
Project description:Staphylococcus aureus (S. aureus) is well known for its biofilm formation ability and is responsible for serious, chronic refractory infections worldwide. We previously demonstrated that advanced glycation end products (AGEs), a hallmark of chronic hyperglycemia in diabetic tissues, enhanced biofilm formation by promoting eDNA release via sigB upregulation in S. aureus, contributing to the high morbidity and mortality of diabetic foot ulcer infection. However, the exact regulatory network has not been completely described. Here, we used a pull-down assay and LC‒MS/MS to identify the GlmS protein as a candidate regulator of sigB in S. aureus stimulated by AGEs. Dual-luciferase assays and electrophoretic mobility shift assays (EMSAs) revealed that GlmS directly upregulated the transcriptional activity of sigB. We constructed Newman ∆glmS for further validation. Quantitative RT‒PCR analysis revealed that AGEs promoted both glmS and sigB expression in the Newman strain but had no effect on Newman ∆glmS. Newman ∆glmS showed a significant attenuation in biofilm formation ability and virulence, accompanied by a decrease in sigB expression, even under AGE stimulation. All of the changes, including pigment deficiency, decreased hemolysis ability, downregulation of hla and hld expression, and less and sparser biofilms, indicated that sigB and biofilm formation ability no longer responded to AGEs in Newman ∆glmS. Our data extend the understanding of GlmS in the global regulatory network of S. aureus and demonstrate a new mechanism by which AGEs can upregulate GlmS, which subsequently directly regulates sigB and plays a significant role in mediating biofilm formation and virulence factor expression.
Project description:Tendon pathologies affect a large portion of people with diabetes. This high rate of tendon pain, injury, and disease appears to manifest independent of well-controlled HbA1c and fasting blood glucose. Advanced glycation end products (AGEs) are elevated in the serum of those with diabetes. In vitro, AGEs severely impact tendon fibroblast proliferation and mitochondrial function. However, the extent that AGEs impact the tendon cell transcriptome has not been evaluated. The purpose of this study was to investigate transcriptome-wide changes that occur to tendon-derived fibroblasts following treatment with AGEs. We propose to complete a descriptive approach to pathway profiling to broaden our mechanistic understanding of cell signaling events that may contribute to the development of tendon pathology. Rat Achilles tendon fibroblasts were treated with glycolaldehyde-derived AGEs (200μg/ml) for 48 hours in normal glucose (5.5mM) conditions. In addition, total RNA was isolated, and the PolyA+ library was sequenced. We demonstrate that tendon fibroblasts treated with 200μg/ml of AGEs differentially express 2,159 gene targets compared to fibroblasts treated with an equal amount of BSA-Control. Additionally, we report in a descriptive and ranked fashion 21 implicated cell-signaling pathways. We demonstrate that tendon fibroblasts treated with 200μg/ml of AGEs differentially express 2,159 gene targets compared to fibroblasts treated with an equal amount of BSA-Control. Additionally, we report in a descriptive and ranked fashion 21 implicated cell-signaling pathways. Our findings suggest that AGEs disrupt the tendon fibroblast transcriptome on a large scale and that these pathways may contribute to the development and progression of diabetic tendinopathy. Specifically, pathways related to cell cycle progression and extracellular matrix remodeling were affected in our data set and may play a contributing role in the development of diabetic tendon complications.
Project description:We studied genome-wide miRNA expression in THP-1 cells treated with/without AGEs. Significant upregulation of miR-214 was observed in THP-1 cells treated with/without AGEs. Two samples, one treated with AGE-BSA and one without AGEs.
Project description:Thermal treatments used in Ultra-Processed Foods (UPFs) lead to advanced glycation end products (AGEs) in food products. UPFs and serum AGEs are both associated with cardiometabolic disease. We explored differential cooking methods as a mechanistic link between UPFs and detrimental health outcomes. We performed a randomized cross-over cooking method trial in healthy subjects provided with identical ingredients.
Project description:Glycative stress, caused by the accumulation of cytotoxic and irreversibly-formed sugar-derived advanced glycation end-products (AGEs), contributes to morbidity associated with aging, age-related diseases, and metabolic diseases. In this review, we summarize pathways leading to formation of AGEs, largely from sugars and glycolytic intermediates, and discuss detoxification of AGE precursors, including the glyoxalase system and DJ-1/Park7 deglycase. Disease pathogenesis downstream of AGE accumulation can be cell autonomous due to aggregation of glycated proteins and impaired protein function, which occurs in ocular cataracts. Extracellular AGEs also activate RAGE signaling, leading to oxidative stress, inflammation, and leukostasis in diabetic complications such as diabetic retinopathy. Pharmaceutical agents have been tested in animal models and clinically to diminish glycative burden. We summarize existing strategies and point out several new directions to diminish glycative stress including: plant-derived polyphenols as AGE inhibitors and glyoxalase inducers; improved dietary patterns, particularly Mediterranean and low glycemic diets; and enhancing proteolytic capacities of the ubiquitin-proteasome and autophagy pathways that are involved in cellular clearing of AGEs.
Project description:Methylglyoxal (MG) is a toxic byproduct of the glycolytic pathway and is quantitatively the most important precursor to advanced glycation end-products (AGEs). Insight into which proteins and in particular their individual modification sites are central to understand the involvement of MG and AGE in diabetes and aging related diseases. Here, we present a method to simultaneously monitor protein AGE formation in biological samples by employing an alkyne-labeled methylglyoxal probe. We apply the method to blood and plasma to demonstrate the impact of blood cell glyoxalase activity on plasma protein AGE formation. We move on to isolate proteins modified by the MG probe and accordingly can present the first general inventory of more than 100 proteins and 300 binding sites of the methylglyoxal probe on plasma as well as erythrocytic proteins.