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Sample records for advanced glycosylation end-products

  1. Cloning and expression of a cell surface receptor for advanced glycosylation end products of proteins.

    PubMed

    Neeper, M; Schmidt, A M; Brett, J; Yan, S D; Wang, F; Pan, Y C; Elliston, K; Stern, D; Shaw, A

    1992-07-25

    Advanced glycosylation end products of proteins (AGEs) are nonenzymatically glycosylated proteins which accumulate in vascular tissue in aging and at an accelerated rate in diabetes. A approximately 35-kDa polypeptide with a unique NH2-terminal sequence has been isolated from bovine lung and found to be present on the surface of endothelial cells where it mediates the binding of AGEs (receptor for advanced glycosylation end product or RAGE). Using an oligonucleotide probe based on the amino-terminal sequence of RAGE, an apparently full-length cDNA of 1.5 kilobases was isolated from a bovine lung cDNA library. This cDNA encoded a 394 amino acid mature protein comprised of the following putative domains: an extracellular domain of 332 amino acids, a single hydrophobic membrane spanning domain of 19 amino acids, and a carboxyl-terminal domain of 43 amino acids. A partial clone encoding the human counterpart of RAGE, isolated from a human lung library, was found to be approximately 90% homologous to the bovine molecule. Based on computer analysis of the amino acid sequence of RAGE and comparison with databases, RAGE is a new member of the immunoglobulin superfamily of cell surface molecules and shares significant homology with MUC 18, NCAM, and the cytoplasmic domain of CD20. Expression of the RAGE cDNA in 293 cells allowed them to bind 125I-AGE-albumin in a saturable and dose-dependent manner (Kd approximately 100 nM), blocked by antibody to RAGE. Western blots of 293 cells transfected with RAGE cDNA probed with anti-RAGE IgG demonstrated expression of immunoreactive protein compared to its absence in mock-transfected cells. These results suggest that RAGE functions as a cell surface receptor for AGEs, which could potentially mediate cellular effects of this class of glycosylated proteins. PMID:1378843

  2. Macrophage recognition of toxic advanced glycosylation end products through the macrophage surface-receptor nucleolin.

    PubMed

    Miki, Yuichi; Dambara, Hikaru; Tachibana, Yoshihiro; Hirano, Kazuya; Konishi, Mio; Beppu, Masatoshi

    2014-01-01

    Advanced glycosylation end-products (AGEs) are non-enzymatically glycosylated proteins that play an important role in several diseases and aging processes, including angiopathy, renal failure, diabetic complications, and some neurodegenerative diseases. In particular, glyceraldehyde (GCA)- and glycolaldehyde (GOA)-derived AGEs are deemed toxic AGEs, due to their cytotoxicity. Recently, the shuttling-protein nucleolin has been shown to possess scavenger receptor-activity. Here, we investigated whether or not macrophages recognize toxic AGEs through nucleolin receptors expressed on their surface. Free amino acid groups and arginine residues found in bovine serum albumin (BSA) were time-dependently modified by incubation with GCA and GOA. In addition, average molecular size was increased by incubation with GCA and GOA. While GCA-treated BSA (GCA-BSA) and GOA-treated BSA (GOA-BSA) were recognized by thioglycollate-elicited mouse peritoneal macrophages in proportion to their respective aldehyde-modification ratios, aldehyde-untreated control-BSA was not. Surface plasmon-resonance analysis revealed that nucleolin strongly associated with GCA-BSA and GOA-BSA, but not with control-BSA. Further, pretreating macrophages with anti-nucleolin antibody, but not control-Immunoglobulin G, inhibited recognition of GCA-BSA and GOA-BSA by macrophages. Additionally, AGRO, a nucleolin-specific oligonucleotide aptamer, inhibited recognition of GCA-BSA and GOA-BSA. Moreover, nucleolin-transfected HEK293 cells recognized more GCA-BSA and GOA-BSA than control HEK cells did. Binding of nucleolin and GCA-BSA/GOA-BSA was also blocked by anti-nucleolin antibody at molecular level. These results indicate that nucleolin is a receptor that allows macrophages to recognize toxic AGEs. PMID:24818254

  3. Effects of bicarbonate/lactate solution on peritoneal advanced glycosylation end-product accumulation.

    PubMed

    Park, M S; Kim, J K; Holmes, C; Weiss, M F

    2000-01-01

    Advanced glycosylation end-products (AGEs) are associated with diabetic complications and peritoneal damage after long-term peritoneal dialysis (PD) with high glucose dialysis solutions. Glucose degradation products (GDPs) derived during heat sterilization of high glucose dialysis solutions are thought to accelerate AGE formation. A new technique of separating glucose from electrolytes has yielded markedly lower GDP levels and permitted the use of dialysis solutions containing the physiologic buffer bicarbonate. Formation of AGEs in vitro with this new solution is significantly lower compared with formation of AGEs with conventional solutions. The purpose of the present study was to investigate the effect of long-term intraperitoneal use of new, neutral dialysis solution (B/L) containing bicarbonate (25 mmol/L) and lactate (15 mmol/L) on peritoneal AGE accumulation and permeability. Normal male Sprague-Dawley rats were used. Twice daily for 12 weeks, 30 mL of new solution (B/L) or conventional solution [Lac (lactate 40 mmol/L)] was injected into the peritoneal cavity of the test rats. As a control, rats that were not injected were kept for 12 weeks in the same manner as the test rats. After 12 weeks, a 2-hour peritoneal equilibration test (PET) was performed in the test rats. After the PET, the parietal peritoneum and liver were obtained for evaluation of peritoneal morphology and for immunohistochemistry for AGE. Intensity of AGE staining was semi-quantitatively graded from 0 to 3. The omentum was also obtained and immediately frozen for analysis of pentosidine content by high-performance liquid chromatography. Compared with findings in the control group, hematoxylin and eosin staining of the parietal peritoneum and liver samples revealed partial denudation of mesothelial cells in the Lac group; denudation was not remarkable in the B/L group. The B/L solution showed significantly less AGE staining in the peritoneal cavity compared to conventional solution. However

  4. Association between the Advanced Glycosylation End Product-Specific Receptor Gene and Cardiovascular Death in Older Men

    PubMed Central

    Biros, Erik; Moran, Corey S.; Norman, Paul E.; Hankey, Graeme J.; Yeap, Bu B.; Almeida, Osvaldo P.; Flicker, Leon; White, Richard; Jones, Rhondda; Golledge, Jonathan

    2015-01-01

    Advanced glycosylation end product-specific receptor (AGER) signaling has been implicated in atherosclerosis. The aim of this study was to evaluate whether a common genetic variation in the AGER gene is associated with cardiovascular (CV) death. We included 1304 older men who were genotyped for rs1035798:C>T, which is a single nucleotide polymorphism (SNP) mapped to the third intron of AGER. Cox proportional hazard analysis was used to estimate the association of rs1035798:C>T with CV death. In addition we analyzed total RNA extracted from carotid atherosclerosis biopsies of 18 patients that did or did not have recent symptoms of cerebral embolization by quantitative real-time reverse transcription PCR (qRT-PCR). The minor T-allele of rs1035798:C>T was found to be associated with CV death under dominant (HR = 1.43, 95% CI: 1.01–2.02, P = 0.04) and recessive (HR = 2.05, 95% CI: 1.11–3.81, P = 0.02) models of inheritance even after adjustment for traditional cardiovascular risk factors. No association was found between rs1035798:C>T and non-CV death. qRT-PCR results suggested that median relative expression of AGER isoform 1 and isoform 6 transcripts were approximately 6- (P = 0.01) and 2-fold (P = 0.02) greater, respectively, within carotid biopsies of symptomatic compared to asymptomatic patients. These data suggest that the minor (T) allele of rs1035798:C>T represents an independent susceptibility factor for CV death. The expression of AGER isoforms is different in atheroma from patients with recent symptoms. Further studies are needed to investigate if rs1035798:C>T influences the alternative splicing of AGER. PMID:26226616

  5. Sequencing of two alternatively spliced mRNAs corresponding to the extracellular domain of the rat receptor for advanced glycosylation end products (RAGE).

    PubMed

    Girón, M D; Vargas, A M; Suárez, M D; Salto, R

    1998-10-01

    The receptor for advanced glycosylation end products (RAGE) is an integral membrane protein responsible for the recognition and internalization of those extensively modified proteins. The receptor has an extracellular domain that binds to the advanced glycosylation end products. By reverse-transcription and polymerase chain reaction amplification, we have identified in rat liver and kidney two amplified products that correspond to cDNA coding for a part of the extracellular domain of the receptor. Sequencing of these products showed that these amplified molecules were similar except for a 27-bp fragment that was absent in the smaller product. This spliced region is located close to the transmembrane region of the receptor. We have confirmed the possibility of the alternative splicing in the generation of these mRNA isoforms by cloning a fragment of the rat gene for RAGE. This fragment has a distribution of introns and exons fully compatible with the proposed alternative splicing. PMID:9790936

  6. Advanced glycation end products

    PubMed Central

    Gkogkolou, Paraskevi; Böhm, Markus

    2012-01-01

    Aging is the progressive accumulation of damage to an organism over time leading to disease and death. Aging research has been very intensive in the last years aiming at characterizing the pathophysiology of aging and finding possibilities to fight age-related diseases. Various theories of aging have been proposed. In the last years advanced glycation end products (AGEs) have received particular attention in this context. AGEs are formed in high amounts in diabetes but also in the physiological organism during aging. They have been etiologically implicated in numerous diabetes- and age-related diseases. Strategies inhibiting AGE accumulation and signaling seem to possess a therapeutic potential in these pathologies. However, still little is known on the precise role of AGEs during skin aging. In this review the existing literature on AGEs and skin aging will be reviewed. In addition, existing and potential anti-AGE strategies that may be beneficial on skin aging will be discussed. PMID:23467327

  7. Localization of the human gene for advanced glycosylation end product-specific receptor (AGER) to chromosome 6p21.3

    SciTech Connect

    Vissing, H.; Aagaard, L.; Boel, E.

    1994-12-01

    Advanced glycosylation end products (AGEs), which are the result of nonenzymatic glycosylation and oxidation of proteins exposed to aldoses, are present in plasma and accumulate in the tissues during aging and at an accelerated rate in diabetes as a result of hyperglycemia. A cell surface receptor for AGE (RAGE) with homology to the immunoglobulin superfamily of receptors has been isolated, and both RAGE antigen and mRNA have been identified in the endothelium, vascular smooth muscle cells, cardiac myocytes, monocyte-derived macrophages, and neural tissue. AGEs modulate a variety of biological reactions in tissues, such as monocyte/macrophage migration and production of cytokine-growth factors in mononuclear cells, as well as permeability, growth, and thrombogenicity of endothelia cells. Although AGEs interact specifically with RAGE, it has been suggested that AGEs are accidental and potentially pathogenic ligands for this receptor. In this study, we have used fluorescence in situ hybridization (FISH) to assign the human RAGE (AGER) gene to chromosome 6p21.3. 9 refs., 1 fig.

  8. Antioxidants inhibit advanced glycosylation end-product-induced apoptosis by downregulation of miR-223 in human adipose tissue-derived stem cells

    PubMed Central

    Wang, Zhe; Li, Hongqiu; Guo, Ran; Wang, Qiushi; Zhang, Dianbao

    2016-01-01

    Advanced glycosylation end products (AGEs) are endogenous inflammatory mediators that induce apoptosis of mesenchymal stem cells. A potential mechanism includes increased generation of reactive oxygen species (ROS). MicroRNA-223 (miR-223) is implicated in the regulation of cell growth and apoptosis in several cell types. Here, we tested the hypothesis that antioxidants N-acetylcysteine (NAC) and ascorbic acid 2-phosphate (AAP) inhibit AGE-induced apoptosis via a microRNA-dependent mechanism in human adipose tissue-derived stem cells (ADSCs). Results showed that AGE-HSA enhanced apoptosis and caspase-3 activity in ADSCs. AGE-HSA also increased ROS generation and upregulated the expression of miR-223. Interestingly, reductions in ROS generation and apoptosis, and upregulation of miR-223 were found in ADSCs treated with antioxidants NAC and AAP. Furthermore, miR-223 mimics blocked antioxidant inhibition of AGE-induced apoptosis and ROS generation. Knockdown of miR-223 amplified the protective effects of antioxidants on apoptosis induced by AGE-HSA. miR-223 acted by targeting fibroblast growth factor receptor 2. These results indicate that NAC and AAP suppress AGE-HSA-induced apoptosis of ADSCs, possibly through downregulation of miR-223. PMID:26964642

  9. Role of advanced glycation end products in cellular signaling☆

    PubMed Central

    Ott, Christiane; Jacobs, Kathleen; Haucke, Elisa; Navarrete Santos, Anne; Grune, Tilman; Simm, Andreas

    2014-01-01

    Improvements in health care and lifestyle have led to an elevated lifespan and increased focus on age-associated diseases, such as neurodegeneration, cardiovascular disease, frailty and arteriosclerosis. In all these chronic diseases protein, lipid or nucleic acid modifications are involved, including cross-linked and non-degradable aggregates, such as advanced glycation end products (AGEs). Formation of endogenous or uptake of dietary AGEs can lead to further protein modifications and activation of several inflammatory signaling pathways. This review will give an overview of the most prominent AGE-mediated signaling cascades, AGE receptor interactions, prevention of AGE formation and the impact of AGEs during pathophysiological processes. PMID:24624331

  10. Vascular Effects of Dietary Advanced Glycation End Products

    PubMed Central

    Stirban, Alin; Tschöpe, Diethelm

    2015-01-01

    Evidence has accumulated lately demonstrating that advanced glycation end products (AGEs) play an important role in the development of diabetic and cardiovascular complications as well as the development of other chronic diseases. AGEs originating from diet have a significant contribution to the AGEs body pool and therefore dietary interventions aiming at reducing AGEs load are believed to exert health promoting effects. This review summarizes the evidence from clinical studies regarding effects of dietary AGEs on the vascular system, highlighting also the different aspects of vascular tests. It also advocates an extension of dietary recommendations towards the promotion of cooking methods that reduce dietary AGEs in consumed foods. PMID:26089897

  11. Sulforaphane inhibits advanced glycation end product-induced pericyte damage by reducing expression of receptor for advanced glycation end products.

    PubMed

    Maeda, Sayaka; Matsui, Takanori; Ojima, Ayako; Takeuchi, Masayoshi; Yamagishi, Sho-Ichi

    2014-09-01

    Advanced glycation end products (AGEs) not only inhibit DNA synthesis but also play a role in diabetic retinopathy by evoking apoptosis and inflammation in retinal pericytes via interaction with a receptor for AGE (RAGE). Similarly, sulforaphane, which is a naturally occurring isothiocyanate that is found in widely consumed cruciferous vegetables, protects against oxidative stress-induced tissue damage. Therefore, we hypothesized that sulforaphane could inhibit AGE-induced pericytes injury through its antioxidative properties. Advanced glycation end product stimulated superoxide generation as well as RAGE gene and protein expression in bovine-cultured retinal pericytes, and these effects were prevented by the treatment with sulforaphane. Antibodies directed against RAGE also blocked AGE-evoked reactive oxygen species generation in pericytes. Sulforaphane and antibodies directed against RAGE significantly inhibited the AGE-induced decrease in DNA synthesis, apoptotic cell death, and up-regulation of monocyte chemoattractant protein 1 messenger RNA levels in pericytes. For the first time, the present study demonstrates that sulforaphane could inhibit DNA synthesis, apoptotic cell death, and inflammatory reactions in AGE-exposed pericytes, partly by suppressing RAGE expression via its antioxidative properties. Blockade of the AGE-RAGE axis in pericytes by sulforaphane might be a novel therapeutic target for the treatment of diabetic retinopathy. PMID:25241332

  12. Advanced glycation end products (AGEs) and diabetic vascular complications.

    PubMed

    Yamagishi, Sho-ichi; Nakamura, Kazuo; Imaizumi, Tsutomu

    2005-02-01

    Diabetic vascular complication is a leading cause of acquired blindness, end-stage renal failure, a variety of neuropathies and accelerated atherosclerosis, which could account for disabilities and high mortality rates in patients with diabetes. Chronic hyperglycemia is essentially involved in the development and progression of diabetic micro- and macroangiopathy. Among various metabolic derangements implicated in the pathogenesis of diabetic vascular complication, advanced glycation end product (AGE) hypothesis is most compatible with the theory of 'hyperglycemic memory'. In this review, we discuss the molecular mechanisms of diabetic vascular complication, specially focusing on AGEs and their receptor (RAGE) system. Several types of AGE inhibitors and their therapeutic implications in this devastating disorder are also discussed here. PMID:18220586

  13. Autofluorescence characterization of advanced glycation end products of hemoglobin

    NASA Astrophysics Data System (ADS)

    Vigneshwaran, Nadanathangam; Bijukumar, Gopalakrishnapillai; Karmakar, Nivedita; Anand, Sneh; Misra, Anoop

    2005-01-01

    This article describes the analysis of autofluorescence of advanced glycation end products of hemoglobin (Hb-AGE). Formed as a result of slow, spontaneous and non-enzymatic glycation reactions, Hb-AGE possesses a characteristic autofluorescence at 308/345 nm ( λex/ λem). Even in the presence of heme as a quenching molecule, the surface presence of the glycated adduct gave rise to autofluorescence with the quantum yield of 0.19. The specificity of monoclonal antibody developed against common AGE structure with Hb-AGE was demonstrated using reduction in fluorescence polarization value due to increased molecular volume while binding. The formation of fluorescent adduct in hemoglobin in the advanced stage of glycation and the non-fluorescent HbA 1c will be of major use in distinguishing and to know the past status of diabetes mellitus. While autofluorescence correlated highly with HbA 1c value under in vivo condition ( r=0.85), it was moderate in the clinical samples ( r=0.55). The results suggest a non-linear relation between glycemia and glycation, indicating the application of Hb-AGE as a measure of susceptibility to glycation rather than glycation itself.

  14. Advanced Glycation End Products, Inflammation, and Chronic Metabolic Diseases: Links in a Chain?

    PubMed

    Davis, Kathleen E; Prasad, Chandan; Vijayagopal, Parakat; Juma, Shanil; Imrhan, Victorine

    2016-01-01

    Advanced glycation end products (AGEs) are a diverse group of compounds produced when reducing sugars react with proteins or other compounds to form glycosylated molecules. AGEs may form endogenously, and glycation of molecules may negatively affect their function. AGEs may also be consumed in food form with dietary AGEs reported to be particularly high in foods treated with high heat: baked, broiled, grilled, and fried foods. Whether dietary AGEs are absorbed in significant quantities and whether they are harmful if absorbed is a question under current debate. The American Diabetes Association makes no recommendation regarding avoidance of these foods, but many researchers are concerned that they may be pro-inflammatory and way worsen cardiac function, kidney function, diabetes and its complications and may even contribute to obesity. PMID:25259686

  15. The road to advanced glycation end products: a mechanistic perspective.

    PubMed

    Cho, S-J; Roman, G; Yeboah, F; Konishi, Y

    2007-01-01

    Protein glycation is a slow natural process involving the chemical modification of the reactive amino and guanidine functions in amino acids by sugars and carbohydrates-derived reactive carbonyls. Its deleterious consequences are obvious in the case of long-lived proteins in aged people and are exacerbated by the high blood concentration of sugars in diabetic patients. The non-enzymatic glycation of proteins occurs through a wide range of concurrent processes comprising condensation, rearrangement, fragmentation, and oxidation reactions. Using a few well established intermediates such as Schiff base, Amadori product and reactive a-dicarbonyls as milestones and the results of in vitro glycation investigations, an overall detailed mechanistic analysis of protein glycation is presented for the first time. The pathways leading to several advanced glycation end products (AGEs) such as (carboxymethyl)lysine, pentosidine, and glucosepane are outlined, whereas other AGEs useful as potential biomarkers of glycation are only briefly mentioned. The current stage of the development of glycation inhibitors has been reviewed with an emphasis on their mechanism of action. PMID:17584071

  16. Advanced Glycation End-Product Accumulation Reduces Vitreous Permeability

    PubMed Central

    Lee, On-Tat; Good, Samuel D.; Lamy, Ricardo; Kudisch, Max; Stewart, Jay M.

    2015-01-01

    Purpose. To evaluate the effect of nonenzymatic cross-linking (glycation) upon the permeability of the vitreous to small- and large-solute diffusion. Methods. Vitreous from freshly excised porcine eyes was treated for 30 minutes with control or 0.01%, 0.1%, or 1% methylglyoxal (MG) solution. The efficacy of the glycation regimen was verified by measuring nonenzymatic cross-link density by fluorescence in the vitreous samples. Resistance to collagenase digestion as well as Nε-(carboxyethyl) lysine (CEL) content were also measured. The permeability coefficient for fluorescein and fluorescein isothiocyanate (FITC)-IgG diffusion through 3 mL of the vitreous samples was determined by using a custom permeability tester. Results. Vitreous cross-linking with MG treatment was confirmed by increased fluorescence, increased CEL concentration, and increased resistance to collagenase digestion. Vitreous glycation resulted in a statistically significant decrease in the permeability coefficient for fluorescein diffusion when either 0.1% or 1% MG solution was used (5.36 ± 5.24 × 10−5 cm s−1, P = 0.04; and 4.03 ± 2.1 × 10−5 cm s−1, P = 0.001; respectively, compared with control, 9.77 ± 5.45 × 10−5 cm s−1). The permeability coefficient for diffusion of FITC-IgG between control (9.9 ± 6.37 × 10−5 cm s−1) and treatment groups was statistically significant at all MG concentrations (0.01% MG: 3.95 ± 3.44 × 10−5 cm s−1, P = 0.003; 0.1% MG: 4.27 ± 1.32 × 10−5 cm s−1, P = 0.004; and 0.1% MG: 3.72 ± 2.49 × 10−5 cm s−1, P = 0.001). Conclusions. Advanced glycation end-product (AGE) accumulation reduces vitreous permeability when glycation is performed in ex vivo porcine vitreous. The permeability change was more pronounced for the larger solute, suggesting a lower threshold for AGE-induced permeability changes to impact the movement of proteins through the vitreous when compared with smaller molecules. PMID:26024075

  17. Lipid advanced glycosylation: pathway for lipid oxidation in vivo.

    PubMed Central

    Bucala, R; Makita, Z; Koschinsky, T; Cerami, A; Vlassara, H

    1993-01-01

    To address potential mechanisms for oxidative modification of lipids in vivo, we investigated the possibility that phospholipids react directly with glucose to form advanced glycosylation end products (AGEs) that then initiate lipid oxidation. Phospholipid-linked AGEs formed readily in vitro, mimicking the absorbance, fluorescence, and immunochemical properties of AGEs that result from advanced glycosylation of proteins. Oxidation of unsaturated fatty acid residues, as assessed by reactive aldehyde formation, occurred at a rate that paralleled the rate of lipid advanced glycosylation. Aminoguanidine, an agent that prevents protein advanced glycosylation, inhibited both lipid advanced glycosylation and oxidative modification. Incubation of low density lipoprotein (LDL) with glucose produced AGE moieties that were attached to both the lipid and the apoprotein components. Oxidized LDL formed concomitantly with AGE-modified LDL. Of significance, AGE ELISA analysis of LDL specimens isolated from diabetic individuals revealed increased levels of both apoprotein- and lipid-linked AGEs when compared to specimens obtained from normal, nondiabetic controls. Circulating levels of oxidized LDL were elevated in diabetic patients and correlated significantly with lipid AGE levels. These data support the concept that AGE oxidation plays an important and perhaps primary role in initiating lipid oxidation in vivo. PMID:8341651

  18. The Mechanisms of Inhibition of Advanced Glycation End Products Formation through Polyphenols in Hyperglycemic Condition.

    PubMed

    Khangholi, Shahpour; Majid, Fadzilah Adibah Abdul; Berwary, Najat Jabbar Ahmed; Ahmad, Farediah; Aziz, Ramlan Bin Abd

    2016-01-01

    Glycation, the non-enzymatic binding of glucose to free amino groups of an amino acid, yields irreversible heterogeneous compounds known as advanced glycation end products. Those products play a significant role in diabetic complications. In the present article we briefly discuss the contribution of advanced glycation end products to the pathogenesis of diabetic complications, such as atherosclerosis, diabetic retinopathy, nephropathy, neuropathy, and wound healing. Then we mention the various mechanisms by which polyphenols inhibit the formation of advanced glycation end products. Finally, recent supporting documents are presented to clarify the inhibitory effects of polyphenols on the formation of advanced glycation end products. Phytochemicals apply several antiglycation mechanisms, including glucose metabolism, amelioration of oxidative stress, scavenging of dicarbonyl species, and up/down-regulation of gene expression. To utilize polyphenols in order to remedy diabetic complications, we must explore, examine and clarify the action mechanisms of the components of polyphenols. PMID:26550791

  19. Advanced glycation end-products: modifiable environmental factors profoundly mediate insulin resistance

    PubMed Central

    Ottum, Mona S.; Mistry, Anahita M.

    2015-01-01

    Advanced glycation end-products are toxic by-products of metabolism and are also acquired from high-temperature processed foods. They promote oxidative damage to proteins, lipids and nucleotides. Aging and chronic diseases are strongly associated with markers for oxidative stress, especially advanced glycation end-products, and resistance to peripheral insulin-mediated glucose uptake. Modifiable environmental factors including high levels of refined and simple carbohydrate diets, hypercaloric diets and sedentary lifestyles drive endogenous formation of advanced glycation end-products via accumulation of highly reactive glycolysis intermediates and activation of the polyol/aldose reductase pathway producing high intracellular fructose. High advanced glycation end-products overwhelm innate defenses of enzymes and receptor-mediated endocytosis and promote cell damage via the pro-inflammatory and pro-oxidant receptor for advanced glycation end-products. Oxidative stress disturbs cell signal transduction, especially insulin-mediated metabolic responses. Here we review emerging evidence that restriction of dietary advanced glycation end-products significantly reduces total systemic load and insulin resistance in animals and humans in diabetes, polycystic ovary syndrome, healthy populations and dementia. Of clinical importance, this insulin sensitizing effect is independent of physical activity, caloric intake and adiposity level. PMID:26236094

  20. N -Glycans on the receptor for advanced glycation end products influence amphoterin binding and neurite outgrowth.

    PubMed

    Srikrishna, Geetha; Huttunen, Henri J; Johansson, Lena; Weigle, Bernd; Yamaguchi, Yu; Rauvala, Heikki; Freeze, Hudson H

    2002-03-01

    In this study we show that embryonic neurite growth-promoting protein amphoterin binds to carboxylated N -glycans previously identified on mammalian endothelial cells. Since amphoterin is a ligand for the receptor for advanced glycation end products (RAGE), and the ligand-binding V-domain of the receptor contains two potential N -glycosylation sites, we hypothesized that N -glycans on RAGE may mediate its interactions with amphoterin. In support of this, anti-carboxylate antibody mAbGB3.1 immunoprecipitates bovine RAGE, and PNGase F treatment reduces its molecular mass by 4.5 kDa, suggesting that the native receptor is a glycoprotein. The binding potential of amphoterin to RAGE decreases significantly in presence of soluble carboxylated glycans or when the receptor is deglycosylated. Oligosaccharide analysis shows that RAGE contains complex type anionic N -glycans with non-sialic acid carboxylate groups, but not the HNK-1 (3-sulfoglucuronyl beta1-3 galactoside) epitope. Consistent with the functional localization of RAGE and amphoterin at the leading edges of developing neurons, mAbGB3.1 stains axons and growth cones of mouse embryonic cortical neurons, and inhibits neurite outgrowth on amphoterin matrix. The carboxylated glycans themselves promote neurite outgrowth in embryonic neurons and RAGE-transfected neuroblastoma cells. This outgrowth requires full-length, signalling-competent RAGE, as cells expressing cytoplasmic domain-deleted RAGE are unresponsive. These results indicate that carboxylated N -glycans on RAGE play an important functional role in amphoterin-RAGE-mediated signalling. PMID:11953450

  1. Chronic diabetes increases advanced glycation end products on cardiac ryanodine receptors/calcium-release channels.

    PubMed

    Bidasee, Keshore R; Nallani, Karuna; Yu, Yongqi; Cocklin, Ross R; Zhang, Yinong; Wang, Mu; Dincer, U Deniz; Besch, Henry R

    2003-07-01

    Decrease in cardiac contractility is a hallmark of chronic diabetes. Previously we showed that this defect results, at least in part, from a dysfunction of the type 2 ryanodine receptor calcium-release channel (RyR2). The mechanism(s) underlying RyR2 dysfunction is not fully understood. The present study was designed to determine whether non-cross-linking advanced glycation end products (AGEs) on RyR2 increase with chronic diabetes and if formation of these post-translational complexes could be attenuated with insulin treatment. Overnight digestion of RyR2 from 8-week control animals (8C) with trypsin afforded 298 peptides with monoisotopic mass (M+H(+)) >or=500. Digestion of RyR2 from 8-week streptozotocin-induced diabetic animals (8D) afforded 21% fewer peptides, whereas RyR2 from 6-week diabetic/2-week insulin-treated animals generated 304 peptides. Using an in-house PERLscript algorithm, search of matrix-assisted laser desorption ionization-time of flight mass data files identified several M+H(+) peaks corresponding to theoretical RyR2 peptides with single N(epsilon)-(carboxymethyl)-lysine, imidazolone A, imidazone B, pyrraline, or 1-alkyl-2-formyl-3,4-glycosyl pyrrole modification that were present in 8D but not 8C. Insulin treatment minimized production of some of these nonenzymatic glycation products. These data show for the first time that AGEs are formed on intracellular RyR2 during diabetes. Because AGE complexes are known to compromise protein activity, these data suggest a potential mechanism for diabetes-induced RyR2 dysfunction. PMID:12829653

  2. Advanced glycation end-products induce heparanase expression in endothelial cells by the receptor for advanced glycation end products and through activation of the FOXO4 transcription factor.

    PubMed

    An, Xiao-Fei; Zhou, Lei; Jiang, Peng-Jun; Yan, Ming; Huang, Yu-Jun; Zhang, Su-Na; Niu, Yun-Fei; Ten, Shi-Chao; Yu, Jiang-Yi

    2011-08-01

    As an endo-β (1-4)-D: -glucuronidase, heparanase can specifically cleave carbohydrate chains of heparan sulfate (HS) and has been implicated in development of endothelial cells dsyfunction. The advanced glycation end products (AGEs) play a pivotal role in the pathology of diabetic complications. In the present study, we investigated the effect of AGE-bovine serum albumin (AGE-BSA) on heparanase expression in human microvascular endothelial cells (HMVECs) and the underlying molecular mechanisms. The results indicated that in vitro direct exposure of HMVECs to AGE-BSA (300, 1000, and 3000 μg/ml) could increase heparanase mRNA and protein expression in a dose and time-dependent manner. The effect of 1000 μg/ml AGE-BSA could be abolished by neutralization with antibody of the receptor for advanced glycation end products (RAGE). Moreover, pretreatment with inhibitors of nuclear factor-κB (NF-κB) or PI3-kinase did not affect heparanase expression induced by AGE-BSA. Nevertheless, small interference RNA (siRNA) for transcriptional factor FOXO4 could reduce the increase of heparanase expression in HMVECs induced by 1000 μg/ml AGE-BSA. These results suggest that AGEs could induce heparanase expression in HMVECs by RAGE and predominantly through activation of the FOXO4 transcription factor. PMID:21461610

  3. Receptor for Advanced Glycation End Products (RAGE) in Type 1 Diabetes Pathogenesis.

    PubMed

    Leung, Sherman S; Forbes, Josephine M; Borg, Danielle J

    2016-10-01

    The receptor for advanced glycation end products (RAGE) is a novel protein increasingly studied in the pathogenesis of type 1 diabetes (T1D). RAGE is expressed by several immune cell types, including T cells, antigen-presenting cells, endothelial cells, and the endocrine cells of the pancreatic islets. RAGE binds various ligands including advanced glycation end products (AGEs), high-mobility group box protein 1 (HMGB1), S100 proteins, β-amyloid, β-sheet fibrils, and lipopolysaccharide. AGEs are a particularly interesting ligand because their exogenous introduction into the body can be accelerated by the consumption of AGE-rich processed foods. This review will detail RAGE isoforms and its ligands and discuss how RAGE binding on the aforementioned cells could be linked to T1D pathogenesis. PMID:27612847

  4. Pyrazole-5-carboxamides, novel inhibitors of receptor for advanced glycation end products (RAGE).

    PubMed

    Han, Young Taek; Kim, Kyeojin; Choi, Gyeong-In; An, Hongchan; Son, Dohyun; Kim, Hee; Ha, Hee-Jin; Son, Jun-Hyeng; Chung, Suk-Jae; Park, Hyun-Ju; Lee, Jeewoo; Suh, Young-Ger

    2014-05-22

    In an effort to develop novel inhibitors of receptor for advanced glycation end products (RAGE) for the treatment of Alzheimer's disease, a series of pyrazole-5-carboxamides were designed, synthesized and biologically evaluated. Analyses of the extensive structure-activity relationship (SAR) led us to identify a 4-fluorophenoxy analog (40) that exhibited improved in vitro RAGE inhibitory activity and more favorable aqueous solubility than the parent 2-aminopyrimidine, 1. Surface plasmon resonance (SPR) and molecular docking study strongly supported the RAGE inhibitory activity of pyrazole-5-carboxamides. The brain Aβ-lowering effect of 40 is also described. PMID:24727489

  5. Inhibition and breaking of advanced glycation end-products (AGEs) with bis-2-aminoimidazole derivatives

    PubMed Central

    Richardson, Mike A.; Furlani, Robert E.; Podell, Brendan K.; Ackart, David F.; Haugen, Jessica D.; Melander, Roberta J.; Melander, Christian; Basaraba, Randall J.

    2015-01-01

    Advanced glycation end-products (AGEs), unregulated modifications to host macromolecules that occur as a result of metabolic dysregulation, play a role in many diabetes related complications, inflammation and aging, and may lead to increased cardiovascular risk. Small molecules that have the ability to inhibit AGE formation, and even break preformed AGEs have enormous therapeutic potential in the treatment of these disease states. We report the screening of a series of 2-aminoimidazloles for anti-AGE activity, and the identification of a bis-2-aminoimidazole lead compound that possesses superior AGE inhibition and breaking activity compared to the known AGE inhibitor aminoguanidine. PMID:26146419

  6. Relationship of Advanced Glycation End Products With Cardiovascular Disease in Menopausal Women.

    PubMed

    Pertynska-Marczewska, Magdalena; Merhi, Zaher

    2015-07-01

    Cardiovascular disease (CVD) represents the most significant cause of death in postmenopausal women. Advanced glycation end products (AGEs) are formed by nonenzymatic modification of proteins, lipids, and nucleic acids by glucose. This review focuses on the contribution of AGEs and their receptors to the development of CVD in menopause. Advanced glycation end products circulate and activate the proinflammatory endothelial cell surface receptor called RAGE, bind to the extracellular matrix of the cardiovascular system, or bind to the circulating anti-inflammatory soluble form of RAGE (sRAGE). Data emerging from human and animal studies suggest that AGEs and both receptors (RAGE and sRAGE) are implicated in the pathophysiology of CVD. Particular emphasis has been given to the role of AGE-RAGE axis in oxidative stress, inflammation, endothelial cell toxicity, and progression of atherosclerosis in menopause. Data accruing from human and animal studies suggest that RAGE expression level and circulating sRAGE level are associated with estradiol and are correlated with CVD risk factors, such as adiposity, dyslipidemia, insulin resistance, diabetes, and metabolic syndrome. By recognizing the impact of AGEs on atherosclerosis, pharmacological strategies targeting the AGE-RAGE pathway hold therapeutic potential for CVD in menopausal women. PMID:25228634

  7. Soluble receptor for advanced glycation end products: from disease marker to potential therapeutic target.

    PubMed

    Geroldi, Diego; Falcone, Colomba; Emanuele, Enzo

    2006-01-01

    The receptor for advanced glycation end products (RAGE) is a cell-bound receptor of the immunoglobulin superfamily which may be activated by a variety of proinflammatory ligands including advanced glycoxidation end products, S100/calgranulins, high mobility group box 1, and amyloid beta-peptide. RAGE has a secretory splice isoform, soluble RAGE (sRAGE), that lacks the transmembrane domain and therefore circulates in plasma. By competing with cell-surface RAGE for ligand binding, sRAGE may contribute to the removal/neutralization of circulating ligands thus functioning as a decoy. Clinical studies have recently shown that higher plasma levels of sRAGE are associated with a reduced risk of coronary artery disease, hypertension, the metabolic syndrome, arthritis and Alzheimer's disease. Increasing the production of plasma sRAGE is therefore considered to be a promising therapeutic target that has the potential to prevent vascular damage and neurodegeneration. This review presents the state of the art in the use of sRAGE as a disease marker and discusses the therapeutic potential of targeting sRAGE for the treatment of inflammation-related diseases such as atherosclerosis, arthritis and Alzheimer's disease. PMID:16842191

  8. Receptor for Advanced Glycation End Products and its Inflammatory Ligands are Upregulated in Amyotrophic Lateral Sclerosis

    PubMed Central

    Juranek, Judyta K.; Daffu, Gurdip K.; Wojtkiewicz, Joanna; Lacomis, David; Kofler, Julia; Schmidt, Ann Marie

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder of largely unknown pathogenesis. Recent studies suggest that enhanced oxidative stress and neuroinflammation contribute to the progression of the disease. Mounting evidence implicates the receptor for advanced glycation end-products (RAGE) as a significant contributor to the pathogenesis of certain neurodegenerative diseases and chronic conditions. It is hypothesized that detrimental actions of RAGE are triggered upon binding to its ligands, such as AGEs (advanced glycation end products), S100/calgranulin family members, and High Mobility Group Box-1 (HMGB1) proteins. Here, we examined the expression of RAGE and its ligands in human ALS spinal cord. Tissue samples from age-matched human control and ALS spinal cords were tested for the expression of RAGE, carboxymethyllysine (CML) AGE, S100B, and HMGB1, and intensity of the immunofluorescent and immunoblotting signals was assessed. We found that the expression of both RAGE and its ligands was significantly increased in the spinal cords of ALS patients versus age-matched control subjects. Our study is the first report describing co-expression of both RAGE and its ligands in human ALS spinal cords. These findings suggest that further probing of RAGE as a mechanism of neurodegeneration in human ALS is rational. PMID:26733811

  9. Advanced Glycation End Products in Foods and a Practical Guide to Their Reduction in the Diet

    PubMed Central

    URIBARRI, JAIME; WOODRUFF, SANDRA; GOODMAN, SUSAN; CAI, WEIJING; CHEN, XUE; PYZIK, RENATA; YONG, ANGIE; STRIKER, GARY E.; VLASSARA, HELEN

    2013-01-01

    Modern diets are largely heat-processed and as a result contain high levels of advanced glycation end products (AGEs). Dietary advanced glycation end products (dAGEs) are known to contribute to increased oxidant stress and inflammation, which are linked to the recent epidemics of diabetes and cardiovascular disease. This report significantly expands the available dAGE database, validates the dAGE testing methodology, compares cooking procedures and inhibitory agents on new dAGE formation, and introduces practical approaches for reducing dAGE consumption in daily life. Based on the findings, dry heat promotes new dAGE formation by >10- to 100-fold above the uncooked state across food categories. Animal-derived foods that are high in fat and protein are generally AGE-rich and prone to new AGE formation during cooking. In contrast, carbohydrate-rich foods such as vegetables, fruits, whole grains, and milk contain relatively few AGEs, even after cooking. The formation of new dAGEs during cooking was prevented by the AGE inhibitory compound aminoguanidine and significantly reduced by cooking with moist heat, using shorter cooking times, cooking at lower temperatures, and by use of acidic ingredients such as lemon juice or vinegar. The new dAGE database provides a valuable instrument for estimating dAGE intake and for guiding food choices to reduce dAGE intake. PMID:20497781

  10. Differential effects between amphoterin and advanced glycation end products on colon cancer cells.

    PubMed

    Kuniyasu, Hiroki; Chihara, Yoshitomo; Kondo, Hideaki

    2003-05-10

    Amphoterin is 1 ligand of the receptor for advanced glycation end products (RAGE). We studied expression of amphoterin and RAGE mRNA and proteins in colorectal carcinoma cells and investigated their associations with the invasive activities of cells exposed to advanced glycation end products (AGE). Expression of RAGE and amphoterin was examined in 4 colorectal carcinoma cell lines. All cell lines expressed both RAGE and amphoterin. The effects of RAGE and amphoterin on cell growth (MTT assay), migration (wound healing assay) and invasion (in vitro invasion assay) were tested by treatment of cells with RAGE and amphoterin antisense S-oligodeoxynucleotides (ODNs). Cell growth, migration and invasion were inhibited significantly in Colo320 and WiDr carcinoma cells treated with RAGE and amphoterin antisense S-ODNs compared with sense-treated cells. Differences in ligand activity between amphoterin and AGE were examined with AGE-bovine serum albumin (BSA). AGE-BSA decreased cell growth, migration and invasion of amphoterin antisense S-ODN-treated Colo320 and WiDr cells compared with those of cells treated with Colo320 conditioned medium. Phosphorylation of extracellular signal-regulated kinase-1/2, Rac1 and AKT and production of matrix metalloproteinase 9 were increased to a greater degree by amphoterin than by AGE-BSA. In contrast, production of inducible nitric oxide synthase and nuclear factor-kappaBp65 were increased to a greater degree by AGE-BSA than by amphoterin. PMID:12640679

  11. Advanced glycation end products in foods and a practical guide to their reduction in the diet.

    PubMed

    Uribarri, Jaime; Woodruff, Sandra; Goodman, Susan; Cai, Weijing; Chen, Xue; Pyzik, Renata; Yong, Angie; Striker, Gary E; Vlassara, Helen

    2010-06-01

    Modern diets are largely heat-processed and as a result contain high levels of advanced glycation end products (AGEs). Dietary advanced glycation end products (dAGEs) are known to contribute to increased oxidant stress and inflammation, which are linked to the recent epidemics of diabetes and cardiovascular disease. This report significantly expands the available dAGE database, validates the dAGE testing methodology, compares cooking procedures and inhibitory agents on new dAGE formation, and introduces practical approaches for reducing dAGE consumption in daily life. Based on the findings, dry heat promotes new dAGE formation by >10- to 100-fold above the uncooked state across food categories. Animal-derived foods that are high in fat and protein are generally AGE-rich and prone to new AGE formation during cooking. In contrast, carbohydrate-rich foods such as vegetables, fruits, whole grains, and milk contain relatively few AGEs, even after cooking. The formation of new dAGEs during cooking was prevented by the AGE inhibitory compound aminoguanidine and significantly reduced by cooking with moist heat, using shorter cooking times, cooking at lower temperatures, and by use of acidic ingredients such as lemon juice or vinegar. The new dAGE database provides a valuable instrument for estimating dAGE intake and for guiding food choices to reduce dAGE intake. PMID:20497781

  12. Dietary Advanced Glycation End Products and Their Role in Health and Disease12

    PubMed Central

    Uribarri, Jaime; del Castillo, María Dolores; de la Maza, María Pía; Filip, Rosana; Gugliucci, Alejandro; Luevano-Contreras, Claudia; Macías-Cervantes, Maciste H; Markowicz Bastos, Deborah H; Medrano, Alejandra; Menini, Teresita; Portero-Otin, Manuel; Rojas, Armando; Sampaio, Geni Rodrigues; Wrobel, Kazimierz; Wrobel, Katarzyna; Garay-Sevilla, Ma Eugenia

    2015-01-01

    Over the past 2 decades there has been increasing evidence supporting an important contribution from food-derived advanced glycation end products (AGEs) to the body pool of AGEs and therefore increased oxidative stress and inflammation, processes that play a major role in the causation of chronic diseases. A 3-d symposium (1st Latin American Symposium of AGEs) to discuss this subject took place in Guanajuato, Mexico, on 1–3 October 2014 with the participation of researchers from several countries. This review is a summary of the different presentations and subjects discussed, and it is divided into 4 sections. The first section deals with current general knowledge about AGEs. The second section dwells on mechanisms of action of AGEs, with special emphasis on the receptor for advanced glycation end products and the potential role of AGEs in neurodegenerative diseases. The third section discusses different approaches to decrease the AGE burden. The last section discusses current methodologic problems with measurement of AGEs in different samples. The subject under discussion is complex and extensive and cannot be completely covered in a short review. Therefore, some areas of interest have been left out because of space. However, we hope this review illustrates currently known facts about dietary AGEs as well as pointing out areas that require further research. PMID:26178030

  13. Dietary advanced glycation end products and their role in health and disease.

    PubMed

    Uribarri, Jaime; del Castillo, María Dolores; de la Maza, María Pía; Filip, Rosana; Gugliucci, Alejandro; Luevano-Contreras, Claudia; Macías-Cervantes, Maciste H; Markowicz Bastos, Deborah H; Medrano, Alejandra; Menini, Teresita; Portero-Otin, Manuel; Rojas, Armando; Sampaio, Geni Rodrigues; Wrobel, Kazimierz; Wrobel, Katarzyna; Garay-Sevilla, Ma Eugenia

    2015-07-01

    Over the past 2 decades there has been increasing evidence supporting an important contribution from food-derived advanced glycation end products (AGEs) to the body pool of AGEs and therefore increased oxidative stress and inflammation, processes that play a major role in the causation of chronic diseases. A 3-d symposium (1st Latin American Symposium of AGEs) to discuss this subject took place in Guanajuato, Mexico, on 1-3 October 2014 with the participation of researchers from several countries. This review is a summary of the different presentations and subjects discussed, and it is divided into 4 sections. The first section deals with current general knowledge about AGEs. The second section dwells on mechanisms of action of AGEs, with special emphasis on the receptor for advanced glycation end products and the potential role of AGEs in neurodegenerative diseases. The third section discusses different approaches to decrease the AGE burden. The last section discusses current methodologic problems with measurement of AGEs in different samples. The subject under discussion is complex and extensive and cannot be completely covered in a short review. Therefore, some areas of interest have been left out because of space. However, we hope this review illustrates currently known facts about dietary AGEs as well as pointing out areas that require further research. PMID:26178030

  14. Do advanced glycation end-products play a role in malaria susceptibility?

    PubMed Central

    Traoré, Karim; Arama, Charles; Médebielle, Maurice; Doumbo, Ogobara; Picot, Stéphane

    2016-01-01

    There are growing data supporting the differences in susceptibility to malaria described between sympatric populations with different lifestyles. Evidence has also been growing for some time that nutritional status and the host’s metabolism are part of the complex mechanisms underlying these differences. The role of dietary advanced glycation end-products (AGEs) in the modulation of immune responses (innate and adaptive responses) and chronic oxidative stress has been established. But less is known about AGE implication in naturally acquired immunity and susceptibility to malaria. Since inflammatory immune responses and oxidative events have been demonstrated as the hallmark of malaria infection, it seems crucial to investigate the role of AGE in susceptibility or resistance to malaria. This review provides new insight into the relationship between nutrition, metabolic disorders, and infections, and how this may influence the mechanisms of susceptibility or resistance to malaria in endemic areas. PMID:27012162

  15. [Expression and function of receptors for advanced glycation end products in bovine corneal endothelial cells].

    PubMed

    Kaji, Yuichi

    2005-11-01

    Corneal endothelial cell loss is a change that occurs with age, but its mechanism is still unclear. We postulated that interaction between advanced glycation end product(AGE) and its receptors is implicated in the corneal endothelial cell loss with age. We investigated the expression of AGE receptors: receptors for AGE(RAGE) and galectin-3 in bovine corneal endothelial cells by reverse transcription-polymerase chain reaction(RT-PCR) and immunohistochemistry. In addition, we investigated the effect of AGE on the cultured corneal endothelial cells. Expression of RAGE and galectin-3 was detected in bovine corneal endothelial cells. Galectin-3 was important in the internalization of AGE. In contrast, RAGE was important in the generation of reactive oxygen species and induction of apoptosis. Based on these data, the interaction of AGE in aqueous humor and AGE receptors expressed on the corneal endothelial cells was speculated to have a role in the corneal endothelial cell loss with age. PMID:16363662

  16. Study of an Unusual Advanced Glycation End-Product (AGE) Derived from Glyoxal Using Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Lopez-Clavijo, Andrea F.; Duque-Daza, Carlos A.; Romero Canelon, Isolda; Barrow, Mark P.; Kilgour, David; Rabbani, Naila; Thornalley, Paul J.; O'Connor, Peter B.

    2014-04-01

    Glycation is a post-translational modification (PTM) that affects the physiological properties of peptides and proteins. In particular, during hyperglycaemia, glycation by α-dicarbonyl compounds generate α-dicarbonyl-derived glycation products also called α-dicarbonyl-derived advanced glycation end products. Glycation by the α-dicarbonyl compound known as glyoxal was studied in model peptides by MS/MS using a Fourier transform ion cyclotron resonance mass spectrometer. An unusual type of glyoxal-derived AGE with a mass addition of 21.98436 Da is reported in peptides containing combinations of two arginine-two lysine, and one arginine-three lysine amino acid residues. Electron capture dissociation and collisionally activated dissociation results supported that the unusual glyoxal-derived AGE is formed at the guanidino group of arginine, and a possible structure is proposed to illustrate the 21.9843 Da mass addition.

  17. Advanced glycation end products overload might explain intracellular cobalamin deficiency in renal dysfunction, diabetes and aging.

    PubMed

    Obeid, Rima; Shannan, Batool; Herrmann, Wolfgang

    2011-11-01

    Advanced glycation end products (AGEs) contribute to aging. Cobalamin (Cbl) is required for cell growth and functions, and its deficiency causes serious complications. Diabetics and renal patients show high concentrations of Cbl, but metabolic evidence of Cbl deficiency that is reversible after Cbl treatment. Cbl might be sequestered in blood and cannot be delivered to the cell. Megalin mediates the uptake of transcobalamin-Cbl complex into the proximal tubule cells. Megalin is involved in the uptake and degradation of AGEs. In aging, diabetes or renal dysfunction, AGEs might overload megalin thus lowering Cbl uptake. Transcobalamin-Cbl might retain in blood. Shedding of megalin and transcobalamin receptor under glycation conditions is also a possible mechanism of this phenomenon. PMID:21880434

  18. Advanced glycation end-products: a common pathway in diabetes and age-related erectile dysfunction.

    PubMed

    Neves, D

    2013-08-01

    Reactive derivatives of non-enzymatic glucose-protein condensation reactions integrate a heterogeneous group of irreversible adducts called advanced glycation end-products (AGEs). Numerous studies have investigated the role of the AGEs in cardiovascular system; however, its contribution to erectile dysfunction (ED) that is an early manifestation of cardiovascular disease has been less intensively investigated. This review summarizes the most recent advances concerning AGEs effects in the cavernous tissue of the penis and in ED onset, particularly on diabetes and aging, conditions that not only favor AGEs formation, but also increase risk of developing ED. The specific contribution of AGE on intra- and extracellular deposition of insoluble complexes, interference in activity of endothelial nitric oxide (NO) synthase, NO bioavailability, endothelial-dependent vasodilatation, as well as molecular pathways activated by receptor of AGEs are presented. Finally, the interventional actions that prevent AGEs formation, accumulation or activity in the cavernous tissue and that include nutritional pattern modulation, nutraceuticals, exercise, therapeutic strategies (statins, anti-diabetics, inhibitors of phosphodiesterase-5, anti-hypertensive drugs) and inhibitors of AGEs formation and crosslink breakers, are discussed. From this review, we conclude that despite the experiments conducted in animal models pointing to the AGE/RAGE axis as a potential interventional target with respect to ED associated with diabetes and aging, the clinical data have been very disappointing and, until now, did not provide evidence of benefits of treatments directed to AGE inactivation. PMID:23822116

  19. Development of Nonalcoholic Hepatopathy: Contributions of Oxidative Stress and Advanced Glycation End Products

    PubMed Central

    Santos, Juliana Célia de F.; Valentim, Iara B.; de Araújo, Orlando R. P.; Ataide, Terezinha da R.; Goulart, Marília O. F.

    2013-01-01

    Advanced glycation end products (AGEs) are generated spontaneously in cells; however, under conditions of hyperglycemia and lipid peroxidation, their levels are higher than usual, which contribute to the development of diseases such as the nonalcoholic fatty liver disease (NAFLD). NAFLD is associated with oxidative stress (OS), which is linked to the transition of steatosis to steatohepatitis due to lipid peroxidation. The AGE-receptor interaction in hepatic stellate cells leads to an increase in reactive oxygen species and enhances the proliferation and activation of these cells, worsening liver fibrosis and disease progression. In this vicious cycle, there is production of (carboxymethyl)lysine, a biomarker for products of advanced glycation and lipid peroxidation, being a shared component between the two pathways. In this review, we aim to compile evidence to support the basic molecular mechanisms of AGEs and OS generation and their influence, independently or combined, on the evolution of NAFLD. The deeper understanding of the interrelations of AGEs + OS may help to elucidate the pathogenic pathways of NAFLD and to devise rational therapeutic interventions for this disease, with an expected positive impact on quality of life of patients. PMID:24084729

  20. Advanced glycation end products facilitate bacterial adherence in urinary tract infection in diabetic mice

    PubMed Central

    Ozer, Ahmet; Altuntas, Cengiz Z.; Izgi, Kenan; Bicer, Fuat; Hultgren, Scott J.; Liu, Guiming; Daneshgari, Firouz

    2014-01-01

    Diabetic individuals have increased susceptibility to urinary tract infection (UTI), a common, painful condition. During diabetes mellitus, non-enzymatic reactions between reducing sugars and protein amine groups result in excessive production of advanced glycation end products (AGEs) that accumulate in tissues. Since bacteria adhere to cell surfaces by binding to carbohydrates, we hypothesized that adherence of bacteria to the bladder in diabetics may be enhanced by accumulation of AGEs on urothelial surface proteins. Using a murine model of UTI, we observed increased adherence of type 1 fimbriated uropathogenic Escherichia coli (UPEC) to the bladder in streptozotocin-induced diabetic female mice compared with age-matched controls, along with increased concentrations of two common AGEs in superficial urothelial cells from diabetic bladders. Several lectins with different specificities exhibited increased binding to urothelial homogenates from diabetic mice compared with controls, and two of those lectins also bound to AGEs. Furthermore, mannose-binding type 1 fimbriae isolated from UPEC bound to different AGEs, and UPEC adherence to the bladder in diabetic mice, were inhibited by pretreatment of mice with the AGE inhibitor pyridoxamine. These results strongly suggest a role for urothelial AGE accumulation in increased bacterial adherence during UTI in diabetes. PMID:25986378

  1. Receptor for advanced glycation end products (RAGE) knockout reduces fetal dysmorphogenesis in murine diabetic pregnancy.

    PubMed

    Ejdesjö, Andreas; Brings, Sebastian; Fleming, Thomas; Fred, Rikard G; Nawroth, Peter P; Eriksson, Ulf J

    2016-07-01

    The receptor for Advanced Glycation End products (RAGE) is implicated in the pathogenesis of diabetic complications, but its importance in diabetic embryopathy is unclear. We therefore investigated the role of RAGE in diabetic embryopathy using streptozotocin induced diabetes in female wild type (WT) C57Bl/6N and RAGE knockout C57Bl/6N (RAGE(-/-)) mice, mated with control males of the same genotype. Maternal diabetes induced more fetal resorption and malformation (facial skeleton, neural tube) in the WT than in the RAGE(-/-) fetuses. Maternal plasma glucose and methylgyoxal concentrations, as well as embryonic N(ε)-carboxymethyl-lysine (CML) levels were increased to the same extent in diabetic WT and RAGE(-/-) pregnancy. However, maternal diabetes induced increased fetal hepatic isoprostane 8-iso-PGF2α levels (oxidative stress marker) and embryonic activation of NFκB in WT only (not in RAGE(-/-) embryos). The association between RAGE knockout and diminished embryonic dysmorphogenesis in diabetic pregnancy suggests that embryonic RAGE activation is involved in diabetic embryopathy. PMID:27109771

  2. Advanced Glycation End Products: Link between Diet and Ovulatory Dysfunction in PCOS?

    PubMed Central

    Garg, Deepika; Merhi, Zaher

    2015-01-01

    PCOS is the most common cause of anovulation in reproductive-aged women with 70% experiencing ovulatory problems. Advanced glycation end products are highly reactive molecules that are formed by non-enzymatic reactions of sugars with proteins, nucleic acids and lipids. AGEs are also present in a variety of diet where substantial increase in AGEs can result due to thermal processing and modifications of food. Elevation in bodily AGEs, produced endogenously or absorbed exogenously from high-AGE diets, is further exaggerated in women with PCOS and is associated with ovulatory dysfunction. Additionally, increased expression of AGEs as pro-inflammatory receptors in the ovarian tissue has been observed in women with PCOS. In this review, we summarize the role of dietary AGEs as mediators of metabolic and reproductive alterations in PCOS. Once a mechanistic understanding of the relationship between AGEs and anovulation is established, there is a promise that such knowledge will contribute to the subsequent development of targeted pharmacological therapies that will treat anovulation and improve ovarian health in women with PCOS. PMID:26690206

  3. Statins stimulate the production of a soluble form of the receptor for advanced glycation end products

    PubMed Central

    Quade-Lyssy, Patricia; Kanarek, Anna Maria; Baiersdörfer, Markus; Postina, Rolf; Kojro, Elzbieta

    2013-01-01

    The beneficial effects of statin therapy in the reduction of cardiovascular pathogenesis, atherosclerosis, and diabetic complications are well known. The receptor for advanced glycation end products (RAGE) plays an important role in the progression of these diseases. In contrast, soluble forms of RAGE act as decoys for RAGE ligands and may prevent the development of RAGE-mediated disorders. Soluble forms of RAGE are either produced by alternative splicing [endogenous secretory RAGE (esRAGE)] or by proteolytic shedding mediated by metalloproteinases [shed RAGE (sRAGE)]. Therefore we analyzed whether statins influence the production of soluble RAGE. Lovastatin treatment of either mouse alveolar epithelial cells endogenously expressing RAGE or HEK cells overexpressing RAGE caused induction of RAGE shedding, but did not influence secretion of esRAGE from HEK cells overexpressing esRAGE. Lovastatin-induced secretion of sRAGE was also evident after restoration of the isoprenylation pathway, demonstrating a correlation of sterol biosynthesis and activation of RAGE shedding. Lovastatin-stimulated induction of RAGE shedding was completely abolished by a metalloproteinase ADAM10 inhibitor. We also demonstrate that statins stimulate RAGE shedding at low physiologically relevant concentrations. Our results show that statins, due to their cholesterol-lowering effects, increase the soluble RAGE level by inducing RAGE shedding, and by doing this, might prevent the development of RAGE-mediated pathogenesis. PMID:23966666

  4. Clearance Kinetics and Matrix Binding Partners of the Receptor for Advanced Glycation End Products

    PubMed Central

    Milutinovic, Pavle S.; Englert, Judson M.; Crum, Lauren T.; Mason, Neale S.; Ramsgaard, Lasse; Enghild, Jan J.; Sparvero, Louis J.; Lotze, Michael T.; Oury, Tim D.

    2014-01-01

    Elucidating the sites and mechanisms of sRAGE action in the healthy state is vital to better understand the biological importance of the receptor for advanced glycation end products (RAGE). Previous studies in animal models of disease have demonstrated that exogenous sRAGE has an anti-inflammatory effect, which has been reasoned to arise from sequestration of pro-inflammatory ligands away from membrane-bound RAGE isoforms. We show here that sRAGE exhibits in vitro binding with high affinity and reversibly to extracellular matrix components collagen I, collagen IV, and laminin. Soluble RAGE administered intratracheally, intravenously, or intraperitoneally, does not distribute in a specific fashion to any healthy mouse tissue, suggesting against the existence of accessible sRAGE sinks and receptors in the healthy mouse. Intratracheal administration is the only effective means of delivering exogenous sRAGE to the lung, the organ in which RAGE is most highly expressed; clearance of sRAGE from lung does not differ appreciably from that of albumin. PMID:24642901

  5. Effect of diet-derived advanced glycation end products on inflammation.

    PubMed

    Kellow, Nicole J; Coughlan, Melinda T

    2015-11-01

    Advanced glycation end products (AGEs) formed via the Maillard reaction during the thermal processing of food contributes to the flavor, color, and aroma of food. A proportion of food-derived AGEs and their precursors is intestinally absorbed and accumulates within cells and tissues. AGEs have been implicated in the pathogenesis of diabetes-related complications and several chronic diseases via interaction with the receptor for AGEs, which promotes the transcription of genes that control inflammation. The dicarbonyls, highly reactive intermediates of AGE formation, are also generated during food processing and may incite inflammatory responses through 1) the suppression of protective pathways, 2) the incretin axis, 3) the modulation of immune-mediated signaling, and 4) changes in gut microbiota profile and metabolite sensors. In animal models, restriction of dietary AGEs attenuates chronic low-grade inflammation, but current evidence from human studies is less clear. Here, the emerging relationship between excess dietary AGE consumption and inflammation is explored, the utility of dietary AGE restriction as a therapeutic strategy for the attenuation of chronic diseases is discussed, and possible avenues for future investigation are suggested. PMID:26377870

  6. Hyperglycemia attenuates acute permeability response to advanced glycation end products in retinal microvasculature.

    PubMed

    Warboys, C M; Fraser, P A

    2010-07-01

    Increased microvascular permeability contributes to the development of diabetic retinopathy and is associated with hyperglycemia and accumulation of advanced glycation end products (AGEs). The isolated perfused retina preparation was used to investigate the effects of hyperglycemia (HG) on the permeability response to AGEs. Retinae were dissected from rats, and the vasculature perfused with sulforhodamine B fluorescent dye and permeability of venular capillaries was determined from the rate of decrease of fluorescence gradient across a vessel during stasis. The resting permeability was very high in streptozotocin treated and some obese Zucker fatty diabetic rats, but low in others. The permeability response to glycated albumin (which is free radical-dependent) in these animals was reduced for a range of concentrations compared to the lean controls. The effects of 15 min 25 mM glucose (HG) superfusion on the retinal microvascular permeability response to 5 microM AGE-BSA was studied in non-diabetic Wistar rats. HG itself had no effect on permeability, but reduced the response to AGE-BSA from 1.02+/-0.08x10(-6) cm s(-1) to 0.31+/-0.07x10(-6) cm s(-1). The response to bradykinin (also free radical-dependent) was not affected by HG. This suggests that chronic exposure to HG down-regulates the signalling pathways activated in response to RAGE stimulation. PMID:20302881

  7. Advanced Glycation End Products: A Molecular Target for Vascular Complications in Diabetes

    PubMed Central

    Yamagishi, Sho-ichi; Nakamura, Nobutaka; Suematsu, Mika; Kaseda, Kuniyoshi; Matsui, Takanori

    2015-01-01

    A nonenzymatic reaction between reducing sugars and amino groups of proteins, lipids and nucleic acids contributes to the aging of macromolecules and subsequently alters their structural integrity and function. This process has been known to progress at an accelerated rate under hyperglycemic and/or oxidative stress conditions. Over a course of days to weeks, early glycation products undergo further reactions such as rearrangements and dehydration to become irreversibly cross-linked, fluorescent and senescent macroprotein derivatives termed advanced glycation end products (AGEs). There is a growing body of evidence indicating that interaction of AGEs with their receptor (RAGE) elicits oxidative stress generation and as a result evokes proliferative, inflammatory, thrombotic and fibrotic reactions in a variety of cells. This evidence supports AGEs’ involvement in diabetes- and aging-associated disorders such as diabetic vascular complications, cancer, Alzheimer’s disease and osteoporosis. Therefore, inhibition of AGE formation could be a novel molecular target for organ protection in diabetes. This report summarizes the pathophysiological role of AGEs in vascular complications in diabetes and discusses the potential clinical utility of measurement of serum levels of AGEs for evaluating organ damage in diabetes. PMID:26605646

  8. Longistatin in tick saliva blocks advanced glycation end-product receptor activation

    PubMed Central

    Anisuzzaman; Hatta, Takeshi; Miyoshi, Takeharu; Matsubayashi, Makoto; Islam, M. Khyrul; Alim, M. Abdul; Anas, M. Abu; Hasan, M. Mehedi; Matsumoto, Yasunobu; Yamamoto, Yasuhiko; Yamamoto, Hiroshi; Fujisaki, Kozo; Tsuji, Naotoshi

    2014-01-01

    Ticks are notorious hematophagous ectoparasites and vectors of many deadly pathogens. As an effective vector, ticks must break the strong barrier provided by the skin of their host during feeding, and their saliva contains a complex mixture of bioactive molecules that paralyze host defenses. The receptor for advanced glycation end products (RAGE) mediates immune cell activation at inflammatory sites and is constitutively and highly expressed in skin. Here, we demonstrate that longistatin secreted with saliva of the tick Haemaphysalis longicornis binds RAGE and modulates the host immune response. Similar to other RAGE ligands, longistatin specifically bound the RAGE V domain, and stimulated cultured HUVECs adhered to a longistatin-coated surface; this binding was dramatically inhibited by soluble RAGE or RAGE siRNA. Treatment of HUVECs with longistatin prior to stimulation substantially attenuated cellular oxidative stress and prevented NF-κB translocation, thereby reducing adhesion molecule and cytokine production. Recombinant longistatin inhibited RAGE-mediated migration of mouse peritoneal resident cells (mPRCs) and ameliorated inflammation in mouse footpad edema and pneumonia models. Importantly, tick bite upregulated RAGE ligands in skin, and endogenous longistatin attenuated RAGE-mediated inflammation during tick feeding. Our results suggest that longistatin is a RAGE antagonist that suppresses tick bite–associated inflammation, allowing successful blood-meal acquisition from hosts. PMID:25401185

  9. Receptor for advanced glycation end products is detrimental during influenza A virus pneumonia☆

    PubMed Central

    van Zoelen, Marieke A.D; van der Sluijs, Koenraad F.; Achouiti, Ahmed; Florquin, Sandrine; Braun-Pater, Jennie M.; Yang, Huan; Nawroth, Peter P.; Tracey, Kevin J.; Bierhaus, Angelika; van der Poll, Tom

    2015-01-01

    Pneumonia caused by influenza A virus (IAV) can have devastating effects, resulting in respiratory failure and death. The idea that a new influenza pandemic might occur in the near future has triggered renewed interests in IAV infection. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory processes. We here investigated the role of RAGE in the host response to IAV pneumonia using wild-type (wt) and RAGE deficient (−/−) mice. Whereas strong RAGE was constitutively expressed in the lungs of uninfected wt mice, in particular on endothelium, IAV pneumonia was associated with enhanced expression on endothelium and de novo expression on bronchial epithelium. Additionally, the high-affinity RAGE ligand high mobility group box 1 was upregulated during IAV pneumonia. RAGE−/− mice were relatively protected from IAV induced mortality and showed an improved viral clearance and enhanced cellular T cell response and activation of neutrophils. These data suggest that RAGE is detrimental during IAV pneumonia. PMID:19592063

  10. Advanced glycation end-products and insulin signaling in granulosa cells.

    PubMed

    Diamanti-Kandarakis, Evanthia; Chatzigeorgiou, Antonios; Papageorgiou, Efstathia; Koundouras, Dimitrios; Koutsilieris, Michael

    2016-07-01

    Advanced glycation end-products (AGEs) may interfere with insulin intracellular signaling and glucose transport in human granulosa cells, potentially affecting ovarian function, follicular growth, linked with diminished fertility. The potential interaction of AGEs with insulin signaling pathways and glucose transport was investigated in human granulosa KGN cells. KGN cells were cultured with variable concentrations of human glycated albumin (HGA, 50-200 µg/mL) or insulin (100 ng/mL). Combined treatments of KGN cells with insulin (100 ng/mL) and HGA (200 µg/mL) were also performed. p-AKT levels and glucose transporter type 4 (Glut-4) translocation analysis were performed by Western blot. Phosphatidylinositol-3-kinase (PI3K)-specific signaling was checked by using the PI3K-inhibitor, LY294002. p-AKT levels were significantly increased following insulin treatment compared to basal levels or HGA exposure. This insulin-mediated AKT-phosphorylation was PI3K-specific and it was inhibited after combined treatment of insulin and HGA. Furthermore, Glut-4 translocation from the cytoplasm to the membrane compartments of KGN cells was remarkably reduced after the combined treatment of insulin and HGA. The present findings support that AGEs interfere with insulin signaling in granulosa cells and prevent Glut-4 membrane translocation suggesting that intra ovarian AGEs accumulation, from endogenous or exogenous sources, may contribute to the pathophysiology of states characterized with anovulation and insulin resistance such as polycystic ovary syndrome. PMID:25956684

  11. A role for the receptor for advanced glycation end products in idiopathic pulmonary fibrosis.

    PubMed

    Englert, Judson M; Hanford, Lana E; Kaminski, Naftali; Tobolewski, Jacob M; Tan, Roderick J; Fattman, Cheryl L; Ramsgaard, Lasse; Richards, Thomas J; Loutaev, Inna; Nawroth, Peter P; Kasper, Michael; Bierhaus, Angelika; Oury, Tim D

    2008-03-01

    Idiopathic pulmonary fibrosis (IPF) is a severely debilitating disease associated with a dismal prognosis. There are currently no effective therapies for IPF, thus the identification of novel therapeutic targets is greatly needed. The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface receptors whose activation has been linked to various pathologies. In healthy adult animals, RAGE is expressed at the highest levels in the lung compared to other tissues. To investigate the hypothesis that RAGE is involved in IPF pathogenesis, we have examined its expression in two mouse models of pulmonary fibrosis and in human tissue from IPF patients. In each instance we observed a depletion of membrane RAGE and its soluble (decoy) isoform, sRAGE, in fibrotic lungs. In contrast to other diseases in which RAGE signaling promotes pathology, immunohistochemical and hydroxyproline quantification studies on aged RAGE-null mice indicate that these mice spontaneously develop pulmonary fibrosis-like alterations. Furthermore, when subjected to a model of pulmonary fibrosis, RAGE-null mice developed more severe fibrosis, as measured by hydroxyproline assay and histological scoring, than wild-type controls. Combined with data from other studies on mouse models of pulmonary fibrosis and human IPF tissues indicate that loss of RAGE contributes to IPF pathogenesis. PMID:18245812

  12. Advanced glycation end products delay corneal epithelial wound healing through reactive oxygen species generation.

    PubMed

    Shi, Long; Chen, Hongmei; Yu, Xiaoming; Wu, Xinyi

    2013-11-01

    Delayed healing of corneal epithelial wounds is a serious complication in diabetes. Advanced glycation end products (AGEs) are intimately associated with the diabetic complications and are deleterious to the wound healing process. However, the effect of AGEs on corneal epithelial wound healing has not yet been evaluated. In the present study, we investigated the effect of AGE-modified bovine serum albumin (BSA) on corneal epithelial wound healing and its underlying mechanisms. Our data showed that AGE-BSA significantly increased the generation of intracellular ROS in telomerase-immortalized human corneal epithelial cells. However, the generation of intracellular ROS was completely inhibited by antioxidant N-acetylcysteine (NAC), anti-receptor of AGEs (RAGE) antibodies, or the inhibitor of NADPH oxidase. Moreover, AGE-BSA increased NADPH oxidase activity and protein expression of NADPH oxidase subunits, p22phox and Nox4, but anti-RAGE antibodies eliminated these effects. Furthermore, prevention of intracellular ROS generation using NAC or anti-RAGE antibodies rescued AGE-BSA-delayed epithelial wound healing in porcine corneal organ culture. In conclusion, our results demonstrated that AGE-BSA impaired corneal epithelial wound healing ex vivo. AGE-BSA increased intracellular ROS generation through NADPH oxidase activation, which accounted for the delayed corneal epithelial wound healing. These results may provide better insights for understanding the mechanism of delayed healing of corneal epithelial wounds in diabetes. PMID:23955437

  13. Inhibitory effect of GSPE on RAGE expression induced by advanced glycation end products in endothelial cells.

    PubMed

    Zhang, Feng-Lei; Gao, Hai-Qing; Shen, Lin

    2007-10-01

    Advanced glycation end products' (AGEs) engagement of a cell-surface receptor for AGEs (RAGE) has been causally implicated in the pathogenesis of diabetic vascular complications via induction of reactive oxygen species (ROS) and subsequent alteration of many gene expressions, including RAGE itself. Grapeseed proanthocyanidin extract (GSPE), which is a naturally occurring polyphenolic compound, has been reported to possess potent radical-scavenging and antioxidant properties and to display significant cardiovascular protective action. In this study, we investigated whether GSPE could inhibit AGE-induced RAGE expression through interference with ROS generation in human umbilical-vein endothelial cells (HUVECs). AGE-modified bovine serum albumin (AGE-BSA) was prepared by incubating BSA with high-concentration glucose. Stimulation of cultured HUVECs with 200 microg/mL of AGE-BSA significantly enhanced intracellular ROS formation and subsequently upregulated the protein and mRNA expression of RAGE; unmodified BSA and GSPE alone had no effect. However, GSPE preincubation markedly downregulated AGE-induced surface expression of RAGE in a time- and concentration-dependent manner. In AGE-stimulated HUVECs, GSPE also dose-dependently decreased RAGE mRNA levels and inhibited AGE-induced ROS generation at defined time periods. These results demonstrate that GSPE can inhibit enhanced RAGE expression in AGE-exposed endothelial cells by suppressing ROS generation, thereby limiting the AGE-RAGE interaction. Hence, GSPE may have therapeutic potential in the prevention and treatment of vascular complications in diabetic patients. PMID:18049312

  14. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts

    PubMed Central

    Li, D.X.; Deng, T.Z.; Lv, J.; Ke, J.

    2014-01-01

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA), bovine serum albumin (BSA) alone, or given no treatment (control). Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80±5.50%, P<0.01) and increased apoptosis (11.31±1.73%, P<0.05). Hoechst 33258 staining and terminal-deoxynucleotidyl transferase-mediated nick-end labeling revealed that AGE-BSA significantly increased apoptosis of PDL fibroblasts. The results showed that the changes in PDL fibroblasts induced by AGE-BSA may explain how AGE-RAGE participates in and exacerbates periodontium destruction. PMID:25387669

  15. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts.

    PubMed

    Li, D X; Deng, T Z; Lv, J; Ke, J

    2014-12-01

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA), bovine serum albumin (BSA) alone, or given no treatment (control). Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80 ± 5.50%, P<0.01) and increased apoptosis (11.31 ± 1.73%, P<0.05). Hoechst 33258 staining and terminal-deoxynucleotidyl transferase-mediated nick-end labeling revealed that AGE-BSA significantly increased apoptosis of PDL fibroblasts. The results showed that the changes in PDL fibroblasts induced by AGE-BSA may explain how AGE-RAGE participates in and exacerbates periodontium destruction. PMID:25387669

  16. Survey of the distribution of a newly characterized receptor for advanced glycation end products in tissues.

    PubMed

    Brett, J; Schmidt, A M; Yan, S D; Zou, Y S; Weidman, E; Pinsky, D; Nowygrod, R; Neeper, M; Przysiecki, C; Shaw, A

    1993-12-01

    Advanced glycation end products (AGEs), the final products of nonenzymatic glycation and oxidation of proteins, are found in the plasma and accumulate in the tissues during aging and at an accelerated rate in diabetes. A novel integral membrane protein, termed receptor for AGE (RAGE), forms a central part of the cell surface binding site for AGEs. Using monospecific, polyclonal antibody raised to human recombinant and bovine RAGE, immunostaining of bovine tissues showed RAGE in the vasculature, endothelium, and smooth muscle cells and in mononuclear cells in the tissues. Consistent with these data, RAGE antigen and mRNA were identified in cultured bovine endothelium, vascular smooth muscle, and monocyte-derived macrophages. RAGE antigen was also visualized in bovine cardiac myocytes as well as in cultures of neonatal rat cardiac myocytes and in neural tissue where motor neurons, peripheral nerves, and a population of cortical neurons were positive. In situ hybridization confirmed the presence of RAGE mRNA in the tissues, and studies with rat PC12 pheochromocytes indicated that they provide a neuronal-related cell culture model for examining RAGE expression. Pathological studies of human atherosclerotic plaques showed infiltration of RAGE-expressing cells in the expanded intima. These results indicate that RAGE is present in multiple tissues and suggest the potential relevance of AGE-RAGE interactions for modulating properties of the vasculature as well as neural and cardiac function, prominent areas of involvement in diabetes and in the normal aging process. PMID:8256857

  17. Effect of advanced glycation end products on lens epithelial cells in vitro.

    PubMed

    Hong, S B; Lee, K W; Handa, J T; Joo, C K

    2000-08-18

    The extended exposure of proteins to reducing sugars leads to nonenzymatic glycation with the accumulation of advanced glycation end products (AGEs). Long-lived proteins, such as collagen and crystallins, are subjected to this modification, and are implicated as causal factors in several diseases including diabetic complications, cataracts, and arteriosclerosis. One means through which AGEs modulate cellular interactions is via binding to specific receptors. In the current study, the existence of AGEs in human anterior polar lens capsules of cataracts was confirmed using a combination of dot-immunoblot and fluorescent detection. Human lens epithelial cells (LECs) attached to anterior lens capsules expressed mRNA for the receptor for AGEs (RAGE). The interaction of LECs with AGEs using bovine lens epithelial explants demonstrated that AGEs induced mRNAs and proteins of fibronectin, collagen type I, aberrant extracellular matrix proteins, and alpha-SMA, a specific marker for myofibroblastic cells. These findings suggest that AGEs may alter cellular functions which induce mRNAs and proteins associated with fibrosis in LECs. PMID:10944440

  18. Ameliorating Effect of Akebia quinata Fruit Extracts on Skin Aging Induced by Advanced Glycation End Products.

    PubMed

    Shin, Seoungwoo; Son, Dahee; Kim, Minkyung; Lee, Seungjun; Roh, Kyung-Baeg; Ryu, Dehun; Lee, Jongsung; Jung, Eunsun; Park, Deokhoon

    2015-11-01

    The accumulation of free radicals and advanced glycation end products (AGEs) in the skin plays a very important role in skin aging. Both are known to interact with each other. Therefore, natural compounds or extracts that possess both antioxidant and antiglycation activities might have great antiageing potential. Akebia quinata fruit extract (AQFE) has been used to treat urinary tract inflammatory disease in traditional Korean and Chinese medicines. In the present study, AQFE was demonstrated to possess antioxidant and antiglycation activity. AQFE protects human dermal fibroblasts (HDFs) from oxidative stress and inhibits cellular senescence induced by oxidative stress. We also found that AQFE inhibits glycation reaction between BSA and glucose. The antiglycation activity of AQFE was dose-dependent. In addition, the antiglycation activity of AQFE was confirmed in a human skin explant model. AQFE reduced CML expression and stimulated fibrillin-1 expression in comparison to the methyglyoxal treatment. In addition, the possibility of the extract as an anti-skin aging agent has also been clinically validated. Our analysis of the crow's feet wrinkle showed that there was a decrease in the depth of deep furrows in RI treated with AQFE cream over an eight-week period. The overall results suggest that AQFE may work as an anti-skin aging agent by preventing oxidative stress and other complications associated with AGEs formation. PMID:26569300

  19. Quercetin inhibits advanced glycation end product formation by trapping methylglyoxal and glyoxal.

    PubMed

    Li, Xiaoming; Zheng, Tiesong; Sang, Shengmin; Lv, Lishuang

    2014-12-17

    Methylglyoxal (MGO) and glyoxal (GO) not only are endogenous metabolites but also exist in exogenous resources, such as foods, beverages, urban atmosphere, and cigarette smoke. They have been identified as reactive dicarbonyl precursors of advanced glycation end products (AGEs), which have been associated with diabetes-related long-term complications. In this study, quercetin, a natural flavonol found in fruits, vegetables, leaves, and grains, could effectively inhibit the formation of AGEs in a dose-dependent manner via trapping reactive dicarbonyl compounds. More than 50.5% of GO and 80.1% of MGO were trapped at the same time by quercetin within 1 h under physiological conditions. Quercetin and MGO (or GO) were combined at different ratios, and the products generated from this reaction were analyzed with LC-MS. Both mono-MGO and di-MGO adducts of quercetin were detected in this assay using LC-MS, but only tiny amounts of mono-GO adducts of quercetin were found. Additionally, di-MGO adducts were observed as the dominant product with prolonged incubation time. In the bovine serum albumin (BSA)-MGO/GO system, quercetin traps MGO and GO directly and then significantly inhibits the formation of AGEs. PMID:25412188

  20. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts.

    PubMed

    Li, D X; Deng, T Z; Lv, J; Ke, J

    2014-09-19

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA), bovine serum albumin (BSA) alone, or given no treatment (control). Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80±5.50%, P<0.01) and increased apoptosis (11.31±1.73%, P<0.05). Hoechst 33258 staining and terminal-deoxynucleotidyl transferase-mediated nick-end labeling revealed that AGE-BSA significantly increased apoptosis of PDL fibroblasts. The results showed that the changes in PDL fibroblasts induced by AGE-BSA may explain how AGE-RAGE participates in and exacerbates periodontium destruction. PMID:25250588

  1. Update on Mechanisms of Renal Tubule Injury Caused by Advanced Glycation End Products

    PubMed Central

    Sun, Hong; Yuan, Yang; Sun, Zilin

    2016-01-01

    Diabetic nephropathy (DN) caused by advanced glycation end products (AGEs) may be associated with lipid accumulation in the kidneys. This study was designed to investigate whether Nε-(carboxymethyl) lysine (CML, a member of the AGEs family) increases lipid accumulation in a human renal tubular epithelial cell line (HK-2) via increasing cholesterol synthesis and uptake and reducing cholesterol efflux through endoplasmic reticulum stress (ERS). Our results showed that CML disrupts cholesterol metabolism in HK-2 cells by activating sterol regulatory element-binding protein 2 (SREBP-2) and liver X receptor (LXR), followed by an increase in 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR) mediated cholesterol synthesis and low density lipoprotein receptor (LDLr) mediated cholesterol uptake and a reduction in ATP-binding cassette transporter A1 (ABCA1) mediated cholesterol efflux, ultimately causing lipid accumulation in HK-2 cells. All of these responses could be suppressed by an ERS inhibitor, which suggests that CML causes lipid accumulation in renal tubule cells through ERS and that the inhibition of ERS is a potential novel approach to treating CML-induced renal tubular foam cell formation. PMID:27034941

  2. Advanced glycation end-products: a biological consequence of lifestyle contributing to cancer disparity.

    PubMed

    Turner, David P

    2015-05-15

    Low income, poor diet, obesity, and a lack of exercise are interrelated lifestyle factors that can profoundly alter our biologic make up to increase cancer risk, growth, and development. We recently reported a potential mechanistic link between carbohydrate-derived metabolites and cancer, which may provide a biologic consequence of lifestyle that can directly affect tumor biology. Advanced glycation end-products (AGE) are reactive metabolites produced as a by-product of sugar metabolism. Failure to remove these highly reactive metabolites can lead to protein damage, aberrant cell signaling, increased stress responses, and decreased genetic fidelity. Critically, AGE accumulation is also directly affected by our lifestyle choices and shows a race-specific, tumor-dependent pattern of accumulation in cancer patients. This review will discuss the contribution of AGEs to the cancer phenotype, with a particular emphasis on their biologic links with the socioeconomic and environmental risk factors that drive cancer disparity. Given the potential benefits of lifestyle changes and the potential biologic role of AGEs in promoting cancer, opportunities exist for collaborations affecting basic, translational, epidemiologic, and cancer prevention initiatives. PMID:25920350

  3. Eucommia ulmoides extracts prevent the formation of advanced glycation end products.

    PubMed

    Sugawa, Hikari; Ohno, Rei-Ichi; Shirakawa, Jun-Ichi; Nakajima, Akari; Kanagawa, Amane; Hirata, Tetsuya; Ikeda, Tsuyoshi; Moroishi, Narumi; Nagai, Mime; Nagai, Ryoji

    2016-06-15

    Proteins non-enzymatically react with reducing sugars to form advanced glycation end-products (AGEs), resulting in the induction of protein denaturation. Because the levels of AGE increase with age and are elevated in age-related diseases, such as diabetes and atherosclerosis, the intake of compound(s) that inhibit the formation of AGEs by daily meal may represent a potential strategy for preventing age-related diseases. In this study, we measured the inhibitory effects of several Eucommia ulmoides extracts on the formation of AGEs, N(ε)-(carboxymethyl)lysine (CML) and N(ω)-(carboxymethyl)arginine (CMA). Although a crude extract obtained from E. ulmoides bark is widely used as herbal medicine, E. ulmoides leaf extract (ELE) inhibited CML and CMA formation more effectively during the incubation of gelatin with ribose. Therefore, the inhibitory effects of compounds present in ELE on CML and CMA formation were studied. As a result, isoquercetin showed the strongest inhibitory effect of all the tested ELE components. These results indicate that the oral intake of ELE may inhibit the formation of AGEs, thereby ameliorating age-related diseases. PMID:27080730

  4. Advanced glycation end products induce differential structural modifications and fibrillation of albumin

    NASA Astrophysics Data System (ADS)

    Awasthi, Saurabh; Sankaranarayanan, Kamatchi; Saraswathi, N. T.

    2016-06-01

    Glycation induced amyloid fibrillation is fundamental to the development of many neurodegenerative and cardiovascular complications. Excessive non-enzymatic glycation in conditions such as hyperglycaemia results in the increased accumulation of advanced glycation end products (AGEs). AGEs are highly reactive pro-oxidants, which can lead to the activation of inflammatory pathways and development of oxidative stress. Recently, the effect of non-enzymatic glycation on protein structure has been the major research area, but the role of specific AGEs in such structural alteration and induction of fibrillation remains undefined. In this study, we determined the specific AGEs mediated structural modifications in albumin mainly considering carboxymethyllysine (CML), carboxyethyllysine (CEL), and argpyrimidine (Arg-P) which are the major AGEs formed in the body. We studied the secondary structural changes based on circular dichroism (CD) and spectroscopic analysis. The AGEs induced fibrillation was determined by Congo red binding and examination of scanning and transmission electron micrographs. The amyloidogenic regions in the sequence of BSA were determined using FoldAmyloid. It was observed that CEL modification of BSA leads to the development of fibrillar structures, which was evident from both secondary structure changes and TEM analysis.

  5. Hepatocyte growth factor protects human endothelial cells against advanced glycation end products-induced apoposis

    SciTech Connect

    Zhou Yijun . E-mail: zhou-yijun@hotmail.com; Wang Jiahe; Zhang Jin

    2006-06-02

    Advanced glycation end products (AGEs) form by a non-enzymatic reaction between reducing sugars and biological proteins, which play an important role in the pathogenesis of atherosclerosis. In this study, we assessed AGEs effects on human umbilical vein endothelial cells (HUVECs) growth, proliferation and apoptosis. Additionally, we investigated whether hepatocyte growth factor (HGF), an anti-apoptotic factor for endothelial cells, prevents AGEs-induced apoptosis of HUVECs. HUVECs were treated with AGEs in the presence or absence of HGF. Treatment of HUVECs with AGEs changed cell morphology, decreased cell viability, and induced DNA fragmentation, leading to apoptosis. Apoptosis was induced by AGEs in a dose- and time-dependent fashion. AGEs markedly elevated Bax and decreased NF-{kappa}B, but not Bcl-2 expression. Additionally, AGEs significantly inhibited cell growth through a pro-apoptotic action involving caspase-3 and -9 activations in HUVECs. Most importantly, pretreatment with HGF protected against AGEs-induced cytotoxicity in the endothelial cells. HGF significantly promoted the expression of Bcl-2 and NF-{kappa}B, while decreasing the activities of caspase-3 and -9 without affecting Bax level. Our data suggest that AGEs induce apoptosis in endothelial cells. HGF effectively attenuate AGEs-induced endothelial cell apoptosis. These findings provide new perspectives in the role of HGF in cardiovascular disease.

  6. Ameliorating Effect of Akebia quinata Fruit Extracts on Skin Aging Induced by Advanced Glycation End Products

    PubMed Central

    Shin, Seoungwoo; Son, Dahee; Kim, Minkyung; Lee, Seungjun; Roh, Kyung-Baeg; Ryu, Dehun; Lee, Jongsung; Jung, Eunsun; Park, Deokhoon

    2015-01-01

    The accumulation of free radicals and advanced glycation end products (AGEs) in the skin plays a very important role in skin aging. Both are known to interact with each other. Therefore, natural compounds or extracts that possess both antioxidant and antiglycation activities might have great antiageing potential. Akebia quinata fruit extract (AQFE) has been used to treat urinary tract inflammatory disease in traditional Korean and Chinese medicines. In the present study, AQFE was demonstrated to possess antioxidant and antiglycation activity. AQFE protects human dermal fibroblasts (HDFs) from oxidative stress and inhibits cellular senescence induced by oxidative stress. We also found that AQFE inhibits glycation reaction between BSA and glucose. The antiglycation activity of AQFE was dose-dependent. In addition, the antiglycation activity of AQFE was confirmed in a human skin explant model. AQFE reduced CML expression and stimulated fibrillin-1 expression in comparison to the methyglyoxal treatment. In addition, the possibility of the extract as an anti-skin aging agent has also been clinically validated. Our analysis of the crow’s feet wrinkle showed that there was a decrease in the depth of deep furrows in RI treated with AQFE cream over an eight-week period. The overall results suggest that AQFE may work as an anti-skin aging agent by preventing oxidative stress and other complications associated with AGEs formation. PMID:26569300

  7. Singlet oxygen induced advanced glycation end-product photobleaching of in vivo human fingertip autofluorescence

    NASA Astrophysics Data System (ADS)

    Deng, Bin; Simental, Anabel; Lutz, Patrick; Shaheen, George; Chaiken, Joseph

    2012-01-01

    Nonenzymatic glycation and oxidation of ubiquitous proteins in vivo leads to irreversible formation of advanced glycation end products (AGEs). Due to their relatively long half life and low clearance rate AGEs tend to accumulate within static tissues and the circulatory system. Spectra obtained using 830 nm near-infrared (NIR) excitation suggest that the so-called "autofluorescence" from all tissues has a finite number of sources but the fact that senior and diabetic subjects produce more than other members of the general population suggests that a significant portion of the total autofluorescence from all sources originates from AGEs. Using pentosidine generated in a reaction mixture as described by Monnier as representative, an in vitro study unveiled very similar fluorescence and photobleaching pattern as observed for autofluorescence in vivo. A series of oxygen, air and argon purging experiments on the pentosidine-generating reaction mixture suggests that pentosidine is a singlet oxygen sensitizer and secondary reactions between the pentosidine itself and/or other fluorophores and the photosensitized singlet oxygen explain the observed photobleaching. Ab initio Gaussian calculations on pentosidine reveal the existence of low-lying triplet excited states required for the sensitization of ground state oxygen. A commercially available product known as singlet oxygen sensor green (SOSG) that specifically serves as a singlet oxygen detection reagent confirms the generation of singlet oxygen from NIR irradiated pentosidine trimixture. This study provides one definite chemical mechanism for understanding in vivo human skin autofluorescence and photobleaching.

  8. Short-term effects of dietary advanced glycation end products in rats.

    PubMed

    Poulsen, Malene W; Andersen, Jeanette M; Hedegaard, Rikke V; Madsen, Andreas N; Krath, Britta N; Monošík, Rastislav; Bak, Monika J; Nielsen, John; Holst, Birgitte; Skibsted, Leif H; Larsen, Lesli H; Dragsted, Lars O

    2016-02-28

    Dietary advanced glycation end products (AGE) formed during heating of food have gained interest as potential nutritional toxins with adverse effects on inflammation and glucose metabolism. In the present study, we investigated the short-term effects of high and low molecular weight (HMW and LMW) dietary AGE on insulin sensitivity, expression of the receptor for AGE (RAGE), the AGE receptor 1 (AGER1) and TNF-α, F2-isoprostaglandins, body composition and food intake. For 2 weeks, thirty-six Sprague-Dawley rats were fed a diet containing 20% milk powder with different proportions of this being given as heated milk powder (0, 40 or 100%), either native (HMW) or hydrolysed (LMW). Gene expression of RAGE and AGER1 in whole blood increased in the group receiving a high AGE LMW diet, which also had the highest urinary excretion of the AGE, methylglyoxal-derived hydroimidazolone 1 (MG-H1). Urinary excretion of N ε-carboxymethyl-lysine increased with increasing proportion of heat-treated milk powder in the HMW and LMW diets but was unrelated to gene expression. There was no difference in insulin sensitivity, F2-isoprostaglandins, food intake, water intake, body weight or body composition between the groups. In conclusion, RAGE and AGER1 expression can be influenced by a high AGE diet after only 2 weeks in proportion to MG-H1 excretion. No other short-term effects were observed. PMID:26824730

  9. Unexpected Crosslinking and Diglycation as Advanced Glycation End-Products from Glyoxal

    NASA Astrophysics Data System (ADS)

    Lopez-Clavijo, Andrea F.; Duque-Daza, Carlos A.; Soulby, Andrew; Canelon, Isolda Romero; Barrow, Mark; O'Connor, Peter B.

    2014-12-01

    Glyoxal-derived advanced glycation end-products (AGEs) are formed in physiological systems affecting protein/peptide function and structure. These AGEs are generated during aging and chronic diseases such as diabetes and are considered arginine glycating agents. Thus, the study of glyoxal-derived AGEs in lysine residues and amino acid competition is addressed here using acetylated and non-acetylated undecapeptides, with one arginine and one lysine residue available for glycation. Tandem mass spectrometry results from a Fourier transform ion cyclotron resonance mass spectrometer showed glycated species at both the arginine and lysine residues. One species with the mass addition of 116.01096 Da is formed at the arginine residue. A possible structure is proposed to explain this finding (Nδ-[2-(dihydroxymethyl)-2H,3aH,4H,6aH-[1, 3]dioxolo[5,6-d]imidazolin-5-yl]-L-ornithine-derived AGE). The second species corresponded to intramolecular crosslink involving the lysine residue and its presence is checked with ion-mobility mass spectrometry.

  10. Antibody-based detection of advanced glycation end-products: promises vs. limitations.

    PubMed

    Nagai, Ryoji; Shirakawa, Jun-Ichi; Ohno, Rei-Ichi; Hatano, Kota; Sugawa, Hikari; Arakawa, Shoutaro; Ichimaru, Kenta; Kinoshita, Shoh; Sakata, Noriyuki; Nagai, Mime

    2016-08-01

    Advanced glycation end-products (AGEs) of the Maillard reaction were originally measured according to their fluorescent and browning properties. A subsequent study with instrumental analyses such as high-performance liquid chromatography and gas chromatography mass spectrometry more clearly demonstrated the involvement of each AGE structure in pathological conditions. Furthermore, immunochemical methods have also been developed to clarify the localization of AGEs in tissues and measurement of AGEs in multiple clinical samples. Although the involvement of AGEs in age-related diseases has progressed due to immunochemical techniques, the relationship between AGE structure and diseases has not been clear because little was known about the epitope structure of each anti-AGE antibody. However, the development of epitope-identified antibodies against AGEs has made it possible to clarify AGE structures involved in diseases. This review discusses not only the usability of anti-AGE antibodies to evaluate AGEs and disease pathology and screen AGE inhibitors, but also describes their usage. PMID:27421861

  11. Increased Levels of Circulating Advanced Glycation End-Products in Menopausal Women with Osteoporosis

    PubMed Central

    Yang, Deng-Ho; Chiang, Tsay-I; Chang, I-Chang; Lin, Fu-Huang; Wei, Cheng-Chung; Cheng, Ya-Wen

    2014-01-01

    Background: Advanced glycation end-products (AGEs) can accumulate in organs and tissues during ageing and diabetes. Increased levels of AGEs are found in the bone tissue of patients with osteoporosis. The purpose of this study was to evaluate circulating AGEs in patients with osteoporosis. Methods: We evaluated plasma AGEs, osteoporosis-related biomarkers, and bone mass in 82 menopausal women with osteoporosis or osteopenia, 16 young women with osteopenia, and 43 healthy women without osteoporosis or osteopenia. Results: Higher levels of serum AGEs were found in the osteoporosis or osteopenia group compared to healthy women (P < 0.0001). A negative correlation was observed between serum AGEs and lumbar spine bone density (BMD of lumbar spine, r = -0.249, P = 0.028; T-score of lumbar spine, r = -0.261, P = 0.021). Women with a increased level of serum AGEs (> 8.12 U/mL) had a 5.34-fold risk of osteopenia regarding lumbar spine T-score and a 3.31-fold risk of osteopenia regarding the hip T-score. Conclusion: Serum AGEs could be used to monitor the severity and progression of osteoporosis. An increased serum level of AGEs was associated with impaired bone formation and was a risk factor for the development of osteoporosis. Targeting AGEs may represent a novel therapeutic approach for primary or secondary osteoporosis. PMID:24688308

  12. Protection Effect of Endomorphins on Advanced Glycation End Products Induced Injury in Endothelial Cells

    PubMed Central

    Liu, Jing; Yan, Liping; Niu, Ruilan; Tian, Limin; Zhang, Qi; Quan, Jinxing; Liu, Hua; Wei, Suhong; Guo, Qian

    2013-01-01

    Endomorphins (EMs) have a very important bridge-function in cardiovascular, endocrinological, and neurological systems. This study is to investigate the effects of EMs on the synthesis and secretion of vasoactive substances induced by advanced glycation end products in primary cultured human umbilical vein endothelial cells (HUVECs). Firstly, HUVECs were stimulated with AGEs-bovine serum albumin (AGEs-BSA), bovine serum albumin (BSA), or both AGEs-BSA and EMs together, respectively. Then, HUVEC survival rate was calculated by MTT assay, the levels of NO, endothelial nitric oxide synthase (eNOS), and inducible nitric oxide synthase (iNOS) were detected by colorimetric analysis, and the contents of endothelin-1 (ET-1) were detected by ELISA. The mRNA levels of eNOS and ET-1 were measured by RT-PCR. The expression of p38 mitogen-activated protein kinase (p38 MAPK) was detected by immunofluorescence assay. The results showed that the mRNA expression and secretion of eNOS were significantly enhanced after incubation with EMs compared to those with AGEs-BSA, while the secretion of NO and iNOS, mRNA expression, and secretion of ET-1 had opposite changes. The fluorescence intensity of p38MAPK in nuclear was decreased after pretreatment with EMs compared to incubation with AGEs-BSA. Conclusion. The present study suggests that EMs have certain protection effect on AGEs-BSA-induced injury in HUVEC. PMID:23671848

  13. Chronic Spontaneous Urticaria Is Characterized by Lower Serum Advanced Glycation End-Products

    PubMed Central

    Grzanka, Alicja; Damasiewicz-Bodzek, Aleksandra; Machura, Edyta; Szumska, Magdalena; Tyrpień-Golder, Krystyna; Mazur, Bogdan; Kasperska-Zajac, Alicja

    2014-01-01

    Background. Chronic spontaneous urticaria (CSU) is associated with activation of acute phase response. On the other hand, it is known that systemic inflammation may lead to increased formation of advanced glycation end-products (AGEs), associated with pathogenesis of various diseases. Aim. We aim to test whether chronic inflammation manifested by activated acute phase response may provide a mechanism for increased serum AGEs concentration in CSU. Methods. Concentrations of AGEs were measured spectrofluorimetrically in serum of CSU patients and the healthy subjects. Results. Serum AGEs and albumin concentrations in CSU patients were significantly lower as compared with the healthy subjects. Serum CRP concentration was significantly higher in patients with CSU than in the controls. Significant positive correlation was observed between AGEs and albumin concentrations in the subjects. Conclusions. CSU is not associated with increased circulating AGEs concentrations, despite the enhanced systemic inflammatory response. Paradoxical decrease of serum AGEs concentrations is probably a reflection of lower concentration of “negative acute phase proteins” such as albumin. PMID:25180195

  14. Importance of advanced glycation end products in diabetes-associated cardiovascular and renal disease.

    PubMed

    Cooper, Mark E

    2004-12-01

    Although the features of diabetic cardiomyopathy, atherosclerosis, and nephropathy have been clinically characterized, the pathogenesis and the mechanisms underlying the abnormalities in the diabetic heart and kidney are not fully understood. During the past several years, in an attempt to discover interventions for diabetes-related complications, researchers have refocused their attention from the hemodynamic aspects of the disease to the biochemical interactions of glucose and proteins. Diabetes is a disorder of chronic hyperglycemia, and glucose participates in diabetic complications such as atherosclerosis, cardiac dysfunction, and nephropathy. Chronic hyperglycemia accelerates the reaction between glucose and proteins and leads to the formation of advanced glycation end products (AGE), which form irreversible cross-links with many macromolecules such as collagen. In diabetes, these AGE accumulate in tissues at an accelerated rate. The development of the novel compound dimethyl-3-phenacylthiazolium chloride (alagebrium chloride), which chemically breaks AGE cross-links, led to several preclinical animal studies that showed an attenuation or reversal of disease processes of the heart and kidney. In diabetes, AGE not only structurally stiffen structural collagen backbones but also act as agonists to AGE receptors (RAGE) on various cell types, which stimulate the release of profibrotic growth factors, promote collagen deposition, increase inflammation, and ultimately lead to tissue fibrosis. In the heart, large vessels, and kidney, these reactions produce diastolic dysfunction, atherosclerosis, and renal fibrosis. Administration of the cross-link breaker alagebrium chloride in these diabetic animals attenuates these pathologic phenomena, restoring functionality to the heart, vasculature, and kidney. PMID:15607433

  15. Advanced glycation end products suppress osteoblastic differentiation of stromal cells by activating endoplasmic reticulum stress.

    PubMed

    Tanaka, Ken-ichiro; Yamaguchi, Toru; Kaji, Hiroshi; Kanazawa, Ippei; Sugimoto, Toshitsugu

    2013-08-30

    Advanced glycation end products (AGEs) are involved in bone quality deterioration in diabetes mellitus. We previously showed that AGE2 or AGE3 inhibited osteoblastic differentiation and mineralization of mouse stromal ST2 cells, and also induced apoptosis and decreased cell growth. Although quality management for synthesized proteins in endoplasmic reticulum (ER) is crucial for the maturation of osteoblasts, the effects of AGEs on ER stress in osteoblast lineage are unknown. We thus examined roles of ER stress in AGE2- or AGE3-induced suppression of osteoblastogenesis of ST2 cells. An ER stress inducer, thapsigargin (TG), induced osteoblastic differentiation of ST2 cells by increasing the levels of Osterix, type 1 collagen (Col1), alkaline phosphatase (ALP) and osteocalcin (OCN) mRNA. AGE2 or AGE3 suppressed the levels of ER stress sensors such as IRE1α, ATF6 and OASIS, while they increased the levels of PERK and its downstream molecules, ATF4. A reduction in PERK level by siRNA did not affect the AGEs-induced suppression of the levels of Osterix, Col1 and OCN mRNA. In conclusion, AGEs inhibited the osteoblastic differentiation of stromal cells by suppressing ER stress sensors and accumulating abnormal proteins in the cells. This process might accelerate AGEs-induced suppression of bone formation found in diabetes mellitus. PMID:23933252

  16. The inhibition of advanced glycation end-products-induced retinal vascular permeability by silver nanoparticles.

    PubMed

    Sheikpranbabu, Sardarpasha; Kalishwaralal, Kalimuthu; Lee, Kyung-Jin; Vaidyanathan, Ramanathan; Eom, Soo Hyun; Gurunathan, Sangiliyandi

    2010-03-01

    The increased permeability of the blood-retinal barrier is known to occur in patients with diabetes, and this defect contributes to retinal edema. This study aimed to determine the effects of silver nanoparticles (Ag-NPs) on advanced glycation end-products (AGEs)-induced endothelial cell permeability. Cultured porcine retinal endothelial cells (PRECs) were exposed to AGE-modified bovine serum albumin (AGE-BSA) and the endothelial cell permeability was detected by measuring the flux of RITC-dextran across the PREC monolayers. We found that AGE-BSA increased the dextran flux across a PREC monolayer and Ag-NPs blocked the solute flux induced by AGE-BSA. In order to understand the underlying signaling mechanism of Ag-NPs on the inhibitory effect of AGE-BSA-induced permeability, we demonstrated that Ag-NPs could inhibit the AGE-BSA-induced permeability via Src kinase pathway. AGE-BSA also increased the PREC permeability by stimulating the expression of intracellular adhesion molecule-1 (ICAM-1) and decreased the expression of occludin and ZO-1. Further, Ag-NPs inhibited the AGE-BSA-induced permeability by increased expression of tight junction proteins occludin and ZO-1, co-incident with an increase in barrier properties of endothelial monolayer. Together, our results indicate that Ag-NPs could possibly act as potent anti-permeability molecule by targeting the Src signaling pathway and tight junction proteins and it offers potential targets to inhibit the ocular related diseases. PMID:19963272

  17. Does Accumulation of Advanced Glycation End Products Contribute to the Aging Phenotype?

    PubMed Central

    Nicklett, Emily J.; Ferrucci, Luigi

    2010-01-01

    Background. Aging is a complex multifactorial process characterized by accumulation of deleterious changes in cells and tissues, progressive deterioration of structural integrity and physiological function across multiple organ systems, and increased risk of death. Methods. We conducted a review of the scientific literature on the relationship of advanced glycation end products (AGEs) with aging. AGEs are a heterogeneous group of bioactive molecules that are formed by the nonenzymatic glycation of proteins, lipids, and nucleic acids. Results. Humans are exposed to AGEs produced in the body, especially in individuals with abnormal glucose metabolism, and AGEs ingested in foods. AGEs cause widespread damage to tissues through upregulation of inflammation and cross-linking of collagen and other proteins. AGEs have been shown to adversely affect virtually all cells, tissues, and organ systems. Recent epidemiological studies demonstrate that elevated circulating AGEs are associated with increased risk of developing many chronic diseases that disproportionally affect older individuals. Conclusions. Based on these data, we propose that accumulation of AGEs accelerate the multisystem functional decline that occurs with aging, and therefore contribute to the aging phenotype. Exposure to AGEs can be reduced by restriction of dietary intake of AGEs and drug treatment with AGE inhibitors and AGE breakers. Modification of intake and circulating levels of AGEs may be a possible strategy to promote health in old age, especially because most Western foods are processed at high temperature and are rich in AGEs. PMID:20478906

  18. Glucosepane: a poorly understood advanced glycation end product of growing importance for diabetes and its complications.

    PubMed

    Monnier, Vincent M; Sun, Wanjie; Sell, David R; Fan, Xingjun; Nemet, Ina; Genuth, Saul

    2014-01-01

    Advanced glycation end products (AGEs) represent a family of protein, peptide, amino acid, nucleic acid and lipid adducts formed by the reaction of carbonyl compounds derived directly or indirectly from glucose, ascorbic acid and other metabolites such as methylglyoxal. AGE formation in diabetes is of growing importance for their role as markers and potential culprits of diabetic complications, in particular retinopathy, nephropathy and neuropathy. Development of sensitive and specific assays utilizing liquid chromatography mass spectrometry with isotope dilution method has made it possible to detect and quantitate non-UV active AGEs such as carboxymethyl-lysine and glucosepane, the most prevalent AGE and protein crosslink of the extracellular matrix. Below we review studies on AGE formation in two skin biopsies obtained near the closeout of the Diabetes Control and Complications Trial (DCCT), one of which was processed in 2011 for assay of novel AGEs. The results of these analyses show that while several AGEs are associated and predict complication progression, the glucose/fructose-lysine/glucosepane AGE axis is one of the most robust markers for microvascular disease, especially retinopathy, in spite of adjustment for past or future average glycemia. Yet overall little biological and clinical information is available on glucosepane, making this review a call for data in a field of growing importance for diabetes and chronic metabolic diseases of aging. PMID:23787467

  19. Clearance kinetics and matrix binding partners of the receptor for advanced glycation end products.

    PubMed

    Milutinovic, Pavle S; Englert, Judson M; Crum, Lauren T; Mason, Neale S; Ramsgaard, Lasse; Enghild, Jan J; Sparvero, Louis J; Lotze, Michael T; Oury, Tim D

    2014-01-01

    Elucidating the sites and mechanisms of sRAGE action in the healthy state is vital to better understand the biological importance of the receptor for advanced glycation end products (RAGE). Previous studies in animal models of disease have demonstrated that exogenous sRAGE has an anti-inflammatory effect, which has been reasoned to arise from sequestration of pro-inflammatory ligands away from membrane-bound RAGE isoforms. We show here that sRAGE exhibits in vitro binding with high affinity and reversibly to extracellular matrix components collagen I, collagen IV, and laminin. Soluble RAGE administered intratracheally, intravenously, or intraperitoneally, does not distribute in a specific fashion to any healthy mouse tissue, suggesting against the existence of accessible sRAGE sinks and receptors in the healthy mouse. Intratracheal administration is the only effective means of delivering exogenous sRAGE to the lung, the organ in which RAGE is most highly expressed; clearance of sRAGE from lung does not differ appreciably from that of albumin. PMID:24642901

  20. Receptor for Advanced Glycation End Products and Its Involvement in Inflammatory Diseases

    PubMed Central

    Talib, Herni; Tie, Tung Hing; Nordin, Norshariza

    2013-01-01

    The receptor for advanced glycation end products (RAGE) is a transmembrane receptor of the immunoglobulin superfamily, capable of binding a broad repertoire of ligands. RAGE-ligands interaction induces a series of signal transduction cascades and lead to the activation of transcription factor NF-κB as well as increased expression of cytokines, chemokines, and adhesion molecules. These effects endow RAGE with the role in the signal transduction from pathogen substrates to cell activation during the onset and perpetuation of inflammation. RAGE signaling and downstream pathways have been implicated in a wide spectrum of inflammatory-related pathologic conditions such as arteriosclerosis, Alzheimer's disease, arthritis, acute respiratory failure, and sepsis. Despite the significant progress in other RAGE studies, the functional importance of the receptor in clinical situations and inflammatory diseases still remains to be fully realized. In this review, we will summarize current understandings and lines of evidence on the molecular mechanisms through which RAGE signaling contributes to the pathogenesis of the aforementioned inflammation-associated conditions. PMID:24102034

  1. Advanced glycation end products (AGEs) promote melanogenesis through receptor for AGEs.

    PubMed

    Lee, Eun Jung; Kim, Ji Young; Oh, Sang Ho

    2016-01-01

    Accumulation of advanced glycation end products (AGEs) is linked with development or aggravation of many degenerative processes or disorders, including aging and atherosclerosis. AGEs production in skin cells is known to promote stiffness and loss of elasticity through their buildup in connective tissue. However, the impact of AGEs has yet to be fully explored in melanocytes. In this study, we confirmed the existence of receptor for AGE (RAGE) in melanocytes in western blot and immunofluorescence along with increased melanin production in ex vivo skin organ culture and in vitro melanocyte culture following AGEs treatment. Cyclic AMP response element-binding protein (CREB) and extracellular signal-regulated kinases (ERK) 1/2 are considered as key regulatory proteins in AGEs-induced melanogenesis. In addition, blockage experiment using anti-RAGE blocking antibody has indicated that RAGE plays a pivotal role in AGE-mediated melanogenesis. Therefore, it is apparent that AGEs, known markers of aging, promote melanogenesis via RAGE. In addition, AGEs could be implicated in pigmentation associated with photoaging according to the results of increased secretion of AGEs from keratinocytes following UV irradiation. AGE-mediated melanogenesis may thus hold promise as a novel mean of altering skin pigmentation. PMID:27293210

  2. Advanced Glycation End-Products Enhance Lung Cancer Cell Invasion and Migration

    PubMed Central

    Hsia, Te-Chun; Yin, Mei-Chin; Mong, Mei-Chin

    2016-01-01

    Effects of carboxymethyllysine (CML) and pentosidine, two advanced glycation end-products (AGEs), upon invasion and migration in A549 and Calu-6 cells, two non-small cell lung cancer (NSCLC) cell lines were examined. CML or pentosidine at 1, 2, 4, 8 or 16 μmol/L were added into cells. Proliferation, invasion and migration were measured. CML or pentosidine at 4–16 μmol/L promoted invasion and migration in both cell lines, and increased the production of reactive oxygen species, tumor necrosis factor-α, interleukin-6 and transforming growth factor-β1. CML or pentosidine at 2–16 μmol/L up-regulated the protein expression of AGE receptor, p47phox, intercellular adhesion molecule-1 and fibronectin in test NSCLC cells. Matrix metalloproteinase-2 protein expression in A549 and Calu-6 cells was increased by CML or pentosidine at 4–16 μmol/L. These two AGEs at 2–16 μmol/L enhanced nuclear factor κ-B (NF-κ B) p65 protein expression and p38 phosphorylation in A549 cells. However, CML or pentosidine at 4–16 μmol/L up-regulated NF-κB p65 and p-p38 protein expression in Calu-6 cells. These findings suggest that CML and pentosidine, by promoting the invasion, migration and production of associated factors, benefit NSCLC metastasis. PMID:27517907

  3. Advanced glycation end products induce differential structural modifications and fibrillation of albumin.

    PubMed

    Awasthi, Saurabh; Sankaranarayanan, Kamatchi; Saraswathi, N T

    2016-06-15

    Glycation induced amyloid fibrillation is fundamental to the development of many neurodegenerative and cardiovascular complications. Excessive non-enzymatic glycation in conditions such as hyperglycaemia results in the increased accumulation of advanced glycation end products (AGEs). AGEs are highly reactive pro-oxidants, which can lead to the activation of inflammatory pathways and development of oxidative stress. Recently, the effect of non-enzymatic glycation on protein structure has been the major research area, but the role of specific AGEs in such structural alteration and induction of fibrillation remains undefined. In this study, we determined the specific AGEs mediated structural modifications in albumin mainly considering carboxymethyllysine (CML), carboxyethyllysine (CEL), and argpyrimidine (Arg-P) which are the major AGEs formed in the body. We studied the secondary structural changes based on circular dichroism (CD) and spectroscopic analysis. The AGEs induced fibrillation was determined by Congo red binding and examination of scanning and transmission electron micrographs. The amyloidogenic regions in the sequence of BSA were determined using FoldAmyloid. It was observed that CEL modification of BSA leads to the development of fibrillar structures, which was evident from both secondary structure changes and TEM analysis. PMID:27037764

  4. Receptor for Advanced Glycation End Products Regulates Adipocyte Hypertrophy and Insulin Sensitivity in Mice

    PubMed Central

    Monden, Masayo; Koyama, Hidenori; Otsuka, Yoshiko; Morioka, Tomoaki; Mori, Katsuhito; Shoji, Takuhito; Mima, Yohei; Motoyama, Koka; Fukumoto, Shinya; Shioi, Atsushi; Emoto, Masanori; Yamamoto, Yasuhiko; Yamamoto, Hiroshi; Nishizawa, Yoshiki; Kurajoh, Masafumi; Yamamoto, Tetsuya; Inaba, Masaaki

    2013-01-01

    Receptor for advanced glycation end products (RAGE) has been shown to be involved in adiposity as well as atherosclerosis even in nondiabetic conditions. In this study, we examined mechanisms underlying how RAGE regulates adiposity and insulin sensitivity. RAGE overexpression in 3T3-L1 preadipocytes using adenoviral gene transfer accelerated adipocyte hypertrophy, whereas inhibitions of RAGE by small interfering RNA significantly decrease adipocyte hypertrophy. Furthermore, double knockdown of high mobility group box-1 and S100b, both of which are RAGE ligands endogenously expressed in 3T3-L1 cells, also canceled RAGE-medicated adipocyte hypertrophy, implicating a fundamental role of ligands–RAGE ligation. Adipocyte hypertrophy induced by RAGE overexpression is associated with suppression of glucose transporter type 4 and adiponectin mRNA expression, attenuated insulin-stimulated glucose uptake, and insulin-stimulated signaling. Toll-like receptor (Tlr)2 mRNA, but not Tlr4 mRNA, is rapidly upregulated by RAGE overexpression, and inhibition of Tlr2 almost completely abrogates RAGE-mediated adipocyte hypertrophy. Finally, RAGE−/− mice exhibited significantly less body weight, epididymal fat weight, epididymal adipocyte size, higher serum adiponectin levels, and higher insulin sensitivity than wild-type mice. RAGE deficiency is associated with early suppression of Tlr2 mRNA expression in adipose tissues. Thus, RAGE appears to be involved in mouse adipocyte hypertrophy and insulin sensitivity, whereas Tlr2 regulation may partly play a role. PMID:23011593

  5. Soluble receptor for advanced glycation end products mitigates vascular dysfunction in spontaneously hypertensive rats.

    PubMed

    Liu, Yu; Yu, Manli; Zhang, Le; Cao, Qingxin; Song, Ying; Liu, Yuxiu; Gong, Jianbin

    2016-08-01

    Vascular dysfunction including vascular remodeling and endothelial dysfunction in hypertension often results in poor clinical outcomes and increased risk of vascular accidents. We investigate the effect of treatment with soluble receptor for advanced glycation end products (sRAGE) on vascular dysfunction in spontaneously hypertensive rats (SHR). Firstly, the aortic AGE/RAGE pathway was investigated in SHR. Secondly, SHR received intraperitoneal injections of sRAGE daily for 4 weeks. Effect of sRAGE against vascular dysfunction in SHR and underlying mechanism was investigated. SHR aortas exhibited enhanced activity of aldose reductase, reduced activity of glyoxalase 1, accumulation of methylglyoxal and AGE, and upregulated expression of RAGE. Treatment of SHR with sRAGE had no significant effect on blood pressure, but alleviated aortic hypertrophy and endothelial dysfunction. In vitro, treatment with sRAGE reversed the effect of incubation with AGE on proliferation of smooth muscle cells and endothelial function. Treatment of SHR with sRAGE abated oxidative stress, suppressed inflammation and NF-κB activation, improved the balance between Ang II and Ang-(1-7) through reducing angiotensin-converting enzyme (ACE) activity and enhancing ACE2 expression, and upregulated peroxisome proliferator-activated receptor gamma (PPAR-γ) expression in aortas. In conclusion, treatment with sRAGE alleviated vascular adverse remodeling in SHR, possibly via suppression of oxidative stress and inflammation, improvement in RAS balance, and activation of PPAR-γ pathway. PMID:27426491

  6. Effect of taurine on advanced glycation end products-induced hypertrophy in renal tubular epithelial cells

    SciTech Connect

    Huang, J.-S. Chuang, L.-Y.; Guh, J.-Y.; Yang, Y.-L.; Hsu, M.-S.

    2008-12-01

    Mounting evidence indicates that advanced glycation end products (AGE) play a major role in the development of diabetic nephropathy (DN). Taurine is a well documented antioxidant agent. To explore whether taurine was linked to altered AGE-mediated renal tubulointerstitial fibrosis in DN, we examined the molecular mechanisms of taurine responsible for inhibition of AGE-induced hypertrophy in renal tubular epithelial cells. We found that AGE (but not non-glycated BSA) caused inhibition of cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, bcl-2 protein expression, and mitochondrial cytochrome c release in BSA, AGE, or the antioxidant taurine treatments in these cells. AGE-induced the Raf-1/extracellular signal-regulated kinase (ERK) activation was markedly blocked by taurine. Furthermore, taurine, the Raf-1 kinase inhibitor GW5074, and the ERK kinase inhibitor PD98059 may have the ability to induce cellular proliferation and cell cycle progression from AGE-treated cells. The ability of taurine, GW5074, or PD98059 to inhibit AGE-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of RAGE, p27{sup Kip1}, collagen IV, and fibronectin. The results obtained in this study suggest that taurine may serve as the potential anti-fibrotic activity in DN through mechanism dependent of its Raf-1/ERK inactivation in AGE-induced hypertrophy in renal tubular epithelial cells.

  7. The receptor for advanced glycation end products mediates lung endothelial activation by RBCs

    PubMed Central

    Friedman, Jessica L.; Wang, Liang-Chuan; Stolz, Donna; Muthukumaran, Geetha; Siegel, Don L.; Schmidt, Ann Marie; Lee, Janet S.; Albelda, Steven M.

    2013-01-01

    The receptor for advanced glycation end products (RAGE) is a multiligand pattern recognition receptor implicated in multiple disease states. Although RAGE is expressed on systemic vascular endothelium, the expression and function of RAGE on lung endothelium has not been studied. Utilizing in vitro (human) and in vivo (mouse) models, we established the presence of RAGE on lung endothelium. Because RAGE ligands can induce the expression of RAGE and stored red blood cells express the RAGE ligand Nε-carboxymethyl lysine, we investigated whether red blood cell (RBC) transfusion would augment RAGE expression on endothelium utilizing a syngeneic model of RBC transfusion. RBC transfusion not only increased lung endothelial RAGE expression but enhanced lung inflammation and endothelial activation, since lung high mobility group box 1 and vascular cell adhesion molecule 1 expression was elevated following transfusion. These effects were mediated by RAGE, since endothelial activation was absent in RBC-transfused RAGE knockout mice. Thus, RAGE is inducibly expressed on lung endothelium, and one functional consequence of RBC transfusion is increased RAGE expression and endothelial activation. PMID:23275625

  8. Olive Leaf Extracts Are a Natural Source of Advanced Glycation End Product Inhibitors

    PubMed Central

    Charisiadis, Pantelis; Margianni, Evangelia; Lamari, Fotini N.; Gerothanassis, Ioannis P.

    2013-01-01

    Abstract Advanced glycation end products (AGEs), which are readily formed and accumulated with sustained hyperglycemia, contribute to the development of diabetic complications. As a consequence, inhibition of AGE formation constitutes an attractive therapeutic/preventive target. In the current study, we explored the phytochemical composition and the in vitro effect of two different olive leaf extracts (an aqueous and a methanolic) on AGE formation. The methanolic olive leaf extract inhibited fluorescent AGE formation in a bovine serum albumin (BSA)-ribose system, whereas the aqueous extract had no effect in both BSA-fructose and BSA-ribose systems. The phytochemical profile was investigated with liquid chromatography-ultraviolet-visible (UV-Vis) diode array coupled to electrospray ionization multistage mass spectrometry (LC/DAD/ESI-MSn). Quantification of the major phenolic compounds was performed with high performance liquid chromatography with UV-Vis diode array detection and nuclear magnetic resonance spectroscopy. Among the major phenolic components (luteolin, hydroxytyrosol, luteolin-4′-O-β-D-glucopyranoside, luteolin-7-O-β-D-glucopyranoside, and oleuropein), luteolin and luteolin-4′-O-β-D-glucopyranoside were assigned as potent inhibitors of AGE formation. The extraction procedure greatly affects the composition and therefore the anti-glycation potential of olive leaves. PMID:24044491

  9. The receptor for advanced glycation end products is a central mediator of asthma pathogenesis.

    PubMed

    Milutinovic, Pavle S; Alcorn, John F; Englert, Judson M; Crum, Lauren T; Oury, Tim D

    2012-10-01

    The receptor for advanced glycation end products (RAGE) is a multiligand receptor that has been shown to contribute to the pathogenesis of diabetes, atherosclerosis, and neurodegeneration. However, its role in asthma and allergic airway disease is largely unknown. These studies use a house dust mite (HDM) mouse model of asthma/allergic airway disease. Respiratory mechanics were assessed and compared between wild-type and RAGE knockout mice. Bronchovascular architecture was assessed with quantitative scoring, and expression of RAGE, immunoglobulins, and relevant cytokines was assessed by standard protein detection methods and/or quantitative RT-PCR. The absence of RAGE abolishes most assessed measures of pathology, including airway hypersensitivity (resistance, tissue damping, and elastance), eosinophilic inflammation, and airway remodeling. IL-4 secretion, isotype class switching, and antigen recognition are intact in the absence of RAGE. In contrast, normal increases in IL-5, IL-13, eotaxin, and eotaxin-2 production are abrogated in the RAGE knockouts. IL-17 indicates complex regulation, with elevated baseline expression in RAGE knockouts, but no induction in response to allergen. Treatment of WT mice with an inhibitor of RAGE markedly reduces inflammation in the HDM model, suggesting that RAGE inhibition may serve as a promising therapeutic strategy. Finally, the results in the HDM model are recapitulated in an ovalbumin model of asthma, suggesting that RAGE plays a role in asthma irrespective of the identity of the allergens involved. PMID:22889845

  10. Olive leaf extracts are a natural source of advanced glycation end product inhibitors.

    PubMed

    Kontogianni, Vassiliki G; Charisiadis, Pantelis; Margianni, Evangelia; Lamari, Fotini N; Gerothanassis, Ioannis P; Tzakos, Andreas G

    2013-09-01

    Advanced glycation end products (AGEs), which are readily formed and accumulated with sustained hyperglycemia, contribute to the development of diabetic complications. As a consequence, inhibition of AGE formation constitutes an attractive therapeutic/preventive target. In the current study, we explored the phytochemical composition and the in vitro effect of two different olive leaf extracts (an aqueous and a methanolic) on AGE formation. The methanolic olive leaf extract inhibited fluorescent AGE formation in a bovine serum albumin (BSA)-ribose system, whereas the aqueous extract had no effect in both BSA-fructose and BSA-ribose systems. The phytochemical profile was investigated with liquid chromatography-ultraviolet-visible (UV-Vis) diode array coupled to electrospray ionization multistage mass spectrometry (LC/DAD/ESI-MS(n)). Quantification of the major phenolic compounds was performed with high performance liquid chromatography with UV-Vis diode array detection and nuclear magnetic resonance spectroscopy. Among the major phenolic components (luteolin, hydroxytyrosol, luteolin-4'-O-β-D-glucopyranoside, luteolin-7-O-β-D-glucopyranoside, and oleuropein), luteolin and luteolin-4'-O-β-D-glucopyranoside were assigned as potent inhibitors of AGE formation. The extraction procedure greatly affects the composition and therefore the anti-glycation potential of olive leaves. PMID:24044491

  11. The Receptor for Advanced Glycation End Products Activates the AIM2 Inflammasome in Acute Pancreatitis.

    PubMed

    Kang, Rui; Chen, Ruochan; Xie, Min; Cao, Lizhi; Lotze, Michael T; Tang, Daolin; Zeh, Herbert J

    2016-05-15

    Severe acute pancreatitis (AP) is responsible for significant human morbidity and mortality worldwide. Currently, no specific treatments for AP exist, primarily due to the lack of a mechanistic understanding of sterile inflammation and the resultant multisystem organ dysfunction, the pathologic response of AP linked to early death. In this study, we demonstrate that the class III major histocompatibility region III receptor for advanced glycation end products (RAGE) contributes to AP by modulating inflammasome activation in macrophages. RAGE mediated nucleosome-induced absent in melanoma 2 (but not NLRP3) inflammasome activation by modulating dsRNA-dependent protein kinase phosphorylation in macrophages. Pharmacological and genetic inhibition of the RAGE-dsRNA-dependent protein kinase pathway attenuated the release of inflammasome-dependent exosomal leaderless cytokines (e.g., IL-1β and high-mobility group box 1) in vitro. RAGE or absent in melanoma 2 depletion in mice limited tissue injury, reduced systemic inflammation, and protected against AP induced by l-arginine or cerulein in experimental animal models. These findings define a novel role for RAGE in the propagation of the innate immune response with activation of the nucleosome-mediated inflammasome and will help guide future development of therapeutic strategies to treat AP. PMID:27045109

  12. Advanced glycation end products (AGEs) promote melanogenesis through receptor for AGEs

    PubMed Central

    Lee, Eun Jung; Kim, Ji Young; Oh, Sang Ho

    2016-01-01

    Accumulation of advanced glycation end products (AGEs) is linked with development or aggravation of many degenerative processes or disorders, including aging and atherosclerosis. AGEs production in skin cells is known to promote stiffness and loss of elasticity through their buildup in connective tissue. However, the impact of AGEs has yet to be fully explored in melanocytes. In this study, we confirmed the existence of receptor for AGE (RAGE) in melanocytes in western blot and immunofluorescence along with increased melanin production in ex vivo skin organ culture and in vitro melanocyte culture following AGEs treatment. Cyclic AMP response element-binding protein (CREB) and extracellular signal-regulated kinases (ERK) 1/2 are considered as key regulatory proteins in AGEs-induced melanogenesis. In addition, blockage experiment using anti-RAGE blocking antibody has indicated that RAGE plays a pivotal role in AGE-mediated melanogenesis. Therefore, it is apparent that AGEs, known markers of aging, promote melanogenesis via RAGE. In addition, AGEs could be implicated in pigmentation associated with photoaging according to the results of increased secretion of AGEs from keratinocytes following UV irradiation. AGE-mediated melanogenesis may thus hold promise as a novel mean of altering skin pigmentation. PMID:27293210

  13. Advanced Glycation End-Products Enhance Lung Cancer Cell Invasion and Migration.

    PubMed

    Hsia, Te-Chun; Yin, Mei-Chin; Mong, Mei-Chin

    2016-01-01

    Effects of carboxymethyllysine (CML) and pentosidine, two advanced glycation end-products (AGEs), upon invasion and migration in A549 and Calu-6 cells, two non-small cell lung cancer (NSCLC) cell lines were examined. CML or pentosidine at 1, 2, 4, 8 or 16 μmol/L were added into cells. Proliferation, invasion and migration were measured. CML or pentosidine at 4-16 μmol/L promoted invasion and migration in both cell lines, and increased the production of reactive oxygen species, tumor necrosis factor-α, interleukin-6 and transforming growth factor-β1. CML or pentosidine at 2-16 μmol/L up-regulated the protein expression of AGE receptor, p47(phox), intercellular adhesion molecule-1 and fibronectin in test NSCLC cells. Matrix metalloproteinase-2 protein expression in A549 and Calu-6 cells was increased by CML or pentosidine at 4-16 μmol/L. These two AGEs at 2-16 μmol/L enhanced nuclear factor κ-B (NF-κ B) p65 protein expression and p38 phosphorylation in A549 cells. However, CML or pentosidine at 4-16 μmol/L up-regulated NF-κB p65 and p-p38 protein expression in Calu-6 cells. These findings suggest that CML and pentosidine, by promoting the invasion, migration and production of associated factors, benefit NSCLC metastasis. PMID:27517907

  14. Advanced glycation end-products and skin autofluorescence in end-stage renal disease: a review.

    PubMed

    Arsov, Stefan; Graaff, Reindert; van Oeveren, Wim; Stegmayr, Bernd; Sikole, Aleksandar; Rakhorst, Gerhard; Smit, Andries J

    2014-01-01

    Chronic kidney disease (CKD), especially in its end stage, is marked by extremely high cardiovascular rates of morbidity and mortality; hemodialysis patients have a five-fold shorter life expectancy than healthy subjects of the same age. In CKD the metabolic products that accumulate in the body are so-called uremic toxins. These include advanced glycation end-products (AGE). AGE levels are markedly increased in CKD patients not only because of impaired excretion but also because of increased production. AGE formation has initially been described as a non-enzymatic reaction between proteins and glucose in the so-called Maillard reaction, but they are also more rapidly formed during oxidative stress and subsequent formation of reactive carbonyl compounds like (methyl)glyoxal. AGE accumulate in tissue where they cross-link with proteins, e.g., collagen, inducing tissue stiffening of blood vessels and skin. They may also interact with receptor of AGE (RAGE) and other receptors, which lead to activation of intracellular transduction mechanisms resulting in cytokine release and further tissue damage in CKD. The accumulation of AGE in the skin can be measured non-invasively using autofluorescence. The skin autofluorescence is a strong marker of cardiovascular mortality in CKD. The focus of this review is on the role of tissue and plasma AGE, and of skin autofluorescence as a proxy of tissue AGE accumulation, in the increase in cardiovascular disease in end stage renal disease (ESRD). This review will also present the possibility of reducing the AGE accumulation in ESRD patients using the following five methods: 1) use of low AGE peritoneal dialysis solutions; 2) use of advanced hemodialysis techniques; 3) use of AGE reducing drugs; 4) optimizing the nutrition of hemodialysis patients; and 5) renal transplantation. PMID:23612551

  15. Pathologic role of dietary advanced glycation end products in cardiometabolic disorders, and therapeutic intervention.

    PubMed

    Yamagishi, Sho-Ichi; Matsui, Takanori

    2016-02-01

    Reactive derivatives from nonenzymatic glucose-protein condensation reactions, as well as lipids and nucleic acids exposed to reducing sugars, form a heterogeneous group of irreversible adducts called AGEs (advanced glycation end products). The glycation process begins with the conversion of reversible Schiff base adducts to more stable, covalently bound Amadori rearrangement products. Over the course of days to weeks, these Amadori products undergo further rearrangement and condensation reactions to form irreversibly cross-linked macroprotein derivatives known as AGEs. The formation and accumulation of AGEs have been known to progress in a physiological aging process and at an accelerated rate under hyperglycemic and oxidative stress conditions. There is growing evidence that AGEs play a pathologic role in numerous disorders. Indeed, glycation and/or cross-linking modification of circulating or organic matrix proteins by AGEs the senescence of moieties and deteriorate their physiological function and structural integrity in multiple organ systems. Moreover, AGEs elicit oxidative stress and inflammatory reactions through the interaction with the receptor for advanced glycation products in a variety of cells, thereby contributing to the development and progression of various aging- or diabetes-related disorders, such as cardiovascular disease, chronic kidney disease, insulin resistance, and Alzheimer's disease. Recently, diet has been recognized as a major environmental source of AGEs that could cause proinflammatory reactions and organ damage in vivo. Therefore, this review summarizes the pathophysiological role of dietary AGEs in health and disease, especially focusing on cardiometabolic disorders. We also discuss the potential utility in targeting exogenously derived AGEs for therapeutic intervention. PMID:26602289

  16. Advanced glycation end products as environmental risk factors for the development of type 1 diabetes.

    PubMed

    Yap, Felicia Y T; Kantharidis, Phillip; Coughlan, Melinda T; Slattery, Robyn; Forbes, Josephine M

    2012-04-01

    The globally rising incidence of Type 1 diabetes (T1D) is no longer restricted to individuals with higher risk genotypes, but is now significantly increasing in a population with lower risk genotypes, likely as the result of environmental factors. In this review, we discuss the potential of advanced glycation end products (AGEs) as environmental contributors to the development of T1D. AGEs are nonenzymatically formed protein modifications found in the body, as well as, consumed in our daily diets. To date, many studies have provided evidence of AGE involvement in β cell dysfunction, whether by AGE modification itself or via interaction with AGE receptors. The receptor for AGE (RAGE) and AGE-receptor-1 (AGE-R1) are of particular interest, given that studies have demonstrated the deleterious effects of RAGE modulation and the protection afforded by AGE-R1 in the context of diabetes. More interestingly, we have recently found that two RAGE polymorphism are predictive of T1D in humans while the third is protective. Moreover, soluble RAGE (sRAGE) levels (a circulating competitive inhibitor of RAGE) were greatly reduced at seroconversion to autoantibodies in both children on high risk of T1D background and in an animal model of autoiummune diabetes. Taken together with the fact that AGEs have also shown to be involved in immunomodulation, it is tempting to postulate that dietary AGEs, RAGE and even AGE-R1 could be working synergistically or independently to breach the tightly regulated immune system, providing a missing link in the development of T1D. PMID:22250649

  17. Soluble receptor for advanced glycation end products and increased aortic stiffness in the general population.

    PubMed

    Mayer, Otto; Seidlerová, Jitka; Filipovský, Jan; Vágovičová, Petra; Wohlfahrt, Peter; Cífková, Renata; Windrichová, Jindra; Topolčan, Ondřej

    2016-04-01

    It has been suggested that accumulation of advanced glycation end products (AGEs) is involved in several pathophysiological processes in the vessel wall. We hypothesized that low levels of the soluble receptor for AGEs (sRAGE) might be associated with increased arterial stiffness, a manifestation of vascular ageing in the general population. Using a cross-sectional design, we analyzed 1077 subjects from the Czech post-MONICA study. The aortic pulse wave velocity (aPWV) was measured using a Sphygmocor device. sRAGE concentrations were assessed in frozen samples using enzyme-linked immunosorbent assay methods (R&D Systems). aPWV significantly (P<0.0001) increased across the sRAGE quartiles. An aPWV of 1 m s(-1) was associated with a 37% increase in the risk of low sRAGE (<918 pg ml(-1), bottom quartile; P-value=0.018). In a categorized manner, subjects in the bottom sRAGE quartile had an odds ratio of an increased aPWV (⩾9.3 m s(-1)), adjusted for all potential confounders of 2.05 (95% confidence interval: 1.26-3.32; P=0.004), but this was only the case for non-diabetic hypertensive patients. In contrast, a low sRAGE was rejected as an independent predictor of an increased aPWV in normotensive or diabetic subjects using similar regression models. In conclusion, low circulating sRAGE was independently associated with increased arterial stiffness in a general population-based sample, but this was only observed in hypertensive non-diabetic patients. PMID:26631850

  18. Receptor for Advanced Glycation End Products (RAGE) Serves a Protective Role during Klebsiella pneumoniae - Induced Pneumonia.

    PubMed

    Achouiti, Ahmed; de Vos, Alex F; van 't Veer, Cornelis; Florquin, Sandrine; Tanck, Michael W; Nawroth, Peter P; Bierhaus, Angelika; van der Poll, Tom; van Zoelen, Marieke A D

    2016-01-01

    Klebsiella species is the second most commonly isolated gram-negative organism in sepsis and a frequent causative pathogen in pneumonia. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory responses. We here aimed to investigate the role of RAGE in the host response to Klebsiella (K.) pneumoniae pneumonia and intransally inoculated rage gene deficient (RAGE-/-) and normal wild-type (Wt) mice with K. pneumoniae. Klebsiella pneumonia resulted in an increased pulmonary expression of RAGE. Furthermore, the high-affinity RAGE ligand high mobility group box-1 was upregulated during K. pneumoniae pneumonia. RAGE deficiency impaired host defense as reflected by a worsened survival, increased bacterial outgrowth and dissemination in RAGE-/- mice. RAGE-/- neutrophils showed a diminished phagocytosing capacity of live K. pneumoniae in vitro. Relative to Wt mice, RAGE-/- mice demonstrated similar lung inflammation, and slightly elevated-if any-cytokine and chemokine levels and unchanged hepatocellular injury. In addition, RAGE-/- mice displayed an unaltered response to intranasally instilled Klebsiella lipopolysaccharide (LPS) with respect to pulmonary cell recruitment and local release of cytokines and chemokines. These data suggest that (endogenous) RAGE protects against K. pneumoniae pneumonia. Also, they demonstrate that RAGE contributes to an effective antibacterial defense during K. pneumoniae pneumonia, at least partly via its participation in the phagocytic properties of professional granulocytes. Additionally, our results indicate that RAGE is not essential for the induction of a local and systemic inflammatory response to either intact Klebsiella or Klebsiella LPS. PMID:26824892

  19. Paradoxical function for the receptor for advanced glycation end products in mouse models of pulmonary fibrosis

    PubMed Central

    Englert, Judson M; Kliment, Corrine R; Ramsgaard, Lasse; Milutinovic, Pavle S; Crum, Lauren; Tobolewski, Jacob M; Oury, Tim D

    2011-01-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive disease with poor survival. The identification of therapeutic targets is essential to improving outcomes. Previous studies found that expression of the receptor for advanced glycation end products (RAGE) in the lung is significantly decreased in human IPF lungs and in two animal models of pulmonary fibrosis. In addition, RAGE-null mice spontaneously develop pulmonary fibrosis with age and more severe fibrosis when challenged with asbestos. In contrast to the findings that the lack of RAGE enhanced pulmonary fibrosis, He et al. found that RAGE null mice were protected from bleomycin-induced fibrosis and suggested the effect was due to a lack of HMGB1 induced RAGE signaling. The current study further tests this hypothesis by blocking RAGE signaling via administration of soluble RAGE, a decoy receptor, to determine if this will also protect against pulmonary fibrosis. Wild-type, RAGE+/-, and RAGE-/- mice were treated with bleomycin and assessed for fibrosis. Wild-type mice were also treated with exogenous soluble RAGE or vehicle control. In addition, in vitro studies with primary alveolar epithelial cells from wild-type and RAGE null mice were used to investigate the effect of RAGE on cell viability and migration in response to injury. A lack of RAGE was found to be protective against bleomycin injury in both in vivo and in vitro studies. However, soluble RAGE administration was unable to ameliorate fibrosis. This study confirms paradoxical responses to two different models of pulmonary fibrosis and suggests a further role for RAGE in cellular migration. PMID:21487520

  20. Advanced Glycation End-Products affect transcription factors regulating insulin gene expression

    SciTech Connect

    Puddu, A.; Storace, D.; Odetti, P.; Viviani, G.L.

    2010-04-23

    Advanced Glycation End-Products (AGEs) are generated by the covalent interaction of reducing sugars with proteins, lipids or nucleic acids. AGEs are implicated in diabetic complications and pancreatic {beta}-cell dysfunction. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T15 to high concentrations of AGEs leads to a significant decrease of insulin secretion and content. Insulin gene transcription is positively regulated by the beta cell specific transcription factor PDX-1 (Pancreatic and Duodenal Homeobox-1). On the contrary, the forkhead transcription factor FoxO1 inhibits PDX-1 gene transcription. Activity of FoxO1 is regulated by post-translational modifications: phosphorylation deactivates FoxO1, and acetylation prevents FoxO1 ubiquitination. In this work we investigated whether AGEs affect expression and subcellular localization of PDX-1 and FoxO1. HIT-T15 cells were cultured for 5 days in presence of AGEs. Cells were then lysed and processed for subcellular fractionation. We determined intracellular insulin content, then we assessed the expression and subcellular localization of PDX-1, FoxO1, phosphoFoxO1 and acetylFoxO1. As expected intracellular insulin content was lower in HIT-T15 cells cultured with AGEs. The results showed that AGEs decreased expression and nuclear localization of PDX-1, reduced phosphorylation of FoxO1, and increased expression and acetylation of FoxO1. These results suggest that AGEs decrease insulin content unbalancing transcription factors regulating insulin gene expression.

  1. Advanced glycation end products biphasically modulate bone resorption in osteoclast-like cells.

    PubMed

    Li, Ziqing; Li, Chaohong; Zhou, Yuhuan; Chen, Weishen; Luo, Guotian; Zhang, Ziji; Wang, Haixing; Zhang, Yangchun; Xu, Dongliang; Sheng, Puyi

    2016-03-01

    Advanced glycation end products (AGEs) disturb bone remodeling during aging, and this process is accelerated in diabetes. However, their role in modulation of osteoclast-induced bone resorption is controversial, with some studies indicating that AGEs enhance bone resorption and others showing the opposite effect. We determined whether AGEs present at different stages of osteoclast differentiation affect bone resorption differently. Based on increased levels of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK), we identified day 4 of induction as the dividing time of cell fusion stage and mature stage in RAW264.7 cell-derived osteoclast-like cells (OCLs). AGE-modified BSA (50-400 μg/ml) or control BSA (100 μg/ml) was then added at the beginning of each stage. Results showed that the presence of AGEs at the cell fusion stage reduced pit numbers, resorption area, and CTSK expression. Moreover, expression of receptor activator of nuclear factor-κB (RANK) as well as the number of TRAP-positive cells, nuclei per OCL, actin rings, and podosomes also decreased. However, the presence of AGEs at the mature stage enlarged the resorption area markedly and increased pit numbers slightly. Intriguingly, only the number of nuclei per OCL and podosomes increased. These data indicate that AGEs biphasically modulate bone resorption activity of OCLs in a differentiation stage-dependent manner. AGEs at the cell fusion stage reduce bone resorption dramatically, mainly via suppression of RANK expression in osteoclast precursors, whereas AGEs at the mature stage enhance bone resorption slightly, most likely by increasing the number of podosomes in mature OCLs. PMID:26670486

  2. Soluble receptor for advanced glycation end-products and progression of airway disease

    PubMed Central

    2014-01-01

    Background The receptor for advanced glycation end-products (RAGE) is highly expressed in the lung, where it is believed to have a homeostatic role. Reduced plasma levels of soluble RAGE (sRAGE) have been reported in patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to evaluate the association of plasma sRAGE levels with a longitudinal decline of lung function. We have also measured plasma levels of high mobility group box 1 (HMGB1), a RAGE ligand which has been associated with chronic inflammatory diseases including COPD. Methods Baseline plasma concentrations of sRAGE and HMGB1 were measured in non-smokers (n = 32), smokers without COPD (n = 212), and smokers with COPD (n = 51), and the associations of the plasma sRAGE and HMGB1 levels with longitudinal declines of lung function during a 4-year follow-up period were analysed. Results The plasma levels of sRAGE were significantly lower in smokers without COPD and in smokers with COPD, as compared to those of non-smokers. Plasma sRAGE levels positively correlated with FVC and FEV1 and inversely correlated with BMI and pack-years. Lower sRAGE levels were associated with greater declines of FEV1/FVC over 4 years in all participants. Moreover, multivariate regression analysis indicated that the baseline plasma sRAGE concentration was an independent predictor of FEV1/FVC decline in all groups. A subgroup analysis showed that decreased sRAGE levels are significantly associated with a more rapid decline of FEV1/FVC in smokers with COPD. There was no significant correlation between plasma HMGB1 levels and longitudinal decline of lung function. Conclusions Lower plasma concentrations of sRAGE were associated with greater progression of airflow limitations over time, especially in smokers with COPD, suggesting that RAGE might have a protective role in the lung. PMID:24758342

  3. Epicatechin breaks preformed glycated serum albumin and reverses the retinal accumulation of advanced glycation end products.

    PubMed

    Kim, Junghyun; Kim, Chan-Sik; Moon, Min Kyong; Kim, Jin Sook

    2015-02-01

    The accumulation of advanced glycation end products (AGEs) is associated with many of the complications of diabetes mellitus, including diabetic retinopathy. AGE-breakers, such as N-phenacylthiazolium and alagebrium, have been proposed as therapeutic agents for reversing the increase in protein crosslinking in diabetes. (-)-Epicatechin is a major dietary flavonoid with a wide range of health-promoting biological activities. The aim of this study was to determine the potential effect of (-)-epicatechin in reducing the burden of AGEs in vitro and in vivo and to evaluate whether the reduced AGE burden could translate into improvement in retinal vascular function in exogenously AGE-injected rats. Glycated human serum albumin was purified from patients with diabetes. The breakdown of the already formed AGEs was studied by treating glycated human serum albumin with (-)-epicatechin. To study the effect of (-)-epicatechin on retinal vascular function, exogenously AGE-injected rats were treated with (-)-epicatechin (50 and 100 mg/kg i.p.) for two weeks. Apoptosis of retinal vascular cells was quantified using TUNEL staining. The AGE load in the retinas was determined via immunohistochemical staining and western blot analysis. (-)-Epicatechin was able to break preformed glycated human serum albumin in vitro as well as reduce AGE accumulation in retinas in vivo in a dose dependent manner. In exogenously AGE-injected rats, treatment with (-)-epicatechin was evidenced by an improved retinal vascular apoptosis. AGE burden in retinas was also reduced upon treatment. This study suggests that (-)-epicatechin could represent a valuable drug for the treatment of diabetic retinopathy by reducing the AGE burden. PMID:25530268

  4. Bone-targeting endogenous secretory receptor for advanced glycation end products rescues rheumatoid arthritis.

    PubMed

    Takahashi, Tatsuo; Katsuta, Sayaka; Tamura, Yusuke; Nagase, Nozomi; Suzuki, Keita; Nomura, Masaaki; Tomatsu, Shunji; Miyamoto, Ken-Ichi; Kobayashi, Shinjiro

    2013-01-01

    Rheumatoid arthritis (RA) is a chronic inflammatory synovitis that leads to the destruction of bone and cartilage. The receptor for advanced glycation end products (RAGE) is a multiligand membrane-bound receptor for high-mobility group box-1 (HMGB1) associated with development of RA by inducing production of proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1 and IL-6. We developed a bone-targeting therapeutic agent by tagging acidic oligopeptide to a nonmembrane-bound form of RAGE (endogenous secretory RAGE [esRAGE]) functioning as a decoy receptor. We assessed its tissue distribution and therapeutic effectiveness in a murine model of collagen-induced arthritis (CIA). Acidic oligopeptide-tagged esRAGE (D6-esRAGE) was localized to mineralized region in bone, resulting in the prolonged retention of more than 1 wk. Weekly administration of D6-esRAGE with a dose of 1 mg/kg to RA model mice significantly ameliorated inflammatory arthritis, synovial hyperplasia, cartilage destruction and bone destruction, while untagged esRAGE showed little effectiveness. Moreover, D6-esRAGE reduced plasma levels of proinflammatory cytokines including TNF-α, IL-1 and IL-6, while esRAGE reduced the levels of IL-1 and IL-6 to a lesser extent, suggesting that production of IL-1 and IL-6 reduced along the blockade of HMGB1 receptor downstream signals by D6-esRAGE could be attributed to remission of CIA. These findings indicate that D6-esRAGE enhances drug delivery to bone, leading to rescue of clinical and pathological lesions in murine CIA. PMID:23821362

  5. Recombinant advanced glycation end product receptor pharmacokinetics in normal and diabetic rats.

    PubMed

    Renard, C; Chappey, O; Wautier, M P; Nagashima, M; Lundh, E; Morser, J; Zhao, L; Schmidt, A M; Scherrmann, J M; Wautier, J L

    1997-07-01

    Vascular dysfunction in patients with diabetes mellitus is related to advanced glycation end product (AGE) formation. We previously showed that AGEs produce an increase in vascular permeability and generated an oxidant stress after binding to the receptor (RAGE) present on endothelium. RAGE, a 35-kDa protein that belongs to the immunoglobulin superfamily, has been cloned from a rat lung cDNA library, and recombinant rat soluble RAGE (rR-RAGE) has been produced in insect cells. The sequence of RAGE is highly conserved between human and rat. We studied the biological effect of rR-RAGE and pharmacokinetics of 125I-rR-RAGE after intravenous or intraperitoneal administration in normal and streptozotocin-induced diabetic rats. rR-RAGE prevented albumin or inulin transfer through a bovine aortic endothelial cell monolayer, restored the hyperpermeability observed in diabetic rats or induced in normal rats by diabetic rat red blood cells, and corrected the reactive oxygen intermediate production after intravenous or intraperitoneal administration. After intravenous injection of 125I-rR-RAGE, the distribution half-life was longer (p < or = 0.01) in diabetic (0.15 and 4.01 hr) than in normal (0.02 and 0.21 hr) rats, as was the case for the elimination half-lives (diabetic, 57.17 hr; normal, 26.02 hr; p < or = 0.01). Distribution volume was higher in diabetic than in normal rats (6.94 and 3.24 liter/kg, respectively; p = 0.049). Our study showed that rR-RAGE was biologically active in vivo and slowly cleared, which suggests it could be considered as a potential therapy. PMID:9224812

  6. Garlic decreases liver and kidney receptor for advanced glycation end products expression in experimental diabetes.

    PubMed

    Al-Qattan, Khaled K; Mansour, Mohamed H; Thomson, Martha; Ali, Muslim

    2016-06-01

    The up-regulation of the receptor for advanced glycation end products (RAGE) has been implicated as a major mediator in the development and progression of diabetic nephropathy and hepatic fibrogenesis. The present study was designed to investigate the potential of garlic (Allium sativum L.) to modulate the level of expression of RAGE in renal and hepatic tissues of diabetic rats. Three groups of rats were studied after 8 weeks following diabetes induction: normal, streptozotocin-induced diabetic (control diabetic), and garlic-treated diabetic rats. A polyclonal antibody of proven specificity to RAGE indicated in immunohistochemical assays that RAGE labeling was significantly increased in renal and hepatic tissues of control diabetic rats compared to the normal group. The increased RAGE labeling involved mesangial cells in glomeruli exhibiting signs of mesangial expansion, mesangial nodule formation and glomerulosclerosis. In the liver, a significant up-regulation of RAGE was observed in hepatocytes and bile ducts and vessels in portal tracts. In 2-dimensional Western blots, RAGE expression in both tissues was dominated by heterogeneous charge variants, represented by 46-50kDa isoforms with more basic pIs compared to their counterparts in normal rats. Compared to control diabetic rats, RAGE labeling in the garlic-treated diabetic group was significantly reduced throughout renal and hepatic regions and was marked by the expression of 43-50kDa acidic charge variants comparable to those observed in normal rats. The capacity of garlic to modulate diabetes-induced up-regulation of selective RAGE polymorphic variants may be implicated in attenuating the detrimental consequences of excessive RAGE signaling manifested by diabetes-associated disorders. PMID:26968224

  7. A receptor-based bioadsorbent to target advanced glycation end products in chronic kidney disease.

    PubMed

    Zhang, Yangrong; Lapidos, Karen A; Gal-Moscovici, Anca; Sprague, Stuart M; Ameer, Guillermo A

    2014-06-01

    The accumulation of advanced glycation end products (AGEs) has been reported to be a major contributor to chronic systemic inflammation. AGEs are not efficiently removed by hemodialysis or the kidney of a chronic kidney disease (CKD) patient. The goal of this study was to develop a receptor for AGEs (RAGE)-based bioadsorbent device that was capable of removing endogenous AGEs from human blood. The extracellular domain of RAGE was immobilized onto agarose beads to generate the bioadsorbent. The efficacy of AGE removal from saline, serum, and whole blood; biological effects of AGE reduction; and hemocompatibility and stability of the bioadsorbent were investigated. The bioadsorbent bound AGE-modified bovine serum albumin (AGE-BSA) with a binding capacity of 0.73 ± 0.07 mg AGE-BSA/mL bioadsorbent. The bioadsorbent significantly reduced the concentration of total AGEs in serum isolated from end-stage kidney disease patients by 57%. AGE removal resulted in a significant reduction of vascular cell adhesion molecule-1 expression in human endothelial cells and abolishment of osteoclast formation in osteoclast progenitor cells. A hollow fiber device loaded with bioadsorbent-reduced endogenous AGEs from recirculated blood to 36% of baseline levels with no significant changes in total protein or albumin concentration. The bioadsorbent maintained AGE-specific binding capacity after freeze-drying and storage for 1 year. This approach provides the foundation for further development of soluble RAGE-based extracorporeal therapies to selectively deplete serum AGEs from human blood and decrease inflammation in patients with diabetes and/or CKD. PMID:24206165

  8. Survey of the Distribution of a Newly Characterized Receptor for Advanced Glycation End Products in Tissues

    PubMed Central

    Brett, Jerold; Schmidt, Ann Marie; Yan, Shi Du; Zou, Yu Shan; Weidman, Elliott; Pinsky, David; Nowygrod, Roman; Neeper, Michael; Przysiecki, Craig; Shaw, Alan; Migheli, Antonio; Stern, David

    1993-01-01

    Advanced glycation end products (AGEs), the final products of nonenzymatic glycation and oxidation of proteins, are found in the plasma and accumulate in the tissues during aging and at an accelerated rate in diabetes. A novel integral membrane protein, termed receptor for AGE (RAGE), forms a central part of the cell surface binding site for AGEs. Using monospecific, polyclonal antibody raised to human recombinant and bovine RAGE, immunostaining of bovine tissues showed RAGE in the vasculature, endothelium, and smooth muscle cells and in mononuclear cells in the tissues. Consistent with these data, RAGE antigen and mRNA were identified in cultured bovine endothelium, vascular smooth muscle, and monocyte-derived macrophages. RAGE antigen was also visualized in bovine cardiac myocytes as well as in cultures of neonatal rat cardiac myocytes and in neural tissue where motor neurons, peripheral nerves, and a population of cortical neurons were positive. In situ hybridization confirmed the presence of RAGE mRNA in the tissues, and studies with rat PC12 pheochromocytes indicated that they provide a neuronal-related cell culture model for examining RAGE expression. Pathological studies of human atherosclerotic plaques showed infiltration of RAGE-expressing cells in the expanded intima. These results indicate that RAGE is present in multiple tissues and suggest the potential relevance of AGE-RAGE interactions for modulating properties of the vasculature as well as neural and cardiac function, prominent areas of involvement in diabetes and in the normal aging process. ImagesFigure 9Figure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8Figure 10 PMID:8256857

  9. Molten Globule of Hemoglobin Proceeds into Aggregates and Advanced Glycated End Products

    PubMed Central

    Iram, Afshin; Alam, Tauqeer; Khan, Javed M.; Khan, Taqi A.; Khan, Rizwan H.; Naeem, Aabgeena

    2013-01-01

    Conformational alterations of bovine hemoglobin (Hb) upon sequential addition of glyoxal over a range of 0–90% v/v were investigated. At 20% v/v glyoxal, molten globule (MG) state of Hb was observed by altered tryptophan fluorescence, high ANS binding, existence of intact heme, native-like secondary structure as depicted by far-UV circular dichroism (CD) and ATR-FTIR spectra as well as loss in tertiary structure as confirmed by near-UV CD spectra. In addition, size exclusion chromatography analysis depicted that MG state at 20% v/v glyoxal corresponded to expanded pre-dissociated dimers. Aggregates of Hb were detected at 70% v/v glyoxal. These aggregates of Hb had altered tryptophan environment, low ANS binding, exposed heme, increased β-sheet secondary structure, loss in tertiary structure, enhanced thioflavin T (ThT) fluorescence and red shifted Congo Red (CR) absorbance. On incubating Hb with 30% v/v glyoxal for 0–20 days, advanced glycation end products (AGEs) were detected on day 20. These AGEs were characterised by enhanced tryptophan fluorescence at 450 nm, exposure of heme, increase in intermolecular β-sheets, enhanced ThT fluorescence and red shift in CR absorbance. Comet assay revealed aggregates and AGEs to be genotoxic in nature. Scanning electron microscopy confirmed the amorphous structure of aggregates and branched fibrils of AGEs. The transformation of α-helix to β-sheet usually alters the normal protein to amyloidogenic resulting in a variety of protein conformational disorders such as diabetes, prion and Huntington's. PMID:23991043

  10. Role of advanced glycation end products in hypertension and atherosclerosis: therapeutic implications.

    PubMed

    Vasdev, Sudesh; Gill, Vicki; Singal, Pawan

    2007-01-01

    The vascular diseases, hypertension and atherosclerosis, affect millions of individuals worldwide, and account for a large number of deaths globally. A better understanding of the mechanism of these conditions will lead to more specific and effective therapies. Hypertension and atherosclerosis are both characterized by insulin resistance, and we suggest that this plays a major role in their etiology. The cause of insulin resistance is not known, but may be a result of a combination of genetic and lifestyle factors. In insulin resistance, alterations in glucose and lipid metabolism lead to the production of excess aldehydes including glyoxal and methylglyoxal. These aldehydes react non-enzymatically with free amino and sulfhydryl groups of amino acids of proteins to form stable conjugates called advanced glycation end products (AGEs). AGEs act directly, as well as via receptors to alter the function of many intra- and extracellular proteins including antioxidant and metabolic enzymes, calcium channels, lipoproteins, and transcriptional and structural proteins. This results in endothelial dysfunction, inflammation and oxidative stress. All these changes are characteristic of hypertension and atherosclerosis. Human and animal studies have demonstrated that increased AGEs are also associated with these conditions. A pathological role for AGEs is substantiated by studies showing that therapies that attenuate insulin resistance and/or lower AGEs, are effective in decreasing oxidative stress, lowering blood pressure, and attenuating atherosclerotic vascular changes. These interventions include lipoic acid and other antioxidants, AGE breakers or soluble receptors of AGEs, and aldehyde-binding agents like cysteine. Such therapies may offer alternative specific means to treat hypertension and atherosclerosis. An adjunct therapy may be to implement lifestyle changes such as weight reduction, regular exercise, smoking cessation, and increasing dietary intake of fruits and

  11. Calcitriol blunts the deleterious impact of advanced glycation end products on endothelial cells.

    PubMed

    Talmor, Yeela; Golan, Eliezer; Benchetrit, Sydney; Bernheim, Jacques; Klein, Osnat; Green, Janice; Rashid, Gloria

    2008-05-01

    Advanced glycation end products (AGEs), which are elevated in diabetic and uremic patients, may induce vascular dysfunctions, and calcitriol may improve the cardiovascular complications. Therefore, we examined whether calcitriol may modify the endothelial response to AGEs stimulation. Knowing the importance of nuclear factor-kappaB in endothelial inflammatory responses, the effect of AGEs and calcitriol on this pathway was also studied. Calcitriol was added to endothelial cells previously incubated with AGE-human serum albumin (HSA). AGE-HSA induced a decrease in endothelial nitric oxide synthase (eNOS) mRNA expression and enzyme activity. Addition of calcitriol to AGE-HSA-treated endothelial cells improved the decreased action of AGEs on the eNOS system. AGE-HSA increased the AGEs receptor mRNA and protein, which were both blunted by calcitriol. The parallel elevation of interleukin-6 mRNA in the presence of AGE-HSA was also blunted by calcitriol. The NF-kappaB-p65 DNA binding activity was enhanced and associated with a decrease in inhibitor kappaBalpha (IkappaBalpha) and an increase in phosphorylated (p)-IkappaBalpha levels. Addition of calcitriol blunted the AGEs-induced elevation of NF-kappaB-p65 DNA binding activity, a phenomenon related to an increased expression of IkappaBalpha. This increase was correlated to declined p-IkappaBalpha levels. The present results support the concept that calcitriol may act as a vascular protective agent counteracting the probable deleterious actions of AGEs on endothelial cell activities. PMID:18353875

  12. Targeting receptor for advanced glycation end products (RAGE) expression induces apoptosis and inhibits prostate tumor growth

    SciTech Connect

    Elangovan, Indira; Thirugnanam, Sivasakthivel; Chen, Aoshuang; Zheng, Guoxing; Bosland, Maarten C.; Kajdacsy-Balla, Andre; Gnanasekar, Munirathinam

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Targeting RAGE by RNAi induces apoptosis in prostate cancer cells. Black-Right-Pointing-Pointer Silencing RAGE expression abrogates rHMGB1 mediated cell proliferation. Black-Right-Pointing-Pointer Down regulation of RAGE by RNAi inhibits PSA secretion of prostate cancer cells. Black-Right-Pointing-Pointer Knock down of RAGE abrogates prostate tumor growth in vivo. Black-Right-Pointing-Pointer Disruption of RAGE expression in prostate tumor activates death receptors. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a key role in the progression of prostate cancer. However, the therapeutic potential of targeting RAGE expression in prostate cancer is not yet evaluated. Therefore in this study, we have investigated the effects of silencing the expression of RAGE by RNAi approach both in vitro and in vivo. The results of this study showed that down regulation of RAGE expression by RNAi inhibited the cell proliferation of androgen-dependent (LNCaP) and androgen-independent (DU-145) prostate cancer cells. Furthermore, targeting RAGE expression resulted in apoptotic elimination of these prostate cancer cells by activation of caspase-8 and caspase-3 death signaling. Of note, the levels of prostate specific antigen (PSA) were also reduced in LNCaP cells transfected with RAGE RNAi constructs. Importantly, the RAGE RNAi constructs when administered in nude mice bearing prostate tumors, inhibited the tumor growth by targeting the expression of RAGE, and its physiological ligand, HMGB1 and by up regulating death receptors DR4 and DR5 expression. Collectively, the results of this study for the first time show that targeting RAGE by RNAi may be a promising alternative therapeutic strategy for treating prostate cancer.

  13. Association between Advanced Glycation End Products and Impaired Fasting Glucose: Results from the SALIA Study

    PubMed Central

    Teichert, Tom; Hellwig, Anne; Peßler, Annette; Hellwig, Michael; Vossoughi, Mohammad; Sugiri, Dorothea; Vierkötter, Andrea; Schulte, Thomas; Freund, Juliane; Roden, Michael; Hoffmann, Barbara; Schikowski, Tamara; Luckhaus, Christian; Krämer, Ursula; Henle, Thomas; Herder, Christian

    2015-01-01

    Advanced glycation end products (AGEs) may contribute to the development of type 2 diabetes and related complications, whereas their role in the early deterioration of glycaemia is unknown. While previous studies used antibody-based methods to quantify AGEs, data from tandem mass spectrometry coupled liquid chromatography (LC-MS/MS)-based measurements are limited to patients with known diabetes. Here, we used the LC-MS/MS method to test the hypothesis that plasma AGE levels are higher in individuals with impaired fasting glucose (IFG) than in those with normal fasting glucose (NFG). Secondary aims were to assess correlations of plasma AGEs with quantitative markers of glucose metabolism and biomarkers of subclinical inflammation. This study included on 60 women with NFG or IFG (n = 30 each, mean age 74 years) from the German SALIA cohort. Plasma levels of free metabolites (3-deoxyfructose, 3-deoxypentosone, 3-deoxypentulose), two hydroimidazolones, oxidised adducts (carboxymethyllysine, carboxyethyllysine, methionine sulfoxide) and Nε-fructosyllysine were measured using LC-MS/MS. Plasma concentrations of all tested AGEs did not differ between the NFG and IFG groups (all p>0.05). Associations between plasma levels of AGEs and fasting glucose, insulin and HOMA-IR as a measure of insulin resistance were weak (r between -0.2 and 0.2, all p>0.05). The association between 3-deoxyglucosone-derived hydroimidazolone with several proinflammatory biomarkers disappeared upon adjustment for multiple testing. In conclusion, plasma AGEs assessed by LC-MS/MS were neither increased in IFG nor associated with parameters of glucose metabolism and subclinical inflammation in our study. Thus, these data argue against strong effects of AGEs in the early stages of deterioration of glucose metabolism. PMID:26018950

  14. A receptor-based bioadsorbent to target advanced glycation end products in chronic kidney disease

    PubMed Central

    Zhang, Yangrong; Lapidos, Karen A.; Gal-Moscovici, Anca; Sprague, Stuart M.; Ameer, Guillermo A.

    2013-01-01

    The accumulation of advanced glycation end products (AGEs) has been reported to be a major contributor to chronic systemic inflammation. AGEs are not efficiently removed by hemodialysis or the kidney of a chronic kidney disease (CKD) patient. The goal of this study was to develop a receptor for AGEs (RAGE)-based bioadsorbent device that was capable of removing endogenous AGEs from human blood. The extracellular domain of RAGE was immobilized onto agarose beads to generate the bioadsorbent. The efficacy of AGE removal from saline, serum, and whole blood; biological effects of AGE reduction; and hemocompatibility and stability of the bioadsorbent were investigated. The bioadsorbent bound AGE-modified bovine serum albumin (AGE-BSA) with a binding capacity of 0.73 ± 0.07 mg AGE-BSA/ml bioadsorbent. The bioadsorbent significantly reduced the concentration of total AGEs in serum isolated from end stage kidney disease (ESKD) patients by 57%. AGE removal resulted in a significant reduction of vascular cell adhesion molecule-1 (VCAM-1) expression in human endothelial cells and abolishment of osteoclast formation in osteoclast progenitor cells. A hollow fiber device loaded with bioadsorbent reduced endogenous AGEs from recirculated blood to 36% of baseline levels with no significant changes in total protein and albumin concentration. The bioadsorbent maintained AGE-specific binding capacity after freeze-drying and storage for 1 year. This approach provides the foundation for further development of sRAGE-based extracorporeal therapies to selectively deplete serum AGEs from human blood and decrease inflammation in patients with diabetes and/or CKD. PMID:24206165

  15. Advanced Glycation End Products and Oxidative Stress in Type 2 Diabetes Mellitus

    PubMed Central

    Nowotny, Kerstin; Jung, Tobias; Höhn, Annika; Weber, Daniela; Grune, Tilman

    2015-01-01

    Type 2 diabetes mellitus (T2DM) is a very complex and multifactorial metabolic disease characterized by insulin resistance and β cell failure leading to elevated blood glucose levels. Hyperglycemia is suggested to be the main cause of diabetic complications, which not only decrease life quality and expectancy, but are also becoming a problem regarding the financial burden for health care systems. Therefore, and to counteract the continually increasing prevalence of diabetes, understanding the pathogenesis, the main risk factors, and the underlying molecular mechanisms may establish a basis for prevention and therapy. In this regard, research was performed revealing further evidence that oxidative stress has an important role in hyperglycemia-induced tissue injury as well as in early events relevant for the development of T2DM. The formation of advanced glycation end products (AGEs), a group of modified proteins and/or lipids with damaging potential, is one contributing factor. On the one hand it has been reported that AGEs increase reactive oxygen species formation and impair antioxidant systems, on the other hand the formation of some AGEs is induced per se under oxidative conditions. Thus, AGEs contribute at least partly to chronic stress conditions in diabetes. As AGEs are not only formed endogenously, but also derive from exogenous sources, i.e., food, they have been assumed as risk factors for T2DM. However, the role of AGEs in the pathogenesis of T2DM and diabetic complications—if they are causal or simply an effect—is only partly understood. This review will highlight the involvement of AGEs in the development and progression of T2DM and their role in diabetic complications. PMID:25786107

  16. Genetic analysis of advanced glycation end products in the DHS MIND study.

    PubMed

    Adams, Jeremy N; Raffield, Laura M; Martelle, Susan E; Freedman, Barry I; Langefeld, Carl D; Carr, J Jeffrey; Cox, Amanda J; Bowden, Donald W

    2016-06-15

    Advanced glycation end-products (AGEs) are a diverse group of molecules produced by the non-enzymatic addition of glucose to proteins, lipids, and nucleic acids. AGE levels have been associated with hyperglycemia and diabetic complications, especially in animal models, but less clearly in human studies. We measured total serum AGEs using an enzyme linked immunosorbant assay (ELISA) in 506 subjects from 246 families in the Diabetes Heart Study (DHS)/DHS MIND Study (n=399 type 2 diabetes (T2D)-affected). Single nucleotide polymorphisms (SNPs) in several candidate genes, including known AGE receptors, were tested for their influence on circulating AGE levels. The genetic analysis was expanded to include an exploratory genome-wide association study (GWAS) and exome chip analysis of AGEs (≈440,000 SNPs). AGEs were found to be highly heritable (h(2)=0.628, p=8.96 × 10(-10)). While no SNPs from candidate genes were significantly associated after Bonferroni correction, rs1035798 in the gene AGER was the most significantly associated (p=0.007). Additionally, rs7198427, in MT1A, showed a nominally significant p-value (p=0.0099). No SNPs from the GWAS or exome studies were identified after correction for multiple comparisons; however, rs17054480 in the PALLD2 gene on chromosome 4 showed the strongest association (p=7.77 × 10(-7)). Five SNPs at two loci (ISCA2/NPC2 and FBXO33) had p-values of less than 2.0 × 10(-5) and three additional SNPs (rs716326 in MACROD2, and rs6795197 and rs6765857 in ZBTB38) showed a nominal association with p-values of less than 1.0 × 10(-5).These findings provide a foundation for further investigation into the genetic component of circulating AGEs. PMID:26915486

  17. Sildenafil Ameliorates Advanced Glycation End Products-Induced Mitochondrial Dysfunction in HT-22 Hippocampal Neuronal Cells

    PubMed Central

    Sung, Soon Ki; Woo, Jae Suk; Kim, Young Ha; Son, Dong Wuk; Lee, Sang Weon

    2016-01-01

    Objective Accumulation of advanced glycation end-products (AGE) and mitochondrial glycation is importantly implicated in the pathological changes of the brain associated with diabetic complications, Alzheimer disease, and aging. The present study was undertaken to determine whether sildenafil, a type 5 phosphodiesterase type (PDE-5) inhibitor, has beneficial effect on neuronal cells challenged with AGE-induced oxidative stress to preserve their mitochondrial functional integrity. Methods HT-22 hippocampal neuronal cells were exposed to AGE and changes in the mitochondrial functional parameters were determined. Pretreatment of cells with sildenafil effectively ameliorated these AGE-induced deterioration of mitochondrial functional integrity. Results AGE-treated cells lost their mitochondrial functional integrity which was estimated by their MTT reduction ability and intracellular ATP concentration. These cells exhibited stimulated generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential, induction of mitochondrial permeability transition, and release of the cytochrome C, activation of the caspase-3 accompanied by apoptosis. Western blot analyses and qRT-PCR demonstrated that sildenafil increased the expression level of the heme oxygenase-1 (HO-1). CoPP and bilirubin, an inducer of HO-1 and a metabolic product of HO-1, respectively, provided a similar protective effects. On the contrary, the HO-1 inhibitor ZnPP IX blocked the effect of sildenafil. Transfection with HO-1 siRNA significantly reduced the protective effect of sildenafil on the loss of MTT reduction ability and MPT induction in AGE-treated cells. Conclusion Taken together, our results suggested that sildenafil provides beneficial effect to protect the HT-22 hippocampal neuronal cells against AGE-induced deterioration of mitochondrial integrity, and upregulation of HO-1 is involved in the underlying mechanism. PMID:27226858

  18. Effect of advanced glycation end-products on cell proliferation and cell death.

    PubMed

    Peterszegi, G; Molinari, J; Ravelojaona, V; Robert, L

    2006-09-01

    The effect of advanced glycation end products (AGE-s) was studied on the proliferation and cell death of human skin fibroblasts in culture. Several AGE-products were prepared from proteins, a peptide and amino acids, using Glucose or Fructose, with or without Fe2+. The AGE preparations increased cell death at the 7th day, after only 72 hours of incubation. Some of these glycation products modified also proliferation. This effect of AGE-s was even maintained without these products in fresh medium for a second period of incubation up to 10 days from the start of the experiment. In order to explore the role of AGE-receptors, especially of AGE-receptor and of growth factor receptors (fibroblast and epidermal growth factors receptors), antibodies to these receptors were added to cell cultures and their effect on both cell death and proliferation were determined as for the AGE-s. These anti-receptor antibodies imitated to some extent the results obtained with AGE-s, producing increase of cell death and proliferation, followed above a certain concentration of antibodies by a decrease and a new increase or plateau. This might correspond to the internalization of the receptors followed by a re-expression on the cell membrane. The role of receptor-mediated Reactive Oxygen Species-production was also explored using scavengers: N-acetyl-cysteine (NAC), L-Carnosine, superoxide dismutase (SOD) and Catalase. Several of these scavengers decreased cell death, suggesting that Reactive Oxygen Species-production is partially involved in the observed phenomena. PMID:16919894

  19. Receptor for Advanced Glycation End Products (RAGE) Serves a Protective Role during Klebsiella pneumoniae - Induced Pneumonia

    PubMed Central

    Achouiti, Ahmed; de Vos, Alex F.; van ‘t Veer, Cornelis; Florquin, Sandrine; Tanck, Michael W.; Nawroth, Peter P.; Bierhaus, Angelika; van der Poll, Tom; van Zoelen, Marieke A. D.

    2016-01-01

    Klebsiella species is the second most commonly isolated gram-negative organism in sepsis and a frequent causative pathogen in pneumonia. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory responses. We here aimed to investigate the role of RAGE in the host response to Klebsiella (K.) pneumoniae pneumonia and intransally inoculated rage gene deficient (RAGE-/-) and normal wild-type (Wt) mice with K. pneumoniae. Klebsiella pneumonia resulted in an increased pulmonary expression of RAGE. Furthermore, the high-affinity RAGE ligand high mobility group box-1 was upregulated during K. pneumoniae pneumonia. RAGE deficiency impaired host defense as reflected by a worsened survival, increased bacterial outgrowth and dissemination in RAGE-/- mice. RAGE-/- neutrophils showed a diminished phagocytosing capacity of live K. pneumoniae in vitro. Relative to Wt mice, RAGE-/- mice demonstrated similar lung inflammation, and slightly elevated—if any—cytokine and chemokine levels and unchanged hepatocellular injury. In addition, RAGE-/- mice displayed an unaltered response to intranasally instilled Klebsiella lipopolysaccharide (LPS) with respect to pulmonary cell recruitment and local release of cytokines and chemokines. These data suggest that (endogenous) RAGE protects against K. pneumoniae pneumonia. Also, they demonstrate that RAGE contributes to an effective antibacterial defense during K. pneumoniae pneumonia, at least partly via its participation in the phagocytic properties of professional granulocytes. Additionally, our results indicate that RAGE is not essential for the induction of a local and systemic inflammatory response to either intact Klebsiella or Klebsiella LPS. PMID:26824892

  20. Detection of advanced glycation end products (AGEs) on human skin by in vivo confocal Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Martin, A. A.; Pereira, L.; Ali, S. M.; Pizzol, C. D.; Tellez, C. A.; Favero, P. P.; Santos, L.; da Silva, V. V.; Praes, C. E. O.

    2016-03-01

    The aging process involves the reduction in the production of the major components of skin tissue. During intrinsic aging and photoaging processes, in dermis of human skin, fibroblasts become senescent and have decreased activity, which produce low levels of collagen. Moreover, there is accumulation of advanced glycation end products (AGEs). AGEs have incidence in the progression of age-related diseases, principally in diabetes mellitus and in Alzheimer's diseases. AGEs causes intracellular damage and/or apoptosis leading to an increase of the free radicals, generating a crosslink with skin proteins and oxidative stress. The aim of this study is to detect AGEs markers on human skin by in vivo Confocal Raman spectroscopy. Spectra were obtained by using a Rivers Diagnostic System, 785 nm laser excitation and a CCD detector from the skin surface down to 120 μm depth. We analyzed the confocal Raman spectra of the skin dermis of 30 women volunteers divided into 3 groups: 10 volunteers with diabetes mellitus type II, 65-80 years old (DEW); 10 young healthy women, 20-33 years old (HYW); and 10 elderly healthy women, 65-80 years old (HEW). Pentosidine and glucosepane were the principally identified AGEs in the hydroxyproline and proline Raman spectral region (1000-800 cm-1), in the 1.260-1.320 cm-1 region assignable to alpha-helical amide III modes, and in the Amide I region. Pentosidine and glucosepane calculated vibrational spectra were performed through Density Functional Theory using the B3LYP functional with 3-21G basis set. Difference between the Raman spectra of diabetic elderly women and healthy young women, and between healthy elderly women and healthy young women were also obtained with the purpose of identifying AGEs Raman bands markers. AGEs peaks and collagen changes have been identified and used to quantify the glycation process in human skin.

  1. Expression of the Receptor for Advanced Glycation End Products in Oligodendrocytes in Response to Oxidative Stress

    PubMed Central

    Qin, Jingdong; Goswami, Rajendra; Dawson, Sylvia; Dawson, Glyn

    2008-01-01

    Demyelination is a common result of oxidative stress in the nervous system, and we report here that the response of oligodendrocytes to oxidative stress involves the receptor for advanced glycation end products (RAGE). RAGE has not previously been reported in neonatal rat oligodendrocytes (NRO), but, by using primers specific for rat RAGE, we were able to show expression of messenger RNA (mRNA) for RAGE in NRO, and a 55-kDa protein was detected by Western blotting with antibodies to RAGE. Neonatal rat oligodendrocytes stained strongly for RAGE, suggesting membrane localization of RAGE. Addition of low concentrations of hydrogen peroxide (100 μM) initiated 55-kDa RAGE shedding from the cell membrane and the appearance of “soluble” 45-kDa RAGE in the culture medium, followed by restoration of RAGE expression to normal levels. Increasing hydrogen peroxide concentration (>200 μM) resulted in no restoration of RAGE, and the cells underwent apoptosis and necrosis. We further confirmed the observation in a human oligodendroglioma-derived (HOG) cell line. Both the antioxidant N-acetyl-L-cysteine and the broad-spectrum metalloproteases inhibitor TAPI0 were able partially to inhibit shedding of RAGE, suggesting involvement of metalloproteases in cleavage to produce soluble RAGE. The level of 55-kDa RAGE in autopsy brain of patients undergoing neurodegeneration with accompanying inflammation [multiple sclerosis and neuronal ceroid-lipofuscinosis (Batten's disease)] was much lower than that in age-matched controls, suggesting that shedding of RAGE might occur as reactive oxygen species accumulate in brain cells and be part of the process of neurodegeneration. PMID:18438937

  2. Identification of C1q as a Binding Protein for Advanced Glycation End Products.

    PubMed

    Chikazawa, Miho; Shibata, Takahiro; Hatasa, Yukinori; Hirose, Sayumi; Otaki, Natsuki; Nakashima, Fumie; Ito, Mika; Machida, Sachiko; Maruyama, Shoichi; Uchida, Koji

    2016-01-26

    Advanced glycation end products (AGEs) make up a heterogeneous group of molecules formed from the nonenzymatic reaction of reducing sugars with the free amino groups of proteins. The abundance of AGEs in a variety of age-related diseases, including diabetic complications and atherosclerosis, and their pathophysiological effects suggest the existence of innate defense mechanisms. Here we examined the presence of serum proteins that are capable of binding glycated bovine serum albumin (AGEs-BSA), prepared upon incubation of BSA with dehydroascorbate, and identified complement component C1q subcomponent subunit A as a novel AGE-binding protein in human serum. A molecular interaction analysis showed the specific binding of C1q to the AGEs-BSA. In addition, we identified DNA-binding regions of C1q, including a collagen-like domain, as the AGE-binding site and established that the amount of positive charge on the binding site was the determining factor. C1q indeed recognized several other modified proteins, including acylated proteins, suggesting that the binding specificity of C1q might be ascribed, at least in part, to the electronegative potential of the ligand proteins. We also observed that C1q was involved in the AGEs-BSA-activated deposition of complement proteins, C3b and C4b. In addition, the AGEs-BSA mediated the proteolytic cleavage of complement protein 5 to release C5a. These findings provide the first evidence of AGEs as a new ligand recognized by C1q, stimulating the C1q-dependent classical complement pathway. PMID:26731343

  3. Biological Effects Induced by Specific Advanced Glycation End Products in the Reconstructed Skin Model of Aging.

    PubMed

    Pageon, Hervé; Zucchi, Hélène; Dai, Zhenyu; Sell, David R; Strauch, Christopher M; Monnier, Vincent M; Asselineau, Daniel

    2015-01-01

    Advanced glycation end products (AGEs) accumulate in the aging skin. To understand the biological effects of individual AGEs, skin reconstructed with collagen selectively enriched with N(ɛ)-(carboxymethyl)-lysine (CML), N(ɛ)-(carboxyethyl)-lysine (CEL), methylglyoxal hydroimidazolone (MG-H1), or pentosidine was studied. Immunohistochemistry revealed increased expression of α6 integrin at the dermal epidermal junction by CEL and CML (p<0.01). Laminin 5 was diminished by CEL and MG-H1 (p<0.05). Both CML and CEL induced a robust increase (p<0.01) in procollagen I. In the culture medium, IL-6, VEGF, and MMP1 secretion were significantly decreased (p<0.05) by MG-H1. While both CEL and CML decreased MMP3, only CEL decreased IL-6 and TIMP1, while CML stimulated TIMP1 synthesis significantly (p<0.05). mRNA expression studies using qPCR in the epidermis layer showed that CEL increased type 7 collagen (COL7A1), β1, and α6 integrin, while CML increased only COL7A1 (p<0.05). MG-H1-modified collagen had no effect. Importantly, in the dermis layer, MMP3 mRNA expression was increased by both CML and MG-H1. CML also significantly increased the mRNAs of MMP1, TIMP1, keratinocyte growth factor (KGF), IL-6, and monocyte chemoattractant protein 1 (MCP1) (p<0.05). Mixed effects were present in CEL-rich matrix. Minimally glycoxidized pentosidine-rich collagen suppressed most mRNAs of the genes studied (p<0.05) and decreased VEGF and increased MCP1 protein expression. Taken together, this model of the aging skin suggests that a combination of AGEs tends to counterbalance and thus minimizes the detrimental biological effects of individual AGEs. PMID:26309782

  4. Contribution of dietary advanced glycation end products (AGE) to circulating AGE: role of dietary fat.

    PubMed

    Davis, Kathleen E; Prasad, Chandan; Vijayagopal, Parakat; Juma, Shanil; Adams-Huet, Beverley; Imrhan, Victorine

    2015-12-14

    The purpose of this pilot study was to determine whether macronutrient content (low-fat v. high-fat diet) influences an indicator of advanced glycation end products (AGE), N(ε) carboxymethyl-lysine (CML), in the context of a 1-d, high-AGE diet. The effect of the diets on inflammatory markers was also assessed. A total of nineteen overweight and obese adults (nine men and ten women) without known disease were recruited to participate in a crossover challenge of a high-fat, high-AGE (HFHA) and low-fat, high-AGE (LFHA) diet. In each phase patients had fasting blood drawn, followed by consumption of a high-fat or low-fat breakfast test meal, then three postprandial blood draws at 1, 2 and 3 h after consuming the test meal. After consuming high-AGE meals for the remainder of the day, participants returned the next day for a follow-up analysis. A different pattern in the 3-h post-meal CML and soluble receptor for AGE response to the two diets was observed (P=0·01 and 0·05, respectively). No change in serum CML was observed following consumption of a LFHA breakfast (535 (25th-75th percentile 451-790) to 495 (25th-75th percentile 391-682) ng/ml; P=0·36), whereas a rise in CML occurred after the HFHA breakfast (463 (25th-75th percentile 428-664) to 578 (25th-75th percentile 474-865) ng/ml; P=0·05). High sensitivity C-reactive protein and high molecular weight adiponectin were not affected by either diet. These findings suggest that dietary CML may not be as important in influencing serum CML as other dietary factors. In addition, acute exposure to dietary CML may not influence inflammation in adults without diabetes or kidney disease. This is contrary to previous findings. PMID:26392152

  5. Advanced Glycation End Products Evolution after Pancreas-Kidney Transplantation: Plasmatic and Cutaneous Assessments

    PubMed Central

    Oliveira, José C.; Vizcaíno, José Ramón; Gouveia, Carlos; Silva, Donzília; Henriques, António C.; Noronha, Irene L.; Rodrigues, Anabela

    2016-01-01

    Diabetes mellitus leads to increased Advanced Glycation End Products (AGE) production, which has been associated with secondary diabetic complications. Type 1 diabetic patients undergoing pancreas-kidney transplantation (SPKT) can restore normoglycemia and renal function, eventually decreasing AGE accumulation. We aimed to prospectively study AGE evolution after SPKT. Circulating AGE were assessed in 20 patients, at time 0 (T0), 3 months (T3), 6 months (T6), and 12 months (T12) after successful SPKT. Global AGE and carboxymethyllysine (CML) were analyzed, as well as advanced oxidation protein products (AOPP). Skin biopsies were obtained at T0 and T12. Immunohistochemistry with anti-AGE antibody evaluated skin AGE deposition. AGE mean values were 16.8 ± 6.4 μg/mL at T0; 17.1 ± 3.8 μg/mL at T3; 17.5 ± 5.6 μg/mL at T6; and 16.0 ± 5.2 μg/mL at T12. CML mean values were 0.94 ± 0.36 ng/mL at T0; 1.11 ± 0.48 ng/mL at T3; 0.99 ± 0.42 ng/mL at T6; and 0.78 ± 0.38 ng/mL at T12. AOPP mean values were 130.1 ± 76.8 μMol/L at T0; 137.3 ± 110.6 μMol/L at T3; 116.4 ± 51.2 μMol/L at T6; and 106.4 ± 57.9 μMol/L at T12. CML variation was significant (P = 0.022); AOPP variation was nearly significant (P = 0.076). Skin biopsies evolved mostly from a cytoplasmic diffuse to a peripheral interkeratinocytic immunoreaction pattern; in 7 cases, a reduction in AGE immunoreaction intensity was evident at T12. In conclusion, glycoxidation markers decrease, plasmatic and on tissues, may start early after SPKT. Studies with prolonged follow-up may confirm these data. PMID:26881017

  6. Advanced Glycation End Products Acutely Impair Ca2+ Signaling in Bovine Aortic Endothelial Cells

    PubMed Central

    Naser, Nadim; Januszewski, Andrzej S.; Brown, Bronwyn E.; Jenkins, Alicia J.; Hill, Michael A.; Murphy, Timothy V.

    2013-01-01

    Post-translational modification of proteins in diabetes, including formation of advanced glycation end products (AGEs) are believed to contribute to vascular dysfunction and disease. Impaired function of the endothelium is an early indicator of vascular dysfunction in diabetes and as many endothelial cell processes are dependent upon intracellular [Ca2+] and Ca2+ signaling, the aim of this study was to examine the acute effects of AGEs on Ca2+ signaling in bovine aortic endothelial cells (BAEC). Ca2+ signaling was studied using the fluorescent indicator dye Fura-2-AM. AGEs were generated by incubating bovine serum albumin with 0–250 mM glucose or glucose-6-phosphate for 0–120 days at 37°C. Under all conditions, the main AGE species generated was carboxymethyl lysine (CML) as assayed using both gas-liquid chromatograph-mass spectroscopy and high-performance liquid chromatography. In Ca2+-replete solution, exposure of BAEC to AGEs for 5 min caused an elevation in basal [Ca2+] and attenuated the increase in intracellular [Ca2+] caused by ATP (100 μM). In the absence of extracellular Ca2+, exposure of BAEC to AGEs for 5 min caused an elevation in basal [Ca2+] and attenuated subsequent intracellular Ca2+ release caused by ATP, thapsigargin (0.1 μM), and ionomycin (3 μM), but AGEs did not affect extracellular Ca2+ entry induced by the re-addition of Ca2+ to the bathing solution in the presence of any of these agents. The anti-oxidant α-lipoic acid (2 μM) and NAD(P)H oxidase inhibitors apocynin (500 μM) and diphenyleneiodonium (1 μM) abolished these effects of AGEs on BAECs, as did the IP3 receptor antagonist xestospongin C (1 μM). In summary, AGEs caused an acute depletion of Ca2+ from the intracellular store in BAECs, such that the Ca2+ signal stimulated by the subsequent application other agents acting upon this store is reduced. The mechanism may involve generation of reactive oxygen species from NAD(P)H oxidase and possible

  7. Imaging of Receptors for Advanced Glycation End Products in Experimental Myocardial Ischemia and Reperfusion Injury

    PubMed Central

    Tekabe, Yared; Luma, Joane; Li, Qing; Schmidt, Ann Marie; Ramasamy, Ravichandran; Johnson, Lynne L.

    2013-01-01

    OBJECTIVES The aim of this study was to image expression of receptor for advanced glycation end products (RAGE) in a mouse model of myocardial reperfusion injury. BACKGROUND RAGE and its ligands are implicated in the pathogenesis of ischemia/reperfusion injury and infarction. We hypothesized that RAGE-directed quantitative imaging of myocardial uptake of technetium-99m (99mTc)-anti-RAGE F(ab′)2 in a mouse model of myocardial ischemic injury can detect RAGE expression and show quantitative differences between early (18 to 20 h) and later times (48 h) after reperfusion. METHODS Twenty-five wild-type (WT) mice underwent left anterior descending coronary artery occlusion for 30 min. Mice were injected with 19.98 ± 1.78 MBq of 99mTc anti-RAGE F(ab′)2 at 2 time points after reperfusion (at 18 to 20 h [n = 8] and at 48 h [n = 12]) and 5 h later with 6.14 ± 2.0 MBq of thallium-201 (201Tl). Five WT mice were injected with nonspecific F(ab′)2 and 201Tl 18 to 20 h after reperfusion. Six WT mice underwent sham operation without coronary intervention. After injection with 201Tl, all mice immediately underwent dual isotope single-photon emission computed tomography/computed tomography. At completion of imaging, hearts were counted and sectioned. RESULTS The uptake of 99mTc-anti-RAGE F(ab′)2 in the ischemic zone from the scans as mean percentage injected dose was significantly greater at 18 to 20 h (5.7 ± 2.1 × 10−3%) as compared with at 48 h (1.4 ± 1.1 × 10−3%; p < 0.001) after reperfusion. Disease and antibody controls showed no focal uptake in the infarct. Gamma well counting of the myocardium supported the quantitative scan data. By immunohistochemical staining there was greater caspase-3 and RAGE staining at 18 to 20 h versus at 48 h (p = 0.04 and p = 0.01, respectively). On dual immunofluorescence, RAGE colocalized mainly with injured cardiomyocytes undergoing apoptosis. CONCLUSIONS RAGE expression in myocardial ischemic injury can be imaged in vivo using

  8. An improved expression system for the VC1 ligand binding domain of the receptor for advanced glycation end products in Pichia pastoris.

    PubMed

    Degani, Genny; Colzani, Mara; Tettamanzi, Alberto; Sorrentino, Luca; Aliverti, Alessandro; Fritz, Guenter; Aldini, Giancarlo; Popolo, Laura

    2015-10-01

    The receptor for the advanced glycation end products (RAGE) is a type I transmembrane glycoprotein belonging to the immunoglobulin superfamily and binds a variety of unrelated ligands sharing a negative charge. Most ligands bind to the extracellular V or VC1 domains of the receptor. In this work, V and VC1 of human RAGE were produced in the methylotrophic yeast Pichia pastoris and directed to the secretory pathway. Fusions to a removable C-terminal His-tag evidenced proteolytic processing of the tag by extracellular proteases and also intracellular degradation of the N-terminal portion of V-His. Expression of untagged forms was attempted. While the V domain was retained intracellularly, VC1 was secreted into the medium and was functionally active in binding AGEs. The glycosylation state of VC1 was analyzed by mass spectrometry and peptide-N-glycosidase F digestion. Like RAGE isolated from mammalian sources, the degree of occupancy of the N-glycosylation sites was full at Asn25 and partial at Asn81 which was also subjected to non-enzymatic deamidation. A simple procedure for the purification to homogeneity of VC1 from the medium was developed. The folded state of the purified protein was assessed by thermal shift assays. Recombinant VC1 from P. pastoris showed a remarkably high thermal stability as compared to the protein expressed in bacteria. Our in vivo approach indicates that the V and C1 domains constitute a single folding unit. The stability and solubility of the yeast-secreted VC1 may be beneficial for future in vitro studies aimed to identify new ligands or inhibitors of RAGE. PMID:26118699

  9. Advanced glycation end products and their receptors co-localise in rat organs susceptible to diabetic microvascular injury.

    PubMed

    Soulis, T; Thallas, V; Youssef, S; Gilbert, R E; McWilliam, B G; Murray-McIntosh, R P; Cooper, M E

    1997-06-01

    Advanced glycation end products (AGEs) are believed to play an important role in the development of diabetic complications. AGEs are increased in experimental diabetes and treatment with the inhibitor of advanced glycation end products, aminoguanidine, has been shown to attenuate the level of these products in tissues undergoing complications. Recently, an AGE-binding protein has been isolated from bovine lung endothelial cells and termed the receptor for advanced glycated end products (RAGE). The present study sought to determine the distribution of AGE and RAGE in tissues susceptible to the long-term complications of diabetes including the kidney, eye, nerve, arteries as well as in a tissue resistant to such complications, the lung. Using polyclonal antisera both AGE and RAGE were found to co-localize in the renal glomerulus. AGE staining was clearly increased with age and was further increased by diabetes. Aminoguanidine treatment reduced AGE accumulation in the kidney. Co-localisation of AGE and RAGE was demonstrated in the inner plexiform layer and the inner limiting membrane of the retina and in nerve bundles from mesenteric arteries. In the aorta, both AGE and RAGE were found in the intima, media and adventitia. Medial staining was increased in diabetes and was reduced by aminoguanidine treatment. A similar pattern was observed for RAGE in the aorta. In the lung, RAGE was found widely distributed throughout the lung whereas the distribution of AGE staining was more limited, primarily localising to macrophages. The co-localisation of AGEs and RAGE in sites of diabetic microvascular injury suggests that this ligand-receptor interaction may represent an important mechanism in the genesis of diabetic complications. PMID:9222639

  10. The human and rat recombinant receptors for advanced glycation end products have a high degree of homology but different pharmacokinetic properties in rats.

    PubMed

    Renard, C; Chappey, O; Wautier, M P; Nagashima, M; Morser, J; Scherrmann, J M; Wautier, J L

    1999-09-01

    The accelerated formation of advanced glycation end products (AGEs) is implicated in diabetic microvascular and macrovascular complications. The binding of AGEs to their cellular surface receptor (RAGE) induces vascular dysfunction and in particular an increase in vascular permeability. We previously demonstrated that rat recombinant RAGE (rR-RAGE) produced in insect cells corrected the hyperpermeability due to RAGE-AGE interaction and that pharmacokinetic properties of rR-RAGE after i.v. administration in rats were compatible with a potential therapeutic use. In the present study, we showed that recombinant human RAGE (rH-RAGE) had a similar efficacy in inhibiting AGE-induced endothelial alteration and in reducing the hyperpermeability observed in streptozotocin-induced diabetic rats. (125)I-rH-RAGE elimination half-life after i.v. administration was similar in diabetic and normal rats (53.7 +/- 7.6 and 45.3 +/- 4.0 h, respectively). The presence of AGEs is responsible for a higher distribution volume in diabetic rats compared with normal rats (15.3 +/- 2.7 and 7.7 +/- 0. 7 l/kg, respectively). Immunoreactive (125)I-rH-RAGE decreased more rapidly than did immunoreactive (125)I-rR-RAGE. The differences between (125)I-rH-RAGE and (125)I-rR-RAGE pharmacokinetics in rat may be related to differences in potential O-glycosylation and protease cleavage sites between the two RAGE molecules. PMID:10454525

  11. Accumulation of Advanced Glycation End-Products and Activation of the SCAP/SREBP Lipogenetic Pathway Occur in Diet-Induced Obese Mouse Skeletal Muscle

    PubMed Central

    Mastrocola, Raffaella; Collino, Massimo; Nigro, Debora; Chiazza, Fausto; D’Antona, Giuseppe; Aragno, Manuela; Minetto, Marco A.

    2015-01-01

    Aim of this study was to investigate whether advanced glycation end-products (AGEs) accumulate in skeletal myofibers of two different animal models of diabesity and whether this accumulation could be associated to myosteatosis. Male C57Bl/6j mice and leptin-deficient ob/ob mice were divided into three groups and underwent 15 weeks of dietary manipulation: standard diet-fed C57 group (C57, n = 10), high-fat high-sugar diet-fed C57 group (HFHS, n = 10), and standard diet-fed ob/ob group (OB/OB, n = 8). HFHS mice and OB/OB mice developed glycometabolic abnormalities in association with decreased mass of the gastrocnemius muscle, fast-to-slow transition of muscle fibers, and lipid accumulation (that occurred preferentially in slow compared to fast fibers). Moreover, we found in muscle fibers of HFHS and OB/OB mice accumulation of AGEs that was preferential for the lipid-accumulating cells, increased expression of the lipogenic pathway SCAP/SREBP, and co-localisation between AGEs and SCAP-(hyper)expressing cells (suggestive for SCAP glycosylation). The increased expression of the SCAP/SREBP lipogenic pathway in muscle fibers is a possible mechanism underlying lipid accumulation and linking myosteatosis to muscle fiber atrophy and fast-to-slow transition that occur in response to diabesity. PMID:25750996

  12. Advanced glycation end products induce oxidative stress and mitochondrial dysfunction in SH-SY5Y cells.

    PubMed

    Wang, Xu; Yu, Song; Wang, Chun-Yan; Wang, Yue; Liu, Hai-Xing; Cui, Yong; Zhang, Li-De

    2015-02-01

    This study aimed to investigate the direct effects of advanced glycation end products (AGEs) on the mitochondrial structure and function of SH-SY5Y cells and the possible molecular mechanism(s) underlying mitochondria dysfunction by AGEs. SH-SY5Y cells were cultured in 400 μg/ml of AGE-bovine serum albumin (BSA) for 24 h, and changes in the mitochondrial function of SH-SY5Y cells were analysed as follows. Reactive oxygen species (ROS) were detected using 2',7'-dichlorodihydrofluorescein diacetate molecular probes. Mitochondrial membrane potential (ΔΨm) was determined by flow cytometry using fluorescent probes. The expression of cytochrome c (Cyt c) protein level was assessed by Western blotting. Mitochondrial structures were observed by transmission electron microscopy. Our results showed that AGE-BSA induced an increase in ROS levels, a decrease in mitochondrial ΔΨm, and the release of Cyt c from mitochondria in SH-SY5Y cells. The mitochondria of SH-SY5Y cells showed remarkable swelling and vacuolisation, but these changes were recovered after pretreatment with neutralising anti-receptor for advanced glycation end products (RAGE) antibody. Our results suggested that AGE-BSA induced mitochondrial dysfunction in SH-SY5Y cells through RAGE pathways. Thus, AGEs are potential mechanistic links between diabetes mellitus and Alzheimer's disease. PMID:25381033

  13. Advanced lipid peroxidation end products in oxidative damage to proteins. Potential role in diseases and therapeutic prospects for the inhibitors

    PubMed Central

    Negre-Salvayre, A; Coatrieux, C; Ingueneau, C; Salvayre, R

    2007-01-01

    Reactive carbonyl compounds (RCCs) formed during lipid peroxidation and sugar glycoxidation, namely Advanced lipid peroxidation end products (ALEs) and Advanced Glycation end products (AGEs), accumulate with ageing and oxidative stress-related diseases, such as atherosclerosis, diabetes or neurodegenerative diseases. RCCs induce the ‘carbonyl stress' characterized by the formation of adducts and cross-links on proteins, which progressively leads to impaired protein function and damages in all tissues, and pathological consequences including cell dysfunction, inflammatory response and apoptosis. The prevention of carbonyl stress involves the use of free radical scavengers and antioxidants that prevent the generation of lipid peroxidation products, but are inefficient on pre-formed RCCs. Conversely, carbonyl scavengers prevent carbonyl stress by inhibiting the formation of protein cross-links. While a large variety of AGE inhibitors has been developed, only few carbonyl scavengers have been tested on ALE-mediated effects. This review summarizes the signalling properties of ALEs and ALE-precursors, their role in the pathogenesis of oxidative stress-associated diseases, and the different agents efficient in neutralizing ALEs effects in vitro and in vivo. The generation of drugs sharing both antioxidant and carbonyl scavenger properties represents a new therapeutic challenge in the treatment of carbonyl stress-associated diseases. PMID:17643134

  14. Implication of advanced glycation end products (Ages) and their receptor (Rage) on myocardial contractile and mitochondrial functions.

    PubMed

    Neviere, Remi; Yu, Yichi; Wang, Lei; Tessier, Frederic; Boulanger, Eric

    2016-08-01

    Advanced glycation end products (AGEs) play an important role for the development and/or progression of cardiovascular diseases, mainly through induction of oxidative stress and inflammation. AGEs are a heterogeneous group of molecules formed by non-enzymatic reaction of reducing sugars with amino acids of proteins, lipids and nucleic acids. AGEs are mainly formed endogenously, while recent studies suggest that diet constitutes an important exogenous source of AGEs. The presence and accumulation of AGEs in various cardiac cell types affect extracellular and intracellular structure and function. AGEs contribute to a variety of microvascular and macrovascular complications through the formation of cross-links between molecules in the basement membrane of the extracellular matrix and by engaging the receptor for advanced glycation end products (RAGE). Activation of RAGE by AGEs causes up regulation of the transcription factor nuclear factor-κB and its target genes. of the RAGE engagement stimulates oxidative stress, evokes inflammatory and fibrotic reactions, which all contribute to the development and progression of devastating cardiovascular disorders. This review discusses potential targets of glycation in cardiac cells, and underlying mechanisms that lead to heart failure with special interest on AGE-induced mitochondrial dysfunction in the myocardium. PMID:27277623

  15. Hyperoside Downregulates the Receptor for Advanced Glycation End Products (RAGE) and Promotes Proliferation in ECV304 Cells via the c-Jun N-Terminal Kinases (JNK) Pathway Following Stimulation by Advanced Glycation End-Products In Vitro

    PubMed Central

    Zhang, Zhengyu; Sethiel, Mosha Silas; Shen, Weizhi; Liao, Sentai; Zou, Yuxiao

    2013-01-01

    Hyperoside is a major active constituent in many medicinal plants which are traditionally used in Chinese medicines for their neuroprotective, anti-inflammatory and antioxidative effects. The molecular mechanisms underlying these effects are unknown. In this study, quiescent ECV304 cells were treated in vitro with advanced glycation end products (AGEs) in the presence or absence of hyperoside. The results demonstrated that AGEs induced c-Jun N-terminal kinases (JNK) activation and apoptosis in ECV304 cells. Hyperoside inhibited these effects and promoted ECV304 cell proliferation. Furthermore, hyperoside significantly inhibited RAGE expression in AGE-stimulated ECV304 cells, whereas knockdown of RAGE inhibited AGE-induced JNK activation. These results suggested that AGEs may promote JNK activation, leading to viability inhibition of ECV304 cells via the RAGE signaling pathway. These effects could be inhibited by hyperoside. Our findings suggest a novel role for hyperoside in the treatment and prevention of diabetes. PMID:24252909

  16. Age-related accumulation of advanced glycation end-products-albumin, S100β, and the expressions of advanced glycation end product receptor differ in visceral and subcutaneous fat.

    PubMed

    Son, Kuk Hui; Son, Myeongjoo; Ahn, Hyosang; Oh, Seyeon; Yum, Yoonji; Choi, Chang Hu; Park, Kook Yang; Byun, Kyunghee

    2016-08-19

    Visceral fat induces more inflammation by activating macrophages than subcutaneous fat, and inflammation is an underlying feature of the pathogeneses of various diseases, including cardiovascular disease and diabetes. Advanced glycation end products (AGEs), S100β, and their receptors, the receptor for advanced glycation end products (RAGE), lead to macrophage activation. However, little information is available regarding the differential accumulations of AGE-albumin (serum albumin modified by AGEs), S100β, or expressions of RAGE in different adipocyte types in fat tissues. In this study, the authors investigated whether age-related AGE-albumin accumulations S100β level, and RAGE expressions differ in subcutaneous and visceral fat tissues. Subcutaneous and visceral fat were harvested from 3- and 28-week-old rats. Macrophage activation was confirmed by Iba1 staining, and AGE-albumin accumulations and RAGE expressions were assessed by confocal microscopy. S100β were analyzed by immunoblotting. It was found that activated macrophage infiltration, AGE-albumin accumulation, and S100β in visceral fat was significantly greater in 28-week-old rats than in 3-week-old rats, but similar in subcutaneous fat. The expression of RAGE in visceral fat was much greater in 28-week-old rats, but its expression in subcutaneous fat was similar in 3- and 28-week-old rats. Furthermore, inflammatory signal pathways (NFκB, TNF-α) and proliferation pathways (FAK) in visceral fat were more activated in 28-week-old rats. These results imply that age-related AGE-albumin accumulation, S100β, and RAGE expression are more prominent in visceral than in subcutaneous fat, suggesting that visceral fat is involved in the pathogenesis of inflammation-induced diseases in the elderly. PMID:27301641

  17. Current perspectives on the health risks associated with the consumption of advanced glycation end products: recommendations for dietary management

    PubMed Central

    Palimeri, Sotiria; Palioura, Eleni; Diamanti-Kandarakis, Evanthia

    2015-01-01

    Advanced glycation end products (AGEs) constitute a complex group of compounds produced endogenously during the aging process and under conditions of hyperglycemia and oxidative stress. AGEs also have an emerging exogenous origin. Cigarette smoke and diet are the two main exogenous sources of AGEs (glycotoxins). Modern Western diets are rich in AGEs which have been implicated in the pathogenesis of several metabolic and degenerative disorders. Accumulating evidence underlies the beneficial effect of the dietary restriction of AGEs not only in animal studies but also in patients with diabetic complications and metabolic diseases. This article reviews the evidence linking dietary glycotoxins to several disorders from diabetic complications and renal failure to liver dysfunction, female reproduction, eye and cognitive disorders as well as cancer. Furthermore, strategies for AGE reduction are discussed with a focus on dietary modification. PMID:26366100

  18. Glycation of H1 Histone by 3-Deoxyglucosone: Effects on Protein Structure and Generation of Different Advanced Glycation End Products

    PubMed Central

    Ashraf, Jalaluddin Mohammad; Rabbani, Gulam; Ahmad, Saheem; Hasan, Qambar; Khan, Rizwan Hasan; Alam, Khursheed; Choi, Inho

    2015-01-01

    Advanced glycation end products (AGEs) culminate from the non-enzymatic reaction between a free carbonyl group of a reducing sugar and free amino group of proteins. 3-deoxyglucosone (3-DG) is one of the dicarbonyl species that rapidly forms several protein-AGE complexes that are believed to be involved in the pathogenesis of several diseases, particularly diabetic complications. In this study, the generation of AGEs (Nε-carboxymethyl lysine and pentosidine) by 3-DG in H1 histone protein was characterized by evaluating extent of side chain modification (lysine and arginine) and formation of Amadori products as well as carbonyl contents using several physicochemical techniques. Results strongly suggested that 3-DG is a potent glycating agent that forms various intermediates and AGEs during glycation reactions and affects the secondary structure of the H1 protein. Structural changes and AGE formation may influence the function of H1 histone and compromise chromatin structures in cases of secondary diabetic complications. PMID:26121680

  19. Inhibition of NA(+)/H(+) Exchanger 1 Attenuates Renal Dysfunction Induced by Advanced Glycation End Products in Rats.

    PubMed

    Li, Peng; Chen, Geng-Rong; Wang, Fu; Xu, Ping; Liu, Li-Ying; Yin, Ya-Ling; Wang, Shuang-Xi

    2016-01-01

    It has been recognized that sodium hydrogen exchanger 1 (NHE1) is involved in the development of diabetic nephropathy. The role of NHE1 in kidney dysfunction induced by advanced glycation end products (AGEs) remains unknown. Renal damage was induced by AGEs via tail vein injections in rats. Function and morphology of kidney were determined. Compared to vehicle- or BSA-treated rats, AGEs caused abnormalities of kidney structures and functions in rats, accompanied with higher MDA level and lower GSH content. Gene expressions of NHE1 gene and TGF-β1 in the renal cortex and urine were also increased in AGEs-injected rats. Importantly, all these detrimental effects induced by AGEs were reversed by inhibition of NHE1 or suppression of oxidative stress. These pieces of data demonstrated that AGEs may activate NHE1 to induce renal damage, which is related to TGF-β1. PMID:26697498

  20. Chemo-enzymatic synthesis of vinyl and l-ascorbyl phenolates and their inhibitory effects on advanced glycation end products.

    PubMed

    Hwang, Seung Hwan; Wang, Zhiqiang; Lim, Soon Sung

    2017-01-01

    This study successfully established the feasibility of a two-step chemo-enzymatic synthesis of l-ascorbyl phenolates. Intermediate vinyl phenolates were first chemically produced and then underwent trans-esterification with l-ascorbic acid in the presence of Novozyme 435® (Candida Antarctica lipase B) as a catalyst. Twenty vinyl phenolates and 11 ascorbyl phenolates were subjected to in vitro bioassays to investigate their inhibitory activity against advanced glycation end products (AGEs). Among them, vinyl 4-hydroxycinnamate (17VP), vinyl 4-hydroxy-3-methoxycinnamate (18VP), vinyl 4-hydroxy-3,5-dimethoxycinnamate (20VP), ascorbyl 4-hydroxy-3-methoxycinnamate (18AP) and ascorbyl 3,4-dimethoxycinnamate (19AP) showed 2-10 times stronger inhibitory activities than positive control (aminoguanidine and its precursors). These results indicated that chemo-enzymatically synthesized compounds have AGE inhibitory effect and thus are effective in either preventing or retarding glycation protein formation. PMID:27507531

  1. The renin-angiotensin system and advanced glycation end-products in diabetic retinopathy: impacts and synergies.

    PubMed

    Miller, Antonia G; Zhu, Tong; Wilkinson-Berka, Jennifer L

    2013-11-01

    Diabetic retinopathy is a major cause of vision impairment and blindness and represents a significant health burden throughout the world. There is considerable interest in developing new treatments that retard the progression of diabetic retinopathy from its early to proliferative stages. It could be argued that the absence of an ideal therapy for diabetic retinopathy comes from an incomplete understanding about the biochemical mechanisms that underlie this disease, and their precise impact on specific retinal cell populations. Findings from pre-clinical and clinical studies indicate that both the renin-angiotensin system (RAS) and advanced glycation end-products (AGEs) influence various aspects of diabetic retinopathy. Of interest is growing evidence of cross-talk between the RAS and AGEs pathways. This review will discuss the role of both the RAS and AGEs in diabetic retinopathy, and how the identification of interactions between the two pathways may have implications for the development of new treatment strategies. PMID:23173957

  2. A portable system for noninvasive assessment of advanced glycation end-products using skin fluorescence and reflectance spectrum

    NASA Astrophysics Data System (ADS)

    Wang, Y. K.; Zhu, L.; Zhang, L.; Zhang, G.; Liu, Y.; Wang, A.

    2012-07-01

    An optical system has been developed for noninvasive assessment of skin advanced glycation end-products (AGEs). The system comprises mainly a high-power ultraviolet light emitting diode (LED) as an excitation source, an LED array for the reflectance measurement, a trifurcated fiber-optic probe for light transmitting and receiving, and a compact spectrometer for light detecting. Both skin fluorescence of a subject and the reflectance spectrum of the same site can be obtained in a single measurement with the system. Demonstrative measurements with the system have been conducted. Results indicate that the measured reflectance spectrum can be used to compensate for the distortion of AGEs fluorescence, which is caused by skin absorption and scattering. The system is noninvasive, portable, easy to operate, and has potential applications for clinical diagnosis of AGE-related diseases, especially diabetes mellitus.

  3. The Role of PPARγ in Advanced Glycation End Products-Induced Inflammatory Response in Human Chondrocytes

    PubMed Central

    Li, Yu-qing; Chen, Cheng; Cai, Wei; Zeng, Yue-lin

    2015-01-01

    Objective Advances made in the past ten years highlight the notion that peroxisome proliferator-activated receptors gamma (PPARγ) has protective properties in the pathophysiology of osteoarthritis (OA). The aim of this study was to define the roles of PPARγ in AGEs-induced inflammatory response in human chondrocytes. Methods Primary human chondrocytes were stimulated with AGEs in the presence or absence of neutralizing antibody against RAGE (anti-RAGE), MAPK specific inhibitors and PPARγ agonist pioglitazone. The expression of IL-1, MMP-13, TNF-α, PPARγ, nuclear NF-κB p65 and cytosol IκBα was determined by western blotting and real-time PCR. Results AGEs could enhance the expression of IL-1, TNF-α, and MMP-13, but the level of PPARγ was decreased in a time- and dose-dependent manner, which was inhibited by anti-RAGE, SB203580 (P38 MAPK specific inhibitor) and SP600125 (a selective inhibitor of JNK). PPARγ agonist pioglitazone could inhibit the effects of AGEs-induced inflammatory response and PPARγ down-regulation. In human chondrocytes, AGEs could induce cytosol IκBα degradation and increase the level of nuclear NF-κB p65, which was inhibited by PPARγ agonist pioglitazone. Conclusions In primary human chondrocytes, AGEs could down-regulate PPARγ expression and increase the inflammatory mediators, which could be reversed by PPARγ agonist pioglitazone. Activation of RAGE by AGEs triggers a cascade of downstream signaling, including MAPK JNK/ p38, PPARγ and NF-κB. Taken together, PPARγ could be a potential target for pharmacologic intervention in the treatment of OA. PMID:26024533

  4. Imaging receptor for advanced glycation end product expression in mouse model of hind limb ischemia

    PubMed Central

    2013-01-01

    Background The purpose of this study is to image the effect of diabetes on expression of receptor for advanced glycation endproducts (RAGE) in limb ischemia in live animals. Methods Male wild-type C57BL/6 mice were either made diabetic or left as control. Two months later, diabetic and non-diabetic mice underwent left femoral artery ligation. The right leg served as lesion control. Five days later, mice were injected with 15.1 ± 4.4 MBq 99mTc-anti-RAGE F(ab’)2 and 4 to 5 h later (blood pool clearance) underwent SPECT/CT imaging. At the completion of imaging, mice were euthanized, hind limbs counted and sectioned, and scans reconstructed. Regions of interest were drawn on serial transverse sections comprising the hind limbs and activity in millicuries summed and divided by the injected dose (ID). Quantitative histology was performed for RAGE staining and angiogenesis. Results Uptake of 99mTc-anti-RAGE F(ab')2 as %ID × 10−3 was higher in the left (ischemic) limbs for the diabetic mice (n = 8) compared to non-diabetic mice (n = 8) (1.20 ± 0.44% vs. 0.49 ± 0.40%; P = 0.0007) and corresponded to less angiogenesis in the diabetic mice. Uptake was also higher in the right limbs of diabetic compared to non-diabetic animals (0.82 ± 0.33% vs. 0.40 ± 0.14%; P = 0.0004). Conclusions These data show the feasibility of imaging and quantifying the effect of diabetes on RAGE expression in limb ischemia. PMID:23663412

  5. Receptor for Advanced Glycation End-Products Signaling Interferes with the Vascular Smooth Muscle Cell Contractile Phenotype and Function.

    PubMed

    Simard, Elie; Söllradl, Thomas; Maltais, Jean-Sébastien; Boucher, Julie; D'Orléans-Juste, Pédro; Grandbois, Michel

    2015-01-01

    Increased blood glucose concentrations promote reactions between glucose and proteins to form advanced glycation end-products (AGE). Circulating AGE in the blood plasma can activate the receptor for advanced end-products (RAGE), which is present on both endothelial and vascular smooth muscle cells (VSMC). RAGE exhibits a complex signaling that involves small G-proteins and mitogen activated protein kinases (MAPK), which lead to increased nuclear factor kappa B (NF-κB) activity. While RAGE signaling has been previously addressed in endothelial cells, little is known regarding its impact on the function of VSMC. Therefore, we hypothesized that RAGE signaling leads to alterations in the mechanical and functional properties of VSMC, which could contribute to complications associated with diabetes. We demonstrated that RAGE is expressed and functional in the A7r5 VSMC model, and its activation by AGE significantly increased NF-κB activity, which is known to interfere with the contractile phenotype of VSMC. The protein levels of the contraction-related transcription factor myocardin were also decreased by RAGE activation with a concomitant decrease in the mRNA and protein levels of transgelin (SM-22α), a regulator of VSMC contraction. Interestingly, we demonstrated that RAGE activation increased the overall cell rigidity, an effect that can be related to an increase in myosin activity. Finally, although RAGE stimulation amplified calcium signaling and slightly myosin activity in VSMC challenged with vasopressin, their contractile capacity was negatively affected. Overall, RAGE activation in VSMC could represent a keystone in the development of vascular diseases associated with diabetes by interfering with the contractile phenotype of VSMC through the modification of their mechanical and functional properties. PMID:26248341

  6. A cross talk between class A scavenger receptor and receptor for advanced glycation end-products contributes to diabetic retinopathy.

    PubMed

    Ma, Ke; Xu, Yiming; Wang, Chenchen; Li, Nan; Li, Kexue; Zhang, Yan; Li, Xiaoyu; Yang, Qing; Zhang, Hanwen; Zhu, Xudong; Bai, Hui; Ben, Jingjing; Ding, Qingqing; Li, Keran; Jiang, Qin; Xu, Yong; Chen, Qi

    2014-12-15

    In response to hyperglycemia in patients with diabetes, many signaling pathways contribute to the pathogenesis of diabetic complications, including diabetic retinopathy (DR). Excessive production of inflammatory mediators plays an important role in this process. Amadori-glycated albumin, one of the major forms of advanced glycated end-products, has been implicated in DR by inducing inflammatory responses in microglia/macrophages. Our goal was to delineate the potential cross talk between class A scavenger receptor (SR-A) and the receptor for advanced glycated end-product (RAGE) in the context of DR. We show here that SR-A ablation caused an exacerbated form of DR in streptozotocin-injected C57BL/6J mice as evidenced by fundus imaging and electroretinography. Immunohistochemical staining and RT-PCR assay indicated that there was augmented activation of proinflammatory macrophages with upregulated synthesis of proinflammatory mediators in the retina in Sr-a(-/-) mice. Overexpression of SR-A suppressed RAGE-induced mitogen-activated protein kinase (MAPK) signaling, whereas RAGE activation in macrophages favored a proinflammatory (M1) phenotype in the absence of SR-A. Mechanistic analysis on bone marrow-derived macrophages and HEK293 cell line revealed that SR-A interacted with and inhibited the phosphorylation of mitogen-activated protein kinase kinase 7, the major kinase in the RAGE-MAPK-NF-κB signaling, thereby leading to diminished secretion of proinflammatory cytokines. Our findings suggest that the antagonism between SR-A and RAGE contributes to the pathogenesis of DR by nurturing a disease-prone macrophage phenotype. Therefore, specific agonist that boosts SR-A signaling could potentially provide benefits in the prevention and/or intervention of DR. PMID:25352436

  7. Receptor for Advanced Glycation End-Products Signaling Interferes with the Vascular Smooth Muscle Cell Contractile Phenotype and Function

    PubMed Central

    Simard, Elie; Söllradl, Thomas; Maltais, Jean-Sébastien; Boucher, Julie; D’Orléans-Juste, Pédro; Grandbois, Michel

    2015-01-01

    Increased blood glucose concentrations promote reactions between glucose and proteins to form advanced glycation end-products (AGE). Circulating AGE in the blood plasma can activate the receptor for advanced end-products (RAGE), which is present on both endothelial and vascular smooth muscle cells (VSMC). RAGE exhibits a complex signaling that involves small G-proteins and mitogen activated protein kinases (MAPK), which lead to increased nuclear factor kappa B (NF-κB) activity. While RAGE signaling has been previously addressed in endothelial cells, little is known regarding its impact on the function of VSMC. Therefore, we hypothesized that RAGE signaling leads to alterations in the mechanical and functional properties of VSMC, which could contribute to complications associated with diabetes. We demonstrated that RAGE is expressed and functional in the A7r5 VSMC model, and its activation by AGE significantly increased NF-κB activity, which is known to interfere with the contractile phenotype of VSMC. The protein levels of the contraction-related transcription factor myocardin were also decreased by RAGE activation with a concomitant decrease in the mRNA and protein levels of transgelin (SM-22α), a regulator of VSMC contraction. Interestingly, we demonstrated that RAGE activation increased the overall cell rigidity, an effect that can be related to an increase in myosin activity. Finally, although RAGE stimulation amplified calcium signaling and slightly myosin activity in VSMC challenged with vasopressin, their contractile capacity was negatively affected. Overall, RAGE activation in VSMC could represent a keystone in the development of vascular diseases associated with diabetes by interfering with the contractile phenotype of VSMC through the modification of their mechanical and functional properties. PMID:26248341

  8. Increased concentration of two different advanced glycation end-products detected by enzyme immunoassays with new monoclonal antibodies in sera of patients with rheumatoid arthritis

    PubMed Central

    2010-01-01

    Background Levels of pentosidine (representative of advanced glycation end-products) in sera of patients with rheumatoid arthritis are increased when compared with sera of other diagnoses or healthy controls. These levels have been reported to correlate with clinical indices of rheumatoid arthritis activity and with laboratory markers of inflammation. The purpose of this study was to find out if these findings pertain to other advanced glycation end-products. Methods We have developed two immunoassays based on new monoclonal antibodies to advanced glycation end-products. Antibody 103-E3 reacts with an unidentified antigen, formed in the reaction of proteins with ribose, while antibody 8-C1 responds to Nε-(carboxyethyl)lysine. We have used these monoclonal antibodies to measure levels of advanced glycation end-products in sera of patients with rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis, and healthy controls. We calculated the correlations between advanced glycation end-product levels in rheumatoid arthritis sera and the Disease Activity Score 28 (DAS28), age, disease duration, CRP, anti-CCP, rheumatoid factor and treatment with corticosteroids, respectively. Results Levels of both glycation products were significantly higher in sera of patients with rheumatoid arthritis when compared with sera of patients with systemic lupus erythematosus, osteoarthritis, or the healthy controls. Neither the level of Nε-(carboxyethyl)lysine nor the level of the 103-E3 antigen in rheumatoid arthritis sera correlated with the DAS28-scored rheumatoid arthritis activity. The levels of both antigens in rheumatoid arthritis sera did not correlate with age, gender, corticosteroid treatment, or levels of CRP, anti-CCP antibodies, and rheumatoid factor in sera. Conclusions We report highly specific increases in the levels of two advanced glycation end-products in sera of patients with rheumatoid arthritis. This increase could be explained neither by rheumatoid

  9. Diabetic kidney disease: a role for advanced glycation end-product receptor 1 (AGE-R1)?

    PubMed

    Zhuang, Aowen; Forbes, Josephine M

    2016-08-01

    Diabetic patients are postulated to be in a perpetual state of oxidative stress and inflammation at sites where chronic complications occur. The accumulation of AGEs derived from both endogenous and exogenous sources (such as the diet) have been implicated in the development and progression of diabetic complications, particularly nephropathy. There has been some interest in investigating the potential for reducing the AGE burden in chronic disease, through the action of AGE "clearance" receptors, such as the advanced glycation end-product receptor 1 (AGE-R1). Reducing the burden of AGEs has been linked to attenuation of inflammation, slower progression of diabetic complications (in particular vascular and renal complications) and has been shown to extend lifespan. To date, however, there have been no direct investigations into whether AGE-R1 has any role in modulating normal kidney function, or specifically during the development and progression of diabetes. This mini-review will focus on the recent advances in knowledge around the mechanistic function of AGE-R1 and the implications of this for the pathogenesis of diabetic kidney disease. PMID:27270766

  10. Regulation of striatal astrocytic receptor for advanced glycation end-products variants in an early stage of experimental Parkinson's disease.

    PubMed

    Viana, Sofia D; Valero, Jorge; Rodrigues-Santos, Paulo; Couceiro, Patrícia; Silva, Andréa M; Carvalho, Félix; Ali, Syed F; Fontes-Ribeiro, Carlos A; Pereira, Frederico C

    2016-08-01

    Convincing evidence indicates that advanced glycation end-products and danger-associated protein S100B play a role in Parkinson's disease (PD). These agents operate through the receptor for advanced glycation end-products (RAGE), which displays distinct isoforms playing protective/deleterious effects. However, the nature of RAGE variants has been overlooked in PD studies. Hence, we attempted to characterize RAGE regulation in early stages of PD striatal pathology. A neurotoxin-based rodent model of PD was used in this study, through administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to C57BL/6 mice. Animals were killed 6 h post-MPTP to assess S100B/RAGE contents (RT-qPCR, ELISA) and RAGE isoform density (WB) and cellular distribution (immunohistochemistry). Dopaminergic and gliotic status were also mapped (HPLC-ED, WB, immunohistochemistry). At this preliminary stage of MPTP-induced PD in mice, RAGE inhibitory isoforms were increased whereas full-length RAGE was not affected. This putative cytoprotective RAGE phenotype paired an inflammatory and pro-oxidant setting fueling DAergic denervation. Increased RAGE inhibitory variants occur in astrocytes showing higher S100B density but no overt signs of hypertrophy or NF-κB activation, a canonical effector of RAGE. These findings expand our understanding of the toxic effect of MPTP on striatum and offer first in vivo evidence of RAGE being a responder in early stages of astrogliosis dynamics, supporting a protective rather tissue-destructive phenotype of RAGE in the initial phase of PD degeneration. These data lay the groundwork for future studies on the relevance of astrocytic RAGE in DAergic neuroprotection strategies. We report increased antagonistic RAGE variants paralleling S100B up-regulation in early stages of MPTP-induced astrogliosis dynamics . We propose that selective RAGE regulation reflects a self-protective mechanism to maintain low levels of RAGE ligands , preventing long

  11. Cardiomyocyte mitochondrial respiration is reduced by receptor for advanced glycation end-product signaling in a ceramide-dependent manner.

    PubMed

    Nelson, Michael B; Swensen, Adam C; Winden, Duane R; Bodine, Jared S; Bikman, Benjamin T; Reynolds, Paul R

    2015-07-01

    Cigarette smoke exposure is associated with an increased risk of cardiovascular complications. The role of advanced glycation end products (AGEs) is already well established in numerous comorbidities, including cardiomyopathy. Given the role of AGEs and their receptor, RAGE, in activating inflammatory pathways, we sought to determine whether ceramides could be a mediator of RAGE-induced altered heart mitochondrial function. Using an in vitro model, we treated H9C2 cardiomyocytes with the AGE carboxy-methyllysine before mitochondrial respiration assessment. We discovered that mitochondrial respiration was significantly impaired in AGE-treated cells, but not when cotreated with myriocin, an inhibitor of de novo ceramide biosynthesis. Moreover, we exposed wild-type and RAGE knockout mice to secondhand cigarette smoke and found reduced mitochondrial respiration in the left ventricular myocardium from wild-type mice, but RAGE knockout mice were protected from this effect. Finally, conditional overexpression of RAGE in the lungs of transgenic mice elicited a robust increase in left ventricular ceramides in the absence of smoke exposure. Taken together, these findings suggest a RAGE-ceramide axis as an important contributor to AGE-mediated disrupted cardiomyocyte mitochondrial function. PMID:25957215

  12. Genotoxicity of Advanced Glycation End Products: Involvement of Oxidative Stress and of Angiotensin II Type 1 Receptors

    NASA Astrophysics Data System (ADS)

    Schupp, Nicole; Schinzel, Reinhard; Heidland, August; Stopper, Helga

    2005-06-01

    In patients with chronic renal failure, cancer incidence is increased. This may be related to an elevated level of genomic damage, which has been demonstrated by micronuclei formation as well as by comet assay analysis. Advanced glycation end products (AGEs) are markedly elevated in renal failure. In the comet assay, the model AGEs methylglyoxal- and carboxy(methyl)lysine-modified bovine serum albumin (BSA) induced significant DNA damage in colon, kidney, and liver cells. The addition of antioxidants prevented AGE-induced DNA damage, suggesting enhanced formation of reactive oxygen species (ROS). The coincubation with dimethylfumarate (DMF), an inhibitor of NF-κB translocation, reduced the genotoxic effect, thereby underscoring the key role of NF-κB in this process. One of the genes induced by NF-κB is angiotensinogen. The ensuing proteolytic activity yields angiotensin II, which evokes oxidative stress as well as proinflammatory responses. A modulator of the renin-angiotensin system (RAS), the angiotensin II (Ang II) receptor 1 antagonist, candesartan, yielded a reduction of the AGE-induced DNA damage, connecting the two signal pathways, RAS and AGE signaling. We were able to identify important participants in AGE-induced DNA damage: ROS, NF-κB, and Ang II, as well as modulators to prevent this DNA damage: antioxidants, DMF, and AT1 antagonists.

  13. Comprehensive analyses of how tubule occlusion and advanced glycation end-products diminish strength of aged dentin

    PubMed Central

    Shinno, Yuko; Ishimoto, Takuya; Saito, Mitsuru; Uemura, Reo; Arino, Masumi; Marumo, Keishi; Nakano, Takayoshi; Hayashi, Mikako

    2016-01-01

    In clinical dentistry, since fracture is a major cause of tooth loss, better understanding of mechanical properties of teeth structures is important. Dentin, the major hard tissue of teeth, has similar composition to bone. In this study, we investigated the mechanical properties of human dentin not only in terms of mineral density but also using structural and quality parameters as recently accepted in evaluating bone strength. Aged crown and root dentin (age ≥ 40) exhibited significantly lower flexural strength and toughness than young dentin (age < 40). Aged dentin, in which the dentinal tubules were occluded with calcified material, recorded the highest mineral density; but showed significantly lower flexural strength than young dentin. Dentin with strong alignment of the c-axis in hydroxyapatite exhibited high fracture strength, possibly because the aligned apatite along the collagen fibrils may reinforce the intertubular dentin. Aged dentin, showing a high advanced glycation end-products (AGEs) level in its collagen, recorded low flexural strength. We first comprehensively identified significant factors, which affected the inferior mechanical properties of aged dentin. The low mechanical strength of aged dentin is caused by the high mineral density resulting from occlusion of dentinal tubules and accumulation of AGEs in dentin collagen. PMID:26797297

  14. Advanced glycation end products are mitogenic signals and trigger cell cycle reentry of neurons in Alzheimer's disease brain.

    PubMed

    Kuhla, Angela; Ludwig, Sophie C; Kuhla, Björn; Münch, Gerald; Vollmar, Brigitte

    2015-02-01

    Neurons that reenter the cell cycle die rather than divide, a phenomenon that is associated with neurodegeneration in Alzheimer's disease (AD). Reexpression of cell-cycle related genes in differentiated neurons in AD might be rooted in aberrant mitogenic signaling. Because microglia and astroglia proliferate in the vicinity of amyloid plaques, it is likely that plaque components or factors secreted from plaque-activated glia induce neuronal mitogenic signaling. Advanced glycation end products (AGEs), protein-bound oxidation products of sugar, might be one of those mitogenic compounds. Cyclin D1 positive neurons are colocalized with AGEs or directly surrounded by extracellular AGE deposits in AD brain. However, a direct proof of DNA replication in these cells has been missing. Here, we report by using fluorescent in situ hybridization that consistent with the expression of cell cycle proteins, hyperploid neuronal cells are in colocalization with AGE staining in AD brains but not in nondemented controls. To complement human data, we used apolipoprotein E-deficient mice as model of neurodegeneration and showed that increased oxidative stress caused an intensified neuronal deposition of AGEs, being accompanied by an activation of the MAPK cascade via RAGE. This cascade, in turn, induced the expression of cyclin D1 and DNA replication. In addition, reduction of oxidative stress by application of α-lipoic acid decreased AGE accumulations, and this decrease was accompanied by a reduction in cell cycle reentry and a more euploid neuronal genome. PMID:25448604

  15. Glycative stress from advanced glycation end products (AGEs) and dicarbonyls: An emerging biological factor in cancer onset and progression.

    PubMed

    Lin, Jer-An; Wu, Chi-Hao; Lu, Chi-Cheng; Hsia, Shih-Min; Yen, Gow-Chin

    2016-08-01

    In recent years, glycative stress from exogenous or endogenous advanced glycation end products (AGEs) and highly reactive dicarbonyls has gained great attention for its putative effects on cancer development. AGEs are a group of compounds formed from the complex chemical reaction of reducing sugars with compounds containing an amino group. AGEs bind to and activate the receptor for AGEs (RAGE), which is a predominant modulator of inflammation-associated cancer, and AGEs induce reactive oxygen species that are an important regulator of the hallmarks of cancer. Dicarbonyls, which are formed during glycolysis, lipid oxidation, or protein degradation, include glyoxal, methylglyoxal, and 3-deoxyglucosone and are regarded as major precursors of AGEs. These dicarbonyls not only fuel the AGE pool in living organisms but also evoke carbonyl stress, which may contribute to the carbonylative damage of carbohydrates, lipids, proteins, or DNA. Carbonylative damage then leads to many lesions, some of which are implicated in the pathogenesis of cancer. In this review, studies regarding the effects of AGEs and dicarbonyls on cancer onset or progression are systematically discussed, and the utilization of AGE inhibitors and dicarbonyl scavengers in cancer therapy are noted. PMID:26774083

  16. Overexpression of Receptor for Advanced Glycation End Products and High-Mobility Group Box 1 in Human Dental Pulp Inflammation

    PubMed Central

    Tancharoen, Salunya; Tengrungsun, Tassanee; Suddhasthira, Theeralaksna; Kikuchi, Kiyoshi; Vechvongvan, Nuttavun; Maruyama, Ikuro

    2014-01-01

    High mobility group box 1 (HMGB1), a nonhistone DNA-binding protein, is released into the extracellular space and promotes inflammation. HMGB1 binds to related cell signaling transduction receptors, including receptor for advanced glycation end products (RAGE), which actively participate in vascular and inflammatory diseases. The aim of this study was to examine whether RAGE and HMGB1 are involved in the pathogenesis of pulpitis and investigate the effect of Prevotella intermedia (P. intermedia) lipopolysaccharide (LPS) on RAGE and HMGB1 expression in odontoblast-like cells (OLC-1). RAGE and HMGB1 expression levels in clinically inflamed dental pulp were higher than those in healthy dental pulp. Upregulated expression of RAGE was observed in odontoblasts, stromal pulp fibroblasts-like cells, and endothelial-like cell lining human pulpitis tissue. Strong cytoplasmic HMGB1 immunoreactivity was noted in odontoblasts, whereas nuclear HMGB1 immunoreactivity was seen in stromal pulp fibroblasts-like cells in human pulpitis tissue. LPS stimulated OLC-1 cells produced HMGB1 in a dose-dependent manner through RAGE. HMGB1 translocation towards the cytoplasm and secretion from OLC-1 in response to LPS was inhibited by TPCA-1, an inhibitor of NF-κB activation. These findings suggest that RAGE and HMGB1 play an important role in the pulpal immune response to oral bacterial infection. PMID:25114379

  17. Modeling the Interaction between Quinolinate and the Receptor for Advanced Glycation End Products (RAGE): Relevance for Early Neuropathological Processes

    PubMed Central

    Serratos, Iris N.; Castellanos, Pilar; Pastor, Nina; Millán-Pacheco, César; Rembao, Daniel; Pérez-Montfort, Ruy; Cabrera, Nallely; Reyes-Espinosa, Francisco; Díaz-Garrido, Paulina; López-Macay, Ambar; Martínez-Flores, Karina; López-Reyes, Alberto; Sánchez-García, Aurora; Cuevas, Elvis; Santamaria, Abel

    2015-01-01

    The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor involved in neurodegenerative and inflammatory disorders. RAGE induces cellular signaling upon binding to a variety of ligands. Evidence suggests that RAGE up-regulation is involved in quinolinate (QUIN)-induced toxicity. We investigated the QUIN-induced toxic events associated with early noxious responses, which might be linked to signaling cascades leading to cell death. The extent of early cellular damage caused by this receptor in the rat striatum was characterized by image processing methods. To document the direct interaction between QUIN and RAGE, we determined the binding constant (Kb) of RAGE (VC1 domain) with QUIN through a fluorescence assay. We modeled possible binding sites of QUIN to the VC1 domain for both rat and human RAGE. QUIN was found to bind at multiple sites to the VC1 dimer, each leading to particular mechanistic scenarios for the signaling evoked by QUIN binding, some of which directly alter RAGE oligomerization. This work contributes to the understanding of the phenomenon of RAGE-QUIN recognition, leading to the modulation of RAGE function. PMID:25757085

  18. Advanced glycation end products impair function of late endothelial progenitor cells through effects on protein kinase Akt and cyclooxygenase-2

    SciTech Connect

    Chen Qin; Dong Li; Wang Lian; Kang Lina; Xu Biao

    2009-04-03

    Endothelial progenitor cells (EPCs) exhibit impaired function in the context of diabetes, and advanced glycation end products (AGEs), which accumulate in diabetes, may contribute to this. In the present study, we investigated the mechanism by which AGEs impair late EPC function. EPCs from human umbilical cord blood were isolated, and incubated with AGE-modified albumin (AGE-albumin) at different concentrations found physiologically in plasma. Apoptosis, migration, and tube formation assays were used to evaluate EPC function including capacity for vasculogenesis, and expression of the receptor for AGEs (RAGE), Akt, endothelial nitric oxide synthase (eNOS), and cycloxygenase-2 (COX-2) were determined. Anti-RAGE antibody was used to block RAGE function. AGE-albumin concentration-dependently enhanced apoptosis and depressed migration and tube formation, but did not affect proliferation, of late EPCs. High AGE-albumin increased RAGE mRNA and protein expression, and decreased Akt and COX-2 protein expression, whilst having no effect on eNOS mRNA or protein in these cells. These effects were inhibited by co-incubation with anti-RAGE antibody. These results suggest that RAGE mediates the AGE-induced impairment of late EPC function, through down-regulation of Akt and COX-2 in these cells.

  19. Levels of Soluble Receptor for Advanced Glycation End Products in Bronchoalveolar Lavage Fluid in Patients with Various Inflammatory Lung Diseases.

    PubMed

    Kamo, Tetsuro; Tasaka, Sadatomo; Tokuda, Yuriko; Suzuki, Shoji; Asakura, Takanori; Yagi, Kazuma; Namkoong, Ho; Ishii, Makoto; Hasegawa, Naoki; Betsuyaku, Tomoko

    2015-01-01

    Receptor for advanced glycation end products (RAGE) is a multiligand receptor of S100/calgranulins, high-mobility group box 1, and others, and it is associated with the pathogenesis of various inflammatory and circulatory diseases. The soluble form of RAGE (sRAGE) is a decoy receptor and competitively inhibits membrane-bound RAGE activation. In this study, we measured sRAGE levels in bronchoalveolar lavage fluid (BALF) of 78 patients, including 41 with interstitial pneumonia, 11 with sarcoidosis, 9 with respiratory infection, 7 with ARDS, 5 with lung cancer, and 5 with vasculitis. Among them, sRAGE was detectable in BALF of 73 patients (94%). In patients with ARDS and vasculitis, the sRAGE levels were significantly higher than in the control subjects and those with interstitial pneumonia. The sRAGE levels were positively correlated with total cell counts in BALF and serum levels of surfactant protein-D, lactate dehydrogenase, and C-reactive protein. There was an inverse correlation between PaO2/FIO2 ratio and sRAGE levels. These results indicate that sRAGE in BALF might be considered as a biomarker of lung inflammatory disorders, especially ARDS and vasculitis. PMID:27147899

  20. Beneficial effects of metformin and irbesartan on advanced glycation end products (AGEs)-RAGE-induced proximal tubular cell injury.

    PubMed

    Ishibashi, Yuji; Matsui, Takanori; Takeuchi, Masayoshi; Yamagishi, Sho-ichi

    2012-03-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) axis contributes to diabetic nephropathy. An oral hypoglycemic agent, metformin may have a potential effect on the inhibition of glycation reactions. Further, since a pathophysiological crosstalk between renin-angiotensin system (RAS) and AGEs-RAGE axis is involved in diabetic nephropathy, it is conceivable that metformin and irbesartan additively could protect against the AGEs-RAGE-induced tubular cell injury. In this study, we addressed the issues. Metformin dose-dependently inhibited the formation of AGEs modification of bovine serum albumin (BSA). Compared with AGEs-modified BSA prepared without metformin (AGEs-MF0), those prepared in the presence of 30 mM or 100 mM metformin (AGEs-MF30 or AGEs-MF100) significantly reduced RAGE mRNA level, reactive oxygen species (ROS) generation, apoptosis, monocyte chemoattractant protein-1 and transforming growth factor-β mRNA level in tubular cells. Irbesartan further inhibited the harmful effects of AGEs-MF0 or AGEs-MF30 on tubular cells. Our present study suggests that combination therapy with metformin and irbesartan may have therapeutic potential in diabetic nephropathy; it could play a protective role against tubular injury in diabetes not only by inhibiting AGEs formation, but also by attenuating the deleterious effects of AGEs via down-regulating RAGE expression and subsequently suppressing ROS generation. PMID:22100460

  1. Immunohistochemical distribution of the receptor for advanced glycation end products in neurons and astrocytes in Alzheimer's disease.

    PubMed

    Sasaki, N; Toki, S; Chowei, H; Saito, T; Nakano, N; Hayashi, Y; Takeuchi, M; Makita, Z

    2001-01-12

    Advanced glycation end products (AGE) and the receptor for AGE (RAGE) have been implicated in the chronic complications of diabetes mellitus (DM), and have been reported to play an important role in the pathogenesis of Alzheimer's disease (AD). In this study, we established a polyclonal anti-RAGE antibody, and examined the immunohistochemical localization of amyloid beta protein (Abeta), AGE, and RAGE in neurons and astrocytes from patients with AD and DM. Our anti-RAGE antibody recognized full-length RAGE (50 kd) and N-terminal RAGE (35 kd) in human brain tissue. Abeta-, AGE-, and RAGE-positive granules were identified in the perikaryon of hippocampal neurons (especially from CA3 and CA4) in all subjects. The distribution and staining pattern of these immunopositive granules showed good concordance with each antibody. In AD, most astrocytes contained both AGE-and RAGE-positive granules and their distribution was almost the same. Abeta-positive granules were less common, but Abeta-, AGE-, and RAGE-positive granules were colocalized in one part of a single astrocyte. In DM patients and control cases, AGE-and RAGE-positive astrocytes were very rare. These finding support the hypothesis that glycated Abeta is taken up via RAGE and is degraded through the lysosomal pathway in astrocytes. In addition to the presence of AGE, the process of AGE degradation and receptor-mediated reactions may contribute to neuronal dysfunction and promote the progression of AD. PMID:11150482

  2. Site-specific analysis of advanced glycation end products in plasma proteins of type 2 diabetes mellitus patients.

    PubMed

    Greifenhagen, Uta; Frolov, Andrej; Blüher, Matthias; Hoffmann, Ralf

    2016-08-01

    Advanced glycation end products (AGEs) are posttranslational modifications formed non-enzymatically from the reaction of carbohydrates and their degradation products with proteins. Accumulation of AGEs is associated with the progression of severe diabetic complications, for example, and elevated tissue levels of AGEs might even predict these pathologies. As AGE formation is often site-specific, mapping of these modification sites may reveal more sensitive and specific markers than the global tissue level. Here, 42 AGE modifications were identified in a bottom-up proteomic approach by tandem mass spectrometry, which corresponded to 36 sites in 22 high to medium abundant proteins in individual plasma samples obtained from type 2 diabetes mellitus (T2DM) patients with long disease duration (>10 years). Major modifications were glarg (11 modification sites) and carboxymethylation (5) of arginine and formylation (8), acetylation (7), and carboxymethylation (7) of lysine residues. Relative quantification of these sites in plasma samples obtained from normoglycemic individuals (n = 47) and patients with T2DM being newly diagnosed (n = 47) or of medium (2-5 years, n = 20) and long disease duration (>10 years, n = 20) did not reveal any significant differences. PMID:27236317

  3. Potential Dual Role of Eugenol in Inhibiting Advanced Glycation End Products in Diabetes: Proteomic and Mechanistic Insights.

    PubMed

    Singh, Priyanka; Jayaramaiah, Ramesha H; Agawane, Sachin B; Vannuruswamy, Garikapati; Korwar, Arvind M; Anand, Atul; Dhaygude, Vitthal S; Shaikh, Mahemud L; Joshi, Rakesh S; Boppana, Ramanamurthy; Kulkarni, Mahesh J; Thulasiram, Hirekodathakallu V; Giri, Ashok P

    2016-01-01

    Medicinally important genus Ocimum harbors a vast pool of chemically diverse metabolites. Current study aims at identifying anti-diabetic candidate compounds from Ocimum species. Major metabolites in O. kilimandscharicum, O. tenuiflorum, O. gratissimum were purified, characterized and evaluated for anti-glycation activity. In vitro inhibition of advanced glycation end products (AGEs) by eugenol was found to be highest. Preliminary biophysical analysis and blind docking studies to understand eugenol-albumin interaction indicated eugenol to possess strong binding affinity for surface exposed lysines. However, binding of eugenol to bovine serum albumin (BSA) did not result in significant change in secondary structure of protein. In vivo diabetic mice model studies with eugenol showed reduction in blood glucose levels by 38% likely due to inhibition of α-glucosidase while insulin and glycated hemoglobin levels remain unchanged. Western blotting using anti-AGE antibody and mass spectrometry detected notably fewer AGE modified peptides upon eugenol treatment both in vivo and in vitro. Histopathological examination revealed comparatively lesser lesions in eugenol-treated mice. Thus, we propose eugenol has dual mode of action in combating diabetes; it lowers blood glucose by inhibiting α-glucosidase and prevents AGE formation by binding to ε-amine group on lysine, protecting it from glycation, offering potential use in diabetic management. PMID:26739611

  4. Engineered glycated amino dendritic polymers as specific nonviral gene delivery vectors targeting the receptor for advanced glycation end products.

    PubMed

    Giron-Gonzalez, M Dolores; Morales-Portillo, Arturo; Salinas-Castillo, Alfonso; Lopez-Jaramillo, F Javier; Hernandez-Mateo, Fernando; Santoyo-Gonzalez, Francisco; Salto-Gonzalez, Rafael

    2014-06-18

    The receptor for advanced glycation end products (RAGE) is involved in diabetes or angiogenesis in tumors. Under pathological conditions, RAGE is overexpressed and upon ligand binding and internalization stimulates signaling pathways that promote cell proliferation. In this work, amino dendritic polymers PEI 25 kDa and alkylated derivatives of PAMAM-G2 were engineered by the nonenzymatic Maillard glycation reaction to generate novel AGE-containing gene delivery vectors targeting the RAGE. The glycated dendritic polymers were easily prepared and retained the capability to bind and protect DNA from endonucleases. Furthermore, while glycation decreased the transfection efficiency of the dendriplexes in CHO-k1 cells which do not express RAGE, glycated dendriplexes acted as efficient transfection reagents in CHO-k1 cells which stably express recombinant RAGE. In addition, preincubation with BSA-AGEs, a natural ligand of the RAGE, or dansyl cadaverine, an inhibitor of the RAGE internalization, blocked transfection, confirming their specificity toward RAGE. The results were confirmed in NRK and RAW264.7 cell lines, which naturally express the receptor. The glycated compounds retain their transfection efficiency in the presence of serum and promote in vivo transfection in a mouse model. Accordingly, RAGE is a suitable molecular target for the development of site-directed engineered glycated nonviral gene vectors. PMID:24852962

  5. Receptor for advanced glycation end products inhibits proliferation in osteoblast through suppression of Wnt, PI3K and ERK signaling

    SciTech Connect

    Li, Guofeng; Xu, Jingren; Li, Zengchun

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer RAGE overexpression suppresses cell proliferation in MC3T3-E1 cells. Black-Right-Pointing-Pointer RAGE overexpression decreases Wnt/{beta}-catenin signaling. Black-Right-Pointing-Pointer RAGE overexpression decreases ERK and PI3K signaling. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes PI3K signaling restored by RAGE blockade. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes ERK signaling restored by RAGE blockade. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a crucial role in bone metabolism. However, the role of RAGE in the control of osteoblast proliferation is not yet evaluated. In the present study, we demonstrate that RAGE overexpression inhibits osteoblast proliferation in vitro. The negative regulation of RAGE on cell proliferation results from suppression of Wnt, PI3K and ERK signaling, and is restored by RAGE neutralizing antibody. Prevention of Wnt signaling using Sfrp1 or DKK1 rescues RAGE-decreased PI3K and ERK signaling and cell proliferation, indicating that the altered cell growth in RAGE overexpressing cells is in part secondary to alterations in Wnt signaling. Consistently, RAGE overexpression inhibits the expression of Wnt targets cyclin D1 and c-myc, which is partially reversed by RAGE blockade. Overall, these results suggest that RAGE inhibits osteoblast proliferation via suppression of Wnt, PI3K and ERK signaling, which provides novel mechanisms by which RAGE regulates osteoblast growth.

  6. Levels of Soluble Receptor for Advanced Glycation End Products in Bronchoalveolar Lavage Fluid in Patients with Various Inflammatory Lung Diseases

    PubMed Central

    Kamo, Tetsuro; Tasaka, Sadatomo; Tokuda, Yuriko; Suzuki, Shoji; Asakura, Takanori; Yagi, Kazuma; Namkoong, Ho; Ishii, Makoto; Hasegawa, Naoki; Betsuyaku, Tomoko

    2015-01-01

    Receptor for advanced glycation end products (RAGE) is a multiligand receptor of S100/calgranulins, high-mobility group box 1, and others, and it is associated with the pathogenesis of various inflammatory and circulatory diseases. The soluble form of RAGE (sRAGE) is a decoy receptor and competitively inhibits membrane-bound RAGE activation. In this study, we measured sRAGE levels in bronchoalveolar lavage fluid (BALF) of 78 patients, including 41 with interstitial pneumonia, 11 with sarcoidosis, 9 with respiratory infection, 7 with ARDS, 5 with lung cancer, and 5 with vasculitis. Among them, sRAGE was detectable in BALF of 73 patients (94%). In patients with ARDS and vasculitis, the sRAGE levels were significantly higher than in the control subjects and those with interstitial pneumonia. The sRAGE levels were positively correlated with total cell counts in BALF and serum levels of surfactant protein-D, lactate dehydrogenase, and C-reactive protein. There was an inverse correlation between PaO2/FIO2 ratio and sRAGE levels. These results indicate that sRAGE in BALF might be considered as a biomarker of lung inflammatory disorders, especially ARDS and vasculitis. PMID:27147899

  7. Diet-derived advanced glycation end products or lipofuscin disrupts proteostasis and reduces life span in Drosophila melanogaster.

    PubMed

    Tsakiri, Eleni N; Iliaki, Kalliopi K; Höhn, Annika; Grimm, Stefanie; Papassideri, Issidora S; Grune, Tilman; Trougakos, Ioannis P

    2013-12-01

    Advanced glycation end product (AGE)-modified proteins are formed by the nonenzymatic glycation of free amino groups of proteins and, along with lipofuscin (a highly oxidized aggregate of covalently cross-linked proteins, sugars, and lipids), have been found to accumulate during aging and in several age-related diseases. As the in vivo effects of diet-derived AGEs or lipofuscin remain elusive, we sought to study the impact of oral administration of glucose-, fructose-, or ribose-modified albumin or of artificial lipofuscin in a genetically tractable model organism. We report herein that continuous feeding of young Drosophila flies with culture medium enriched in AGEs or in lipofuscin resulted in reduced locomotor performance and in accelerated rates of AGE-modified proteins and carbonylated proteins accumulation in the somatic tissues and hemolymph of flies, as well as in a significant reduction of flies health span and life span. These phenotypic effects were accompanied by reduced proteasome peptidase activities in both the hemolymph and the somatic tissues of flies and higher levels of oxidative stress; furthermore, oral administration of AGEs or lipofuscin in flies triggered an upregulation of the lysosomal cathepsin B, L activities. Finally, RNAi-mediated cathepsin D knockdown reduced flies longevity and significantly augmented the deleterious effects of AGEs and lipofuscin, indicating that lysosomal cathepsins reduce the toxicity of diet-derived AGEs or lipofuscin. Our in vivo studies demonstrate that chronic ingestion of AGEs or lipofuscin disrupts proteostasis and accelerates the functional decline that occurs with normal aging. PMID:23999505

  8. Contribution of the toxic advanced glycation end-products-receptor axis in nonalcoholic steatohepatitis-related hepatocellular carcinoma

    PubMed Central

    Takino, Jun-ichi; Nagamine, Kentaro; Hori, Takamitsu; Sakasai-Sakai, Akiko; Takeuchi, Masayoshi

    2015-01-01

    Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus (HCV), and non-hepatitis B/non-hepatitis C HCC (NBNC-HCC) has also been identified as an etiological factor. Although the incidence of HCV-related HCC in Japan has decreased slightly in recent years, that of NBNC-HCC has increased. The onset mechanism of NBNC-HCC, which has various etiologies, remains unclear; however, nonalcoholic steatohepatitis (NASH), a severe form of nonalcoholic fatty liver disease, is known to be an important risk factor for NBNC-HCC. Among the different advanced glycation end-products (AGEs) formed by the Maillard reaction, glyceraldehyde-derived AGEs, the predominant components of toxic AGEs (TAGE), have been associated with NASH and NBNC-HCC, including NASH-related HCC. Furthermore, the expression of the receptor for AGEs (RAGE) has been correlated with the malignant progression of HCC. Therefore, TAGE induce oxidative stress by binding with RAGE may, in turn, lead to adverse effects, such as fibrosis and malignant transformation, in hepatic stellate cells and tumor cells during NASH or NASH-related HCC progression. The aim of this review was to examine the contribution of the TAGE-RAGE axis in NASH-related HCC. PMID:26483867

  9. Role of Moesin in Advanced Glycation End Products-Induced Angiogenesis of Human Umbilical Vein Endothelial Cells

    PubMed Central

    Wang, Qian; Fan, Aihui; Yuan, Yongjun; Chen, Lixian; Guo, Xiaohua; Huang, Xuliang; Huang, Qiaobing

    2016-01-01

    Disorders of angiogenesis are related to microangiopathies during the development of diabetic vascular complications, but the effect of advanced glycation end products (AGEs) on angiogenesis and the mechanism has not been completely unveiled. We previous demonstrated that moesin belonging to the ezrin-radixin-moesin (ERM) protein family protein played a critical role in AGE-induced hyper-permeability in human umbilical vein endothelial cells (HUVECs). Here, we investigated the impact of moesin on AGE-induced HUVEC proliferation, migration, and tubulogenesis. Silencing of moesin decreased cell motility and tube formation but not cell proliferation. It also attenuated cellular F-actin reassembly. Further, phosphorylation of threonine at the 558 amino acid residue (Thr 558) in moesin suppressed AGE-induced HUVEC proliferation, migration, and tube formation, while the activating mutation of moesin at Thr 558 enhanced HUVEC angiogenesis. Further, the inhibition of either RhoA activity by adenovirus or ROCK activation with inhibitor Y27632 decreased AGE-induced moesin phosphorylation and subsequently suppressed HUVEC angiogenesis. These results indicate that the Thr 558 phosphorylation in moesin mediates endothelial angiogenesis. AGEs promoted HUVEC angiogenesis by inducing moesin phosphorylation via RhoA/ROCK pathway. PMID:26956714

  10. Litsea japonica extract inhibits neuronal apoptosis and the accumulation of advanced glycation end products in the diabetic mouse retina

    PubMed Central

    KIM, JUNGHYUN; KIM, CHAN-SIK; LEE, YUN MI; SOHN, EUNJIN; JO, KYUHYUNG; KIM, JIN SOOK

    2015-01-01

    The retinal accumulation of advanced glycation end products (AGEs) is a condition, which is found in diabetic retinopathy. The purpose of the present study was to investigate the protective effect of Litsea japonica extract (LJE) and to elucidate its underlying protective mechanism in model diabetic db/db mice. Male, 7 -week-old db/db mice were treated with LJE (100 or 250 mg/kg body weight) once a day orally for 12 weeks. The expression levels of AGEs and their receptor (RAGE) were subsequently assessed by immunohistochemistry. An electrophoretic mobility shift assay and southwestern histochemistry were used to detect activated nuclear factor κB (NF-κB). The immunohistochemical analysis demonstrated that LJE significantly reduced the expression levels of the AGEs and RAGE in the neural retinas of the db/db mice. LJE markedly inhibited the apop-tosis of retinal ganglion cells. In addition, LJE suppressed the activation of NF-κB. These results suggested that LJE may be beneficial for the treatment of diabetes-induced retinal neurodegeneration, and the ability of LJE to attenuate retinal ganglion cell loss may be mediated by inhibition of the accumulation of AGEs. PMID:25815519

  11. Advanced glycation end products induce lipogenesis: regulation by natural xanthone through inhibition of ERK and NF-κB.

    PubMed

    Mahali, Sidhartha K; Verma, Neeharika; Manna, Sunil K

    2014-12-01

    Advanced glycation end products (AGE) accumulate in diabetic patients and aged persons due to high amounts of 3- or 4-carbon derivatives of glucose. Understanding the mechanism of AGE-mediated signaling leading to these consequences, like oxidative stress, inflammation, apoptosis, etc. and its regulation would be a viable strategy to control diabetic complication and age-related diseases. We have detected the probable mechanism by which AGE increases lipogenesis, the cause of fatty liver in diabetic patients. AGE increased lipid accumulation in different cells as shown by Oil Red O staining. AGE-mediated regulation of several transcription factors was determined by gel shift assay. Antioxidants like NAC, PDTC, and vitamin C, except mangiferin, were unable to protect AGE-induced activation of SREBP and subsequent lipid accumulation. AGE increased the phosphorylation of ERK, and IKK and also DNA binding ability of SREBP, thereby its dependent gene transcription. AGE induces NF-κB which might suppress PPARγ activity, in turn reducing lipid breakdown and mobilization. Mangiferin not only inhibits AGE-mediated ROI generation that requires NF-κB activation, but also inhibits ERK and IKK activity, thereby suppression of SREBP activity and lipogenesis. Mangiferin has shown a double-edged sword effect to suppress AGE-mediated ailments by reducing ROI-mediated responses as antioxidant and inhibiting SREBP activation thereby lipogenesis, suggesting its potential efficacy against diabetes and obesity-related diseases. PMID:24733604

  12. Regulation of Receptor for Advanced Glycation End Products (RAGE) Ectodomain Shedding and Its Role in Cell Function.

    PubMed

    Braley, Alex; Kwak, Taekyoung; Jules, Joel; Harja, Evis; Landgraf, Ralf; Hudson, Barry I

    2016-06-01

    The receptor for advanced glycation end products (RAGE) is a multiligand transmembrane receptor that can undergo proteolysis at the cell surface to release a soluble ectodomain. Here we observed that ectodomain shedding of RAGE is critical for its role in regulating signaling and cellular function. Ectodomain shedding of both human and mouse RAGE was dependent on ADAM10 activity and induced with chemical activators of shedding (ionomycin, phorbol 12-myristate 13-acetate, and 4-aminophenylmercuric acetate) and endogenous stimuli (serum and RAGE ligands). Ectopic expression of the splice variant of RAGE (RAGE splice variant 4), which is resistant to ectodomain shedding, inhibited RAGE ligand dependent cell signaling, actin cytoskeleton reorganization, cell spreading, and cell migration. We found that blockade of RAGE ligand signaling with soluble RAGE or inhibitors of MAPK or PI3K blocked RAGE-dependent cell migration but did not affect RAGE splice variant 4 cell migration. We finally demonstrated that RAGE function is dependent on secretase activity as ADAM10 and γ-secretase inhibitors blocked RAGE ligand-mediated cell migration. Together, our data suggest that proteolysis of RAGE is critical to mediate signaling and cell function and may therefore emerge as a novel therapeutic target for RAGE-dependent disease states. PMID:27022018

  13. Phytochemicals from Camellia nitidissima Chi inhibited the formation of advanced glycation end-products by scavenging methylglyoxal.

    PubMed

    Wang, Weixin; Liu, Haiyan; Wang, Zhennan; Qi, Jing; Yuan, Shengtao; Zhang, Weijie; Chen, Hongjuan; Finley, John W; Gu, Liwei; Jia, Ai-Qun

    2016-08-15

    The objective of this study was to investigate the inhibitory effects of Camellia nitidissima Chi (CNC) on the advanced glycation end-product (AGE) formation. CNC was extracted with ethanol and further separated into dichloromethane, ethyl acetate, n-butanol, and water soluble fractions. Ethyl acetate fraction had the highest total phenolic and quercetin content compared with other fractions. Sixteen phenolic compounds were identified using HPLC Triple TOF MS/MS. Bovine serum albumin (BSA)-glucose assay showed that dichloromethane and ethyl acetate fraction inhibited AGE formation by 88.1% and 87.5% at 2.5mg/mL. BSA-methylglyoxal assay showed that ethyl acetate fraction inhibited 54.1% AGE formation while dichloromethane fraction inhibited 28.1%. Over 96.0% of methylglyoxal was scavenged by different fractions within 12h. Both mono- and di-methylglyoxal quercetin adducts were identified after incubating quercetin with methylglyoxal using HPLC-ESI-MS(n). The results in this study suggest that CNC extracts inhibited AGEs formation in part through scavenging methylglyoxal by phenolic compounds. PMID:27006232

  14. Fat Mass Is Inversely Associated with Serum Carboxymethyl-Lysine, An Advanced Glycation End Product, in Adults12

    PubMed Central

    Semba, Richard D.; Arab, Lenore; Sun, Kai; Nicklett, Emily J.; Ferrucci, Luigi

    2011-01-01

    High levels of circulating advanced glycation end products (AGE) are associated with cardiovascular disease, diabetes, chronic kidney disease, and increased mortality, but factors that influence levels of circulating AGE are not well known. Our objective was to characterize the relationship between serum carboxymethyl-lysine (CML), a major circulating AGE, and body composition in adults. In a cross-sectional study, total body DXA was performed and serum CML was measured in 592 adults, aged 26–93 y, from the Baltimore Longitudinal Study of Aging. Median (25th, 75th percentile) CML concentrations were 2.26 (1.86, 2.67) μmol/L. Total fat mass [β = −0.17 (95% CI −0.10, −0.24); P < 0.0001], truncal fat mass [β = −0.17 (95% CI −0.10, −0.25); P < 0.0001], and appendicular fat mass [β = −0.13 (95% CI −0.05, −0.20); P = 0.001] per 1 SD increase were inversely associated with serum CML in separate multivariate linear regression models, adjusting for age, sex, BMI, systolic blood pressure, TG, HDL cholesterol, and renal function. Lean body mass was not independently associated with serum CML. These findings suggest that serum CML concentration is strongly affected by body fat, possibly because CML is preferentially deposited in fat tissue or because adipocytes affect the metabolism of AGE. PMID:21775524

  15. Identification of the advanced glycation end products N -carboxymethyllysine in the synovial tissue of patients with rheumatoid arthritis

    PubMed Central

    Drinda, S; Franke, S; Canet, C; Petrow, P; Brauer, R; Huttich, C; Stein, G; Hein, G

    2002-01-01

    Background: Generation of advanced glycation end products (AGEs) is an inevitable process in vivo and can be accelerated under pathological conditions such as oxidative stress. In serum and synovial fluid of patients with rheumatoid arthritis (RA) raised AGE levels have been found. Objective: To determine the presence of N -carboxymethyllysine (CML; marker of oxidative stress) in RA synovial tissue by immunohistology. Methods: Frozen synovial tissue samples from 10 patients with RA and eight controls (four patients without joint disease and four patients with osteoarthritis (OA)) were treated with rabbit-anti-CML-IgG and goat-antirabbit-IgG. Immunostaining was visualised by streptavidine-alkaline phosphatase (chromogen fuchsin). Cell differentiation was performed with antibodies against CD68, CD45RO, and CD20. Results: CML was detected in the synovial lining, sublining, and endothelium in 10/10 RA and 4/4 OA synovial specimens. In RA some macrophages (CD68+) and T cells (CD45RO+) showed positive immunostaining for CML, whereas B cells were negative. Staining in OA synovial sublining was weak compared with RA. Conclusions: CML was detected for the first time in RA and OA synovial tissue. Different patterns of immunostaining in RA and OA and the presence of CML on macrophages and T cells, suggest a role for CML in the pathogenesis of RA. This might be due to presentation of new epitopes which can maintain or even trigger an autoimmune response. PMID:12006318

  16. Modeling the interaction between quinolinate and the receptor for advanced glycation end products (RAGE): relevance for early neuropathological processes.

    PubMed

    Serratos, Iris N; Castellanos, Pilar; Pastor, Nina; Millán-Pacheco, César; Rembao, Daniel; Pérez-Montfort, Ruy; Cabrera, Nallely; Reyes-Espinosa, Francisco; Díaz-Garrido, Paulina; López-Macay, Ambar; Martínez-Flores, Karina; López-Reyes, Alberto; Sánchez-García, Aurora; Cuevas, Elvis; Santamaria, Abel

    2015-01-01

    The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor involved in neurodegenerative and inflammatory disorders. RAGE induces cellular signaling upon binding to a variety of ligands. Evidence suggests that RAGE up-regulation is involved in quinolinate (QUIN)-induced toxicity. We investigated the QUIN-induced toxic events associated with early noxious responses, which might be linked to signaling cascades leading to cell death. The extent of early cellular damage caused by this receptor in the rat striatum was characterized by image processing methods. To document the direct interaction between QUIN and RAGE, we determined the binding constant (Kb) of RAGE (VC1 domain) with QUIN through a fluorescence assay. We modeled possible binding sites of QUIN to the VC1 domain for both rat and human RAGE. QUIN was found to bind at multiple sites to the VC1 dimer, each leading to particular mechanistic scenarios for the signaling evoked by QUIN binding, some of which directly alter RAGE oligomerization. This work contributes to the understanding of the phenomenon of RAGE-QUIN recognition, leading to the modulation of RAGE function. PMID:25757085

  17. Dietary Advanced Glycation End Products and Risk Factors for Chronic Disease: A Systematic Review of Randomised Controlled Trials

    PubMed Central

    Clarke, Rachel E.; Dordevic, Aimee L.; Tan, Sih Min; Ryan, Lisa; Coughlan, Melinda T.

    2016-01-01

    Dietary advanced glycation end-products (AGEs) form during heating and processing of food products and are widely prevalent in the modern Western diet. Recent systematic reviews indicate that consumption of dietary AGEs may promote inflammation, oxidative stress and insulin resistance. Experimental evidence indicates that dietary AGEs may also induce renal damage, however, this outcome has not been considered in previous systematic reviews. The purpose of this review was to examine the effect of consumption of a high AGE diet on biomarkers of chronic disease, including chronic kidney disease (CKD), in human randomized controlled trials (RCTs). Six databases (SCOPUS, CINHAL, EMBASE, Medline, Biological abstracts and Web of Science) were searched for randomised controlled dietary trials that compared high AGE intake to low AGE intake in adults with and without obesity, diabetes or CKD. Twelve dietary AGE interventions were identified with a total of 293 participants. A high AGE diet increased circulating tumour necrosis factor-alpha and AGEs in all populations. A high AGE diet increased 8-isoprostanes in healthy adults, and vascular cell adhesion molecule-1 (VCAM-1) in patients with diabetes. Markers of CKD were not widely assessed. The evidence presented indicates that a high AGE diet may contribute to risk factors associated with chronic disease, such as inflammation and oxidative stress, however, due to a lack of high quality randomised trials, more research is required. PMID:26938557

  18. Specific siRNA Targeting Receptor for Advanced Glycation End Products (RAGE) Decreases Proliferation in Human Breast Cancer Cell Lines

    PubMed Central

    Radia, AL-Madhagi; Yaser, AL-Madhagi; Ma, Xiaoqian; Zhang, Juan; Yang, Cejun; Dong, Qiong; Rong, Pengfei; Ye, Bin; Liu, Sheng; Wang, Wei

    2013-01-01

    Receptor for Advanced Glycation End Products (RAGE) is an oncogenic trans-membranous receptor overexpressed in various human cancers. However, the role of RAGE in breast cancer development and proliferation is still unclear. In this study, we demonstrated that RAGE expression levels are correlated to the degree of severity of breast cancer. Furthermore, there is a decrease in the proliferation of all sub-types of breast cancer, MCF-7, SK-Br-3 and MDA-MB-231, as a result of the effect of RAGE siRNA. RAGE siRNA arrested cells in the G1 phase and inhibited DNA synthesis (p < 0.05). Moreover, qRT-PCR and Western Blot results demonstrated that RAGE siRNA decreases the expression of transcriptional factor NF-κB p65 as well as the expression of cell proliferation markers PCNA and cyclinD1. RAGE and RAGE ligands can thus be considered as possible targets for breast cancer management and therapy. PMID:23579957

  19. Specific siRNA targeting receptor for advanced glycation end products (RAGE) decreases proliferation in human breast cancer cell lines.

    PubMed

    Radia, Al-Madhagi; Yaser, Al-Madhagi; Ma, Xiaoqian; Zhang, Juan; Yang, Cejun; Dong, Qiong; Rong, Pengfei; Ye, Bin; Liu, Sheng; Wang, Wei

    2013-01-01

    Receptor for Advanced Glycation End Products (RAGE) is an oncogenic trans-membranous receptor overexpressed in various human cancers. However, the role of RAGE in breast cancer development and proliferation is still unclear. In this study, we demonstrated that RAGE expression levels are correlated to the degree of severity of breast cancer. Furthermore, there is a decrease in the proliferation of all sub-types of breast cancer, MCF-7, SK-Br-3 and MDA-MB-231, as a result of the effect of RAGE siRNA. RAGE siRNA arrested cells in the G1 phase and inhibited DNA synthesis (p < 0.05). Moreover, qRT-PCR and Western Blot results demonstrated that RAGE siRNA decreases the expression of transcriptional factor NF-κB p65 as well as the expression of cell proliferation markers PCNA and cyclinD1. RAGE and RAGE ligands can thus be considered as possible targets for breast cancer management and therapy. PMID:23579957

  20. Inhibitory Effect of Metformin and Pyridoxamine in the Formation of Early, Intermediate and Advanced Glycation End-Products

    PubMed Central

    Ahmad, Saheem; Shahab, Uzma; Baig, Mohd. Hassan; Khan, Mohd. Sajid; Khan, M. Salman; Srivastava, A. K.; Saeed, Mohd; Moinuddin

    2013-01-01

    Background Non-enzymatic glycation is the addition of free carbonyl group of reducing sugar to the free amino groups of proteins, resulting in the formation of a Schiff base and an Amadori product. Dihydroxyacetone (DHA) is one of the carbonyl species which reacts rapidly with the free amino groups of proteins to form advanced glycation end products (AGEs). The highly reactive dihydroxyacetone phosphate is a derivative of dihydroxyacetone (DHA), and a product of glycolysis, having potential glycating effects to form AGEs. The formation of AGEs results in the generation of free radicals which play an important role in the pathophysiology of aging and diabetic complications. While the formation of DHA-AGEs has been demonstrated previously, no extensive studies have been performed to assess the inhibition of AGE inhibitors at all the three stages of glycation (early, intermediate and late) using metformin (MF) and pyridoxamine (PM) as a novel inhibitor. Methodology/Principal Findings In this study we report glycation of human serum albumin (HSA) & its characterization by various spectroscopic techniques. Furthermore, inhibition of glycation products at all the stages of glycation was also studied. Spectroscopic analysis suggests structural perturbations in the HSA as a result of modification which might be due to generation of free radicals and formation of AGEs. Conclusion The inhibition in the formation of glycation reaction reveals that Pyridoxamine is a better antiglycating agent than Metformin at all stages of the glycation (early, intermediate and late stages). PMID:24023728

  1. Potential Dual Role of Eugenol in Inhibiting Advanced Glycation End Products in Diabetes: Proteomic and Mechanistic Insights

    PubMed Central

    Singh, Priyanka; Jayaramaiah, Ramesha H.; Agawane, Sachin B.; Vannuruswamy, Garikapati; Korwar, Arvind M.; Anand, Atul; Dhaygude, Vitthal S.; Shaikh, Mahemud L.; Joshi, Rakesh S.; Boppana, Ramanamurthy; Kulkarni, Mahesh J.; Thulasiram, Hirekodathakallu V.; Giri, Ashok P.

    2016-01-01

    Medicinally important genus Ocimum harbors a vast pool of chemically diverse metabolites. Current study aims at identifying anti-diabetic candidate compounds from Ocimum species. Major metabolites in O. kilimandscharicum, O. tenuiflorum, O. gratissimum were purified, characterized and evaluated for anti-glycation activity. In vitro inhibition of advanced glycation end products (AGEs) by eugenol was found to be highest. Preliminary biophysical analysis and blind docking studies to understand eugenol-albumin interaction indicated eugenol to possess strong binding affinity for surface exposed lysines. However, binding of eugenol to bovine serum albumin (BSA) did not result in significant change in secondary structure of protein. In vivo diabetic mice model studies with eugenol showed reduction in blood glucose levels by 38% likely due to inhibition of α-glucosidase while insulin and glycated hemoglobin levels remain unchanged. Western blotting using anti-AGE antibody and mass spectrometry detected notably fewer AGE modified peptides upon eugenol treatment both in vivo and in vitro. Histopathological examination revealed comparatively lesser lesions in eugenol-treated mice. Thus, we propose eugenol has dual mode of action in combating diabetes; it lowers blood glucose by inhibiting α-glucosidase and prevents AGE formation by binding to ε-amine group on lysine, protecting it from glycation, offering potential use in diabetic management. PMID:26739611

  2. Ability of resveratrol to inhibit advanced glycation end product formation and carbohydrate-hydrolyzing enzyme activity, and to conjugate methylglyoxal.

    PubMed

    Shen, Yixiao; Xu, Zhimin; Sheng, Zhanwu

    2017-02-01

    Glycation can generate advanced glycation end products (AGE) and its intermediates methylglyoxal (MGO) and glyoxal in foods, which increase the risk of developing diabetes diseases. In this study, the effect of resveratrol against AGE formation, carbohydrate-hydrolyzing enzyme activity and trapping MGO capability were evaluated. Resveratrol showed a significant inhibition capability against AGE formation in bovine serum albumin (BSA)-fructose, BSA-MGO and arginine-MGO models with inhibition percentages of 57.94, 85.95 and 99.35%, respectively. Furthermore, resveratrol acted as a competitive inhibitor for α-amylase with IC50 3.62μg/ml, while it behaved in an uncompetitive manner for α-glucosidase with an IC50 of 17.54μg/l. A prevention of BSA protein glycation was observed in the BSA-fructose model with addition of resveratrol. Three types of resveratrol-MGO adducts were identified in the model consisting of MGO and resveratrol. The results demonstrated that resveratrol has potential in reducing glycation in foods and retarding carbohydrate-hydrolyzing enzyme activities. PMID:27596404

  3. UVA Light-excited Kynurenines Oxidize Ascorbate and Modify Lens Proteins through the Formation of Advanced Glycation End Products

    PubMed Central

    Linetsky, Mikhail; Raghavan, Cibin T.; Johar, Kaid; Fan, Xingjun; Monnier, Vincent M.; Vasavada, Abhay R.; Nagaraj, Ram H.

    2014-01-01

    Advanced glycation end products (AGEs) contribute to lens protein pigmentation and cross-linking during aging and cataract formation. In vitro experiments have shown that ascorbate (ASC) oxidation products can form AGEs in proteins. However, the mechanisms of ASC oxidation and AGE formation in the human lens are poorly understood. Kynurenines are tryptophan oxidation products produced from the indoleamine 2,3-dioxygenase (IDO)-mediated kynurenine pathway and are present in the human lens. This study investigated the ability of UVA light-excited kynurenines to photooxidize ASC and to form AGEs in lens proteins. UVA light-excited kynurenines in both free and protein-bound forms rapidly oxidized ASC, and such oxidation occurred even in the absence of oxygen. High levels of GSH inhibited but did not completely block ASC oxidation. Upon UVA irradiation, pigmented proteins from human cataractous lenses also oxidized ASC. When exposed to UVA light (320–400 nm, 100 milliwatts/cm2, 45 min to 2 h), young human lenses (20–36 years), which contain high levels of free kynurenines, lost a significant portion of their ASC content and accumulated AGEs. A similar formation of AGEs was observed in UVA-irradiated lenses from human IDO/human sodium-dependent vitamin C transporter-2 mice, which contain high levels of kynurenines and ASC. Our data suggest that kynurenine-mediated ASC oxidation followed by AGE formation may be an important mechanism for lens aging and the development of senile cataracts in humans. PMID:24798334

  4. Recent Advances in Transition Metal-Catalyzed Glycosylation

    PubMed Central

    McKay, Matthew J.; Nguyen, Hien M.

    2012-01-01

    Having access to mild and operationally simple techniques for attaining carbohydrate targets will be necessary to facilitate advancement in biological, medicinal, and pharmacological research. Even with the abundance of elegant reports for generating glycosidic linkages, stereoselective construction of α- and β-oligosaccharides and glycoconjugates is by no means trivial. In an era where expanded awareness of the impact we are having on the environment drives the state-of-the-art, synthetic chemists are tasked with developing cleaner and more efficient reactions for achieving their transformations. This movement imparts the value that prevention of waste is always superior to its treatment or cleanup. This review will highlight recent advancement in this regard by examining strategies that employ transition metal catalysis in the synthesis of oligosaccharides and glycoconjugates. These methods are mild and effective for constructing glycosidic bonds with reduced levels of waste through utilization of sub-stoichiometric amounts of transition metals to promote the glycosylation. PMID:22924154

  5. Advanced glycation end products induce peroxisome proliferator-activated receptor γ down-regulation-related inflammatory signals in human chondrocytes via Toll-like receptor-4 and receptor for advanced glycation end products.

    PubMed

    Chen, Ying Ju; Sheu, Meei Ling; Tsai, Keh Sung; Yang, Rong Sen; Liu, Shing Hwa

    2013-01-01

    Accumulation of advanced glycation end products (AGEs) in joints is important in the development of cartilage destruction and damage in age-related osteoarthritis (OA). The aim of this study was to investigate the roles of peroxisome proliferator-activated receptor γ (PPARγ), toll-like receptor 4 (TLR4), and receptor for AGEs (RAGE) in AGEs-induced inflammatory signalings in human OA chondrocytes. Human articular chondrocytes were isolated and cultured. The productions of metalloproteinase-13 and interleukin-6 were quantified using the specific ELISA kits. The expressions of related signaling proteins were determined by Western blotting. Our results showed that AGEs enhanced the productions of interleukin-6 and metalloproteinase-13 and the expressions of cyclooxygenase-2 and high-mobility group protein B1 and resulted in the reduction of collagen II expression in human OA chondrocytes. AGEs could also activate nuclear factor (NF)-κB activation. Stimulation of human OA chondrocytes with AGEs significantly induced the up-regulation of TLR4 and RAGE expressions and the down-regulation of PPARγ expression in a time- and concentration-dependent manner. Neutralizing antibodies of TLR4 and RAGE effectively reversed the AGEs-induced inflammatory signalings and PPARγ down-regulation. PPARγ agonist pioglitazone could also reverse the AGEs-increased inflammatory signalings. Specific inhibitors for p38 mitogen-activated protein kinases, c-Jun N-terminal kinase and NF-κB suppressed AGEs-induced PPARγ down-regulation and reduction of collagen II expression. Taken together, these findings suggest that AGEs induce PPARγ down-regulation-mediated inflammatory signalings and reduction of collagen II expression in human OA chondrocytes via TLR4 and RAGE, which may play a crucial role in the development of osteoarthritis pathogenesis induced by AGEs accumulation. PMID:23776688

  6. Association of polymorphisms of the receptor for advanced glycation end products gene with COPD in the Chinese population.

    PubMed

    Li, You; Yang, Cheng; Ma, Guoda; Gu, Xuefeng; Chen, Min; Chen, Yanyan; Zhao, Bin; Cui, Lili; Li, Keshen

    2014-04-01

    The receptor for advanced glycation end products (RAGE) is a cell surface molecule of the immunoglobulin superfamily that binds diverse endogenous ligands involved in the development of chronic diseases and inflammatory damage. A growing body of evidence has suggested that RAGE is involved in the development and progression of chronic obstructive pulmonary disease (COPD). The present study investigated the existence of an association among three polymorphisms (-374T/A, -429T/C, and G82S) of the RAGE gene with the risk of COPD in the Chinese population. The RAGE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism in 216 patients with COPD and 239 age-matched healthy individuals. Our study demonstrated that the frequencies of the GS genotype and the S allele in the G82S mutation were significantly higher in COPD patients than in controls (odds ratios [OR]=1.70, 95% confidence interval [CI]: 1.15-2.50, p=0.0098 and OR=1.42, 95% CI: 1.06-1.91, p=0.023, respectively). Further stratification analysis by smoking status revealed that the presence of the GS genotype conferred a higher risk of developing COPD in current smokers (p=0.044). In contrast, mutations at -374T/A and -429T/C did not demonstrate any association with COPD, even after taking into account the patients' smoking history. Our study provides preliminary evidence that the G82S polymorphism in the RAGE gene is associated with an increased risk of COPD and that the GS genotype of the G82S variant is a risk factor for COPD in the Chinese population. PMID:24520905

  7. The advanced glycation end product-lowering agent ALT-711 is a low-affinity inhibitor of thiamine diphosphokinase.

    PubMed

    Krautwald, Martina; Leech, Dale; Horne, Stacey; Steele, Megan L; Forbes, Josephine; Rahmadi, Anton; Griffith, Renate; Münch, Gerald

    2011-08-01

    Advanced glycation end products (AGEs) are involved in age-related diseases, including the complications of diabetes and chronic renal impairment with arterial stiffening. Alagebrium chloride (ALT-711) is an AGE-lowering agent with beneficial effects in renal structural and functional parameters in diabetes, decreased diabetes-accelerated atherosclerosis, and age-related myocardial stiffening. ALT-711 exhibits a structural homology to thiamine, and it was suggested to interfere with thiamine metabolism. Thiamine is converted to thiamine diphosphate (TDP) by thiamine diphosphokinase (TDPK). TDP is a cofactor for pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and transketolase. A decreased activity of these enzymes due to TDP deficiency results in disorders such as beriberi and Wernicke-Korsakoff syndrome. Therefore, we investigated whether ALT-711 is an inhibitor of TDPK. Molecular modeling studies showed that ALT-711 fits into the thiamine-binding pocket of TDPK, and there are three interactions between the thiazolium ring and the enzyme, as well as parallel stacking between the phenyl ring and the indole ring of Trp222B. Enzyme kinetic experiments also showed that ALT-711 dose-dependently decreased TDPK activity with K(i)s, calculated by different experiments and fitting models ranging from 0.88 to 1.09 mM. Fitting of the kinetic data favored mixed-mode inhibition with a major role for competitive inhibition. In summary, our results suggest that ALT-711 is a low-affinity inhibitor of TDPK, but is unlikely to interfere with thiamine metabolism at therapeutic concentrations. However, when new AGE-crosslink breakers based on thiamine are designed, care should be taken that they do not act as more potent competitive inhibitors than ALT-711. PMID:21612515

  8. Effect of advanced glycation end products, extracellular matrix metalloproteinase inducer and matrix metalloproteinases on type-I collagen metabolism

    PubMed Central

    LI, WANG; LING, WANG; TENG, XIAOMEI; QUAN, CUIXIA; CAI, SHENGNAN; HU, SHUQUN

    2016-01-01

    The aim of the study was to examine the association among advanced glycation end products (AGEs), extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinase (MMPs), and investigate whether AGEs affect type I collagen (COL-I) through EMMPRIN or MMPs. A co-culture system with the osteoblast-like cells (MC3T3E1) and mouse RAW264.7 cells was employed to examine the effects of AGE-bovine serum albumin (BSA) (50 mg/l), EMMPRIN antibody (5 mg/l) and AGE-BSA+EMMPRIN antibody separately on COL-I expression for 24 h. Culture media were analyzed for the content of COL-I by ELISA. The effect of different concentrations of AGE-BSA (0, 50, 100, 200 and 400 mg/l) for 24 h was assessed on COL-I levels. Finally, semiquantitative RT-PCR was used to detect the osteoblast COL-I mRNA expression and MMP-2 and MMP-9's PMAO were also measured in the culture medium. COL-I content in the culture medium decreased significantly following treatment with AGE-BSA (P<0.05). EMMPRIN antibody increased COL-I content (P<0.05). EMMPRIN antibody+AGE-BSA increased COL-I significantly (P<0.05). Different concentrations of AGE-BSA increased COL-I mRNA expression significantly compared with the control group (P<0.05), and were enhanced with increasing AGE-BSA concentration (P<0.05). Also MMP-2 and MMP-9 secretion increased significantly (P<0.05), with the increasing AGE-BSA concentration. In conclusion, an increase in AGE levels in vitro stimulates the secretion of EMMPRIN/MMPs, promotes the degradation of COL-I and reduces bone strength. PMID:27284408

  9. Central and peripheral blood pressures in relation to plasma advanced glycation end products in a Chinese population.

    PubMed

    Huang, Q-F; Sheng, C-S; Kang, Y-Y; Zhang, L; Wang, S; Li, F-K; Cheng, Y-B; Guo, Q-H; Li, Y; Wang, J-G

    2016-07-01

    We investigated the association of plasma AGE (advanced glycation end product) concentration with central and peripheral blood pressures and central-to-brachial blood pressure amplification in a Chinese population. The study subjects were from a newly established residential area in the suburb of Shanghai. Using the SphygmoCor system, we recorded radial arterial waveforms and derived aortic waveforms by a generalized transfer function and central systolic and pulse pressure by calibration for brachial blood pressure measured with an oscillometric device. The central-to-brachial pressure amplification was expressed as the central-to-brachial systolic blood pressure difference and pulse pressure difference and ratio. Plasma AGE concentration was measured by the enzyme-linked immunosorbent assay method and logarithmically transformed for statistical analysis. The 1051 participants (age, 55.1±13.1 years) included 663 women. After adjustment for sex, age and other confounding factors, plasma AGE concentration was associated with central but not peripheral blood pressures and with some of the pressure amplification indexes. Indeed, each 10-fold increase in plasma AGE concentration was associated with 2.94 mm Hg (P=0.04) higher central systolic blood pressure and 2.39% lower central-to-brachial pulse pressure ratio (P=0.03). In further subgroup analyses, the association was more prominent in the presence of hypercholesterolemia (+8.11 mm Hg, P=0.008) for central systolic blood pressure and in the presence of overweight and obesity (-4.89%, P=0.009), diabetes and prediabetes (-6.26%, P=0.10) or current smoking (-6.68%, P=0.045) for central-to-brachial pulse pressure ratio. In conclusion, plasma AGE concentration is independently associated with central systolic blood pressure and pulse pressure amplification, especially in the presence of several modifiable cardiovascular risk factors. PMID:26084655

  10. Correlation between advanced glycation end-products and the expression of fatty inflammatory factors in type II diabetic cardiomyopathy

    PubMed Central

    Guo, Zhengdong; Huang, Donghui; Tang, Xiange; Han, Jingjing; Li, Jing

    2015-01-01

    Diabetic cardiomyopathy (DCM) is one of the most severe complications of diabetes without a clear pathogenesis. This study investigated the adiponectin (APN) and leptin levels in type II DCM, as well as their correlation with advanced glycation end-products (AGEs). From 2011–2013, 78 type II diabetes mellitus (T2DM) cases (40–65 years old) in the Taian region were randomly selected. Based on the results of colour Doppler ultrasonography and coronary angiography, the cases were divided into a simple T2DM group (40 cases) and a DCM group (38 cases). Forty healthy subjects were used as normal control (NC). An enzyme-linked immunosorbent assay was performed to determine the levels of fatty inflammatory factors such as APN, leptin and AGEs, and a correlation analysis was conducted. In the T2DM group, the APN levels were decreased but the leptin and AGE levels were significantly increased compared to the NC group. In the DCM group, the APN levels were decreased but the leptin and AGE levels were significantly increased (P<0.01) compared to the T2DM group. The AGE levels were positively correlated with disease progression and with fasting plasma glucose levels, glycated haemoglobin, insulin resistance and leptin, but were negatively correlated with APN levels. Additionally, the APN and leptin levels were independently related to the AGE levels. Fatty inflammatory factors play a significant role in the progression of both simple T2DM and DCM. The results of this study revealed the pathogenesis of DCM and indicated the potential significance of AGEs in DCM prevention and treatment. PMID:26614846

  11. Modulation of soluble receptor for advanced glycation end products by angiotensin-converting enzyme-1 inhibition in diabetic nephropathy.

    PubMed

    Forbes, Josephine M; Thorpe, Suzanne R; Thallas-Bonke, Vicki; Pete, Josefa; Thomas, Merlin C; Deemer, Elizabeth R; Bassal, Sahar; El-Osta, Assam; Long, David M; Panagiotopoulos, Sianna; Jerums, George; Osicka, Tanya M; Cooper, Mark E

    2005-08-01

    Recent studies have identified that first-line renoprotective agents that interrupt the renin-angiotensin system not only reduce BP but also can attenuate advanced glycation end product (AGE) accumulation. This study used in vitro, preclinical, and human approaches to explore the potential effects of these agents on the modulation of the receptor for AGE (RAGE). Bovine aortic endothelial cells that were exposed to the angiotensin-converting enzyme inhibitor (ACEi) ramiprilat in the presence of high glucose demonstrated a significant increase in soluble RAGE (sRAGE) secreted into the medium. In streptozotocin-induced diabetic rats, ramipril treatment (ACEi) at 3 mg/L for 24 wk reduced the accumulation of skin collagen-linked carboxymethyllysine and pentosidine, as well as circulating and renal AGE. Renal gene upregulation of total RAGE (all three splice variants) was observed in ACEi-treated animals. There was a specific increase in the gene expression of the splice variant C-truncated RAGE (sRAGE). There were also increases in sRAGE protein identified within renal cells with ACEi treatment, which showed AGE-binding ability. This was associated with decreases in renal full-length RAGE protein from ACEi-treated rats. Decreases in plasma soluble RAGE that were significantly increased by ACEi treatment were also identified in diabetic rats. Similarly, there was a significant increase in plasma sRAGE in patients who had type 1 diabetes and were treated with the ACEi perindopril. Complexes between sRAGE and carboxymethyllysine were identified in human and rodent diabetic plasma. It is postulated that ACE inhibition reduces the accumulation of AGE in diabetes partly by increasing the production and secretion of sRAGE into plasma. PMID:15930093

  12. Enhanced cellular oxidant stress by the interaction of advanced glycation end products with their receptors/binding proteins.

    PubMed

    Yan, S D; Schmidt, A M; Anderson, G M; Zhang, J; Brett, J; Zou, Y S; Pinsky, D; Stern, D

    1994-04-01

    Attack by reactive oxygen intermediates, common to many kinds of cell/tissue injury, has been implicated in the development of diabetic and other vascular diseases. Such oxygen-free radicals can be generated by advanced glycation end products (AGEs), which are nonenzymatically glycated and oxidized proteins. Since cellular interactions of AGEs are mediated by specific cellular binding proteins, receptor for AGE (RAGE) and the lactoferrin-like polypeptide (LF-L), we tested the hypothesis that AGE ligands tethered to the complex of RAGE and LF-L could induce oxidant stress. AGE albumin or AGEs immunoisolated from diabetic plasma resulted in induction of endothelial cell (EC) oxidant stress, including the generation of thiobarbituric acid reactive substances (TBARS) and resulted in the activation of NF-kappa B, each of which was blocked by antibodies to AGE receptor polypeptides and by antioxidants. Infusion of AGE albumin into normal animals led to the appearance of malondialdehyde determinants in the vessel wall and increased TBARS in the tissues, activation of NF-kappa B, and induction of heme oxygenase mRNA. AGE-induced oxidant stress was inhibited by pretreatment of animals with either antibodies to the AGE receptor/binding proteins or antioxidants. These data indicate that interaction of AGEs with cellular targets, such as ECs, leads to oxidant stress resulting in changes in gene expression and other cellular properties, potentially contributing to the development of vascular lesions. Further studies will be required to dissect whether oxidant stress occurs on the cell surface or at an intracellular locus. PMID:8144582

  13. Phlorotannins from Brown Algae: inhibition of advanced glycation end products formation in high glucose induced Caenorhabditis elegans.

    PubMed

    Shakambari, Ganeshan; Ashokkumar, Balasubramaniem; Varalakshmi, Perumal

    2015-06-01

    Advanced Glycation End products (AGE) generated in a non enzymatic protein glycation process are frequently associated with diabetes, aging and other chronic diseases. Here, we explored the protective effect of phlorotannins from brown algae Padina pavonica, Sargassum polycystum and Turbinaria ornata against AGEs formation. Phlorotannins were extracted from brown algae with methanol and its purity was analyzed by TLC and RP-HPLC-DAD. Twenty five grams of P. pavonica, S. polycystum, T. ornata yielded 27.6 ± 0.8 μg/ml, 37.7 μg/ml and 37.1 ± 0.74 μg/ml of phloroglucinol equivalent of phlorotannins, respectively. Antioxidant potentials were examined through DPPH assay and their IC50 values were P. pavonica (30.12 ± 0.99 μg), S. polycystum (40.9 ± 1.2 μg) and T. ornata (22.9 ± 1.3 μg), which was comparatively lesser than the control ascorbic acid (46 ± 0.2 μg). Further, anti-AGE activity was examined in vitro by BSA-glucose assay with the extracted phlorotannins of brown algae (P. pavonica, 15.16 ± 0.26 μg/ml; S. polycystum, 35.245 ± 2.3 μg/ml; T. ornata, 22.7 ± 0.3 μg/ml), which revealed the required concentration to inhibit 50% of albumin glycation (IC50) were lower for extracts than controls (phloroglucinol, 222.33 ± 4.9 μg/ml; thiamine, 263 μg/ml). Furthermore, brown algal extracts containing phlorotannins (100 μl) exhibited protective effects against AGE formation in vivo in C. elegans with induced hyperglycemia. PMID:26155677

  14. Regulation of human mononuclear phagocyte migration by cell surface-binding proteins for advanced glycation end products.

    PubMed Central

    Schmidt, A M; Yan, S D; Brett, J; Mora, R; Nowygrod, R; Stern, D

    1993-01-01

    Nonenzymatic glycation of proteins occurs at an accelerated rate in diabetes and can lead to the formation of advanced glycation end products of proteins (AGEs), which bind to mononuclear phagocytes (MPs) and induce chemotaxis. We have isolated two cell surface-associated binding proteins that mediate the interaction of AGEs with bovine endothelial cells. One of these proteins is a new member of the immunoglobulin superfamily of receptors (termed receptor for AGEs or RAGE); and the second is a lactoferrin-like polypeptide (LF-L). Using monospecific antibodies to these two AGE-binding proteins, we detected immunoreactive material on Western blots of detergent extracts from human MPs. Radioligand-binding studies demonstrated that antibody to the binding proteins blocked 125I-AGE-albumin binding and endocytosis by MPs. Chemotaxis of human MPs induced by soluble AGE-albumin was prevented in a dose-dependent manner by intact antibodies raised to the AGE-binding proteins, F(ab')2 fragments of these antibodies and by soluble RAGE. When MP migration in response to N-formyl-Met-Leu-Phe was studied in a chemotaxis chamber with AGE-albumin adsorbed to the upper surface of the chamber membrane, movement of MPs to the lower compartment was decreased because of interaction of the glycated proteins with RAGE and LF-L on the cell surface. The capacity of AGEs to attract and retain MPs was shown by implanting polytetrafluoroethylene (PTFE) mesh impregnated with AGE-albumin into rats: within 4 d a florid mononuclear cell infiltrate was evident in contrast to the lack of a significant cellular response to PTFE with adsorbed native albumin. These data indicate that RAGE and LF-L have a central role in the interaction of AGEs with human mononuclear cells and that AGEs can serve as a nidus to attract MPs in vivo. Images PMID:8387541

  15. Glucitol-core containing gallotannins inhibit the formation of advanced glycation end-products mediated by their antioxidant potential.

    PubMed

    Ma, Hang; Liu, Weixi; Frost, Leslie; Kirschenbaum, Louis J; Dain, Joel A; Seeram, Navindra P

    2016-05-18

    Glucitol-core containing gallotannins (GCGs) are polyphenols containing galloyl groups attached to a 1,5-anhydro-d-glucitol core, which is uncommon among naturally occurring plant gallotannins. GCGs have only been isolated from maple (Acer) species, including the red maple (Acer rubrum), a medicinal plant which along with the sugar maple (Acer saccharum), are the major sources of the natural sweetener, maple syrup. GCGs are reported to show antioxidant, α-glucosidase inhibitory, and antidiabetic effects, but their antiglycating potential is unknown. Herein, the inhibitory effects of five GCGs (containing 1-4 galloyls) on the formation of advanced glycation end-products (AGEs) were evaluated by MALDI-TOF mass spectroscopy, and BSA-fructose, and G.K. peptide-ribose assays. The GCGs showed superior activities compared to the synthetic antiglycating agent, aminoguanidine (IC50 15.8-151.3 vs. >300 μM) at the early, middle, and late stages of glycation. Circular dichroism data revealed that the GCGs were able to protect the secondary structure of BSA protein from glycation. The GCGs did not inhibit AGE formation by the trapping of reactive carbonyl species, namely, methylglyoxal, but showed free radical scavenging activities in the DPPH assay. The free radical quenching properties of the GCGs were further confirmed by electron paramagnetic resonance spectroscopy using ginnalin A (contains 2 galloyls) as a representative GCG. In addition, this GCG chelated ferrous iron, an oxidative catalyst of AGE formation, supported a potential antioxidant mechanism of antiglycating activity for these polyphenols. Therefore, GCGs should be further investigated for their antidiabetic potential given their antioxidant, α-glucosidase inhibitory, and antiglycating properties. PMID:27101975

  16. Association of Polymorphisms of the Receptor for Advanced Glycation End Products Gene with COPD in the Chinese Population

    PubMed Central

    Li, You; Yang, Cheng; Ma, Guoda; Gu, Xuefeng; Chen, Min; Chen, Yanyan; Zhao, Bin

    2014-01-01

    The receptor for advanced glycation end products (RAGE) is a cell surface molecule of the immunoglobulin superfamily that binds diverse endogenous ligands involved in the development of chronic diseases and inflammatory damage. A growing body of evidence has suggested that RAGE is involved in the development and progression of chronic obstructive pulmonary disease (COPD). The present study investigated the existence of an association among three polymorphisms (−374T/A, −429T/C, and G82S) of the RAGE gene with the risk of COPD in the Chinese population. The RAGE genotypes were determined by polymerase chain reaction–restriction fragment length polymorphism in 216 patients with COPD and 239 age-matched healthy individuals. Our study demonstrated that the frequencies of the GS genotype and the S allele in the G82S mutation were significantly higher in COPD patients than in controls (odds ratios [OR]=1.70, 95% confidence interval [CI]: 1.15–2.50, p=0.0098 and OR=1.42, 95% CI: 1.06–1.91, p=0.023, respectively). Further stratification analysis by smoking status revealed that the presence of the GS genotype conferred a higher risk of developing COPD in current smokers (p=0.044). In contrast, mutations at −374T/A and −429T/C did not demonstrate any association with COPD, even after taking into account the patients' smoking history. Our study provides preliminary evidence that the G82S polymorphism in the RAGE gene is associated with an increased risk of COPD and that the GS genotype of the G82S variant is a risk factor for COPD in the Chinese population. PMID:24520905

  17. Differential expression of receptors for advanced glycation end-products in peritoneal mesothelial cells exposed to glucose degradation products

    PubMed Central

    LAI, K N; LEUNG, J C K; CHAN, L Y Y; LI, F F K; TANG, S C W; LAM, M F; TSE, K C; YIP, T P; CHAN, T M; WIESLANDER, A; VLASSARA, H

    2004-01-01

    Autoclaving peritoneal dialysate fluid (PDF) degrades glucose into glucose degradation products (GDPs) that impair peritoneal mesothelial cell functions. While glycation processes leading to formation of advanced glycation end-products (AGE) were viewed commonly as being mediated by glucose present in the PDF, recent evidence indicates that certain GDPs are even more powerful inducers of AGE formation than glucose per se. In the present study, we examined the expression and modulation of AGE receptors on human peritoneal mesothelial cells (HPMC) cultured with GDPs, conventional PDF or PDF with low GDP content. HPMC cultured with GDPs differentially modulated AGE receptors (including RAGE, AGE–R1, AGE–R2 and AGE–R3) expression in a dose-dependent manner. At subtoxic concentrations, GDPs increased RAGE mRNA expression in HPMC. 2-furaldehyde (FurA), methylglyoxal (M-Glx) and 3,4-dideoxy-glucosone-3-Ene (3,4-DGE) increased the expression of AGE–R1 and RAGE, the receptors that are associated with toxic effects. These three GDPs up-regulated the AGE synthesis by cultured HPMC. In parallel, these GDPs also increased the expression of vascular endothelial growth factor (VEGF) in HPMC. PDF with lower GDP content exerted less cytotoxic effect than traditional heat-sterilized PDF. Both PDF preparations up-regulated the protein expression of RAGE and VEGF. However, the up-regulation of VEGF in HPMC following 24-h culture with conventional PDF was higher than values from HPMC cultured with PDF containing low GDP. We have demonstrated, for the first time, that in addition to RAGE, other AGE receptors including AGE–R1, AGE–R2 and AGE–R3 are expressed on HPMC. Different GDPs exert differential regulation on the expression of these receptors on HPMC. The interactions between GDPs and AGE receptors may bear biological relevance to the intraperitoneal homeostasis and membrane integrity. PMID:15544624

  18. Advanced Glycation End Products Impair Voltage-Gated K+ Channels-Mediated Coronary Vasodilation in Diabetic Rats

    PubMed Central

    Su, Wen; Li, Weiping; Chen, Hui; Liu, Huirong; Huang, Haixia; Li, Hongwei

    2015-01-01

    Background We have previously reported that high glucose impairs coronary vasodilation by reducing voltage-gated K+ (Kv) channel activity. However, the underlying mechanisms remain unknown. Advanced glycation end products (AGEs) are potent factors that contribute to the development of diabetic vasculopathy. The aim of this study was to investigate the role of AGEs in high glucose-induced impairment of Kv channels-mediated coronary vasodilation. Methods Patch-clamp recording and molecular biological techniques were used to assess the function and expression of Kv channels. Vasodilation of isolated rat small coronary arteries was measured using a pressurized myograph. Treatment of isolated coronary vascular smooth muscle cells (VSMCs) and streptozotocin-induced diabetic rats with aminoguanidine, the chemical inhibitor of AGEs formation, was performed to determine the contribution of AGEs. Results Incubation of VSMCs with high glucose reduced Kv current density by 60.4 ± 4.8%, and decreased expression of Kv1.2 and Kv1.5 both at the gene and protein level, whereas inhibiting AGEs formation or blocking AGEs interacting with their receptors prevented high glucose-induced impairment of Kv channels. In addition, diabetic rats manifested reduced Kv channels-mediated coronary dilation (9.3 ± 1.4% vs. 36.9 ± 1.4%, P < 0.05), which was partly corrected by the treatment with aminoguanidine (24.4 ± 2.2% vs. 9.3 ± 1.4%, P < 0.05). Conclusions Excessive formation of AGEs impairs Kv channels in VSMCs, then leading to attenuation of Kv channels-mediated coronary vasodilation. PMID:26562843

  19. Chronic Ingestion of Advanced Glycation End Products Induces Degenerative Spinal Changes and Hypertrophy in Aging Pre-Diabetic Mice

    PubMed Central

    Illien-Jünger, Svenja; Lu, Young; Qureshi, Sheeraz A.; Hecht, Andrew C.; Cai, Weijing; Vlassara, Helen; Striker, Gary E.; Iatridis, James C.

    2015-01-01

    Intervertebral disc (IVD) degeneration and pathological spinal changes are major causes of back pain, which is the top cause of global disability. Obese and diabetic individuals are at increased risk for back pain and musculoskeletal complications. Modern diets contain high levels of advanced glycation end products (AGEs), cyto-toxic components which are known contributors to obesity, diabetes and accelerated aging pathologies. There is little information about potential effects of AGE rich diet on spinal pathology, which may be a contributing cause for back pain which is common in obese and diabetic individuals. This study investigated the role of specific AGE precursors (e.g. methylglyoxal-derivatives (MG)) on IVD and vertebral pathologies in aging C57BL6 mice that were fed isocaloric diets with standard (dMG+) or reduced amounts of MG derivatives (dMG-; containing 60-70% less dMG). dMG+ mice exhibited a pre-diabetic phenotype, as they were insulin resistant but not hyperglycemic. Vertebrae of dMG+ mice displayed increased cortical-thickness and cortical-area, greater MG-AGE accumulation and ectopic calcification in vertebral endplates. IVD morphology of dMG+ mice exhibited ectopic calcification, hypertrophic differentiation and glycosaminoglycan loss relative to dMG- mice. Overall, chronic exposure to dietary AGEs promoted age-accelerated IVD degeneration and vertebral alterations involving ectopic calcification which occurred in parallel with insulin resistance, and which were prevented with dMG- diet. This study described a new mouse model for diet-induced spinal degeneration, and results were in support of the hypothesis that chronic AGE ingestion could be a factor contributing to a pre-diabetic state, ectopic calcifications in spinal tissues, and musculoskeletal complications that are more generally known to occur with chronic diabetic conditions. PMID:25668621

  20. Serum carboxymethyl-lysine, an advanced glycation end product, is associated with arterial stiffness in older adults

    PubMed Central

    SEMBA, Richard D.; SUN, Kai; SCHWARTZ, Ann V.; VARADHAN, Ravi; HARRIS, Tamara B.; SATTERFIELD, Suzanne; GARCIA, Melissa; FERRUCCI, Luigi; NEWMAN, Anne B.

    2015-01-01

    Objective To examine the relationship of serum carboxymethyl-lysine (CML), an advanced glycation end product (AGE), with pulse pressure (PP), aortic pulse wave velocity (aPWV), and hypertension in older adults. Background AGEs are bioactive molecules that accumulate in tissues with aging and can both cross-link collagen and induce inflammation in model systems. The relationship of AGEs with arterial stiffness and hypertension has not been well characterized in community-dwelling older adults. Methods We measured serum CML and blood pressure in 3044 adults, aged 70–79 y, who participated in the Health, Aging and Body Composition Study, a population-based study of aging in Pittsburgh, Pennsylvania, and Memphis, Tennessee. aPWV was measured in 2468 participants. Results Participants in the highest tertile of serum CML had higher PP (highest tertile: beta = 2.85, SE = 0.82, P = 0.0005; middle tertile: beta = 0.60, SE = 0.80, P = 0.45), and higher aPWV (highest tertile: beta = 51.4, SE = 20.1, P = 0.01; middle tertile: beta = 3.2, SE = 19.8, P = 0.87) compared with those in the lowest tertile in multivariable linear regression models adjusting for age, sex, race, education, BMI, smoking, alcohol use, total cholesterol, HDL cholesterol, diabetes, cardiovascular disease, and chronic kidney disease. Participants in the highest and middle tertiles of serum CML had higher odds of hypertension (Odds Ratio [O.R.] 1.32, 95% Confidence Interval [C.I.] 1.06, 1.60, P = 0.005; O.R. 1.27, 95% C.I. 1.05, 1.53, P = 0.01, respectively) compared with the lowest tertile in a multivariable logistic regression model adjusting for the same covariates. Conclusions Elevated serum CML was associated with arterial stiffness, as reflected by higher PP and aPWV, in older, community-dwelling adults. PMID:25915884

  1. Aspartic acid functions as carbonyl trapper to inhibit the formation of advanced glycation end products by chemical chaperone activity.

    PubMed

    Prasanna, Govindarajan; Saraswathi, N T

    2016-05-01

    Advanced glycation end products (AGEs) were implicated in pathology of numerous diseases. In this study, we present the bioactivity of aspartic acid (Asp) to inhibit the AGEs. Hemoglobin and bovine serum albumin (BSA) were glycated with glucose, fructose, and ribose in the presence and absence of Asp (100-200 μM). HbA1c inhibition was investigated using human blood and characterized by micro-column ion exchange chromatography. The effect of methyl glyoxal (MG) on hemoglobin and BSA was evaluated by fluorescence spectroscopy and gel electrophoresis. The effect of MG on red blood cells morphology was characterized by scanning electron micrographs. Molecular docking was performed on BSA with Asp. Asp is capable of inhibiting the formation of fluorescent AGEs by reacting with the reducing sugars. The presence of Asp as supplement in whole blood reduced the HbA1c% from 8.8 to 6.1. The presence of MG showed an increase in fluorescence and the presence of Asp inhibited the glycation thereby the fluorescence was quenched. MG also affected the electrophoretic mobility of hemoglobin and BSA by forming high molecular weight aggregates. Normal RBCs showed typical biconcave shape. MG modified RBCs showed twisted and elongated shape whereas the presence of ASP tends to protect RBC from twisting. Asp interacted with arginine residues of bovine serum albumin particularly ARG 194, ARG 198, and ARG 217 thereby stabilized the protein complex. We conclude that Asp has dual functions as a chemical chaperone to stabilize protein and as a dicarbonyl trapper, and thereby it can prevent the complications caused by glycation. PMID:26325019

  2. Dietary intake of advanced glycation end products did not affect endothelial function and inflammation in healthy adults in a randomized controlled trial

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When food is heated to high temperatures, the characteristic “browning” generates advanced glycation end products (AGEs) that result from the reaction of reducing sugars with proteins. AGEs have been implicated in an increased risk for cardiovascular disease, diabetes, and other adverse aging-relate...

  3. Advanced glycation end products promote differentiation of CD4(+) T helper cells toward pro-inflammatory response.

    PubMed

    Han, Xiao-qun; Gong, Zuo-jiong; Xu, San-qing; Li, Xun; Wang, Li-kun; Wu, Shi-min; Wu, Jian-hong; Yang, Hua-fen

    2014-02-01

    This study investigated the effect of advanced glycation end products (AGEs) on differentiation of naïve CD4(+) T cells and the role of the receptor of AGEs (RAGE) and peroxisome proliferator-activated receptors (PPARs) activity in the process in order to gain insight into the mechanism of immunological disorders in diabetes. AGEs were prepared by the reaction of bovine serum albumin (BSA) with glucose. Human naïve CD4(+) T cells, enriched from blood of healthy adult volunteers with negative selection assay, were cultured in vitro and treated with various agents including AGEs, BSA, high glucose, PGJ2 and PD68235 for indicated time. In short hairpin (sh) RNA knock-down experiment, naïve CD4(+) T cells were transduced with media containing shRNA-lentivirus generated from lentiviral packaging cell line, Lent-X(TM) 293 T cells. Surface and intracellular cytokine stainings were used for examination of CD4(+) T cell phenotypes, and real-time PCR and Western blotting for detection of transcription factor mRNA and protein expression, respectively. The suppressive function of regulatory T (Treg) cells was determined by a [(3)H]-thymidine incorporation assay. The results showed that AGEs induced higher pro-inflammatory Th1/Th17 cells differentiated from naïve CD4(+) T cells than the controls, whereas did not affect anti-inflammatory Treg cells. However, AGEs eliminated suppressive function of Treg cells. In addition, AGEs increased RAGE mRNA expression in naïve CD4(+) T cells, and RAGE knock-down by shRNA eliminated the effect of AGEs on the differentiation of CD4(+) T cells and the reduction of suppressive function of Treg cells. Furthermore, AGEs inhibited the mRNA expression of PPARγ, not PPARα PPARγ agonist, PGJ2, inhibited the effect of AGEs on naïve CD4(+) T cell differentiation and reversed the AGE-reduced suppressive function of Treg cells; on the other hand, PPARγ antagonist, PD68235, attenuated the blocking effect of RAGE shRNA on the role of AGEs. It

  4. Advanced glycation end products inhibit testosterone secretion by rat Leydig cells by inducing oxidative stress and endoplasmic reticulum stress.

    PubMed

    Zhao, Yun-Tao; Qi, Ya-Wei; Hu, Chuan-Yin; Chen, Shao-Hong; Liu, You

    2016-08-01

    Diabetes severely impairs male reproduction. The present study assessed the effects and mechanisms of action of advanced glycation end products (AGEs), which play an important role in the development of diabetes complications, on testosterone secretion by rat Leydig cells. Primary rat Leydig cells were cultured and treated with AGEs (25, 50, 100 and 200 µg/ml). Testosterone production induced by human chorionic gonadotropin (hCG) was determined by ELISA. The mRNA and protein expression levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase (3β-HSD), which are involved in testosterone biosynthesis, were measured by reverse transcription-quantitative PCR and western blot analyssi, respectively. Reactive oxygen species (ROS) production in Leydig cells was measured using the dichlorofluorescein diacetate (DCFH-DA) probe. The expression levels of endoplasmic reticulum stress-related proteins [C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78)] in the Leydig cells were measured by western blot analysis. We found that the AGEs markedly suppressed testosterone production by rat Leydig cells which was induced by hCG in a concentration-dependent manner compared with the control (P<0.01). The mRNA and protein expression levels of StAR, 3β-HSD and P450scc were downregulated by the AGEs in a dose-dependent manner compared with the control (P<0.01). The antioxidant agent, N-acetyl‑L‑cysteine (NAC), and the endoplasmic reticulum stress inhibitor, tauroursodeoxycholic acid (TUDCA), reversed the inhibitory effects of AGEs. In addition, the content of ROS in Leydig cells treated with AGEs increased significantly. The expression levels of CHOP and GRP78 were markedly upregulated by the AGEs in the Leydig cells. From these findings, it can be concluded that AGEs inhibit testosterone production by rat Leydig cells by inducing oxidative stress and

  5. Advanced Glycation End Products in Infant Formulas Do Not Contribute to Insulin Resistance Associated with Their Consumption

    PubMed Central

    Klenovics, Kristína Simon; Boor, Peter; Somoza, Veronika; Celec, Peter; Fogliano, Vincenzo; Šebeková, Katarína

    2013-01-01

    Introduction Infant formula-feeding is associated with reduced insulin sensitivity. In rodents and healthy humans, advanced glycation end product (AGE)-rich diets exert diabetogenic effects. In comparison with human breast-milk, infant formulas contain high amounts of AGEs. We assessed the role of AGEs in infant-formula-consumption-associated insulin resistance. Methods Total plasma levels of Nε-(carboxymethyl)lysine (CML), AGEs-associated fluorescence (λex = 370 nm/λem = 445 nm), soluble adhesion molecules, markers of micro- binflammation (hsCRP), oxidative stress (malondialdehyde, 8-isoprostanes) and leptinemia were determined, and correlated with insulin sensitivity in a cross-sectional study in 166 healthy term infants aged 3-to-14 months, subdivided according to feeding regimen (breast-milk- vs. infant formula-fed) and age (3-to-6-month-olds, 7-to-10-month-olds, and 11-to-14-month-old infants). Effects of the consumption of low- vs. high-CML-containing formulas were assessed. 36 infants aged 5.8±0.3 months were followed-up 7.5±0.3 months later. Results Cross-sectional study: 3-to-6-month-olds and 7-to-10-month-old formula-fed infants presented higher total plasma CML levels and AGEs-associated fluorescence (p<0.01, both), while only the 3-to-6-month-olds displayed lower insulin sensitivity (p<0.01) than their breast-milk-fed counterparts. 3-to-6-month-olds fed low-CML-containing formulas presented lower total plasma CML levels (p<0.01), but similar insulin sensitivity compared to those on high-CML-containing formulas. Markers of oxidative stress and inflammation, levels of leptin and adhesion molecules did not differ significantly between the groups. Follow-up study: at initial investigation, the breast-milk-consuming infants displayed lower total plasma CML levels (p<0.01) and AGEs-associated fluorescence (p<0.05), but higher insulin sensitivity (p<0.05) than the formulas-consuming infants. At follow-up, the groups did not differ significantly in

  6. PF-04494700, an Oral Inhibitor of Receptor For Advanced Glycation End Products (RAGE), in Alzheimer’s disease

    PubMed Central

    Sabbagh, Marwan N.; Agro, Albert; Bell, Joanne; Aisen, Paul S.; Schweizer, Edward; Galasko, Douglas

    2012-01-01

    Objective To evaluate the safety and tolerability of PF-04494700, an oral Inhibitor of receptor for advanced glycation end products (RAGE), in subjects with mild-to-moderate dementia of the Alzheimer’s type. Methods Subjects 50 years and older who met NINCDS-ADRDA criteria for AD with an MMSE score between 12–26 (inclusive) were randomized to 10-weeks of double-blind treatment with either a 10 mg “low dose” of PF-04494700 (after a 6-day loading dose of 30 mg/d to); or a 20 mg “high dose” of PF-04494700 (after a loading dose of 60 mg/d); or placebo. Safety measures included adverse events, laboratory tests, vital signs, and 12-lead ECG. Results 27 subjects received PF-04494700 30/10 mg (female, 63%; mean age, 74.6 years; mean MMSE, 21.1), 28 subjects received PF-04494700 60/20 mg (female, 57%; mean age, 76.6 years; mean MMSE, 21.6), and 12 subjects received placebo (female, 67%; mean age, 74.1 years; mean MMSE, 19.2). A higher proportion of subjects completed 10 weeks of double-blind treatment on both the “low dose” regimen of PF-04494700 (88.9%) and the “high dose” regimen (85.7%) than completed on placebo (66.7%). Discontinuation due to adverse events, and incidence of severe adverse events, respectively, were lower on the “low dose” regimen (7.4%,11.1%) and the “high dose” regimen (3.6%,10.7%) compared to placebo (25.0%,16.7%). There were no clinically meaningful differences in vital signs, laboratory test results, or mean ECG parameters in subjects treated with PF-04494700. PF-04494700 had no consistent effect on plasma levels of Aβ, inflammatory biomarkers, or secondary cognitive outcomes. Conclusions Ten weeks of treatment with PF-04494700 was safe and well-tolerated in subjects with mild-to-moderate AD, indicating the feasibility of a larger long-term efficacy trial. PMID:21192237

  7. Diastolic Dysfunction of Aging Is Independent of Myocardial Structure but Associated with Plasma Advanced Glycation End-Product Levels

    PubMed Central

    Campbell, Duncan J.; Somaratne, Jithendra B.; Jenkins, Alicia J.; Prior, David L.; Yii, Michael; Kenny, James F.; Newcomb, Andrew E.; Schalkwijk, Casper G.; Black, Mary Jane; Kelly, Darren J.

    2012-01-01

    Background Heart failure is associated with abnormalities of myocardial structure, and plasma levels of the advanced glycation end-product (AGE) Nε-(carboxymethyl)lysine (CML) correlate with the severity and prognosis of heart failure. Aging is associated with diastolic dysfunction and increased risk of heart failure, and we investigated the hypothesis that diastolic dysfunction of aging humans is associated with altered myocardial structure and plasma AGE levels. Methods We performed histological analysis of non-ischemic left ventricular myocardial biopsies and measured plasma levels of the AGEs CML and low molecular weight fluorophores (LMWFs) in 26 men undergoing coronary artery bypass graft surgery who had transthoracic echocardiography before surgery. None had previous cardiac surgery, myocardial infarction, atrial fibrillation, or heart failure. Results The patients were aged 43–78 years and increasing age was associated with echocardiographic indices of diastolic dysfunction, with higher mitral Doppler flow velocity A wave (r = 0.50, P = 0.02), lower mitral E/A wave ratio (r = 0.64, P = 0.001), longer mitral valve deceleration time (r = 0.42, P = 0.03) and lower early diastolic peak velocity of the mitral septal annulus, e’ (r = 0.55, P = 0.008). However, neither mitral E/A ratio nor mitral septal e’ was correlated with myocardial total, interstitial or perivascular fibrosis (picrosirius red), immunostaining for collagens I and III, CML, and receptor for AGEs (RAGE), cardiomyocyte width, capillary length density, diffusion radius or arteriolar dimensions. Plasma AGE levels were not associated with age. However, plasma CML levels were associated with E/A ratio (r = 0.44, P = 0.04) and e’ (r = 0.51, P = 0.02) and LMWF levels were associated with E/A ratio (r = 0.49, P = 0.02). Moreover, the mitral E/A ratio remained correlated with plasma LMWF levels in all patients (P = 0.04) and the mitral

  8. Association of the receptor for advanced glycation end-products (RAGE) gene polymorphisms in Malaysian patients with chronic kidney disease

    PubMed Central

    Wong, Foo Nian; Chua, Kek Heng; Kuppusamy, Umah Rani; Wong, Chew Ming; Lim, Soo Kun

    2016-01-01

    Background: Chronic kidney disease (CKD) is a condition associated with progressive loss of kidney function and kidney damage. The two common causes of CKD are diabetes mellitus and hypertension. Other causes of CKD also include polycystic kidney disease, obstructive uropathy and primary glomerulonephritis. The receptor for advanced glycation end-products (RAGE) is a multi-ligand cell surface receptor of the immunoglobulin superfamily and it has been associated with kidney disease in both non-diabetic and diabetic patients. Presently, data on the association between RAGE polymorphisms and CKD in the Malaysian population is limited, while numerous studies have reported associations of RAGE polymorphisms with diabetic complications in other populations. The present study aims to explore the possibility of using RAGE polymorphisms as candidate markers of CKD in Malaysian population by using association analysis. Methods: A total of 102 non-diabetic CKD patients, 204 diabetic CKD patients and 345 healthy controls were enrolled in the study. DNA isolated from blood samples were subjected to genotyping of RAGE G82S, −374T/A, −429T/C, 1704G/T and 2184A/G polymorphisms using real-time polymerase chain reaction (PCR). The 63-bp deletion, a polymorphism in the RAGE gene promoter, was genotyped using conventional PCR method and visualized using agarose gel electrophoresis. The collective frequencies of genotypes with at least one copy of the minor alleles of the four polymorphisms were compared between the non-diabetic CKD patients, diabetic CKD patients and healthy controls. Results: After adjustment of age, gender and ethnic groups in binary logistic regression analysis, the G82S CT + TT genotypes were associated with non-diabetic CKD patients when compared with diabetic CKD patients (p = 0.015, OR = 1.896, 95% CI = 1.132–3.176). After further adjustment of CKD comorbidities, the G82S CT + TT genotypes were still associated with non-diabetic CKD patients when compared

  9. Metformin reduces endothelial cell expression of both the receptor for advanced glycation end products and lectin-like oxidized receptor 1.

    PubMed

    Ouslimani, Nadjat; Mahrouf, Meriem; Peynet, Jacqueline; Bonnefont-Rousselot, Dominique; Cosson, Claudine; Legrand, Alain; Beaudeux, Jean-Louis

    2007-03-01

    Beyond its antihyperglycemic action, the antidiabetic oral drug metformin possesses antioxidant properties that may contribute to improve the cardiovascular deleterious effects of the diabetic disease. We explored whether metformin could modulate the redox-sensible expression of receptor for advanced glycation end products (RAGE) and lectin-like oxidized receptor 1 (LOX-1), 2 endothelial membrane receptors involved in the arterial endothelial dysfunction observed in diabetes. Bovine aortic endothelial cells, either unstimulated or activated by high levels of glucose (30 mmol/L) or advanced glycation end products, were incubated for 72 hours with metformin at therapeutically relevant concentrations (10(-5) to 5 x 10(-4) mol/L). The expressions of RAGE and LOX-1 were evaluated on cell extracts by Western blot analysis. Metformin was shown to reduce, in dose-dependent manner, such expression of the 2 receptors, both in stimulated (by either glucose or advanced glycation end products) and in unstimulated cells. The effect of metformin was associated with a decrease in intracellular reactive oxygen species as assessed using the 2',7'-dichlorodihydrofluorescein diacetate fluoroprobe. Taken together, our results suggest that the intracellular antioxidant properties of metformin may result in the inhibition of cell expression of both RAGE and LOX-1, possibly through a modulation of redox-sensible nuclear factors such as nuclear factor kappaB, that were shown to be involved in such receptor cell expression. PMID:17292717

  10. Advanced glycation end-products as markers of aging and longevity in the long-lived Ansell's mole-rat (Fukomys anselli).

    PubMed

    Dammann, Philip; Sell, David R; Begall, Sabine; Strauch, Christopher; Monnier, Vincent M

    2012-06-01

    Mole-rat of the genus Fukomys are mammals whose life span is strongly influenced by reproductive status with breeders far outliving nonbreeders. This raises the important question of whether increased longevity of the breeders is reflected in atypical expression of biochemical markers of aging. Here, we measured markers of glycation and advanced glycation end-products formed in insoluble skin collagen of Ansell's mole-rat Fukomys anselli as a function of age and breeding status. Glucosepane, pentosidine, and total advanced glycation end-product content significantly increased with age after correction for breeder status and sex. Unexpectedly, total advanced glycation end-products, glucosepane, and carboxymethyl-lysine (CML) were significantly higher in breeders versus nonbreeders suggesting that breeders have evolved powerful defenses against combined oxidant and carbonyl stress compared with nonbreeders. Most interestingly, when compared with other mammals, pentosidine formation rate was lower in mole-rat compared with other short-lived rodents confirming previous observations of an inverse relationship between longevity and pentosidine formation rates in skin collagen. PMID:22156473

  11. Advanced Glycation End-Products as Markers of Aging and Longevity in the Long-Lived Ansell’s Mole-Rat (Fukomys anselli)

    PubMed Central

    Dammann, Philip; Begall, Sabine; Strauch, Christopher; Monnier, Vincent M.

    2012-01-01

    Mole-rat of the genus Fukomys are mammals whose life span is strongly influenced by reproductive status with breeders far outliving nonbreeders. This raises the important question of whether increased longevity of the breeders is reflected in atypical expression of biochemical markers of aging. Here, we measured markers of glycation and advanced glycation end-products formed in insoluble skin collagen of Ansell’s mole-rat Fukomys anselli as a function of age and breeding status. Glucosepane, pentosidine, and total advanced glycation end-product content significantly increased with age after correction for breeder status and sex. Unexpectedly, total advanced glycation end-products, glucosepane, and carboxymethyl-lysine (CML) were significantly higher in breeders versus nonbreeders suggesting that breeders have evolved powerful defenses against combined oxidant and carbonyl stress compared with nonbreeders. Most interestingly, when compared with other mammals, pentosidine formation rate was lower in mole-rat compared with other short-lived rodents confirming previous observations of an inverse relationship between longevity and pentosidine formation rates in skin collagen. PMID:22156473

  12. Low Endogenous Secretory Receptor for Advanced Glycation End-Products Levels Are Associated With Inflammation and Carotid Atherosclerosis in Prediabetes.

    PubMed

    Di Pino, Antonino; Urbano, Francesca; Zagami, Rose Maria; Filippello, Agnese; Di Mauro, Stefania; Piro, Salvatore; Purrello, Francesco; Rabuazzo, Agata Maria

    2016-04-01

    Pre-diabetes is associated with advanced vascular damage. Our data shows that subjects with pre-diabetes exhibited low esRAGE plasma levels and gene expression, which are inversely related with markers of inflammation and atherosclerotic risk. PMID:26885882

  13. Effects of advanced glycation end products on ezrin-dependent functions in LLC-PK1 proximal tubule cells.

    PubMed

    Bach, Leon A; Gallicchio, Marisa A; McRobert, E Anne; Tikoo, Anjali; Cooper, Mark E

    2005-06-01

    We have recently shown that advanced glycation products (AGEs) bind to the ERM (ezrin, radixin, moesin) family of proteins. ERM proteins act as cross-linkers between cell membrane proteins and the actin cytoskeleton. They are also involved in signal transduction pathways. They therefore have a critical role in normal cell processes, including modulation of cell shape, adhesion, and motility. We postulate that AGEs may contribute to diabetic complications by disrupting ERM function. In support of this hypothesis, AGEs inhibit ezrin-dependent tubulogenesis of proximal tubule cells. Phosphorylation is an important activating mechanism for ERM proteins, and AGEs inhibit ezrin phosphorylation mediated by the epidermal growth factor receptor. PMID:16037284

  14. The receptor for advanced glycation end products promotes bacterial growth at distant body sites in Staphylococcus aureus skin infection.

    PubMed

    Achouiti, Ahmed; Van't Veer, Cornelis; de Vos, Alex F; van der Poll, Tom

    2015-09-01

    The receptor for advanced glycation endproducts (RAGE) has been implicated in the regulation of skin inflammation. We here sought to study the role of RAGE in host defense during skin infection caused by Staphylococcus (S.) aureus, the most common pathogen in this condition. Wild-type (Wt) and RAGE deficient (rage(-/-)) mice were infected subcutaneously with S. aureus and bacterial loads and local inflammation were quantified at regular intervals up to 8 days after infection. While bacterial burdens were similar in both mouse strains at the primary site of infection, rage(-/-) mice had lower bacterial counts in lungs and liver. Skin cytokine and chemokine levels did not differ between groups. In accordance with the skin model, direct intravenous infection with S. aureus was associated with lower bacterial loads in lungs and liver of rage(-/-) mice. Together these data suggest that RAGE does not impact local host defense during S. aureus skin infection, but facilitates bacterial growth at distant body sites. PMID:26086798

  15. Age- and diabetes-related nonenzymatic crosslinks in collagen fibrils: candidate amino acids involved in Advanced Glycation End-products.

    PubMed

    Gautieri, Alfonso; Redaelli, Alberto; Buehler, Markus J; Vesentini, Simone

    2014-02-01

    Ageing and diabetes share a common deleterious phenomenon, the formation of Advanced Glycation Endproducts (AGEs), which accumulate predominantly in collagen due to its low turnover. Though the general picture of glycation has been identified, the detailed knowledge of which collagen amino acids are involved in AGEs is still missing. In this work we use an atomistic model of a collagen fibril to pinpoint, for the first time, the precise location of amino acids involved in the most relevant AGE, glucosepane. The results show that there are 14 specific lysine-arginine pairs that, due to their relative position and configuration, are likely to form glucosepane. We find that several residues involved in AGE crosslinks are within key collagen domains, such as binding sites for integrins, proteoglycans and collagenase, hence providing molecular-level explanations of previous experimental results showing decreased collagen affinity for key molecules. Altogether, these findings reveal the molecular mechanism by which glycation affects the biological properties of collagen tissues, which in turn contribute to age- and diabetes-related pathological states. PMID:24060753

  16. In vivo imaging of advanced glycation end products (AGEs) of albumin: first observations of significantly reduced clearance and liver deposition properties in mice.

    PubMed

    Tsutsui, Ayumi; Ogura, Akihiro; Tahara, Tsuyoshi; Nozaki, Satoshi; Urano, Sayaka; Hara, Mitsuko; Kojima, Soichi; Kurbangalieva, Almira; Onoe, Hirotaka; Watanabe, Yasuyoshi; Taniguchi, Naoyuki; Tanaka, Katsunori

    2016-06-15

    Advanced glycation end products (AGEs) are associated with various diseases, especially during aging and the development of diabetes and uremia. To better understand these biological processes, investigation of the in vivo kinetics of AGEs, i.e., analysis of trafficking and clearance properties, was carried out by molecular imaging. Following the preparation of Cy7.5-labeled AGE-albumin and intravenous injection in BALB/cA-nu/nu mice, noninvasive fluorescence kinetics analysis was performed. In vivo imaging and fluorescence microscopy analysis revealed that non-enzymatic AGEs were smoothly captured by scavenger cells in the liver, i.e., Kupffer and other sinusoidal cells, but were unable to be properly cleared from the body. Overall, these results highlight an important link between AGEs and various disorders associated with them, which may serve as a platform for future research to better understand the processes and mechanisms of these disorders. PMID:26932508

  17. Serum carboxymethyllysine, an advanced glycation end product, and age-related macular degeneration: the Age, Gene/Environment Susceptibility-Reykjavik Study.

    PubMed

    Semba, Richard D; Cotch, Mary Frances; Gudnason, Vilmundur; Eiríksdottir, Gudny; Harris, Tamara B; Sun, Kai; Klein, Ronald; Jonasson, Fridbert; Ferrucci, Luigi; Schaumberg, Debra A

    2014-04-01

    IMPORTANCE Advanced glycation end products have been implicated in the pathogenesis of age-related macular degeneration (AMD). OBJECTIVE To investigate the relationship between serum carboxymethyllysine (CML), a major circulating advanced glycation end product, and AMD in older adults. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study of a population-based sample of 4907 older adults (aged ≥66 years) in the Age, Gene/Environment Susceptibility-Reykjavik Study in Iceland. EXPOSURES Serum CML and risk factors for AMD. MAIN OUTCOMES AND MEASURES Early or late AMD, assessed through fundus images taken through dilated pupils using a 45° digital camera and grading for drusen size, type, area, increased retinal pigment, retinal pigment epithelial depigmentation, neovascular lesions, and geographic atrophy using the modified Wisconsin Age-Related Maculopathy Grading System. RESULTS Of the 4907 participants, 1025 (20.9%) had early AMD and 276 (5.6%) had late AMD. Mean (SD) serum CML concentrations among adults with no AMD, early AMD, and late AMD (exudative AMD and pure geographic atrophy) were 618.8 (195.5), 634.2 (206.4), and 638.4 (192.0) ng/mL, respectively (to convert to micromoles per liter, multiply by 0.00489; P = .07). Log serum CML (per 1-SD increase) was not associated with any AMD (early and late AMD) (odds ratio = 0.97; 95% CI, 0.90-1.04; P = .44) or with late AMD (odds ratio = 0.94; 95% CI, 0.82-1.08; P = .36) in respective multivariable logistic regression models adjusting for age, sex, body mass index, smoking, and renal function. CONCLUSIONS AND RELEVANCE Higher serum CML concentration had no significant cross-sectional association with prevalent AMD in this large population-based cohort of older adults in Iceland. PMID:24481410

  18. Increased Expression of Tissue Factor and Receptor for Advanced Glycation End Products in Peripheral Blood Mononuclear Cells of Patients With Type 2 Diabetes Mellitus with Vascular Complications

    PubMed Central

    Buchs, A. E.; Kornberg, A.; Zahavi, M.; Aharoni, D.; Zarfati, C.; Rapoport, M. J.

    2004-01-01

    The aim of the study was to determine the correlation between the expression of tissue factor (TF) and the receptor for advanced glycation end products (RAGEs) and vascular complications in patients with longstanding uncontrolled type 2 diabetes (T2D). TF and RAGE mRNAs as well as TF antigen and activity were investigated in 21 T2D patients with and without vascular complications. mRNA expression was assessed by reverse transcriptase–polymerase chain reaction (RT-PCR) in nonstimulated and advanced glycation end product (AGE) albumin–stimulated peripheral blood mononuclear cells (PBMCs). TF antigen expression was determined by enzyme-linked immunosorbent assay (ELISA) and TF activity by a modified prothrombin time assay. Basal RAGE mRNA expression was 0.2 ± 0.06 in patients with complications and 0.05 ± 0.06 patients without complications (P = .004). Stimulation did not cause any further increase in either group. TF mRNA was 0.58 ± 0.29 in patients with complications and 0.21 ± 0.18 in patients without complications (P = .003). Stimulation resulted in a nonsignificant increase in both groups. Basal TF activity (U/106 PBMCs) was 18.4 ± 13.2 in patients with complications and 6.96 ± 5.2 in patients without complications (P = .003). It increased 3-fold in both groups after stimulation (P = .001). TF antigen (pg/106 PBMCs) was 33.7 ± 28.6 in patients with complications, 10.4 ± 7.8 in patients without complications (P = .02). Stimulation tripled TF antigen in both groups of patients (P = .001). The RAGE/TF axis is up-regulated inT2Dpatients with vascular complications as compared to patients without complications. This suggests a role for this axis in the pathogenesis of vascular complications in T2D. PMID:15203887

  19. Inflammatory markers associated with osteoarthritis after destabilization surgery in young mice with and without Receptor for Advanced Glycation End-products (RAGE)

    PubMed Central

    Larkin, D. Justin; Kartchner, Jeffrey Z.; Doxey, Alexander S.; Hollis, Weston R.; Rees, Jeffrey L.; Wilhelm, Spencer K.; Draper, Christian S.; Peterson, Danielle M.; Jackson, Gregory G.; Ingersoll, Chelsey; Haynie, S. Scott; Chavez, Elizabeth; Reynolds, Paul R.; Kooyman, David L.

    2013-01-01

    HtrA1, Ddr-2, and Mmp-13 are reliable biomarkers for osteoarthritis (OA), yet the exact mechanism for the upregulation of HtrA-1 is unknown. Some have shown that chondrocyte hypertrophy is associated with early indicators of inflammation including TGF-β and the Receptor for Advanced Glycation End-products (RAGE). To examine the correlation of inflammation with the expression of biomarkers in OA, we performed right knee destabilization surgery on 4-week-old-wild type and RAGE knock-out (KO) mice. We assayed for HtrA-1, TGF-β1, Mmp-13, and Ddr-2 in articular cartilage at 3, 7, 14, and 28 days post-surgery by immunohistochemistry on left and right knee joints. RAGE KO and wild type mice both showed staining for key OA biomarkers. However, RAGE KO mice were significantly protected against OA compared to controls. We observed a difference in the total number of chondrocytes and percentage of chondrocytes staining positive for OA biomarkers between RAGE KO and control mice. The percentage of cells staining for OA biomarkers correlated with severity of cartilage degradation. Our results indicate that the absence of RAGE did protect against the development of advanced OA. We conclude that HtrA-1 plays a role in lowering TGF-β1 expression in the process of making articular cartilage vulnerable to damage associated with OA progression. PMID:23755017

  20. Receptor for advanced glycation end-products regulates lung fluid balance via protein kinase C-gp91(phox) signaling to epithelial sodium channels.

    PubMed

    Downs, Charles A; Kreiner, Lisa H; Johnson, Nicholle M; Brown, Lou Ann; Helms, My N

    2015-01-01

    The receptor for advanced glycation end-products (RAGE), a multiligand member of the Ig family, may play a crucial role in the regulation of lung fluid balance. We quantified soluble RAGE (sRAGE), a decoy isoform, and advanced glycation end-products (AGEs) from the bronchoalveolar lavage fluid of smokers and nonsmokers, and tested the hypothesis that AGEs regulate lung fluid balance through protein kinase C (PKC)-gp91(phox) signaling to the epithelial sodium channel (ENaC). Human bronchoalveolar lavage samples from smokers showed increased AGEs (9.02 ± 3.03 μg versus 2.48 ± 0.53 μg), lower sRAGE (1,205 ± 292 pg/ml versus 1,910 ± 263 pg/ml), and lower volume(s) of epithelial lining fluid (97 ± 14 ml versus 133 ± 17 ml). sRAGE levels did not predict ELF volumes in nonsmokers; however, in smokers, higher volumes of ELF were predicted with higher levels of sRAGE. Single-channel patch clamp analysis of rat alveolar epithelial type 1 cells showed that AGEs increased ENaC activity measured as the product of the number of channels (N) and the open probability (Po) (NPo) from 0.19 ± 0.08 to 0.83 ± 0.22 (P = 0.017) and the subsequent addition of 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-N-oxyl decreased ENaC NPo to 0.15 ± 0.07 (P = 0.01). In type 2 cells, human AGEs increased ENaC NPo from 0.12 ± 0.05 to 0.53 ± 0.16 (P = 0.025) and the addition of 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-N-oxyl decreased ENaC NPo to 0.10 ± 0.03 (P = 0.013). Using molecular and biochemical techniques, we observed that inhibition of RAGE and PKC activity attenuated AGE-induced activation of ENaC. AGEs induced phosphorylation of p47(phox) and increased gp91(phox)-dependent reactive oxygen species production, a response that was abrogated with RAGE or PKC inhibition. Finally, tracheal instillation of AGEs promoted clearance of lung fluid, whereas concomitant inhibition of RAGE, PKC, and gp91(phox) abrogated the response. PMID:24978055

  1. Deletion of receptor for advanced glycation end products exacerbates lymphoproliferative syndrome and lupus nephritis in B6-MRL Fas lpr/j mice.

    PubMed

    Goury, Antoine; Meghraoui-Kheddar, Aïda; Belmokhtar, Karim; Vuiblet, Vincent; Ortillon, Jeremy; Jaisson, Stéphane; Devy, Jerôme; Le Naour, Richard; Tabary, Thierry; Cohen, Jacques H M; Schmidt, Ann-Marie; Rieu, Philippe; Touré, Fatouma

    2015-04-15

    The receptor for advanced glycation end products (RAGE) is a pattern recognition receptor that interacts with advanced glycation end products, but also with C3a, CpG DNA oligonucleotides, and alarmin molecules such as HMGB1 to initiate a proinflammatory reaction. Systemic lupus erythematosus is an autoimmune disorder associated with the accumulation of RAGE ligands. We generated mice invalidated for RAGE in the lupus-prone B6-MRL Fas lpr/j background to determine the role of RAGE in the pathogenesis of systemic lupus erythematosus. We compared the phenotype of these mice with that of their wild-type and B6-MRL Fas lpr/j littermates. Lymphoproliferative syndrome, production of anti-dsDNA Abs, lupus nephritis, and accumulation of CD3(+)B220(+)CD4(-)CD8(-) autoreactive T cells (in the peripheral blood and the spleen) were significantly increased in B6-MRL Fas lpr/j RAGE(-/-) mice compared with B6-MRL Fas lpr/j mice (respectively p < 0.005, p < 0.05, p < 0.001, and p < 0.001). A large proportion of autoreactive T cells from B6-MRL Fas lpr/j mice expressed RAGE at their surface. Time course studies of annexin V expression revealed that autoreactive T cells in the spleen of B6-MRL Fas lpr/j-RAGE(-/-) mice exhibited a delay in apoptosis and expressed significantly less activated caspase 3 (39.5 ± 4.3%) than T cells in B6-MRL Fas lpr/j mice (65.5 ± 5.2%) or wild-type mice (75.3 ± 2.64%) (p = 0.02). We conclude that the deletion of RAGE in B6-MRL Fas lpr/j mice promotes the accumulation of autoreactive CD3(+)B220(+)CD4(-)CD8(-) T cells, therefore exacerbating lymphoproliferative syndrome, autoimmunity, and organ injury. This suggests that RAGE rescues the apoptosis of T lymphocytes when the death receptor Fas/CD95 is dysfunctional. PMID:25762779

  2. Early expression of the receptor for advanced glycation end products in a toxic model produced by 6-hydroxydopamine in the rat striatum.

    PubMed

    Serratos, Iris N; Castellanos, Pilar; Pastor, Nina; Millán-Pacheco, César; Colín-González, Ana Laura; Rembao, Daniel; Pérez-Montfort, Ruy; Cabrera, Nallely; Sánchez-García, Aurora; Gómez, Isabel; Rangel-López, Edgar; Santamaria, Abel

    2016-04-01

    The receptor for advanced glycation end products (RAGE) is commonly involved in different neurodegenerative and inflammatory disorders. The cellular signaling associated to RAGE activation may occur upon binding to different ligands. In this study we investigated whether the toxic model produced by 6-hydroxydopamine (6-OHDA) in rats comprises early noxious responses related to RAGE-mediated signaling cascades. In order to explore a possible interaction between 6-OHDA and RAGE, affinity parameters of RAGE with 6-OHDA were estimated by different means. The possible binding sites of 6-OHDA with the VC1 homodimer for both rat and human RAGE were also modeled. Our results show that the striatal infusion of 6-OHDA recruits RAGE upregulation, as evidenced by an early expression of the receptor. 6-OHDA was also found to bind the VC1 homodimer, although its affinity was moderate when compared to other ligands. This work contributes to the understanding of the role of RAGE activation for 6-OHDA-induced neurotoxicity. PMID:26902637

  3. Advanced Glycation End-Products and Their Receptors: Related Pathologies, Recent Therapeutic Strategies, and a Potential Model for Future Neurodegeneration Studies.

    PubMed

    Pinkas, Adi; Aschner, Michael

    2016-05-16

    Advanced glycation end products (AGEs) are the result of a nonenzymatic reaction between sugars and proteins, lipids, or nucleic acids. AGEs are both consumed and endogenously formed; their accumulation is accelerated under hyperglycemic and oxidative stress conditions, and they are associated with the onset and complication of many diseases, such as cardiovascular diseases, diabetes, and Alzheimer's disease. AGEs exert their deleterious effects by either accumulating in the circulation and tissues or by receptor-mediated signal transduction. Several receptors bind AGEs: some are specific and contribute to clearance of AGEs, whereas others, like the RAGE receptor, are nonspecific, associated with inflammation and oxidative stress, and considered to be mediators of the aforementioned AGE-related diseases. Although several anti-AGE compounds have been studied, understanding the underlying mechanisms of RAGE and targeting it as a therapeutic strategy is becoming increasingly desirable. For achieving these goals efficiently and expeditiously, the C. elegans model has been suggested. This model is already used for studying several human diseases and, by expressing RAGE, could also be used to study RAGE-related pathways and pathologies to facilitate the development of novel therapeutic strategies. PMID:27054356

  4. High dietary advanced glycation end products are associated with poorer spatial learning and accelerated Aβ deposition in an Alzheimer mouse model.

    PubMed

    Lubitz, Irit; Ricny, Jan; Atrakchi-Baranes, Dana; Shemesh, Chen; Kravitz, Efrat; Liraz-Zaltsman, Sigal; Maksin-Matveev, Anna; Cooper, Itzik; Leibowitz, Avshalom; Uribarri, Jaime; Schmeidler, James; Cai, Weijing; Kristofikova, Zdena; Ripova, Daniela; LeRoith, Derek; Schnaider-Beeri, Michal

    2016-04-01

    There is growing evidence of the involvement of advanced glycation end products (AGEs) in the pathogenesis of neurodegenerative processes including Alzheimer's disease (AD) and their function as a seed for the aggregation of Aβ, a hallmark feature of AD. AGEs are formed endogenously and exogenously during heating and irradiation of foods. We here examined the effect of a diet high in AGEs in the context of an irradiated diet on memory, insoluble Aβ42 , AGEs levels in hippocampus, on expression of the receptor for AGEs (RAGE), and on oxidative stress in the vasculature. We found that AD-like model mice on high-AGE diet due to irradiation had significantly poorer memory, higher hippocampal levels of insoluble Aβ42 and AGEs as well as higher levels of oxidative stress on vascular walls, compared to littermates fed an isocaloric diet. These differences were not due to weight gain. The data were further supported by the overexpression of RAGE, which binds to Aβ42 and regulates its transport across the blood-brain barrier, suggesting a mediating pathway. Because exposure to AGEs can be diminished, these insights provide an important simple noninvasive potential therapeutic strategy for alleviating a major lifestyle-linked disease epidemic. PMID:26781037

  5. Effect of Amaranthus on Advanced Glycation End-Products Induced Cytotoxicity and Proinflammatory Cytokine Gene Expression in SH-SY5Y Cells.

    PubMed

    Amornrit, Warisa; Santiyanont, Rachana

    2015-01-01

    Amaranthus plants, or spinach, are used extensively as a vegetable and are known to possess medicinal properties. Neuroinflammation and oxidative stress play a major role in the pathogenesis of many neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Advanced glycation end-products (AGEs) cause cell toxicity in the human neuronal cell line, SH-SY5Y, through an increase in oxidative stress, as shown by reducing cell viability and increasing cell toxicity in a dose-dependent manner. We found that preincubation of SH-SY5Y cells with either petroleum ether, dichloromethane or methanol extracts of A. lividus and A. tricolor dose-dependently attenuated the neuron toxicity caused by AGEs treatment. Moreover, the results showed that A. lividus and A. tricolor extracts significantly downregulated the gene expression of the pro-inflammatory cytokines, TNF-α, IL-1 and IL-6 genes in AGEs-induced cells. We concluded that A. lividus and A. tricolor extracts not only have a neuroprotective effect against AGEs toxicity, but also have anti-inflammatory activity by reducing pro-inflammatory cytokine gene expression. This suggests that Amaranthus may be useful for treating chronic inflammation associated with neurodegenerative disorders. PMID:26393562

  6. Advanced Glycation End-Products Induce Connective Tissue Growth Factor-Mediated Renal Fibrosis Predominantly through Transforming Growth Factor β-Independent Pathway

    PubMed Central

    Zhou, Guihua; Li, Cai; Cai, Lu

    2004-01-01

    Advanced glycation end-products (AGEs) play a critical role in diabetic nephropathy by stimulating extracellular matrix (ECM) synthesis. Connective tissue growth factor (CTGF) is a potent inducer of ECM synthesis and increases in the diabetic kidneys. To determine the critical role of CTGF in AGE-induced ECM accumulation leading to diabetic nephropathy, rats were given AGEs by intravenous injection for 6 weeks. AGE treatment induced a significant renal ECM accumulation, as shown by increases in periodic acid-Schiff-positive materials, fibronectin, and type IV collagen (Col IV) accumulation in glomeruli, and a mild renal dysfunction, as shown by increases in urinary volume and protein content. AGE treatment also caused significant increases in renal CTGF and transforming growth factor (TGF)-β1 mRNA and protein expression. Direct exposure of rat mesangial cells to AGEs in vitro significantly induced increases in fibronectin and Col IV production, which could be completely prevented by pretreatment with anti-CTGF antibody. AGE treatment also significantly increased both TGF-β1 and CTGF mRNA expression; however, inhibition of TGF-β1 mRNA expression by shRNA or neutralization of TGF-β1 protein by anti-TGF-β1 antibody did not significantly prevent AGE-increased expression of CTGF mRNA and protein. These results suggest that AGE-induced CTGF expression, predominantly through a TGF-β1-independent pathway, plays a critical role in renal ECM accumulation leading to diabetic nephropathy. PMID:15579446

  7. Guarana (Paullinia cupana Mart.) prevents β-amyloid aggregation, generation of advanced glycation-end products (AGEs), and acrolein-induced cytotoxicity on human neuronal-like cells.

    PubMed

    Bittencourt, Leonardo da Silva; Zeidán-Chuliá, Fares; Yatsu, Francini Kiyono Jorge; Schnorr, Carlos Eduardo; Moresco, Karla Suzana; Kolling, Eduardo Antônio; Gelain, Daniel Pens; Bassani, Valquiria Linck; Moreira, José Cláudio Fonseca

    2014-11-01

    Advanced glycation end-products (AGEs) are considered potent molecules capable of promoting neuronal cell death and participating in the development of neurodegenerative disorders such as Alzheimer's disease (AD). Previous studies have shown that AGEs exacerbate β-amyloid (Aβ) aggregation and AGE-related cross-links are also detected in senile plaques. Acrolein (ACR) is an α, β-unsaturated aldehyde found in the environment and thermally processed foods, which can additionally be generated through endogenous metabolism. The role of ACR in AD is widely accepted in the literature. Guarana (Paullinia cupana Mart.) is popularly consumed by the population in Brazil, mainly for its stimulant activity. In the present study, we showed that guarana (10, 100, and 1000 µg/mL) is able to prevent protein glycation, β-amyloid aggregation, in vitro methylglyoxal, glyoxal, and ACR (20 μM)-induced toxicity on neuronal-like cells (SH-SY5Y). Since these are considered typical AD pathological hallmarks, we propose that guarana may deserve further research as a potential therapeutic agent in such a neurodegenerative disease. PMID:24840232

  8. DNA aptamer raised against advanced glycation end products (AGEs) improves glycemic control and decreases adipocyte size in fructose-fed rats by suppressing AGE-RAGE axis.

    PubMed

    Ojima, A; Matsui, T; Nakamura, N; Higashimoto, Y; Ueda, S; Fukami, K; Okuda, S; Yamagishi, S

    2015-04-01

    Advanced glycation end products (AGEs) decrease adiponectin expression and suppress insulin signaling in cultured adipocytes through the interaction with a receptor for AGEs (RAGE) via oxidative stress generation. We have recently found that high-affinity DNA aptamer directed against AGE (AGE-aptamer) prevents the progression of experimental diabetic nephropathy by blocking the harmful actions of AGEs in the kidney. This study examined the effects of AGE-aptamer on adipocyte remodeling, AGE-RAGE-oxidative stress axis, and adiponectin expression in fructose-fed rats. Although AGE-aptamer treatment by an osmotic mini pump for 8 weeks did not affect serum insulin levels, it significantly decreased average fasting blood glucose and had a tendency to inhibit body weight gain in fructose-fed rats. Furthermore, AGE-aptamer significantly suppressed the increase in adipocyte size and prevented the elevation in AGEs, RAGE, and an oxidative stress marker, 8-hydroxydeoxyguanosine (8-OHdG), levels in adipose tissues of fructose-fed rats at 14-week-old, while it restored the decrease in adiponectin mRNA levels. Our present study suggests that AGE-aptamer could improve glycemic control and prevent adipocyte remodeling in fructose-fed rats partly by suppressing the AGE-RAGE-mediated oxidative stress generation. AGE-aptamer might be a novel therapeutic strategy for fructose-induced metabolic derangements. PMID:25105541

  9. Plasma Proteins Modified by Advanced Glycation End Products (AGEs) Reveal Site-specific Susceptibilities to Glycemic Control in Patients with Type 2 Diabetes.

    PubMed

    Greifenhagen, Uta; Frolov, Andrej; Blüher, Matthias; Hoffmann, Ralf

    2016-04-29

    Protein glycation refers to the reversible reaction between aldoses (or ketoses) and amino groups yielding relatively stable Amadori (or Heyns) products. Consecutive oxidative cleavage reactions of these products or the reaction of amino groups with other reactive substances (e.g. α-dicarbonyls) yield advanced glycation end products (AGEs) that can alter the structures and functions of proteins. AGEs have been identified in all organisms, and their contents appear to rise with some diseases, such as diabetes and obesity. Here, we report a pilot study using highly sensitive and specific proteomics approach to identify and quantify AGE modification sites in plasma proteins by reversed phase HPLC mass spectrometry in tryptic plasma digests. In total, 19 AGE modification sites corresponding to 11 proteins were identified in patients with type 2 diabetes mellitus under poor glycemic control. The modification degrees of 15 modification sites did not differ among cohorts of normoglycemic lean or obese and type 2 diabetes mellitus patients under good and poor glycemic control. The contents of two amide-AGEs in human serum albumin and apolipoprotein A-II were significantly higher in patients with poor glycemic control, although the plasma levels of both proteins were similar among all plasma samples. These two modification sites might be useful to predict long term, AGE-related complications in diabetic patients, such as impaired vision, increased arterial stiffness, or decreased kidney function. PMID:26933035

  10. Inhibitory effect of quercetin in the formation of advance glycation end products of human serum albumin: An in vitro and molecular interaction study.

    PubMed

    Alam, Md Maroof; Ahmad, Irshad; Naseem, Imrana

    2015-08-01

    Non-enzymatic glycation entails the reaction between the carbonyl group of a sugar with the amino group of a protein giving rise to Schiff base and Amadori products. The formation of advanced glycation end products (AGEs) leads to the generation of free radicals, which play an important role in the pathophysiology of ageing and diabetes. Bioavailable dietary antioxidants like quercetin (QC) are thought to inhibit AGEs formation. This study was aimed to investigate the effect of quercetin on AGE formation and features the glycation of human serum albumin (HSA) and its characterization by various spectroscopic techniques. The effect of quercetin, against the formation of AGEs was studied using a glycated human serum albumin product, haemoglobin-δ-gluconolactone, and aminoguanidine. The results were then corroborated with estimation of protein oxidation, lipid peroxidation and comet assay. On the basis of the experimental data, computational docking studies were then performed to understand the location of the site of quercetin binding and its best bound conformation with respect to human serum albumin. Through this study we have demonstrated the mechanism of formation of AGE and its inhibition by quercetin. We have also suggested that the supplementation with dietary antioxidants like quercetin might protect against free radical toxicity. PMID:25982953

  11. Receptor-mediated endothelial cell dysfunction in diabetic vasculopathy. Soluble receptor for advanced glycation end products blocks hyperpermeability in diabetic rats.

    PubMed

    Wautier, J L; Zoukourian, C; Chappey, O; Wautier, M P; Guillausseau, P J; Cao, R; Hori, O; Stern, D; Schmidt, A M

    1996-01-01

    Dysfunctional endothelium is associated with and, likely, predates clinical complications of diabetes mellitus, by promoting increased vascular permeability and thrombogenicity. Irreversible advanced glycation end products (AGEs), resulting from nonenzymatic glycation and oxidation of proteins or lipids, are found in plasma, vessel wall, and tissues and have been linked to the development of diabetic complications. The principal means through which AGEs exert their cellular effects is via specific cellular receptors, one of which, receptor for AGE (RAGE), is expressed by endothelium. We report that blockade of RAGE inhibits AGE-induced impairment of endothelial barrier function, and reverse, in large part, the early vascular hyperpermeability observed in diabetic rats. Inhibition of AGE- and diabetes-mediated hyperpermeability by antioxidants, both in vitro and in vivo, suggested the central role of AGE-RAGE-induced oxidant stress in the development of hyperpermeability. Taken together, these data support the concept that ligation of AGEs by endothelial RAGE induces cellular dysfunction, at least in part by an oxidant-sensitive mechanism, contributing to vascular hyperpermeability in diabetes, and that RAGE is central to this pathologic process. PMID:8550841

  12. Telmisartan inhibits advanced glycation end products (AGEs)-elicited endothelial cell injury by suppressing AGE receptor (RAGE) expression via peroxisome proliferator-activated receptor-gammaactivation.

    PubMed

    Yamagishi, Sho-ichi; Matsui, Takanori; Nakamura, Kazuo; Takeuchi, Masayoshi; Inoue, Hiroyoshi

    2008-01-01

    Advanced glycation end products (AGEs)-their receptor (RAGE) axis plays a central role in the pathogenesis of diabetic microangiopathy. Since the pathophysiological crosstalk between the AGEs-RAGE system and angiotensin II has also been associated with diabetic microangiopathy, we examined here whether and how telmisartan, a unique angiotensin II type 1 receptor blocker (ARB) with peroxisome proliferator-activated receptor-gamma (PPAR-gamma)-modulating activity, could inhibit the AGEs-elicited endothelial cell injury by suppressing RAGE expression in vitro. Telmisartan suppressed RAGE expression at both mRNA and protein levels in human cultured microvascular endothelial cells (ECs), which were prevented by GW9662, an inhibitor of PPAR-gamma. Further, telmisartan was found to inhibit up-regulation of mRNA levels for monocyte chemoattractant protein-1, intercellular adhesion molecule-1 and vascular endothelial growth factor in AGEs-exposed ECs. These results suggest that telmisartan inhibits the AGEs-elicited EC injury by down-regulating RAGE expression via PPAR-gamma activation. Our present study provides a unique beneficial aspect of telmisartan. Specifically, it could work as an anti-inflammatory agent against AGEs via PPAR-gamma activation and may play a protective role against diabetic microangiopathy. PMID:18855759

  13. Solution structure of the variable-type domain of the receptor for advanced glycation end products: new insight into AGE-RAGE interaction.

    PubMed

    Matsumoto, Shigeyuki; Yoshida, Takuya; Murata, Hiroko; Harada, Shusaku; Fujita, Naoko; Nakamura, Shota; Yamamoto, Yasuhiko; Watanabe, Takuo; Yonekura, Hideto; Yamamoto, Hiroshi; Ohkubo, Tadayasu; Kobayashi, Yuji

    2008-11-25

    Diabetes is defined by chronic hyperglycemia due to deficiency in insulin action. It has been found that the amount of advanced glycation end products (AGE) from the Maillard reaction between proteins and sugar molecules increases in blood of diabetic patients and furthermore that AGE binding to their cell surface receptor (RAGE) triggers both macrovascular and microvascular impairments to cause diabetic complications. Due to the clinical significance of the vascular complications, RAGE is currently a focus as an attractive target for drug discovery of candidates which interfere with AGE-RAGE binding to prevent the subsequent intracellular signaling related to pathogenical effects. Here, we determined the three-dimensional structure of the recombinant AGE-binding domain by using multidimensional heteronuclear NMR spectroscopy and showed that the domain assumes a structure similar to those of other immunoglobulin V-type domains. The site-directed mutagenesis studies identified the basic amino acids which play a key role in the AGE binding activities. Our results obtained from this study provide new insight into AGE-RAGE interaction. PMID:19032093

  14. Involvement of Na{sup +}/H{sup +} exchanger 1 in advanced glycation end products-induced proliferation of vascular smooth muscle cell

    SciTech Connect

    Wu Shujin; Song Tao; Zhou Shouhong; Liu Yuhui; Chen Gengrong; Huang Ningjiang; Liu Liying

    2008-10-24

    In this present study, we examined the role of Na{sup +}/H{sup +} exchanger 1 (NHE1) in the cultured rat vascular smooth muscle cell (VSMC) proliferation induced by advanced glycation end products (AGEs). AGEs significantly increased the [{sup 3}H] thymidine incorporation of VSMC. Cariporide, an NHE1 inhibitor, dose-dependently attenuated the AGEs-induced increase in cell DNA synthesis. Thus the effect of AGEs on NHE1 activity was next examined. The cariporide-dependent intracellular pH (pH{sub i}) was significantly increased after 24 h exposure to AGEs (10 {mu}g/ml). The direct AGEs-induced NHE1 activation was measured by the Na{sup +}-dependent intracellular pH recovery from intracellular acidosis. AGEs can increase the NHE1 activity in a time- and concentration-dependent manner. Inhibition of either the receptor for AGEs (RAGE) by anti-RAGE or mitogen-activated protein kinases (MAPK) by PD98059 reversed the effect of AGEs on NHE1 activity. Reverse transcription (RT)-PCR analysis revealed that AGEs dose-dependently increased NHE1 mRNA at 24 h. These findings demonstrate NHE1 is required for in AGEs-induced proliferation of VSMC, and AGEs increase NHE1 activity via the MAPK pathway.

  15. Advanced glycation end products induce endothelial-to-mesenchymal transition via downregulating Sirt 1 and upregulating TGF-β in human endothelial cells.

    PubMed

    He, Wei; Zhang, Jian; Gan, Tian-yi; Xu, Guo-jun; Tang, Bao-peng

    2015-01-01

    In the present study, we examined the advanced glycation end products- (AGEs-) induced endothelial-to-mesenchymal transition (EndMT) in human umbilical vein endothelial cells (HUVECs). Results demonstrated that AGE-BSAs significantly reduced the cluster of differentiation 31 (CD 31) expression, whereas they promoted the expression of fibroblast-specific protein-1 (FSP-1), α-smooth muscle antibody (α-SMA), and collagen I at both mRNA and protein levels in HUVECs. And the AGE-BSAs also promoted the receptors for AGEs (RAGEs) and receptor I for TGF-β (TGFR I) markedly with a dose dependence, whereas the Sirt 1 was significantly downregulated by the AGE-BSA at both mRNA and protein levels. Moreover, the Sirt 1 activity manipulation with its activator, resveratrol (RSV), or its inhibitor, EX527, markedly inhibited or ameliorated the AGE-mediated TGF-β upregulation. And the manipulated Sirt 1 activity positively regulated the AGE-induced CD31, whereas it negatively regulated the AGE-induced FSP-1. Thus, Sirt 1 was confirmed to regulate the AGE-induced EndMT via TGF-β. In summary, we found that AGE-BSA induced EndMT in HUVECs via upregulating TGF-β and downregulating Sirt 1, which also negatively regulated TGF-β in the cell. This study implied the EndMT probably as an important mechanism of AGE-induced cardiovascular injury. PMID:25710021

  16. Advanced glycation end-product (AGE) induces apoptosis in human retinal ARPE-19 cells via promoting mitochondrial dysfunction and activating the Fas-FasL signaling.

    PubMed

    Wang, Pu; Xing, Yiqiao; Chen, Changzheng; Chen, Zhen; Qian, Zhimin

    2016-01-01

    Advanced glycation end-products (AGEs) are extremely accumulated in the retinal vascular and epithelial cells of diabetes mellitus (DM) patients, particularly with diabetic retinopathy (DR). To elucidate the pathogenesis of the AGE-induced toxicity to retinal epithelial cells, we investigated the role of Fas-Fas ligand (FasL) signaling and mitochondrial dysfunction in the AGE-induced apoptosis. Results demonstrated that the AGE-BSA- induced apoptosis of retinal ARPE-19 cells. And the AGE-BSA treatment caused mitochondrial dysfunction, via deregulating the B-cell lymphoma 2 (Bcl-2) signaling. Moreover, the Fas/FasL and its downstreamer Caspase 8 were promoted by the AGE-BSA treatment, and the exogenous α-Fas exacerbated the activation of Caspase 3/8. On the other side, the siRNA-mediated knockdown of Fas/FasL inhibited the AGE-BSA-induced apoptosis. Taken together, we confirmed the activation of Fas-FasL signaling and of mitochondrial dysfunction in the AGE-BSA-promoted apoptosis in retinal ARPE-19 cells, implying the important role of Fas-FasL signaling in the DR in DM. PMID:26479732

  17. Beta-D-glucoside protects against advanced glycation end products (AGEs)-mediated diabetic responses by suppressing ERK and inducing PPAR gamma DNA binding.

    PubMed

    Mahali, Sidhartha K; Manna, Sunil K

    2012-12-15

    Accumulation of advanced glycation end products (AGEs), due to excessive amounts of 3- or 4-carbon sugars derived from glucose; cause multiple consequences in diabetic patients and older persons. The transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ), is down regulated in the diabetic condition. Drugs targeting PPARγ were developed for diabetes therapy. We found that AGE inhibited PPARγ activity in different cell types induced by PPARγ activators, like troglitazone, rosiglitazone, oleamide, and anandamide. AGE induced translocation of PPARγ from nucleus to cytoplasm, increased on activation of ERK in cells. Antioxidants that inhibit AGE-induced NF-κB activation by preventing ROI generation were unable to protect AGE-mediated decrease in PPARγ activity. Only mangiferin, a β-D-glucoside, prevented AGE-mediated decrease in PPARγ activity and inhibited phosphorylation of ERK and cytoplasmic translocation of PPARγ. Mangiferin interacts with PPARγ and enhanced its DNA binding activity as predicted by in silico and shown by in vitro DNA-binding activity. Overall, the data suggest that (i) mangiferin inhibited AGE-induced ERK activation thereby inhibited PPARγ phosphorylation and cytoplasmic translocation; (ii) mangiferin interacts with PPARγ and enhances its DNA-binding ability. With these dual effects, mangiferin can be a likely candidate for developing therapeutic drug against diabetes. PMID:23058985

  18. Advanced Glycation End Products (AGE) Potently Induce Autophagy through Activation of RAF Protein Kinase and Nuclear Factor κB (NF-κB).

    PubMed

    Verma, Neeharika; Manna, Sunil K

    2016-01-15

    Advanced glycation end products (AGE) accumulate in diabetic patients and aging people because of high amounts of three- or four-carbon sugars derived from glucose, thereby causing multiple consequences, including inflammation, apoptosis, obesity, and age-related disorders. It is important to understand the mechanism of AGE-mediated signaling leading to the activation of autophagy (self-eating) that might result in obesity. We detected AGE as one of the potent inducers of autophagy compared with doxorubicin and TNF. AGE-mediated autophagy is inhibited by suppression of PI3K and potentiated by the autophagosome maturation blocker bafilomycin. It increases autophagy in different cell types, and that correlates with the expression of its receptor, receptor for AGE. LC3B, the marker for autophagosomes, is shown to increase upon AGE stimulation. AGE-mediated autophagy is partially suppressed by inhibitor of NF-κB, PKC, or ERK alone and significantly in combination. AGE increases sterol regulatory element binding protein activity, which leads to an increase in lipogenesis. Although AGE-mediated lipogenesis is affected by autophagy inhibitors, AGE-mediated autophagy is not influenced by lipogenesis inhibitors, suggesting that the turnover of lipid droplets overcomes the autophagic clearance. For the first time, we provide data showing that AGE induces several cell signaling cascades, like NF-κB, PKC, ERK, and MAPK, that are involved in autophagy and simultaneously help with the accumulation of lipid droplets that are not cleared effectively by autophagy, therefore causing obesity. PMID:26586913

  19. Inhibition of Advanced Glycation End-Product Formation and Antioxidant Activity by Extracts and Polyphenols from Scutellaria alpina L. and S. altissima L.

    PubMed

    Grzegorczyk-Karolak, Izabela; Gołąb, Krzysztof; Gburek, Jakub; Wysokińska, Halina; Matkowski, Adam

    2016-01-01

    Methanolic extracts from the aerial parts and roots of two Scutellaria species, S. alpina and S. altissima, and five polyphenols from these plants demonstrated a significant ability to inhibit the formation of advanced glycation end-products (AGE) in vitro. S. alpina, which is richer in polyphenolic compounds, had strong antiglycation properties. These extracts demonstrated also high activity in the FRAP (ferric-reducing antioxidant power), antiradical (DPPH) and lipid peroxidation inhibition assays. Among the pure compounds, baicalin was the strongest glycation inhibitor (90.4% inhibition at 100 μg/mL), followed by luteolin (85.4%). Two other flavone glycosides had about half of this activity. Verbascoside was similar to the reference drug aminoguanidine (71.2% and 75.9%, respectively). The strong correlation observed between AGE inhibition and total flavonoid content indicated that flavonoids contribute significantly to antiglycation properties. A positive correlation was also observed between antiglycative and antioxidant activities. The studied skullcap species can be considered as a potential source of therapeutic agents for hyperglycemia-related disorders. PMID:27314314

  20. Phenolic acids inhibit the formation of advanced glycation end products in food simulation systems depending on their reducing powers and structures.

    PubMed

    Chen, Hengye; Virk, Muhammad Safiullah; Chen, Fusheng

    2016-06-01

    The concentration of advanced glycation end products (AGEs) in foods, which are formed by Maillard reaction, has demonstrated as risk factors associated with many chronic diseases. The AGEs inhibitory activities of five common phenolic acids (protocatechuic acid, dihydroferulic acid, p-coumaric acid, p-hydroxybenzoic acid and salicylic acid) with different chemical properties had been investigated in two food simulation systems (glucose-bovine serum albumin (BSA) and oleic acid-BSA). The results substantiated that the AGEs inhibitory abilities of phenolic acids in the oleic acid BSA system were much better than the glucose-BSA system for their strong reducing powers and structures. Among them, dihydrogenferulic acid showed strong inhibition of AGEs formation in oleic acid-BSA system at 0.01 mg/mL compared to nonsignificant AGEs inhibitory effect in oleic acid-BSA system at 10-fold higher concentration (0.1 mg/mL). This study suggests that edible plants rich in phenolic acids may be used as AGEs inhibitor during high-fat cooking. PMID:27102241

  1. Effect of Advanced Glycation End Products on Human Thyroglobulin's Antigenicity as Identified by the Use of Sera from Patients with Hashimoto's Thyroiditis and Gestational Diabetes Mellitus

    PubMed Central

    Hatzioannou, A.; Kanistras, I.; Mantzou, E.; Anastasiou, E.; Peppa, M.; Sarantopoulou, V.; Lymberi, P.; Alevizaki, M.

    2015-01-01

    Advanced glycation end products (AGEs) are formed on proteins after exposure to high concentrations of glucose and modify protein's immunogenicity. Herein, we investigated whether the modification of thyroglobulin (Tg) by AGEs influences its antigenicity and immunogenicity. Human Tg was incubated in vitro with increasing concentrations of D-glucose-6-phosphate in order to produce Tgs with different AGE content (AGE-Tg). Native Tg and AGE-Tgs were used in ELISA to assess the serum antibody reactivity of two patient groups, pregnant women with gestational diabetes (GDM), and patients with Hashimoto's thyroiditis (HT). We produced in vitro AGE-Tg with low and high AGE content, 13 and 49 AGE units/mg Tg, respectively. All HT patients' sera presented the same antibody reactivity profile against native Tg and AGE-Tgs, indicating that the modification of Tg by AGEs did not alter its antigenicity. Similarly, the GDM patients' sera did not discriminate among the two forms of Tg, native or artificially glycated, suggesting that the modification of Tg by AGEs might not alter its immunogenicity. The modification of Tg by AGEs has no obvious effect on neither its antigenicity nor, most likely, its immunogenicity. It seems that other Tg modifications might account for the production of aTgAbs in patients with GDM. PMID:26229534

  2. Metformin protects against hyperglycemia-induced cardiomyocytes injury by inhibiting the expressions of receptor for advanced glycation end products and high mobility group box 1 protein.

    PubMed

    Zhang, Ting; Hu, Xiaorong; Cai, Yuli; Yi, Bo; Wen, Zhongyuan

    2014-03-01

    Metformin (MET), an anti-diabetic oral drug with antioxidant properties, has been proved to provide cardioprotective effects in patients with diabetic disease. However, the mechanism is unclear. This study aimd to investigate the effects of MET on the expressions of receptor for advanced glycation end products (RAGE) and high mobility group box 1 protein (HMGB1) in hyperglycemia-treated neonatal rat ventricular myocytes. Cardiocytes were prepared and cultured with high glucose and different concentrations of MET. The expressions of RAGE and HMGB1 were evaluated by Western blot analysis. The superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), lactate dehydrogenase (LDH) and creatine kinase (CK) were measured. After 12 h-incubation, MET significantly inhibited the increase of MDA, TNF-α, LDH and CK levels induced by high glucose, especially at the 5 × 10(-5) to 10(-4 )mol/L concentrations while inhibiting the decrease of SOD level. Meanwhile, RAGE and HMGB1 expression were significantly increased induced by hyperglycaemia for 24 h (P < 0.05). MET inhibited the expressions of RAGE and HMGB1 in a dose-dependent manner, especially at the 5 × 10(-5) to 10(-4 )mol/L concentrations (P < 0.05). In conclusion, our study suggested that MET could reduce hyperglycemia-induced cardiocytes injury by inhibiting the expressions of RAGE and HMGB1. PMID:24420848

  3. Receptor for advanced glycation end-products (RAGE) is overexpressed in human osteosarcoma and promotes the proliferation of osteosarcoma U-2OS cells in vitro.

    PubMed

    Zhang, Q; Jin, Y; Zhao, C F; Wang, W J; Liu, G Y

    2016-01-01

    Osteosarcoma (OS) is an aggressive cancer of the long bones, and usually affects children and young adults. The receptor for advanced glycation end-products (RAGE) has recently been recognized as an oncogenic receptor that binds to different ligands, and promotes the progression of various cancers. However, little is known about the association between RAGE and the pathogenesis of OS. In this study, we first examined the expression of RAGE in OS tissues using immunohistochemical staining, western blotting, and reverse transcription quantitative polymerase chain reaction. We then determined the influence of the overexpressed RAGE on the proliferation of U-2OS cells in vitro. The results showed that RAGE was overexpressed in OS tissues compared with peritumor tissues, at both the mRNA and protein levels, and there was a significant association between overexpressed RAGE and clinicopathological characteristics, such as clinical stage and distant metastasis. Moreover, the overexpression of RAGE in U-2OS cells significantly promoted their proliferation in vitro. In conclusion, this study indicated that RAGE is overexpressed in OS tissue and promotes the proliferation of U-2OS cells. These data imply that RAGE promotes the growth of OS, and is a potential diagnostic biomarker and therapeutic target for the disorder. PMID:27323159

  4. Eplerenone restores 24-h blood pressure circadian rhythm and reduces advanced glycation end-products in rhesus macaques with spontaneous hypertensive metabolic syndrome

    PubMed Central

    Zhang, Yan; Zheng, Wen; Liu, Yuli; Wang, Jue; Peng, Ying; Shang, Haibao; Hou, Ning; Hu, Xiaomin; Ding, Yi; Xiao, Yao; Wang, Can; Zeng, Fanxin; Mao, Jiaming; Zhang, Jun; Ma, Dongwei; Sun, Xueting; Li, Chuanyun; Xiao, Rui-Ping; Zhang, Xiuqin

    2016-01-01

    Hypertension is often associated with metabolic syndrome (MetS), and serves as a risk factor of MetS and its complications. Blood pressure circadian rhythm in hypertensive patients has been suggested to contribute to cardiovascular consequences and organ damage of hypertension. But circadian changes of BP and their response to drugs have not been clearly investigated in non-human primates (NHPs) of MetS with hypertension. Here, we identified 16 elderly, hypertensive MetS rhesus monkeys from our in-house cohort. With implanted telemetry, we investigate BP changes and its circadian rhythm, together with the effect of antihypertensive drugs on BP and its diurnal fluctuation. MetS hypertensive monkeys displayed higher BP, obesity, glucose intolerance, and dyslipidemia. We also confirmed impaired 24-h BP circadian rhythm in MetS hypertensive monkeys. Importantly, Eplerenone, a mineralocorticoid receptor blocker, exerts multiple beneficial effects in MetS hypertensive monkeys, including BP reduction, 24-h BP circadian rhythm restoration, and decreased plasma concentration of inflammation factors and advanced glycation end-products. In summary, we identified a naturally-developed hypertensive MetS NHP model, which is of great value in the studies on pathogenesis of MetS-associated hypertension and development of novel therapeutic strategies. We also provided multiple novel mechanistic insights of the beneficial effect of Eplerenone on MetS with hypertension. PMID:27032687

  5. Expression of the Receptor for Advanced Glycation End Products in Epicardial Fat: Link with Tissue Thickness and Local Insulin Resistance in Coronary Artery Disease.

    PubMed

    Dozio, Elena; Vianello, Elena; Briganti, Silvia; Lamont, John; Tacchini, Lorenza; Schmitz, Gerd; Corsi Romanelli, Massimiliano Marco

    2016-01-01

    Increased expression of receptor for advanced glycation end products (RAGE) in adipose tissue has been associated with inflammation, adipocyte hypertrophy, and impaired insulin signal. Epicardial adipose tissue (EAT), a visceral fat surrounding the myocardium, is potentially involved in the onset/progression of coronary artery disease (CAD). To date, the role of RAGE in EAT has not been explored much. We examined whether the RAGE expression in EAT was associated with EAT adiposity and metabolic dysfunctions normally found in CAD patients. EAT samples were obtained from 33 patients undergoing open-heart surgery. EAT expression of RAGE, GLUT4, adiponenctin, GLO1, HMGB1, TLR-4, and MyD88 was analyzed by microarray. EAT thickness was quantified by echocardiography. Anthropometric measures and clinical parameters were taken. BMI, HOMA-IR, and LAP indices were calculated. With increasing RAGE expression in EAT we observed increases in EAT thickness, reduced expression of GLUT4, adiponectin, and GLO1, and elevations of HMGB1, TLR-4, and MyD88. There were significant correlations between RAGE and EAT thickness and between RAGE and the genes. LAP was higher in patients with increased RAGE expression. Our data suggest that in CAD patients RAGE may be involved in promoting EAT adiposity and metabolic dysfunction, such as impaired insulin signaling. PMID:26788516

  6. Opposing Roles of Membrane and Soluble Forms of the Receptor for Advanced Glycation End Products in Primary Respiratory Syncytial Virus Infection

    PubMed Central

    Miller, Allison L.; Sims, Gary P.; Brewah, Yambasu A.; Rebelatto, Marlon C.; Kearley, Jennifer; Benjamin, Ebony; Keller, Ashley E.; Brohawn, Philip; Herbst, Ronald; Coyle, Anthony J.; Kolbeck, Roland

    2012-01-01

    Respiratory syncytial virus (RSV), a common respiratory pathogen in infants and the older population, causes pulmonary inflammation and airway occlusion that leads to impairment of lung function. Here, we have established a role for receptor for advanced glycation end products (RAGE) in RSV infection. RAGE-deficient (ager−/−) mice were protected from RSV-induced weight loss and inflammation. This protection correlated with an early increase in type I interferons, later decreases in proinflammatory cytokines, and a reduction in viral load. To assess the contribution of soluble RAGE (sRAGE) to RSV-induced disease, wild-type and ager−/− mice were given doses of sRAGE following RSV infection. Of interest, sRAGE treatment prevented RSV-induced weight loss and neutrophilic inflammation to a degree similar to that observed in ager−/− mice. Our work further elucidates the roles of RAGE in the pathogenesis of respiratory infections and highlights the opposing roles of membrane and sRAGE in modulating the host response to RSV infection. PMID:22262795

  7. Impact of Serum High Mobility Group Box 1 and Soluble Receptor for Advanced Glycation End-Products on Subclinical Atherosclerosis in Patients with Granulomatosis with Polyangiitis

    PubMed Central

    de Souza, Alexandre W. S.; de Leeuw, Karina; van Timmeren, Mirjan M.; Limburg, Pieter C.; Stegeman, Coen A.; Bijl, Marc; Westra, Johanna; Kallenberg, Cees G. M.

    2014-01-01

    The objective of this study was to evaluate whether levels of high mobility group box 1 (HMGB1) in granulomatosis with polyangiitis (GPA) patients are associated with carotid atherosclerosis, related to levels of soluble receptor for advanced glycation end-products (sRAGE) and influenced by immunosuppressive or lipid-lowering therapy. Twenty-three GPA patients and 20 controls were evaluated for HMGB1- and sRAGE levels and for carotid atherosclerosis using ultrasound to determine intima-media thickness (IMT). In vitro the effect of atorvastatin on the production of HMGB1 by lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVEC) was assessed. Serum HMGB1 and sRAGE levels did not differ between patients and controls. A negative correlation was found between sRAGE and maximum IMT but HMGB1 and carotid IMT were not related. HMGB1 levels were reduced in GPA patients on statins and prednisolone. In vitro, atorvastatin reduced HMGB1 levels in supernatants of activated HUVEC. In conclusion, carotid IMT is inversely correlated with sRAGE levels but not with HMGB1 levels. Statins and prednisolone are associated with reduced serum HMGB1 levels and atorvastatin decreases HMGB1 release by activated HUVEC in vitro, indicating an additional anti-inflammatory effect of statins. PMID:24776932

  8. Chebulic acid prevents hepatic fibrosis induced by advanced glycation end-products in LX-2 cell by modulating Nrf2 translocation via ERK pathway.

    PubMed

    Koo, Yun-Chang; Pyo, Min Cheol; Nam, Mi-Hyun; Hong, Chung-Oui; Yang, Sung-Yong; Lee, Kwang-Won

    2016-08-01

    Advanced glycation end-products (AGEs) are formed during normal aging, and at an accelerated rate in metabolic syndrome patients. Nonalcoholic steatohepatitis (NASH) can be caused by the AGEs in plasma, while glyceraldehyde-derived AGEs (glycer-AGEs) are significantly higher in the serum of NASH patients. In this study, we investigated the molecular mechanisms of chebulic acid, isolated from Terminalia chebula Retz., in the inhibition of glycer-AGEs induced production of reactive oxygen species (ROS) and collagen accumulation using the LX-2 cell line. Chebulic acid significantly inhibited the induction of ROS and accumulation of collagen proteins by glycer-AGEs. ERK phosphorylation and total nuclear factor E2-related factor 2 (Nrf2) protein expression were induced by chebulic acid in a dose-dependent manner. Chebulic acid was also found to induce translocation of Nrf2 into the nucleus, which was attenuated by inhibition of ERK phosphorylation through treatment with PD98059. Following translocation of Nrf2, chebulic acid induced the protein expressions of catalytic subunit of γ-glutamylcysteine synthetase and glutathione synthesis. Collagen accumulation was also significantly reduced by chebulic acid treatment. The observed effects of chebulic acid were all inhibited by PD98059 treatment. Taken together, these results suggest that chebulic acid prevents the glycer-AGEs-induced ROS formation of LX-2 cells and collagen accumulation by ERK-phosphorylation-mediated Nrf2 nuclear translocation, which causes upregulation of antioxidant protein production. PMID:27021876

  9. Inhibition of Advanced Glycation End Products (AGEs) Accumulation by Pyridoxamine Modulates Glomerular and Mesangial Cell Estrogen Receptor α Expression in Aged Female Mice

    PubMed Central

    Xia, Xiaomei; Cai, Weijing; Choi, Rhea; Striker, Gary E.; Elliot, Sharon J.

    2016-01-01

    Age-related increases in oxidant stress (OS) play a role in regulation of estrogen receptor (ER) expression in the kidneys. In this study, we establish that in vivo 17β-estradiol (E2) replacement can no longer upregulate glomerular ER expression by 21 months of age in female mice (anestrous). We hypothesized that advanced glycation end product (AGE) accumulation, an important source of oxidant stress, contributes to these glomerular ER expression alterations. We treated 19-month old ovariectomized female mice with pyridoxamine (Pyr), a potent AGE inhibitor, in the presence or absence of E2 replacement. Glomerular ERα mRNA expression was upregulated in mice treated with both Pyr and E2 replacement and TGFβ mRNA expression decreased compared to controls. Histological sections of kidneys demonstrated decreased type IV collagen deposition in mice receiving Pyr and E2 compared to placebo control mice. In addition, anti-AGE defenses Sirtuin1 (SIRT1) and advanced glycation receptor 1 (AGER1) were also upregulated in glomeruli following treatment with Pyr and E2. Mesangial cells isolated from all groups of mice demonstrated similar ERα, SIRT1, and AGER1 expression changes to those of whole glomeruli. To demonstrate that AGE accumulation contributes to the observed age-related changes in the glomeruli of aged female mice, we treated mesangial cells from young female mice with AGE-BSA and found similar downregulation of ERα, SIRT1, and AGER1 expression. These results suggest that inhibition of intracellular AGE accumulation with pyridoxamine may protect glomeruli against age-related oxidant stress by preventing an increase of TGFβ production and by regulation of the estrogen receptor. PMID:27428057

  10. Determinants of concentrations of N(ε)-carboxymethyl-lysine and soluble receptor for advanced glycation end products and their associations with risk of pancreatic cancer.

    PubMed

    Duan, Zhigang; Chen, Guoqing; Chen, Liang; Stolzenberg-Solomon, Rachael; Weinstein, Stephanie J; Mannisto, Satu; White, Donna L; Albanes, Demetrius; Jiao, Li

    2014-01-01

    The soluble receptor for advanced glycation end-products (sRAGE) is shown to mitigate pro-inflammatory effects triggered by ligation of RAGE with N(ε)-carboxymethyl-lysine (CML)-AGE or other ligands. We examined the associations among host, lifestyle, and genetic determinants of CML-AGE or sRAGE and risk of pancreatic cancer in the prospective ATBC Study. We obtained baseline exposure information, data on serological and genetic biomarkers from 141 patients with pancreatic cancer and 141 subcohort controls. Stepwise linear and logistic regression models were used for data analysis. Multiple linear regression analyses showed that CML-AGE concentrations were independently inversely correlated with the minor allele of rs640742 of DDOST, physical activity, alcohol consumption, diastolic blood pressure (BP), and positively correlated with heart rate, serum sRAGE and HDL concentrations (P < 0.05). sRAGE concentrations were independently inversely correlated with the 82Ser allele of rs2070600 of RAGE, age, body mass index, heart rate, and serum HDL; and positively correlated with serum CML-AGE, sucrose consumption, and diastolic BP (P < 0.05). The minor allele of rs1035786 of RAGE was associated with reduced risk of pancreatic cancer (any T compared with CC: multivariate OR = 0.61, 95% CI: 0.38-0.98). We identified host metabolic profile, lifestyle and genetic factors that explained approximately 50% of variability of CML-AGE or sRAGE in Finnish men smokers. The association between RAGE SNPs and pancreatic cancer risk warrants further investigation. PMID:25379135

  11. Monocyte Chemotactic Protein-1, Fractalkine, and Receptor for Advanced Glycation End Products in Different Pathological Types of Lupus Nephritis and Their Value in Different Treatment Prognoses

    PubMed Central

    Lan, Lan; Han, Fei; Lang, Xiabing; Chen, Jianghua

    2016-01-01

    Background Early diagnosis is important for the outcome of lupus nephritis (LN). However, the pathological type of lupus nephritis closely related to the clinical manifestations; therefore, the treatment of lupus nephritis depends on the different pathological types. Objective To assess the level of monocyte chemotactic protein (MCP-1), fractalkine (Fkn), and receptor for advanced glycation end product (RAGE) in different pathological types of lupus nephritis and to explore the value of these biomarkers for predicting the prognosis of lupus nephritis. Methods Patients included in this study were assessed using renal biopsy. Class III and class IV were defined as the proliferative group, class V as non-proliferative group, and class V+III and class V+IV as the mixed group. During the follow-up, 40 of 178 enrolled patients had a poor response to the standard immunosuppressant therapy. The level of markers in the different response groups was tested. Results The levels of urine and serum MCP-1, urine and serum fractalkine, and serum RAGE were higher in the proliferative group, and lower in the non-proliferative group, and this difference was significant. The levels of urine and serum MCP-1 and serum RAGE were lower in the poor response group, and these differences were also significant. The relationship between urine MCP-1 and urine and serum fractalkine with the systemic lupus erythematosus disease activity index was evaluated. Conclusion The concentration of cytokines MCP-1, fractalkine, and RAGE may be correlated with different pathology type of lupus nephtitis. Urine and serum MCP-1 and serum RAGE may help in predicting the prognosis prior to standard immunosuppressant therapy. PMID:27458981

  12. Fibroblast growth factor 21 protects mouse brain against D-galactose induced aging via suppression of oxidative stress response and advanced glycation end products formation.

    PubMed

    Yu, Yinhang; Bai, Fuliang; Wang, Wenfei; Liu, Yaonan; Yuan, Qingyan; Qu, Susu; Zhang, Tong; Tian, Guiyou; Li, Siming; Li, Deshan; Ren, Guiping

    2015-06-01

    Fibroblast growth factor 21 (FGF21) is a hormone secreted predominantly in the liver, pancreas and adipose tissue. Recently, it has been reported that FGF21-Transgenic mice can extend their lifespan compared with wild type counterparts. Thus, we hypothesize that FGF21 may play some roles in aging of organisms. In this study d-galactose (d-gal)-induced aging mice were used to study the mechanism that FGF21 protects mice from aging. The three-month-old Kunming mice were subcutaneously injected with d-gal (180mg·kg(-1)·d(-1)) for 8weeks and administered simultaneously with FGF21 (1, 2 or 5mg·kg(-1)·d(-1)). Our results showed that administration of FGF21 significantly improved behavioral performance of d-gal-treated mice in water maze task and step-down test, reduced brain cell damage in the hippocampus, and attenuated the d-gal-induced production of MDA, ROS and advanced glycation end products (AGEs). At the same time, FGF21 also markedly renewed the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total anti-oxidation capability (T-AOC), and decreased the enhanced total cholinesterase (TChE) activity in the brain of d-gal-treated mice. The expression of aldose reductase (AR), sorbitol dehydrogenase (SDH) and member-anchored receptor for AGEs (RAGE) declined significantly after FGF21 treatment. Furthermore, FGF21 suppressed inflamm-aging by inhibiting IκBα degradation and NF-κB p65 nuclear translocation. The expression levels of pro-inflammatory cytokines, such as TNF-α and IL-6, decreased significantly. In conclusion, these results suggest that FGF21 protects the aging mice brain from d-gal-induced injury by attenuating oxidative stress damage and decreasing AGE formation. PMID:25871519

  13. The endothelial cell binding site for advanced glycation end products consists of a complex: an integral membrane protein and a lactoferrin-like polypeptide.

    PubMed

    Schmidt, A M; Mora, R; Cao, R; Yan, S D; Brett, J; Ramakrishnan, R; Tsang, T C; Simionescu, M; Stern, D

    1994-04-01

    Advanced glycation end products (AGEs), formed as the result of the extended interaction of proteins with ketoses, modulate central properties of endothelial cells and mononuclear phagocytes by interacting with a cell surface binding site comprised of a novel integral membrane protein (receptor for AGE = RAGE) and a lactoferrin-like polypeptide (LF-L), the latter having sequence identity to lactoferrin (LF). To further understand this cellular binding site, the interaction of RAGE with LF-L and LF was characterized. By ligand blotting and a solid state competitive binding assay, 125I-LF-L and 125I-LF bound to RAGE immobilized on nitrocellulose membranes or polypropylene tubes in a time-dependent and reversible manner, demonstrating a high affinity component with Kd approximately 100 pM. The interaction of 125I-LF-L and 125I-LF with RAGE was independent of iron in LF and was competed by addition of an excess of unlabeled carboxyl-terminal portion of LF. Cross-linking studies with purified 125I-LF-L and RAGE, in the presence of disuccinimidyl suberate, showed a new, slowly migrating band, corresponding to a complex of RAGE and LF-L, and cross-linking on mouse aortic endothelial cells showed two new slowly migrating bands on immunoblotting visualized with both anti-RAGE IgG and anti-LF-L IgG. These data lead us to propose that the endothelial cell surface binding site for AGEs consists of LF-L bound noncovalently to RAGE anchored in the cell membrane. PMID:8144581

  14. Pigment epithelium-derived factor inhibits advanced glycation end product-elicited mesangial cell damage by blocking NF-kappaB activation.

    PubMed

    Ide, Yuichiro; Matsui, Takanori; Ishibashi, Yuji; Takeuchi, Masayoshi; Yamagishi, Sho-ichi

    2010-09-01

    Advanced glycation end products (AGE), senescent macroprotein derivatives formed at an accelerated rate under hyperglycemic conditions, elicit oxidative stress generation and inflammatory reactions, thus being involved in the development and progression of diabetic nephropathy. Recently, we, along with others, have found that pigment epithelium-derived factor (PEDF), a glycoprotein with potent neuronal differentiating activity, inhibits AGE-elicited endothelial cell damage through its anti-oxidative properties and blocks the progression of experimental diabetic retinopathy. However, a role of PEDF in diabetic nephropathy is not fully understood. In this study, we investigated whether and how PEDF could protect against AGE-elicited mesangial cell damage in vitro. PEDF mRNA and protein levels were decreased by the treatments of AGE. PEDF or neutralizing antibody raised against RAGE (receptor for AGE) was found to inhibit the AGE-induced oxidative stress generation and subsequent NF-kappaB activation in mesangial cells. Further, AGE increased mRNA levels of monocyte chemoattractant protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1) and plasminogen activator inhibitor-1 (PAI-1) in mesangial cells, all of which were prevented by the treatments with PEDF, RAGE antibody or pyrrolidine dithiocarbamate, a NF-kappaB inhibitor. The present results demonstrated for the first time that PEDF blocked the AGE-RAGE-mediated mesangial cell injury by inhibiting NF-kappaB activation via suppression of reactive oxygen species generation. Our present study suggests that substitution of PEDF proteins may be a promising strategy for the treatment of diabetic nephropathy. PMID:20381502

  15. Pigment epithelium-derived factor (PEDF) inhibits proximal tubular cell injury in early diabetic nephropathy by suppressing advanced glycation end products (AGEs)-receptor (RAGE) axis.

    PubMed

    Maeda, Sayaka; Matsui, Takanori; Takeuchi, Masayoshi; Yoshida, Yumiko; Yamakawa, Ryoji; Fukami, Kei; Yamagishi, Sho-ichi

    2011-03-01

    Pigment epithelium-derived factor (PEDF) is a multifunctional glycoprotein with anti-angiogenic and anti-inflammatory properties, and it could block the development and progression of experimental diabetic retinopathy. However, a role for PEDF in early experimental diabetic nephropathy is not fully understood. Advanced glycation end products (AGEs) and their receptor (RAGE) axis stimulates oxidative stress generation and subsequently evokes inflammatory and fibrogenic reactions in renal tubular cells, thereby playing a role in diabetic nephropathy. Therefore, this study investigated whether PEDF could prevent AGE-elicited tubular cell injury in early diabetic nephropathy. Human proximal tubular cells were incubated with or without AGE-bovine serum albumin in the presence or absence of PEDF. Streptozotocin-induced diabetic rats were treated with or without intravenous injection of PEDF for 4 weeks. Gene expression was analyzed by quantitative real-time reverse transcription-polymerase chain reactions. Reactive oxygen species (ROS) was measured with dihydroethidium staining. PEDF or antibodies raised against RAGE inhibited the AGE-induced RAGE gene expression and subsequently reduced ROS generation, monocyte chemoattractant protein-1 (MCP-1) and transforming growth factor-β (TGF-β), fibronectin and type IV collagen mRNA levels in proximal tubular cells. RAGE gene expression, ROS generation and MCP-1 and TGF-β mRNA levels were significantly increased in diabetic kidney, which were suppressed by administration of PEDF. Our present data suggest that PEDF could play a protective role against tubular injury in diabetic nephropathy by attenuating the deleterious effects of AGEs via down-regulation of RAGE expression. Administration of PEDF may offer a promising strategy for halting the development of diabetic nephropathy. PMID:21115116

  16. The effect of an advanced glycation end-product crosslink breaker and exercise training on vascular function in older individuals: a randomized factorial design trial.

    PubMed

    Oudegeest-Sander, Madelijn H; Olde Rikkert, Marcel G M; Smits, Paul; Thijssen, Dick H J; van Dijk, Arie P J; Levine, Benjamin D; Hopman, Maria T E

    2013-12-01

    Aging leads to accumulation of irreversible advanced glycation end-products (AGEs), contributing to vascular stiffening and endothelial dysfunction. When combined with the AGE-crosslink breaker Alagebrium, exercise training reverses cardiovascular aging in experimental animals. This study is the first to examine the effect of Alagebrium, with and without exercise training, on endothelial function, arterial stiffness and cardiovascular risk in older individuals. Forty-eight non-exercising individuals (mean age 70 ± 4 years) without manifest diseases or use of medication were allocated into 4 groups for a 1-year intervention: Exercise training & Alagebrium (200 mg/day); exercise training & placebo; no exercise training & Alagebrium (200 mg/day); and no exercise training & placebo. We performed a maximal exercise test (VO2max) and measured endothelial function using venous occlusion plethysmography and intra-arterial infusion of acetylcholine, sodium nitroprusside and NG-monomethyl-l-arginine. Arterial stiffness was measured using pulse wave velocity. Cardiovascular risk was calculated using the Lifetime Risk Score (LRS). In the exercise training groups, LRS and VO2max improved significantly (23.9 ± 4.5 to 27.2 ± 4.6mLO2/min/kg, p < 0.001). Endothelial response to the vasoactive substances did not change, nor did arterial stiffness in any of the four groups. In conclusion, one year of exercise training significantly improved physical fitness and lifetime risk for cardiovascular disease without affecting endothelial function or arterial stiffness. The use of the AGE-crosslink breaker Alagebrium had no independent effect on vascular function, nor did it potentiate the effect of exercise training. Despite the clinical benefits of exercise training for older individuals, neither exercise training nor Alagebrium (alone or in combination) was able to reverse the vascular effects of decades of sedentary aging. PMID:24400341

  17. Altered Expression of NF- κ B and SP1 after Exposure to Advanced Glycation End-Products and Effects of Neurotrophic Factors in AGEs Exposed Rat Retinas.

    PubMed

    Bikbova, Guzel; Oshitari, Toshiyuki; Baba, Takayuki; Yamamoto, Shuichi

    2015-01-01

    To determine the effect of advanced glycation end-products (AGEs) on neurite regeneration, and also to determine the regenerative effects of different neurotrophic factors (NTFs) on rat retinal explants, the retinas of SD rats were cultured in three-dimensional collagen gels and incubated in 6 types of media: (1) serum-free control culture media; (2) 100 μg/mL AGEs-BSA media; (3) AGEs-BSA + 100 ng/mL neurotrophin-4 (NT-4) media; (4) AGEs-BSA + 100 ng/mL hepatocyte growth factor media; (5) AGEs-BSA + 100 ng/mL glial cell line-derived neurotrophic factor media; or (6) AGEs-BSA + 100 µM tauroursodeoxycholic acid media. After 7 days, the number of regenerating neurites was counted. The explants were immunostained for nuclear factor-κB (NF-κB) and specificity protein 1 (SP1). Statistical analyses were performed by one-way ANOVA. In retinas incubated with AGEs, the numbers of neurites were fewer than in control. All of the NTFs increased the number of neurites, and the increase was more significant in the NT-4 group. The number of NF-κB and SP1 immunopositive cells was higher in retinas exposed to AGEs than in control. All of the NTFs decreased the number of NF-κB immunopositive cells but did not significantly affect SP1 expression. These results demonstrate the potential of the NTFs as axoprotectants in AGEs exposed retinal neurons. PMID:26078979

  18. Total Soluble and Endogenous Secretory Receptor for Advanced Glycation End Products as Predictive Biomarkers of Coronary Heart Disease Risk in Patients With Type 2 Diabetes

    PubMed Central

    Colhoun, Helen M.; Betteridge, D. John; Durrington, Paul; Hitman, Graham; Neil, Andrew; Livingstone, Shona; Charlton-Menys, Valentine; Bao, Weihang; DeMicco, David A.; Preston, Gregory M.; Deshmukh, Harshal; Tan, Kathryn; Fuller, John H.

    2011-01-01

    OBJECTIVE Circulating levels of soluble receptor for advanced glycation end products (sRAGE) likely comprise both a secreted isoform (esRAGE) and wild-type RAGE cleaved from the cell membrane. Both sRAGE and esRAGE have been proposed as biomarkers of cardiovascular disease (CVD), but prospective data are limited. We examined the relationship of sRAGE and esRAGE to incident coronary heart disease (CHD) and stroke in type 2 diabetic patients followed for 3.9 years in a trial of atorvastatin: the Collaborative Atorvastatin Diabetes Study (CARDS). RESEARCH DESIGN AND METHODS We used a nested case-control design sampling all incident cases of CVD with available plasma and randomly selecting three control subjects, who were free of CVD throughout follow-up, per case. Analysis was by Cox regression with adjustment for treatment allocation and relevant covariates. RESULTS sRAGE and esRAGE were strongly correlated (ρ = 0.88) and were both higher in those with lower BMI (P < 0.001), higher adiponectin (P < 0.001), lower estimated glomerular filtration rate (P = 0.009), and white ethnicity (P < 0.001). Both sRAGE and esRAGE were associated with incident CHD events, independently of treatment allocation and the above factors; hazard ratio (HR) = 1.74 (95% CI 1.25–2.41; P = 0.002) for a doubling of the sRAGE level; HR = 1.45 (1.11–1.89; P = 0.006) for a doubling of the esRAGE level. There was no significant association with stroke; HR for sRAGE = 0.66 (0.38–1.14). Atorvastatin, 10 mg daily, did not alter sRAGE. CONCLUSIONS Higher levels of sRAGE and esRAGE are associated with incident CHD but not stroke in type 2 diabetes. PMID:21771973

  19. Tranilast Blocks the Interaction between the Protein S100A11 and Receptor for Advanced Glycation End Products (RAGE) V Domain and Inhibits Cell Proliferation.

    PubMed

    Huang, Yen-Kai; Chou, Ruey-Hwang; Yu, Chin

    2016-07-01

    The human S100 calcium-binding protein A11 (S100A11) is a member of the S100 protein family. Once S100A11 proteins bind to calcium ions at EF-hand motifs, S100A11 changes its conformation, promoting interaction with target proteins. The receptor for advanced glycation end products (RAGE) consists of three extracellular domains, including the V domain, C1 domain, and C2 domain. In this case, the V domain is the target for mutant S100A11 (mS100A11) binding. RAGE binds to the ligands, resulting in cell proliferation, cell growth, and several signal transduction cascades. We used NMR and fluorescence spectroscopy to demonstrate the interactions between mS100A11and RAGE V domain. The tranilast molecule is a drug used for treating allergic disorders. We discovered that the RAGE V domain and tranilast would interact with mS100A11 by using (1)H-(15)N HSQC NMR titrations. According to the results, we obtained two binary complex models from the HADDOCK program, S100A11-RAGE V domain and S100A11-tranilast, respectively. We overlapped two binary complex models with the same orientation of S100A11 homodimer and demonstrated that tranilast would block the binding site between S100A11 and the RAGE V domain. We further utilized a water-soluble tetrazolium-1 assay to confirm this result. We think that the results will be potentially useful in the development of new anti-cancer drugs. PMID:27226584

  20. High-mobility group box 1 and the receptor for advanced glycation end products contribute to lung injury during Staphylococcus aureus pneumonia

    PubMed Central

    2013-01-01

    Introduction Staphylococcus (S.) aureus has emerged as an important cause of necrotizing pneumonia. Lung injury during S. aureus pneumonia may be enhanced by local release of damage associated molecular patterns such as high-mobility group box 1 (HMGB1). In the current study we sought to determine the functional role of HMGB1 and its receptors, toll-like receptor 4 (TLR4) and the receptor for advanced glycation end products (RAGE), in the injurious host response to S. aureus pneumonia. Methods Pneumonia was induced in wild type (Wt), TLR4 deficient (tlr4−/−) and RAGE deficient (rage−/−) mice by intranasal inoculation of 1 × 107 colony-forming units (CFU) of a USA300 S. aureus. In a separate set of experiments, Wt mice were injected intraperitoneally with a monoclonal anti-HMGB1 antibody or an isotype matched control antibody immediately before and every 24 hours after intranasal infection of S. aureus. Mice were sacrificed at 6, 24, 48 or 72 hours after infection for harvesting of blood and organs. Results S. aureus pneumonia was associated with HMGB1 release in the bronchoalveolar compartment peaking after 24 hours. Anti-HMGB1 attenuated lung pathology and protein leak and reduced interleukin-1β release 6 hours after infection, but not at later time points. RAGE deficiency more modestly attenuated lung pathology without influencing protein leak, while TLR4 deficiency did not impact on lung injury. Conclusion These data suggest that HMGB1 and RAGE, but not TLR4, contribute to lung injury accompanying the early phase of S. aureus pneumonia. PMID:24342460

  1. Expression and Significance of High-Mobility Group Protein B1 (HMGB1) and the Receptor for Advanced Glycation End-Product (RAGE) in Knee Osteoarthritis

    PubMed Central

    Sun, Xue-Hui; Liu, Ying; Han, Yun; Wang, Jian

    2016-01-01

    Background This study was performed with the aim to explore the expression of high-mobility group protein B1 (HMGB1) and the receptor for advanced glycation end-product (RAGE) in knee osteoarthritis (KOA) and its clinical significance. Material/Methods A total of 108 synovial tissues selected from KOA patients were included in the experimental group. Seventy-five synovial tissues of knee joints, selected from patients who were clinically and pathologically confirmed without joint lesion, were included in the control group. The mRNA and protein expressions of HMGB1 and RAGE were determined by using RT-PCR and immunohistochemistry, respectively. Western blotting was used for measuring relative protein expression. An ROC curve was drawn to evaluate the diagnostic value of HMGB1 and RAGE for KOA. Results The positive cell number and positive expression intensity of HMGB1 and RAGE in synovial tissue was higher in the experimental group than in the control group. PI for HMGB1 and RAGE expression in KOA patients was positively correlated with clinical classification of X-ray films (P<0.05). HMGB1 and RAGE mRNA expressions, as well as relative protein expression of HMGB1 and RAGE in synovial tissue, were higher in the experimental group than in the control group (all P<0.05). The sensitivity of HMGB1 protein, RAGE protein, HMGB1 mRNA, and RAGE mRNA were 76.9%, 64.8%, 86.1%, and 64.8%, respectively; and the specificity was 100%, 96%, 74.7%, and 80%, respectively. Conclusions The protein and mRNA expressions of HMGB1 and RAGE are both increased in KOA patients, suggesting that they are involved in KOA. PMID:27320800

  2. Cilostazol attenuates the severity of peripheral arterial occlusive disease in patients with type 2 diabetes: the role of plasma soluble receptor for advanced glycation end-products.

    PubMed

    Liu, Jhih-Syuan; Chuang, Tsung-Ju; Chen, Jui-Hung; Lee, Chien-Hsing; Hsieh, Chang-Hsun; Lin, Tsung-Kun; Hsiao, Fone-Ching; Hung, Yi-Jen

    2015-08-01

    Recent studies have demonstrated that the plasma soluble receptor for advanced glycation end-products (sRAGE) play a major role in developing macrovascular complications of type 2 diabetes, including peripheral arterial occlusion disease (PAOD). Cilostazol is an antiplatelet, antithrombotic agent, which has been used for the treatment of PAOD. We hypothesized that cilostazol attenuates the severity of PAOD in patients with type 2 diabetes through the augmentation of plasma sRAGE. Ninety type 2 diabetic patients with PAOD defined as intermittent claudication with ankle-brachial index (ABI) ≦0.9 were recruited for an open-labeled, placebo-controlled study for 52 weeks with oral cilostazol 100 mg twice daily (n = 45) or placebo (n = 45). Fasting plasma sRAGE, endothelial variables of E-selectin, soluble vascular cell adhesion molecule-1 (sVCAM-1), and inflammatory markers of high-sensitivity C-reactive protein (hsCRP) and tumor necrosis factor-α (TNF-α) were determined. After completely the 52-week treatment program, the ABI values were elevated in cilostazol group (P < 0.001). The plasma sRAGE was significantly increased (P = 0.007), and hsCRP, sVCAM, and E-selectin concentrations were significantly decreased (P = 0.028, <0.001 and <0.001, respectively) with cilostazol treatment. In a partial correlation analysis with adjustments for sex and age, the net change of sRAGE significantly correlated with the change of ABI in the cilostazol group (P = 0.043). In a stepwise multiple regression model, only the change with regards to sRAGE was significantly associated with the change of ABI (P = 0.046). Our results suggest that cilostazol may effectively attenuate the severity of PAOD in patients with type 2 diabetes. Plasma sRAGE plays a role as an independent predictor for improving the index of PAOD. PMID:25666934

  3. Evidence that Serum Levels of the Soluble Receptor for Advanced Glycation End-Products are Inversely Associated with Pancreatic Cancer Risk: a Prospective Study

    PubMed Central

    Jiao, Li; Weinstein, Stephanie J.; Albanes, Demetrius; Taylor, Philip R.; Graubard, Barry I.; Virtamo, Jarmo; Stolzenberg-Solomon, Rachael Z.

    2011-01-01

    Cigarette smoking, obesity, type 2 diabetes, and to a less extent, meat cooked at high temperatures are associated with pancreatic cancer. Cigarette smoke and foods cooked at higher temperatures are major environmental sources of advanced glycation end-products (AGEs). AGEs accumulate during hyperglycemia and elicit oxidative stress and inflammation through interaction with the receptor for AGEs (RAGE). Soluble RAGE (sRAGE) acts as an anti-inflammatory factor to neutralize AGEs and block the effects mediated by RAGE. In this study, we investigated the associations of prediagnostic measures of Nε-(carboxymethyl)-lysine (CML)-AGE and sRAGE with pancreatic cancer in a case-cohort study within a cohort of 29,133 Finnish male smokers. Serum samples and exposure information were collected at baseline (1985-1988). We measured CML-AGE, sRAGE, glucose and insulin concentrations in fasting serum from 255 incident pancreatic cancer cases that arose through April 2005 and from 485 randomly sampled subcohort participants. Weighted Cox proportional hazard regression models were used to calculate relative risks (RR) and 95% confidence intervals (CI), adjusted for age, years of smoking and body mass index. CML-AGE and sRAGE were mutually adjusted. CML-AGE levels were not associated with pancreatic cancer (fifth compared with first quintile, RR (95% CI): 0.68 (0.38-1.22), Ptrend = 0.27). In contrast, sRAGE levels were inversely associated with pancreatic cancer (fifth compared with first quintile, RR (95% CI): 0.46 (0.23-0.73), Ptrend = 0.002). Further adjustment for glucose or insulin levels did not change the observed associations. Our findings suggest that sRAGE is inversely associated with pancreatic cancer risk among Finnish male smokers. PMID:21540233

  4. Therapeutic effects of antigen affinity-purified polyclonal anti-receptor of advanced glycation end-product (RAGE) antibodies on cholestasis-induced liver injury in rats.

    PubMed

    Xia, Peng; Deng, Qing; Gao, Jin; Yu, Xiaolan; Zhang, Yang; Li, Jingjing; Guan, Wen; Hu, Jianjun; Tan, Quanhui; Zhou, Liang; Han, Wei; Yuan, Yunsheng; Yu, Yan

    2016-05-15

    Cholestasis leads to acute hepatic injury, fibrosis/cirrhosis, inflammation, and duct proliferation. We investigated whether blocking receptor of advanced glycation end-products (RAGE) with polyclonal anti-RAGE antibodies (anti-RAGE) could regulate acute liver injury and fibrosis in a rat bile duct ligation (BDL) model. Male Wister rats received 0.5mg/kg rabbit anti-RAGE or an equal amount of rabbit IgG by subcutaneous injection twice a week after BDL. Samples of liver tissue and peripheral blood were collected at 14 days after BDL. Serum biochemistry and histology were used to analyze the degree of liver injury. Quantitative real-time PCR (qPCR) and immunohistochemical staining were used to further analyze liver injury. Anti-RAGE improved the gross appearance of the liver and the rat survival rate. Liver tissue histology and relevant serum biochemistry indicated that anti-RAGE attenuated liver necrosis, inflammation, liver fibrosis, and duct proliferation in the BDL model. qPCR and western blotting showed significant reductions in interleukin-1β expression levels in the liver by treatment with anti-RAGE. Anti-RAGE also significantly reduced the mRNA levels of α1(1) collagen (Col1α1) and cholesterol 7α-hydroxylase, and the ratio of tissue inhibitor of matrix metalloproteinase-1 to matrix metalloproteinases (MMPs) in the liver. In addition, anti-RAGE regulated the transcriptional level of Col1α1 and MMP-9 in transforming growth factor-β-induced activated LX-2 cells in vitro. Anti-RAGE was found to inhibit hepatic stellate cell proliferation in vivo and in vitro. Therefore, anti-RAGE can protect the liver from injury induced by BDL in rats. PMID:26970185

  5. Association of vascular endothelial growth factor -634G/C and receptor for advanced glycation end products G82S gene polymorphisms with diabetic retinopathy

    PubMed Central

    Kamal, Asmaa; Abu Eleinen, Khaled; Siam, Ibrahem

    2016-01-01

    AIM To investigate the association of receptor for advanced glycation end products (RAGE) G82S and vascular endothelial growth factor (VEGF) -634 G/C gene polymorphisms with diabetic retinopathy (DR). METHODS Our cross-sectional study included 61 diabetic patients, 12 of them had proliferative diabetic retinopathy (PDR), 15 had non proliferative diabetic retinopathy (NPDR), 34 had no diabetic retinopathy (NDR) and 61 healthy controls. Participants were tested for RAGE G82S and VEGF -634 G/C polymorphisms by polymerase chain reaction-restriction fragment length polymorphism. RESULTS We found a significant association between VEGF -634 G/C polymorphism and PDR as PDR patients had increased incidence of VEGF -634 CC genotype compared to NDR patients [odds ratio for CC vs (GC+GG)=6.5, 95% CI=1.5-27.8, P=0.021]. Also VEGF -634 CC genotype and C allele were significantly higher in the PDR than in NPDR patients, which is a novel finding in our study (P=0.024, 0.009 respectively). The mean triglycerides level was significantly higher in diabetic patients with CC genotype (P=0.01) as compared to patients with other genotypes. All cases and control subjects were of the same heterozygous RAGE 82G/S genotype. CONCLUSION Patients carrying VEGF -634 C polymorphism have a higher risk of PDR development, so VEGF -634 G/C polymorphism could be used as a predictive marker for PDR in diabetic patients. We could not find a significant association between RAGE G82S polymorphism and DR. PMID:27588263

  6. Skin Advanced Glycation End Products Glucosepane and Methylglyoxal Hydroimidazolone Are Independently Associated With Long-term Microvascular Complication Progression of Type 1 Diabetes

    PubMed Central

    Sun, Wanjie; Cleary, Patricia; Gao, Xiaoyu; Sell, David R.; Lachin, John

    2015-01-01

    Six skin collagen advanced glycation end products (AGEs) originally measured near to the time of the Diabetes Control and Complications Trial (DCCT) closeout in 1993 may contribute to the “metabolic memory” phenomenon reported in the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study. We have now investigated whether the addition of four originally unavailable AGEs (i.e., glucosepane [GSPNE], hydroimidazolones of methylglyoxal [MG-H1] and glyoxal, and carboxyethyl-lysine) improves associations with incident retinopathy, nephropathy, and neuropathy events during 13–17 years after DCCT. The complete 10-AGE panel is associated with three-step Early Treatment of Diabetic Retinopathy Study scale worsening of retinopathy (P ≤ 0.002), independent of either mean DCCT or EDIC study A1C level. GSPNE and fructose-lysine (furosine [FUR]) correlate with retinopathy progression, independently of A1C level. The complete panel also correlates with microalbuminuria (P = 0.008) and FUR with nephropathy independently of A1C level (P ≤ 0.02). Neuropathy correlates with the complete panel despite adjustment for A1C level (P ≤ 0.005). MG-H1 and FUR are dominant, independent of A1C level (P < 0.0001), whereas A1C loses significance after adjustment for the AGEs. Overall, the added set of four AGEs enhances the association of the original panel with progression risk of retinopathy and neuropathy (P < 0.04) but not nephropathy, while GSPNE and MG-H1 emerge as the principal new risk factors. Skin AGEs are robust long-term markers of microvascular disease progression, emphasizing the importance of early and sustained implementation of intensive therapy. PMID:25187362

  7. Skin advanced glycation end products glucosepane and methylglyoxal hydroimidazolone are independently associated with long-term microvascular complication progression of type 1 diabetes.

    PubMed

    Genuth, Saul; Sun, Wanjie; Cleary, Patricia; Gao, Xiaoyu; Sell, David R; Lachin, John; Monnier, Vincent M

    2015-01-01

    Six skin collagen advanced glycation end products (AGEs) originally measured near to the time of the Diabetes Control and Complications Trial (DCCT) closeout in 1993 may contribute to the "metabolic memory" phenomenon reported in the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study. We have now investigated whether the addition of four originally unavailable AGEs (i.e., glucosepane [GSPNE], hydroimidazolones of methylglyoxal [MG-H1] and glyoxal, and carboxyethyl-lysine) improves associations with incident retinopathy, nephropathy, and neuropathy events during 13-17 years after DCCT. The complete 10-AGE panel is associated with three-step Early Treatment of Diabetic Retinopathy Study scale worsening of retinopathy (P ≤ 0.002), independent of either mean DCCT or EDIC study A1C level. GSPNE and fructose-lysine (furosine [FUR]) correlate with retinopathy progression, independently of A1C level. The complete panel also correlates with microalbuminuria (P = 0.008) and FUR with nephropathy independently of A1C level (P ≤ 0.02). Neuropathy correlates with the complete panel despite adjustment for A1C level (P ≤ 0.005). MG-H1 and FUR are dominant, independent of A1C level (P < 0.0001), whereas A1C loses significance after adjustment for the AGEs. Overall, the added set of four AGEs enhances the association of the original panel with progression risk of retinopathy and neuropathy (P < 0.04) but not nephropathy, while GSPNE and MG-H1 emerge as the principal new risk factors. Skin AGEs are robust long-term markers of microvascular disease progression, emphasizing the importance of early and sustained implementation of intensive therapy. PMID:25187362

  8. Glucagon-like peptide-1 counteracts the detrimental effects of Advanced Glycation End-Products in the pancreatic beta cell line HIT-T 15

    SciTech Connect

    Puddu, A.; Storace, D.; Durante, A.; Odetti, P.; Viviani, G.L.

    2010-07-30

    Research highlights: {yields} GLP-1 prevents AGEs-induced cell death. {yields} GLP-1 prevents AGEs-induced oxidative stress. {yields} GLP-1 ameliorated AGEs-induced cell dysfunction. {yields} GLP-1 attenuates AGEs-induced RAGE increment. {yields} GLP-1 counteracts AGEs-induced pancreatic cell death and dysfunction. -- Abstract: Advanced Glycation End-Products (AGEs), a group of compounds resulting from the non-enzymatic reaction of reducing sugars with the free amino group of proteins, are implicated in diabetic complications. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T 15 to high concentrations of AGEs significantly decreases cell proliferation and insulin secretion, and affects transcription factors regulating insulin gene transcription. The glucagon-like peptide-1 (GLP-1) is an incretin hormone that increases proinsulin biosynthesis, stimulates insulin secretion, and improves pancreatic beta-cell viability. The aim of this work was to investigate the effects of GLP-1 on the function and viability of HIT-T 15 cells cultured with AGEs. HIT-T 15 cells were cultured for 5 days in presence of AGEs alone, or supplemented with 10 nmol/l GLP-1. Cell viability, insulin secretion, redox balance, and expression of the AGEs receptor (RAGE) were then determined. The results showed that GLP-1 protected beta cell against AGEs-induced cell death preventing both apoptosis and necrosis. Moreover, addition of GLP-1 to the AGEs culture medium restored the redox balance, improved the responsiveness to glucose, and attenuated AGEs-induced RAGE expression. These findings provide evidence that GLP-1 protects beta cells from the dangerous effects of AGEs.

  9. Dietary consumption of meat, fat, animal products and advanced glycation end-products and the risk of barrett’s esophagus

    PubMed Central

    Jiao, Li; Kramer, Jennifer R.; Chen, Liang; Rugge, Massimo; Parente, Paola; Verstovsek, Gordana; Alsarraj, Abeer; El-Serag, Hashem B.

    2013-01-01

    Background Advanced glycation end-products (AGEs) are found in high quantity in high-fat foods and meat cooked at high temperature. AGEs have been shown to contribute to chronic inflammation and oxidative stress in humans. Aim To investigate the associations between consumption of meat, fat and AGEs, and risk of Barrett’s esophagus (BE). Methods We conducted a case-control study using data from the patients who were scheduled for elective esophagogastroduodenoscopy (EGD) and from a random sample of patients who were identified at primary care clinics. Daily consumption of meat, fat and Nε-(carboxymethyl) lysine (CML), a major type of AGEs, was derived from the food frequency questionnaire (FFQ). Multivariate logistic regression models were used to estimate the odds ratio (OR) and its 95% confidence interval (CI) for BE. Results A total of 151 cases with BE and 777 controls without BE completed the FFQ. The multivariate OR (95% CI) for BE was 1.91 (1.07–3.38) for total meat, 1.80 (1.02–3.16) for saturated fat, and 1.63 (0.96–2.76) for CML-AGE, when the highest tertile of intake was compared with the lowest. The association for total meat was attenuated to 1.61 (0.82–3.16), and that for saturated fat to 1.54 (0.81–2.94) after adjusting for CML-AGE. Conclusions Higher consumption of total meat, saturated fat or possibly CML-AGE was associated with an increased risk of BE. CML-AGE may partly explain the association between total meat and saturated fat consumption and risk of BE. PMID:23957669

  10. Contrasting roles for the receptor for advanced glycation end-products on structural cells in allergic airway inflammation vs. airway hyperresponsiveness.

    PubMed

    Taniguchi, Akihiko; Miyahara, Nobuaki; Waseda, Koichi; Kurimoto, Etsuko; Fujii, Utako; Tanimoto, Yasushi; Kataoka, Mikio; Yamamoto, Yasuhiko; Gelfand, Erwin W; Yamamoto, Hiroshi; Tanimoto, Mitsune; Kanehiro, Arihiko

    2015-10-15

    The receptor for advanced glycation end-products (RAGE) is a multiligand receptor that belongs to the immunoglobulin superfamily. RAGE is reported to be involved in various inflammatory disorders; however, studies that address the role of RAGE in allergic airway disease are inconclusive. RAGE-sufficient (RAGE+/+) and RAGE-deficient (RAGE-/-) mice were sensitized to ovalbumin, and airway responses were monitored after ovalbumin challenge. RAGE-/- mice showed reduced eosinophilic inflammation and goblet cell metaplasia, lower T helper type 2 (Th2) cytokine production from spleen and peribronchial lymph node mononuclear cells, and lower numbers of group 2 innate lymphoid cells in the lung compared with RAGE+/+ mice following sensitization and challenge. Experiments using irradiated, chimeric mice showed that the mice expressing RAGE on radio-resistant structural cells but not hematopoietic cells developed allergic airway inflammation; however, the mice expressing RAGE on hematopoietic cells but not structural cells showed reduced airway inflammation. In contrast, absence of RAGE expression on structural cells enhanced innate airway hyperresponsiveness (AHR). In the absence of RAGE, increased interleukin (IL)-33 levels in the lung were detected, and blockade of IL-33 receptor ST2 suppressed innate AHR in RAGE-/- mice. These data identify the importance of RAGE expressed on lung structural cells in the development of allergic airway inflammation, T helper type 2 cell activation, and group 2 innate lymphoid cell accumulation in the airways. RAGE on lung structural cells also regulated innate AHR, likely through the IL-33-ST2 pathway. Thus manipulating RAGE represents a novel therapeutic target in controlling allergic airway responses. PMID:26472810

  11. Advanced glycation end-products induce skeletal muscle atrophy and dysfunction in diabetic mice via a RAGE-mediated, AMPK-down-regulated, Akt pathway.

    PubMed

    Chiu, Chen-Yuan; Yang, Rong-Sen; Sheu, Meei-Ling; Chan, Ding-Cheng; Yang, Ting-Hua; Tsai, Keh-Sung; Chiang, Chih-Kang; Liu, Shing-Hwa

    2016-02-01

    Diabetic myopathy, a less studied complication of diabetes, exhibits the clinical observations characterized by a less muscle mass, muscle weakness and a reduced physical functional capacity. Accumulation of advanced glycation end-products (AGEs), known to play a role in diabetic complications, has been identified in ageing human skeletal muscles. However, the role of AGEs in diabetic myopathy remains unclear. Here, we investigated the effects of AGEs on myogenic differentiation and muscle atrophy in vivo and in vitro. We also evaluated the therapeutic potential of alagebrium chloride (Ala-Cl), an inhibitor of AGEs. Muscle fibre atrophy and immunoreactivity for AGEs, Atrogin-1 (a muscle atrophy marker) and phosphorylated AMP-activated protein kinase (AMPK) expressions were markedly increased in human skeletal muscles from patients with diabetes as compared with control subjects. Moreover, in diabetic mice we found increased blood AGEs, less muscle mass, lower muscular endurance, atrophic muscle size and poor regenerative capacity, and increased levels of muscle AGE and receptor for AGE (RAGE), Atrogin-1 and phosphorylated AMPK, which could be significantly ameliorated by Ala-Cl. Furthermore, in vitro, AGEs (in a dose-dependent manner) reduced myotube diameters (myotube atrophy) and induced Atrogin-1 protein expression in myotubes differentiated from both mouse myoblasts and primary human skeletal muscle-derived progenitor cells. AGEs exerted a negative regulation of myogenesis of mouse and human myoblasts. Ala-Cl significantly inhibited the effects of AGEs on myotube atrophy and myogenesis. We further demonstrated that AGEs induced muscle atrophy/myogenesis impairment via a RAGE-mediated AMPK-down-regulation of the Akt signalling pathway. Our findings support that AGEs play an important role in diabetic myopathy, and that an inhibitor of AGEs may offer a therapeutic strategy for managing the dysfunction of muscle due to diabetes or ageing. PMID:26586640

  12. Advanced glycation end-products induced VEGF production and inflammatory responses in human synoviocytes via RAGE-NF-κB pathway activation.

    PubMed

    Chen, Ying-Ju; Chan, Ding-Cheng; Chiang, Chih-Kang; Wang, Ching-Chia; Yang, Ting-Hua; Lan, Kuo-Cheng; Chao, Sung-Chuan; Tsai, Keh-Sung; Yang, Rong-Sen; Liu, Shing-Hwa

    2016-05-01

    Aging and diabetes are known to be the major cause to affect the progression of osteoarthritis (OA). Advanced glycation end products (AGEs) have been observed to accumulate in various organs especially in joint tissue and do damage to the joint tissue during aging and diabetes. Synovial angiogenesis and inflammation are observed across the full range of OA severity. The signaling pathway of AGEs on vascular endothelial growth factor (VEGF) production and inflammatory responses in synoviocytes are still unclear. Here, we investigated the role of receptor for AGEs (RAGE) and the signaling pathway involved in AGEs-induced VEGF production and inflammatory responses in human synoviocytes. Human synoviocytes were cultured and treated with AGEs (25-100 µg/ml). AGEs significantly induced the protein expressions of cyclooxygenase-2 (COX-2) and VEGF and the productions of prostaglandin-E2 (PGE2), VEGF, interleukin-6 (IL-6), and metalloproteinase-13 (MMP-13) in human synoviocytes in a dose-dependent manner. Moreover, AGEs markedly activated the phosphorylations of IκB kinase (IKK)α/β, IκBα, and nuclear factor (NF)-κB-p65 proteins in human synoviocytes in a time-dependent manner. Treatment with neutralizing antibody for RAGE statistically significantly decreased the AGEs-induced increase in COX-2, VEGF, PGE2, IL-6, and MMP13 and AGEs-activated NF-κB pathway activation. Taken together, these findings indicate that AGEs are capable of inducing VEGF production and inflammatory responses via RAGE-NF-κB pathway activation in human synoviocytes. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:791-800, 2016. PMID:26497299

  13. Aliskiren attenuates bleomycin-induced pulmonary fibrosis in rats: focus on oxidative stress, advanced glycation end products, and matrix metalloproteinase-9.

    PubMed

    Abuelezz, Sally A; Hendawy, Nevien; Osman, Wesam M

    2016-08-01

    Pulmonary fibrosis is a progressive lung disorder with high mortality rate and limited successful treatment. This study was designed to assess the potential anti-oxidant and anti-fibrotic effects of aliskiren (Alsk) during bleomycin (BLM)-induced pulmonary fibrosis. Male Wistar rats were used as control untreated or treated with the following: a single dose of 2.5 mg/kg of BLM endotracheally and BLM and Alsk (either low dose 30 mg/kg/day or high dose 60 mg/kg/day), and another group was given Alsk 60 mg/kg/day alone. Alsk was given by gavage. Alsk anti-oxidant and anti-fibrotic effects were assessed. BLM significantly increased relative lung weight and the levels of lactate dehydrogenase and total and differential leucocytic count in bronchoalveolar lavage that was significantly ameliorated by high-dose Alsk treatment. As markers of oxidative stress, BLM caused a significant increase in the levels of lipid peroxides and nitric oxide accompanied with a significant decrease of superoxide dismutase and glutathione transferase enzymes. High-dose Alsk treatment restored these markers toward normal values. Alsk counteracted the overexpression of advanced glycation end products, matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinases-1 in lung tissue induced by BLM. Fibrosis assessed by measuring hydroxyproline content, which markedly increased in the BLM group, was also significantly reduced by Alsk. These were confirmed by histopathological and immunohistochemical examination which revealed that Alsk attenuates signs of pulmonary fibrosis and decreased the overexpressed MMP-9 and transforming growth factor β1. Collectively, these findings indicate that Alsk has a potential anti-fibrotic effect beside its anti-oxidant activity. PMID:27154762

  14. Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

    SciTech Connect

    Matsui, Takanori; Yamagishi, Sho-ichi; Takeuchi, Masayoshi; Ueda, Seiji; Fukami, Kei; Okuda, Seiya

    2010-07-23

    Research highlights: {yields} Nifedipine inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma}. {yields} GW9662 treatment alone increased RAGE mRNA levels in tubular cells. {yields} Nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-{beta} gene expression in tubular cells, all of which were blocked by GW9662. -- Abstract: There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression

  15. Effect of Moringa oleifera on advanced glycation end-product formation and lipid metabolism gene expression in HepG2 cells.

    PubMed

    Sangkitikomol, W; Rocejanasaroj, A; Tencomnao, T

    2014-01-01

    In Thai traditional medicine, Moringa oleifera is used for the treatment of diabetes and hyperlipidemia. Oxidative stress plays a major role in the pathogenesis of many degenerative diseases, such as hyperlipidemia, diabetes mellitus, and cardiovascular disease. We evaluated the antioxidant effect of M. oleifera extract (MOE) for reduction of advanced glycation end-product (AGE) formation, cell viability, oxidative stress, and lipid metabolism gene expression in HepG2 cells. We found that the lyophilized form of MOE in 80% ethanol possessed mean (± SD) total antioxidant, polyphenolic, and flavonoid contents of 9307 ± 364 TE mM/kg dry mass, 218 ± 1 GE mM/kg dry mass, and 286 ± 12 QE mM/kg dry mass, determined using an oxygen radical absorbance capacity assay, a Folin Ciocalteu phenol assay, and a total flavonoids assay, respectively. Concentrations of 2.5-10.0 mg/mL MOE could inhibit AGE-formation by 10-45%, and 100-1000 mg/L MOE reduced intracellular oxidative stress (P < 0.05) in a dose-dependent manner in the DCFH-DA assay. However, MOE induced cytotoxicity at high doses (2000-3000 mg/L), as shown by the MTT assay. MOE significantly downregulated the mRNA expression of the HMG-CoAR, PPARα1, and PPARγ genes (P < 0.05). We concluded that M. oleifera could have benefits for human health by reducing oxidative stress and AGE formation. Moreover, M. oleifera may reduce cholesterol and lipid synthesis by suppression of HMG-CoAR, PPARα1, and PPARγ gene expression, thereby maintaining lipid homeostasis. PMID:24615037

  16. Interaction of the S100A6 mutant (C3S) with the V domain of the receptor for advanced glycation end products (RAGE)

    SciTech Connect

    Mohan, Sepuru K. Gupta, Arun A. Yu, Chin

    2013-05-03

    Highlights: •The halo human S100A6 (C3S) NMR chemical shifts were assigned. •The interactions between S100A6m and RAGE V domain was investigated by ITC. •The residues involved in the S100A6m–RAGE V domain binding were mapped by {sup 1}H–{sup 15}N HSQC titration. •S100A6–RAGE V domain tetrameric complex model was generated from NMR studies. •The S100A6–RAGE V domain interface regions were elucidated based on HADDOCK model. -- Abstract: S100A6 is involved in several vital biological functions, such as calcium sensing and cell proliferation. It is a homodimeric protein that belongs to the S100 protein family. The receptor for advanced glycation end products (RAGE) has been shown to play a role in the progression of various disease conditions, such as diabetes and immune/inflammatory disorders. Information regarding the association of RAGE with S100 proteins at a molecular level is useful to understand the diversity of the RAGE signaling pathways. In this report, biomolecular NMR techniques were utilized for the resonance assignment of the C3S mutation in human S100A6 and characterizing its interaction with the RAGE V domain. Further binding affinity between S100A6m and the RAGE V domain was determined by isothermal titration calorimetric studies. HADDOCK was used to generate a heterotetramer model of the S100A6m–RAGE V domain complex. This model provides an important insights into the S100–RAGE cellular signaling pathway.

  17. Genetics of Plasma Soluble Receptor for Advanced Glycation End-Products and Cardiovascular Outcomes in a Community-based Population: Results from the Atherosclerosis Risk in Communities Study.

    PubMed

    Maruthur, Nisa M; Li, Man; Halushka, Marc K; Astor, Brad C; Pankow, James S; Boerwinkle, Eric; Coresh, Josef; Selvin, Elizabeth; Kao, Wen Hong Linda

    2015-01-01

    Plasma soluble Receptor for Advanced Glycation End-products (sRAGE) is a strong marker of vascular outcomes although evidence on the direction of association is mixed. Compared to whites, blacks have lower levels of sRAGE. We hypothesized that genetic determinants of sRAGE would help clarify the causal role of sRAGE and the black-white difference in sRAGE levels. We conducted a genome-wide analysis of sRAGE in whites and blacks from the Atherosclerosis Risk in Communities Study. Median plasma sRAGE levels were lower in blacks than whites (728 vs. 1067 pg/ml; P<0.0001). The T (vs. C) allele of rs2070600, a missense variant in AGER, the gene encoding RAGE, was associated with approximately 50% lower sRAGE levels in both whites (N = 1,737; P = 7.26x10-16; minor allele frequency (MAF) = 0.04) and blacks (N = 581; P = 0.02; MAF = 0.01). In blacks, the T (vs. C) allele of rs2071288, intronic to AGER, was associated with 43% lower sRAGE levels (P = 2.22x10-8; MAF = 0.10) and was nearly absent in whites. These AGER SNPs explained 21.5% and 26% of the variation in sRAGE in blacks and whites, respectively, but did not explain the black-white difference in sRAGE. These SNPs were not significantly associated with incident death, coronary heart disease, diabetes, heart failure, or chronic kidney disease in whites (N = 8,130-9,017) or blacks (N = 2,293-2,871) (median follow up ~20 years). We identified strong genetic determinants of sRAGE that did not explain the large black-white difference in sRAGE levels or clearly influence risk of clinical outcomes, suggesting that sRAGE may not be a causal factor in development of these outcomes. PMID:26083729

  18. Identifying Advanced Glycation End Products as a Major Source of Oxidants in Aging: Implications for the Management and/or Prevention of Reduced Renal Function in Elderly Persons

    PubMed Central

    Vlassara, Helen; Uribarri, Jaime; Ferrucci, Luigi; Cai, Weijing; Torreggiani, Massimo; Post, James B.; Zheng, Feng; Striker, Gary E.

    2016-01-01

    Summary Aging is characterized by increasing inflammation and oxidant stress (OS). Reduced renal function was present in more than 20% of normal-aged individuals sampled in the National Health and Nutrition Examination Survey (NHANES) cross-sectional study of the US population. Longitudinal studies in the United States and Italy showed that renal function does not decline in some individuals, suggesting that a search for causes of the loss of renal function in some persons might be indicated and interventions to reduce this outcome should be sought. Because advanced glycation end products (AGEs) induce both inflammation and OS, accumulate with age, and primarily are excreted by the kidney, one outcome of reduced renal function in aging could be decreased AGE disposal. The build-up of AGEs with reduced renal function could contribute to inflammation, increased oxidant stress, and accumulation of AGEs in aging. In fact, results from a longitudinal study of normal aging adults in Italy showed that the most significant correlation with mortality was the level of renal function. A clear link between inflammation, OS, AGEs, and chronic disease was shown in studies of mice that showed that reduction of AGE levels by drugs or decreased intake of AGEs reduces chronic kidney disease (CKD) and cardiovascular disease of aging. The data support a role for AGEs in the development of renal lesions in aging mice and reveal that AGEs in the diet are very important contributors to renal and cardiovascular lesions. AGEs signal through two receptors, one of which is anti-inflammatory (AGER1) and the other is proinflammatory (RAGE). Overexpression of AGER1 protects against OS and acute vascular injury. The reduction of AGEs in the diet is as efficient in preventing aging-related cardiovascular and renal lesions in mice as that seen with calorie restriction. Studies in normal adults of all ages and those with CKD suggest that the findings in mice may be directly applicable to both aging

  19. Advanced glycation end products (AGEs) co-localize with AGE receptors in the retinal vasculature of diabetic and of AGE-infused rats.

    PubMed Central

    Stitt, A. W.; Li, Y. M.; Gardiner, T. A.; Bucala, R.; Archer, D. B.; Vlassara, H.

    1997-01-01

    Advanced glycation end products (AGEs), formed from the nonenzymatic glycation of proteins and lipids with reducing sugars, have been implicated in many diabetic complications; however, their role in diabetic retinopathy remains largely unknown. Recent studies suggest that the cellular actions of AGEs may be mediated by AGE-specific receptors (AGE-R). We have examined the immunolocalization of AGEs and AGE-R components R1 and R2 in the retinal vasculature at 2, 4, and 8 months after STZ-induced diabetes as well as in nondiabetic rats infused with AGE bovine serum albumin for 2 weeks. Using polyclonal or monoclonal anti-AGE antibodies and polyclonal antibodies to recombinant AGE-R1 and AGE-R2, immunoreactivity (IR) was examined in the complete retinal vascular tree after isolation by trypsin digestion. After 2, 4, and 8 months of diabetes, there was a gradual increase in AGE IR in basement membrane. At 8 months, pericytes, smooth muscle cells, and endothelial cells of the retinal vessels showed dense intracellular AGE IR. AGE epitopes stained most intensely within pericytes and smooth muscle cells but less in basement membrane of AGE-infused rats compared with the diabetic group. Retinas from normal or bovine-serum-albumin-infused rats were largely negative for AGE IR. AGE-R1 and -R2 co-localized strongly with AGEs of vascular endothelial cells, pericytes, and smooth muscle cells of either normal, diabetic, or AGE-infused rat retinas, and this distribution did not vary with each condition. The data indicate that AGEs accumulate as a function of diabetes duration first within the basement membrane and then intracellularly, co-localizing with cellular AGE-Rs. Significant AGE deposits appear within the pericytes after long-term diabetes or acute challenge with AGE infusion conditions associated with pericyte damage. Co-localization of AGEs and AGE-Rs in retinal cells points to possible interactions of pathogenic significance. Images Figure 1 Figure 2 Figure 3 PMID

  20. iRAGE as a novel carboxymethylated peptide that prevents advanced glycation end product-induced apoptosis and endoplasmic reticulum stress in vascular smooth muscle cells.

    PubMed

    Maltais, Jean-Sébastien; Simard, Elie; Froehlich, Ulrike; Denault, Jean-Bernard; Gendron, Louis; Grandbois, Michel

    2016-02-01

    Advanced glycation end-products (AGE) and the receptor for AGE (RAGE) have been linked to numerous diabetic vascular complications. RAGE activation promotes a self-sustaining state of chronic inflammation and has been shown to induce apoptosis in various cell types. Although previous studies in vascular smooth muscle cells (VSMC) showed that RAGE activation increases vascular calcification and interferes with their contractile phenotype, little is known on the potential of RAGE to induce apoptosis in VSMC. Using a combination of apoptotic assays, we showed that RAGE stimulation with its ligand CML-HSA promotes apoptosis of VSMC. The formation of stress granules and the increase in the level of the associated protein HuR point toward RAGE-dependent endoplasmic reticulum (ER) stress, which is proposed as a key contributor of RAGE-induced apoptosis in VSMC as it has been shown to promote cell death via numerous mechanisms, including up-regulation of caspase-9. Chronic NF-κB activation and modulation of Bcl-2 homologs are also suspected to contribute to RAGE-dependent apoptosis in VSMC. With the goal of reducing RAGE signaling and its detrimental impact on VSMC, we designed a RAGE antagonist (iRAGE) derived from the primary amino acid sequence of HSA. The resulting CML peptide was selected for the high glycation frequency of the primary sequence in the native protein in vivo. Pretreatment with iRAGE blocked 69.6% of the increase in NF-κB signaling caused by RAGE activation with CML-HSA after 48h. Preincubation with iRAGE was successful in reducing RAGE-induced apoptosis, as seen through enhanced cell survival by SPR and reduced PARP cleavage. Activation of executioner caspases was 63.5% lower in cells treated with iRAGE before stimulation with CML-HSA. To our knowledge, iRAGE is the first antagonist shown to block AGE-RAGE interaction and we propose the molecule as an initial candidate for drug discovery. PMID:26707030

  1. Effects of methanolic extracts from edible plants on endogenous secretory receptor for advanced glycation end products induced by the high glucose incubation in human endothelial cells

    PubMed Central

    Okada, Yoshinori; Okada, Mizue

    2015-01-01

    Background: In diabetic populations, endogenous secretory receptor for advanced glycation end products (esRAGE) levels may be related to the degree of diabetic complications or to the protection from diabetic complications. Objective: We investigated the impact of 29 methanolic extracts from edible plants on esRAGE production in human umbilical vein endothelial cells (HUVECs) cultured in high (4.5 g/L) glucose. Materials and Methods: Edible plants were minced, and extracts were obtained with methanol overnight. The methanolic extracts from 29 edible plants were evaporated in a vacuum. For screening study purposes, HUVECs were seeded in culture dishes (1.5 × 105 cells). Then, HUVECs were incubated with 1 g/L or 4.5 g/L of glucose in SFM CS-C medium treated with methanolic extracts from edible plants (MEEP) for 96 h. Determination of esRAGE production in the cell culture-derived supernatants was performed by colorimetric ELISA. The 8-hydroxydeoxyguanosine (8-OHdG) level was determined by using the 8-OHdG Check ELISA kit. Peroxynitrite-dependent oxidation of 2’, 7’-dichlorodihydrofluorescein to 2’, 7’-dichlorofluorescein was estimated based on the method described by Crow. Because MEEP were methanolic extracts, we measured their total phenolic content (TPC). TPC was measured with a modified version of the Folin–Ciocalteu method. Results: The results showed eight extracts increased esRAGE production. The extract from white radish sprouts showed the highest esRAGE production activity, and then eggplant, carrot peel, young sweet corn, Jew's marrow, broad bean, Japanese radish and cauliflower. In order to understand the mechanism of esRAGE production, the eight extracts were examined for DNA damage, peroxynitrite scavenging activity, and TPC in correlation with their esRAGE production. The results showed esRAGE production correlates with the peroxynitrite level and TPC. Conclusion: This study supports the utilization of these eight extracts in folk medicine for

  2. Assessment of the concentrations of various advanced glycation end-products in beverages and foods that are commonly consumed in Japan.

    PubMed

    Takeuchi, Masayoshi; Takino, Jun-Ichi; Furuno, Satomi; Shirai, Hikari; Kawakami, Mihoko; Muramatsu, Michiru; Kobayashi, Yuka; Yamagishi, Sho-Ichi

    2015-01-01

    Dietary consumption has recently been identified as a major environmental source of pro-inflammatory advanced glycation end-products (AGEs) in humans. It is disputed whether dietary AGEs represent a risk to human health. Nε-(carboxymethyl)lysine (CML), a representative AGE compound found in food, has been suggested to make a significant contribution to circulating CML levels. However, recent studies have found that the dietary intake of AGEs is not associated with plasma CML concentrations. We have shown that the serum levels of glyceraldehyde-derived AGEs (Glycer-AGEs), but not hemoglobin A1c, glucose-derived AGEs (Glu-AGEs), or CML, could be used as biomarkers for predicting the progression of atherosclerosis and future cardiovascular events. We also detected the production/accumulation of Glycer-AGEs in normal rats administered Glu-AGE-rich beverages. Therefore, we assessed the concentrations of various AGEs in a total of 1,650 beverages and foods that are commonly consumed in Japan. The concentrations of four kinds of AGEs (Glu-AGEs, fructose-derived AGEs (Fru-AGEs), CML, and Glycer-AGEs) were measured with competitive enzyme-linked immunosorbent assays involving immunoaffinity-purified specific antibodies. The results of the latter assays indicated that Glu-AGEs and Fru-AGEs (especially Glu-AGEs), but not CML or Glycer-AGEs, are present at appreciable levels in beverages and foods that are commonly consumed by Japanese. Glu-AGEs, Fru-AGEs, CML, and Glycer-AGEs exhibited concentrations of ≥85%, 2-12%, <3%, and trace amounts in the examined beverages and ≥82%, 5-15%, <3%, and trace amounts in the tested foods, respectively. The results of the present study indicate that some lactic acid bacteria beverages, carbonated drinks, sugar-sweetened fruit drinks, sports drinks, mixed fruit juices, confectionery (snacks), dried fruits, cakes, cereals, and prepared foods contain markedly higher Glu-AGE levels than other classes of beverages and foods. We provide

  3. The diagnostic utility and tendency of the soluble receptor for advanced glycation end products (sRAGE) in exudative pleural effusion

    PubMed Central

    Sim, Yun Su; Kim, Dong Gyu

    2016-01-01

    Background The soluble receptor for advanced glycation end products (sRAGE) may have an inflammatory or homeostatic function in lung tissue. The aim of this study was to assess the usefulness of sRAGE as a diagnostic marker for exudative pleural effusions, which are common manifestations of a variety of diseases. Methods Patients with an undiagnosed pleural effusion were prospectively enrolled between January 2013 and January 2015. Samples of blood and pleural fluid were centrifuged and the supernatant stored at −70 °C. The levels of sRAGE in serum and pleural fluid were determined using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. Results In total 47 patients, 21 patients were diagnosed with a tuberculous effusion, and the groups diagnosed with parapneumonic or malignant effusions comprised 13 patients each. The serum sRAGE levels for tuberculosis were significantly elevated [median, 1,291 pg/mL; interquartile range (IQR), 948–1,711 pg/mL] when compared with those for both pneumonia (median, 794 pg/mL; IQR, 700–1,255 pg/mL) and lung cancer (median, 886 pg/mL; IQR, 722–1,285 pg/mL) (P=0.029). The pleural sRAGE levels for pneumonia (median, 1,763 pg/mL; IQR, 1,262–4,431 pg/mL) were lower than those for both tuberculosis (median, 5,081 pg/mL; IQR, 3,300–6,004 pg/mL) and lung cancer (median, 4,936 pg/mL; IQR, 3,282–7,018 pg/mL) (P=0.009) The receiver operating characteristic (ROC) curve analysis selected 896 pg/mL as the best cutoff value in the sRAGE serum level for tuberculosis [sensitivity, 86%; specificity 58%; area under the curve (AUC) =0.727, P=0.008]. For the pleural effusion sRAGE level, the ROC curve analysis selected 2,231 pg/mL as the best cutoff value for pneumonia (sensitivity, 91%; specificity, 62%, AUC =0.792, P=0.002). Conclusions Among patients with exudative effusion, pleural and serum sRAGE measurements may be useful supportive diagnostic tools in the evaluation of ambiguous pleural effusion. Furthermore

  4. Assessment of the Concentrations of Various Advanced Glycation End-Products in Beverages and Foods That Are Commonly Consumed in Japan

    PubMed Central

    Takeuchi, Masayoshi; Takino, Jun-ichi; Furuno, Satomi; Shirai, Hikari; Kawakami, Mihoko; Muramatsu, Michiru; Kobayashi, Yuka; Yamagishi, Sho-ichi

    2015-01-01

    Dietary consumption has recently been identified as a major environmental source of pro-inflammatory advanced glycation end-products (AGEs) in humans. It is disputed whether dietary AGEs represent a risk to human health. Nε-(carboxymethyl)lysine (CML), a representative AGE compound found in food, has been suggested to make a significant contribution to circulating CML levels. However, recent studies have found that the dietary intake of AGEs is not associated with plasma CML concentrations. We have shown that the serum levels of glyceraldehyde-derived AGEs (Glycer-AGEs), but not hemoglobin A1c, glucose-derived AGEs (Glu-AGEs), or CML, could be used as biomarkers for predicting the progression of atherosclerosis and future cardiovascular events. We also detected the production/accumulation of Glycer-AGEs in normal rats administered Glu-AGE-rich beverages. Therefore, we assessed the concentrations of various AGEs in a total of 1,650 beverages and foods that are commonly consumed in Japan. The concentrations of four kinds of AGEs (Glu-AGEs, fructose-derived AGEs (Fru-AGEs), CML, and Glycer-AGEs) were measured with competitive enzyme-linked immunosorbent assays involving immunoaffinity-purified specific antibodies. The results of the latter assays indicated that Glu-AGEs and Fru-AGEs (especially Glu-AGEs), but not CML or Glycer-AGEs, are present at appreciable levels in beverages and foods that are commonly consumed by Japanese. Glu-AGEs, Fru-AGEs, CML, and Glycer-AGEs exhibited concentrations of ≥85%, 2–12%, <3%, and trace amounts in the examined beverages and ≥82%, 5–15%, <3%, and trace amounts in the tested foods, respectively. The results of the present study indicate that some lactic acid bacteria beverages, carbonated drinks, sugar-sweetened fruit drinks, sports drinks, mixed fruit juices, confectionery (snacks), dried fruits, cakes, cereals, and prepared foods contain markedly higher Glu-AGE levels than other classes of beverages and foods. We provide

  5. Dietary consumption of advanced glycation end products and pancreatic cancer in the prospective NIH-AARP Diet and Health Study12345

    PubMed Central

    Stolzenberg-Solomon, Rachael; Zimmerman, Thea Palmer; Duan, Zhigang; Chen, Liang; Kahle, Lisa; Risch, Adam; Subar, Amy F; Cross, Amanda J; Hollenbeck, Albert; Vlassara, Helen; Striker, Gary; Sinha, Rashmi

    2015-01-01

    Background: Advanced glycation end products (AGEs) are a heterogeneous group of compounds present in uncooked foods as well as in foods cooked at high temperatures. AGEs have been associated with insulin resistance, oxidative stress, and chronic inflammation in patients with diabetes. Dietary AGEs are an important contributor to the AGE pool in the body. Nϵ-(carboxymethyl)lysine (CML) AGE is one of the major biologically and chemically well-characterized AGE markers. The consumption of red meat, which is CML-AGE rich, has been positively associated with pancreatic cancer in men. Objectives: With the use of a published food CML-AGE database, we estimated the consumption of CML AGE in the prospective NIH-AARP Diet and Health Study and evaluated the association between CML-AGE consumption and pancreatic cancer and the mediating effect of CML AGE on the association between red meat consumption and pancreatic cancer. Design: Multivariate Cox proportional hazard regression models were used to estimate HRs and 95% CIs for pancreatic cancer. Results: During an average of 10.5 y of follow-up, we identified 2193 pancreatic cancer cases (1407 men and 786 women) from 528,251 subjects. With the comparison of subjects in the fifth and the first quintiles of CML-AGE consumption, we observed increased pancreatic cancer risk in men (HR: 1.43; 95% CI: 1.06, 1.93, P-trend = 0.003) but not women (HR: 1.14; 95% CI: 0.76, 1.72, P-trend = 0.42). Men in the highest quintile of red meat consumption had higher risk of pancreatic cancer (HR: 1.35; 95% CI: 1.07, 1.70), which attenuated after adjustment for CML-AGE consumption (HR: 1.20; 95% CI: 0.95, 1.53). Conclusion: Dietary CML-AGE consumption was associated with modestly increased risk of pancreatic cancer in men and may partially explain the positive association between red meat and pancreatic cancer. The NIH-AARP Diet and Health Study was registered at clinicaltrials.gov as NCT00340015. PMID:25527756

  6. High-mobility group box 1 inhibits HCO(3)(-) absorption in medullary thick ascending limb through a basolateral receptor for advanced glycation end products pathway.

    PubMed

    Good, David W; George, Thampi; Watts, Bruns A

    2015-10-15

    High-mobility group box 1 (HMGB1) is a damage-associated molecule implicated in mediating kidney dysfunction in sepsis and sterile inflammatory disorders. HMGB1 is a nuclear protein released extracellularly in response to infection or injury, where it interacts with Toll-like receptor 4 (TLR4) and other receptors to mediate inflammation. Previously, we demonstrated that LPS inhibits HCO(3)(-) absorption in the medullary thick ascending limb (MTAL) through a basolateral TLR4-ERK pathway (Watts BA III, George T, Sherwood ER, Good DW. Am J Physiol Cell Physiol 301: C1296-C1306, 2011). Here, we examined whether HMGB1 could inhibit HCO(3)(-) absorption through the same pathway. Adding HMGB1 to the bath decreased HCO(3)(-) absorption by 24% in isolated, perfused rat and mouse MTALs. In contrast to LPS, inhibition by HMGB1 was preserved in MTALs from TLR4(-/-) mice and was unaffected by ERK inhibitors. Inhibition by HMGB1 was eliminated by the receptor for advanced glycation end products (RAGE) antagonist FPS-ZM1 and by neutralizing anti-RAGE antibody. Confocal immunofluorescence showed expression of RAGE in the basolateral membrane domain. Inhibition of HCO(3)(-) absorption by HMGB1 through RAGE was additive to inhibition by LPS through TLR4 and to inhibition by Gram-positive bacterial molecules through TLR2. Bath amiloride, which selectively prevents inhibition of MTAL HCO(3)(-) absorption mediated through Na⁺/H⁺ exchanger 1 (NHE1), eliminated inhibition by HMGB1. We conclude that HMGB1 inhibits MTAL HCO(3)(-) absorption through a RAGE-dependent pathway distinct from TLR4-mediated inhibition by LPS. These studies provide new evidence that HMGB1-RAGE signaling acts directly to impair the transport function of renal tubules. They reveal a novel paradigm for sepsis-induced renal tubule dysfunction, whereby exogenous pathogen-associated molecules and endogenous damage-associated molecules act directly and independently to inhibit MTAL HCO(3)(-) absorption through

  7. Green tea polyphenol epigallocatechin-3-gallate inhibits advanced glycation end product-induced expression of tumor necrosis factor-α and matrix metalloproteinase-13 in human chondrocytes

    PubMed Central

    Rasheed, Zafar; Anbazhagan, Arivarasu N; Akhtar, Nahid; Ramamurthy, Sangeetha; Voss, Frank R; Haqqi, Tariq M

    2009-01-01

    Introduction The major risk factor for osteoarthritis (OA) is aging, but the mechanisms underlying this risk are only partly understood. Age-related accumulation of advanced glycation end products (AGEs) can activate chondrocytes and induce the production of proinflammatory cytokines and matrix metalloproteinases (MMPs). In the present study, we examined the effect of epigallocatechin-3-gallate (EGCG) on AGE-modified-BSA (AGE-BSA)-induced activation and production of TNFα and MMP-13 in human OA chondrocytes. Methods Human chondrocytes were derived from OA cartilage by enzymatic digestion and stimulated with in vitro-generated AGE-BSA. Gene expression of TNFα and MMP-13 was measured by quantitative RT-PCR. TNFα protein in culture medium was determined using cytokine-specific ELISA. Western immunoblotting was used to analyze the MMP-13 production in the culture medium, phosphorylation of mitogen-activated protein kinases (MAPKs), and the activation of NF-κB. DNA binding activity of NF-κB p65 was determined using a highly sensitive and specific ELISA. IκB kinase (IKK) activity was determined using an in vitro kinase activity assay. MMP-13 activity in the culture medium was assayed by gelatin zymography. Results EGCG significantly decreased AGE-stimulated gene expression and production of TNFα and MMP-13 in human chondrocytes. The inhibitory effect of EGCG on the AGE-BSA-induced expression of TNFα and MMP-13 was mediated at least in part via suppression of p38-MAPK and JNK activation. In addition, EGCG inhibited the phosphorylating activity of IKKβ kinase in an in vitro activity assay and EGCG inhibited the AGE-mediated activation and DNA binding activity of NF-κB by suppressing the degradation of its inhibitory protein IκBα in the cytoplasm. Conclusions These novel pharmacological actions of EGCG on AGE-BSA-stimulated human OA chondrocytes provide new suggestions that EGCG or EGCG-derived compounds may inhibit cartilage degradation by suppressing AGE

  8. Soluble receptor for advanced glycation end products in COPD: relationship with emphysema and chronic cor pulmonale: a case-control study

    PubMed Central

    2011-01-01

    Background The receptor for advanced glycation end products (RAGE) is a multiligand signal transduction receptor that can initiate and perpetuate inflammation. Its soluble isoform (sRAGE) acts as a decoy receptor for RAGE ligands, and is thought to afford protection against inflammation. With the present study, we aimed at determining whether circulating sRAGE is correlated with emphysema and chronic cor pulmonale in chronic obstructive pulmonary disease (COPD). Methods In 200 COPD patients and 201 age- and sex-matched controls, we measured lung function by spirometry, and sRAGE by ELISA method. We also measured the plasma levels of two RAGE ligands, N-epsilon-carboxymethyl lysine and S100A12, by ELISA method. In the COPD patients, we assessed the prevalence and severity of emphysema by computed tomography (CT), and the prevalence of chronic cor pulmonale by echocardiography. Multiple quantile regression was used to assess the effects of emphysema, chronic cor pulmonale, smoking history, and comorbid conditions on the three quartiles of sRAGE. Results sRAGE was significantly lower (p = 0.007) in COPD patients (median 652 pg/mL, interquartile range 484 to 1076 pg/mL) than in controls (median 869 pg/mL, interquartile range 601 to 1240 pg/mL), and was correlated with the severity of emphysema (p < 0.001), the lower the level of sRAGE the greater the degree of emphysema on CT. The relationship remained statistically significant after adjusting for smoking history and comorbid conditions. In addition, sRAGE was significantly lower in COPD patients with chronic cor pulmonale than in those without (p = 0.002). Such difference remained statistically significant after adjusting for smoking history, comorbidities, and emphysema severity. There was no significant difference in the plasma levels of the two RAGE ligands between cases and controls. Conclusions sRAGE is significantly lower in patients with COPD than in age- and sex-matched individuals without airflow obstruction

  9. Advanced Glycation End Products Affect Osteoblast Proliferation and Function by Modulating Autophagy Via the Receptor of Advanced Glycation End Products/Raf Protein/Mitogen-activated Protein Kinase/Extracellular Signal-regulated Kinase Kinase/Extracellular Signal-regulated Kinase (RAGE/Raf/MEK/ERK) Pathway.

    PubMed

    Meng, Hong-Zheng; Zhang, Wei-Lin; Liu, Fei; Yang, Mao-Wei

    2015-11-20

    The interaction between advanced glycation end products (AGEs) and receptor of AGEs (RAGE) is associated with the development and progression of diabetes-associated osteoporosis, but the mechanisms involved are still poorly understood. In this study, we found that AGE-modified bovine serum albumin (AGE-BSA) induced a biphasic effect on the viability of hFOB1.19 cells; cell proliferation was stimulated after exposure to low dose AGE-BSA, but cell apoptosis was stimulated after exposure to high dose AGE-BSA. The low dose AGE-BSA facilitates proliferation of hFOB1.19 cells by concomitantly promoting autophagy, RAGE production, and the Raf/MEK/ERK signaling pathway activation. Furthermore, we investigated the effects of AGE-BSA on the function of hFOB1.19 cells. Interestingly, the results suggest that the short term effects of low dose AGE-BSA increase osteogenic function and decrease osteoclastogenic function, which are likely mediated by autophagy and the RAGE/Raf/MEK/ERK signal pathway. In contrast, with increased treatment time, the opposite effects were observed. Collectively, AGE-BSA had a biphasic effect on the viability of hFOB1.19 cells in vitro, which was determined by the concentration of AGE-BSA and treatment time. A low concentration of AGE-BSA activated the Raf/MEK/ERK signal pathway through the interaction with RAGE, induced autophagy, and regulated the proliferation and function of hFOB1.19 cells. PMID:26472922

  10. Expression and purification of the soluble isoform of human receptor for advanced glycation end products (sRAGE) from Pichia pastoris.

    PubMed

    Ostendorp, Thorsten; Weibel, Mirjam; Leclerc, Estelle; Kleinert, Peter; Kroneck, Peter M H; Heizmann, Claus W; Fritz, Günter

    2006-08-18

    RAGE is a multi-ligand receptor involved in various human diseases including diabetes, cancer or Alzheimer's disease. Engagement of RAGE by its ligands triggers activation of key cellular signalling pathways such as the MAP kinase and NF-kappaB pathways. Whereas the main isoform of RAGE is a transmembrane receptor with both extra- and intracellular domains, a secreted soluble isoform (sRAGE), corresponding to the extracellular part only, has the ability to block RAGE signalling and suppress cellular activation. Administration of sRAGE to animal models of cancer or multiple sclerosis blocked successfully tumour growth and the course of the autoimmune disease. These findings demonstrate that sRAGE may have a potential as therapeutic. We present here a fast and simple purification protocol of sRAGE from the yeast Pichia pastoris. The identity of the protein was confirmed by mass spectrometry and Western blot. The protein was N-glycosylated and 95-98% pure as judged by SDS-PAGE. PMID:16806067

  11. Hypoxia-induced increases in glucose uptake do not cause oxidative injury or advanced glycation end-product (AGE) formation in vascular endothelial cells.

    PubMed

    Viator, Ryan J; Khader, Heba; Hingorani, Neha; Long, Sara; Solodushko, Victor; Fouty, Brian

    2015-07-01

    An increase in glucose uptake by endothelial cells exposed to hyperglycemia is the presumed initiating event that causes systemic vascular disease in individuals with diabetes. Diabetics do not develop clinically significant pulmonary vascular disease, however, despite the pulmonary circulation's exposure to the same level of glucose. We hypothesized that pulmonary artery endothelial cells are protected from the detrimental effects of hyperglycemia because they take up less glucose than endothelial cells in the systemic circulation, either because of intrinsic differences between the two cell types or because the lower oxygen tension in the pulmonary arterial blood depresses glucose uptake. To test this hypothesis, we exposed normoglycemic and hyperglycemic bovine pulmonary artery (PAECs) and aortic endothelial cells (AECs) from the same animal to progressively lower oxygen tensions and determined glucose uptake. In contrast with our initial hypothesis, we detected no significant difference in glucose uptake between the two cell types. Furthermore, glucose uptake in both PAECs and AECs increased, not decreased, as the oxygen tension dropped; this oxygen-dependent increase in glucose uptake in endothelial cells predominated over the hyperglycemia-mediated decrease in glucose uptake that has been reported by others. Despite the increase in glucose uptake at lower oxygen tensions, we detected no corresponding increase in protein carbonylation or advanced glycation endproducts. These results demonstrate that small physiologically relevant changes in oxygen tension can have an important impact on glucose uptake in endothelial cells. These results also demonstrate that an increase in glucose uptake, by itself, is not sufficient to generate ROS-mediated protein carbonylation or increase intracellular advanced glycation endproducts in vascular endothelial cells. PMID:26177960

  12. Fine tuning of 4,6-bisphenyl-2-(3-alkoxyanilino)pyrimidine focusing on the activity-sensitive aminoalkoxy moiety for a therapeutically useful inhibitor of receptor for advanced glycation end products (RAGE).

    PubMed

    Han, Young Taek; Kim, Kyeojin; Son, Dohyun; An, Hongchan; Kim, Hee; Lee, Jeeyeon; Park, Hyun-Ju; Lee, Jeewoo; Suh, Young-Ger

    2015-02-01

    Through the fine tuning of the activity-sensitive aminoalkoxy moiety of 4,6-bisphenyl-2-(3-alkoxyanilino)pyrimidine as a novel inhibitor of the receptor for advanced glycation end products (RAGE), the tertiary amine was elucidated as an essential part associated with RAGE inhibition. On the basis of this finding, a 3-(N,N-dimethylamino)pyrrolidine analog 12o was identified as a therapeutically useful RAGE inhibitor with improved activity and solubility. Molecular modeling studies predicted that the improved inhibitory activity is induced by additional hydrogen bonds between the nitrogen atom of the pyrrolidine ring and Arg48 and by an interaction between the dimethylamino-substituent of the pyrrolidine moiety and a relatively hydrophobic groove in the RAGE binding site. PMID:25533401

  13. Nucleophilic compounds decrease advanced glycation end products (AGEs) from ascorbic acid in the hSVCT2 transgenic mouse model of lenticular aging

    PubMed Central

    Fan, Xingjun; Monnier, Vincent M

    2008-01-01

    Purpose Senile cataracts are associated with oxidation, fragmentation, cross-linking, insolubilization, and yellow pigmentation of lens crystallins. This process is partially explained by advanced glycation endproducts (AGEs) from ascorbic acid (ASA), as unequivocally demonstrated in our hSVCT2 transgenic mouse(PNAS 103:16912, 2006). We now present the first pharmacological intervention study against ascorbylation in these mice. Methods Five groups of mice (10 mice/group) were fed from two to nine months a diet containing 0.1% (wt/wt) aminoguanidine (AG), pyridoxamine (PM), penicillamine (PA), and nucleophilic compounds NC-I and NC-II. AGEs were determined in crystallin digests using HPLC, LC-MS or GC-MS. In vitro incubations of lens protein extract with ASA or dehydroascorbic aicd (DHA) were also performed. Results ASA level increased ~10 fold in all groups and was unaffected by treatment. AGEs were several fold increased in transgenic compared to control lenses. Body weight, food intake, lenticular glutathione and glycated lysine level were unaltered. In vitro, all compounds inhibited AGE formation. In vivo, NC-I and NC-II significantly decreased protein fluorescence at λex335/em385 (p=0.045, 0.017, respectively) and λex370/em440 (p=0.029, 0.007, respectively). Other inhibitors had no effect. After 7 months, only NC-1 and NC-2 induced a 50 % reduction in pentosidine (n.s, p=0.035 respectively). NC-1 also decreased carboxymethyllysine (CML) (p=0.032) and carboxyethyllysine (CEL) (p= n.s). Fluorescent crosslink K2P was decreased by NC-1, NC-2, AG and PM (p= n.s). Conclusions Pharmacologically blocking protein ascorbylation with absorbable guanidino compounds is feasible and may represent a new strategy for the delay of age-related nuclear sclerosis of the lens. PMID:18421088

  14. The receptor for advanced glycation end products (RAGE) is a cellular binding site for amphoterin. Mediation of neurite outgrowth and co-expression of rage and amphoterin in the developing nervous system.

    PubMed

    Hori, O; Brett, J; Slattery, T; Cao, R; Zhang, J; Chen, J X; Nagashima, M; Lundh, E R; Vijay, S; Nitecki, D

    1995-10-27

    The receptor for advanced glycation end products (RAGE), a newly-identified member of the immunoglobulin superfamily, mediates interactions of advanced glycation end product (AGE)-modified proteins with endothelium and other cell types. Survey of normal tissues demonstrated RAGE expression in situations in which accumulation of AGEs would be unexpected, leading to the hypothesis that under physiologic circumstances, RAGE might mediate interaction with ligands distinct from AGEs. Sequential chromatography of bovine lung extract identified polypeptides with M(r) values of approximately 12,000 (p12) and approximately 23,000 (p23) which bound RAGE. NH2-terminal and internal protein sequence data for p23 matched that reported previously for amphoterin. Amphoterin purified from rat brain or recombinant rat amphoterin bound to purified sRAGE in a saturable and dose-dependent manner, blocked by anti-RAGE IgG or a soluble form of RAGE (sRAGE). Cultured embryonic rat neurons, which express RAGE, displayed dose-dependent binding of 125I-amphoterin which was prevented by blockade of RAGE using antibody to the receptor or excess soluble receptor (sRAGE). A functional correlate of RAGE-amphoterin interaction was inhibition by anti-RAGE F(ab')2 and sRAGE of neurite formation by cortical neurons specifically on amphoterin-coated substrates. Consistent with a potential role for RAGE-amphoterin interaction in development, amphoterin and RAGE mRNA/antigen were co-localized in developing rat brain. These data indicate that RAGE has physiologically relevant ligands distinct from AGEs which are likely, via their interaction with the receptor, to participate in physiologic processes outside of the context of diabetes and accumulation of AGEs. PMID:7592757

  15. Inhibiting receptor for advanced glycation end product (AGE) and oxidative stress involved in the protective effect mediated by glucagon-like peptide-1 receptor on AGE induced neuronal apoptosis.

    PubMed

    Chen, Song; Yin, Lei; Xu, Zheng; An, Feng-Mao; Liu, Ai-Ran; Wang, Ying; Yao, Wen-Bing; Gao, Xiang-Dong

    2016-01-26

    Our previous study has demonstrated that glucagon-like peptide-1 (GLP-1) receptor agonist could protect neurons from advanced glycation end products (AGEs) toxicity in vitro. However, further studies are still needed to clarify the molecular mechanism of this GLP-1 receptor -dependent action. The present study mainly focused on the effect of GLP-1 receptor agonists against the receptor for advanced glycation end products (RAGE) signal pathway and the mechanism underlying this effect of GLP-1. Firstly the data based on the SH-GLP-1R(+) and SH-SY5Y cells confirmed our previous finding that GLP-1 receptor could mediate the protective effect against AGEs. The assays of the protein activity and of the mRNA level revealed that apoptosis-related proteins such as caspase-3, caspase-9, Bax and Bcl-2 were involved. Additionally, we found that both GLP-1 and exendin-4 could reduce AGEs-induced reactive oxygen species (ROS) accumulation by suppressing the activity of nicotinamide adenine dinucleotide phosphate-oxidase. Interestingly, we also found that GLP-1 receptor activation could attenuate the abnormal expression of the RAGE in vitro and in vivo. Furthermore, based on the analysis of the protein expression and translocation level of transcription factor nuclear factor-κB (NF-κB), and the use of GLP-1 receptor antagonist exendin(9-39) and NF-κB inhibitor pyrrolidine dithiocarbamate, we found that the effect mediated by GLP-1 receptor could alleviate the over expression of RAGE induced by ligand via the suppression of NF-κB. In summary, the results indicated that inhibiting RAGE/oxidative stress was involved in the protective effect of GLP-1 on neuron cells against AGEs induced apoptosis. PMID:26679229

  16. Mangiferin suppressed advanced glycation end products (AGEs) through NF-κB deactivation and displayed anti-inflammatory effects in streptozotocin and high fat diet-diabetic cardiomyopathy rats.

    PubMed

    Hou, Jun; Zheng, Dezhi; Fung, Gabriel; Deng, Haoyu; Chen, Lin; Liang, Jiali; Jiang, Yan; Hu, Yonghe

    2016-03-01

    Given the importance of the aggregation of advanced glycation end products (AGEs) and cardiac inflammation in the onset and progression of diabetic cardiomyopathy (DCM), our objective in this study was to demonstrate the cardioprotective effect of mangiferin, an antidiabetic and anti-inflammatory agent, on diabetic rat model. The DCM model was established by a high-fat diet and a low dose of streptozotocin. DCM rats were treated orally with mangiferin (20 mg/kg) for 16 weeks. Serum and left ventricular myocardium were collected for determination of inflammatory cytokines. AGEs mRNA and protein expression of nuclear factor kappa B (NF-κB) and receptor for AGEs (RAGE) in myocardium were assayed by real-time PCR and Western blot. ROS levels were measured by dihydroethidium fluorescence staining. NF-κB binding activity was assayed by TransAM NF-κB p65 ELISA kit. Chronic treatment with mangiferin decreased the levels of myocardial enzymes (CK-MB, LDH) and inflammatory mediators (TNF-α, IL-1β). Meanwhile, NF-κB is inhibited by the reduction of nuclear translocation of p65 subunit, and mangiferin reduced AGE production and decreased the mRNA and protein expression of RAGE in DCM rats. Our data indicated that mangiferin could significantly ameliorate DCM by preventing the release of inflammatory cytokines, and inhibiting ROS accumulation, AGE/RAGE production, and NF-κB nuclear translocation, suggesting that mangiferin treatment might be beneficial in DCM. PMID:26751764

  17. Advanced Glycation End Products Impair Glucose-Stimulated Insulin Secretion of a Pancreatic β-Cell Line INS-1-3 by Disturbance of Microtubule Cytoskeleton via p38/MAPK Activation

    PubMed Central

    You, Jia; Xu, Shiqing; Zhang, Wenjian; Fang, Qing; Liu, Honglin; Peng, Liang; Deng, Tingting

    2016-01-01

    Advanced glycation end products (AGEs) are believed to be involved in diverse complications of diabetes mellitus. Overexposure to AGEs of pancreatic β-cells leads to decreased insulin secretion and cell apoptosis. Here, to understand the cytotoxicity of AGEs to pancreatic β-cells, we used INS-1-3 cells as a β-cell model to address this question, which was a subclone of INS-1 cells and exhibited high level of insulin expression and high sensitivity to glucose stimulation. Exposed to large dose of AGEs, even though more insulin was synthesized, its secretion was significantly reduced from INS-1-3 cells. Further, AGEs treatment led to a time-dependent increase of depolymerized microtubules, which was accompanied by an increase of activated p38/MAPK in INS-1-3 cells. Pharmacological inhibition of p38/MAPK by SB202190 reversed microtubule depolymerization to a stabilized polymerization status but could not rescue the reduction of insulin release caused by AGEs. Taken together, these results suggest a novel role of AGEs-induced impairment of insulin secretion, which is partially due to a disturbance of microtubule dynamics that resulted from an activation of the p38/MAPK pathway.

  18. Association of advanced glycation end products with A549 cells, a human pulmonary epithelial cell line, is mediated by a receptor distinct from the scavenger receptor family and RAGE.

    PubMed

    Nakano, Nahoko; Fukuhara-Takaki, Kaori; Jono, Tadashi; Nakajou, Keisuke; Eto, Nobuaki; Horiuchi, Seikoh; Takeya, Motohiro; Nagai, Ryoji

    2006-05-01

    Cellular interactions with advanced glycation end products (AGE)-modified proteins are known to induce several biological responses, not only endocytic uptake and degradation, but also the induction of cytokines and growth factors, combined responses that may be linked to the development of diabetic vascular complications. In this study we demonstrate that A549 cells, a human pulmonary epithelial cell line, possess a specific binding site for AGE-modified bovine serum albumin (AGE-BSA) (K(d) = 27.8 nM), and additionally for EN-RAGE (extracellular newly identified RAGE binding protein) (K(d) = 118 nM). Western blot and RT-PCR analysis showed that RAGE (receptor for AGE) is highly expressed on A549 cells, while the expression of other known AGE-receptors such as galectin-3 and SR-A (class A scavenger receptor), are below the level of detection. The binding of (125)I-AGE-BSA to these cells is inhibited by unlabeled AGE-BSA, but not by EN-RAGE. In contrast, the binding of (125)I-EN-RAGE is significantly inhibited by unlabeled EN-RAGE and soluble RAGE, but not by AGE-BSA. Our results indicate that A549 cells possess at least two binding sites, one specific for EN-RAGE and the other specific for AGE-BSA. The latter receptor on A549 cells is distinct from the scavenger receptor family and RAGE. PMID:16751589

  19. Apical-to-basolateral transport of amyloid-β peptides through blood-brain barrier cells is mediated by the receptor for advanced glycation end-products and is restricted by P-glycoprotein.

    PubMed

    Candela, Pietra; Gosselet, Fabien; Saint-Pol, Julien; Sevin, Emmanuel; Boucau, Marie-Christine; Boulanger, Eric; Cecchelli, Roméo; Fenart, Laurence

    2010-01-01

    Several studies have highlighted the close relationship between Alzheimer's disease (AD) and alterations in the bidirectional transport of amyloid-β (Aβ) peptides across the blood-brain barrier (BBB). The brain capillary endothelial cells (BCECs) that compose the BBB express the receptors and transporters that enable this transport process. There is significant in vivo evidence to suggest that P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) restrict Aβ peptides entry into the brain, whereas the receptor for advanced glycation end-products (RAGE) seems to mediate apical-to-basolateral passage across the BBB. However, deciphering the molecular mechanisms underlying these in vivo processes requires further in vitro characterization. Using an in vitro BBB model and specific competition experiments against RAGE, we have observed a significant decrease in apical-to-basolateral (but not basolateral-to-apical) transport of Aβ1-40 and Aβ1-42 peptides through BCECs. This transport is a caveolae-dependent process and fits with the apical location of RAGE observed in confocal microscopy experiments. Inhibition of P-gp and BCRP using different inhibitors increases transport of Aβ peptides suggesting that these efflux pumps are involved in Aβ peptide transport at the BCECs level. Taken as a whole, these results demonstrate the involvement of the caveolae-dependent transcytosis of Aβ peptides through the BBB in a RAGE-mediated transport process, reinforcing the hypothesis whereby this receptor is a potential drug target in AD. PMID:20858979

  20. Pomegranate (Punicagranatum) juice decreases lipid peroxidation, but has no effect on plasma advanced glycated end-products in adults with type 2 diabetes: a randomized double-blind clinical trial

    PubMed Central

    Sohrab, Golbon; Angoorani, Pooneh; Tohidi, Maryam; Tabibi, Hadi; Kimiagar, Masoud; Nasrollahzadeh, Javad

    2015-01-01

    Introduction Diabetes mellitus characterized by hyperglycemia could increase oxidative stress and formation of advanced glycated end-products (AGEs), which contribute to diabetic complications. The purpose of this study was to assess the effect of pomegranate juice (PJ) containing natural antioxidant on lipid peroxidation and plasma AGEs in patients with type 2 diabetes (T2D). Materials and methods In a randomized, double-blind, placebo-controlled trial, 44 patients (age range 56±6.8 years), T2D were randomly assigned to one of two groups: group A (PJ, n=22) and group B (Placebo, n=22). At the baseline and the end of 12-week intervention, biochemical markers including fasting plasma glucose, insulin, oxidative stress, and AGE markers including carboxy methyl lysine (CML) and pentosidine were assayed. Results At baseline, there were no significant differences in plasma total antioxidant capacity (TAC) levels between the two groups, but malondialdehyde (MDA) decreased levels were significantly different (P<0.001). After 12 weeks of intervention, TAC increased (P<0.05) and MDA decreased (P<0.01) in the PJ group when compared with the placebo group. However, no significant differences were observed in plasma concentration of CML and pentosidine between the two groups. Conclusions The study showed that PJ decreases lipid peroxidation. Therefore, PJ consumption may delay onset of T2D complications related to oxidative stress. PMID:26355954

  1. Effects of candesartan cilexetil and amlodipine orotate on receptor for advanced glycation end products expression in the aortic wall of Otsuka Long-Evans Tokushima Fatty (OETFF) type 2 diabetic rats.

    PubMed

    Kang, Min-Kyu; Chung, Woo-Baek; Hong, Seul-Ki; Kim, Ok-Ran; Ihm, Sang-Hyun; Chang, Kiyuk; Seung, Ki-Bae

    2016-04-01

    The receptor for advanced glycation end products (RAGE) plays a key role in the development of vascular inflammation and acceleration of atherosclerosis in type 2 diabetes. We investigated the effect of candesartan cilexetil (CDRT) and amlodipine orotate (AMDP) on the expression of RAGE in the aortic walls of Otsuka Long-Evans Tokushima Fatty (OLETF) rats and AGE-treated endothelial cells. Twenty five-week-old OLETF rats were randomized to 8 week treatments consisting of CDRT (n = 8), AMDP (n = 8) or saline (control, n = 8). Immunohistochemical and dihydroethidine staining revealed reduced RAGE and reactive oxygen species (ROS) signals in rats treated with CDRT or AMDP compared with control rats. Both CDRT and AMDP suppressed the expression of p22phox and p47phox NADPH oxidase subunits. However, only CDRT significantly reduced expression of phosphorylated extracellular signal regulated kinase (pERK)1/2 in the aortic wall of OLETF rats. In addition, both drugs reduced RAGE expression and total and mitochondrial ROS production in the AGE-treated endothelial cells. Both ARBs and CCBs reduced RAGE expression in the aortic walls of OLETF rats, which was attributed to decreased ROS production through inhibition of NADPH oxidase. In addition, only CDRT reduced aortic expression of RAGE via suppression of the ERK1/2 pathway unlike AMDP. PMID:26960737

  2. Nifedipine, a calcium channel blocker, inhibits advanced glycation end product (AGE)-elicited mesangial cell damage by suppressing AGE receptor (RAGE) expression via peroxisome proliferator-activated receptor-gamma activation

    SciTech Connect

    Matsui, Takanori; Yamagishi, Sho-ichi; Takeuchi, Masayoshi; Ueda, Seiji; Fukami, Kei; Okuda, Seiya

    2009-07-24

    The interaction between advanced glycation end products (AGE) and their receptor RAGE mediates the progressive alteration in renal architecture and loss of renal function in diabetic nephropathy. Oxidative stress generation and inflammation also play a central role in diabetic nephropathy. This study investigated whether and how nifedipine, a calcium channel blocker (CCB), blocked the AGE-elicited mesangial cell damage in vitro. Nifedipine, but not amlodipine, a control CCB, down-regulated RAGE mRNA levels and subsequently reduced reactive oxygen species (ROS) generation in AGE-exposed mesangial cells. AGE increased mRNA levels of vascular cell adhesion molecule-1 (VCAM-1) and induced monocyte chemoattractant protein-1 (MCP-1) production in mesangial cells, both of which were prevented by the treatment with nifedipine, but not amlodipine. The beneficial effects of nifedipine on AGE-exposed mesangial cells were blocked by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}). Although nifedipine did not affect expression levels of PPAR-{gamma}, it increased the PPAR-{gamma} transcriptional activity in mesangial cells. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-inflammatory agent against AGE by suppressing RAGE expression in cultured mesangial cells via PPAR-{gamma} activation.

  3. Gram-Negative Flagella Glycosylation

    PubMed Central

    Merino, Susana; Tomás, Juan M.

    2014-01-01

    Protein glycosylation had been considered as an eccentricity of a few bacteria. However, through advances in analytical methods and genome sequencing, it is now established that bacteria possess both N-linked and O-linked glycosylation pathways. Both glycosylation pathways can modify multiple proteins, flagellins from Archaea and Eubacteria being one of these. Flagella O-glycosylation has been demonstrated in many polar flagellins from Gram-negative bacteria and in only the Gram-positive genera Clostridium and Listeria. Furthermore, O-glycosylation has also been demonstrated in a limited number of lateral flagellins. In this work, we revised the current advances in flagellar glycosylation from Gram-negative bacteria, focusing on the structural diversity of glycans, the O-linked pathway and the biological function of flagella glycosylation. PMID:24557579

  4. Effects of high glucose and advanced glycation end products on the expressions of sclerostin and RANKL as well as apoptosis in osteocyte-like MLO-Y4-A2 cells

    SciTech Connect

    Tanaka, Ken-ichiro Yamaguchi, Toru Kanazawa, Ippei Sugimoto, Toshitsugu

    2015-05-29

    In diabetes mellitus (DM), high glucose (HG) and advanced glycation end products (AGEs) are involved in bone quality deterioration. Osteocytes produce sclerostin and receptor activator of nuclear factor-kB ligand (RANKL) and regulate osteoblast and osteoclast function. However, whether HG or AGEs directly affect osteocytes and regulate sclerostin and RANKL production is unknown. Here, we examined the effects of HG, AGE2, and AGE3 on the expression of sclerostin and RANKL and on apoptosis in osteocyte-like MLO-Y4-A2 cells. Treatment of the cells with 22 mM glucose, 100 μg/mL either AGE2 or AGE3 significantly increased the expression of sclerostin protein and mRNA; however, both AGEs, but not glucose, significantly decreased the expression of RANKL protein and mRNA. Moreover, treatment of the cells with HG, AGE2, or AGE3 for 72 h induced significant apoptosis. These detrimental effects of HG, AGE2, and AGE3 on sclerostin and RANKL expressions and on apoptosis were antagonized by pretreatment of the cells with 10{sup −8} M human parathyroid hormone (PTH)-(1–34). Thus, HG and AGEs likely suppress bone formation by increasing sclerostin expression in osteocytes, whereas AGEs suppress bone resorption by decreasing RANKL expression. Together, these processes may cause low bone turnover in DM. In addition, HG and AGEs may cause cortical bone deterioration by inducing osteocyte apoptosis. PTH may effectively treat these pathological processes and improve osteocyte function. - Highlights: • AGEs are involved in bone quality deterioration in diabetes mellitus (DM). • AGEs increased sclerostin as well as apoptosis, and decreased RANKL in osteocytes. • The effects of AGEs on osteocyte function were antagonized by human PTH-(1–34). • AGEs may cause low bone turnover and cortical porosity in DM. • PTH may be effective in bone quality deterioration by improving osteocyte function.

  5. Correlation among soluble receptors for advanced glycation end-products, soluble vascular adhesion protein-1/semicarbazide-sensitive amine oxidase (sVAP-1) and cardiometabolic risk markers in apparently healthy adolescents: a cross-sectional study.

    PubMed

    Gurecká, Radana; Koborová, Ivana; Csongová, Melinda; Šebek, Jozef; Šebeková, Katarína

    2016-08-01

    In non-diabetics, low levels of soluble receptor for advanced glycations end products (sRAGE) associate with an increased risk of development of diabetes, cardiovascular afflictions, or death. The majority of studies in non-diabetics report an inverse relationship between measures of obesity, cardiometabolic risk factors and sRAGE and/or endogenous secretory RAGE (esRAGE) levels. To elucidate whether this inconsistency is related to the metabolically healthy obese phenotype, or a different impact of the risk factors in presence and absence of obesity, we analyzed data from 2206 apparently healthy adolescents (51 % girls) aged 15-to-19 years. The association of sRAGE levels with soluble vascular adhesion protein-1/semicarbazide sensitive amine oxidase (sVAP-1/SSAO) was also investigated. Centrally obese, including metabolically healthy, adolescents present significantly lower sRAGE and esRAGE, but not sVAP-1, levels in comparison with their lean counterparts. An increasing number of cardiometabolic risk factors did not associate with significant changes in sRAGE, esRAGE or sVAP-1 levels either in lean or in obese subjects. In multivariate analyses, WHtR, hsCRP, markers of glucose homeostasis, renal function, adiponectin, and sVAP-1 associated significantly with sRAGE and esRAGE. SVAP-1 correlated significantly with glycemia, adiponectin, hsCRP, and sRAGE. Thus, in adolescents, a decline in sRAGE and esRAGE precedes the development of metabolic syndrome. When combined, standard and non-standard cardiometabolic risk factors explain only minor proportion in a variability of sRAGE and esRAGE (8 %-11 %); or sVAP-1 (12 %-20 %). Elucidation of pathogenetic mechanisms underlying early decline in sRAGE and esRAGE levels in obese adolescents and their clinical impact with regard to future cardiometabolic health requires further studies. PMID:27300745

  6. Myricetin inhibits advanced glycation end product (AGE)-induced migration of retinal pericytes through phosphorylation of ERK1/2, FAK-1, and paxillin in vitro and in vivo.

    PubMed

    Kim, Young Sook; Kim, Junghyun; Kim, Ki Mo; Jung, Dong Ho; Choi, Sojin; Kim, Chan-Sik; Kim, Jin Sook

    2015-02-15

    Advanced glycation end products (AGE) have been implicated in the development of diabetic retinopathy. Characterization of the early stages of diabetic retinopathy is retinal pericytes loss, which is the result of pericytes migration. In this study, we investigated the pathological mechanisms of AGE on the migration of retinal pericytes and confirmed the inhibitory effect of myricetin on migration in vitro and in vivo. Migration assays of bovine retinal pericytes (BRP) were induced using AGE-BSA and phosphorylation of Src, ERK1/2, focal adhesion kinase (FAK-1) and paxillin were determined using immunoblot analysis. Sprague-Dawley rats (6 weeks old) were injected intravitreally with AGE-BSA and morphological and immunohistochemical analysis of p-FAK-1 and p-paxillin were performed in the rat retina. Immunoblot analysis and siRNA transfection were used to study the molecular mechanism of myricetin on BRP migration. AGE-BSA increased BRP migration in a dose-dependent manner via receptor for AGEs (RAGE)-dependent activation of the Src kinase-ERK1/2 pathway. AGE-BSA-induced migration was inhibited by an ERK1/2 specific inhibitor (PD98059), but not by p38 and Jun N-terminal kinase inhibitors. AGE-BSA increased FAK-1 and paxillin phosphorylation in a dose- and time-dependent manner. These increases were attenuated by PD98059 and ERK1/2 siRNA. Phosphorylation of FAK-1 and paxillin was increased in response to AGE-BSA-induced migration of rat retinal pericytes. Myricetin strongly inhibited ERK1/2 phosphorylation and significantly suppressed pericytes migration in AGE-BSA-injected rats. Our results demonstrate that AGE-BSA participated in the pathophysiology of retinal pericytes migration likely through the RAGE-Src-ERK1/2-FAK-1-paxillin signaling pathway. Furthermore, myricetin suppressed phosphorylation of ERK 1/2-FAK-1-paxillin and inhibited pericytes migration. PMID:25450667

  7. Role of N–epsilon- carboxy methyl lysine, advanced glycation end products and reactive oxygen species for the development of nonproliferative and proliferative retinopathy in type 2 diabetes mellitus

    PubMed Central

    Choudhuri, Subhadip; Dutta, Deep; Sen, Aditi; Chowdhury, Imran Hussain; Mitra, Bhaskar; Mondal, Lakshmi Kanta; Saha, Avijit; Bhadhuri, Gautam

    2013-01-01

    Purpose The aim of the present study was to evaluate the collective role of N-epsilon–carboxy methyl lysine (Nε-CML), advanced glycation end-products (AGEs), and reactive oxygen species (ROS) for the development of retinopathy among type 2 diabetic subjects. Methods Seventy type 2 diabetic subjects with nonproliferative diabetic retinopathy (NPDR), 105 subjects with proliferative diabetic retinopathy (PDR), and 102 patients with diabetes but without retinopathy (DNR) were enrolled in this study. In addition, 95 normal individuals without diabetes were enrolled as healthy controls in this study. Serum and vitreous Nε-CML and AGEs were measured by enzyme-linked immunosorbent assay. The peripheral blood mononuclear cell (PBMC) ROS level was measured by flow cytometric analysis. Serum and PBMC total thiols were measured by spectrophotometry. Results Serum AGEs and Nε-CML levels were significantly elevated in subjects with PDR (p<0.0001) and NPDR (p=0.0297 and p<0.0001, respectively) compared to DNR subjects. Further vitreous AGEs and Nε-CML levels were found to be significantly high among PDR subjects compared to the control group (p<0.0001). PBMC ROS production was found to be strikingly high among NPDR (p<0.0001) and PDR (p<0.0001) subjects as compared to the DNR group. Serum and PBMC total thiol levels were remarkably decreased in NPDR (p<0.0001 and p=0.0043, respectively) and PDR (p=0.0108 and p=0.0332 respectively) subjects than those were considered as DNR. Conclusions Our findings suggest that Nε-CML and ROS are the key modulators for the development of nonproliferative retinopathy among poorly controlled type 2 diabetic subjects. Furthermore, AGEs under persistent oxidative stress and the deprived antioxidant state might instigate the pathogenic process of retinopathy from the nonproliferative to the proliferative state. PMID:23378723

  8. Effects of high glucose and advanced glycation end products on the expressions of sclerostin and RANKL as well as apoptosis in osteocyte-like MLO-Y4-A2 cells.

    PubMed

    Tanaka, Ken-ichiro; Yamaguchi, Toru; Kanazawa, Ippei; Sugimoto, Toshitsugu

    2015-05-29

    In diabetes mellitus (DM), high glucose (HG) and advanced glycation end products (AGEs) are involved in bone quality deterioration. Osteocytes produce sclerostin and receptor activator of nuclear factor-кB ligand (RANKL) and regulate osteoblast and osteoclast function. However, whether HG or AGEs directly affect osteocytes and regulate sclerostin and RANKL production is unknown. Here, we examined the effects of HG, AGE2, and AGE3 on the expression of sclerostin and RANKL and on apoptosis in osteocyte-like MLO-Y4-A2 cells. Treatment of the cells with 22 mM glucose, 100 μg/mL either AGE2 or AGE3 significantly increased the expression of sclerostin protein and mRNA; however, both AGEs, but not glucose, significantly decreased the expression of RANKL protein and mRNA. Moreover, treatment of the cells with HG, AGE2, or AGE3 for 72 h induced significant apoptosis. These detrimental effects of HG, AGE2, and AGE3 on sclerostin and RANKL expressions and on apoptosis were antagonized by pretreatment of the cells with 10(-8) M human parathyroid hormone (PTH)-(1-34). Thus, HG and AGEs likely suppress bone formation by increasing sclerostin expression in osteocytes, whereas AGEs suppress bone resorption by decreasing RANKL expression. Together, these processes may cause low bone turnover in DM. In addition, HG and AGEs may cause cortical bone deterioration by inducing osteocyte apoptosis. PTH may effectively treat these pathological processes and improve osteocyte function. PMID:25721666

  9. Generation of Soluble Advanced Glycation End Products Receptor (sRAGE)-Binding Ligands during Extensive Heat Treatment of Whey Protein/Lactose Mixtures Is Dependent on Glycation and Aggregation.

    PubMed

    Liu, Fahui; Teodorowicz, Małgorzata; Wichers, Harry J; van Boekel, Martinus A J S; Hettinga, Kasper A

    2016-08-24

    Heating of protein- and sugar-containing materials is considered the primary factor affecting the formation of advanced glycation end products (AGEs). This study aimed to investigate the influence of heating conditions, digestion, and aggregation on the binding capacity of AGEs to the soluble AGE receptor (sRAGE). Samples consisting of mixtures of whey protein and lactose were heated at 130 °C. An in vitro infant digestion model was used to study the influence of heat treatment on the digestibility of whey proteins. The amount of sRAGE-binding ligands before and after digestion was measured by an ELISA-based sRAGE-binding assay. Water activity did not significantly affect the extent of digestibility of whey proteins dry heated at pH 5 (ranging from 3.3 ± 0.2 to 3.6 ± 0.1% for gastric digestion and from 53.5 ± 1.5 to 64.7 ± 1.1% for duodenal digestion), but there were differences in cleavage patterns of peptides among the samples heated at different pH values. Formation of sRAGE-binding ligands depended on the formation of aggregates and was limited in the samples heated at pH 5. Moreover, the sRAGE-binding activity of digested sample was changed by protease degradation and correlated with the digestibility of samples. In conclusion, generation of sRAGE-binding ligands during extensive heat treatment of whey protein/lactose mixtures is limited in acidic heating condition and dependent on glycation and aggregation. PMID:27460534

  10. Differential effects of α-tocopherol and N-acetyl-cysteine on advanced glycation end product-induced oxidative damage and neurite degeneration in SH-SY5Y cells.

    PubMed

    Pazdro, Robert; Burgess, John R

    2012-04-01

    Advanced glycation end products (AGEs) result from non-enzymatic glycation of proteins and cause cellular oxidative stress in a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent manner. Due to these effects, AGEs are implicated as a causal factor in diabetic complications. Several antioxidants, including vitamin E, improve cell viability and diminish markers of oxidative damage in cells exposed to AGEs. However, vitamin E has been studied in cell culture systems with primary focus on apoptosis and lipid peroxidation, while its influences on AGE-induced protein and DNA oxidation, intracellular antioxidant status and cell morphology remain largely unknown. Here, we verify the suppression of AGE-induced cell death and lipid peroxidation by 200μM α-tocopherol in SH-SY5Y cells. We report the partial inhibition of DNA oxidation and a decrease in protein carbonyl formation by α-tocopherol with no effects on intracellular GSH concentrations. We observed that 2mM N-acetyl cysteine (NAC) also had a suppressive effect on DNA and protein oxidation, but unlike α-tocopherol, it caused a marked increase in intracellular GSH. Finally, we compared the ability of both antioxidants to maintain neurites in SH-SY5Y cells and found that α-tocopherol had no effect on neurite loss due to AGEs, while NAC fully maintained cell morphology. Thus, while α-tocopherol suppressed AGE-induced macromolecule damage, it was ineffective against neurite degeneration. These results may implicate thiol oxidation and maintenance as a major regulator of neurite degeneration in this model. PMID:22261284

  11. Presence of dopa and amino acid hydroperoxides in proteins modified with advanced glycation end products (AGEs): amino acid oxidation products as a possible source of oxidative stress induced by AGE proteins.

    PubMed

    Fu, S; Fu, M X; Baynes, J W; Thorpe, S R; Dean, R T

    1998-02-15

    Glycation and subsequent Maillard or browning reactions of glycated proteins, leading to the formation of advanced glycation end products (AGEs), are involved in the chemical modification of proteins during normal aging and have been implicated in the pathogenesis of diabetic complications. Oxidative conditions accelerate the browning of proteins by glucose, and AGE proteins also induce oxidative stress responses in cells bearing AGE receptors. These observations have led to the hypothesis that glycation-induced pathology results from a cycle of oxidative stress, increased chemical modification of proteins via the Maillard reaction, and further AGE-dependent oxidative stress. Here we show that the preparation of AGE-collagen by incubation with glucose under oxidative conditions in vitro leads not only to glycation and formation of the glycoxidation product Nepsilon-(carboxymethyl)lysine (CML), but also to the formation of amino acid oxidation products on protein, including m-tyrosine, dityrosine, dopa, and valine and leucine hydroperoxides. The formation of both CML and amino acid oxidation products was prevented by anaerobic, anti-oxidative conditions. Amino acid oxidation products were also formed when glycated collagen, prepared under anti-oxidative conditions, was allowed to incubate under aerobic conditions that led to the formation of CML. These experiments demonstrate that amino acid oxidation products are formed in proteins during glycoxidation reactions and suggest that reactive oxygen species formed by redox cycling of dopa or by the metal-catalysed decomposition of amino acid hydroperoxides, rather than by redox activity or reactive oxygen production by AGEs on protein, might contribute to the induction of oxidative stress by AGE proteins. PMID:9461515

  12. Advanced glycation end product 3 (AGE3) suppresses the mineralization of mouse stromal ST2 cells and human mesenchymal stem cells by increasing TGF-β expression and secretion.

    PubMed

    Notsu, Masakazu; Yamaguchi, Toru; Okazaki, Kyoko; Tanaka, Ken-ichiro; Ogawa, Noriko; Kanazawa, Ippei; Sugimoto, Toshitsugu

    2014-07-01

    In diabetic patients, advanced glycation end products (AGEs) cause bone fragility because of deterioration of bone quality. We previously showed that AGEs suppressed the mineralization of mouse stromal ST2 cells. TGF-β is abundant in bone, and enhancement of its signal causes bone quality deterioration. However, whether TGF-β signaling is involved in the AGE-induced suppression of mineralization during the osteoblast lineage remains unknown. We therefore examined the roles of TGF-β in the AGE-induced suppression of mineralization of ST2 cells and human mesenchymal stem cells. AGE3 significantly (P < .001) inhibited mineralization in both cell types, whereas transfection with small interfering RNA for the receptor for AGEs (RAGEs) significantly (P < .05) recovered this process in ST2 cells. AGE3 increased (P < .001) the expression of TGF-β mRNA and protein, which was partially antagonized by transfection with RAGE small interfering RNA. Treatment with a TGF-β type I receptor kinase inhibitor, SD208, recovered AGE3-induced decreases in osterix (P < .001) and osteocalcin (P < .05) and antagonized the AGE3-induced increase in Runx2 mRNA expression in ST2 cells (P < .001). Moreover, SD208 completely and dose dependently rescued AGE3-induced suppression of mineralization in both cell types. In contrast, SD208 intensified AGE3-induced suppression of cell proliferation as well as AGE3-induced apoptosis in proliferating ST2 cells. These findings indicate that, after cells become confluent, AGE3 partially inhibits the differentiation and mineralization of osteoblastic cells by binding to RAGE and increasing TGF-β expression and secretion. They also suggest that TGF-β adversely affects bone quality not only in primary osteoporosis but also in diabetes-related bone disorder. PMID:24758301

  13. Structural insights into the binding of the human receptor for advanced glycation end products (RAGE) by S100B, as revealed by an S100B–RAGE-derived peptide complex

    PubMed Central

    Jensen, Jaime L.; Indurthi, Venkata S. K.; Neau, David B.; Vetter, Stefan W.; Colbert, Christopher L.

    2015-01-01

    S100B is a damage-associated molecular pattern protein that, when released into the extracellular milieu, triggers initiation of the inflammatory response through the receptor for advanced glycation end products (RAGE). Recognition of S100B is accomplished via the amino-terminal variable immunoglobulin domain (V-domain) of RAGE. To gain insights into this interaction, a complex between S100B and a 15-amino-acid peptide derived from residues 54–68 of the V-domain was crystallized. The X-ray crystal structure was solved to 2.55 Å resolution. There are two dimers of S100B and one peptide in the asymmetric unit. The binding interface of this peptide is compared with that found in the complex between S100B and the 12-amino-acid CapZ-derived peptide TRTK-12. This comparison reveals that although the peptides adopt completely different backbone structures, the residues buried at the interface interact with S100B in similar regions to form stable complexes. The binding affinities of S100B for the intact wild-type V-domain and a W61A V-domain mutant were determined to be 2.7 ± 0.5 and 1.3 ± 0.7 µM, respectively, using fluorescence titration experiments. These observations lead to a model whereby conformational flexibility in the RAGE receptor allows the adoption of a binding conformation for interaction with the stable hydrophobic groove on the surface of S100B. PMID:25945582

  14. Barley malt increases hindgut and portal butyric acid, modulates gene expression of gut tight junction proteins and Toll-like receptors in rats fed high-fat diets, but high advanced glycation end-products partially attenuate the effects.

    PubMed

    Zhong, Yadong; Teixeira, Cristina; Marungruang, Nittaya; Sae-Lim, Watina; Tareke, Eden; Andersson, Roger; Fåk, Frida; Nyman, Margareta

    2015-09-01

    Barley malt, a product of controlled germination, has been shown to produce high levels of butyric acid in the cecum and portal serum of rats and may therefore have anti-inflammatory effects. The aim of the study was to investigate how four barley malts, caramelized and colored malts, 50-malt and 350-malt, differing in functional characteristics concerning beta-glucan content and color, affect short-chain fatty acids (SCFA), barrier function and inflammation in the hindgut of rats fed high-fat diets. Male Wistar rats were given malt-supplemented high-fat diets for four weeks. Low and high-fat diets containing microcrystalline cellulose were incorporated as controls. All diets contained 70 g kg(-1) dietary fiber. The malt-fed groups were found to have had induced higher amounts of butyric and propionic acids in the hindgut and portal serum compared with controls, while cecal succinic acid only increased to a small extent. Fat increased the mRNA expression of tight junction proteins and Toll-like receptors (TLR) in the small intestine and distal colon of the rats, as well as the concentration of some amino acids in the portal plasma, but malt seemed to counteract these adverse effects to some extent. However, the high content of advanced glycation end-products (AGE) in caramelized malt tended to prohibit the positive effects on occludin in the small intestine and plasma amino acids seen with the other malt products. In conclusion, malting seems to be an interesting process for producing foods with positive health effects, but part of these effects may be destroyed if the malt contains a high content of AGE. PMID:26227569

  15. Receptor for Advanced Glycation End Products (RAGE) Functions as Receptor for Specific Sulfated Glycosaminoglycans, and Anti-RAGE Antibody or Sulfated Glycosaminoglycans Delivered in Vivo Inhibit Pulmonary Metastasis of Tumor Cells*

    PubMed Central

    Mizumoto, Shuji; Takahashi, Jun; Sugahara, Kazuyuki

    2012-01-01

    Altered expression of chondroitin sulfate (CS) and heparan sulfate (HS) at the surfaces of tumor cells plays a key role in malignant transformation and tumor metastasis. Previously we demonstrated that a Lewis lung carcinoma (LLC)-derived tumor cell line with high metastatic potential had a higher proportion of E-disaccharide units, GlcUA-GalNAc(4,6-O-disulfate), in CS chains than low metastatic LLC cells and that such CS chains are involved in the metastatic process. The metastasis was markedly inhibited by the pre-administration of CS-E from squid cartilage rich in E units or by preincubation with a phage display antibody specific for CS-E. However, the molecular mechanism of the inhibition remains to be investigated. In this study the receptor molecule for CS chains containing E-disaccharides expressed on LLC cells was revealed to be receptor for advanced glycation end products (RAGE), which is a member of the immunoglobulin superfamily predominantly expressed in the lung. Interestingly, RAGE bound strongly to not only E-disaccharide, but also HS-expressing LLC cells. Furthermore, the colonization of the lungs by LLC cells was effectively inhibited by the blocking of CS or HS chains at the tumor cell surface with an anti-RAGE antibody through intravenous injections in a dose-dependent manner. These results provide the clear evidence that RAGE is at least one of the critical receptors for CS and HS chains expressed at the tumor cell surface and involved in experimental lung metastasis and that CS/HS and RAGE are potential molecular targets in the treatment of pulmonary metastasis. PMID:22493510

  16. Dietary Advanced Glycation End Products Consumption as a Direct Modulator of Insulin Sensitivity in Overweight Humans: A Study Protocol for a Double-Blind, Randomized, Two Period Cross-Over Trial

    PubMed Central

    de Courten, Maximilian PJ; Schalkwijk, Casper G; Walker, Karen Z; Forbes, Josephine

    2015-01-01

    Background Advanced glycation end products (AGEs) are formed during the processing, storage, and cooking of foods. As part of a western diet, AGEs are consumed in excess and impair glucose metabolism in patients with type 2 diabetes. In the absence of diabetes, AGE-mediated decreases in insulin sensitivity and signaling have been postulated. However, randomized studies to test this relationship in humans are limited. Objective The primary aim of this trial is to determine whether dietary consumption of AGEs will decrease insulin sensitivity in healthy overweight adults. A secondary aim is to determine the effects of dietary AGEs on insulin secretion, circulating soluble receptor for AGEs (sRAGE), and inflammation markers. Methods Overweight, but otherwise healthy, non-diabetic adults (N=20) aged 18-50 years old will complete a randomized cross-over design intervention study alternating low and high (4-fold increase) AGE diets (2-week duration). At baseline, participants will undergo a medical review including an intravenous glucose tolerance test (IVGTT), a hyperinsulinemic-euglycemic clamp, and anthropometric measures and questionnaires assessing diet, physical activity, and general wellness. Each test diet will be followed for 14 days, followed by a 4-week washout period before commencement of the second alternate dietary period. Energy, macronutrient, and AGE intake will be calculated for each dietary period. Additionally, the AGE content of foods used in the study will be measured by ultra performance liquid chromatography mass spectrometry. All measurements will be repeated at the beginning and end of each dietary period. Primary and secondary outcomes will be expressed as a change over the dietary period for insulin sensitivity, secretion, anthropometric parameters, sRAGE, and inflammation markers and compared by paired t test and analysis of variance (ANOVA). Results The study will be completed in early 2016. Conclusion The proposed trial will provide much

  17. Advanced glycation end products upregulate lysyl oxidase and endothelin-1 in human aortic endothelial cells via parallel activation of ERK1/2-NF-κB and JNK-AP-1 signaling pathways.

    PubMed

    Adamopoulos, Christos; Piperi, Christina; Gargalionis, Antonios N; Dalagiorgou, Georgia; Spilioti, Eliana; Korkolopoulou, Penelope; Diamanti-Kandarakis, Evanthia; Papavassiliou, Athanasios G

    2016-04-01

    Endothelial dysfunction involves deregulation of the key extracellular matrix (ECM) enzyme lysyl oxidase (LOX) and the vasoconstrictor protein, endothelin-1 (ET-1), whose gene expression can be modulated by the transcriptional activators nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1). Advanced glycation end products (AGEs) present an aggravating factor of endothelial dysfunction which upon engagement to their receptor RAGE induce upregulation of mitogen-activated protein kinases (MAPKs), leading to NF-κB and AP-1 potentiation. We hypothesized that AGEs could induce NF-κΒ- and AP-1-dependent regulation of LOX and ET-1 expression via the AGE/RAGE/MAPK signaling axis. Western blot, real-time qRT-PCR, FACS analysis and electrophoretic mobility-shift assays were employed in human aortic endothelial cells (HAECs) following treatment with AGE-bovine serum albumin (AGE-BSA) to investigate the signaling pathway towards this hypothesis. Furthermore, immunohistochemical analysis of AGEs, RAGE, LOX and ET-1 expression was conducted in aortic endothelium of a rat experimental model exposed to high- or low-AGE content diet. HAECs exposed to AGE-BSA for various time points exhibited upregulation of LOX and ET-1 mRNA levels in a dose- and time-dependent manner. Exposure of HAECs to AGE-BSA also showed specific elevation of phospho(p)-ERK1/2 and p-JNK levels in a dose- and time-dependent fashion. AGE administration significantly increased NF-κΒ- and AP-1-binding activity to both LOX and ET-1 cognate promoter regions. Moreover, LOX and ET-1 overexpression in rat aortic endothelium upon high-AGE content diet confirmed the functional interrelation of these molecules. Our findings demonstrate that AGEs trigger NF-κΒ- and AP-1-mediated upregulation of LOX and ET-1 via the AGE/RAGE/MAPK signaling cascade in human endothelial cells, thus contributing to distorted endothelial homeostasis by impairing endothelial barrier function, altering ECM biomechanical properties

  18. Advanced glycation end products (AGEs), but not high glucose, inhibit the osteoblastic differentiation of mouse stromal ST2 cells through the suppression of osterix expression, and inhibit cell growth and increasing cell apoptosis.

    PubMed

    Okazaki, Kyoko; Yamaguchi, Toru; Tanaka, Ken-Ichiro; Notsu, Masakazu; Ogawa, Noriko; Yano, Shozo; Sugimoto, Toshitsugu

    2012-10-01

    Diabetes mellitus is known to be associated with osteoporotic fractures through a decrease in osteoblastic bone formation rather than an increase in osteoclastic bone resorption. However, its precise mechanism is unknown, and we examined whether or not high glucose or advanced glycation end products (AGEs), which play key roles in the pathogenesis and complications of diabetes, would affect the osteoblastic differentiation, growth, and apoptosis of mouse stromal ST2 cells. Ten to 200 μg/mL AGE2 or AGE3 alone dose-dependently inhibited the mineralization. AGE2 or AGE3 alone (200 μg/mL) significantly inhibited alkaline phosphatase (ALP) activities as well as the mineralization of the cells (p < 0.01). In contrast, 22 mM glucose alone or in combination with 200 μg/mL AGE2 or AGE3 did not affect these cellular phenotypes. Real-time PCR showed that AGE2 or AGE3 alone (200 μg/mL) significantly decreased mRNA expressions of osteocalcin as well as osterix on day 14 (p < 0.01). Western blot analysis showed that AGE2 or AGE3 alone (200 μg/mL) also decreased the levels of Runx2 and osterix protein expressions on days 7 and 14. AGE2 or AGE3 significantly suppressed cell growth and increased apoptotic cell death in time- and dose-dependent manners (p < 0.01). Moreover, AGE3 alone (200 μg/mL) significantly increased mRNA expression of the receptor for AGEs (RAGE) on days 2 and 3 (p < 0.01). These results suggest that AGE2 and AGE3, but not high glucose, may inhibit the osteoblastic differentiation of stromal cells by decreasing osterix expression and partly by increasing RAGE expression, as well as inhibiting cell growth and increasing cell apoptosis. PMID:22903508

  19. Pinocembrin protects against β-amyloid-induced toxicity in neurons through inhibiting receptor for advanced glycation end products (RAGE)-independent signaling pathways and regulating mitochondrion-mediated apoptosis

    PubMed Central

    2012-01-01

    Background It is known that amyloid-β peptide (Aβ) plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). Interaction between Aβ and the receptor for advanced glycation end products (RAGE) has been implicated in neuronal degeneration associated with this disease. Pinocembrin, a flavonoid abundant in propolis, has been reported to possess numerous biological activities beneficial to health. Our previous studies have demonstrated that pinocembrin has neuroprotective effects on ischemic and vascular dementia in animal models. It has been approved by the State Food and Drug Administration of China for clinical use in stroke patients. Against this background, we investigated the effects of pinocembrin on cognitive function and neuronal protection against Aβ-induced toxicity and explored its potential mechanism. Methods Mice received an intracerebroventricular fusion of Aβ25-35. Pinocembrin was administrated orally at 20 mg/kg/day and 40 mg/kg/day for 8 days. Behavioral performance, cerebral cortex neuropil ultrastructure, neuronal degeneration and RAGE expression were assessed. Further, a RAGE-overexpressing cell model and an AD cell model were used for investigating the mechanisms of pinocembrin. The mechanisms underlying the efficacy of pinocembrin were conducted on target action, mitochondrial function and potential signal transduction using fluorescence-based multiparametric technologies on a high-content analysis platform. Results Our results showed that oral administration of pinocembrin improved cognitive function, preserved the ultrastructural neuropil and decreased neurodegeneration of the cerebral cortex in Aβ25-35-treated mice. Pinocembrin did not have a significant effect on inhibiting Aβ1-42 production and scavenging intracellular reactive oxygen species (ROS). However, pinocembrin significantly inhibited the upregulation of RAGE transcripts and protein expression both in vivo and in vitro, and also markedly depressed the activation of

  20. [Analysis of the impact of heparin on the affinity of high mobility group box-1 protein and the receptor of advanced glycation end products by surface plasmon resonance technology].

    PubMed

    Ling, Yan; Wang, Chun-You; Yang, Zhi-Yong

    2009-11-01

    To investigate the affinity constants of heparin with high mobility group protein 1(HMGB1) and HMGB1 with the receptor of advanced glycation end products (RAGE) and to analyze the impact of heparin on the affinity of HMGB1 and RAGE, the standard BIAcore amine coupling chemistry protocol using EDC and NHS was employed for immobilizing. Surface plasmon resonance biosensor technology was used to detect the affinity constants of heparin/HMGB1, HMGB1/RAGE and heparin/ RAGE. Binding analysis was used to investigate the impact of heparin on the affinity of HMGB1 and RAGE. After the immobilization, 9 000 and 5 000 RU rise of HMGB1 and RAGE respectively were obtained. These meant that the immobilized values of HMGB1 and RAGE were about 9 and 5 ng x mm(-2) respectively. The kinetic constants were k(a) = 1.78 x 10(5) L x mol(-1) x s(-1), kd = 8.02 x 10(-4) s(-1), and the affinity constants were KA = 2.22 x 10(8) L x mol(-1), the equilibrium dissociation constant K(D) = 4.5 x 10(-9) mol x L(-1) for heparin and HMGB1; while the kinetic constants were k(a) = 1.85 x 10(3) L x mol(-1) x s(-1), k(d) = 1.81 x 10(-4) s(-1), K(A) = 1.02 x 10(7) L x mol(-1), K(D) = 9.77 x 10(-8) mol x L(-1) for HMGB1 and RAGE; there was very low affinity of heparin with RAGE. The highest concentration of 10 000 u x L(-1) of heparin in this experiment did not reach the saturation with HMGB1. After 50 mg x L(-1) of HMGB1 was mixed with heparin of 50, 100, 1 000, 10 000 u x L(-1), the combining amount of HMGB1 and RAGE declined from 100 to 50 RU. But there were no significant differences between different concentrations of heparin. It was concluded that heparin can combine with HMGB1 and affect the affinity of HMGB1/RAGE. In addition, this impact was not in a dose-dependent manner. PMID:20101991

  1. Advanced glycosylation endproducts block the antiproliferative effect of nitric oxide. Role in the vascular and renal complications of diabetes mellitus.

    PubMed

    Hogan, M; Cerami, A; Bucala, R

    1992-09-01

    Advanced glycosylation endproducts (AGEs) accumulate on long-lived tissue proteins such as basement membrane collagen and have been implicated in many of the long-term complications of diabetes mellitus. These products originate from glucose-derived Schiff base and Amadori products but undergo a series of complex rearrangement reactions to form ultimately protein-bound, fluorescent heterocycles. AGEs can react with and chemically inactivate nitric oxide (NO), a potent endothelial cell-derived vasodilator and antiproliferative factor. Since mesenchymal cell proliferation is an early and characteristic lesion of diabetic vasculopathy and glomerulopathy, we investigated the possibility that collagen-bound AGEs functionally inactivate the antiproliferative effect of NO. In model cell culture systems, AGEs were found to block the cytostatic effect of NO on aortic smooth muscle and renal mesangial cells. The inactivation of endothelial cell-derived NO by basement membrane AGEs may represent a common pathway in the development of the accelerated vascular and renal disease that accompany long-term diabetes mellitus. PMID:1522220

  2. Glycosylation Engineering of Glycoproteins

    NASA Astrophysics Data System (ADS)

    Sadamoto, Reiko; Nishimura, Shin-Ichiro

    Naturally occurring glycosylation of glycoproteins varies in glycosylation site and in the number and structure of glycans. The engineering of well-defined glycoproteins is an important technology for the preparation of pharmaceutically relevant glycoproteins and in the study of the relationship between glycans and proteins on a structure-function level. In pharmaceutical applications of glycoproteins, the presence of terminal sialic acids on glycans is particularly important for the in vivo circulatory half life, since sialic acid-terminated glycans are not recognized by asialoglycoprotein receptors. Therefore, there have been a number of attempts to control or modify cellular metabolism toward the expression of glycoproteins with glycosylation profiles similar to that of human glycoproteins. In this chapter, recent methods for glycoprotein engineering in various cell culture systems (mammalian cells, plant, yeast, and E. coli) and advances in the chemical approach to glycoprotein formation are described.

  3. Synthesis and biological activity of 4-aryl-3-benzoyl-5-phenylspiro[pyrrolidine-2.3'-indolin]-2'-one derivatives as novel potent inhibitors of advanced glycation end product.

    PubMed

    Kaur, Anjandeep; Singh, Baldev; Vyas, Bhawna; Silakari, Om

    2014-05-22

    Diabetic complications and their detrimental effects caused by sugar derived substances, have been the serious issue for the last few years and have yet not been fully combated. The key point of the present study is to synthesize some newer chemical entities which can eradicate such ailments to the maximum possible extent. So with this aim synthesis of some biologically interesting spiro-indolone-pyrrolidine derivatives was accomplished by 1,3-dipolar cycloaddition reaction of azomethine ylide 6 generated in situ from isatin and benzyl amine with the substituted α,β-unsaturated carbonyl compounds 3 as dipolarophile, leading to the formation of new 4-aryl-3-benzoyl-5-phenylspiro[pyrrolidine-2.3'-indolin]-2'-one derivatives 7 stereoselectively in excellent yields. The synthesized compounds have been screened for their advanced glycation end (AGE) product formation inhibitory activity on the basis of their ability to inhibit the formation of AGEs in the bovine serum albumin (BSA)-glucose assay and have been found to exhibit significant activity against AGE formation. PMID:24747065

  4. Bacterial Protein N-Glycosylation: New Perspectives and Applications*

    PubMed Central

    Nothaft, Harald; Szymanski, Christine M.

    2013-01-01

    Protein glycosylation is widespread throughout all three domains of life. Bacterial protein N-glycosylation and its application to engineering recombinant glycoproteins continue to be actively studied. Here, we focus on advances made in the last 2 years, including the characterization of novel bacterial N-glycosylation pathways, examination of pathway enzymes and evolution, biological roles of protein modification in the native host, and exploitation of the N-glycosylation pathways to create novel vaccines and diagnostics. PMID:23329827

  5. Glycosylated haemoglobin: measurement and clinical use.

    PubMed Central

    Peacock, I

    1984-01-01

    The discovery, biochemistry, laboratory determination, and clinical application of glycosylated haemoglobins are reviewed. Sources of error are discussed in detail. No single assay method is suitable for all purposes, and in the foreseeable future generally acceptable standards and reference ranges are unlikely to be agreed. Each laboratory must establish its own. Nevertheless, the development of glycosylated haemoglobin assays is an important advance. They offer the best available means of assessing diabetic control. PMID:6381544

  6. A Propos of Glycosyl Cations and the Mechanism of Chemical Glycosylation; the Current State of the Art

    PubMed Central

    Bohé, Luis

    2014-01-01

    An overview of recent advances in glycosylation with particular emphasis on mechanism is presented. The mounting evidence for both the existence of glycosyl oxocarbenium ions as fleeting intermediates in some reactions, and the crucial role of the associated in counter ion in others is discussed. The extremes of the SN1 and SN2 manifolds for the glycosylation reaction are bridged by a continuum of mechanisms in which it appears likely that most examples are located. PMID:25108484

  7. Human plasma protein N-glycosylation.

    PubMed

    Clerc, Florent; Reiding, Karli R; Jansen, Bas C; Kammeijer, Guinevere S M; Bondt, Albert; Wuhrer, Manfred

    2016-06-01

    Glycosylation is the most abundant and complex protein modification, and can have a profound structural and functional effect on the conjugate. The oligosaccharide fraction is recognized to be involved in multiple biological processes, and to affect proteins physical properties, and has consequentially been labeled a critical quality attribute of biopharmaceuticals. Additionally, due to recent advances in analytical methods and analysis software, glycosylation is targeted in the search for disease biomarkers for early diagnosis and patient stratification. Biofluids such as saliva, serum or plasma are of great use in this regard, as they are easily accessible and can provide relevant glycosylation information. Thus, as the assessment of protein glycosylation is becoming a major element in clinical and biopharmaceutical research, this review aims to convey the current state of knowledge on the N-glycosylation of the major plasma glycoproteins alpha-1-acid glycoprotein, alpha-1-antitrypsin, alpha-1B-glycoprotein, alpha-2-HS-glycoprotein, alpha-2-macroglobulin, antithrombin-III, apolipoprotein B-100, apolipoprotein D, apolipoprotein F, beta-2-glycoprotein 1, ceruloplasmin, fibrinogen, immunoglobulin (Ig) A, IgG, IgM, haptoglobin, hemopexin, histidine-rich glycoprotein, kininogen-1, serotransferrin, vitronectin, and zinc-alpha-2-glycoprotein. In addition, the less abundant immunoglobulins D and E are included because of their major relevance in immunology and biopharmaceutical research. Where available, the glycosylation is described in a site-specific manner. In the discussion, we put the glycosylation of individual proteins into perspective and speculate how the individual proteins may contribute to a total plasma N-glycosylation profile determined at the released glycan level. PMID:26555091

  8. Adipose stem cells' antagonism in glycosylation of D-galactose-induced skin aging of nude mice and its skin recovery function.

    PubMed

    Wang, Haiying; Wei, Shuyue; Xue, Xinxin; You, Yuntian; Ma, Qiang

    2016-09-01

    This study aims to discuss adipose stem cells' (ASCs) antagonism in glycosylation of D-galactose-induced skin aging of nude mice and its skin recovery function; the study also aims to explore a new mechanism of anti-aging to provide clinical anti-aging therapy with new thoughts and methods. We selected 40 healthy specific pathogen-free (SPF) nude mice and divided them randomly into four groups which were: blank control group; D-galactose + phosphate buffer saline (PBS) group; D-galactose + ASCs treatment group; and D-galactose + aminoguanidine (AG) group. Results showed that the superoxide dismutase (SOD) level of mice in the D-galactose-induced model group (87.15 ± 4.95 U/g) decreased significantly compared with that of control group (146.21 ± 4.76 U/g), while malonaldehyde (MDA) level of mice in D-galactose induced model group (11.12 ± 2.08 nmol/mg) increased significantly compared with that of control group (5.46 ± 2.05 nmol/mg) (P <0.05); thus D-galactose induced sub-acutely aging mice models were duplicated successfully. Results also indicated that transplantation of ASCs could reverse expression of aging-related biomarkers such as MDA, SOD, and advanced glycosylation end products (AGEs); hematoxylin and eosin (HE) staining showed that thickness of the dermis layer as well as the collagen content of mice in the D-galactose-induced model group increased significantly after ASC transplantation compared with that of control group. In addition, immunohistochemical assay showed that expression quantity of CD31 and vascular endothelial growth factor (VEGF) of mice in the D-galactose-induced model group increased significantly after ASC transplantation compared with that of control group. In conclusion, ASCs can trace cell distribution successfully through bioluminescence, and they survive for a short time in the skin after transplantation, which provides a basis for the application of ASC transplantation in clinical practices. Moreover, ASCs can control

  9. 48 CFR 252.225-7022 - Trade agreements certificate-inclusion of Iraqi end products.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... certificate-inclusion of Iraqi end products. 252.225-7022 Section 252.225-7022 Federal Acquisition Regulations...—inclusion of Iraqi end products. As prescribed in 225.1101(7), use the following provision: Trade Agreements Certificate—Inclusion of Iraqi End Products (SEP 2008) (a) Definitions. Designated country end product,...

  10. 48 CFR 252.225-7022 - Trade agreements certificate-inclusion of Iraqi end products.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... certificate-inclusion of Iraqi end products. 252.225-7022 Section 252.225-7022 Federal Acquisition Regulations...—inclusion of Iraqi end products. As prescribed in 225.1101(7), use the following provision: Trade Agreements Certificate—Inclusion of Iraqi End Products (SEP 2008) (a) Definitions. Designated country end product,...

  11. Microbial methanol formation: A major end product of pectin metabolism

    SciTech Connect

    Schink, B.; Zeikus, J.G.

    1980-01-01

    Various pectinolytic strains of Clostridium, Erwinia, and Pseudomonas species produced methanol as a major end product during growth on pectin but not on glucose of polygalacturonic acid. Pectin metabolism of Clostridium butyricum strain 4PI correlated with a final product concentration of 16 mM at the end of growth, and a 1:1 stoichiometry for methanol production and percent initial substrate methoxylation. Growth on pectin was associated with high activity of pectin methylesterase and the absence of methanol consumption. The ecological significance of pectin metabolism and the establishment of microbial methylotrophic metabolism in nature is discussed.

  12. End-product inhibition and acidification limit biowaste fermentation efficiency.

    PubMed

    Probst, Maraike; Walter, Andreas; Dreschke, Gilbert; Fornasier, Flavio; Pümpel, Thomas; Walde, Janette; Insam, Heribert

    2015-12-01

    Converting waste to resource may mitigate environmental pollution and global resource limitation. The platform chemical lactic acid can be produced from biowaste and its liquid fraction after solid-liquid separation. A fermentation step for lactic acid production prior to the conversion of biowaste to methane and organic fertilizer would increase the biowaste's value. Despite the huge potential and promising results of the treatment procedure, the reasons for efficiency loss observed previously need to be addressed in order to pave the way for an up-scaling of the fermentation process. Therefore, biowaste was fermented applying pH control, acid extraction and glucose addition in order to counteract reasons such as acidification, end-product inhibition and carbon limitation, respectively. The fermentation was competitive compared to other renewable lactic acid production substrates and reached a maximum productivity of >5 g Clactic acidg(-1)Ch(-1) and a concentration exceeding 30 g L(-1). A combination of acidification and end-product inhibition was identified as major obstacle. Lactobacillus crispatus and its closest relatives were identified as key lactic acid producers within the process using Miseq Illumina sequencing. PMID:26433150

  13. Protein Glycosylation in Cancer

    PubMed Central

    Stowell, Sean R.; Ju, Tongzhong; Cummings, Richard D.

    2015-01-01

    Neoplastic transformation results in a wide variety of cellular alterations that impact the growth, survival, and general behavior of affected tissue. Although genetic alterations underpin the development of neoplastic disease, epigenetic changes can exert an equally significant effect on neoplastic transformation. Among neoplasia-associated epigenetic alterations, changes in cellular glycosylation have recently received attention as a key component of neoplastic progression. Alterations in glycosylation appear to not only directly impact cell growth and survival but also facilitate tumor-induced immunomodulation and eventual metastasis. Many of these changes may support neoplastic progression, and unique alterations in tumor-associated glycosylation may also serve as a distinct feature of cancer cells and therefore provide novel diagnostic and even therapeutic targets. PMID:25621663

  14. Glycosylation of Skeletal Calsequestrin

    PubMed Central

    Sanchez, Emiliano J.; Lewis, Kevin M.; Munske, Gerhard R.; Nissen, Mark S.; Kang, ChulHee

    2012-01-01

    Calsequestrin (CASQ) serves as a major Ca2+ storage/buffer protein in the sarcoplasmic reticulum (SR). When purified from skeletal muscle, CASQ1 is obtained in its glycosylated form. Here, we have confirmed the specific site and degree of glycosylation of native rabbit CASQ1 and have investigated its effect on critical properties of CASQ by comparison with the non-glycosylated recombinant form. Based on our comparative approach utilizing crystal structures, Ca2+ binding capacities, analytical ultracentrifugation, and light-scattering profiles of the native and recombinant rabbit CASQ1, we propose a novel and dynamic role for glycosylation in CASQ. CASQ undergoes a unique degree of mannose trimming as it is trafficked from the proximal endoplasmic reticulum to the SR. The major glycoform of CASQ (GlcNAc2Man9) found in the proximal endoplasmic reticulum can severely hinder formation of the back-to-back interface, potentially preventing premature Ca2+-dependent polymerization of CASQ and ensuring its continuous mobility to the SR. Only trimmed glycans can stabilize both front-to-front and the back-to-back interfaces of CASQ through extensive hydrogen bonding and electrostatic interactions. Therefore, the mature glycoform of CASQ (GlcNAc2Man1–4) within the SR can be retained upon establishing a functional high capacity Ca2+ binding polymer. In addition, based on the high resolution structures, we propose a molecular mechanism for the catecholaminergic polymorphic ventricular tachycardia (CPVT2) mutation, K206N. PMID:22170046

  15. A Study of Aberrant Glycosylation in Simulated Microgravity Using Laser Induced AutoFluorescence and Flow Cytometry

    NASA Technical Reports Server (NTRS)

    Lawless, B. DeSales

    1999-01-01

    A number of pathologies and cellular dysfunctions including neoplasms have been correlated with autofluorescence. The complications of aging and diabetes have been associated with the accumulation of non-enzymatic glycosylations of tissue macromolecules. These products are known as the Advanced Glycosylated End Products (AGEs). A physical property associated with AGEs is the emission of 570 mn or 630 nm light energy (autofluorescence) following the absorption of 448 mm energy associated with the argon laser. This investigation sought to assess the induction of argon-laser induced autofluorescence in a variety of in vitro culture systems. Different fluorescence intensities distinguished tumor lines from normal cell populations. Laser-stimulated autofluorescence discriminated primary cultures of lymphocytes grown in the presence of excess glucose as opposed to normal glucose concentrations. The effects of deglycosylating agents upon laser-induced autofluorescence were also assessed. The studies included studies of cell cycle analysis using Propidium Iodide stained DNA of cells grown in simulated microgravity using NASA Bioreactor Vessels in media of normal and elevated glucose concentrations.

  16. Glycosylation of conotoxins.

    PubMed

    Gerwig, Gerrit J; Hocking, Henry G; Stöcklin, Reto; Kamerling, Johannis P; Boelens, Rolf

    2013-03-01

    Conotoxins are small peptides present in the venom of cone snails. The snail uses this venom to paralyze and capture prey. The constituent conopeptides display a high level of chemical diversity and are of particular interest for scientists as tools employed in neurological studies and for drug development, because they target with exquisite specificity membrane receptors, transporters, and various ion channels in the nervous system. However, these peptides are known to contain a high frequency and variability of post-translational modifications-including sometimes O-glycosylation-which are of importance for biological activity. The potential application of specific conotoxins as neuropharmalogical agents and chemical probes requires a full characterization of the relevant peptides, including the structure of the carbohydrate part. In this review, the currently existing knowledge of O-glycosylation of conotoxins is described. PMID:23455513

  17. Determination of Glycosylation Sites and Site-specific Heterogeneity in Glycoproteins

    PubMed Central

    An, Hyun Joo; Froehlich, John W.; Lebrilla, Carlito B.

    2009-01-01

    Summary of Recent Advances Glycosylation is one of the most common post-translational modifications (PTMs) of proteins. At least 50% of human proteins are glycosylated with some estimates being as high as 70%. Glycoprotein analysis requires determining both the sites of glycosylation as well as the glycan structures associated with each site. Recent advances have led to the development of new analytical methods that employ mass spectrometry extensively making it possible to obtain the glycosylation site and the site microheterogeneity. These tools will be important for the eventual development of glycoproteomics. PMID:19700364

  18. Glycosylation of Conotoxins

    PubMed Central

    Gerwig, Gerrit J.; Hocking, Henry G.; Stöcklin, Reto; Kamerling, Johannis P.; Boelens, Rolf

    2013-01-01

    Conotoxins are small peptides present in the venom of cone snails. The snail uses this venom to paralyze and capture prey. The constituent conopeptides display a high level of chemical diversity and are of particular interest for scientists as tools employed in neurological studies and for drug development, because they target with exquisite specificity membrane receptors, transporters, and various ion channels in the nervous system. However, these peptides are known to contain a high frequency and variability of post-translational modifications—including sometimes O-glycosylation—which are of importance for biological activity. The potential application of specific conotoxins as neuropharmalogical agents and chemical probes requires a full characterization of the relevant peptides, including the structure of the carbohydrate part. In this review, the currently existing knowledge of O-glycosylation of conotoxins is described. PMID:23455513

  19. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Knowledge of Child Labor for Listed End Products. 52.222-18 Section 52.222-18 Federal Acquisition... CONTRACT CLAUSES Text of Provisions and Clauses 52.222-18 Certification Regarding Knowledge of Child Labor... Regarding Knowledge of Child Labor for Listed End Products (FEB 2001) (a) Definition. Forced or...

  20. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Regarding Knowledge of Child Labor for Listed End Products (FEB 2001) (a) Definition. Forced or indentured... Certification as to Forced or Indentured Child Labor, identified by their country of origin. There is a..., produced, or manufactured by forced or indentured child labor. Listed End Product Listed Countries...

  1. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Regarding Knowledge of Child Labor for Listed End Products (FEB 2001) (a) Definition. Forced or indentured... Certification as to Forced or Indentured Child Labor, identified by their country of origin. There is a..., produced, or manufactured by forced or indentured child labor. Listed End Product Listed Countries...

  2. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Regarding Knowledge of Child Labor for Listed End Products (FEB 2001) (a) Definition. Forced or indentured... Certification as to Forced or Indentured Child Labor, identified by their country of origin. There is a..., produced, or manufactured by forced or indentured child labor. Listed End Product Listed Countries...

  3. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Regarding Knowledge of Child Labor for Listed End Products (FEB 2001) (a) Definition. Forced or indentured... Certification as to Forced or Indentured Child Labor, identified by their country of origin. There is a..., produced, or manufactured by forced or indentured child labor. Listed End Product Listed Countries...

  4. 76 FR 61282 - Defense Federal Acquisition Regulation Supplement; Definition of “Qualifying Country End Product...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... INFORMATION: I. Background DoD published a proposed rule in the Federal Register at 76 FR 32845 on June 6... Regulation Supplement; Definition of ``Qualifying Country End Product'' (DFARS Case 2011-D028) AGENCY... definition of ``qualifying country end product.'' This final rule eliminates the component test...

  5. [Non-enzymatic glycosylation of dietary protein in vitro].

    PubMed

    Bednykh, B S; Evdokimov, I A; Sokolov, A I

    2015-01-01

    Non-enzymatic glycosylation of proteins, based on discovered by Mayarn reaction of carbohydrate aldehyde group with a free amino group of a protein molecule, is well known to experts in biochemistry of food industry. Generated brown solid in some cases give the product marketable qualities--crackling bread--in others conversely, worsen the product. The biological effects of far-advanced products of non-enzymatic protein glycosylation reaction have not been studied enough, although it was reported previously that they are not split by digestive enzymes and couldn't be absorbed by animals. The objective of this work was to compare the depth of glycosylation of different food proteins of animal and vegetable origin. The objects of the study were proteins of animal (casein, lactoglobulin, albumin) and vegetable (soy isolate, proteins of rice flour, buckwheat, oatmeal) origin, glucose and fructose were selected as glycosylation agents, exposure 15 days at 37 degrees C. Lactoglobulin was glycosylated to a lesser extent among the proteins of animal origin while protein of oatmeal was glycosylated in the least degree among vegetable proteins. Conversely, such proteins as casein and soya isolate protein bound rather large amounts of carbohydrates. Fructose binding with protein was generally higher than the binding of glucose. The only exception was a protein of oatmeal. When of glucose and fructose simultaneously presented in the incubation medium, glucose binding usually increased while binding of fructose, in contrast, reduced. According to the total amount of carbohydrate (mcg), which is able to attach a protein (mg) the studied food proteins located in the following order: albumin (38) > soy protein isolate (23) > casein (15,) > whey protein rice flour protein (6) > protein from buckwheat flour (3) > globulin (2) > protein of oatmeal (0.3). The results obtained are to be used to select the optimal combination of proteins and carbohydrates, in which the glycosylation

  6. Nontargeted Modification-Specific Metabolomics Investigation of Glycosylated Secondary Metabolites in Tea (Camellia sinensis L.) Based on Liquid Chromatography-High-Resolution Mass Spectrometry.

    PubMed

    Dai, Weidong; Tan, Junfeng; Lu, Meiling; Xie, Dongchao; Li, Pengliang; Lv, Haipeng; Zhu, Yin; Guo, Li; Zhang, Yue; Peng, Qunhua; Lin, Zhi

    2016-09-01

    Glycosylation on small molecular metabolites modulates a series of biological events in plants. However, a large number of glycosides have not been discovered and investigated using -omics approaches. Here, a general strategy named "nontargeted modification-specific metabolomics" was applied to map the glycosylation of metabolites. The key aspect of this method is to adopt in-source collision-induced dissociation to dissociate the glycosylated metabolite, causing a characteristic neutral loss pattern, which acts as an indicator for the glycosylation identification. In an exemplary application in green teas, 120 glucosylated/galactosylated, 38 rhamnosylated, 21 rutinosylated, and 23 primeverosylated metabolites were detected simultaneously. Among them, 61 glycosylated metabolites were putatively identified according to current tea metabolite databases. Thanks to the annotations of glycosyl moieties in advance, the method aids metabolite identifications. An additional 40 novel glycosylated metabolites were tentatively elucidated. This work provides a feasible strategy to discover and identify novel glycosylated metabolites in plants. PMID:27541009

  7. Advanced Glycation End Products Induce Obesity and Hepatosteatosis in CD-1 Wild-Type Mice

    PubMed Central

    Sayej, Wael N.; Knight III, Paul R.; Guo, Weidun Alan; Mullan, Barbara; Ohtake, Patricia J.; Davidson, Bruce A.; Khan, Abdur; Baker, Robert D.; Baker, Susan S.

    2016-01-01

    AGEs are a heterogeneous group of molecules formed from the nonenzymatic reaction of reducing sugars with free amino groups of proteins, lipids, and/or nucleic acids. AGEs have been shown to play a role in various conditions including cardiovascular disease and diabetes. In this study, we hypothesized that AGEs play a role in the “multiple hit hypothesis” of nonalcoholic fatty liver disease (NAFLD) and contribute to the pathogenesis of hepatosteatosis. We measured the effects of various mouse chows containing high or low AGE in the presence of high or low fat content on mouse weight and epididymal fat pads. We also measured the effects of these chows on the inflammatory response by measuring cytokine levels and myeloperoxidase activity levels on liver supernatants. We observed significant differences in weight gain and epididymal fat pad weights in the high AGE-high fat (HAGE-HF) versus the other groups. Leptin, TNF-α, IL-6, and myeloperoxidase (MPO) levels were significantly higher in the HAGE-HF group. We conclude that a diet containing high AGEs in the presence of high fat induces weight gain and hepatosteatosis in CD-1 mice. This may represent a model to study the role of AGEs in the pathogenesis of hepatosteatosis and steatohepatitis. PMID:26942201

  8. The Possible Mechanism of Advanced Glycation End Products (AGEs) for Alzheimer’s Disease

    PubMed Central

    Ko, Shun-Yao; Ko, Hshin-An; Chu, Kuo-Hsiung; Shieh, Tzong-Ming; Chi, Tzong-Cherng; Chen, Hong-I; Chang, Weng-Cheng; Chang, Shu-Shing

    2015-01-01

    Amyloid precursor protein (APP) has been modified by β and γ-secretase that cause amyloid deposits (plaques) in neuronal cells. Glyceraldhyde-derived AGEs has been identified as a major source of neurotoxicity in Alzheimer’s disease (AD). In a previous study, we demonstrated that glyceraldehyde-derived AGEs increase APP and Aβ via ROS. Furthermore, the combination of AGEs and Aβ has been shown to enhance neurotoxicity. In mice, APP expression is increased by tail vein injection of AGEs. This evidence suggests a correlation between AGEs and the development of AD. However, the role played by AGEs in the pathogenesis of AD remains unclear. In this report, we demonstrate that AGEs up-regulate APP processing protein (BACE and PS1) and Sirt1 expression via ROS, but do not affect the expression of downstream antioxidant genes HO-1 and NQO-1. Moreover, we found that AGEs increase GRP78 expression and enhance the cell death-related pathway p53, bcl-2/bax ratio, caspase 3. These results indicate that AGEs impair the neuroprotective effects of Sirt1 and lead to neuronal cell death via ER stress. Our findings suggest that AGEs increase ROS production, which stimulates downstream pathways related to APP processing, Aβ production, Sirt1, and GRP78, resulting in the up-regulation of cell death related pathway. This in-turn enhances neuronal cell death, which leads to the development of AD. PMID:26587989

  9. Advanced Glycation End Products Modulate Structure and Drug Binding Properties of Albumin.

    PubMed

    Awasthi, Saurabh; Murugan, N Arul; Saraswathi, N T

    2015-09-01

    The extraordinary ligand binding properties of albumin makes it a key player in the pharmacokinetics and pharmacodynamics of many vital drugs. Albumin is highly susceptible for nonenzymatic glycation mediated structural modifications, and there is a need to determine structural and functional impact of specific AGEs modifications. The present study was aimed toward determining the AGE mediated structure and function changes, primarily looking into the effect on binding affinity of drugs in the two major drug binding sites of albumin. The impact of the two most predominant AGEs modifications, i.e., carboxyethyllysine (CEL) and argpyrimidine (Arg-P), was studied on the basis of the combination of in vitro and in silico experiments. In vitro studies were carried out by AGEs modification of bovine serum albumin (BSA) for the formation of Arg-P and CEL followed by drug interaction studies. In silico studies involved molecular dynamics (MD) simulations and docking studies for native and AGEs modified BSAs. In particular the side chain modification was specifically carried out for the residues in the drug binding sites, i.e., Arg-194, Arg-196, Arg-198, and Arg-217, and Lys-204 (site I) and Arg-409 and Lys-413 (site II). The equilibrated structures of native BSA (n-BSA) and glycated BSA (G-BSA) as obtained from MD were used for drug binding studies using molecular docking approach. It was evident from the results of both in vitro and in silico drug interaction studies that AGEs modification results in the reduced drug binding affinity for tolbutamide (TLB) and ibuprofen (IBP) in sites I and II. Moreover, the AGEs modification mediated conformational changes resulted in the shallow binding pockets with reduced accessibility for drugs. PMID:26281017

  10. Relationship of advanced glycation end products and their receptor to pelvic organ prolapse

    PubMed Central

    Chen, Yisong; Huang, Jian; Hu, Changdong; Hua, Keqin

    2015-01-01

    Objective: The aims of this study are to detect levels of AGEs and RAGE and SNPs for RAGE in vaginal tissues of women with POP and rats in a repair location, and to explore the relationship between AGEs-RAGE pathway and POP. Methods: This study involved human vaginal tissues in fornix from 44 women with POP and 46 women without POP who were assigned to pelvic floor reconstruction or LAVH. The proteins of AGEs, collagen I, and RAGE were detected by immunohistochemistry and Western blot with appropriate primary antibodies. The entire RAGE gene of 24 women with POP and 25 controls were sequenced, and SNPs within were detected. Then, sixty 8-week-old female Sprague-Dawley rats subjected to abdominal defect were divided into three surgical pelvic floor reconstruction repair groups (n = 20/group): A, repair with non-absorable prolene mesh; B, repair with absorbable SIS mesh; and C, a no repair control group. 3, 9, 15, and 21 months after operation, rats were sacrificed and the expression of AGEs, RAGE and collagen I in the tissues of repair location were detected in the various experimental groups. Statistical analysis included comparison of means (Student’s t-test) and proportions (Chi-square test or Fisher test). Results: By both immunohistochemistry and Western blot, patients with POP showed higher protein expression of AGEs of POP than controls (P < 0.05). In contrast, the expression of collagen I was lower in POP patients than in the control group (P < 0.05). No differences in the expression of RAGE between the POP patients and controls were observed (P > 0.05). In POP patients, the expression of collagen I decreased particularly in patients ≥ 60 years old (P < 0.05), but there were no different in the expression of AGEs and RAGE dependent on age (P > 0.05). RAGE gene sequence variance analysis identified 18 variable loci, but only two of these were potential SNPs: rs184003 (1806), rs55640627 (2346) (P < 0.05). Both rs184003 and rs55640627 are both intronic variants, indicating that they may not influence the structure of RAGE. In rat surgical repair model, group B showed a greater extent of abdominal prolapse than groups A and C (P < 0.05). Consistent with this, the expression of AGEs in group B was higher than groups A and C (P < 0.05), and collagen I in group B was lower than the two others, further supporting our notion that AGEs are inversely related to type I collagen content. Conclusions: In summary, this study demonstrates that AGEs and RAGE might play important roles in the physiopathology of POP. Further studies are required to explore mechanisms of how AGEs-RAGE pathway may contribute to tissue degeneration and fragility in POP. PMID:26045736

  11. Congenital Disorders of Glycosylation and Intellectual Disability

    ERIC Educational Resources Information Center

    Wolfe, Lynne A.; Krasnewich, Donna

    2013-01-01

    The congenital disorders of glycosylation (CDG) are a rapidly growing group of inborn errors of metabolism that result from defects in the synthesis of glycans. Glycosylation is a major post-translational protein modification and an estimated 2% of the human genome encodes proteins for glycosylation. The molecular bases for the current 60…

  12. The medical effects of radioactive fall-out: role of stable end-products?

    PubMed Central

    Burrows, B. A.; Cardarelli, J. C.; Boling, E. A.; Sinex, F. M.

    1981-01-01

    To summarize, from preliminary observations on the possible effects of radioactive fall-out, it may be inferred that in addition to the secondary products of ionizing irradiation per se, the stable end-products of the transmutation of certain radionuclides may adversely influence cellular metabolism, including mutagenesis. The discussion of the possible role of intracellular barium as an end-product of 137Cs decay is offered as an example of an unpredictable number of broad ecological, as well as the more limited medical, effects that may be of both clinical and climatological significance. Images Fig. 1 Fig. 2 PMID:7281411

  13. Golgi glycosylation and human inherited diseases.

    PubMed

    Freeze, Hudson H; Ng, Bobby G

    2011-09-01

    The Golgi factory receives custom glycosylates and dispatches its cargo to the correct cellular locations. The process requires importing donor substrates, moving the cargo, and recycling machinery. Correctly glycosylated cargo reflects the Golgi's quality and efficiency. Genetic disorders in the specific equipment (enzymes), donors (nucleotide sugar transporters), or equipment recycling/reorganization components (COG, SEC, golgins) can all affect glycosylation. Dozens of human glycosylation disorders fit these categories. Many other genes, with or without familiar names, well-annotated pedigrees, or likely homologies will join the ranks of glycosylation disorders. Their broad and unpredictable case-by-case phenotypes cross the traditional medical specialty boundaries. The gene functions in patients may be elusive, but their common feature may include altered glycosylation that provide clues to Golgi function. This article focuses on a group of human disorders that affect protein or lipid glycosylation. Readers may find it useful to generalize some of these patient-based, translational observations to their own research. PMID:21709180

  14. Golgi Glycosylation and Human Inherited Diseases

    PubMed Central

    Freeze, Hudson H.; Ng, Bobby G.

    2011-01-01

    The Golgi factory receives custom glycosylates and dispatches its cargo to the correct cellular locations. The process requires importing donor substrates, moving the cargo, and recycling machinery. Correctly glycosylated cargo reflects the Golgi's quality and efficiency. Genetic disorders in the specific equipment (enzymes), donors (nucleotide sugar transporters), or equipment recycling/reorganization components (COG, SEC, golgins) can all affect glycosylation. Dozens of human glycosylation disorders fit these categories. Many other genes, with or without familiar names, well-annotated pedigrees, or likely homologies will join the ranks of glycosylation disorders. Their broad and unpredictable case-by-case phenotypes cross the traditional medical specialty boundaries. The gene functions in patients may be elusive, but their common feature may include altered glycosylation that provide clues to Golgi function. This article focuses on a group of human disorders that affect protein or lipid glycosylation. Readers may find it useful to generalize some of these patient-based, translational observations to their own research. PMID:21709180

  15. Marked increase in rat red blood cell membrane protein glycosylation by one-month treatment with a cafeteria diet

    PubMed Central

    Oliva, Laia; Baron, Cristian; Fernández-López, José-Antonio; Remesar, Xavier

    2015-01-01

    Background and Objectives. Glucose, an aldose, spontaneously reacts with protein amino acids yielding glycosylated proteins. The compounds may reorganize to produce advanced glycosylation products, which regulatory importance is increasingly being recognized. Protein glycosylation is produced without the direct intervention of enzymes and results in the loss of function. Glycosylated plasma albumin, and glycosylated haemoglobin are currently used as index of mean plasma glucose levels, since higher glucose availability results in higher glycosylation rates. In this study we intended to detect the early changes in blood protein glycosylation elicited by an obesogenic diet. Experimental Design. Since albumin is in constant direct contact with plasma glucose, as are the red blood cell (RBC) membranes, we analyzed their degree or glycosylation in female and male rats, either fed a standard diet or subjected to a hyper-energetic self-selected cafeteria diet for 30 days. This model produces a small increase in basal glycaemia and a significant increase in body fat, leaving the animals in the initial stages of development of metabolic syndrome. We also measured the degree of glycosylation of hemoglobin, and the concentration of glucose in contact with this protein, that within the RBC. Glycosylation was measured by colorimetric estimation of the hydroxymethylfurfural liberated from glycosyl residues by incubation with oxalate. Results. Plasma glucose was higher in cafeteria diet and in male rats, both independent effects. However, there were no significant differences induced by sex or diet in either hemoglobin or plasma proteins. Purified RBC membranes showed a marked effect of diet: higher glycosylation in cafeteria rats, which was more marked in females (not in controls). In any case, the number of glycosyl residues per molecule were higher in hemoglobin than in plasma proteins (after correction for molecular weight). The detected levels of glucose in RBC were lower

  16. Therapeutic potential of targeting lipid aldehydes and lipoxidation end-products in the treatment of ocular disease.

    PubMed

    McDowell, Rosemary E; McGeown, J Graham; Stitt, Alan W; Curtis, Tim M

    2013-02-01

    Lipoxidation reactions and the subsequent accumulation of advanced lipoxidation end products (ALEs) have been implicated in the pathogenesis of many of the leading causes of visual impairment. Here, we begin by outlining some of the major lipid aldehydes produced through lipoxidation reactions, the ALEs formed upon their reaction with proteins, and the endogenous aldehyde metabolizing enzymes involved in protecting cells against lipoxidation mediated damage. Discussions are subsequently focused on the clinical and experimental evidence supporting the contribution of lipid aldehydes and ALEs in the development of ocular diseases. From these discussions, it is clear that inhibition of lipoxidation reactions and ALE formation could represent a new therapeutic avenue for the treatment of a broad range of ocular disorders. Current and emerging pharmacological strategies to prevent or neutralize the effects of lipid aldehydes and ALEs are therefore considered, with particular emphasis on the potential of these drugs for treatment of diseases of the eye. PMID:23360143

  17. Altered expression of natively glycosylated dystroglycan in pediatric solid tumors

    PubMed Central

    Martin, Laura T.; Glass, Matthew; Dosunmu, Eniolami; Martin, Paul T.

    2010-01-01

    Summary Altered glycosylation and/or expression of dystroglycan have been reported in forms of congenital muscular dystrophy as well as in cancers of the breast, colon, and oral epithelium. To date, however, there has been no study of the expression of dystroglycan in pediatric solid tumors. Using a combination of immunostaining on tissue microarrays and immunoblotting of snap-frozen unfixed tissues, we demonstrate a significant reduction in native α dystroglycan expression in pediatric alveolar rhabdomyosarcoma (RMS), embryonal RMS, neuroblastoma (NBL), and medulloblastoma, whereas expression of β dystroglycan, which is cotranslated with α dystroglycan, is largely unchanged. Loss of native α dystroglycan expression was significantly more pronounced in stage 4 NBL than in pooled samples of stage 1 and stage 2 NBL, suggesting that loss of native α dystroglycan expression increases with advancing tumor stage. Neuroblastoma and RMS samples with reduced expression of native α dystroglycan also showed reduced laminin binding in laminin overlay experiments. Expression of natively glycosylated α dystroglycan was not altered in several other pediatric tumor types when compared with appropriate normal tissue controls. These data provide the first evidence that α dystroglycan glycosylation and laminin binding to α dystroglycan are altered in certain pediatric solid tumors and suggest that aberrant dystroglycan glycosylation may contribute to tumor cell biology in patients with RMS, medulloblastoma, and NBL. PMID:17640712

  18. Proteolytic Cleavage Driven by Glycosylation.

    PubMed

    Kötzler, Miriam P; Withers, Stephen G

    2016-01-01

    Proteolytic processing of human host cell factor 1 (HCF-1) to its mature form was recently shown, unexpectedly, to occur in a UDP-GlcNAc-dependent fashion within the transferase active site of O-GlcNAc-transferase (OGT) (Lazarus, M. B., Jiang, J., Kapuria, V., Bhuiyan, T., Janetzko, J., Zandberg, W. F., Vocadlo, D. J., Herr, W., and Walker, S. (2013) Science 342, 1235-1239). An interesting mechanism involving formation and then intramolecular rearrangement of a covalent glycosyl ester adduct of the HCF-1 polypeptide was proposed to account for this unprecedented proteolytic activity. However, the key intermediate remained hypothetical. Here, using a model enzyme system for which the formation of a glycosyl ester within the enzyme active site has been shown unequivocally, we show that ester formation can indeed lead to proteolysis of the adjacent peptide bond, thereby providing substantive support for the mechanism of HCF-1 processing proposed. PMID:26515062

  19. Radioactivity and associated radiation hazards in ceramic raw materials and end products.

    PubMed

    Viruthagiri, G; Rajamannan, B; Suresh Jawahar, K

    2013-12-01

    Studies have been planned to obtain activity and associated radiation hazards in ceramic raw materials (quartz, feldspar, clay, zircon, kaolin, grog, alumina bauxite, baddeleyite, masse, dolomite and red mud) and end products (ceramic brick, glazed ceramic wall and floor tiles) as the activity concentrations of uranium, thorium and potassium vary from material to material. The primordial radionuclides in ceramic raw materials and end products are one of the sources of radiation hazard in dwellings made of these materials. By the determination of the activity level in these materials, the indoor radiological hazard to human health can be assessed. This is an important precautionary measure whenever the dose rate is found to be above the recommended limits. The aim of this work was to measure the activity concentration of (226)Ra, (232)Th and (40)K in ceramic raw materials and end products. The activity of these materials has been measured using a gamma-ray spectrometry, which contains an NaI(Tl) detector connected to multichannel analyser (MCA). Radium equivalent activity, alpha-gamma indices and radiation hazard indices associated with the natural radionuclides are calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant international legislation and guidance and compared with the results of similar studies reported in different countries. The results suggest that the use of ceramic end product samples examined in the construction of dwellings, workplace and industrial buildings is unlikely to give rise to any significant radiation exposure to the occupants. PMID:23765074

  20. Neurology of inherited glycosylation disorders

    PubMed Central

    Freeze, HH; Eklund, E A; Ng, BG; Patterson, M C

    2013-01-01

    Congenital disorders of glycosylation comprise most of the nearly 70 genetic disorders known to be caused by impaired synthesis of glycoconjugates. The effects are expressed in most organ systems, and most involve the nervous system. Typical manifestations include structural abnormalities, (eg, rapidly progressive cerebellar atrophy), myopathies (including congenital muscular dystrophies and limb-girdle dystrophies), strokes and stroke-like episodes, epileptic seizures, developmental delay, and demyelinating neuropathy. Patients can have neurological symptoms associated with coagulopathies, immune dysfunction with or without infections, and cardiac, renal, or hepatic failure, which are common features of glycosylation disorders. The diagnosis of congenital disorders of glycosylation should be considered for any patient with multisystem disease and in those with more specific phenotypic features. Measurement of concentrations of selected glycoconjugates can be used to screen for many of these disorders, and molecular diagnosis is becoming more widely available in clinical practice. Disease-modifying treatments are available for only a few disorders, but all affected individuals benefit from early diagnosis and aggressive management. PMID:22516080

  1. NEUROLOGICAL ASPECTS OF HUMAN GLYCOSYLATION DISORDERS

    PubMed Central

    Freeze, Hudson H.; Eklund, Erik A.; Ng, Bobby G.; Patterson, Marc C.

    2016-01-01

    This review will present principles of glycosylation, describe the relevant glycosylation pathways and their related disorders, and highlight some of the neurological aspects and issues that continue to challenge researchers. Over 100 rare human genetic disorders that result from deficiencies in the different glycosylation pathways are known today. Most of these disorders impact the central and/or peripheral nervous systems. Patients typically have developmental delay/intellectual disability, hypotonia, seizures, neuropathy, and metabolic abnormalities in multiple organ systems. Between these disorders there is great clinical diversity because all cell types differentially glycosylate proteins and lipids. The patients have hundreds of mis-glycosylated products afflicting a myriad of processes including cell signaling, cell-cell interaction and cell migration. This vast complexity in glycan composition and function, along with limited analytic tools has impeded the identification of key glycosylated molecules that cause pathologies, and to date few critical target proteins have been pinpointed. PMID:25840006

  2. ECM Proteins Glycosylation and Relation to Diabetes

    NASA Astrophysics Data System (ADS)

    Pernodet, Nadine; Bloomberg, Ayla; Sood, Vandana; Slutsky, Lenny; Ge, Shouren; Clark, Richard; Rafailovich, Miriam

    2004-03-01

    The chemical modification and crosslinking of proteins by sugar glycosylation contribute to the aging of tissue proteins, and acceleration of this reaction during hyperglycemia is implicated in the pathogenesis of diabetic complications, such as disorder of the wound healing. Advanced glycation endproducts (AGEs) formation and protein crosslinking are irreversible processes that alter the structural and functional properties of proteins, lipid components and nucleic acids. And the mechanism, by which it happens, is not clear. Fibrinogen and fibronectin are plasma proteins, which play a major role in human wound healing. Fibrinogen converts to an insoluble fibrin "gel" following a cut, which eventually forms a clot to prevent blood loss, to direct cell adhesion and migration for forming scars. Fibronectin is a critical protein for cell adhesion and migration in wound healing. The effects of glucose on the binding of these plasma proteins from the extra cellular matrix (ECM) were followed at different concentrations by atomic force microscopy and lateral force modulation to measure the mechanical response of the samples. Glucose solutions (1, 2, and 3mg/mL) were incubated with the protein (100 mg/ml) and silicon (Si) substrates spun with sulfonated polystyrene (SPS) 28% for five days. Data showed that not only the organization of the protein on the surface was affected but also its mechanical properties. At 3 mg/mL glucose, Fn fibers were observed to be harder than those of the control, in good agreement with our hypothesis that glycosylation hardens tissues by crosslinking of proteins in the ECM and might cause fibers to break more easily.

  3. Characterization of Clostridium thermocellum strains with disrupted fermentation end-product pathways

    SciTech Connect

    Van Der Veen, Douwe; Lo, Jonathan; Brown, Steven D; Johnson, Courtney M; Tschaplinski, Timothy J; Martin, Madhavi Z; Engle, Nancy L; Van den Berg, Robert A; Argyros, Aaron; Caiazza, Nicky; Guss, Adam M; Lynd, Lee R

    2013-01-01

    Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of L-lactate (Dldh) and/or acetate (Dpta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end-products. Cellobiose-grown cultures of the Dldh strain had identical biomass accumulation, fermentation end-products, transcription profile, and intracellular metabolite concentrations compared to its parent strain (DSM1313 Dhpt Dspo0A). The Dpta-deficient strain grew slower and had 30 % lower final biomass concentration compared to the parent strain, yet produced 75% more ethanol. A Dldh Dpta double-mutant strain evolved for faster growth had a growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to Dpta. Free amino acids were secreted by all examined strains, with both Dpta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for Dldh Dpta reached 5 mM by the end of growth, or 2.7 % of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to sixfold in the Dpta and 16-fold in the Dldh Dpta strain. We hypothesize that the deletions in fermentation end-product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP* through increased production of amino acids.

  4. Characterization of Clostridium thermocellum strains with disrupted fermentation end product pathways

    SciTech Connect

    Van Der Veen, Douwe; Lo, Jonathan; Brown, Steven D; Johnson, Courtney M; Tschaplinski, Timothy J; Martin, Madhavi Z; Engle, Nancy L; Argyros, Aaron; Van den Berg, Robert A; Caiazza, Nicky; Guss, Adam M; Lynd, Lee R

    2013-01-01

    Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of Llactate ( ldh) and/or acetate ( pta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end products. Cellobiose-grown cultures of the ldh strain had identical biomass accumulation, fermentation end products, transcription profile and intracellular metabolite concentrations compared to its parent strain (DSM1313 hpt spo0A). The pta-deficient strain grew slower and had 30% lower final biomass concentration compared to the parent strain, yet produced 75% more ethanol. A ldh pta double mutant strain evolved for faster growth had growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to pta. Free amino acids were secreted by all examined strains, with both pta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for ldh pta reached 5 mM by the end of growth, or 2.7% of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to 6-fold in the pta and 16-fold in the ldh pta strain. We hypothesize that the deletions in fermentation end product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP+ through increased production of amino acids.

  5. Radiometric analysis of raw materials and end products in the Turkish ceramics industry

    NASA Astrophysics Data System (ADS)

    Turhan, Ş.; Arıkan, İ. H.; Demirel, H.; Güngör, N.

    2011-05-01

    This study presents the findings of radiometric analysis carried out to determine the activity concentrations of natural radionuclides in raw materials (clay, kaolin, quartz, feldspar, dolomite, alumina, bauxite, zirconium minerals, red mud and frit) and end products (glazed ceramic wall and floor tiles) in the Turkish ceramics industry. Hundred forty-six samples were obtained from various manufacturers and suppliers throughout the country and analyzed using gamma-ray spectrometer with HPGe detectors. Radiological parameters such as radium equivalent activity, activity concentration index and alpha index were calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant national and international legislation and guidance and compared with the results of similar studies reported in different countries. The results suggest that the use of ceramic end product samples examined in the construction of dwellings, workplaces and industrial buildings in Turkey is unlikely to give rise to any significant radiation exposure to the occupants.

  6. Systems Glycobiology: Integrating Glycogenomics, Glycoproteomics, Glycomics, and Other 'Omics Data Sets to Characterize Cellular Glycosylation Processes.

    PubMed

    Bennun, Sandra V; Hizal, Deniz Baycin; Heffner, Kelley; Can, Ozge; Zhang, Hui; Betenbaugh, Michael J

    2016-08-14

    The number of proteins encoded in the human genome has been estimated at between 20,000 and 25,000, despite estimates that the entire proteome contains more than a million proteins. One reason for this difference is due to many post-translational modifications of protein that contribute to proteome complexity. Among these, glycosylation is of particular relevance because it serves to modify a large number of cellular proteins. Glycogenomics, glycoproteomics, glycomics, and glycoinformatics are helping to accelerate our understanding of the cellular events involved in generating the glycoproteome, the variety of glycan structures possible, and the importance of roles that glycans play in therapeutics and disease. Indeed, interest in glycosylation has expanded rapidly over the past decade, as large amounts of experimental 'omics data relevant to glycosylation processing have accumulated. Furthermore, new and more sophisticated glycoinformatics tools and databases are now available for glycan and glycosylation pathway analysis. Here, we summarize some of the recent advances in both experimental profiling and analytical methods involving N- and O-linked glycosylation processing for biotechnological and medically relevant cells together with the unique opportunities and challenges associated with interrogating and assimilating multiple, disparate high-throughput glycosylation data sets. This emerging era of advanced glycomics will lead to the discovery of key glycan biomarkers linked to diseases and help establish a better understanding of physiology and improved control of glycosylation processing in diverse cells and tissues important to disease and production of recombinant therapeutics. Furthermore, methodologies that facilitate the integration of glycomics measurements together with other 'omics data sets will lead to a deeper understanding and greater insights into the nature of glycosylation as a complex cellular process. PMID:27423401

  7. Synthesis of oligosaccharides using per-O-trimethylsilyl-glycosyl iodides as glycosyl donor.

    PubMed

    Wang, Hong; Cui, Yanli; Zou, Rong; Cheng, Zhaodong; Yao, Weirong; Mao, Yangyi; Zhang, Yongmin

    2016-06-01

    Trimethylsilyl (TMS) protecting group has been found to be very useful for the simultaneous protection of both the glycosyl donor- and the acceptor-substrates in oligosaccharide synthesis. Thus, while the per-O-trimethylsilylated glycosyl iodides served as the glycosyl donor, those bearing selectively exposed primary hydroxyl groups were found suitable as the glycosyl acceptor for the reaction. The cheap and commercially available trialkylamine, triethylamine was found to be an effective promoter for the glycosylation. Importantly, the reaction was α-stereospecific and gave the products in 58%-78% yields. PMID:27077820

  8. 48 CFR 622.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Products Produced by Forced or Indentured Child Labor 622.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child Labor. (e)...

  9. 48 CFR 22.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Acquisition of Products Produced by Forced or Indentured Child Labor 22.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child...

  10. 48 CFR 622.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Products Produced by Forced or Indentured Child Labor 622.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child Labor. (e)...

  11. 48 CFR 622.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Products Produced by Forced or Indentured Child Labor 622.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child Labor. (e)...

  12. 48 CFR 22.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Acquisition of Products Produced by Forced or Indentured Child Labor 22.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child...

  13. 48 CFR 622.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Products Produced by Forced or Indentured Child Labor 622.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child Labor. (e)...

  14. 48 CFR 22.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Acquisition of Products Produced by Forced or Indentured Child Labor 22.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child...

  15. 48 CFR 622.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Products Produced by Forced or Indentured Child Labor 622.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child Labor. (e)...

  16. 48 CFR 22.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... end products on the List of Products Requiring Contractor Certification as to Forced or Indentured... Acquisition of Products Produced by Forced or Indentured Child Labor 22.1503 Procedures for acquiring end products on the List of Products Requiring Contractor Certification as to Forced or Indentured Child...

  17. Aberrant Glycosylation in the Human Trabecular Meshwork

    PubMed Central

    Sienkiewicz, Adam E.; Rosenberg, Brandon N.; Edwards, Genea; Carreon, Teresia A.; Bhattacharya, Sanjoy K.

    2014-01-01

    Purpose To determine the difference in protein glycosylation and glycosylation enzyme levels between glaucomatous and control trabecular meshwork (TM). Experimental design Glaucomatous and normal donor (n=12 each) TM tissues, Lectin-fluorescence, fluorophore assisted carbohydrate analyses, and quantitative mass spectrometry were used to determine the glycosylation levels. Primary TM cells and glycosylation inhibitors were used to determine their effect on cell shape and motility. Results In contrast to elevated levels of glycoproteins determined by lectin-fluorescence, simultaneous hyper and hypo-glycosylation in glaucomatous trabecular meshwork was revealed by fluorophore assisted carbohydrate analyses. Analyses of enzymes showed elevation of Beta-glycosidase 1 and decrease in Galactosyltransferase family 6 domain containing protein 1 in the glaucomatous trabecular meshwork. Quantitative mass spectrometry identified select protein level changes between glaucomatous and normal trabecular meshwork. Primary trabecular meshwork cells were treated with inhibitors to elicit hypo-glycosylation, which affected cell shape, motility, and fluorescent tracer transport across a layer of trabecular meshwork cells. Conclusions and clinical relevance Global protein glycosylation is aberrant in glaucomatous trabecular meshwork compared to controls. The results presented here suggest that the alteration in global TM protein glycosylation encompassing cellular and extracellular matrix proteins contributes to glaucoma pathology likely mediated through changes in properties of TM cells. PMID:24458570

  18. Glycosylation enables aesculin to activate Nrf2.

    PubMed

    Kim, Kyun Ha; Park, Hyunsu; Park, Hee Jin; Choi, Kyoung-Hwa; Sadikot, Ruxana T; Cha, Jaeho; Joo, Myungsoo

    2016-01-01

    Since aesculin, 6,7-dihydroxycoumarin-6-O-β-glucopyranoside, suppresses inflammation, we asked whether its anti-inflammatory activity is associated with the activation of nuclear factor-E2-related factor 2 (Nrf2), a key anti-inflammatory factor. Our results, however, show that aesculin marginally activated Nrf2. Since glycosylation can enhance the function of a compound, we then asked whether adding a glucose makes aesculin activate Nrf2. Our results show that the glycosylated aesculin, 3-O-β-d-glycosyl aesculin, robustly activated Nrf2, inducing the expression of Nrf2-dependent genes, such as heme oxygenase-1, glutamate-cysteine ligase catalytic subunit, and NAD(P)H quinone oxidoreductase 1 in macrophages. Mechanistically, 3-O-β-d-glycosyl aesculin suppressed ubiquitination of Nrf2, retarding degradation of Nrf2. Unlike aesculin, 3-O-β-d-glycosyl aesculin significantly suppressed neutrophilic lung inflammation, a hallmark of acute lung injury (ALI), in mice, which was not recapitulated in Nrf2 knockout mice, suggesting that the anti-inflammatory function of the compound largely acts through Nrf2. In a mouse model of sepsis, a major cause of ALI, 3-O-β-d-glycosyl aesculin significantly enhanced the survival of mice, compared with aesculin. Together, these results show that glycosylation could confer the ability to activate Nrf2 on aesculin, enhancing the anti-inflammatory function of aesculin. These results suggest that glycosylation can be a way to improve or alter the function of aesculin. PMID:27417293

  19. Glycosylation enables aesculin to activate Nrf2

    PubMed Central

    Kim, Kyun Ha; Park, Hyunsu; Park, Hee Jin; Choi, Kyoung-Hwa; Sadikot, Ruxana T.; Cha, Jaeho; Joo, Myungsoo

    2016-01-01

    Since aesculin, 6,7-dihydroxycoumarin-6-O-β-glucopyranoside, suppresses inflammation, we asked whether its anti-inflammatory activity is associated with the activation of nuclear factor-E2-related factor 2 (Nrf2), a key anti-inflammatory factor. Our results, however, show that aesculin marginally activated Nrf2. Since glycosylation can enhance the function of a compound, we then asked whether adding a glucose makes aesculin activate Nrf2. Our results show that the glycosylated aesculin, 3-O-β-d-glycosyl aesculin, robustly activated Nrf2, inducing the expression of Nrf2-dependent genes, such as heme oxygenase-1, glutamate-cysteine ligase catalytic subunit, and NAD(P)H quinone oxidoreductase 1 in macrophages. Mechanistically, 3-O-β-d-glycosyl aesculin suppressed ubiquitination of Nrf2, retarding degradation of Nrf2. Unlike aesculin, 3-O-β-d-glycosyl aesculin significantly suppressed neutrophilic lung inflammation, a hallmark of acute lung injury (ALI), in mice, which was not recapitulated in Nrf2 knockout mice, suggesting that the anti-inflammatory function of the compound largely acts through Nrf2. In a mouse model of sepsis, a major cause of ALI, 3-O-β-d-glycosyl aesculin significantly enhanced the survival of mice, compared with aesculin. Together, these results show that glycosylation could confer the ability to activate Nrf2 on aesculin, enhancing the anti-inflammatory function of aesculin. These results suggest that glycosylation can be a way to improve or alter the function of aesculin. PMID:27417293

  20. Chemoenzymatic Fc Glycosylation via Engineered Aldehyde Tags

    PubMed Central

    2014-01-01

    Glycoproteins with chemically defined glycosylation sites and structures are important biopharmaceutical targets and critical tools for glycobiology. One approach toward constructing such molecules involves chemical glycosylation of aldehyde-tagged proteins. Here, we report the installation of a genetically encoded aldehyde tag at the internal glycosylation site of the crystallizable fragment (Fc) of IgG1. We replaced the natural Fc N-glycosylation sequon with a five amino-acid sequence that was efficiently converted by recombinant formylglycine generating enzyme in vitro, thereby introducing aldehyde groups for subsequent chemical elaboration. Oxime-linked glycoconjugates were synthesized by conjugating aminooxy N-acetylglucosamine to the modified Fc followed by enzymatic transfer of complex N-glycans from corresponding glycan oxazolines by an EndoS-derived glycosynthase. In this manner we generated specific Fc glycoforms without relying on natural protein glycosylation machineries. PMID:24702330

  1. Hazardous organic compounds in biogas plant end products--soil burden and risk to food safety.

    PubMed

    Suominen, K; Verta, M; Marttinen, S

    2014-09-01

    The end products (digestate, solid fraction of the digestate, liquid fraction of the digestate) of ten biogas production lines in Finland were analyzed for ten hazardous organic compounds or compound groups: polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCB(7)), polyaromatic hydrocarbons (PAH(16)), bis-(2-ethylhexyl) phthalate (DEHP), perfluorinated alkyl compounds (PFCs), linear alkylbenzene sulfonates (LASs), nonylphenols and nonylphenol ethoxylates (NP+NPEOs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA). Biogas plant feedstocks were divided into six groups: municipal sewage sludge, municipal biowaste, fat, food industry by-products, animal manure and others (consisting of milling by-products (husk) and raw former foodstuffs of animal origin from the retail trade). There was no clear connection between the origin of the feedstocks of a plant and the concentrations of hazardous organic compounds in the digestate. For PCDD/Fs and for DEHP, the median soil burden of the compound after a single addition of digestate was similar to the annual atmospheric deposition of the compound or compound group in Finland or other Nordic countries. For PFCs, the median soil burden was somewhat lower than the atmospheric deposition in Finland or Sweden. For NP+NPEOs, the soil burden was somewhat higher than the atmospheric deposition in Denmark. The median soil burden of PBDEs was 400 to 1000 times higher than the PBDE air deposition in Finland or in Sweden. With PBDEs, PFCs and HBCD, the impact of the use of end products should be a focus of further research. Highly persistent compounds, such as PBDE- and PFC-compounds may accumulate in agricultural soil after repeated use of organic fertilizers containing these compounds. For other compounds included in this study, agricultural use of biogas plant end products is unlikely to cause risk to food safety in Finland. PMID:24593894

  2. Glycosylation-Based Serum Biomarkers for Cancer Diagnostics and Prognostics

    PubMed Central

    Kirwan, Alan; Utratna, Marta; O'Dwyer, Michael E.; Joshi, Lokesh; Kilcoyne, Michelle

    2015-01-01

    Cancer is the second most common cause of death in developed countries with approximately 14 million newly diagnosed individuals and over 6 million cancer-related deaths in 2012. Many cancers are discovered at a more advanced stage but better survival rates are correlated with earlier detection. Current clinically approved cancer biomarkers are most effective when applied to patients with widespread cancer. Single biomarkers with satisfactory sensitivity and specificity have not been identified for the most common cancers and some biomarkers are ineffective for the detection of early stage cancers. Thus, novel biomarkers with better diagnostic and prognostic performance are required. Aberrant protein glycosylation is well known hallmark of cancer and represents a promising source of potential biomarkers. Glycoproteins enter circulation from tissues or blood cells through active secretion or leakage and patient serum is an attractive option as a source for biomarkers from a clinical and diagnostic perspective. A plethora of technical approaches have been developed to address the challenges of glycosylation structure detection and determination. This review summarises currently utilised glycoprotein biomarkers and novel glycosylation-based biomarkers from the serum glycoproteome under investigation as cancer diagnostics and for monitoring and prognostics and includes details of recent high throughput and other emerging glycoanalytical techniques. PMID:26509158

  3. Effects of end products on fermentation profiles in Clostridium carboxidivorans P7 for syngas fermentation.

    PubMed

    Zhang, Jie; Taylor, Steven; Wang, Yi

    2016-10-01

    Clostridium carboxidivorans P7 is a strict anaerobic bacterium capable of converting syngas to biofuels. However, its fermentation profiles is poorly understood. Here, various end-products, including acetic acid, butyric acid, hexanoic acid, ethanol and butanol were supplemented to evaluate their effects on fermentation profiles in C. carboxidivorans at two temperatures. At 37°C, fatty acids addition likely led to more corresponding alcohols production. At 25°C, C2 and C4 fatty acids supplementation resulted in more corresponding higher fatty acids, while supplemented hexanoic acid increased yields of C2 and C4 fatty acids and hexanol. Supplementation of ethanol or butanol caused increased production of C2 and C4 acids at both temperatures; however, long-chain alcohols were still more likely produced at lower temperature. In conclusion, fermentation profiles of C. carboxidivorans can be changed in respond to pre-added end-products and carbon flow may be redirected to desired products by controlling culture conditions. PMID:27459682

  4. Conformational implications of asparagine-linked glycosylation.

    PubMed Central

    Imperiali, B; Rickert, K W

    1995-01-01

    The effects of cotranslational protein modification on the process of protein folding are poorly understood. Time-resolved fluorescence energy transfer has been used to assess the impact of glycosylation on the conformational dynamics of flexible oligopeptides. The peptide sequences examined are selected from glycoproteins of known three-dimensional structure. The energy transfer modulation associated with N-linked glycosylation is consistent with the glycopeptides sampling different conformational profiles in water. Results show that glycosylation causes the modified peptides to adopt a different ensemble of conformations, and for some peptides this change may lead to conformations that are more compact and better approximate the conformation of these peptides in the final folded protein. This result further implies that cotranslational glycosylation can trigger the timely formation of structural nucleation elements and thus assist in the complex process of protein folding. PMID:7816856

  5. [Glycosylation of autoantibodies in autoimmunes diseases].

    PubMed

    Goulabchand, R; Batteux, F; Guilpain, P

    2013-12-01

    Protein glycosylation is one of the most common post-translational modifications, involved in the well described protein biosynthesis process. Protein glycosylation seems to play a major role in the pathogenesis of auto-immune diseases. Herein are described the main alterations of autoantibody glycosylation associated with autoimmunes diseases such as rheumatoid arthritis, IgA glomerulonephritis, Schoenlein-Henoch purpura, Sjögren's syndrome, systemic scleroderma, systemic lupus erythematosus, myasthenia gravis and granulomatosis with polyangiitis (Wegener). Molecular identification of altered immunoglobulin glycosylation could lead to a better understanding of the pathogenesis of those diseases, might allow an evaluation of their biological activity and could even be a new therapeutic target. PMID:24139501

  6. Harnessing Glycosylation to Improve Cellulase Activity

    SciTech Connect

    Beckham, G. T.; Dai, Z.; Matthews, J. F.; Momany, M.; Payne, C. M.; Adney, W. S.; Baker, S. E.; Himmel, M. E.

    2012-06-01

    Cellulases and hemicellulases are responsible for the turnover of plant cell wall polysaccharides in the biosphere, and thus form the foundation of enzyme engineering efforts in biofuels research. Many of these carbohydrate-active enzymes from filamentous fungi contain both N-linked and O-linked glycosylation, the extent and heterogeneity of which depends on growth conditions, expression host, and the presence of glycan trimming enzymes in the secretome, all of which in turn impact enzyme activity. As the roles of glycosylation in enzyme function have not been fully elucidated, here we discuss the potential roles of glycosylation on glycoside hydrolase enzyme structure and function after secretion. We posit that glycosylation, instead of hindering cellulase engineering, can be used as an additional tool to enhance enzyme activity, given deeper understanding of its molecular-level role in biomass deconstruction.

  7. Harnessing glycosylation to improve cellulase activity

    SciTech Connect

    Beckham, Gregg T.; Dai, Ziyu; Mattews, James F.; Momany, Michelle; Payne, Christina M.; Adney, William S.; Baker, Scott E.; Himmel, Michael E.

    2012-06-11

    Cellulases and hemicellulases are responsible for the turnover of plant cell wall polysaccharides in the biosphere, and thus form the foundation of enzyme engineering efforts in biofuels research. Many of these carbohydrate-active enzymes from filamentous fungi contain both N-linked and O-linked glycosylation, the extent and heterogeneity of which depends on growth conditions, expression host, and the presence of glycan trimming enzymes in the secretome, all of which in turn impacts enzyme activity. As the roles of glycosylation in enzyme function have not been fully elucidated, here we discuss the potential roles of glycosylation on glycoside hydrolase enzyme structure and function after secretion. We posit that glycosylation, instead of hindering cellulase engineering, can be used as an additional tool to enhance enzyme activity, given deeper understanding of its molecular-level role in biomass deconstruction.

  8. End products of glucose and glutamine metabolism by L929 cells.

    PubMed

    Lanks, K W

    1987-07-25

    Products of glucose and glutamine metabolism by L929 cells were detected and quantitated by gas chromatography and mass spectrometry of the oxime-trimethylsilyl derivatives. This method allowed detection and identification of all major carboxylic and amino acids produced in the system. Although lactic acid was expected to be the major product, alanine, citric, glutamic, aspartic, and pyruvic acids were also released into the culture medium at significant rates. Incorporation of labeled carbon from D-[U-13C]glucose showed that the alanine, lactic, and pyruvic acids were derived from glucose as was one-third of the citric acid carbon. The rate of glucose utilization for production of these end products was 29-fold greater than the rate of glucose oxidation to CO2, and calculated ATP production from alanine and pyruvate synthesis exceeded that from lactate synthesis by nearly 2-fold. Utilization of glutamine for synthesis of aspartic, glutamic, and citric acids also exceeded the rate of glutamine oxidation, thereby making end-product synthesis from glucose and glutamine the dominant cellular metabolic activity. In the absence of glucose, synthesis and intracellular levels of aspartic and glutamic acids increased, whereas synthesis and cell content of the other acids decreased markedly. This response is consistent with the metabolic pattern proposed by Moreadith and Lehninger (Moreadith, R.W., and Lehninger, A.L. (1984) J. Biol. Chem. 259, 6215-6221) in which much of the glutamine used by these cells is converted to aspartate in the absence of a pyruvate source and to aspartate or citrate in the presence of pyruvate. PMID:3611053

  9. Epithelial Mesenchymal Transition Induces Aberrant Glycosylation through Hexosamine Biosynthetic Pathway Activation.

    PubMed

    Lucena, Miguel C; Carvalho-Cruz, Patricia; Donadio, Joana L; Oliveira, Isadora A; de Queiroz, Rafaela M; Marinho-Carvalho, Monica M; Sola-Penna, Mauro; de Paula, Iron F; Gondim, Katia C; McComb, Mark E; Costello, Catherine E; Whelan, Stephen A; Todeschini, Adriane R; Dias, Wagner B

    2016-06-17

    Deregulated cellular metabolism is a hallmark of tumors. Cancer cells increase glucose and glutamine flux to provide energy needs and macromolecular synthesis demands. Several studies have been focused on the importance of glycolysis and pentose phosphate pathway. However, a neglected but very important branch of glucose metabolism is the hexosamine biosynthesis pathway (HBP). The HBP is a branch of the glucose metabolic pathway that consumes ∼2-5% of the total glucose, generating UDP-GlcNAc as the end product. UDP-GlcNAc is the donor substrate used in multiple glycosylation reactions. Thus, HBP links the altered metabolism with aberrant glycosylation providing a mechanism for cancer cells to sense and respond to microenvironment changes. Here, we investigate the changes of glucose metabolism during epithelial mesenchymal transition (EMT) and the role of O-GlcNAcylation in this process. We show that A549 cells increase glucose uptake during EMT, but instead of increasing the glycolysis and pentose phosphate pathway, the glucose is shunted through the HBP. The activation of HBP induces an aberrant cell surface glycosylation and O-GlcNAcylation. The cell surface glycans display an increase of sialylation α2-6, poly-LacNAc, and fucosylation, all known epitopes found in different tumor models. In addition, modulation of O-GlcNAc levels was demonstrated to be important during the EMT process. Taken together, our results indicate that EMT is an applicable model to study metabolic and glycophenotype changes during carcinogenesis, suggesting that cell glycosylation senses metabolic changes and modulates cell plasticity. PMID:27129262

  10. Carbohydrate post-glycosylational modifications

    PubMed Central

    Yu, Hai; Chen, Xi

    2008-01-01

    Carbohydrate modification is a common phenomenon in nature. Many carbohydrate modifications such as some epimerization, O-acetylation, O-sulfation, O-methylation, N-deacetylation, and N-sulfation, take place after the formation of oligosaccharide or polysaccharide backbones. These modifications can be categorized as carbohydrate post-glycosylational modifications (PGMs). Carbohydrate PGMs further extend the complexity of the structures and the synthesis of carbohydrates and glycoconjugates. They also increase the capacity of the biological information that can be controlled by finely tuning the structures of carbohydrates. Developing efficient methods to obtain structurally defined naturally occurring oligosaccharides, polysaccharides, and glycoconjugates with carbohydrate PGMs is essential for understanding the biological significance of carbohydrate PGMs. Combine with high-throughput screening methods, synthetic carbohydrates with PGMs are invaluable probes in structure-activity relationship studies. We illustrate here several classes of carbohydrates with PGMs and their applications. Recent progress in chemical, enzymatic, and chemoenzymatic syntheses of these carbohydrates and their derivatives are also presented. PMID:17340000

  11. N-/O-glycosylation analysis of human FVIIa produced in the milk of transgenic rabbits

    PubMed Central

    Chevreux, Guillaume; Faid, Valegh; Scohyers, Jean-Marc; Bihoreau, Nicolas

    2013-01-01

    Human coagulation factor VIIa is a glycoprotein that promotes haemostasis through activation of the coagulation cascade extrinsic pathway. Most haemophilia A/B patients with inhibitors are treated by injection of plasma-derived or recombinant FVIIa. The use of recombinant products raises questions about the ability of the host cell to produce efficiently post-translationally modified proteins. Glycosylation is especially critical considering that it can modulate protein safety and efficacy. The present paper reports the N-/O-glycosylation pattern of a new recombinant human factor VIIa expressed in the mammary glands of transgenic rabbits. Glycosylation was investigated by chromatography and advanced mass spectrometry techniques for glycan identification and quantitation. Mass spectrometry (MS)/MS analyses were performed to confirm the glycan structures as well as the position and branching of specific monosaccharides or substituents. The two N-glycosylation sites were found to be fully occupied mostly by mono- and bi-sialylated biantennary complex-type structures, the major form being A2G2S1. Some oligomannose/hybrid structures were retrieved in lower abundance, the major ones being GlcNAcα1,O-phosphorylated at the C6-position of a Man residue (Man-6-(GlcNAcα1,O-)phosphate motif) as commonly observed on lysosomal proteins. No immunogenic glycotopes such as Galili (Galα1,3Gal) and HD antigens (N-glycolylneuraminic acid (NeuGc)) were detected. Concerning O-glycosylation, the product exhibited O-fucose and O-glucose-(xylose)0, 1, 2 motifs as expected. The N-glycosylation consistency was also investigated by varying production parameters such as the period of lactation, the number of consecutive lactations and rabbit generations. Results show that the transgenesis technology is suitable for the long-term production of rhFVIIa with a reproducible glycosylation pattern. PMID:24092837

  12. Carbohydrates on Proteins: Site-Specific Glycosylation Analysis by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zhu, Zhikai; Desaire, Heather

    2015-07-01

    Glycosylation on proteins adds complexity and versatility to these biologically vital macromolecules. To unveil the structure-function relationship of glycoproteins, glycopeptide-centric analysis using mass spectrometry (MS) has become a method of choice because the glycan is preserved on the glycosylation site and site-specific glycosylation profiles of proteins can be readily determined. However, glycopeptide analysis is still challenging given that glycopeptides are usually low in abundance and relatively difficult to detect and the resulting data require expertise to analyze. Viewing the urgent need to address these challenges, emerging methods and techniques are being developed with the goal of analyzing glycopeptides in a sensitive, comprehensive, and high-throughput manner. In this review, we discuss recent advances in glycoprotein and glycopeptide analysis, with topics covering sample preparation, analytical separation, MS and tandem MS techniques, as well as data interpretation and automation.

  13. SweetBac: Applying MultiBac Technology Towards Flexible Modification of Insect Cell Glycosylation.

    PubMed

    Palmberger, Dieter; Rendic, Dubravko

    2015-01-01

    Observed different glycosylation patterns of glycoconjugates (recombinantly) produced in various eukaryotic organisms are a direct consequence of differences in numerous proteins involved in biosynthesis of the relevant glycan chains in these species. The need for efficient, robust and flexible methods for recombinant expression of proteins is met by the recently described MultiBac technology, an advanced and optimized baculovirus-based system for simultaneous recombinant protein expression in insect cells. A derivative of MultiBac technology, the SweetBac system aims at the modification of the glycosylation potential of insect cells as expression hosts. The application of SweetBac, including the methods needed to investigate the glycosylation pattern of the purified recombinant protein, is described in this chapter. PMID:26082221

  14. Mucin glycosylating enzyme GALNT2 suppresses malignancy in gastric adenocarcinoma by reducing MET phosphorylation

    PubMed Central

    Liu, Shin-Yun; Shun, Chia-Tung; Hung, Kuan-Yu; Juan, Hsueh-Fen; Hsu, Chia-Lang; Huang, Min-Chuan; Lai, I-Rue

    2016-01-01

    Glycosylation affects malignancy in cancer. Here, we report that N- acetylgalactosaminyltransferase 2 (GALNT2), an enzyme that mediates the initial step of mucin type-O glycosylation, suppresses malignant phenotypes in gastric adenocarcinoma (GCA) by modifying MET (Hepatocyte growth factor receptor) activity. GALNT2 mRNA and protein were downregulated in GCAs, and this reduction was associated with more advanced disease stage and shorter recurrence-free survival. Suppressing GALNT2 expression in GCA cells increased cell growth, migration, and invasion in vitro, and tumor metastasis in vivo. GALNT2 knockdown enhanced phosphorylation of MET and decreased expression of the Tn antigen on MET. Inhibiting MET activity with PHA665752 decreased the malignant phenotypes caused by GALNT2 knockdown in GCA cells. Our results indicate that GALNT2 suppresses the malignant potential of GCA cells and provide novel insights into the significance of O-glycosylation in MET activity and GCA progression. PMID:26848976

  15. Co-composting of eggshell waste in self-heating reactors: monitoring and end product quality.

    PubMed

    Soares, Micaela A R; Quina, Margarida M J; Quinta-Ferreira, Rosa M

    2013-11-01

    Industrial eggshell waste (ES) is classified as an animal by-product not intended to human consumption. For reducing pathogen spreading risk due to soil incorporation of ES, sanitation by composting is a pre-treatment option. This work aims to evaluate eggshell waste recycling in self-heating composting reactors and investigate ES effect on process evolution and end product quality. Potato peel, grass clippings and rice husks were the starting organic materials considered. The incorporation of 30% (w/w) ES in a composting mixture did not affect mixture biodegradability, nor its capacity to reach sanitizing temperatures. After 25 days of composting, ES addition caused a nitrogen loss of about 10 g N kg(-1) of initial volatile solids, thus reducing nitrogen nutritional potential of the finished compost. This study showed that a composting mixture with a significant proportion of ES (30% w/w) may be converted into calcium-rich marketable compost to neutralize soil acidity and/or calcium deficiencies. PMID:24055972

  16. Strategies to reduce end-product inhibition in family 48 glycoside hydrolases

    DOE PAGESBeta

    Chen, Mo; Bu, Lintao; Alahuhta, Markus; Brunecky, Roman; Xu, Qi; Lunin, Vladimir V.; Brady, John W.; Crowley, Michael F.; Himmel, Michael E.; Bomble, Yannick J.

    2016-02-01

    Family 48 cellobiohydrolases are some of the most abundant glycoside hydrolases in nature. They are able to degrade cellulosic biomass and therefore serve as good enzyme candidates for biofuel production. Family 48 cellulases hydrolyze cellulose chains via a processive mechanism, and produce end products composed primarily of cellobiose as well as other cellooligomers (dp ≤ 4). The challenge of utilizing cellulases in biofuel production lies in their extremely slow turnover rate. A factor contributing to the low enzyme activity is suggested to be product binding to enzyme and the resulting performance inhibition. In this study, we quantitatively evaluated the productmore » inhibitory effect of four family 48 glycoside hydrolases using molecular dynamics simulations and product expulsion free-energy calculations. We also suggested a series of single mutants of the four family 48 glycoside hydrolases with theoretically reduced level of product inhibition. As a result, the theoretical calculations provide a guide for future experimental studies designed to produce mutant cellulases with enhanced activity.« less

  17. Glycosylation as a marker for inflammatory arthritis.

    PubMed

    Albrecht, Simone; Unwin, Louise; Muniyappa, Mohankumar; Rudd, Pauline M

    2014-01-01

    Changes in serum protein glycosylation play an important role in inflammatory arthritis. Altered galactosylation of immunoglobulin G (IgG) in rheumatoid arthritis attracts special attention due to the devastating nature of the disease. Studying glycosylation changes of serum proteins has been recognized as a potential strategy to provide added value regarding diagnostics, aetiopathology and therapy of inflammatory arthritic diseases. Key questions, which are approached in these fields of research, are whether or not glycosylation can be used as a complementary pre-clinical and clinical marker for disease differentiation, diagnosis, the prediction of disease course and severity as well as for the evaluation of disease therapies. These studies mainly focus on TNF antagonists, which present a new and promising way of treating inflammatory arthritis. The recent availability of new high-throughput glycoanalytical tools enables a more profound and efficient investigation in large patient cohorts and helps to gain new insights in the complex mechanism of the underlying disease pathways. PMID:24643039

  18. Glycoprotein Structural Genomics: Solving the Glycosylation Problem

    PubMed Central

    Chang, Veronica T.; Crispin, Max; Aricescu, A. Radu; Harvey, David J.; Nettleship, Joanne E.; Fennelly, Janet A.; Yu, Chao; Boles, Kent S.; Evans, Edward J.; Stuart, David I.; Dwek, Raymond A.; Jones, E. Yvonne; Owens, Raymond J.; Davis, Simon J.

    2007-01-01

    Summary Glycoproteins present special problems for structural genomic analysis because they often require glycosylation in order to fold correctly, whereas their chemical and conformational heterogeneity generally inhibits crystallization. We show that the “glycosylation problem” can be solved by expressing glycoproteins transiently in mammalian cells in the presence of the N-glycosylation processing inhibitors, kifunensine or swainsonine. This allows the correct folding of the glycoproteins, but leaves them sensitive to enzymes, such as endoglycosidase H, that reduce the N-glycans to single residues, enhancing crystallization. Since the scalability of transient mammalian expression is now comparable to that of bacterial systems, this approach should relieve one of the major bottlenecks in structural genomic analysis. PMID:17355862

  19. Large-Scale Organization of Glycosylation Networks

    NASA Astrophysics Data System (ADS)

    Kim, Pan-Jun; Lee, Dong-Yup; Jeong, Hawoong

    2009-03-01

    Glycosylation is a highly complex process to produce a diverse repertoire of cellular glycans that are frequently attached to proteins and lipids. Glycans participate in fundamental biological processes including molecular trafficking and clearance, cell proliferation and apoptosis, developmental biology, immune response, and pathogenesis. N-linked glycans found on proteins are formed by sequential attachments of monosaccharides with the help of a relatively small number of enzymes. Many of these enzymes can accept multiple N-linked glycans as substrates, thus generating a large number of glycan intermediates and their intermingled pathways. Motivated by the quantitative methods developed in complex network research, we investigate the large-scale organization of such N-glycosylation pathways in a mammalian cell. The uncovered results give the experimentally-testable predictions for glycosylation process, and can be applied to the engineering of therapeutic glycoproteins.

  20. Exploring the Glycosylation of Serum CA125

    PubMed Central

    Saldova, Radka; Struwe, Weston B.; Wynne, Kieran; Elia, Giuliano; Duffy, Michael J.; Rudd, Pauline M.

    2013-01-01

    Ovarian cancer is the most lethal gynaecologic cancer affecting women. The most widely used biomarker for ovarian cancer, CA125, lacks sensitivity and specificity. Here, we explored differences in glycosylation of CA125 between serum from patients with ovarian cancer and healthy controls. We found differences between CA125 N-glycans from patient sera compared to controls. These include increases in core-fucosylated bi-antennary monosialylated glycans, as well as decreases in mostly bisecting bi-antennary and non-fucosylated glycans in patients compared to controls. Measurement of the glycosylated state of CA125 may therefore provide a more specific biomarker for patients with ovarian cancer. PMID:23896595

  1. Sorption of biodegradation end products of nonylphenol polyethoxylates onto activated sludge.

    PubMed

    Hung, Nguyen Viet; Tateda, Masafumi; Ike, Michihiko; Fujita, Masanori; Tsunoi, Shinji; Tanaka, Minoru

    2004-01-01

    Nonylphenol(NP), nonylphenoxy acetic acid (NP1EC), nonylphenol monoethoxy acetic acid (NP2EC), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) are biodegradation end products (BEPs) of nonionic surfactant nonylphenolpolyethoxylates (NPnEO). In this research, sorption of these compounds onto model activated sludge was characterized. Sorption equilibrium experiments showed that NP, NP1EO and NP2EO reached equilibrium in about 12 h, while equilibrium of NP1EC and NP2EC were reached earlier, in about 4 h. In sorption isotherm experiments, obtained equilibrium data at 28 degrees C fitted well to Freundlich sorption model for all investigated compounds. For NP1EC, in addition to Freundlich, equilibrium data also fitted well to Langmuir model. Linear sorption model was also tried, and equilibrium data of all NP, NP1EO, NP2EO and NP2EC except NP1EC fitted well to this model. Calculated Freundlich coefficient (K(F)) and linear sorption coefficient (K(D)) showed that sorption capacity of the investigated compounds were in order NP > NP2EO > NP1EO > NP1EC approximately NP2EC. For NP, NP1EO and NP2EO, high values of calculated K(F) and K(D) indicated an easy uptake of these compounds from aqueous phase onto activated sludge. Whereas, NP1EC and NP2EC with low values of K(F) and K(D) absorbed weakly to activated sludge and tended to preferably remain in aqueous phase. PMID:15495957

  2. Modulation of keratinocyte expression of antioxidants by 4-hydroxynonenal, a lipid peroxidation end product

    PubMed Central

    Zheng, Ruijin; Heck, Diane E.; Mishin, Vladimir; Black, Adrienne T.; Shakarjian, Michael P.; Kong, Ah-Ng Tony; Laskin, Debra L.; Laskin, Jeffrey D.

    2014-01-01

    4-Hydroxynonenal (4-HNE) is a lipid peroxidation end product generated in response to oxidative stress in the skin. Keratinocytes contain an array of antioxidant enzymes which protect against oxidative stress. In these studies, we characterized 4-HNE-induced changes in antioxidant expression in mouse keratinocytes. Treatment of primary mouse keratinocytes and PAM 212 keratinocytes with 4-HNE increased mRNA expression for heme oxygenase-1 (HO-1), catalase, NADPH:quinone oxidoreductase (NQO1) and glutathione S-transferase (GST) A1-2, GSTA3 and GSTA4. In both cell types, HO-1 was the most sensitive, increasing 86-98 fold within 6 h. Further characterization of the effects of 4-HNE on HO-1 demonstrated concentration- and time-dependent increases in mRNA and protein expression which were maximum after 6 h with 30 μM. 4-HNE stimulated keratinocyte Erk1/2, JNK and p38 MAP kinases, as well as PI3 kinase. Inhibition of these enzymes suppressed 4-HNE-induced HO-1 mRNA and protein expression. 4-HNE also activated Nrf2 by inducing its translocation to the nucleus. 4-HNE was markedly less effective in inducing HO-1 mRNA and protein in keratinocytes from Nrf2−/− mice, when compared to wild type mice, indicating that Nrf2 also regulates 4-HNE-induced signaling. Western blot analysis of caveolar membrane fractions isolated by sucrose density centrifugation demonstrated that 4-HNE-induced HO-1 is localized in keratinocyte caveolae. Treatment of the cells with methyl-β-cyclodextrin, which disrupts caveolar structure, suppressed 4-HNE-induced HO-1. These findings indicate that 4-HNE modulates expression of antioxidant enzymes in keratinocytes, and that this can occur by different mechanisms. Changes in expression of keratinocyte antioxidants may be important in protecting the skin from oxidative stress. PMID:24423726

  3. N-Linked Glycosylation in Archaea: a Structural, Functional, and Genetic Analysis

    PubMed Central

    Ding, Yan; Meyer, Benjamin H.; Albers, Sonja-Verena; Kaminski, Lina; Eichler, Jerry

    2014-01-01

    SUMMARY N-glycosylation of proteins is one of the most prevalent posttranslational modifications in nature. Accordingly, a pathway with shared commonalities is found in all three domains of life. While excellent model systems have been developed for studying N-glycosylation in both Eukarya and Bacteria, an understanding of this process in Archaea was hampered until recently by a lack of effective molecular tools. However, within the last decade, impressive advances in the study of the archaeal version of this important pathway have been made for halophiles, methanogens, and thermoacidophiles, combining glycan structural information obtained by mass spectrometry with bioinformatic, genetic, biochemical, and enzymatic data. These studies reveal both features shared with the eukaryal and bacterial domains and novel archaeon-specific aspects. Unique features of N-glycosylation in Archaea include the presence of unusual dolichol lipid carriers, the use of a variety of linking sugars that connect the glycan to proteins, the presence of novel sugars as glycan constituents, the presence of two very different N-linked glycans attached to the same protein, and the ability to vary the N-glycan composition under different growth conditions. These advances are the focus of this review, with an emphasis on N-glycosylation pathways in Haloferax, Methanococcus, and Sulfolobus. PMID:24847024

  4. [Fragment of Receptor for Advanced Glycation End Products Improves Memory State in a Model of Alzheimer's Disease].

    PubMed

    Volpina, O M; Koroev, D O; Volkova, T D; Kamynina, A V; Filatova, M P; Zaporozhskayva, Y V; Samokhin, A N; Aleksandrova, I J; Bobkova, N V

    2015-01-01

    A number of synthetic peptides corresponding to potentially important regions in the sequence of the four membrane proteins known as beta-amyloid cell receptors have been investigated on their ability to improve memory state in experimental model of Alzheimer's disease. Nine fragments repeating all the exposed nonstructural regions of the RAGE protein according to X-ray data, have been synthesized. The activity of these peptides and synthesized earlier immunoprotective fragments of other three proteins (acetylcholine receptor alpha7-type, prion protein and neurotrophin receptor p75) has been investigated under intranasal administration, without immune response to the peptide. Only one fragment RAGE (60-76) was shown to have a therapeutic activity improving the memory state of bulbectomized mice and leads to decreasing in the level of brain beta-amyloid. PMID:27125025

  5. Oat Protects against Diabetic Nephropathy in Rats via Attenuating Advanced Glycation End Products and Nuclear Factor Kappa B

    PubMed Central

    Al-Malki, Abdulrahman L.

    2013-01-01

    Oat, a rich source of soluble fiber, was considered to have a possible preventive effect on the progression of diabetic nephropathy. The present study aimed to assess this preventive activity in a rat model of diabetic nephropathy. Adult Wister rats were injected by streptozotocin (65 mg/kg). Animals were fed with normal diet or with a diet containing 20% oat (W/W) for 21 weeks. At the end of 21 weeks, all the kidney tissues were collected for various examinations. Our results suggested that oat could decrease the Scr and glucose level in blood of diabetic rats significantly (P < 0.05), and increase the creatinine clearance (P < 0.01). In histopathological examination, oat-fed rats showed a significant decrease in glomerulus segmented sclerosis and incidence of tubule vacuolar degeneration. By ELISA, we reported that oat feeding resulted in decreasing the levels of IL-6 and AGE in serum and kidney homogenate. In addition, the levels of oxidative stress markers were markedly improved as a result of oat feeding. Furthermore, using EMSA, we showed that oat attenuated the activation of NF-κB. Using RT-PCR, we found that oat could downregulate the TGF-β1 and RAGE expression at mRNA levels. This study suggests that oat can suppress diabetic nephropathy in rats effectively and may slow down the renal fibrosis by the disruption of the detrimental AGE-RAGE-NFκB axis. PMID:24223616

  6. Toxicological evaluation of advanced glycation end product Nε-(carboxymethyl)lysine: Acute and subacute oral toxicity studies.

    PubMed

    Liu, Xin; Zheng, Liangqing; Zhang, Rong; Liu, Gang; Xiao, Shensheng; Qiao, Xiaoting; Wu, Yongning; Gong, Zhiyong

    2016-06-01

    Nε-(carboxymethyl)lysine (CML) as a novel potential noxious compound in various food products has aroused extensive concern in recent years. This study aimed to investigate the oral acute and subacute toxicity of CML in mice as per OECD 420 and 407 guidelines. Acute administration of 2000 and 5000 mg/kg CML did not induce any mortality within 14 days, nevertheless some toxicological symptoms and histopathological changes were observed. The estimated LD50 of CML was >5000 mg/kg. In subacute toxicity test, CML was dosed at 200, 500 and 1000 mg/kg in both genders for 28 days. The body weights reduced which was accompanied with the decrease of food consumptions. Hematology parameters viz. RBC, HGB and MCH showed minor alteration but these were still within normal range. Biochemical analysis of hepatic and renal function markers showed significant elevating in AST, ALT, Cr and BUN etc. Histopathological alterations were observed in lung, liver, kidney and spleen. Subacute toxicity of CML involved oxidative stress caused by reducing antioxidant enzyme (SOD and GSH-Px) activities, and significantly increasing lipid peroxide (MDA) level. In conclusion, CML was unlikely to present an acute hazard, but repeated administration could produce deleterious effects on mice especially inducing liver and kidney damage through oxidative stress. PMID:26921796

  7. The Autonomous Glycosylation of Large DNA Viruses.

    PubMed

    Piacente, Francesco; Gaglianone, Matteo; Laugieri, Maria Elena; Tonetti, Michela G

    2015-01-01

    Glycosylation of surface molecules is a key feature of several eukaryotic viruses, which use the host endoplasmic reticulum/Golgi apparatus to add carbohydrates to their nascent glycoproteins. In recent years, a newly discovered group of eukaryotic viruses, belonging to the Nucleo-Cytoplasmic Large DNA Virus (NCLDV) group, was shown to have several features that are typical of cellular organisms, including the presence of components of the glycosylation machinery. Starting from initial observations with the chlorovirus PBCV-1, enzymes for glycan biosynthesis have been later identified in other viruses; in particular in members of the Mimiviridae family. They include both the glycosyltransferases and other carbohydrate-modifying enzymes and the pathways for the biosynthesis of the rare monosaccharides that are found in the viral glycan structures. These findings, together with genome analysis of the newly-identified giant DNA viruses, indicate that the presence of glycogenes is widespread in several NCLDV families. The identification of autonomous viral glycosylation machinery leads to many questions about the origin of these pathways, the mechanisms of glycan production, and eventually their function in the viral replication cycle. The scope of this review is to highlight some of the recent results that have been obtained on the glycosylation systems of the large DNA viruses, with a special focus on the enzymes involved in nucleotide-sugar production. PMID:26690138

  8. Detection of cytoplasmic glycosylation associated with hydroxyproline.

    PubMed

    West, Christopher M; van der Wel, Hanke; Blader, Ira J

    2006-01-01

    A special class of glycosylation occurs on a proline residue of the cytoplasmic/nuclear protein Skp1 in the social amoeba Dictyostelium. For this glycosylation to occur, the proline must first be hydroxylated by the action of a soluble prolyl 4-hydroxylase acting on the protein. Cytoplasmic prolyl 4-hydroxylases are dioxygen-dependent enzymes that have low affinity for their O2 substrate and, therefore, have been implicated in O2-sensing in Dictyostelium, as well as in vertebrates and invertebrates. The sugar-hydroxyproline linkage has low abundance, is resistant to alkali cleavage and known glycosidases, and does not bind known lectins. However, initial screens for this modification can be made by assessing changes in electrophoretic mobility of candidate proteins after treatment of cells with prolyl hydroxylase inhibitors, and/or by metabolic labeling with [3H]sugar precursors. In addition, cytoplasmic hydroxylation/glycosylation can be assessed by assaying for cytoplasmic glycosyltransferases. Here we describe these methods and examples of their use in analyzing Skp1 glycosylation in Dictyostelium and the apicomplexan Toxoplasma gondii, the causative agent of toxoplasmosis in humans. PMID:17132515

  9. The Autonomous Glycosylation of Large DNA Viruses

    PubMed Central

    Piacente, Francesco; Gaglianone, Matteo; Laugieri, Maria Elena; Tonetti, Michela G.

    2015-01-01

    Glycosylation of surface molecules is a key feature of several eukaryotic viruses, which use the host endoplasmic reticulum/Golgi apparatus to add carbohydrates to their nascent glycoproteins. In recent years, a newly discovered group of eukaryotic viruses, belonging to the Nucleo-Cytoplasmic Large DNA Virus (NCLDV) group, was shown to have several features that are typical of cellular organisms, including the presence of components of the glycosylation machinery. Starting from initial observations with the chlorovirus PBCV-1, enzymes for glycan biosynthesis have been later identified in other viruses; in particular in members of the Mimiviridae family. They include both the glycosyltransferases and other carbohydrate-modifying enzymes and the pathways for the biosynthesis of the rare monosaccharides that are found in the viral glycan structures. These findings, together with genome analysis of the newly-identified giant DNA viruses, indicate that the presence of glycogenes is widespread in several NCLDV families. The identification of autonomous viral glycosylation machinery leads to many questions about the origin of these pathways, the mechanisms of glycan production, and eventually their function in the viral replication cycle. The scope of this review is to highlight some of the recent results that have been obtained on the glycosylation systems of the large DNA viruses, with a special focus on the enzymes involved in nucleotide-sugar production. PMID:26690138

  10. Muscular dystrophies due to glycosylation defects.

    PubMed

    Muntoni, Francesco; Torelli, Silvia; Brockington, Martin

    2008-10-01

    In the last few years, muscular dystrophies due to reduced glycosylation of alpha-dystroglycan (ADG) have emerged as a common group of conditions, now referred to as dystroglycanopathies. Mutations in six genes (POMT1, POMT2, POMGnT1, Fukutin, FKRP and LARGE) have so far been identified in patients with a dystroglycanopathy. Allelic mutations in each of these genes can result in a wide spectrum of clinical conditions, ranging from severe congenital onset with associated structural brain malformations (Walker Warburg syndrome; muscle-eye-brain disease; Fukuyama muscular dystrophy; congenital muscular dystrophy type 1D) to a relatively milder congenital variant with no brain involvement (congenital muscular dystrophy type 1C), and to limb-girdle muscular dystrophy (LGMD) type 2 variants with onset in childhood or adult life (LGMD2I, LGMD2L, and LGMD2N). ADG is a peripheral membrane protein that undergoes multiple and complex glycosylation steps to regulate its ability to effectively interact with extracellular matrix proteins, such as laminin, agrin, and perlecan. Although the precise composition of the glycans present on ADG are not known, it has been demonstrated that the forced overexpression of LARGE, or its paralog LARGE2, is capable of increasing the glycosylation of ADG in normal cells. In addition, its overexpression is capable of restoring dystroglycan glycosylation and laminin binding properties in primary cell cultures of patients affected by different genetically defined dystroglycanopathy variants. These observations suggest that there could be a role for therapeutic strategies to overcome the glycosylation defect in these conditions via the overexpression of LARGE. PMID:19019316

  11. Modulation of keratinocyte expression of antioxidants by 4-hydroxynonenal, a lipid peroxidation end product

    SciTech Connect

    Zheng, Ruijin; Heck, Diane E.; Mishin, Vladimir; Black, Adrienne T.; Shakarjian, Michael P.; Kong, Ah-Ng Tony; Laskin, Debra L.; Laskin, Jeffrey D.

    2014-03-01

    4-Hydroxynonenal (4-HNE) is a lipid peroxidation end product generated in response to oxidative stress in the skin. Keratinocytes contain an array of antioxidant enzymes which protect against oxidative stress. In these studies, we characterized 4-HNE-induced changes in antioxidant expression in mouse keratinocytes. Treatment of primary mouse keratinocytes and PAM 212 keratinocytes with 4-HNE increased mRNA expression for heme oxygenase-1 (HO-1), catalase, NADPH:quinone oxidoreductase (NQO1) and glutathione S-transferase (GST) A1-2, GSTA3 and GSTA4. In both cell types, HO-1 was the most sensitive, increasing 86–98 fold within 6 h. Further characterization of the effects of 4-HNE on HO-1 demonstrated concentration- and time-dependent increases in mRNA and protein expression which were maximum after 6 h with 30 μM. 4-HNE stimulated keratinocyte Erk1/2, JNK and p38 MAP kinases, as well as PI3 kinase. Inhibition of these enzymes suppressed 4-HNE-induced HO-1 mRNA and protein expression. 4-HNE also activated Nrf2 by inducing its translocation to the nucleus. 4-HNE was markedly less effective in inducing HO-1 mRNA and protein in keratinocytes from Nrf2 −/− mice, when compared to wild type mice, indicating that Nrf2 also regulates 4-HNE-induced signaling. Western blot analysis of caveolar membrane fractions isolated by sucrose density centrifugation demonstrated that 4-HNE-induced HO-1 is localized in keratinocyte caveolae. Treatment of the cells with methyl-β-cyclodextrin, which disrupts caveolar structure, suppressed 4-HNE-induced HO-1. These findings indicate that 4-HNE modulates expression of antioxidant enzymes in keratinocytes, and that this can occur by different mechanisms. Changes in expression of keratinocyte antioxidants may be important in protecting the skin from oxidative stress. - Highlights: • Lipid peroxidation generates 4-hydroxynonenal, a reactive aldehyde. • 4-HNE induces antioxidant proteins in mouse keratinocytes. • Induction of

  12. Sequence-based protein stabilization in the absence of glycosylation.

    PubMed

    Tan, Nikki Y; Bailey, Ulla-Maja; Jamaluddin, M Fairuz; Mahmud, S Halimah Binte; Raman, Suresh C; Schulz, Benjamin L

    2014-01-01

    Asparagine-linked N-glycosylation is a common modification of proteins that promotes productive protein folding and increases protein stability. Although N-glycosylation is important for glycoprotein folding, the precise sites of glycosylation are often not conserved between protein homologues. Here we show that, in Saccharomyces cerevisiae, proteins upregulated during sporulation under nutrient deprivation have few N-glycosylation sequons and in their place tend to contain clusters of like-charged amino-acid residues. Incorporation of such sequences complements loss of in vivo protein function in the absence of glycosylation. Targeted point mutation to create such sequence stretches at glycosylation sequons in model glycoproteins increases in vitro protein stability and activity. A dependence on glycosylation for protein stability or activity can therefore be rescued with a small number of local point mutations, providing evolutionary flexibility in the precise location of N-glycans, allowing protein expression under nutrient-limiting conditions, and improving recombinant protein production. PMID:24434425

  13. Solving Glycosylation Disorders: Fundamental Approaches Reveal Complicated Pathways

    PubMed Central

    Freeze, Hudson H.; Chong, Jessica X.; Bamshad, Michael J.; Ng, Bobby G.

    2014-01-01

    Over 100 human genetic disorders result from mutations in glycosylation-related genes. In 2013, a new glycosylation disorder was reported every 17 days. This trend will probably continue given that at least 2% of the human genome encodes glycan-biosynthesis and -recognition proteins. Established biosynthetic pathways provide many candidate genes, but finding unanticipated mutated genes will offer new insights into glycosylation. Simple glycobiomarkers can be used in narrowing the candidates identified by exome and genome sequencing, and those can be validated by glycosylation analysis of serum or cells from affected individuals. Model organisms will expand the understanding of these mutations’ impact on glycosylation and pathology. Here, we highlight some recently discovered glycosylation disorders and the barriers, breakthroughs, and surprises they presented. We predict that some glycosylation disorders might occur with greater frequency than current estimates of their prevalence. Moreover, the prevalence of some disorders differs substantially between European and African Americans. PMID:24507773

  14. Efficient synthesis of glycosylated phenazine natural products and analogs with DISAL (methyl 3,5-dinitrosalicylate) glycosyl donors.

    PubMed

    Laursen, Jane B; Petersen, Lars; Jensen, Knud J; Nielsen, John

    2003-09-21

    Inspired by the occurrence and function of phenazines in natural products, new glycosylated analogs were designed and synthesized. DISAL (methyl 3,5-dinitrosalicylate) glycosyl donors were used in an efficient and easily-handled glycosylation protocol compatible with combinatorial chemistry. Benzoylated D-glucose, D-galactose and L-quinovose DISAL glycosyl donors were synthesized in high yields and used under mild conditions to glycosylate methyl saphenate and 2-hydroxyphenazine. The glycosides were screened for biological activity and one compound showed inhibitory activity towards topoisomerase II. PMID:14527145

  15. Optimal Synthetic Glycosylation of a Therapeutic Antibody

    PubMed Central

    Parsons, Thomas B.; Struwe, Weston B.; Gault, Joseph; Yamamoto, Keisuke; Taylor, Thomas A.; Raj, Ritu; Wals, Kim; Mohammed, Shabaz; Benesch, Justin L. P.

    2016-01-01

    Abstract Glycosylation patterns in antibodies critically determine biological and physical properties but their precise control is a significant challenge in biology and biotechnology. We describe herein the optimization of an endoglycosidase‐catalyzed glycosylation of the best‐selling biotherapeutic Herceptin, an anti‐HER2 antibody. Precise MS analysis of the intact four‐chain Ab heteromultimer reveals nonspecific, non‐enzymatic reactions (glycation), which are not detected under standard denaturing conditions. This competing reaction, which has hitherto been underestimated as a source of side products, can now be minimized. Optimization allowed access to the purest natural form of Herceptin to date (≥90 %). Moreover, through the use of a small library of sugars containing non‐natural functional groups, Ab variants containing defined numbers of selectively addressable chemical tags (reaction handles at Sia C1) in specific positions (for attachment of cargo molecules or “glycorandomization”) were readily generated.

  16. Optimal Synthetic Glycosylation of a Therapeutic Antibody

    PubMed Central

    Parsons, Thomas B.; Struwe, Weston B.; Gault, Joseph; Yamamoto, Keisuke; Taylor, Thomas A.; Raj, Ritu; Wals, Kim; Mohammed, Shabaz; Benesch, Justin L. P.

    2016-01-01

    Abstract Glycosylation patterns in antibodies critically determine biological and physical properties but their precise control is a significant challenge in biology and biotechnology. We describe herein the optimization of an endoglycosidase‐catalyzed glycosylation of the best‐selling biotherapeutic Herceptin, an anti‐HER2 antibody. Precise MS analysis of the intact four‐chain Ab heteromultimer reveals nonspecific, non‐enzymatic reactions (glycation), which are not detected under standard denaturing conditions. This competing reaction, which has hitherto been underestimated as a source of side products, can now be minimized. Optimization allowed access to the purest natural form of Herceptin to date (≥90 %). Moreover, through the use of a small library of sugars containing non‐natural functional groups, Ab variants containing defined numbers of selectively addressable chemical tags (reaction handles at Sia C1) in specific positions (for attachment of cargo molecules or “glycorandomization”) were readily generated. PMID:26756880

  17. Involvement of Aberrant Glycosylation in Thyroid Cancer

    PubMed Central

    Miyoshi, Eiji; Ito, Yasuhiro; Miyoshi, Yoko

    2010-01-01

    Glycosylation is one of the most common posttranslational modification reactions and nearly half of all known proteins in eukaryotes are glycosylated. In fact, changes in oligosaccharides structures are associated with many physiological and pathological events, including cell growth, migration and differentiation, and tumor invasion. Therefore, functional glycomics, which is a comprehensive study of the structures and functions of glycans, is attracting the increasing attention of scientists in various fields of life science. In cases of thyroid cancer, the biological characters and prognosis are completely different in each type of histopathology, and their oligosaccharide structures as well as the expression of glycosyltransferases are also different. In this review, we summarized our previous papers on oligosaccharides and thyroid cancers and discussed a possible function of oligosaccharides in the carcinogenesis in thyroid cancer. PMID:20652009

  18. Optimal Synthetic Glycosylation of a Therapeutic Antibody.

    PubMed

    Parsons, Thomas B; Struwe, Weston B; Gault, Joseph; Yamamoto, Keisuke; Taylor, Thomas A; Raj, Ritu; Wals, Kim; Mohammed, Shabaz; Robinson, Carol V; Benesch, Justin L P; Davis, Benjamin G

    2016-02-01

    Glycosylation patterns in antibodies critically determine biological and physical properties but their precise control is a significant challenge in biology and biotechnology. We describe herein the optimization of an endoglycosidase-catalyzed glycosylation of the best-selling biotherapeutic Herceptin, an anti-HER2 antibody. Precise MS analysis of the intact four-chain Ab heteromultimer reveals nonspecific, non-enzymatic reactions (glycation), which are not detected under standard denaturing conditions. This competing reaction, which has hitherto been underestimated as a source of side products, can now be minimized. Optimization allowed access to the purest natural form of Herceptin to date (≥90 %). Moreover, through the use of a small library of sugars containing non-natural functional groups, Ab variants containing defined numbers of selectively addressable chemical tags (reaction handles at Sia C1) in specific positions (for attachment of cargo molecules or "glycorandomization") were readily generated. PMID:26756880

  19. A new synthetic access to 2-N-(glycosyl)thiosemicarbazides from 3-N-(glycosyl)oxadiazolinethiones and the regioselectivity of the glycosylation of their oxadiazolinethione precursors

    PubMed Central

    El Tamany, El Sayed H; Fattah, Mohy El Din Abdel; Aly, Mohamed R E; Boraei, Ahmed T A; Duerkop, Axel

    2013-01-01

    Summary Glycosylations of 5-(1H-indol-2-yl)-1,3,4-oxadiazoline-2(3H)-thione delivered various degrees of S- and/or N-glycosides depending on the reaction conditions. S-Glycosides were obtained regiospecifically by grinding oxadiazolinethiones with acylated α-D-glycosyl halides in basic alumina, whereas 3-N-(glycosyl)oxadiazolinethiones were selectively obtained by reaction with HgCl2 followed by heating the resultant chloromercuric salt with α-D-glycosyl halides in toluene under reflux. On using Et3N or K2CO3 as a base, mixtures of S- (major degree) and N-glycosides (minor degree) were obtained. Pure 3-N-(glycosyl)oxadiazolinethiones can also be selectively obtained from glycosylsulfanyloxadiazoles by the thermal S→N migration of the glycosyl moiety, which is proposed to occur by a tight-ion-pair mechanism. Thermal S→N migration of the glycosyl moiety can be used for purification of mixtures of S- or N-glycosides to obtain the pure N-glycosides. The aminolysis of the respective S- or N-glycosides with ammonia in aqueous methanol served as further confirmation of their structures. While in S-glycosides the glycosyl moiety was cleaved off again, 3-N-(glycosyl)oxadiazolinethiones showed a ring opening of the oxadiazoline ring (without affecting the glycosyl moiety) to give N-(glycosyl)thiosemicarbazides. Herewith, a new synthetic access to one of the four classes of glycosylthiosemicarbazides was found. The ultimate confirmation of new structures was achieved by X-ray crystallography. Finally, action of ammonia on benzylated 3-N-(galactosyl)oxadiazolinethione unexpectedly yielded 3-N-(galactosyl)triazolinethione. This represents a new path to the conversion of glycosyloxadiazolinethiones to new glycosyltriazolinethione nucleosides, which was until now unknown. PMID:23400104

  20. N-glycosylation requirements in neuromuscular synaptogenesis

    PubMed Central

    Parkinson, William; Dear, Mary Lynn; Rushton, Emma; Broadie, Kendal

    2013-01-01

    Neural development requires N-glycosylation regulation of intercellular signaling, but the requirements in synaptogenesis have not been well tested. All complex and hybrid N-glycosylation requires MGAT1 (UDP-GlcNAc:α-3-D-mannoside-β1,2-N-acetylglucosaminyl-transferase I) function, and Mgat1 nulls are the most compromised N-glycosylation condition that survive long enough to permit synaptogenesis studies. At the Drosophila neuromuscular junction (NMJ), Mgat1 mutants display selective loss of lectin-defined carbohydrates in the extracellular synaptomatrix, and an accompanying accumulation of the secreted endogenous Mind the gap (MTG) lectin, a key synaptogenesis regulator. Null Mgat1 mutants exhibit strongly overelaborated synaptic structural development, consistent with inhibitory roles for complex/hybrid N-glycans in morphological synaptogenesis, and strengthened functional synapse differentiation, consistent with synaptogenic MTG functions. Synapse molecular composition is surprisingly selectively altered, with decreases in presynaptic active zone Bruchpilot (BRP) and postsynaptic Glutamate receptor subtype B (GLURIIB), but no detectable change in a wide range of other synaptic components. Synaptogenesis is driven by bidirectional trans-synaptic signals that traverse the glycan-rich synaptomatrix, and Mgat1 mutation disrupts both anterograde and retrograde signals, consistent with MTG regulation of trans-synaptic signaling. Downstream of intercellular signaling, pre- and postsynaptic scaffolds are recruited to drive synaptogenesis, and Mgat1 mutants exhibit loss of both classic Discs large 1 (DLG1) and newly defined Lethal (2) giant larvae [L(2)GL] scaffolds. We conclude that MGAT1-dependent N-glycosylation shapes the synaptomatrix carbohydrate environment and endogenous lectin localization within this domain, to modulate retention of trans-synaptic signaling ligands driving synaptic scaffold recruitment during synaptogenesis. PMID:24227656

  1. Nonenzymatic glycosylation of bovine myelin basic protein

    SciTech Connect

    Hitz, J.B.

    1987-01-01

    In the CNS myelin sheath the nonenzymatic glycosylation reaction (at the early stage of the Amadori product) occurs only with the myelin basic protein and not with the other myelin proteins. This was observed in isolated bovine myelin by in vitro incubation with (/sup 14/C)-galactose and (/sup 14/C)-glucose. The respective in-vitro incorporation rates for purified bovine myelin basic protein with D-galactose, D-glucose and D-mannose were 7.2, 2.4 and 2.4 mmoles/mole myelin basic protein per day at 37/sup 0/C. A more rapid, HPLC method was devised and characterized to specifically analyze for the Amadori product. The HPLC method was correlated to the (/sup 14/C)-sugar incorporation method for myelin basic protein under a set of standard reaction conditions using (/sup 14/C)-glucose and (/sup 14/C)-mannose with HPLC values at 1/6 and 1/5 of the (/sup 14/C)-sugar incorporation method. A novel myelin basic protein purification step has been developed that yields a relativity proteolytic free preparation that is easy to work with, being totally soluble at a neutral pH. Nine new spots appear for a trypsinized glycosylated MBP in the paper peptide map of which eight correspond to positions of the (/sup 3/H)-labeled Amadori product in affinity isolated peptides. These studies provide a general characterization of and a structural basis for investigations on nonenzymatically glycosylated MBP as well as identifying MBP as the only nonenzymatically glycosylated protein in the CNS myelin sheath which may accumulate during aging, diabetes, and demyelinating diseases in general.

  2. Glycosylation Substrate Specificity of Pseudomonas aeruginosa 1244 Pilin*S

    PubMed Central

    Horzempa, Joseph; Comer, Jason E.; Davis, Sheila A.; Castric, Peter

    2008-01-01

    The β-carbon of the Pseudomonas aeruginosa 1244 pilin C-terminal Ser is a site of glycosylation. The present study was conducted to determine the pilin structures necessary for glycosylation. It was found that although Thr could be tolerated at the pilin C terminus, the blocking of the Ser carboxyl group with the addition of an Ala prevented glycosylation. Pilin from strain PA103 was not glycosylated by P. aeruginosa 1244, even when the C-terminal residue was converted to Ser. Substituting the disulfide loop region of strain PA103 pilin with that of strain 1244 allowed glycosylation to take place. Neither conversion of 1244 pilin disulfide loop Cys residues to Ala nor the deletion of segments of this structure prevented glycosylation. It was noted that the PA103 pilin disulfide loop environment was electronegative, whereas that of strain 1244 pilin had an overall positive charge. Insertion of a positive charge into the PA103 pilin disulfide loop of a mutant containing Ser at the C terminus allowed glycosylation to take place. Extending the “tail” region of the PA103 mutant pilin containing Ser at its terminus resulted in robust glycosylation. These results suggest that the terminal Ser is the major pilin glycosylation recognition feature and that this residue cannot be substituted at its carboxyl group. Although no other specific recognition features are present, the pilin surface must be compatible with the reaction apparatus for glycosylation to occur. PMID:16286455

  3. Glycosylation in immune cell trafficking

    PubMed Central

    Sperandio, Markus; Gleissner, Christian A.; Ley, Klaus

    2009-01-01

    Summary Leukocyte recruitment encompasses cell adhesion and activation steps that enable circulating leukocytes to roll, arrest, and firmly adhere on the endothelial surface before they extravasate into distinct tissue locations. This complex sequence of events relies on adhesive interactions between surface structures on leukocytes and endothelial cells and also on signals generated during the cell-cell contacts. Cell surface glycans play a crucial role in leukocyte recruitment. Several glycosyltransferases such as α1,3 fucosyltransferases, α2,3 sialyltransferases, core 2 N-acetylglucosaminlytransferases, β1,4 galactosyltransferases and polypeptide N-acetylgalactosaminyltransferases have been implicated in the generation of functional selectin ligands that mediate leukocyte rolling via binding to selectins. Recent evidence also suggests a role of α2,3 sialylated carbohydrate determinants in triggering chemokine-mediated leukocyte arrest and influencing β1 integrin function. Additional mechanisms by galectin- and siglec-dependent processes contribute to the growing number of reports emphasizing the significant role of glycans for the successful recruitment of leukocytes into tissues. Advancing the knowledge on glycan function into appropriate pathology models is likely to suggest interesting new therapeutic strategies in the treatment of immune- and inflammation-mediated diseases. PMID:19594631

  4. Diversity in Protein Glycosylation among Insect Species

    PubMed Central

    Vandenborre, Gianni; Smagghe, Guy; Ghesquière, Bart; Menschaert, Gerben; Nagender Rao, Rameshwaram; Gevaert, Kris; Van Damme, Els J. M.

    2011-01-01

    Background A very common protein modification in multicellular organisms is protein glycosylation or the addition of carbohydrate structures to the peptide backbone. Although the Class of the Insecta is the largest animal taxon on Earth, almost all information concerning glycosylation in insects is derived from studies with only one species, namely the fruit fly Drosophila melanogaster. Methodology/Principal Findings In this report, the differences in glycoproteomes between insects belonging to several economically important insect orders were studied. Using GNA (Galanthus nivalis agglutinin) affinity chromatography, different sets of glycoproteins with mannosyl-containing glycan structures were purified from the flour beetle (Tribolium castaneum), the silkworm (Bombyx mori), the honeybee (Apis mellifera), the fruit fly (D. melanogaster) and the pea aphid (Acyrthosiphon pisum). To identify and characterize the purified glycoproteins, LC-MS/MS analysis was performed. For all insect species, it was demonstrated that glycoproteins were related to a broad range of biological processes and molecular functions. Moreover, the majority of glycoproteins retained on the GNA column were unique to one particular insect species and only a few glycoproteins were present in the five different glycoprotein sets. Furthermore, these data support the hypothesis that insect glycoproteins can be decorated with mannosylated O-glycans. Conclusions/Significance The results presented here demonstrate that oligomannose N-glycosylation events are highly specific depending on the insect species. In addition, we also demonstrated that protein O-mannosylation in insect species may occur more frequently than currently believed. PMID:21373189

  5. Glycosylation modulates arenavirus glycoprotein expression and function

    SciTech Connect

    Bonhomme, Cyrille J. Capul, Althea A. Lauron, Elvin J. Bederka, Lydia H. Knopp, Kristeene A. Buchmeier, Michael J.

    2011-01-20

    The glycoprotein of lymphocytic choriomeningitis virus (LCMV) contains nine potential N-linked glycosylation sites. We investigated the function of these N-glycosylations by using alanine-scanning mutagenesis. All the available sites were occupied on GP1 and two of three on GP2. N-linked glycan mutations at positions 87 and 97 on GP1 resulted in reduction of expression and absence of cleavage and were necessary for downstream functions, as confirmed by the loss of GP-mediated fusion activity with T87A and S97A mutants. In contrast, T234A and E379N/A381T mutants impaired GP-mediated cell fusion without altered expression or processing. Infectivity via virus-like particles required glycans and a cleaved glycoprotein. Glycosylation at the first site within GP2, not normally utilized by LCMV, exhibited increased VLP infectivity. We also confirmed the role of the N-linked glycan at position 173 in the masking of the neutralizing epitope GP-1D. Taken together, our results indicated a strong relationship between fusion and infectivity.

  6. [The alterations of proteins glycosylation in rheumatic diseases].

    PubMed

    Chludzińska, Anna; Chrostek, Lech; Cylwik, Bogdan

    2012-08-01

    The alterations in glycosylation of serum glycoproteins were reported in several pathological conditions including rheumatic diseases. The many studies demonstrated the occurrence of some differentially glycosylated plasma immunoglobulins, especially IgG in rheumatoid arthritis. The most characteristic features are the decrease in galactose content, the presence of N-acetylglucosamine and the increase in fucose content. The structure of oligosaccharides attached to the antibody Fc region affect the pharmacokinetics and antibody effector functions of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. The changes in immunoglobulin glycosylation was suggested to be important in the etiology of rheumatoid athritis and correlated with the disease severity. In addition to impaired glycosylation of imunoglubulins, in rheumatic diseases exist the disturbances in glycosylation of both acute-phase and non acute-phase response, such as alpha-1 acid glycoprotein, haptoglobin and alpha-2 macroglobulin. The alterations in glycosylation of these glycoproteins were also correlated with the disease activity. PMID:23009010

  7. 21 CFR 864.7470 - Glycosylated hemoglobin assay.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... diabetes and to determine the proper insulin dosage for a patient. Elevated levels of glycosylated hemoglobin indicate uncontrolled diabetes in a patient. (b) Classification. Class II (performance standards)....

  8. 21 CFR 864.7470 - Glycosylated hemoglobin assay.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... diabetes and to determine the proper insulin dosage for a patient. Elevated levels of glycosylated hemoglobin indicate uncontrolled diabetes in a patient. (b) Classification. Class II (performance standards)....

  9. Incubation of selected fermentable fibres with feline faecal inoculum: correlations between in vitro fermentation characteristics and end products.

    PubMed

    Rochus, Kristel; Bosch, Guido; Vanhaecke, Lynn; Van de Velde, Hannelore; Depauw, Sarah; Xu, Jia; Fievez, Veerle; Van de Wiele, Tom; Hendriks, Wouter Hendrikus; Paul Jules Janssens, Geert; Hesta, Myriam

    2013-01-01

    This study aimed to evaluate correlations between fermentation characteristics and end products of selected fermentable fibres (three types of fructans, citrus pectin, guar gum), incubated with faecal inocula from donor cats fed two diets, differing in fibre and protein sources and concentrations. Cumulative gas production was measured over 72 h, fermentation end products were analysed at 4, 8, 12, 24, 48 and 72 h post-incubation, and quantification of lactobacilli, bifidobacteria and bacteroides in fermentation liquids were performed at 4 and 48 h of incubation. Partial Pearson correlations, corrected for inoculum, were calculated to assess the interdependency of the fermentation characteristics of the soluble fibre substrates. Butyric and valeric acid concentrations increased with higher fermentation rates, whereas acetic acid declined. Concentrations of butyric acid (highest in fructans) and propionic acid were inversely correlated with protein fermentation end products at several time points, whereas concentrations of acetic acid (highest in citrus pectin) were positively correlated with these products at most time points. Remarkably, a lack of clear relationship between the counts of bacterial groups and their typically associated products after 4 h of incubation was observed. Data from this experiment suggest that differences in fibre fermentation rate in feline faecal inocula coincide with typical changes in the profile of bacterial fermentation products. The observed higher concentrations of propionic and butyric acid as a result of fibre fermentation could possibly have beneficial effects on intestinal health, and may be confounded with a concurrent decrease in the production of putrefactive compounds. In conclusion, supplementing guar gum or fructans to a feline diet might be more advantageous compared with citrus pectin. However, in vivo research is warranted to confirm these conclusions in domestic cats. PMID:23952674

  10. Diversity of glycosyl hydrolase enzymes from metagenome and their application in food industry.

    PubMed

    Sathya, T A; Khan, Mahejibin

    2014-11-01

    Traditional use of enzymes for food processing and production of food ingredients resulted in fast-growing enzyme industries world over. The advances in technologies gave rise to exploring newer enzymes and/or modified enzymes for specific application. Search for novel enzymes that can augment catalytic efficiency and advances in molecular biology techniques including sequencing has targeted microbial diversity through metagenomic approaches for sourcing enzymes from difficult to culture organisms. Such mining studies have received more attention in characterizing hydrolases, their prevalence, broad substrate specificities, stability, and independence of cofactors. The focus on glycosyl hydrolases from metagenome for their application in food sector is reviewed. PMID:25311940

  11. Glycosylation of plant produced human antibodies.

    PubMed

    Kallolimath, Somanath; Steinkellner, Herta

    2015-12-23

    Human immunoglobulins circulate as highly heterogeneously glycosylated mixture of otherwise homogeneous protein backbones. A series of studies, mainly on IgG, have unequivocally proven that antibodies modulate their effector function through sugars present in the Fc domain. However, our limited technology in producing complex proteins such as antibodies, with defined glycan structures hamper in depths studies. This review introduces a plant based expression platform enabling engineering of antibody glycans. The procedure is based on the simultaneous delivery of appropriate constructs, carrying cDNAs of target proteins (e.g. heavy and light chain of antibodies) in combination with human glycosylation enzymes into plant leaves. Harvesting of recombinant proteins one week post construct delivery allows high speed and flexibility. Major achievements include the production of functional active slialylated pentameric IgMs in tobacco leaves. The system provides a viable approach to the generation of antibodies with defined glycoforms on demand, contributing to studies on antibody glycans and the development of novel antibody based drugs. PMID:27472861

  12. A comparison of the estimates of whole-body protein turnover in parenterally fed neonates obtained using three different end products.

    PubMed

    Pencharz, P; Beesley, J; Sauer, P; Van Aerde, J; Canagarayar, U; Renner, J; McVey, M; Wesson, D; Swyer, P

    1989-06-01

    Protein turnover rates in neonates have been calculated largely by measuring urinary [15N]urea enrichment following administration of [15N]glycine. Although ammonia has been increasingly recognized as an end product of nitrogen metabolism, in neonates it yields a different estimate of protein turnover than does urea. Comparisons of ammonia and urea end products in parenterally fed neonates have not previously been reported. A third and independent way of estimating protein turnover, developed for adults, is to use breath 13CO2 as an end product following administration of [1-13C]leucine. We therefore carried out simultaneous measurements of protein turnover in 10 parenterally fed neonates, using the three end products. The infants were clinically stable, weighed 2.6 +/- 0.2 kg, and received 3.1 +/- 0.2 g.kg-1.d-1 of amino acid, 2.2 +/- 0.1 g.kg-1.d-1 of lipids, and an energy intake of 90 +/- 4 kcal.kg-1.d-1 (1 kcal = 4.186 kJ). The turnover estimates derived from the 13CO2 and [15N]urea end products were very similar. The [15N]ammonia end product produced values approximately 66% (p less than 0.01) of the other two. We conclude that the ammonia and urea end products probably originate in different precursor pools. The similarity of the urea and breath carbon dioxide results helps validate the use of the urea end product in studying the nitrogen metabolism of parenterally fed neonates. Ideally in future studies two or more end products should be used, since they provide information about different aspects of the neonates' protein metabolism. PMID:2505915

  13. Analysis of glycosylation motifs and glycosyltransferases in Bacteria and Archaea.

    PubMed

    Tabish, Syed; Raza, Abbas; Nasir, Arshan; Zafar, Sadia; Bokhari, Habib

    2011-01-01

    The process of glycosylation has been studied extensively in prokaryotes but many questions still remain unanswered. Glycosyltransferase is the enzyme which mediates glycosylation and has its preference for the target glycosylation sites as well as for the type of glycosylation i.e. N-linked and O-linked glycosylation. In this study we carried out the bioinformatics analysis of one of the key enzymes of pgl locus from Campylobacter jejuni, known as PglB, which is distributed widely in bacteria and AglB from archaea. Relatively little sequence similarity was observed in the archaeal AglB(s) as compared to those of the bacterial PglB(s). In addition we tried to the answer the question of as to why not all the sequins Asp-X-Ser/Thr have an equal opportunity to be glycosylated by looking at the influence of the neighboring amino acids but no significant conserved pattern of the flanking sites could be identified. The software tool was developed to predict the potential glycosylation sites in autotransporter protein, the virulence factors of gram negative bacteria, and our results revealed that the frequency of glycosylation sites was higher in adhesins (a subclass of autotransporters) relative to the other classes of autotransporters. PMID:21738312

  14. Glycosylation of Cellulases: Engineering Better Enzymes for Biofuels.

    PubMed

    Greene, Eric R; Himmel, Michael E; Beckham, Gregg T; Tan, Zhongping

    2015-01-01

    Cellulose in plant cell walls is the largest reservoir of renewable carbon on Earth. The saccharification of cellulose from plant biomass into soluble sugars can be achieved using fungal and bacterial cellulolytic enzymes, cellulases, and further converted into fuels and chemicals. Most fungal cellulases are both N- and O-glycosylated in their native form, yet the consequences of glycosylation on activity and structure are not fully understood. Studying protein glycosylation is challenging as glycans are extremely heterogeneous, stereochemically complex, and glycosylation is not under direct genetic control. Despite these limitations, many studies have begun to unveil the role of cellulase glycosylation, especially in the industrially relevant cellobiohydrolase from Trichoderma reesei, Cel7A. Glycosylation confers many beneficial properties to cellulases including enhanced activity, thermal and proteolytic stability, and structural stabilization. However, glycosylation must be controlled carefully as such positive effects can be dampened or reversed. Encouragingly, methods for the manipulation of glycan structures have been recently reported that employ genetic tuning of glycan-active enzymes expressed from homogeneous and heterologous fungal hosts. Taken together, these studies have enabled new strategies for the exploitation of protein glycosylation for the production of enhanced cellulases for biofuel production. PMID:26613815

  15. Combining UHPLC-High Resolution MS and Feeding of Stable Isotope Labeled Polyketide Intermediates for Linking Precursors to End Products.

    PubMed

    Klitgaard, Andreas; Frandsen, Rasmus J N; Holm, Dorte K; Knudsen, Peter B; Frisvad, Jens C; Nielsen, Kristian F

    2015-07-24

    We present the results from stable isotope labeled precursor feeding studies combined with ultrahigh performance liquid chromatography-high resolution mass spectrometry for the identification of labeled polyketide (PK) end-products. Feeding experiments were performed with (13)C8-6-methylsalicylic acid (6-MSA) and (13)C14-YWA1, both produced in-house, as well as commercial (13)C7-benzoic acid and (2)H7-cinnamic acid, in species of Fusarium, Byssochlamys, Aspergillus, and Penicillium. Incorporation of 6-MSA into terreic acid or patulin was not observed in any of six evaluated species covering three genera, because the 6-MSA was shunted into (2Z,4E)-2-methyl-2,4-hexadienedioic acid. This indicates that patulin and terreic acid may be produced in a closed compartment of the cell and that (2Z,4E)-2-methyl-2,4-hexadienedioic acid is a detoxification product toward terreic acid and patulin. In Fusarium spp., YWA1 was shown to be incorporated into aurofusarin, rubrofusarin, and antibiotic Y. In A. niger, benzoic acid was shown to be incorporated into asperrubrol. Incorporation levels of 0.7-20% into the end-products were detected in wild-type strains. Thus, stable isotope labeling is a promising technique for investigation of polyketide biosynthesis and possible compartmentalization of toxic metabolites. PMID:26132344

  16. Phytoremediation of heavy metals by calcifying macro-algae (Nitella pseudoflabellata): implications of redox insensitive end products.

    PubMed

    Gomes, Pattiyage I A; Asaeda, Takashi

    2013-08-01

    To evaluate the phytoremediation of heavy metals in water and understand the biochemistry of end products of calcifying macro algae (charophytes), an 84-wk laboratory experiment was conducted. Eighteen microcosms were maintained with and without plants. These were given different heavy metal treatments: no heavy metals, 0.2mgL(-1) Cr(6+) and 0.01mgL(-1) Cd. Accumulation observed to be 0.06% Cr by dry weight and for Cd it was 0.02%. The bioconcentration factors were 3000 and 25000 for Cr and Cd, respectively. Ratios of heavy metal accumulation in alkaline (i.e., calcified areas) to acidic areas of plants were 6 to 4 (for Cr) and 1 to 1 (for Cd). This elucidated an association between heavy metal accumulation and calcification. This was validated by sequential extraction of sediments. It was shown that in microcosms with plants, the heavy metals were mainly in redox insensitive and less bioavailable carbonate bound form (39-47%). This was followed by organic-bound form (23-34%). Carbonate bound end products will ensure long term storage of heavy metals and after plant senescence these will not re-enter the water column. PMID:23773443

  17. The genetics of glycosylation in Gram-negative bacteria.

    PubMed

    Power, P M; Jennings, M P

    2003-01-28

    In recent years there has been a dramatic increase in reports of glycosylation of proteins in various Gram-negative systems including Neisseria meningitidis, Neisseria gonorrhoeae, Campylobacter jejuni, Pseudomonas aeruginosa, Escherichia coli, Caulobacter crescentus, Aeromonas caviae and Helicobacter pylori. Although this growing list contains many important pathogens (reviewed by Benz and Schmidt [Mol. Microbiol. 45 (2002) 267-276]) and the glycosylations are found on proteins important in pathogenesis such as pili, adhesins and flagella the precise role(s) of the glycosylation of these proteins remains to be determined. Furthermore, the details of the glycosylation biosynthetic process have not been determined in any of these systems. The definition of the precise role of glycosylation and the mechanism of biosynthesis will be facilitated by a detailed understanding of the genes involved. PMID:12586395

  18. A selective and mild glycosylation method of natural phenolic alcohols

    PubMed Central

    Poláková, Monika

    2016-01-01

    Summary Several bioactive natural p-hydroxyphenylalkyl β-D-glucopyranosides, such as vanillyl β-D-glucopyranoside, salidroside and isoconiferin, and their glycosyl analogues were prepared by a simple reaction sequence. The highly efficient synthetic approach was achieved by utilizing acetylated glycosyl bromides as well as aromatic moieties and mild glycosylation promoters. The aglycones, p-O-acetylated arylalkyl alcohols, were prepared by the reduction of the corresponding acetylated aldehydes or acids. Various stereoselective 1,2-trans-O-glycosylation methods were studied, including the DDQ–iodine or ZnO–ZnCl2 catalyst combination. Among them, ZnO–iodine has been identified as a new glycosylation promoter and successfully applied to the stereoselective glycoside synthesis. The final products were obtained by conventional Zemplén deacetylation. PMID:27340444

  19. Micropinocytic Ingestion of Glycosylated Albumin by Isolated Microvessels: Possible Role in Pathogenesis of Diabetic Microangiopathy

    NASA Astrophysics Data System (ADS)

    Williams, Stuart K.; Devenny, James J.; Bitensky, Mark W.

    1981-04-01

    Microvessels isolated from rat epididymal fat exhibit differential vesicular ingestion rates for unmodified and nonenzymatically glycosylated rat albumin. While unmodified rat albumin is excluded from ingestion by endothelial micropinocytic vesicles, glycosylated albumin is avidly taken up by endocytosis. Interaction of albumin and glycosylated albumin with endothelium was studied with a double-label fluorescence assay of micropinocytosis. When glycosylated albumin was present at a concentration of 6% with respect to total albumin (the level found in ``non diabetic'' serum), only glycosylated albumin was ingested. At higher concentrations of glycosylated albumin (those found in diabetic serum), both albumin and glycosylated albumin are ingested. Glycosylation of endothelial membrane components results in stimulated ingestion of glycosylated albumin, persistent exclusion of unmodified albumin, and unaltered micropinocytic ingestion of native ferritin. These results indicate that nonenzymatic glycosylation of serum albumin may result in rapid vesicle-mediated extravasation of albumin. Chronic microvascular leakage of glycosylated albumin could contribute to the pathogenesis of diabetic microangiopathy.

  20. Glycosylation, Hypogammaglobulinemia, and Resistance to Viral Infections

    PubMed Central

    Chun, Tae-Wook; Lusso, Paolo; Kaplan, Gerardo; Wolfe, Lynne; Memoli, Matthew J.; He, Miao; Vega, Hugo; Kim, Leo J.Y.; Huang, Yan; Hussein, Nadia; Nievas, Elma; Mitchell, Raquel; Garofalo, Mary; Louie, Aaron; Ireland, Derek C.; Grunes, Claire; Cimbro, Raffaello; Patel, Vyomesh; Holzapfel, Genevieve; Salahuddin, Daniel; Bristol, Tyler; Adams, David; Marciano, Beatriz E.; Hegde, Madhuri; Li, Yuxing; Calvo, Katherine R.; Stoddard, Jennifer; Justement, J. Shawn; Jacques, Jerome; Priel, Debra A. Long; Murray, Danielle; Sun, Peter; Kuhns, Douglas B.; Boerkoel, Cornelius F.; Chiorini, John A.; Di Pasquale, Giovanni; Verthelyi, Daniela; Rosenzweig, Sergio D.

    2014-01-01

    Summary Genetic defects in MOGS, the gene encoding mannosyl-oligosaccharide glucosidase (the first enzyme in the processing pathway of N-linked oligosaccharide), cause the rare congenital disorder of glycosylation type IIb (CDG-IIb), also known as MOGS-CDG. MOGS is expressed in the endoplasmic reticulum and is involved in the trimming of N-glycans. We evaluated two siblings with CDG-IIb who presented with multiple neurologic complications and a paradoxical immunologic phenotype characterized by severe hypogammaglobulinemia but limited clinical evidence of an infectious diathesis. A shortened immunoglobulin half-life was determined to be the mechanism underlying the hypogammaglobulinemia. Impaired viral replication and cellular entry may explain a decreased susceptibility to infections. PMID:24716661

  1. N-glycosylation of Colorectal Cancer Tissues

    PubMed Central

    Balog, Crina I. A.; Stavenhagen, Kathrin; Fung, Wesley L. J.; Koeleman, Carolien A.; McDonnell, Liam A.; Verhoeven, Aswin; Mesker, Wilma E.; Tollenaar, Rob A. E. M.; Deelder, André M.; Wuhrer, Manfred

    2012-01-01

    Colorectal cancer is the third most common cancer worldwide with an annual incidence of ∼1 million cases and an annual mortality rate of ∼655,000 individuals. There is an urgent need for identifying novel targets to develop more sensitive, reliable, and specific tests for early stage detection of colon cancer. Post-translational modifications are known to play an important role in cancer progression and immune surveillance of tumors. In the present study, we compared the N-glycan profiles from 13 colorectal cancer tumor tissues and corresponding control colon tissues. The N-glycans were enzymatically released, purified, and labeled with 2-aminobenzoic acid. Aliquots were profiled by hydrophilic interaction liquid chromatography (HILIC-HPLC) with fluorescence detection and by negative mode MALDI-TOF-MS. Using partial least squares discriminant analysis to investigate the N-glycosylation changes in colorectal cancer, an excellent separation and prediction ability were observed for both HILIC-HPLC and MALDI-TOF-MS data. For structure elucidation, information from positive mode ESI-ion trap-MS/MS and negative mode MALDI-TOF/TOF-MS was combined. Among the features with a high separation power, structures containing a bisecting GlcNAc were found to be decreased in the tumor, whereas sulfated glycans, paucimannosidic glycans, and glycans containing a sialylated Lewis type epitope were shown to be increased in tumor tissues. In addition, core-fucosylated high mannose N-glycans were detected in tumor samples. In conclusion, the combination of HILIC and MALDI-TOF-MS profiling of N-glycans with multivariate statistical analysis demonstrated its potential for identifying N-glycosylation changes in colorectal cancer tissues and provided new leads that might be used as candidate biomarkers. PMID:22573871

  2. Glycosylation increases the thermostability of human aquaporin 10 protein.

    PubMed

    Öberg, Fredrik; Sjöhamn, Jennie; Fischer, Gerhard; Moberg, Andreas; Pedersen, Anders; Neutze, Richard; Hedfalk, Kristina

    2011-09-01

    Human aquaporin10 (hAQP10) is a transmembrane facilitator of both water and glycerol transport in the small intestine. This aquaglyceroporin is located in the apical membrane of enterocytes and is believed to contribute to the passage of water and glycerol through these intestinal absorptive cells. Here we overproduced hAQP10 in the yeast Pichia pastoris and observed that the protein is glycosylated at Asn-133 in the extracellular loop C. This finding confirms one of three predicted glycosylation sites for hAQP10, and its glycosylation is unique for the human aquaporins overproduced in this host. Nonglycosylated protein was isolated using both glycan affinity chromatography and through mutating asparagine 133 to a glutamine. All three forms of hAQP10 where found to facilitate the transport of water, glycerol, erythritol, and xylitol, and glycosylation had little effect on functionality. In contrast, glycosylated hAQP10 showed increased thermostability of 3-6 °C compared with the nonglycosylated protein, suggesting a stabilizing effect of the N-linked glycan. Because only one third of hAQP10 was glycosylated yet the thermostability titration was mono-modal, we suggest that the presence of at least one glycosylated protein within each tetramer is sufficient to convey an enhanced structural stability to the remaining hAQP10 protomers of the tetramer. PMID:21733844

  3. Ceramide Glycosylation Catalyzed by Glucosylceramide Synthase and Cancer Drug Resistance

    PubMed Central

    Liu, Yong-Yu; Li, Yu-Teh

    2014-01-01

    Glucosylceramide synthase (GCS), converting ceramide to glucosylceramide, catalyzes the first reaction of ceramide glycosylation in sphingolipid metabolism. This glycosylation by GCS is a critical step regulating the modulation of cellular activities by controlling ceramide and glycosphingolipids (GSLs). An increase of ceramide in response to stresses, such as chemotherapy, drives cells to proliferation arrest and apoptosis or autophagy; however, ceramide glycosylation promptly eliminates ceramide and consequently, these induced processes, thus protecting cancer cells. Furthermore, persistently enhanced ceramide glycosylation can increase GSLs, participating in selecting cancer cells to drug resistance. GCS is overexpressed in diverse drug-resistant cancer cells and in tumors of breast, colon, and leukemia that display poor response to chemotherapy. As ceramide glycosylation by GCS is a rate-limiting step in GSL synthesis, inhibition of GCS sensitizes cancer cells to anticancer drugs and eradicates cancer stem cells. Mechanistic studies indicate that uncoupling ceramide glycosylation can modulate gene expression, decreasing MDR1 through the cSrc/β-catenin pathway and restoring p53 expression via RNA splicing. These studies not only expand our knowledge in understanding how ceramide glycosylation affects cancer cells, but also provide novel therapeutic approaches for targeting refractory tumors. PMID:23290777

  4. Contribution of Cyclooxygenase End Products and Oxidative Stress to Intrahepatic Endothelial Dysfunction in Early Non-Alcoholic Fatty Liver Disease

    PubMed Central

    Morales Arraez, Dalia; Marcelino Reyes, Raquel; Abrante, Beatriz; Diaz-Flores, Felicitas; Salido, Eduardo; Quintero, Enrique; Hernández-Guerra, Manuel

    2016-01-01

    Introduction Metabolic syndrome induces endothelial dysfunction, a surrogate marker of cardiovascular disease. In parallel, metabolic syndrome is frequently associated with non-alcoholic fatty liver disease (NAFLD), which may progress to cirrhosis. The aim of the present study was to evaluate intrahepatic endothelial dysfunction related to cyclooxygenase end products and oxidative stress as possible mechanisms involved in the pathophysiology of NAFLD. Materials and Methods Sprague-Dawley rats were fed standard diet (control-diet, CD) or high-fat-diet (HFD) for 6 weeks. Metabolic syndrome was assessed by recording arterial pressure, lipids, glycemia and rat body weight. Splanchnic hemodynamics were measured, and endothelial dysfunction was evaluated using concentration-effect curves to acetylcholine. Response was assessed with either vehicle, L-NG-Nitroarginine (L-NNA), indomethacin, tempol, or a thromboxane receptor antagonist, SQ 29548. We quantified inflammation, fibrosis, oxidative stress, nitric oxide (NO) bioavailability and thromboxane B2 levels. Results HFD rats exhibited metabolic syndrome together with the presence of NAFLD. Compared to control-diet livers, HFD livers showed increased hepatic vascular resistance unrelated to inflammation or fibrosis, but with decreased NO activity and increased oxidative stress. Endothelial dysfunction was observed in HFD livers compared with CD rats and improved after cyclooxygenase inhibition or tempol pre-incubation. However, pre-incubation with SQ 29548 did not modify acetylcholine response. Conclusions Our study provides evidence that endothelial dysfunction at an early stage of NAFLD is associated with reduced NO bioavailability together with increased cyclooxygenase end products and oxidative stress, which suggests that both pathways are involved in the pathophysiology and may be worth exploring as therapeutic targets to prevent progression of the disease. PMID:27227672

  5. C1GALT1 enhances proliferation of hepatocellular carcinoma cells via modulating MET glycosylation and dimerization.

    PubMed

    Wu, Yao-Ming; Liu, Chiung-Hui; Huang, Miao-Juei; Lai, Hong-Shiee; Lee, Po-Huang; Hu, Rey-Heng; Huang, Min-Chuan

    2013-09-01

    Altered glycosylation is a hallmark of cancer. The core 1 β1,3-galactosyltransferase (C1GALT1) controls the formation of mucin-type O-glycans, far overlooked and underestimated in cancer. Here, we report that C1GALT1 mRNA and protein are frequently overexpressed in hepatocellular carcinoma tumors compared with nontumor liver tissues, where it correlates with advanced tumor stage, metastasis, and poor survival. Enforced expression of C1GALT1 was sufficient to enhance cell proliferation, whereas RNA interference-mediated silencing of C1GALT1 was sufficient to suppress cell proliferation in vitro and in vivo. Notably, C1GALT1 attenuation also suppressed hepatocyte growth factor (HGF)-mediated phosphorylation of the MET kinase in hepatocellular carcinoma cells, whereas enforced expression of C1GALT1 enhanced MET phosphorylation. MET blockade with PHA665752 inhibited C1GALT1-enhanced cell viability. In support of these results, we found that the expression level of phospho-MET and C1GALT1 were associated in primary hepatocellular carcinoma tissues. Mechanistic investigations showed that MET was decorated with O-glycans, as revealed by binding to Vicia villosa agglutinin and peanut agglutinin. Moreover, C1GALT1 modified the O-glycosylation of MET, enhancing its HGF-induced dimerization and activation. Together, our results indicate that C1GALT1 overexpression in hepatocellular carcinoma activates HGF signaling via modulation of MET O-glycosylation and dimerization, providing new insights into how O-glycosylation drives hepatocellular carcinoma pathogenesis. PMID:23832667

  6. Experimental nonenzymatic glycosylation of vitreous collagens occurs by two pathways.

    PubMed Central

    Pulido, J S

    1996-01-01

    PURPOSE: To study the process of nonenzymatic glycosolation of vitreous collagen in vitro to determine the contributions of the classic Maillard pathway and the oxidative pathway, as well as to evaluate possible inhibitors of both pathways. METHODS: Bovine vitreous collagen was extracted and then incubated with hexoses in vitro. The amount of advanced glycosylation end (AGE) products was measured by fluorometry under varying conditions in the presence and absence of glycosolation inhibitors. Oxygen consumption studies and electron spin resonance spectroscopy with and without free-radical inhibitors were performed to differentiate oxidative from nonoxidative glycosolation. RESULTS: Vitreous collagen undergoes nonenzymatic glycosolation in the presence of glucose or galactose in vitro. Oxygen consumption data show that oxygen is consumed in glucose and galactose solutions. Oxygen consumption is decreased by known free-radical inhibitors and rutin but not aminoguanidine. Electron spin resonance spectroscopy demonstrated the presence of a carbon-centered radical, and known free-radical inhibitors decreased the carbon-centered signal. CONCLUSIONS: Nonenzymatic glycosolation of vitreous collagen can occur not only by the classic nonoxidative pathway, but also by a second oxidative pathway that is susceptible to a number of inhibitors. PMID:8981718

  7. Glycosylated Synaptomatrix Regulation of Trans-Synaptic Signaling

    PubMed Central

    Dani, Neil; Broadie, Kendal

    2011-01-01

    Synapse formation is driven by precisely orchestrated intercellular communication between the presynaptic and the postsynaptic cell, involving a cascade of anterograde and retrograde signals. At the neuromuscular junction (NMJ), both neuron and muscle secrete signals into the heavily glycosylated synaptic cleft matrix sandwiched between the two synapsing cells. These signals must necessarily traverse and interact with the extracellular environment, for the ligand-receptor interactions mediating communication to occur. This complex synaptomatrix, rich in glycoproteins and proteoglycans, comprises heterogeneous, compartmentalized domains where specialized glycans modulate trans-synaptic signaling during synaptogenesis and subsequent synapse modulation. The general importance of glycans during development, homeostasis and disease is well established, but this important molecular class has received less study in the nervous system. Glycan modifications are now understood to play functional and modulatory roles as ligands and co-receptors in numerous model systems; however roles in synapse formation and modulation are less well understood. We highlight here properties of synaptomatrix glycans and glycan-interacting proteins with key roles in synaptogenesis, with a particular focus on recent advances made in the Drosophila NMJ genetic system. We discuss open questions and interesting new findings driving the current investigations of the complex, diverse and largely understudied glycan mechanisms. Keywords: Extracellular Matrix, Glycan, Synaptic Cleft, Neuromuscular Junction, Drosophila PMID:21509945

  8. Enhanced Aromatic Sequons Increase Oligosaccharyltransferase Glycosylation Efficiency and Glycan Homogeneity.

    PubMed

    Murray, Amber N; Chen, Wentao; Antonopoulos, Aristotelis; Hanson, Sarah R; Wiseman, R Luke; Dell, Anne; Haslam, Stuart M; Powers, David L; Powers, Evan T; Kelly, Jeffery W

    2015-08-20

    N-Glycosylation plays an important role in protein folding and function. Previous studies demonstrate that a phenylalanine residue introduced at the n-2 position relative to an Asn-Xxx-Thr/Ser N-glycosylation sequon increases the glycan occupancy of the sequon in insect cells. Here, we show that any aromatic residue at n-2 increases glycan occupancy in human cells and that this effect is dependent upon oligosaccharyltransferase substrate preferences rather than differences in other cellular processing events such as degradation or trafficking. Moreover, aromatic residues at n-2 alter glycan processing in the Golgi, producing proteins with less complex N-glycan structures. These results demonstrate that manipulating the sequence space surrounding N-glycosylation sequons is useful both for controlling glycosylation efficiency, thus enhancing glycan occupancy, and for influencing the N-glycan structures produced. PMID:26190824

  9. Analytical detection and characterization of biopharmaceutical glycosylation by MS.

    PubMed

    Oh, Myung Jin; Hua, Serenus; Kim, Unyong; Kim, Hyun Joong; Lee, Jua; Kim, Jae-Han; An, Hyun Joo

    2016-04-01

    Glycosylation plays an important role in ensuring the proper structure and function of most biotherapeutic proteins. Even small changes in glycan composition, structure, or location can have a drastic impact on drug safety and efficacy. Recently, glycosylation has become the subject of increased focus as biopharmaceutical companies rush to create not only biosimilars, but also biobetters based on existing biotherapeutic proteins. Against this backdrop of ongoing biopharmaceutical innovation, updated methods for accurate and detailed analysis of protein glycosylation are critical for biopharmaceutical companies and government regulatory agencies alike. This review summarizes current methods of characterizing biopharmaceutical glycosylation, including compositional mass profiling, isomer-specific profiling and structural elucidation by MS and hyphenated techniques. PMID:26964748

  10. Glycosyl dithiocarbamates: β-selective couplings without auxiliary groups.

    PubMed

    Padungros, Panuwat; Alberch, Laura; Wei, Alexander

    2014-03-21

    In this article, we evaluate glycosyl dithiocarbamates (DTCs) with unprotected C2 hydroxyls as donors in β-linked oligosaccharide synthesis. We report a mild, one-pot conversion of glycals into β-glycosyl DTCs via DMDO oxidation with subsequent ring opening by DTC salts, which can be generated in situ from secondary amines and CS2. Glycosyl DTCs are readily activated with Cu(I) or Cu(II) triflate at low temperatures and are amenable to reiterative synthesis strategies, as demonstrated by the efficient construction of a tri-β-1,6-linked tetrasaccharide. Glycosyl DTC couplings are highly β-selective despite the absence of a preexisting C2 auxiliary group. We provide evidence that the directing effect is mediated by the C2 hydroxyl itself via the putative formation of a cis-fused bicyclic intermediate. PMID:24548247

  11. Glycosyl Dithiocarbamates: β-Selective Couplings without Auxiliary Groups

    PubMed Central

    2015-01-01

    In this article, we evaluate glycosyl dithiocarbamates (DTCs) with unprotected C2 hydroxyls as donors in β-linked oligosaccharide synthesis. We report a mild, one-pot conversion of glycals into β-glycosyl DTCs via DMDO oxidation with subsequent ring opening by DTC salts, which can be generated in situ from secondary amines and CS2. Glycosyl DTCs are readily activated with Cu(I) or Cu(II) triflate at low temperatures and are amenable to reiterative synthesis strategies, as demonstrated by the efficient construction of a tri-β-1,6-linked tetrasaccharide. Glycosyl DTC couplings are highly β-selective despite the absence of a preexisting C2 auxiliary group. We provide evidence that the directing effect is mediated by the C2 hydroxyl itself via the putative formation of a cis-fused bicyclic intermediate. PMID:24548247

  12. Stability-increasing effects of anthocyanin glycosyl acylation.

    PubMed

    Zhao, Chang-Ling; Yu, Yu-Qi; Chen, Zhong-Jian; Wen, Guo-Song; Wei, Fu-Gang; Zheng, Quan; Wang, Chong-De; Xiao, Xing-Lei

    2017-01-01

    This review comprehensively summarizes the existing knowledge regarding the chemical implications of anthocyanin glycosyl acylation, the effects of acylation on the stability of acylated anthocyanins and the corresponding mechanisms. Anthocyanin glycosyl acylation commonly refers to the phenomenon in which the hydroxyl groups of anthocyanin glycosyls are esterified by aliphatic or aromatic acids, which is synthetically represented by the acylation sites as well as the types and numbers of acyl groups. Generally, glycosyl acylation increases the in vitro and in vivo chemical stability of acylated anthocyanins, and the mechanisms primarily involve physicochemical, stereochemical, photochemical, biochemical or environmental aspects under specific conditions. Additionally, the acylation sites as well as the types and numbers of acyl groups influence the stability of acylated anthocyanins to different degrees. This review could provide insight into the optimization of the stability of anthocyanins as well as the application of suitable anthocyanins in food, pharmaceutical and cosmetic industries. PMID:27507456

  13. Genetics Home Reference: ALG12-congenital disorder of glycosylation

    MedlinePlus

    ... particles and germs, marking them for destruction. A reduction in antibodies can make it difficult for affected ... called glycosylation. During this process, complex chains of sugar molecules (oligosaccharides) are added to proteins and fats ( ...

  14. Antigen-Specific Antibody Glycosylation Is Regulated via Vaccination

    PubMed Central

    Suscovich, Todd; Dionne, Kendall; Tedesco, Jacquelynne; Chung, Amy W.; Streeck, Hendrik; Pau, Maria; Schuitemaker, Hanneke; Francis, Don; Fast, Patricia; Laufer, Dagna; Walker, Bruce D.; Baden, Lindsey; Barouch, Dan H.; Alter, Galit

    2016-01-01

    Antibody effector functions, such as antibody-dependent cellular cytotoxicity, complement deposition, and antibody-dependent phagocytosis, play a critical role in immunity against multiple pathogens, particularly in the absence of neutralizing activity. Two modifications to the IgG constant domain (Fc domain) regulate antibody functionality: changes in antibody subclass and changes in a single N-linked glycan located in the CH2 domain of the IgG Fc. Together, these modifications provide a specific set of instructions to the innate immune system to direct the elimination of antibody-bound antigens. While it is clear that subclass selection is actively regulated during the course of natural infection, it is unclear whether antibody glycosylation can be tuned, in a signal-specific or pathogen-specific manner. Here, we show that antibody glycosylation is determined in an antigen- and pathogen-specific manner during HIV infection. Moreover, while dramatic differences exist in bulk IgG glycosylation among individuals in distinct geographical locations, immunization is able to overcome these differences and elicit antigen-specific antibodies with similar antibody glycosylation patterns. Additionally, distinct vaccine regimens induced different antigen-specific IgG glycosylation profiles, suggesting that antibody glycosylation is not only programmable but can be manipulated via the delivery of distinct inflammatory signals during B cell priming. These data strongly suggest that the immune system naturally drives antibody glycosylation in an antigen-specific manner and highlights a promising means by which next-generation therapeutics and vaccines can harness the antiviral activity of the innate immune system via directed alterations in antibody glycosylation in vivo.   PMID:26982805

  15. Hypoxic regulation of glycosylation via the N-acetylglucosamine cycle

    PubMed Central

    Shirato, Ken; Nakajima, Kazuki; Korekane, Hiroaki; Takamatsu, Shinji; Gao, Congxiao; Angata, Takashi; Ohtsubo, Kazuaki; Taniguchi, Naoyuki

    2011-01-01

    Glucose is an energy substrate, as well as the primary source of nucleotide sugars, which are utilized as donor substrates in protein glycosylation. Appropriate glycosylation is necessary to maintain the stability of protein, and is also important in the localization and trafficking of proteins. The dysregulation of glycosylation results in the development of a variety of disorders, such as cancer, diabetes mellitus and emphysema. Glycosylation is kinetically regulated by dynamically changing the portfolio of glycosyltransferases, nucleotide sugars, and nucleotide sugar transporters, which together form a part of what is currently referred to as the ”Glycan cycle”. An excess or a deficiency in the expression of glycosyltransferases has been shown to alter the glycosylation pattern, which subsequently leads to the onset, progression and exacerbation of a number of diseases. Furthermore, alterations in intracellular nucleotide sugar levels can also modulate glycosylation patterns. It is observed that pathological hypoxic microenvironments frequently occur in solid cancers and inflammatory foci. Hypoxic conditions dramatically change gene expression profiles, by activating hypoxia-inducible factor-1, which mediates adaptive cellular responses. Hypoxia-induced glycosyltransferases and nucleotide sugar transporters have been shown to modulate glycosylation patterns that are part of the mechanism associated with cancer metastasis. Hypoxia-inducible factor-1 also induces the expression of glucose transporters and various types of glycolytic enzymes, leading to shifts in glucose metabolic patterns. This fact strongly suggests that hypoxic conditions are an important factor in modulating various nucleotide sugar biosynthetic pathways. This review discusses some of the current thinking of how hypoxia alters glucose metabolic fluxes that can modulate cellular glycosylation patterns and consequently modify cellular functions, particularly from the standpoint of the N

  16. Antigen-Specific Antibody Glycosylation Is Regulated via Vaccination.

    PubMed

    Mahan, Alison E; Jennewein, Madeleine F; Suscovich, Todd; Dionne, Kendall; Tedesco, Jacquelynne; Chung, Amy W; Streeck, Hendrik; Pau, Maria; Schuitemaker, Hanneke; Francis, Don; Fast, Patricia; Laufer, Dagna; Walker, Bruce D; Baden, Lindsey; Barouch, Dan H; Alter, Galit

    2016-03-01

    Antibody effector functions, such as antibody-dependent cellular cytotoxicity, complement deposition, and antibody-dependent phagocytosis, play a critical role in immunity against multiple pathogens, particularly in the absence of neutralizing activity. Two modifications to the IgG constant domain (Fc domain) regulate antibody functionality: changes in antibody subclass and changes in a single N-linked glycan located in the CH2 domain of the IgG Fc. Together, these modifications provide a specific set of instructions to the innate immune system to direct the elimination of antibody-bound antigens. While it is clear that subclass selection is actively regulated during the course of natural infection, it is unclear whether antibody glycosylation can be tuned, in a signal-specific or pathogen-specific manner. Here, we show that antibody glycosylation is determined in an antigen- and pathogen-specific manner during HIV infection. Moreover, while dramatic differences exist in bulk IgG glycosylation among individuals in distinct geographical locations, immunization is able to overcome these differences and elicit antigen-specific antibodies with similar antibody glycosylation patterns. Additionally, distinct vaccine regimens induced different antigen-specific IgG glycosylation profiles, suggesting that antibody glycosylation is not only programmable but can be manipulated via the delivery of distinct inflammatory signals during B cell priming. These data strongly suggest that the immune system naturally drives antibody glycosylation in an antigen-specific manner and highlights a promising means by which next-generation therapeutics and vaccines can harness the antiviral activity of the innate immune system via directed alterations in antibody glycosylation in vivo.  . PMID:26982805

  17. Effects of preservation conditions of canine feces on in vitro gas production kinetics and fermentation end products.

    PubMed

    Bosch, G; Wrigglesworth, D J; Cone, J W; Pellikaan, W F; Hendriks, W H

    2013-01-01

    This study investigated the effect of chilling and freezing (for 24 h) canine feces on in vitro gas production kinetics and fermentation end product profiles from carbohydrate-rich (in vitro run 1) and protein-rich (in vitro run 2) substrates. Feces were collected from 3 adult retriever-type dogs fed a canned diet for at least 2 wk. Each fecal sample was divided into 3 portions: 1 portion was used immediately as an inoculum (fresh) and the other 2 portions were used after either chilling to 5°C for 30 min and storage in crushed ice for 23.5 h (chilling) or freezing to -20°C for 30 min and storage in a prefrozen (-20°C) container for 23.5 h (freezing). The medium solution for run 1 contained N whereas that for run 2 was N free. Substrates included fructooligosaccharide (FOS), sugar beet pulp, and wheat middlings in run 1 and soybean meal, poultry meat meal, and feather meal in run 2. Gas production kinetics were calculated from cumulative gas production data measured for 72 h. After incubation, fermentation liquids were analyzed for short-chain fatty acids, NH3, and aromatic compounds. For both in vitro runs, chilling feces did not affect gas production kinetics and end product profiles of substrates compared with inocula from fresh feces. Freezing feces decreased the maximum rate of gas production in phase 2 for FOS (P<0.001) and across substrates increased gas produced (P≤0.005) and time of maximum gas production in phase 2 (P<0.001). Furthermore, compared with fresh fecal inocula, inocula from frozen feces resulted in increased overall indole concentrations in run 1 (P=0.006) and indole concentrations from soybean meal and poultry meat meal in run 2 (P<0.001). In run 2, phenol concentrations were greater (P=0.015) for frozen feces than for fresh feces (P=0.015). In conclusion, freezing canine feces for 24 h slightly altered fermentative characteristics of fecal inoculum whereas chilling feces in crushed ice for 24 h maintained fermentative characteristics

  18. Glycosylation of Dentin Matrix Protein 1 is critical for osteogenesis

    PubMed Central

    Sun, Yao; Weng, Yuteng; Zhang, Chenyang; Liu, Yi; Kang, Chen; Liu, Zhongshuang; Jing, Bo; Zhang, Qi; Wang, Zuolin

    2015-01-01

    Proteoglycans play important roles in regulating osteogenesis. Dentin matrix protein 1 (DMP1) is a highly expressed bone extracellular matrix protein that regulates both bone development and phosphate metabolism. After glycosylation, an N-terminal fragment of DMP1 protein was identified as a new proteoglycan (DMP1-PG) in bone matrix. In vitro investigations showed that Ser89 is the key glycosylation site in mouse DMP1. However, the specific role of DMP1 glycosylation is still not understood. In this study, a mutant DMP1 mouse model was developed in which the glycosylation site S89 was substituted with G89 (S89G-DMP1). The glycosylation level of DMP1 was down-regulated in the bone matrix of S89G-DMP1 mice. Compared with wild type mice, the long bones of S89G-DMP1 mice showed developmental changes, including the speed of bone remodeling and mineralization, the morphology and activities of osteocytes, and activities of both osteoblasts and osteoclasts. These findings indicate that glycosylation of DMP1 is a key posttranslational modification process during development and that DMP1-PG functions as an indispensable proteoglycan in osteogenesis. PMID:26634432

  19. Glycosylation of Dentin Matrix Protein 1 is critical for osteogenesis.

    PubMed

    Sun, Yao; Weng, Yuteng; Zhang, Chenyang; Liu, Yi; Kang, Chen; Liu, Zhongshuang; Jing, Bo; Zhang, Qi; Wang, Zuolin

    2015-01-01

    Proteoglycans play important roles in regulating osteogenesis. Dentin matrix protein 1 (DMP1) is a highly expressed bone extracellular matrix protein that regulates both bone development and phosphate metabolism. After glycosylation, an N-terminal fragment of DMP1 protein was identified as a new proteoglycan (DMP1-PG) in bone matrix. In vitro investigations showed that Ser(89) is the key glycosylation site in mouse DMP1. However, the specific role of DMP1 glycosylation is still not understood. In this study, a mutant DMP1 mouse model was developed in which the glycosylation site S(89) was substituted with G(89) (S89G-DMP1). The glycosylation level of DMP1 was down-regulated in the bone matrix of S89G-DMP1 mice. Compared with wild type mice, the long bones of S89G-DMP1 mice showed developmental changes, including the speed of bone remodeling and mineralization, the morphology and activities of osteocytes, and activities of both osteoblasts and osteoclasts. These findings indicate that glycosylation of DMP1 is a key posttranslational modification process during development and that DMP1-PG functions as an indispensable proteoglycan in osteogenesis. PMID:26634432

  20. Definition of the bacterial N-glycosylation site consensus sequence.

    PubMed

    Kowarik, Michael; Young, N Martin; Numao, Shin; Schulz, Benjamin L; Hug, Isabelle; Callewaert, Nico; Mills, Dominic C; Watson, David C; Hernandez, Marcela; Kelly, John F; Wacker, Michael; Aebi, Markus

    2006-05-01

    The Campylobacter jejuni pgl locus encodes an N-linked protein glycosylation machinery that can be functionally transferred into Escherichia coli. In this system, we analyzed the elements in the C. jejuni N-glycoprotein AcrA required for accepting an N-glycan. We found that the eukaryotic primary consensus sequence for N-glycosylation is N terminally extended to D/E-Y-N-X-S/T (Y, X not equalP) for recognition by the bacterial oligosaccharyltransferase (OST) PglB. However, not all consensus sequences were N-glycosylated when they were either artificially introduced or when they were present in non-C. jejuni proteins. We were able to produce recombinant glycoproteins with engineered N-glycosylation sites and confirmed the requirement for a negatively charged side chain at position -2 in C. jejuni N-glycoproteins. N-glycosylation of AcrA by the eukaryotic OST in Saccharomyces cerevisiae occurred independent of the acidic residue at the -2 position. Thus, bacterial N-glycosylation site selection is more specific than the eukaryotic equivalent with respect to the polypeptide acceptor sequence. PMID:16619027